Biodiversity and Conservation Dr. Ashraful Azam Khan January 2019 Department of Fisheries Biodiversity What is Biodiversity? ◼ Biodiversity is the variety of life in an area that is determined by the numbe r of different species in that area. ◼ Biodiversity increases the stability of an ecosystem and contributes to the health of the biosphere. ◼ Main idea: Biodiversity maintains a h ealthy biosphere and provides direct and indirect value to humans. Biodiversity Aquatic Biodiversity ◼ We know fairly little about the biodiv ersity of the world’s marine and fresh water systems. ◼ The greatest marine biodiversity occ urs in coral reefs, estuaries and the de ep ocean floor. ◼ Biodiversity is higher near the coast a nd surface because of habitat and foo d source variety. Biodiversity Resource Biodiversity Resource: ◼ Something that contains valuable ma terials. Example: Forests, Bodies of water Renewable Resource: ◼ A resource that is replenished for futu re use. Example: Reforestation Biodiversity Resource Biodiversity Sustainable Yield: ◼ The amount of the resource that can be harvested without reducing the fut ure supply. Fishery: ◼ An area with a large population of val uable aquatic organisms. Sustainable? Limits: Amount and size allowed Me thods: Type of gear allowed Aquaculture: Fish farms Biodiversity Why is this important ? There are direct and indirect economic, aesthetic, and scientific reasons for preserving biodiversity. Economic Value: ◼ ◼ Resources and ecotourism Ecosystem Value: ◼ All species are connected Biodiversity Direct Economic Value ◼ Humans depend on plants and animals to provide food, clothing, energy, medicine, and shelter. ◼ Genetic diversity in species that might be needed in the future is important because … ◼ Most of the world’s food crops come fro m just a few species. ◼ Many of the medicines that are used t oday are derived from plants or other organisms. ◼ Scientists continue to find new extract s from plants and other organisms tha t help in the treatment of human disea ses. Biodiversity Indirect Economic Value ◼ A healthy biosphere provides many servic es to humans and other organisms that liv e on Earth. ◼ Green plants provide oxygen to the atmos phere and remove carbon dioxide. ◼ Healthy ecosystems provide protection a gainst floods and droughts, generate and preserve healthful fertile soils, detoxify an d decompose wastes, and regulate local cl imates. Biodiversity Aesthetic and Scientific Valu e ◼ It is difficult to attach a value to somethin g that is beautiful or something that is int eresting to study. ◼ The value of biodiversity and healthy ecos ystems would be more obvious to us. Biodiversity Extinction ◼ Disappearance of all members of a specie s – this is increasing! Example: Golden toad Biodiversity Extinction Rate ◼ The gradual process of species becoming extinct is known as bac kground extinction. ◼ Mass extinction is an event in which a large percentage of all livi ng species become extinct in a relatively short period of time. ◼ Five Most Recent Mass Extinctions 1. Cretaceous Period - about 65 million years ago – Ammonite 2. Triassic Period – about 200 million years ago – Cynognathus 3. Permain Period – about 251 million years ago – Trilobite 4. Devonian Period – about 360 million years ago – Dinichthys 5. Ordovician Period – about 444 million years ago – Graptolites Biodiversity Extinction Rate Biodiversity Extinction Rate ◼ The accelerated loss of species began several centuries ago. ◼ Many of the species’ extinction in the past have occurred on islan ds. ◼ Islands are particularly vulnerable to extinction due to several fac tors. ◼ Many species evolved without the presence of natural predato rs. ◼ Introduction of nonnative species with diseases. ◼ Islands have relatively small populations sizes Biodiversity Threats to Biodiversity ◼ Human activities have destroyed, disrupted or degraded a large p roportion of the world’s coastal, marine and freshwater ecosyste ms. ◼ ◼ ◼ ◼ Approximately 20% of the world's coral reefs have been destr oyed. During the past 100 years, sea levels have risen 10-25 centimet ers. We have destroyed more than 1/3 of the world’s mangrove for ests for shipping lanes. Area of ocean before and after a trawler net, acting like a giant pl ow, scraped it. Biodiversity Threats to Biodiversity ◼ Harmful invasive species are an increasing threat to marine and f reshwater biodiversity. ◼ ◼ Bio invaders are blamed for about 2/3 of fish extinctions in b etween 1900-2000. Almost half of the world’s people live on or near a coastal zone an d 80% of ocean water pollution comes from land-based human ac tivities. Biodiversity Causes of Biodiversity los s ◼ ◼ ◼ ◼ Habitat loss Overexploitation and Extinction Pollution Invasive species Biodiversity Habitat loss ◼ If a habitat is destroyed or disrup ted, the native species might hav e to relocate or they will die. ◼ Destruction of habitat - such as t he clearing of tropical rainforests , has a direct impact on global bi odiversity. ◼ Disruption of habitat - the declin ing population of one species ca n affect an entire ecosystem. Biodiversity Overexploitation ◼ Overexploitation, or excessive use, of species that have economic value is a factor increasing the current rate of e xtinction. ◼ Historically, overexploitation was the primary cause of species extinction. ◼ Bison ◼ Passenger Pigeons ◼ Ocelot ◼ Rhinoceros Biodiversity Overfishing ◼ About 75% of the world’s commercially va luable marine fish species are over fished or fished near their sustainable limits. ◼ ◼ ◼ ◼ Big fish are becoming scarce. Smaller fish are next. We throw away 30% of the fish we cat ch. We needlessly kill sea mammals and birds. Biodiversity Overfishing Fish farming in cage Spotter airplane Trawler fishing Purse-seine fishing Sonar Trawl bag Long line fishin g Lines with hooks Deep sea aquacul ture cage Fish schoo l Drift-net fishing Fish caught by gills Biodiversity Pollution ◼ Each year plastic items dumped from ships and left as litter on beaches thre aten marine life. Biodiversity Pollution – Biological Magnification ◼ Pollution and atmospheric changes threat en biodiversity and global stability. ◼ Biological magnification is the increasing concentration of toxic substances in orga nisms as trophic levels increase in a food chain or food web. ◼ Pesticides - DDT Biodiversity Pollution – Acid Rain ◼ Sulfur and nitrogen compounds react with water and other subst ances in the air to form sulfuric acid and nitric acid. ◼ Acid precipitation removes calcium, potassium, and other nutrie nts from the soil, depriving plants of these nutrients. ◼ It damages plant tissue and slows their growth. ◼ Sometimes, the acid concentration is so high in lakes, rivers, and streams that fish and other organisms die. Biodiversity Pollution – Eutrophication ◼ Eutrophication occurs when fertilizers, animal wastes, sewage, or other substances rich in nitrogen and phosphorus flow into water ways, causing extensive algae growth. ◼ The algae use up the oxygen supply during their rapid growth an d after their deaths during the decaying process. ◼ Other organisms in the water suffocate. ◼ Eutrophication is a natural process, but human activities have ac celerated the rate at which it occurs. Biodiversity Eutrophication ◼ Eutrophication is the accumulati on of nutrients in aquatic ecosyst ems. ◼ It alters the dynamics of a numb er of plant, animal and bacterial populations; thus, bringing abou t changes in community structur e. ◼ It is a form of water pollution an d like all other forms of pollution is the result of human activities i nfluencing ecological cycles. ◼ The nutrient enrichment of an aq uatic ecosystem. Pritchard, D.W. 1967. What is an Estuary: Physical viewpoint. In Estuaries. Publication # 83. AAAS, Washington, D.C. Biodiversity Eutrophication ◼ Natural Eutrophication -- a process that occurs as a lake o r river ages over a period of hundreds or thousands of year s. ◼ Cultural Eutrophication -- a process that occurs when hu mans release excessive amounts of nutrients; it shortens t he rate of aging to decades. Pritchard, D.W. 1967. What is an Estuary: Physical viewpoint. In Estuaries. Publication # 83. AAAS, Washington, D.C. Biodiversity Natural Eutrophication ◼ Lake classification bas ed on nutrient content and production of orga nic matter. Oligo- nutrient poor; Meso- middle nutrient; Eu- nutrient rich. Pritchard, D.W. 1967. What is an Estuary: Physical viewpoint. In Estuaries. Publication # 83. AAAS, Washington, D.C. Biodiversity Cultural Eutrophication ◼ The addition of excess nutrien ts from a variety of sources res ults in the rapid aging of aqua tic ecosystems. ◼ During this process the specie s composition of the aquatic c ommunity changes. Pritchard, D.W. 1967. What is an Estuary: Physical viewpoint. In Estuaries. Publication # 83. AAAS, Washington, D.C. Biodiversity Pollution – Eutrophication Biodiversity Introduced Species ◼ Nonnative species that are either intentionally or unintentionally transported to a new habitat are known as introduced species. ◼ Introduced species often reproduce in large numbers because of a lack of predators, and become invasive species in their new hab itat. ◼ Introduced species are a worldwide environmental problem. An e stimated 40% of the extinctions that have occurred since 1750 are due to introduced species, and billions of dollars are spent every year in an effort to clean up or control the damage caused by intr oduced species. Biodiversity Why is it difficult to Protect Aquatic Biodiversity ◼ Rapid increasing human impacts, the invisibility of problems, cit izen unawareness, and lack of legal jurisdiction hinder protection of aquatic biodiversity. ◼ ◼ ◼ Human ecological footprint is expanding. Much of the damage to oceans is not visible to most people. Many people incorrectly view the oceans as an inexhaustible resource. Biodiversity Protecting and Sustaining Aquatic Biodiversity ◼ Laws, international treaties, and education can help reduce the p remature extinction of marine species. ◼ Since 1989 the Bangladesh government has required offshore shri mp trawlers to use turtle exclusion devices. ◼ Sea turtle tourism brings in almost three times as much mone y as the sale of turtle products. Biodiversity Protecting and Sustaining Aquatic Biodiversity ◼ Six of the world’s seven maj or turtle species are threaten ed or endangered because o human activities. Biodiversity Protecting and Sustaining Aquatic Biodiversity ◼ Fully protected marine reserves make up less than 0.3% of the wor ld’s ocean area. ◼ Studies show that fish populations double, size grows by almo st a third, reproduction triples and species diversity increases by almost one fourth. ◼ Some communities work together to develop integrated plans for managing their coastal areas. ◼ ◼ ◼ ◼ ◼ ◼ Develop unified national policy. Increase budget for ocean research. Centralize the National Oceans Agency. Set up network of marine reserves. Reorient fisheries management towards ecosystem function. Increase public awareness. Biodiversity Managing and Sustaining Fisheries Biodiversity ◼ There are a number of ways to manage fisheries more sustainable and protect aquatic biodiversity. ◼ Some fishing communities regulate fish harvests on their own and others work with the government to regulate them. ◼ Modern fisheries have weakened the ability of many coastal c ommunities to regulate their own fisheries. Biodiversity Solutions Managing Fisheries Fishery Regulations By catch Set catch limits well below the ma ximum sustainable yield Use wide-meshed nets to allow escap e of smaller fish Improve monitoring and enforcem ent of regulations Use net escape devices for sea birds and sea turtles Economic Approaches Ban throwing edible and marketable f ish back into the sea Sharply reduce or eliminate fishing su bsidies Charge fees for harvesting fish and sh ellfish from publicly owned offshore w aters Certify sustainable fisheries Aquaculture Restrict coastal locations for fish farms Control pollution more strictly Depend more on herbivorous fish species Protected Areas Establish no-fishing areas Establish more marine protected areas Rely more on integrated coastal management Consumer Information Label sustainably harvested fish Publicize overfished and threatened species Nonnative Invasions Kill organisms in ship ballast water Filter organisms from ship ballast water Dump ballast water far at sea and replace with deep-sea water Biodiversity and Conservation Thank You Very Much
