17 human impact on env 1 deforestation overfishing and conservation

conservation

species becoming extinct and/ or endangered

why do species become extinct or endangered

• natural selection: species cant adapt to changing conditions (human activity) and reproduce successfully

• habitat loss: deforestation, drainage & wetlands, hedgerow removal

• non-contiguous population: small isolated groups cant interbreed reducing genetic biodiversity

• overhunting: overfishing

• pollution: PCBs

• introduced species: can outcompete

conservation

the protection, preservation management and restoration of natural habitats and their ecological communities to enhance biodiversity while allowing for suitable human activity

2 types of conservation

in captivity and in wild (acts as a living gene book)

ways of conservation

• gene pools (IW IC)

• nature reserves

• sites of special scientific interest (SSSIs)

• special areas of conservation (SACs)

• legal protection and habitat management (above all IW)

• captive breeding programs

• sperm bank

• seed banks

• rare breed societies (above all IC)

monoculture

the growth of large numbers of genetically identical crop lants in a desired area

this provides only one habitat, so reduces species diversity, where if crops are mixed there’ll be more animals and microhabitats

2 types of forest management

• coppicing: cutting trees close to the ground and leaving them for several years to re grow

increased sustainability and variety of habitats develop, favouring diverse wildlife

• selective cutting: felling only some trees that are ‘adult’ leaving others in place

• prevents soil erosion and maintains nutrients in the forest soil and minimises the amount of soil that is washed by nearby waterways

effects of overfishing

implications for the rest of the food chain. risks of decreased pop

methods of regulation with overfishing

• large mesh nets allow smaller baby fishes to espace and reproduce

• fishing quotes limits the mass of fish that can be caught, prevents overexploitation

• exclusion zones/closed sections ban fishing during breeding season so pop. regrows

• laws limiting days at sea reducing fishing pressure

why can fish farming be problematic

disease spread: harm other marine organism

pollution and eutrophication: disrupts ecosystem

env. toxins: farmed fish can contain higher concetration of pollutants such as PCBs