Habitat Loss

Aug 17 • Ocean Matters • 174 Views • Comments Off on Habitat Loss

habitat-lossThe primary threat to the world’s biodiversity is habitat destruction, sometimes referred to habitat loss. Habitat loss alters or eliminates the conditions needed for plants and animals to survive. Deforestation is of particular concern. Canada’s old growth forests, for example, are now under threat from logging activities. Tropical forests are among the most biologically rich areas on Earth. The UN Food and Agriculture Organization (FAO) recently estimated the annual rate of loss of these ecosystems was nearly 2% by the end of the 1990s. This means that an area the size of Florida is clearcut each year in forested tropical regions alone. Unfortunately, similar levels of habitat destruction are occurring in ecosystems around the world.

Aside from large-scale commercial deforestation, other factors lead to loss of habitat: forests converted to agriculture and livestock production; coastal development; and estuaries, bogs and swamps converted to landfills, dumps and residential areas. These biologically diverse forests support a wide variety of animal, bird and plant life that can’t be found elsewhere.

Another contributing factor is urbanization, which means that natural ecosystems and agricultural lands are lost as they are converted into shopping centers, housing developments and office space. Urban development brings related problems, such as vehicle and factory pollution in the form of greenhouse gases and other emissions, and the generation of toxic waste, garbage and sewage.
Habitat loss is an important factor coral reefs. Corals are small animals which belong to the group cnidaria. Other cnidarians include hydras, jellyfish, and sea anemones. Corals are sessile animals, meaning they are not mobile but stay fixed in one place. They feed by reaching out with tentacles to catch prey such as small fish and planktonic animals. Corals live in colonies consisting of many individuals, each of which is called polyp. They secrete a hard calcium carbonate skeleton, which serves as a uniform base for the colony. The skeleton also provides protection, as the polyps can contract into the structure if predators approach. It is these hard skeletal structures that build up coral reefs over time. Different species of coral build structures of various sizes and shapes (“brain corals,” “fan corals,” etc.), creating amazing diversity and complexity in the coral reef ecosystem.

Most reef-dwelling corals have a symbiotic (mutually beneficial) relationship with algae called zooxanthellae. The plant-like algae live inside the coral polyps and perform photosynthesis, producing food which is shared with the coral. In exchange the coral provides the algae with protection and access to light, which is necessary for photosynthesis. The zooxanthellae also lend their color to their coral symbionts. Coral bleaching occurs when corals lose their zooxanthellae, exposing the white calcium carbonate skeletons of the coral colony. Habitat loss or change in habitat for corals can result from excess shade, increased levels of ultraviolet radiation, sedimentation, pollution, salinity changes, and increased temperatures. Many of these are a result of human activities. Conservation Science Institute Science Director, Tom Okey, and fellow, Carlos G. A. Ormond, are studying coral.


Appledoorn, R.S., M. Nemeth, J. Vasslides, and M. Scharer. 2000. The effect of fish traps on benthic habitats off La Parguero, Puerto Rico. Report to the Caribbean Fishery Management Council, Hato Rey, Puerto Rico.

Ardrizzone, G.D., P. Tucci, A. Somaschini, and A. Bellauscio. 2000. Is bottom trawling partly responsible for the regression of Posidonia oceanica meadows in the Mediterranean Sea? Pp. 37-46 in M.J. Kaiser and S.J. de Groot. The Effects of Fishing on Non-target Species and Habitats. Blackwell Science.

Auster, P.J. 1998. A conceptual model of the impacts of fishing gear on the integrity of fish habitats. Conservation Biology 12(6): 1198-1203.

Auster, P.J. and R.W. Langton. 1999. The effects of fishing on fish habitat. Pp. 150-187 in L. Benaka, ed. Fish habitat: essential fish habitat and rehabilitation. American Fisheries Society, Symposium 22, Bethesda, Maryland.

Auster, P.J., R.J. Malatesta, R.W. Langton, L. Watling, P.C. Valentine, C.L.S. Donaldson, E.W. Langton, A.N. Shepard, and I.G. Babb. 1996. The impacts of mobile fishing gear on seafloor habitats in the Gulf of Maine (northwest Atlantic): implications for conservation of fish populations. Reviews in Fisheries Science 4(2):185-202.

Auster, P.J., L. Watling, and A. Reiser. 1997. Comment: The interface between fisheries research and habitat management. North American Journal of Fisheries Management 17:591-595.

Ball, B., B. Munday, and I. Tuck. 2000. Effects of otter trawling on the benthos and environment in muddy sediments. Pp. 69-82 in M.J. Kaiser and S.J. de Groot. The Effects of Fishing on Non-target Species and Habitats. Blackwell Science.

Bergman, M.J.N., and M. Hup. 1992. Direct effects of beam trawling on macrofauna in a sandy sediment in the southern North Sea. ICES Journal of Marine Science 49:5-11.

Black, K.P. and G.D. Parry. 1999. Entrainment, dispersal, and settlement of scallop dredge sediment plumes: field measurements and numerical modelling. Canadian Journal of Fisheries and Aquatic Science 56:2271-2281.

Bradshaw, C., L.O. Veale, A.S. Hill, and A.R. Brand. 2000. The effects of scallop dredging on gravelly seabed communities. Pp. 83-104 in M.J. Kaiser and S.J. de Groot. The Effects of Fishing on Non-target Species and Habitats. Blackwell Science.

Bradstock, M. and D.P. Grodon. 1983. Coral-like bryozoan growths in Tasman Bay, and their protection to conserve commercial fish stocks. New Zealand Journal of Marine and Freshwater Research 17:159-163.

Brambati, A. and G. Fontolan. 1990. Sediment resuspension induced by clam fishing with hydraulic dredges in the Gulf of Venice (Adriatic Sea). A preliminary experimental approach. Bollettino Di Oceanologia Teorica Ed Applicata 8(2):113-121.

Brown, B., W.H. Wilson, Jr. 1997. The role of commercial digging of mudflats as an agent for change of infaunal intertidal populations. Journal of Experimental Marine Biology and Ecology 218:49-61.

Cappo, M., D.M. Alongi, D. Williams, and N. Duke. 1998. A review and synthesis of Australian fisheries habitat research. Volume 2: Scoping Review, Issue 4: Effects of Harvesting on Biodiversity and Ecosystems. FRDC 95/055.

Currie, D.R. and G.D. Parry. 1999. Impacts and efficiency of scallop dredging on different soft substrates. Canadian Journal of Fisheries and Aquatic Science 56:539-550.

Engel, J. and R. Kvitek 1998. Effects of otter trawling on a benthic community in Monterey Bay National Marine Sanctuary. Conservation Biology 12(6):1204-1214.

Eno, N.C., D.S. MacDonald, J.A.M. Kinnear, S.C. Amos, C.J. Chapman, R.A. Clark, F.P.D. Bunker, and C. Munro. 2001. Effects of crustacean traps on benthic fauna. ICES Journal of Marine Science 58:11-20.

Fonseca, M.S., G.W. Thayer, A.J. Chester and C. Foltz. 1984. Impact of scallop harvesting on eelgrass (Zostera marina) meadows: implications for management. North American Journal of Fisheries Management 4:286-293.

Freese, L., P.J. Auster, J. Heifetz, and B.L. Wing. 1999. Effects of trawling on seafloor habitat and associated invertebrate taxa in the Gulf of Alaska. Marine Ecology Progress Series 182:119-126.

Frid, C.L.J. and R.A. Clark 2000. Long-term changes in North Sea benthos: discerning the role of fisheries. Pp. 198-216 in M.J. Kaiser and S.J. de Groot. The Effects of Fishing on Non-target Species and Habitat. Blackwell Science.

Gotceitas, V, S. Fraser and J. A. Brown. 1995. Habitat use by juvenile Atlantic cod (Gadus morhua) in the presence of an actively foraging and non-foraging predator. Mar Biol 123:421-430.

Gotceitas, V., S. Fraser and J. A. Brown. 1997. Use of eelgrass beds (Zostera marina) by juvenile Atlantic cod (Gadus morhua). Can J Fish Aquat Sci 54:1306-1319.

Hall, S.J. 1999. The Effects of Fishing on Marine Ecosystems and Communities. Blackwell Science. Oxford, United Kingdom. 274 p.

Hughes, J.E., Deegan, L.A., Wyda, J.C., Weaver, M.J., and Wright, A. 2002. The effects of eelgrass habitat loss on estuarine fish communities of southern new England. Estuaries 25(2): 235-249.

Kaiser, M.J. 1996. Starfish damage as an indicator of trawling intensity. Marine Ecology Progress Series 134:303-307.

Kroencke, I. 1995. Long-term changes in North Sea benthos. Senckenbergiana Maritima 26(1-2):73-80.

Langton, R.W., P.J. Auster, and D.C. Schneider. 1994. A spatial and temporal perspective on fish distributions: improving our definition of fisheries habitat in the Gulf of Maine; pp. 25-50 in Stevenson, D. and E. Braasch, eds. Gulf of Maine Habitat Workshop Proceedings. RARGOM Report no. 94-2.

Lenihan, H.S. and C.H. Peterson. 1998. How habitat degradation through fishery disturbance enhances impacts of hypoxia on oyster reefs. Ecological Applications 8(1):128-140.

Mountain, D.G., R.W. Langton, and L. Watling. 1994. Oceanic processes and benthic substrates: influences on demersal fish habitats and benthic communities; pp. 20-25 in Langton, R.W., J.B. Pearce, and J.A. Gibson, eds. Selected Living Resources, Habitat Conditions, and Human Perturbations of the Gulf of Maine: Environmental and Ecological Considerations for Fishery Management. NOAA Tech. Memo. NMFS-NE-106. Woods Hole, MA. 70 p.

Ohman, M.C., A. Rajasuriya, and O. Linden. 1993. Human disturbance on coral reefs in Sri Lanka: a case study. Ambio 22:474-480.

Reise, K. and A. Schubert. 1987. Macrobenthic turnover in the subtidal Wadden Sea: the Norderaue revisited after 60 years. Helgolander Meeresunters 41:69-82.

Rijnsdorp, A.D. and P.I. Van Leeuwen. 1996. Changes in growth of North Sea plaice since 1950 in relation to density, eutrophication, beam trawl effort, and temperature. ICES Journal of Marine Science 53:1199-1213.

Rothschild, B.J., J.S. Ault, P. Goulletquer, and M. Heral. 1994. Decline of the Chesapeake Bay oyster population: a century of habitat destruction and overfishing. Marine Ecology Progress Series 111:29-39.

Stephan, C.D., R.L. Peuser, and M.S. Fonseca. 2000. Evaluating fishing gear impacts to submerged aquatic vegetation and determining mitigation strategies. ASMFC Habitat Management Series #5. 38 p.

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