Texas coastal zone biotopes, an ecography Interim report for the Bay and Estuary Management Program (CRMP)

[From the U.S. Government Printing Office, www.gpo.gov]

Coastal Zone
Information
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Center
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TEXAS COASTAL ZONE MOTO PES:
AN ECOGRAPHY

Interim Report
for
The Bay and Estuary Management Program (CRMP)
--p

FOR THE
COASTAL RESOURCES MANAGEMENT PROGRAM
DIVISION OF PLANNING COORDINATION
OFFICE OF THE GOVERNOR

The University of Texas
Marine Science Institute
IA
QE November 1972
541 .5
.c6
06
1972

01697

U - S . DEPARTMENT OF COMMERCE NOAA
COASTAL SERVICES CENTER
2234 SOUTH HOFSON AVENUE
CHARLESTON, SC 29405-2413

TEXAS COASTAL ZONE BIOTOPES: AN ECOGRAPHY

Interim Report

for

The Bay and Estuary Management Program (CRMP)

Carl H. Oppenheimer Ph.D., Director

Kennith G. Gordon Ph.D.: Research Associate

University of Texas Marine Science

Institute at Port Aransas

FOR THE
COASTAL RESOURCES MANAGEMENT PROGRAM
DIVISION OF PLANNING COORDINATION
OFFICE OF THE GOVERNOR

November 1972

property of csc library

0e541.5.c6 06 1972 25521482 feb 20 1997

ACKNOWLEDGEMENTS

The biotope development was the result of a team approach in

combination with several other ecological studies of the Texas Bay

systems. The major portion of the artists renditions we---c 6rawn by

Marsha Kier with the assistance of David Walters. Biological and

literature editorial assistance was given by John Holland, Dorothy Paul,

Nancy Maciolek, Julie Gillespie, and Dinah Bowman. Thomas Isensee

offered valuable assistance during the final drafting of the report.

TEXAS COASTAL ZONE BIOTOPES: AN ECOGIRAPHY

Today's concern about the state of our coastal environment is

primarily related to estll-.etics, recreaCion, Or Sport and commercial

fisheries. Therefore we tend to associate any change created by man's

industry with the above parameters. As man's interesIC in the coastal

zone co.-'I-inues, it is essential that we define the above terms so tharc

natural or artificial changes can be evaluated. An c-stuary is described

schematically in Figure 1 (Phleger 1969). We must also recognize that

our present day bays have been altered by manis many activities with

both beneficial and adverse results. The original sh.-Ilow bays with

restricted passes to the Gulf of Mexico were subjected to Large

fluctuations in salinity as alternate weather patterns of rainfall and

drought occurred. To some degree man.-. has changed this variable condition

through increasing control of the bays resulting from construction of

darns and ship channels.

Esthetics (Figure 2) is a very difficult concept to evaluate or

identify. To some the change of an estuary to a modern well-designed

marina is acceptable. Who can deny that a marina (Pigure 3), with its

picturesque sailboats@ motor cruisers and accompanying buildings with.

tennis courts and swimming pools, is attractive? Yet such modifications

alter the biological community in some ways and certainly alter the

.natural environment. At the same time, our natural environment is

finite. Therefore some form of management must be developed to assure

both esthetic and Lunctional uses of the coastal zone (Figures 4 and 5).

Because esthetics, biological environment and -@hysiography are

so Interrelated and have changeable meanings in various environments,

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Figure 2. A Hopeful Look at the Surf

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Figure 3. The Marina

Provincetown, Mass., with its windmills and fish-drying tables; from an old woodcut

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Figure 4. An Early Example of Coastal Zone Use.

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Figure 3. Boca Ciega Bay near St. Petersburg, Florida, showing land development for housing.
The upper photograph shows the Bay in 1949. The lower photograph shows the same area
in 1965. Ecologists claim that excessive development can destroy the biological productivity
of an estuary. (Bureau of Commercial Fisheries photo by A irflite, St. Petersburg)

Figure 5. Land Development is a Dominant Feature of Coastal Zone Development.

we are obligated to think of the environment in terms of biological

change, as environmental protection. is presently a basis for much

dialogue and sometimes controversy. To do this we have chosen an old

concept and adapted it to identify the relationships among biological-

communities that may be changed when man or nature modifies the coastal

environment. The chosen term is BIOTOPE, which is defined in Webster's

as a region uniform in environmental,conditions and in populations of

animals and plants for which it is the habitat. Although the biological

environment may appear to the layman as either diverse or uniform

without pattern, there are recognizable biotic assemblages that have

some degree of relationship in their composition. Such recognizable

assemblages may cover wide areas, such as the extensive turtle grass

flats, or may be discrete small units, such as an oyster reef. Thus we

have adapted the term BIOTOPE to identify such assemblages and initially

suggest the following 18 examples listed in Table 1. Thirteen of them

plus an overview are illustrated-.

Estuarine inventories of plants and animals in the Gulf are not

difficult, and many are on hand in a variety of manuscripts, monographs

and check lists. However, often the inventories either concern specialized

groups of organisms for specific localities, or long lists of scientific

names.

If the concept of the biotope is to be used to describe common,

recognizable Texas Gulf coast communities, then we can use these

descriptions to demonstrate the results of changes. For example, if one

plans to dredge a grass flat to produce a spoil bank and a channel, the

Biotopes of these three areas can be compared to allow the decision maker

to evaluate how the change may affect the area involved. Because the

decision maker is not always scientifically oriented we have elected

.to describe the Biotope by artists' renditions accompanied with lists

of common and scientific names of major species of plants and animals

and a description of the relative productivity of the major organisms

in the area.

To make use of the Biotope concept, we must set some initial guide-

lines., As most communities are dependent on the physical and chemical

features of the coastal zone@ we can assume that some average conditions

exi,st, with the recognition that natural forces such as excessive rainfall

or storms may momentarily change these conditions and thus may change

the assemblage of living organisms. Pigure 6 illustrates the effect

of tidal movement in a lagoon as related to current flow and suspended

matter, and Pigure 7 gives the comparative production rates of carbon

or organic matter in transit from the coastal zone. The average rates

are in tons of organic carbon per year and show how productive the

estuary is. They also suggest the estuary's tremendous role as a food

(i.e. energy) source for coastal and offshore biota such as those that

form the commercial fishery.

We recognize the impossibility of listing and illustrating all the

diverse living organisms from unicellular forms to. large mammals in any

Biotope. However there are identifying assemblages of organisms that

can be used to show the biological balance of any specific Biotope.

Because of the migratory habits and seasonal life cycles of many coastal

zone species, we must integrate such data to show the dominant groups

for the major part of the year. We have provided in the following pages

a brief description of the 18 Biotopes in preliminary form. Artists'

renditions are @included. Modifications will be solicited by environmental

scientists and other biologists who are experts on the Gulf.

Table 1

BIOTOPES OF THE TEXAS COASTAL ZONE

Open Beach and Shelf
Dune and Barrier Flat
Spoil Bank
Jetty and Bulkhead
Oyster Reef
Thalassia (grass flat)
Spartina (salt water marsh)
Juncus (fresh water marsh)
Mud Flat
Sand Flat
Blue-Green Algal Flat
*Hypersaline
*River Mouth
Bay Planktonic
*Channel
*Prairie Grassland
*Upland Deciduous Forest
River Floodplain Forest

*These Biotopes have not been illustrated.

STATION. A
8-18-1962
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60- 50
CURRENT
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SUSPENDEDIO 1.0 10.0 0.3
MATTER 0.5 0'0 0.5 1.0
Mg/I 26- 10
500 00 5.0
30-

hours
5 6 7 8 9 10 11 12 13 14 15 16 17 18 19
Simultaneous measurements of current velocity, tide level and susp-
ended sediment in Guerrero Negro Lagoon, Baja California, Mexico (After
Postma, 1965).

Figure 6

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WPEN OCEAN.
DESERT DRY MOIST AGRICULTURE ESTUARINE COASTAL
AGRICULTURE
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ATURE

Comparative production rates among terrestrial and aquatic systems. Taken from Man In ThO UvIng EnvIronment.

Figure 7

The Biotope concept has been planned to augment the land use maps

developed by the Bureau of Economic Geology. They may be superimposed

to strengthen environmental evaluation by further identification of

resource development units. We should like to build into the Biotope

concept not only the description of the environmental unit but the

recognition that man?s changes may in some instances be advantagegus is

well as disastrous, while in other areas, change with the proper planning

may allow development and preservation of some aspects of the natural

environment to coexist.

Figure 8 is a chart that gives examples of the spatial distribution

of the Biotopes in Corpus Christi, Nueces, and Aransas Bays. This

Figure@ like Figure 1. depicts a representative Texas estuarine environment.

Two biotopes@ the upland deciduous forest and the floodplain forest., are

not indicated on Table 2 because this chart does not include any upland

areas.

The Biotope originals are in water color 18 by 24 inches in size.

The individual species of organisms are scientifically correct in form,

location and color. The artist concept allowed the'licence of grouping

in one picture@ the representative organisms,whereas@ at'any one part of

a biotopein nature@ some species may be absent. The scientific and

common names are given in separate listing and in the text. Approximately

350 references were used to document both the illustrations and the text.

Representative references are provided in this report. In all illustrations

the individual organisms were sketched in the field or drawn from collected

specimens.

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Figure 8. Schematic of Biotopes for Texas Coastal Zone

SYSTEM OF BIOTOPES

We have attempted to show'a hypothetical bay system by the Artists

rendition.Figure 8. This illustration contains most of the typical

biotopes presented in the following pages numbered in order from Gulf

to land. This illustration is designed to show the relationships between

the biotopes. While it does give a generalized overview, an inspection

of the natural environments shows that in many areas of less than one

acre that while one biotope may predominate other biotopes may be present

in discrete patches. We do not propose to go into such intricate detail

here but to show the relationships of the biotopes so that the information

can be used to describe actual field situations in the bay systems and

estuaries of the Texas Gulf Coast.

1. Open Beach and Shelf
2. Jetty and Bulkhead
3. Dune and Barrier Flat
4. Channel
5. Blue-green Algal Flat
6. Mud Plat
7. Spartina Salt Water Marsh
8. Spoil Bank
9. Sand Plat
10. Bay Planktonic
11. Oyster Reef
12. Fresh Water Marsh
13. River Floodplain Forest

DESCRIPTIONS OF INDIVIDUAL BIOTOPES

The various Biotopes given in Table 1 are individually described

in the following pages.

OPEN BEACH AND SHELF

The open beach biotope (Fig. 9) extends from the upper tidal margin

of the exposed coast to the edge of the continental shelf. The bottom

profile gently slopes away from the coast at about 8 feet per mile. Next

to the surf zone 2 to 3 underwater bars parallel the coast. The inshore

area is characterized by variable wave action, fairly strong tidally

influenced alongshore currents and a sandy bottom. The water is usually

.well mixed thermally and well oxygenated. Offshore, the wave action

subsides, currents are more stable in direction, and the bottom varies

between sand, mud@and shell with occasional reefs. There may be

stratification of temperature and oxygen levels in the deeper areas.

The economic and recreational importance of this area is well known.

The commercially important penaeid shrimp spend much of their life cycles

in this biotope. The highly desirable sports fish, tarpon, red snapper,

several species of trout@ as well as redfish, croaker, flounder) and

drum are found within or moving through the biotope. Other recreational

activities include swimming, sailing and camping.

Due to the rigors of the inshore environment, the fauna of the open

beach divide between burrowing and strongly swimming organisms. Among

the crustacean burrowers are found the mole crab., Emerita talpoida (19),

the ghost shrimp., Callianassa islagrande (20), and the mantis shrimp,

Squilla empusa (44). The swimming crabs, Callinectes danae and C. sapidus

(27) are often found in the inshore area. Copepods of the genus Callanus

(2) are found in the wave wash and interstitially in the sand, as well

as elsewhere in the water column. The coquina. clam, Donax variabilis

(17) 18) and the olive shell) Oliva sayana (24), are found from the

upper surf zone into deeper waters. Also represented from the area of

surf action are the sea pansy, Renilla renilla (37), the sand dollar

Mellita quinquiesperforata (34, 35) and the stingray Dasyatis americana

(33). With the exception of C. danae, all of the above are pictured in

Fig. 9.

Common offshore bottom dwellers pictured in Fig. 9 include the

whip coral@ Leptogorgia setacea (45), the pen shell, Atrina serrata (43),

starfish of the genus Astropecten (50), the electric ray, Narcine

brasiliensis (36)., the cow-nosed ray, Rhinoptera bonasus (51), the flounder,

Paralichthys lethostigma (38), and the brown shrimp) Penaeus aztecus (52).

Not shown are the white shrimp., Penaeus setiferus and the pink shrimp,

P. duorarum.

. Depicted from the water column are the diatoms Rhizosolenia sp. (5)

and Coscinodiscus radiatus (7), the dinoflagellateg Ceratium fusus (4)

and C. hipos (6) and an example of a typical foraminiferan (3). These

are only a small selection of the multitudes of microscopic plants and

animals found in this area.

The floating Sargassum community is also found along the coast.

Shown are details and habit of Sargassum sp. (9, 10) with some of the

specialized residents of these drifting brown algal masses. These

animals include the satgassum pipefish) Sygnathus pelagicus (8), the

sargassum crab Portunus qibbesii (12), the sargassum fish, Histrio histrio

(14), and the sargassum shrimp2 Leander tenuicornis (15). Along with

the sargasso.weed, another important drifting organism2 especially to

those who wish to use the beaches for swimming)is the Portuguese

Man O'War., Physalia physalia (41).

Finally2 there are the actively swimming forms that move within

this biotope and through.the inlets into other b iotopes. Those illustrated

include the squid Loligo brevis (39), the stripped mullet., Mugil cephalus

(25), the gafftopsail catfish, Bagre marinus (26), spotted sea trout.,

Cynoscion nebulosis (30), sheepshead,, Archosargus probatocephalus (31),

the eight-fingered threadfin, Polydactylus octonemus (32), golden croaker,

Micropogon undulatus (40), pompano, Trachynotus carolinus*(42), spot,

Leiostomus xanthurus (48), redfish Sciaenops ocellata (49), and black-

tipped shark, Carcharhinus limbatus* (46). Not shown in Fig. 9, but

important and common in the biotope are sea catfish Galeichthys felis*,

king mackeral Scomberomorus cavalla, tarpon Megalops atlanticus red,

snapper butjanus aya2 salt drum, Stellifer lanceolatus*, bumper.,

Chloroscombrus* chrysurus*, white mullet, Mugil curema, moonfish, Vomer

setapinnis, bluefish, Pomatomus saltatrix, pigfish, Orthopristis

chrysopterus) silver sea trout., Cynoscion nothus, stargazer, Astroscopus

y-graecum, pinfish) Lagodon rhomboides, king whiting, Menticurrhus

americanus* menhaden, Brevoortia patronis , leatherjacket, Oligoplites

saurus*, anchovy, Anchoa mitchelli diaphana, silver perch, Bairdiella

chrysura, rough silversides, Membras martinica vagrans, sand trout,

Cynoscion arenariusand spadefish Chaetodipterus faber.

*Asterisk indicates dominant species.

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Figur e 9. Open. Beach and Shelf

OPEN BEACH

1. Megalops larva of Callinectes sapidus - Blue crab
2. Calanus sp. - Copepod
3. Foram iniferan
4. Ceratium fusus - Dinoflagellate
5. Rhizosolenia sp. - Diatom
6. Ceratium hipos - Dinoflagellate
7. Coscinodiscus radiatus - Diatom
8. Sygn thus Delacricus - Sargassum pipefish
9. sargassum float
10. Sargassum leaf
11. Epizoic bryozoan
12. Portunas gibbesii - Sargassum crab
13. Epizoic bryozoan
14. Histrio histrio - Sargassum fish
15. Leander tenuicornis - Sargassum shrimp
16. Portunas cribbesii (imm). - Sargassum crab
17. Donax variabilis - Coquina
18. Donax variabilis - Coquina
19. Emerita talpoida - Mole crab
20. Callianossa islagrande - Ghost shrimp
21. C. islagrande burrow
22. Larus atricilla Laughing gull
23. Emerita talDoida Mole crab
24. Oliva a ana oIive shell
2S. Mugil cephalus Striped mullet
26. Bagre marinus Gafftopsail catfish
27. Callinectes sapidus - Blue crab
28. Astropecten sp. - Starfish
29. Astropecten sp. - Starfish
30. Cynoscion nebulosus - Spotted seatrout
31. Archosargus probatocephalus - Sheepshead
32. Polvdactylus octonemus - Threadfin
33. Dasyatis americana - Stingray
34. Mellita quinuiesperforata - Dead sand dollar
35. Mellita Quinuiesperforata - Live sand dollar
36. Narcine brasiliensis - Electric ray
37. Renilla renilla - Sea pansy
38. Paralichthyes lethostigma - Flounder
39. Loligo brevis - Squid
40. Micropogon undulatus - Golden croaker
41. Physalia physalia - Portugese Man o'War
42. Trachinotus carolinus - Pompano
43. Atrina serrata - Pen shell
44. Squilla empusa - Mantis shrimp
45. Leptogorgia setacea - Whip coral
46. Carcharhinus limbatus - Black-tipped shark
47. Sargassum sp. - Sargasso weed
48. Leiostomus xanthurus - Spot
49. Sciaenops ocellata - Redfish
50. Astropecten sp. - Starfish
51. Rhinoptera bonasus - Cownosed ray
52. Penaeus aztecus - Shrimp

DUNE AND BARRIER FLAT

The barrier islands of the Texas coast are the result of depositional

and aeolian processes since the present sea level was established. They

cause the impoundment of the coastal lagoon system and offer protection

from major storms. The dunes which are created on the open shore may be

as high as forty feet above sea level., although they average between five

and fifteen feet. These dunes are usually vegetated, which allows for

accretion and allows them to remain intact and resist displacement by

wind. Behind these large dunes there are vegetated flats punctuated

by swales and freshwater potholes. Finally, along'the lagoon edgep there

is a series of smaller vegetated dunes.

It is in society's interest to maintain the dunes with dense

vegetation., as they form a natural barrier to storm surges. Additionallyp

the vegetation retards sand migration,, preventing them from covering

roads @ and dwellings. The permeable sands behind the dunes form

a fresh water aquifer which is a vital supply in some areas.

The number of species of plants found on the seaward face of the

dunes is small compared to the variety found on the flats. The major

sand trapping plant is the sea oat@ Uniola Paniculata (3). Other plants

found in clo,se association with the sea oats are the bitter panicum,

Panicum amarum (12), the morning glories, Ipomoea pes-capre (9) and

I. stolonifera (16), and beach tea@ Croton punctatus (8)@ as shown in

Fig. 10. Other species trapping sand in the foredune area are seashore

dropseed@ Sporobolus virginicus., sea purselane) Sesuvium portulacastrum

and beach ground cherry) Physalis viscosa. Occasionally found on the

dunes and barrier flats are sweet acacia, Acacia farnesiana) salt cedar,

Tamarix,gallical the introduced Tamarix aphylla, the Australian pine@

Casuarina e uisetifolia,, and willows of the genus Salix.

The grassy areas of the barrier flat support seacoast bluestem,

Andropogon scoparius littoralis (4), beach tea., Croton punctatus (8)

and sunflowers Helianthus annuus (17), as shown in Fig. 10, as well

asthe grasses, Spartina patens, Paspalum monostachyum, and Sporobolus

virginicus which are not pictured. Shoregrass, Monathachloe littoralis

(not shown) is the dominant grass bordering mudflat areas. Seasonal

dominants are the evening primrose, Oenothera durmmondii and whitestem

wild indigo, Baptisia laevicaulis in the spring, and western ragweed,

Ambrosia psilostchya camphorweed Heterotheca subaxillaris groundsel

Senecio spartioides and an indigo Indigofera mineata, in the fall.

Variations in vertical elevation influence the vegetation of the

barrier flat. Hummocks have relict stands of Uniola paniculata the

sea oat while swales and potholes may contain marshhay cordgrass
Spartina patens cattails, genus Typha and Drummond rattlebox, Sesbania

drummondii if they have water standing for long periods, or the salt-

worts Salicornia bigelovii and S. Perennis and seashore dropseed,

Sporobolus virginicus if they are subject to intermittent drying.

Dominant fauna shown for this biotope include the coyote Canis

latrans (2), kangaroo rat Dipodomysordii (18) western coachwhip snake,

Masticophis flagellum (7) and western diamondback rattlesnake, Crotalus

atrox (19). Other reptiles shown are the glass lizard, Ophisaurus

attenuatus (24) five-lined skink Eumeces fasciatus (25) keeled earless

lizard Holbrookia propingua (10), and Texas horned lizard, Phyrnosoma

cornutum (14). The ghost crab Ocypode quadqrata (6) is found on the seaward

face of the dunes and occasionally on the vegetated flats. The laughing

gull Larus atricilla (1) and the sanderling, Crocethia (13) are commonly

found. The dragonflies., genus Anax (15) the small black ant Monomorium

minimum (21), the grasshopper Schistocerea americana (22) and centipedes,

genus Scolopendra (11,23)@ are representative of the terrestrial arthropods.

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Figure 10. Dune and Barrier Flat

DUNE AND BARRIER PLAT

1. Larus atricilla Laughing gull
2. Canis latrans - Coyote
3. Uniola paniculata - Sea oats
4. And gon littoralis - Seashore bluestem.
5. Cenchrus incertus Sand bttrl%
6. Ocypode quadrata Ghost crab
7. Masticophis flaqellum testaceus - Western coachwhip
8. Croton punctatus - Beach tea
9. Ipomoea pes-caprae - Goatfoot morning glory
10. Holbrookia propinqua - I(eeled earless lizard
11. Scolopendra sp. Centipede
12. Panicum amarum Bitter panicum
13. Crocethia alba Sanderling
14. phrynosoma cornutum. - Texas-horned lizard
15. Anax iunius - Dragonfly
16. Ipomoea stolonifera - Morning glory
17. Helianthus annuus - Sunflower
18. Dipodomys ordii Kangaroo rat
19. Crotalus atrox Western diamondback rattlesnake
20. Helianthus sp. Sunflower
21. Monomorium minimum - Little black ant
22. Schistocerea americana - Grasshopper.
23. Scolopendra sp. - Centipede
24. Ophisaurus attenuatus - Glass lizard
25. Eumeces fasciatus 5-lined skink

SPOIL BANK

Spoil banks are composed of mud, sand and shell dredged from

several layers of sediments and deposited in mounds extending above

the water surface, often parallel to the channels created. These

islands vary in shape from circular to elongate with vertical elevations

of up to twenty feet. Eventually, these areas are colonized by the

organisms shown in Fig. 11.

The upper reaches are inhabited by several higher plants, among

them2 salt cedar, Tamarix gallica (1), honey mesquite, Prosopis juliflora

glandulosa (11), low prickly pear, Opuntia compressa (12), seashore

bluestem) Andropogon scopari s littoralis (2), Gulf cordgrass, Spartina.

spartinae (31), sea oats, Uniola 'paniculata (13),, and goatfoot morning

glory, Ipomoea pes-caprae (10),, as shown in Fig. 11. In the intermediate

areas@ those reached only by the highest tides,, are found sea p urselane,

Sesuvium portulacastrum (8). and marsh hay cordgrass, Spartina patens (6).

At the water's edge are found saltgrass@ Distichlis spicata (7), the

.woody glassworts, Salicornia virginica (4) and S. bigelovii (15) and

smooth cordgrass, Spartina alterniflora (17). Finally, the submerged

grasses. often found near the islands include2 turtle grass, Thalassia

testudinum (25), shoal'[email protected] wrightii(21). as shown in

Fig. 11, and sometimes widgeon grass) Ruppia maritima and Halophila

engelmannii.

Animals found ashore include numerous insects, ghost crabs,

fiddler crabs of the genus Uca, and hermit crabs, among them Clibinarius

vittatus (20) and Pagurus policharus. The hermit crabs are also found

in the adjacent waters,, along with blue crabs, Callinectes sapidus (29),

brown shrimp) Penaeus aztecus (27), oysters2 Crassostrea virginicus (30)2

as shown) and the clams Rangia cuneata and Mercenaria mercenaria.. The

fish depicted include sand trout, Cynoscion arenarius (23), golden

croaker, Micropogon undulatus (24). black drum, Pogonias cromis (26).

flounder., Paralichthys lethostigma (28), and spot, Leiostomus xanthurus

(not shown). These fish feed both in the open water and among the

grass beds.

Spoil banks offer good nesting and resting places for birds since

they are often above the tides, and vegetated, offering physical protection.

Common birds are the black skimmer) Rynchops nigra (5), and the white

pelican) Pelacanus erythrorhychos (16).

While this biotope is a relatively low producer) it has a yet
unexploited value to society as a rotreat.for fishermen, boaters,

picnickers and campers.

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Figure 11. Spoil. Bank

SPOIL BANK

1. Tamarix gallica Salt cedar
2. Andropogon scoparius littoralis - Seashore bluestem
3. Senecio sp. - Groundsel
4. Salicornia sp. - Glasswort
5. Rynchops nigra - Black skimmer
6. Spartina patens - Marshhay cordgrass
7. Distichlis spicata - Salt grass
8. Sesuvium portulacastrum - Sea purselane
9. Baptistia leucophaea - White stem wild indigo
10. Ipomoea pes-caprae - Goatfoot morning glory
11. Prosopis juliflora glandulosa - Honey mesquite
12. Opunita compressa - Low prickly pear
13. Uniola paniculata - Sea oats
14. Senecio sp. - Groundsel
15. Salicornia bigelovii - Saltwort
16. Pelecanus erythrorhynchos - White pelican
17. Spartina alterniflora - Smooth cordgrass
18.. Gallardia pulchella - Indian blanket
19. Spartina alterniflora Smooth cordgrass
20. Clibinarius vittatus Hermit crab
21. Diplanthera wrightii Shoalgrass
22. Diplanthera wrightii Shoalgrass (sprouts)
23. Cynoscion arenarius Sand trout
24. Micropogon undulatus Croaker
2S. Thallassia testudinum Turtle grass
26. Pogonias cromis - Black drum
27, Penaeus aztecus - Brown shrimp
28. Paralichthyes lethostigma - Flounder
29. Callinectes sapidus Blue crab
30. Crassotrea virginica American oyster
31. Spartina spartinae Gulf cordgrass
32. Uniola vaniculata Sea oats

JETTY AND BULKHEAD

Jetties and bulkheads are man-made structures of rock, shell,

concrete2 wood and steel, placed to restrict sedimentation in channels

or to provide docking areas. As a result these structures are in areas

where there is variable current energy and offer a surface and protection
to a wide variety of organisms. Salinity does control the population@.
Therefore our illustration depicts organisms adapted to salinities above

15 ppt. Thus, most of the forms which inhabit them are either adapted

to clinging) physically fixed to the substrate or free swimming. The

flora are predominantly brown2 red and green algae, with some blue-green

algae in the splash zone. The fauna represent a wide variety of animals,

The d6minent green algae pictured in Fig. 12 are of the genera

Ulva (14), Enteromorpha (15), Cladophora. (13) and Chaetomorpha (8). The

dominant brown alga is of the genus Padina (22) with some Dictyota (18).

The dominant red alga shown is of the genus Agardhiella (21), with

Hypnea (20), Gelidium (9)) Giffordia (16), Bryocladia (6). Gracilaria

(27), and Rhodomenia (24). All of these forms are firmly attached to

the rocks and are highly flexible in order to withstand the rigors found

on the jetties.

The attached fauria shown are sponges@ coelenterates2 two molluscs

and a crustacean. The sponges are of the genera Microciona (25,26) and

Haliciona (38). The coelenterates are the anemone2 Bunodosoma cavernata

(23), sea whip,, Leptogorgia setacea (36), and the remains of an alcyonarian,
Oculina sp 4? a sessile anthozoan. The oyster2 Crassostrea virginica (10).
mussel., Modiolus americani4 and barnacles of the genus Balanus (1)
complete the range of attached animals shown from this biotope.

Motile forms which cling to the substrate include the gastropods

Thais haemostoma (41) and Littorina irrorata (5), the rock crab, Menippe

mercenaria (35), hermit carb, Clibinarius vittatus (28) the sea urchin,
Arbacia punctulata (32) and the isopod wharf roach Lygia exotica (4).

The crested blenny, Hypleurochilus geminatus (11), lives in the sheltered

cracks of the jetties.

Strongly swimming forms shown include thespotted jewfish Promicrops
itaiara, (17) sheepshead, archosargus probatocephalus (30), mullet, mugil
cephalus (29), blue crab, callinectes sapidus (12), and another portunnuid
crab ovalipes ocelltus (19).

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Figure 12. Jetty and Bulkhead

JETTY AND BULKHEAD

1. Balanus sp. Barnacle
2. Thais haemostoma - Florida rock shell
3. Enteromorpha flexosa - Green alga
.4. Lygia exotica - Wharf roach
5. Littorina irrorata - Periwinkle
6. Bryocladia cuspelata - Red alga
7. Ulva lactuca - Green alga
8. Chaetomorpha sp. - Green alga
9. Gelidium sp. - Red alga
10. Crassostrea virginica - American oyster
11. Hypleurochilus geminatus - Crested blenny
12. Callinectes sapidus Blue crab
13. Cladophora vaqabund-a Green alga
14. Ulva fasciolata - Green alga
15. Enteromorpha linqulata - Green alga
16. Giffordia sp. - Red aiga
17. Promicrops itaiara - Spotted jewfish
18. Dictyota dichotoma - Brown alga
19. Ovalipes ocellatus - Swimming crab
20. Hypnea musiciformis - Red alga
21. Agardhiella tenera - Red alga
22.' Padina vickerisae - Brown alga
23. Bunodosoma cavernata - Anemone
24. Rhodomenia palmata - Red alga
25. Microciona sp. - Sponge
26. Microciona, sp. - Sponge
27. Gracilaria prolifera - Red alga
28. Clibinarius vittatus - Hermit crab
29. Mugil ceDhalus - Striped mullet
30. Archosargus probatocepbalus Sheepshead
31. White sponge
32. Arbacia punctulata - Urchin
33. Hydroid
34. Yellow sponge
35. Menippe mercenaria - Rock crab
36. Leptogorgia setacea - Sea whip (octocoral)
37. Oculina sp. - Hard'coral
38. Haliciona sp. Pink sponge
39. Microciona sp, Sponge
40. Clibinarius vittatus - Hermit carb
41. Thais haemostoma - Florida rock shell
42. Modiolus sp. Mussel and attachments
43. Lygia exotica Wharf roach
44. Blennius cristatus - Rock' blenny
45. Microciona sp. - Orange sponge
46, Hydroid
47. Cladophora vagabunda - Green alga
48. Ulva flexosa - Green alga
49. Padina veckersae - Brown alga
50. Dictvota dichotoma, Brown alga
51, Bryodadia cuspelata Red alga

OYSTER REEF

Wherever currents of sufficient velocity to transport suspended

material are found in combination with solid substrates, sedentary filter

feeding animals tend to cluster. With time, the hard exoskeletons of

these organisms accumulate.into sizeable mounds and ridges. Such vertical

anomalies formed by the American oyster@ Crassostrea virginica (3), and

associated organisms constitute the oyster reef biotope (Fig. 13). These

reefs occurin all the major Texas bays except Baffin Bay and Laguna

Madre, probably because of a requirement of lower salinities. In

shallow waters@ the reef may form a low island with a fringe of live

oysters in the intertidal zone2 while in deeper waters, the reef may

form a shoal rising several feet from the bottom) with live oysters

covering its entire surface. Intertidal oysters will grow at higher

salinities than submerged oysters.

Typical associated reef plants in the Texas coastal area are sea

lettuce@ Ulva lactuca (1)2 the red alga Hypnea musiformis (9), an d the

green algal genus Cladophora. (8), as shown in Fig. 13. Other sessile

animals shown in the reef setting are barnacles@ genus Balanus (2)

anemones2 Bunodosoma cavernata (4), various hydroids (25), mussels,

Modiolus. americana (10)@, and serpulid worms, genus Hydroides (21).

Organisms dependent on the shellfish for food include the Florida

rock shell, Thais haemostoma (6). a type of oyster drill and stone

crabs, Menippe mercenaria (15)@ starfish, Luidia clathatare (22). and

oyster crabs, Pinnotheres ostreum,(35). Burrowing forms include snapping

shrimp, Crangon heterochaelis (20), boring sponge) genus Clione (19),

mud crab, Panopeus herbstii (18). flat mud crab, Eurypanopeus depressus

(12). polychaete worms of the genus Polydora sp. (33) and the boring

.clam, Diplothyra smythi (34). The thiton, Ishnochiton papillosus (5),

grass shrimp, genus Paleomonetes-(16)@ brittle star, genus Ophioroides
(23)
(24) and the whelk@ Busycon contrarillmAare the predominant grazers.shown
for this biotope. Several small fish are found associated with the

reef@ among them skillet fish, Gobiesox strumosis (11), crested blenny.,-

Hypleurochilus geminatus (13), and gulf toadfish, Opsanus beta (26).

The black drum, Pogonias cromis (14). is known to fee d on oysters and

other shellfish.

When the reef is exposed,various birds such as white pelicans,

Pelecans erVthrorhynchos, great blue heron, Ardea herodias and laughing

gu112 Larus atricilla.use it as a resting place.

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Figure 13. Oyster Reef

OYSTER REEF

1. Ulva lactuca Sea lettuce
2. Balanus sp. Barnacle
3. Crassostrea virginica, Oyster
4. Bunodosoma cavernata Aneikolte
5. Ischnochiton Papillosus - Chiton
6. Thais haemostoma - Florida rock'shell
7. Thais h. eggs
8. Cladophora sp. - Green alga
9. Hypnea musiformis Red alga
10. Modiolus ameficana Mussel
11. Gobiesox strumosus Skillet fish
12. Eurypanopeus depressus - Flat mud crab
13. Hypleuro*chilus geminatus - Crested blenny
14. -Pogonias cromis - Black drum
15. Menippe mercenaria -@ Stone crab
16. Paleomontes sp. - Grass shrimp
17. Crangon heterochaelis - Snapping shrimp
18. Panopeus herbstii - Mud crab
19. Clione sp. - Boring sponge
20. Crangon heterochaelis - Snapping shrimp
21. Hydroides sp. - Serpulid worms
22. Luidia clathatare Starfish
23. Busycon.contrarium Whelk
24. Ophioroides sp. - Brittle star
25. Hydroid
26. Opsanus beta - Gulf toadfish
27. Oyster egg undergoing fertilization
28. beginning of shell formation Stages in the development
29. Last free-swimming stage of Crassostrea, virginica
30. Spat 5-6 hours after settling
31. Adult Crassostrea virginica,
32. Crassostrea virginica - American oyster
33. Polydora sp. - Polychaete
34. Diplothyra smythi - Boring clam
35. Pinnotheres ostreum. Oyster crab

THALASSIA GRASSFLAT

This extensive and productive biot6pe is,.characteristically composed

of moderate to dense growths of turtle grass) Thalassia testudinum (22),

shoal grass) Diplanthera wrightii (20). Halophila engelmannii (19) and

widgeon grass, Ruppia maritima, as shown in Fig..14 (R. maritima not shown).

The distribution is usually in one to five feet.of water along the margins

and throughout baysand lagoons. Depths are controlled by turbidity of

the water which limits light penetration. Combined with the heavy growths

of attached plants and animals, the biomass represented by the grass flats

is large. When the plants die back in autumn, the leaves and stems break

.off and are distributed among the other biotopes where the material)

whether grazed or decomposed) makes significant contributions to the

food chain. The growth offers protection and is generally thought of

as the major nursery area for the young of many species of fish and

crustaceans.

The grass acts as a surface for many invertebrates and microalgae

such as diatoms. This adds to the productivity of the area. The

sediments2 because of the quieting action of the grasses are generally

soft and anaerobic due to entrapment of organic matter.

Due to the seasorial and diurnal fluctuations in temperature, and

migratory habits, few highly motile animals are found in this biotope

on a permanent basis. Among the sedentar-y species found are large

numbers of bryozoans (not shown), hydroidsAand serpulid worms of the

genus Spirorbus (5) (6). These organisms share the leaves and stems

with equally large numbers of sessile diatoms such,as Cocconesis sp.

(not shown).

Many of the motile forms in this biotope are omnivores which

function both as scavengers and grazers. These include the horn shell@

Cerithidea turrita (8), olive nerite, Neritina reclivata (9) and a small
gastropod, Odostomia gibbosa (15), as shown@ as well as Melampus sp. and,,,
Modulus sp., among the gastropods. Crustacean members shown for this

group are the grass shrimp', Paleomonetes vulgaris (7), hermit crab,,

Clibinarius; vittatus (16), mud crab, Neopanope texana (17), blue crab)

Callinectes savidus (18), a crab known as Rhitropanopeus harrissi (24),

the brown and pink shrimps, Penaeus aztecus (2) and P. duorarum (27), as

well as the white shrimp@ Penaeus setiferus,2 which is not shown. The

shrimp appear in the grass flats as early larval stages and use the cover

and food of this biotope as a nursery, migrating offshore to spawn upon

maturity. Many larval fish species develop in the protection of-this

biotope) as well. Final members of this group) as shown) are the sea

cucumber, genus Thyone (13), the brittle star, genus Ophiothrix (14),

And the mud worm Phascolo6oma gouldii (28).

The burrowing forms of this biotope are the razor clam@ Ensis minor

(23), Venus clam2 Chione cancellata (25) and Lucina clam, Phacoides

pectinatus (26), as shown@ as well as those of the genera Tellina, Tagelus

and Laevicardium.

Many fish frequent the grass flats. These include pinfish, Lagodon

rhomboides (1), spotted sea trout, Cynoscion nebulosus (3), tidewater

silversides, Menidia beryllina (11), redfish.,Sciabno-p ocellatus. (12),

as well as golden croaker, Micropogon undulatus, mullets, Mugil cephalus

and M. curema, and menhaden, Brevoortia patronis.

Several algae are represented from this biotope in addition tothose

mentioned as epiphytes. These include the large red alga Gracilaria (10),

the diatoms nitzchia (30) and cymbella (31), the dinoflagellate, ceratium
(29), the euglenoid dunaliella (33), the blue-green oscillatoria (32) and
the colonial green alga, microcystis (34, 35).

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Figure 14. Thalassia (grass flat)

THALASSIA GRASSPLAT

1. Lagodon rhomboides - Pinfish
2. Penaeus aztecus - Brown shrimp
3.. Cynoscion nebulosus. - Spotted sea trout
4. Hydrozoan
5. Spir(:Lbus sp. - Serpulid worm
6. SpirMus sp. - Serpulid worm
7. Paleomonetes vulgaris - Grass shrimp
8. Cerithidea turrita - Horn shell
9. Neritina reclivata - Olive nerite
10. Gracilaria sp. - Red alga
11. Menidia bervllina - Tidewater silverside
12. Sciaenops ocellatus - Juvenile.redfish
13. Thyone sp. - Sea cucumber -
14. Ophiothrix sp. - Brittle star
15. Odostomia gibbosa - Small gastropod
16. Clibinarius vittatus - Hermit crab
17. Neo anope lexana - Mud crab
18. Callinectes sapidus Blue crab
19. Halophila engelmanni Sea grass
20. Diplanthera wrightii Shoal grass
21. Phacoides vectinatus Lucina clam
22. Thalassia testudinum Turtle grass
23. Ensis minor - Razor clam
24. Rhitropanopeus harrissi - Burrowing crab
25. Chione cancellata - Venus clam
26. Phacoides Pectinatus - Lucina clam
27. Penaeus duorarum - Pink shrimp
28. Phascoiosoma gouldii - Mud worm
29. Ceratium sp. - Dinoflagellate
30. Nitzchia sp. - Diatom
31. Cymbell sp. - Diatom
32. Oscillatoria sp. - Blue green alga
33. Dunaliella paupera - Saline euglenoid
'34.. Microcystis sp. (colony) - Green alga
35. Microcystis sp. (individual) Green algae

SPARTINA (SALT WATER MARSH)

This biotope is subjected to intermittent inundation due to tidal

action. Fluctuations in temperature) salinity, water depth and sediment

have exerted a strong selective effect) limiting the numbers of organismJ,

found. The dominant grass in this biotope is smooth cordgrassp Spartina

alterniflora (11). Like the grass flat biotope, the plant material

produced in this biotope, mostly .2. alterniflora (11), makes a large

contribution to the food chain of the estuarine ecosystem. The sediments

may range from fine anaerobic silt to sand or shell. Occasionally oyster

reefs are found in this biotope. The productivity of the area is high

and the grass blades offer protection and attachment for many organisms

below and above water. The decayed grass adds to the fertility of the

surrounding water areas.

Other common plants shown in Fig. 15 for this biotope are the woody

glasswort, Salicornia bigelovii (8)2 and saltwort@ Batis maritima (17),

in the lower areas, and beach tea., Croton punctatus (15), saltgrass

Distichlis spicata (22), sea purselane, Sesuvium portulacastrum (16) and

black mangrove, Avicennia -germinans (61 19., 21)., in the higher, better

drained areas.

There are numerods birds that nest or feed in this biotope. Those

shown are the great blue heron,. Ardea herodias (1), green heron@ Butorides

virescens (2), blue winged teal, Anas discors (3),'roseate spoonbill,

Ajaia ajaia (4), common egret2 Casmerodius albus (5), white ibis@ Eudocimus

albus (7), clapper rail) Rallus longirostris (12) and longbilled marsh

wren., TelmatodVtes palustris (14).

Grazing and scavenging are accomplished by a variety of animals

Those shown include the hermit crabs3, Pagurus (13). the fiddler crab,

Uca pugnax (18) and the periwinkle@ Littorina irrorata (20). The raccoon,

Procyon lotor (9) is a common visitor, feeding on such shellfish as

mussels) cockles and snails. In the substrate there are untold numbers

of annelid and nematode'worms, soil arthropods, and bacteria which

contribute to final decomposition of detritus.

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Figure 15. Spartina (salt water marsh)

SPARTINA SALT MARSH

1. Ardea herodias - Great blue heron
2. Butoridds virescens - Green heron
3. Anas discors Blue winged teal
4., Ajaia ajaja Roseate spoonbill
5. Casmerodius albus - Common egret
6. Avicennia germinans - Black mangrove
7. Eudocimus albus - White ibis
8. Salicornia bigelovii - Glasswort
9. Procyon lotor - Racoon.
10. Distichlis spicata - Saltgrass
11. Spartina al7terniflora - Smooth cordgrass
12. Rallus lonairostris - Clapper rail
13. Pagurus sp. - Hermit crab
14. Telmatodytes palustris - Longbilled marsh wren
15. Croton punctatus - Beach tea
16. Sesu ium portulacastrum - Sea purselane
17. Batis maritima - Salt wort
18. Uca pugnax - Fiddler crab
19. @-vicenfiia germinans - Black mangrove
20. Littorina irrorata - Periwinkle
21. Avicennia germinans - Black mangrove
22. Distichlis spicata - Saltgrass

JUNCUS (FRESH WATER MARSH)

The fresh water marsh biotope is found in permanent fresh water

ponding or river areas which are maintained by permanently high water

table levels or high rainfall. The dominant vegetation are reeds, genus

Juncus (4), and rushes, genus Scirpus (5,12,20) a8 shown in Fig. 16.

Also found here are the cordgrasses, Spartina, alterniflora and S. patens

(14) as well as cattails, genus Typha (11,,21)., and bamboo briars@ Smilax

sp. (10). In areas where there is a salinity gradient, the community

composition changes along the gradient into a Spartina dominated salt

marsh. The sediments are usually soft mud, often anaerobic due to high

organic content. The boundary area is often characterized by the

submerged grass Ruppia maritima (not shown).

The large amounts of plant material produced'annually (estimated

at 20,000 lb. per acre, E. P. Odum) 1959) provide food and nesting areas

for many waterfowl. Among these arethe Canada goose, Branta canadensis

(1), green heron, Butorides virescens (2), coot., Fulica americana (8),

and wood ibis, MVcteria americana (9). The crustaceans are also

represented in the fresh water marsh, with crayfish, Procambarus clarki

(7,17) feeding on the abundant detritus produced. The sheepshead minnow,

Cyprinod2n varie us (18)@ also feeds on this material, Common

terrestrial vertebrate inhabitants are the western diamondback rattlesnake)

Crotalus atrox (15). the cottonmouth2 Aqkistrodon piscavoris (19), the

opossum2 Didelphus mesamericana (13) and the norway rat, Rattus norvegicus

(6).
With the flushing action due to high tides and heavy runoff, mdch

of the detrital material and bacterial decomposition products are

introduced into the economy of the bay. Along drainage channels where

there is an intertidal interface, the fiddler crabj Rca pugnax (16).,

predominates along the banks@ and the clams., Mercenaria mercenaria and

Taegelus divisus (not shown)@ the channel bottoms. Also found, but not

shown@ is the marsh periwinkleg Littorina irrorata, which feeds on the

grasses.

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Figure 16. Juncus (fresh water marsh)

JUNCUS FRESH WATER MARSH

1. Branta canadensis - Canadian geese
2. Butorides virescens - Green heron
3. Spartina alterniflora - Smooth cordgrass
4. Juncus sp. - Reed
5. Scirpus sp. - Bullrush
.6. Rattus norVegicus - Norway rat
7. Procambarus burrow
8. Fulica americana - Coot
9. mycteria americana - Wood ibis
10. Smilax sp. - Bamboo briar
11. Typha domingensis - Cattails
12. Scirp.@,us sp. - Bullrush
13. Didelphis mesamericana - Opossum and young
14. Spartina patens Marsh hay cordgrass
15. Crotalus atrox Western diamondback rattlesnake
16. Uca Pugnax - Fiddler crab
17 Procambarus clarki - Crayfish
18. Cyprinodon variegatus Sheepshead minnow
Aqkistrodon piscavoris Cottonmouth snake
20. Scirpus sp. - Bullrush
21. Typha domingensis - Cattail
22. Sporobolus virginicus Seashore. dropseed

MUD FLAT

Mud flats are extensive regions in the highest backwaters of the

estuarine system. They consist of mobile fine silt that is quite drained$

with some. ponding. This does not allow larger organisms to stabilize

the substrate. Consequently most of the biota are interstitial. This

biotope grades into blue-green algal mats in areas subject to

wind tides and frequent ponding. In general mud flats are hydrated

enough to be anaerobic at depths of a few centimeters. While they do

not appear to be permanently inhabited by larger organisms, the interstitial

organisms consisting of both plants and animals are quite productive.

Where plants do colonize, mounds of stabilized sediment stand above the

mud flat.

The flats are often bounded by banks which are covered with salt-

grass., Distichlis spicata (1), and glassworts, Salicornia bigelovii and

S. Rerennis (29 8, 11), as shown in Fig. 17.

There are huge numbers of small organisms living both on and in
the mud. Due to the numbers, the productivity"is high although the area

may appear barren. These include aerobic.bacteria (16), which may reach

densities as high as 10,000,000 per gram of mud, diatoms2 Navicula (12)

and Coscinodiscus sp. (15), numerous protozoans2 such as Euplotes (13).,

and Euglena sp. (14), dinoflagellatess nematodes2 copepods2 amphipods,

ostracods, as well as anaerobic bacteria. Other infaunal organisms

include the gem clam2 Gemma. gemma, (17). polychaete, Amphitrite-(18)

and the clam Tagelus sp. Organisms which may be found living on firmer

bank areas are oysters2 Crassostrea virginica (7) and fiddler crabs2

Uca Pugnax (9).

Many birds are common visitors. Those shown are Black necked stilt,

Himantopus mexicanus (3,4), western sandpiper, Ereunetes mauri (5),

marbled goodwit) Limosa,fedoa, and the dowitcher@ Limno dromus scolopaceus

(10).

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Figure 17. Mud Flat

MUD FLAT

1. Distichlis spicata Salt grass
2. Salicornia sp. - Glasswort
3. Himantopus mexicanus'(female) - Black necked stilt
4. Himantopus mexicanus (male) - Black necked stilt
5. Ereunetes mauri - Western sandpiper
6. Limosa fedoa - Marbled godwit
7. Crassostrea virginica Oyster
8. Salicornia bigelovii Glasswort
9. Uca pugnax - Fiddler crab
10. Limnodromus scolopaceus - Dowitcher
11. Salicornia perennis - Glasswort
12. Navicula sp. - Pennate diatom
13. Eup otes sp. - Protozoan
14. Euglena sp. - Green algae
15. Coscinodiscus sp. - Diatom
16. Aerobic bacterium
17. Gemma. gemma - Gem clam
18. Amphitrite sp. Polychaete

SAND FLAT

This biotope is characterized as a flat area sometimes inundated

by wind tides. The bottom consists of unstable sand. The rigors of

this substrate preclude organic sediments as well as attached plants

or animals. Low energy currents and winds are responsible for moving

the sand from place to place. As in the mud flats, the interstitial

spaces in the sand offer a habitat for an extensive microflora.

Evaporative processes replenish nutrients from deeper layers' by capillary

action. While not appearing to be productive, this biotope produces

considerable biomass.

The banks are often bounded by salt grass,, 'Dist ichlis spicata (11)

and glassworts., Salicornia bigelovii and S. perennis (8,12). as shown

in Fig. 18. Also found on the banks are fiddler crabs,, Uca pugnax (3,7)..

Bottom dwellers include razor clams, Ensis minor (13), occasional oysters2

Crassostrea virginica (9), protochordates2 Saccoglossus sp. (23), the

tube-building worm, Clymenella torquata (22)2 nematode worms (24),.the

protozoan genera Amoeba (19) and Euplotes (17), the diatom Navicula

punctigera (18). the blue-green algal genus Chroococcus (20), and various

sulfur bacteria such as Desulfovibrio (16) and Beggiatoa (21).

Common birds are'the greater yellowlegs., Totanus melanoleucus (1),"

caspian tern, Hydropogone caspia, (2). sanderling Crocethia alba (4),

avocet@ Recurvirostra americana (5)@ ruddy turnstone2 Arenaria. interpres

(6), semipalmated plover., Charadrius semipalmatus .(l) and the oyster

catcher, Haematopus Palliatus (14).

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Figure 18. Sand Flat

SAND PLAT

1. Totanus melanoleucus - Greater yellowlegs
2. Hydroprogne caspia - Caspian tern
3. Uca yugnax - Fiddler crab
4. Crocethia alba - Sanderling
5. Recurvirostra-americana - Avocet
6. Arenaria interpres - Ruddy turnstone
.7. Uca pugnax - Fiddler crab
8. Salicornia bigelovii Glasswort
9. Crassostrea virginica Oyster
10. Charadrius semipalmatus - Semipalmated plover
11. Distichlis spicata - Salt grass
12. Salicornia perennis - Glasswort
13. Ensis minor - Razor clam
14. Haematopus palliatus - Oyster catcher
15. Sand grains, microscopic view
16. Desulfovibrio desulfuricans - Sulfur bacterium
17. Eup otes sp. - Protozoan
18. Navicula vunctiqera - Diatom
19. Amoeba sp. - Protozoan
20. Chroococcus sp. - Blue-green alga
21. Beggiatoa sp. - Sulfur bacterium
22. Clymenella torquata - Polychaete
23. Saccoglossus sp. Protochordate
24. Nematode

BLUE-GREEN ALGAL FLAT

Blue-green algal fl ats (Pig. 19) are common along the floodplains

adjacent to the estuaries and on marsh areas just above the tidal range

where they are occasionally innundated with fresh or brackish water.
The sediment.is normally fine sand or silt on'which the filamentous

blue-greens infiltrate to form a leathery mat.. The underlying sediment

is usually anaerobic. When these areas are covered by a wind tide, or

rain runoff, the photosynthetic activity produces gas bubbles@ which

cause large pieces of the algal mat to float on the water surface.' At

times of high tide these floating algal mats will wash into adjacent

waters. The algal mats also act as a wick during the almost continuous

wind. Thus the nutrient byproducts from the underlying sediments and.

water from the water table are drawn by capillary action to the algal

surface. This results in incrustations of halite and nutrients. These

nutrients act as fertilizer for the algal mat and at times when the

area is covered by wind tides or rainfall@ these salts are washed into

the adjacent waters, increasing their productivity.

The area may extend over many miles or be restricted to a small

shallow de@ression along the shore where conditions are right for the

algal growth. These aieas are quite productive2 extending into the

sediment for several millimeters and actively stabilize the sediments.

The algal mats contain a wide variety of microorganisms.

The major constituent of this mat is the blue-green alga Lyngbya

majuseula (8). Also found are the blue-greens Holopedia irregularis (9),

Nodularia sphaerocarpa (10) and N. tenuis (11), Oscillatoria limosa (12),

the diatoms Pleurosigma anqulatum (14)@ Navicula punctigera (15) and

N. diversistrata (16)) the green alga Chlorococcus (13)p the euglenoids

Chlamydomonas snowiae (17) and Eyramimonas tetrarhynchos (18). Bacterial

components@of the mat are Rhodospirillum fulvum (19), Rhodopseudomonas

palustris (20), Rhodomicrobium vannieli (21) and species of the genera

Beggiatoa (22) and Thiocapsa (23)@ and numerous others.

The banks of,this biotope are lined with saltgrass., Distichlis

spicata- (4, 28) and glasswort@ Salicornia perennis (3@ 29). Numerous

crustacean browsers feed on the algae, which are in turn fed upon by

cyprinodontid fish and blue crabs, Callinectes sapidus (5), during periods

of high water levels. There are also the snowy egret) Leucphovx thula (1)

and great blue heron, Ardea herodias (2).

Numerous nematods, diatoms and,protozoans grow both in and-below

the blue-green layer. The anaerobic sediments are rich in various

bacteria such as the desulforibrio and pseudomonads.

1 2

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BLUE-GREEN ALGAL MAT
1. LeucoT)ho'yx thula - Snowy egret
2. Ardea herodias - Great blue heron
3. Salicornia sp. - Glasswort
4. Distichlis spicata - Saltgrass
5. Callinectes sapidus - Blue crab
6. Floating algal mat - Mixed microflora,
7. Crassostrea virginica -'Oyster (dead)
8. Lyngbya majuseula - Blue-green alga
9. Holopedia irregularis Blue-green alga
10. Nodularia sphaerocarpa Blue-green alga
11. Nodularia tenuis - Blue-green alga
12. Oscillatoria limosa - Blue-green alga
13. Chlorococcus sp. - Blue-green alga
14. Pleurosigma angulatum - Diatom
15. Navicula punctigera - Diatom
16. Navicula diversistriata - Diatom
17. Chlamvdomonas snowiae - Euglenoid
18. PVramimonas tetrarhynchos - Euglenoid
19. Rhodospirillum, fulvum, - Sulfur bacterium
20. Rhodopsuedomonas palustris - Sulfur bacterium
21. Rhodomicrobium vannieli - Sulfur bacterium
22. Beg iatoa sp. - Sulfur bacterium
23. Thiocapsa sp. - Sulfur bacterium
24. Rod shaped
25. Short rods Various bacteria
.26. Coccoid
27. Spirilla
28. Distichlis spicata Saltgrass
29. Salicornia Perennis glasswort

HYPERSALINE

Where sea water flows into shallow lagoons in climates with more

evaporation than runoff, salinities rise and briny conditions develop.

Organisms living in this high salinity (hypersaline) biotope require

special adaptations to take up food and excrete e;kcess salt. Diversities

diminish and highly characteristic systems develop with a few species of

phytoplankton, zooplankton2 clams and fish in waters with salinities

above 50 O/oo. Examples of this biotope are Baffin Bay and the Laguna

Madre. High organic levels develop because of the generally poor

efficiency of the simple system in processing organic food chains.

On the landward side of hypersaline lagoons Iare extensive areas

known as pans and flats. These shallow, flat areas are important for

nutrient circulation and net transport of water. There is a significant

increase in salinity with increase in distance from the sea-lagoon

connection, with as much as a 25 to 40 O/oo difference between the upper

(landward) and lower (seaward) margins.

Due to the need for osmotic stress adaptation, the diversity of

organisms in hypersaline waters is low. The magnitude of the stress

involved is a function of the energy drains of adaptive work required

for the species to remain as a part of the particular system. Primary

producers are blue-green algae,, diatoms and other alga. In the Laguna

Madre-the vast underwater beds of Diplanthera and2 less significantly,

Thalassia. permit the development of more complex food webs based on the

higher primary productivity of the benthic systems.
Migrating populations of breeding fishes and associated invIertebrate

animals contribute to the balanced coupling of production with consumption.

Detritivores feeding on bottom organic matter include mullet (Mugil),

croaker (Micropogon), and shrimp (Penaeus). Detritivores feeding on

suspended organic material include the barnacle (Balanus)@ crabs

(Callinectes), and sea catfish (Galeichthys). Secondary consumers include

trout (Cynoscion), croaker (Micropogon), redfish (SciaEnops), flounder

(Paralichthyis), pinfish (Lagodon), and sea catfish (Galeichthys).

Tertiary consumers include flounder (Paralichthys), croaker (Micropogon),

trout (Cynoscion)2 redfish (Sciaenops)@ and drum (Pogonias The Laguna

Madre and Baffin Bay are of great ecological importance because they

constitute the most extensive hypersaline biotope in the United States.

In addition@ they are of considerable value to the commercial fishery

of the Texas coast.

RIVER MOUTH

This is a low salinity area (from 0.5 to 8 O/oo) found at the mouths

of rivers where freshwater is discharged into the upper bays. Bottom

sediments associated with this fluctuating regime are predominantly muds

and sandy muds. Depths range from about 3 to 7 feet. The water is

usually turbid. Heavy surges of river water and concurrent turbid

conditions during high rains followed by surges of salt water during

exceptional tides and low river discharge make the biotope unfavorable

for supporting a diverse community of organisms. Plant species include

the freshwater grasses Najas and Potamogeton and the brackish widgeon grass,

Ruppia martima. Common clams include Rangia cUneata near the lower

boundaries and the deep digging Mya clam in the area,near the upper

margins. Other clams include Palymosoda and Macoma. The snail Littoridina

is common in-some localities. Crustaceans include Callinectes and

Macrobrachium. The soft, muddy., organic-rich bottoms provide a habitat

for abundant ostracods. Foraminifers are not abundant in this biotope,

but a few including Candona,.Darwinula, and Physocypria are characteristic

indicators of the lower, more saline margin. Microscopic benthic diatoms

are usually abundant. The dominant phytoplankton'are dinoflagellates.

The characteristic'fresh to brackish water is usually high in humic

acids from upstream runoff. Turbidity) low salinity) and low pH values

from these humic acids preclude significant growth of oysters and other

sessile benthic shellfish. These tend to flourish in salinities from

10-30 O/oo. On the other hand) these conditions are favorable for young

shrimp and crabs which feed largely on the organic detritus flushed

down from the rivers and shelter in the widgeo.n grass Ruppia maritima.

CHANNEL

A channel is the bed of a natural stream of water or the deeper

part of a river, bay, harbor, strait', etc. Some channels are deve loped

by natural hydrologic processes while others are artificially constructed

by man. Both types are the major arteries through which aquatic organisms

move to spawn, feed and grow and may provide protection from rapid weather

induced changes of temperature and salinity. Channels@ like the open bay2

are relatively low in terms of primary productivity. They are, neverthe-

less, important links between biotopes.

Turbidity2 relatively high current flow, and sedimentation prevent

complex ecosystems in channels in certain cases, but in others, such as

in fresh and saltwater marshes) they may become a habitat for a

considerable number of species. '.Seasonal migrations of crustaceans and

fishes2 at times) create very heavy temporary concentrations of these

animals. The entrance of penaeid shrimp into a bay system such as

Corpus Christi Bay2 Texas corresponds to high'flow of the Nueces River

during spring and autumn. This coupling of peak migration and Increased

river flow is essential for the propagation of@penaeid shrimp. Pluxes

of important materials occur in bay systems via the channel systems

during seasonal high river flows. These include vitamins and other

dissolved organic compounds (Birke, 1968), nutrients (Nash,.1947),

lowered salinity (Odum and Wilson, 1962) and flushing and mixing activities

(Prichard, 1967). The indirect stimulus of incoming nutrients enhances

photosynthetic productivity (Nash, 1947, Odum and Wilson, 1962). Hoese

and Jones (1963) reported populations of fish and invertebrates in

Redfish Bay, Texas during spring and autumn, corresponding to period

of maximum productivity and food availability.

The composition of the flora and fauna in the channel biotope

fluctuates with habitat conditions. It would be difficult to categorize

the channel communities in static terms. However3, when the channels are

examined over a longer period (20 or 30 years)2 a fairly consistent@

seasonally related community can be identified.

Present year round are hogchockers (Trinectes), spot Leiostomus

xanthurus, flounder@ Paralichthys lethostigma2 pinfish Lagodon rhomboides)

blue crab, Callinectes sapidus@ various species of shrimp, in different

life-stages from larval to late juvenile, and mullet) Mugil cephalus.

Benthic organisms include molluscs@ particularly bivalves2 snails,

polychaetes, and several crab species.

BAY PLANKTONIC

It is difficult, if not impossible, to precisely delimit the

geographical boundaries of the bay planktonic biotqpe because of the

spatial and temporal variability exhibited by the plankton. Here the

environment is a moving mass of water which may exist at one time as

an independent@ more or less homogenous patch., while at other times,

it may mix indistinguishably intoalarger mass. Planktonic organisms.,

possessing only feeble powers of locomotion, are constrained to travel

within these water masses and are restricted from crossing any physical

or chemical boundaries. Frolander (1964) shows nine hypothetical

positions that might be assumed by.an estuarine zooplankton population

influenced by tidal phase and time of day while remaining in a given

salinity range. These positions are illustrated in the following diagram.

WATER SURFACF

.. ...... .. .
ESTUARY
WATER
aiiip'
y OCEAN
WATER

[email protected].

of given sollnity (ischo lines)
of time of mid-lide
-Nine hypothetical positions that might.be assumed by an estuarine
zooplankton population influenced by tidal phase and time of day while remaining
within a given salinity range.

Thebay planktonic biotope may vary from a s tate of greatpni-

formity in chemical and biotic composition to a state in which highly

distinctive patches form a mosaic of different size patches with observ-

able or poorly observable interfaces. An example of a well defined patch

.would be a phytoplankton "bloom" (11).

Phytoplankton are the primary producers within the system and

certain plankton associations are the most constant biological feature

of the biotope. Diatoms of the genera Rhizosolenia (1). Asterionella (2),

Coscinodiscus (3), Biddulphia (4), Thalassiora (17)., Thalassiothrix (18),

Thalassionema (19)) Gyrosigma (20), Nitzchia (21),.Skeletonema (22)., and

Actinoptychus (23) and dinoflagellates of the genera Ditylum (6), Ceratiu'm

(7)., and Peridinium (8),,(Figure 20) are microscopic phytoplankton

normally present in enormous numbers. Both groups utilize light energy

to fix carbon as "food reserves" or incorporate it as integral structural
components o@ the organisms themselves. The fixed carbon of these tiny-

plants is consumed by barely visible invertebrate zooplankton such as

copepods, CalanW-5--, sp. (24) and Candacea sp. (25)', (Figure 20). In this

way organic carbon is moved upward in the food chain as these small
copepods (animals) are consumed by even larger animals. Fish and shr@mp
larvae must have these lower organisms as food sources.

In general, diatoms dominate the winter flora., but share or yield

dominance to dinoflagellates during the summer. Nanoflagellates are

usually present throughout the year, but may exhibit spring or fall

blooms. Higher diversity levels tend to prevail in the lower margins

of the bay or estuary signifying greater variety in ecological niches.

Progressive diminution of diversity up bay indicates a reduced number

of niches resulting from gross pollution or other'unfavorable conditions

originating at the end of the bay.

In addition to phytoplankton and zooplankton, larval and post-

larval forms of numerous fish and crustacea@ many of commercial importance,

contribute to the total plankton biomass. Depending upon the life history

of the species involved@ these "meroplankton" may contribute a significant

proportion of the primary and secondary consumers in the bay planktonic,

biotope. It is a well known fact that vast numbers of larval and post-

larval shrimp (Penaeus) (14). mullet (Muqil)2 spot (Leiostomus) (15)@

croaker (Micropogon), trout (Cynoscion) (13), menhaden (Brevoortia))

f lounder (Paralichthys, and Quadrocellatus) (16) , and redf ish (Sciaenops

are found seasonally in,this biotope feeding on zooplankton such as

Paracalanus and "grazing" on the phytoplankton such.as the diatom

Thalassionema (19) and.dinoflagellates such as Skeletonema (22) and

Nitzschia, (21).

11
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BAY PLANKTONIC

1. Rhizosolenia styliformis - Diatom
2. AstL-riaiella -laT)onica - Diatom
3. Coscinodiscus 0radiatus Diatom
4. BiddulD8hLa mobiliensis Diatom
5. Chaetocer4as affinis Dinofl4agellate
6. Ditylum brightwellii Dinoflagellate
7. 0Oeratium tripos - Dinoflagellate
8. Peridinium oceanicum - Dinoflagellate
9. Ceratium fusus - Dinoflagellate
10. Peridiniumornatum - Dinoflagellate
11. Plankton b8lo--om
12. Aurelia aurelia 'jelly fish
13. CVnoscion arenarius Sand trout.
14. Penaeus aztecus - Brown shrimp
15. Leiostomus xanthurus - Spot
16. uadrocellatus anc6yclopsetta - Flounder
17. Thalassiora decipiens - Diatom
18. Thalassiothi-ix longissima - Diatom
19. Thalassionema nitzoides - Diatom
20. Gyr sigma sp. - Diatom
21. Nitzchia p0aradoxi4a - Diatom
22. Skeletonema costatum - Diatom
23. Actinopt0ychus undulatus - Diatom
24. Calanus sp. Copepod
2S. Candacea sp. Copepod
26. Sa6gitta macrocephla - Arrow worm
27. Aulac4antha scol6ymantha - Siliculose amoeba
28. For4aminifer4a
29. Larva of Orthopristes chrvsODterus Ho4gchoker.
30. Meg4alops stage of Carcinus maenus Crab
31. Larva of La0godon rhomboides -.Pinfish
32. Nauplius of Balanus - Barnacle
33. Zoea stage of Pa0gurus Hermit crab

PRAIRIE GRASSLANDS

The prairie grasslands biotope includes.the region defined by

Tharpe (1952) on the coastal prairie region. This region comprisps a@,,

strip thirty to fifty miles wide along the whole Texas coast southward

to northern Kennedy County., where it contacts the coastal dune region.

Tharpe (1952) divides it into an upper subregion (north of San Antonio

Bay to the Louisiana-Texas border) and a lower subregion (south of

San Antonio Bay to the Laguna Madre). The upper subregion has an

annual rainfall above 34 (up to 52) inches and the lower subregion

less than 34 inches (down to 26 inches, and sometimes lower)-. The

quantity of rainfall in the upper region is sufficient to produce tall

grass prairie, traversed by timber on stream flood plains or on low

sandy ridges and bordered by coastal marshes which occasionally extend

several miles inland. The Neches River2 for example, has marshes

almost bare of trees up to the vicinity of Beaumont. Southward these

marsh,es dwindle in size,, and the stature of grasses on the adjacent

prairie decreases and smaller grasses, prominent in the lower subregion,

begin to appear. Small oak woodland alternates with strips of prairie

(Costello 1969).

Seasonal changes-in plant., mammal and insect associations exemplify

the prairie grassland biotope as one of the most complex ecosystems.

The grasslands are typified by characteristic assemblages.' Wooded and

.shrubby borders, particularly along streams and around ponds usually

have specific populations of plants and.animals*(Costello, 1969).

In the vicinity of streams and ponds, red-shafted flickers, Lewist

woodpeckers, red-tailed hawks, crows@ grossbeaks, and blackcapped

chickadees are prevalent. Other frequent avian inhabitants of prairie

waters and adjacent vegetated borders are mallards, kingfishers, great

blue herons@ marsh wrens and several species of blackbirds. The long-

billed curlew (Numenius americanus), killdeer (Charadruis vociferus) and

nighthawk (Chordeiles minor), meadowlark (Sturnella neglecta), several

species of owls, including burrowing owls (Speotyto cunicularia hypugaea)

and barn owls (Tvto alba Pratincola), and eagles of the generus Bubo are

representative birds of the open prairies.

Insects are extensive in this biotope. They include grasshoppers,

katydids, crickets, beetles@ butterflies., and bumblebees. Common

grasshoppers are two-striped grasshopper (Melanopl us bivitatus), clear-

winged grasshopper (M. femurrubrium , the lubber grasshopper (Brachystola

magna), and the spotted bird grasshopper' (Schistocerca lineata).

The katydids and crickets., are usually abundant including the

common meadow katydid (Orchelium vulgare) the round winged katydid

(Amblycorypha rotundifolia parvipennis), true crickets of the family

Gryllidae and the tree crickets (Oecanthinae var.). Other representative

insects include the common beetle (Canthon laevig), butterflies including

the red admiral (Vanessa atalanta), the painted lady (Y. cardui),.the

goatweed butterfly (Anaea andria)2 the sulphur butterfly (Phoebis sennae)

and the giant swallowtail butterfly (Papilio cresphontes). Skippers,

the dull-colored butterflies with recurved hooks beyond the club of the

antennae@ such as the checkered skipper (Pvrqus communis) feed on plants

of the mallow family.

Several dozen kinds of bumblebees live in this biotope and are

valuable as plant pollenators. One common variety is B-2mbu-s ternarius.

Reptiles found in the prairie biotope includes the prairie rattle-

snake (Crotalus virdis viridis ullsnake (Pituophis melanoleucus 2A@Li),

western diamondback rattlesnake atrox) and the blind snake (Leptotvphlops

dulcis dulcis). Other reptiles include the collared lizard (Crotaphytus

collaris collaris), and the snapping turtle (Chelydra serpentium serpentium).

Amphibians with important roles are the spadefoot toad (Scaphiopus

bombifrons)@ bullfrog (Rana catesbeiana) and leopard frog pipiens).

A number of grasses, trees and herbs are associated with the

prairie habitat. Predominant trees include mesquite (Prosopis glandulosa)

and a variety of oaks (Quercus spp.). Grasses, the dominant plants,

include little bluestem (Andropogon scoparius), big bluestem (L. gerarai),

Indiangrass (Sorghastrum spp.), Gulf muhly grass (Muhlenbergia capillaris

var. Filipes), eastern gamagrass (Tripsacum dactyloides), broomsedge

bluestem (A. virginicus), smutgrass (Sporobolus poiretii) and tumblegrass

(Schendonardus paniculatus). Herbs include western ragweed (Ambrosia

psilostachya)) and yankeeweed (Eupatorium compositifolium Cacti include

the prickly pear (Opuntia

UPLAND DECIDUOUS FOREST

Because plants play a heavy role as primary producers, slight

changes in vegetation can exert strong influences on inhabitants of an

area through the multiple food chains existing in the assemblage. Also,,,,

any significant change in vegetation reflects alterations in'cover

available to animals and tends to limit faunal distribution. Two

representative biotopes) the upland deciduous forest and the river

floodplain forest are found in the coastal zone. The former is described

below, while the latter is described in this report under a separate

heading because the composition and appearance of the two differ vastly,

both qualitatively and quantitatively.

The upland forest is the normal climax for well drained areas such

as Brazos County@ wherever moisture conditions will support tree growth

(Abbott, 1966). Drier upland areas are covered by coastal prairie when

undisturbed.

In the upland forest', the canopy is low, usually less than 50 ft.

in height, and is composed of small-leafed@ deciduous trees, mostly

post oaks (Quercus stellatitWangh). Layering is.indistinct, and the lower

strata, mixtures of medium-to-small leafed deciduous and evergreen plants-,

.may penetrate the canopy. Yaupon (Ilex vomitoria Ait.) is consistent as

a shrub. Trees include blackjack oak (guercus marilandica Muenchh.).
post oak (Quercus stellata Wangh.),,winged elm (Ulmus alata Michx.).,and

water oak (Quercus nigra L.). Shrubs include the eastern red cedar

(Juniperus virginiana L.), blueberry (Vaccinium sp.), American beauty-berry

(Callicarpa americana L.), St. Andrew's cross (Ascyrum hypericoides L.),

wollybucket bumelia (Bumelia lanuginosa (Michx.) Pers.), and Texas

Hercules-club pricly ash (Zanthoxylum clara-herculis L.).

Along the lower margin of the upland forest, where this biotope

interfaces with the river floodplain biotope, the loblolly pine (Pinus

taeda) predominates.

Representative animals include the Texas whitetail deer (Odocoileus

virginianus texanus), bobcat (Lxnx rufus), bluejay (Cyanocitta christata),

quail@ turkey., squirrels, and grey fox. The coachwhip (Masticophis

testaceus) and the western diamondback rattler (Crotalus atrox) are

typical reptiles.

The pronounced differences in numbers of species in each category

suggest that the upland forest biotope is, relatively, a much less

disturbed and more specialized habitat than the river floodplain (Abbott,

1966).

RIVER FLOODPLAIN FOREST

Many biotopes depend extensively on solar energy, fixed as plant

material,, that is imported from upstream sources. One of these sources

is the river floodplain forest. This biotope provides a rich variety

of habitats.. Much of the plant material.which falls or is blown into

the rivers is finally introduced into the biotopes downstream. This

material is composed of about si5(ty percent leaves, twenty percent

branches and twenty percent representing a miscellany of bark, scale,

flowers and fruit.

The vertical stratification of the fioodplain forest is readily

apparent. The upper canopy is approximately one hundred feet high and

contains a mixture of broad-leafed deciduous. The middle story, between

fifteen and fifty feet is composed of smaller individuals of the same

.types. Finally, the ground story consists of low tangled thickets

dominated by shrubs. There are few unshaded patches. The soil is damp

and has the firm2 slightly sticky consistency of an alluvial clay loam.

Occasional flooding produces numerous small hillocks and gullies.

These periodic inundations disrupt the floral and faunal communities

and this is reflected by the large number of species-competing for life

in this biotope. Abbott (1966) cited thirty-four species of woody plants

from the river floodplain as opposed to fourteen from the upper

deciduous forest. Trees normally found in this biotope include the

following, listed in tabular form by scientific and common names.

Trees

Ulmus crassifolia. Nutt. - Cedar elm

Ulmus americana L. - American elm

Celtis occidentalis L. - Common hackberry

Celtis laevigata Wild. - Sugar hackberry

Morus rubra L. - Red mulberry

Diospyros virginia L. - Common persimmon (Fig. 21, No. 9)

Fraxinus pennsylvania landeolata Sarg. - Green ash

Carya illinoensis (Wang.) Koch - Pecan

Carya cordiformis (Wang.) Koch - Bitternut hickory

Quercus falcata Michx. - Southern red oak

Quercus lyrata Walt. - Overcup oak

Planera aquatica (Walt.) Gmel. - Water elm

Other trees found in this area are the following, by scientific

and common name. Numbers indicate position on Fig. 21.

Quercus stellata - Post oak (1)

Quercus nigra Water oak (2,18)

Ulumus alata Winged elm (3)

Salix nigra Black willow (11)

Salix caroliniana - Coastal plain willow (12,20)

The predominant shrubs are shown here by scientific name and

common name.

Rubus sp. - Dewberry

Crataegus sp. - Hawthorne

Ampelopsis arborea (L.) Rusby Pepper Vine

Vitis cinerea Engelm. Sweet winter grape

Ilex decidua Walt. - Possum-haw holly

Symphoricarpos sp. - Snowberry

Bigonia radicans L. - Common trumpet-creeper

Rhus sp. - Sumac

Zanthoxylum clava-herculis L. TeXas hercules-club, prickly-ash

Also found are briars Smilax sp. (5) and yaupon, Ilex vomitoria (10,19).

Plants found growing in the water include cattails Typh a domingensis (13)

and water hyacinth Eichhornia crassipes (14),

Only qualitative comparisons of the upland deciduous forest and.

the river floodplain forest biotope fauna can be made (Abbott, 1966).

The upland forest, with low trees and heavy underbrush is capable'of

providing ample cover for terrestrial forms, while the dry., well drained

soil can sustain burrowing forms. The floodplain forest is inhospitable

to these groups during seasons in which occasional flooding of the ground

level occurs. There are, however, many arboreal niches for'squirrels

Sciurus carolinensis (7), turkeys Meleagris gallopavo (6), as well as

cover for such insects as the grasshopper Schistocerca americana, (15),

nine-spotted lady bug Coccinella novemnotata (17), bluebottle fly

Calliphora sp. (22) and mosquitos of genus Cul ex (23). Occasional grazers

are quail Colinus virgini nus (8) and Texas white tailed deer Odocoileus

virginianus (4). Shown from the water are the water scavenger Eydrophilus

triangularis (16)) crayfish Procambarus clarki (21) and a tadpole Rana sp.

(24).

A minute breakdown would undoubtedly reveal many more niches in

the floodplain forest due to its greater complexity. Intensiv6 competition

among plants results in a high rate of net production in the river flood-
plain biotope, allowing large numbers of primary consumers with their

associated predator chains.

At the lower border and at waterways, the river floodplain merges

into the freshwater marsh biotope with its abundant growths of marsh hay

cordgrass, Spartina. patens, and black rush, Juncus roemerianus.

3
2

1 13

4 6
0
15V 5 9 14

6
7
z
'@@j
4
__L_

ze
10

V9, .%

I ___j

Mli-

j@P
4VI
1W

Figure 21. River Floodplain Forest

RIVER FLOODPLAIN FOREST

1. Quercus stellata - Post oak
2. Quercus nigra - Water oak
3. Ulmus alata - Winged elm
4. Odocoiqleus virginianus - Texas white tailed deer
5. Smilax sp. - Briar
6. Meleagris gallopavo - Wild turkey
7. Sciurus carolinensis - Gray squirrel
8. Colinus virginianus - Quail
9. Diospyros virginiana - Persimmon
10. Ilex vomitoria - Yaupon
11. Salix nigra - Black willow
12. Salix caroliniana - Coastal plain willow
13. Typha domingensis - Cattails
14. Eichhornia crassipes - Water hyacinth
15. Schistocerca americana - Grasshopper
16. Hydrophilus triangularis - Water scavenger
17. Coccinella novemnotata - Spotted lady bug
18. Quercus nigrqa - Water oak
19. Ilex vomitoria- Yaupon
20. Salix caroliniana - Coastal plain willow
21. Procambarus clarki - Crayfish
22. Calliphora sp. - Blue bottle fly
23. Culex sp. - Common mosquito
24. Rana sp. Tadpole

DISCUSSION

Gulf estuaries and coastal lagoons are among the most important

productive areas of the world. The submerged and shoreline vegetation

provides a substantial part of this productivity (Westlake, 1963) and

with plankton and land runoff of organic matter and nutrients account

for large fish and shellfish population. The areas have important

recreational uses and are necessary nursery areas for many sport and

commercial fisheries. Unfortunately, these delicate systems are presently

threatened by man's activities. Some of these activities are summarized

on Tdbl@? 2 Such.activities are components of a variety of

economically important sectors such as agricultural(use of fertilizers

and biocides). petrochemical industry (gaseous and liquid waste disposal),

mining (well development), construction (excavation, drainage, filling)

and navigation (canals, channels). Competition for coastal zone

resources, including rivers, bays, estuaries and lagoons will become

more intense as development continues. It is imperative that sensible

form of land and water use be devised. Returning to Table 2 we have

attempted to relate 17 activities in the coastal zone to the 18 biotopes

described. Some of these have, at the present state of the art@ severe

environmental implications. Others do not. For example, traversing

dunes with vehicles will cause severe upset to that biotope. Inland

construction, on the other hand, will have little impact on the coastal

.Gulf biotope. A more subtle impact would be the discharge of waste

gases via water into a channel biotope. As an hypothetical case, one

activity might involve construction of dwellings or industrial buildings

on unstabilized dunes.

Tab'I e 2
THE IMPACT OF MAN'S ACTIVITIE-S ON THE COASTAL BIOTOPES

4.3 4.3
(a @j

4-4 4J 0j
BIOTOPES
QI j
M -W 1-1 a Gj

ej
q
rj
AJ fu
q) (U
-1
FX4 @-i a4 f!
q -Ii
co v 4J tn ru -i
COASTAL ZONE 114
0
T I ES ZrI
ACTIVI

1. Liquid Waste Disposal 4 3. 3 4 5 5 5 5 4 4 4. 5 5 5 5 0 1 3
2. Gaseous rVaS4-e Dis- sal 1 0 0 3 1 3 0 5 0 0 0 4 5 4 4 0 0 0
3. Solid Waste Disposal 0 4 3 0 4 2 5 5 2 2 1 4 5 2 0 4 5 5
4. Olffshore Construction 2 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0
5. Coastal Construction 2 5 0 0 1 1 4 4 3 3 2 1 0 2 0 0 0 2
6. Iniand Construct-ion 0 0 0 0 0 0 0 0 0 0 0 0 0 1 0 5 4 4
7. Land Canals 1 0 0 0 4 0 4 0 3 3 0 0 0 0 0 4 0 5
S. O.Efshore Channels 1 0 0 3 5 5 4 4 3 4 2 2 3 4 4 0 0 0
9. Dredging & 13,,.-)oi.Z Disposal 4 0 5 5 5 5 5 5 5 4 3 5 4 5 1 0 0 1
-70. Eyca va t ,on 0 5 0 0 5 3 4 3 5 2 2 1 1 0 0 2 1 2
11. Drainage 0 0 0 0 0 0 4 5 2 1 2 2 3 0 0 3 0 1
0 0 0 0 4 4 5 5 3 3 3 4 3 0 0 1 1 1
.113. Draining 0 0 0 0 4 0 5 5 4 1 2 2 3 0 0 0 0 0
14. Well Development 2 3 4 1 4 1 1 1 1 1 1 3 1 1 1 3 1 1
15. Devegetation 0 5 4 0 0 2 . 5 5 1 1 1 0 0 0 0 5 5 5
16. Traversing with Vehicles 0 5 4, 0 .0 0 1 2 0 0 0 0 0 0 0 4 1 0
17. Use of Fer4-ijiZerS Biocides 0 5 4 2 5 5 5 5 0 1 3 4 4 5 5 4 4 4

Two questions arise: (1) can the decision makers assure structural

integrity and pleasing esthetic quality simultaneously? (2) how much

can the biotope be altered without significant loss of productivity?

To answer these questions, the decision maker could elect to employ

extensive rather than intensive construction. By limiting the number

of buildings per unit of siting, stabilizing the dunes with sound

construction practices and cultivating the remaining flora construction

that combines form and function as well as maintaining the environment

may be achieved.

Some biotopes, the jetty and bulkhead, can be used intensively.

Others, like the oyster reef cannot tolerate intensive pressure from

man. Radical changes may sometimes be followed by fairly rapid recovery.

For example, grassflats can return to normal, and sometimes enhanced,

productivity after nearby dredging operations, if proper engineering

practices are adhered to during operations. Conversely, pollutants

incorporated in the sediments of the bay planktonic biotope might

require decades or even centuries to return to normal background levels.

One environmental dysfunction -rarely appears in a single biotope because

of interdependence of the biotopes. A flood borne slug of fresh water

into the river estuar@ (a natural dysfunction) or excessive impoundment

during seasons of low rainfall (a.manmade.dysfunction) will both be

felt by the sensitive biotopes.downstream.

Green (1968) reported on important species and their roles in

estuarine systems. Life cycles, distributions, seasonal regimes, food

habits, predators) and responses to various factors need to be more

completely understood. The organismic approach is an honored,tradition.

But, the management of the ecosystems requires an understanding of the

behavior of combinations of organisms. It is on the direct experimental

study of the coastal ecosystem that this paper hopes to focus attention.

Biological and economic aDDrOaches need to be united. Odum et a!.

(1969) found in their survey that documents from the two backgrounds,

appeared to have no relationship, while dealing with the same estuarine

resources. The practical engineering associated with waste loading

factors cannot be adequately implemented until the coastal ecosystem

is more quantitatively understood.

From Table 2 it can be inferred that some biotopes are in critical

danger in terms of current levels of man's activity. It is suggested

that three biotopes, the salt marsh, grassflat, and dune are the most

prone to ineversible damage. This in no way implies that the other

biotopes are not endangered. On the contrary, one must proceed with

great caution. It is only reasonable to call for close cooperation

and forthright action from private and public sectors to assure productive

use of these resources. As man draws from the coastal resources,

alteration will be inevitable. In accepting this view, one should seek

ways to optimize the alterations rather than minimizing their impact.

For example, dredging and the associated spoiling alter the adjacent

biotopes. Yet spoil islands can be enhanced with small losses in

produc'@--ivity, by planting, and made esthetically pleasing with landscaping.

There are certain disturbances to coastal biotopes that are harmful

as currently practiced. These are listed below. It is hoped that

science and management can devise alternatives for better

the coastal environment.

.7
(1) Impoundments. The construction of dams on coastal streams has

limited the distance that migrating forms may traverse upstream for

spawning and nursing (Andrew and Green, 1960; Copeland, 1966; French

and Wohle, 1966; Saila, 1962; Smith, 1966; Talbot,.1966; and Walburg

and Nichols, 1967).

(2) Dredging. The dredging of canals has upset the current and

circulation patterns in many coastal systems, which alters the transport

route for larvae of mary river and sea-spawned organisms relying on

current patterns to arrive in coastal systems (Smith, 1966).

(3) Filling. The practice of bulkheading and filling shallow

coastal areas to create real estate has removed significant acres of

valuable nursery area utilized by migrating organisms (Smith, 1966),

and (Talbot, 1966).

(4) Wastes (Solid, liquid, gaseous). Various kinds of pollutants

which enter coastal systems have been shown to be either toxic to

migrating organisms or in some way alter their metabolism so that they

no longer will tolerate the affected area (Odum et al., 1969).

(5) Organic Loading. Large concentrations of organic materials

from upstream sources usually exert a high oxygen demand on the system,

thus compe-Cing with the organisms for available oxygen and restraining

the migration of organisms (Bishai, 1962), (Herman et al., 1966), and

(Waldichuk, 1966).

(6) Pesticides. Pesticides may differentially affect different

life-cycle stu.-'-os of migrating organisms, thus either preventing spawning

or 'L--i:,vae that come in contact with it. Very small concentrations

of insecticides are reported to cause shrimp in the Texas coastal systems

to cease inhabiting these waters (Chin and Allen, 1957). Blue crabs are

aerial imagery to identify floral assemblages has been reported by

Kolipinski and Higer (1970). Contact, e.q. in situ sensing needs to be

coordinated with remote sensing. This way the large time expenditures

for field survey could be greatly reduced and lead times required -for

the older survey techniques could be shortened.

(2) Toxicity. Systemic mc-_-Cabolic stress on various indicator

organisms e.cr. microorganisms, invertebrates and vertebrates determined

by toxicity bioassay could provide valuable data establishing threshold

limits for these organisms. Long term quantiative loading limits for

different coastal ecosystems might then become more reliable.

(3) Ecography. Detailed ecosystem maps for coastal states need

to be developed. From there, time and spatial distributions for entire

biotopes might be determined.

(4) Resource Management. There is a growing need for study and

resource management by system rather than species.

(5) Economics. A formula should be devised by which services that

stimulate coastal zone biotic processes, such as encouraging desirable

fish food chains can be recognized. Similarly, programs sh3@.__Lf be

6aveloped to encourage public and private agencies to plan on enhancing

areas in which they make changes rather than simply changing and abandoning

the areas. It is a taken-for-granted principle in the economy of man

that payment is ,,@cade for goods and services. If such enhancements can

be made part of the price for development in the coastal zone;, the flow

of this kind of currency will allow' each participant to compete for survival.

Such ?rocgrams will- insure that the coastal zone becomes part of the

economy of man and nature rather than part of an operation in the

zone is reduced in its usefulness in terms of future development.

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