threats to biodiversity

what are the direct threats

• Food 

• Fashion

• Entertainment

• Furniture and Ornaments

• Traditional Medicines

what are the indirect threats

• Eradication of predators and competition

• Changes to abiotic factors

• Changes to biotic factors 

• Introduced species

• Habitat Destruction 

methods of fishing that threaten fish

• mesh sizes - juvenile fish can’t fit through

• Bottom / demersal trawling - towed nets to catch fish and other marine species living on or close to the seabed.

why is bottom / demersal trawling bad

• destroys their habitats on the seafloor

• causes significant damage to coral reefs and seagrass beds

• leads to high levels of bycatch, where non-target species like young fish or endangered animals are caught unintentionally and can be injured or killed in the process

what entertainment is a threat to

• pets by trade - decreases biodiversity, ecological niches, and can narrow gene pool

• exotic plants

• aquarium animals

examples of furniture and ornaments which threaten biodiversity

• trees - pianos, furnitures

• elephants / rhinos - ivery

deforestation impacts

• loss of habitats

• changes to microclimates

• creates a lack of D.O.M

traditional medicines examples

• tiger claws - alcoholism, sedatives, skin diseases

• rhino horn - nosebleeds, small pox

• seahorses - infertility, baldness, arthritis

what causes changes in abiotic factors indirectly threatens biodiversity

• Human activities may alter but not destroy a habitat

• Organisms may not be adapted to the new conditions, as they are outside their range of tolerances

abiotic changes which have been indirectly threatened

• temp

• water turbidity

• physical damage

• dissolved oxygen

• pH

• water availability

how water availability has been indirectly threatened

• greenhouse gases (CO2, NOx) absorbs IR and converts them into heat. - more heat = more KE = increased evaporation. this will condense but wind will change where the cloud condenses meaning less fresh water in the wet lands

• urbanisation - housing companies building houses over wetlands

how dissolved oxygen has been indirectly threatened

• bacteria in sewage water aerobically = less O2

how temp will indirectly threaten biodiversity

• GGC will change distributions of species - move for new habitats

• hot effluent water will increase the growth rates of aquatic vegetation - thermal pollution

• temp - dependant sex determination in species of reptiles

how pH will indirectly threaten biodiversity

• acidic conditions can be used by mine drainage water, pollutant gases from burning fossil fuels and smelting metals

• mine drainage water

  • in spoil heaps = FeS, O2, H20 which will react together to form sulphuric acid which has a pH of 4

• low pH alters the shapes of enzymes, denaturing them

• crayfish live in high pH because their shells / exoskeletons are made from Ca⁺ which has a high pH

how water turbidity will indirectly threaten biodiversity

• ploughing (increasing soil erosion), mining and dredging may increase water turbidity

• this reduces the efficiency of photosynthesis and filter feeding

how physical damage will indirectly threaten biodiversity

microplastics - never completely degrade - photodegrade instead- into smaller pieces which can be ingested. if small enough it can get into bloodstream

biotic changes which will indirectly threaten biodiversity

• eradication of predators

• introduced species

• habitat destruction

how eradication of predators will indirectly threaten biodiversity

Predators can increase diversity in communities by preying on competitive dominant species or by reducing consumer pressure on foundation species.

how introduced species will indirectly threaten biodiversity

• Indigenous species are adapted to the abiotic and biotic conditions of their surroundings

• Introduced species may have adaptations that give them a greater chance of survival

introduced species examples

• american mink threatens european water vole

• signal crayfish threatens white clawed crayfish as they carry a pathogen that white clawed crayfish aren’t immune

• grey squirrels threaten red squirrels

how habitat destruction will indirectly threaten biodiversity

• mining

• urbanisation

• deforestation

• agriculture

• reservoirs