concept of biodiversity Flashcards
scale of biodiversity
not evenly distributed
50% in tropical rainforests due to the equatorial climate
varies on a local scale..
farmland has less biodiversity than a wetland ecosystem
measuring biodiversity
species richness: total variety of species in one area
living plant index: global measure of biodiversity and indicator for biodversity change on a global scale
global trends in biodiversity
declining on a global scale
LPI: 58% decline between 1970-2012
varies between regions
mass extinction events: last was 66 million years ago in the cretaceous period
causes of biodiversity decline
anthropogenic and natural causes
anthropogenic causes of BD decline
land use change
deforestation
drainage of wetlands
overexploitation
natural causes of BD decline
climate change
invasive species
pathogens
local trends in biodiversity
– UK: decline of 13% of wildlife species since 2019
– 0.0022% of the GDP was spent on biodiversity and conservation research development in that same year
– higher in areas being exploited for human development
cause - land use change
impermeable urban surfaces - increase surface run off
fragment habitats and destroy species habitats
reduces their ability to sustain their population sizes
cause - deforestation
removal of key habitats, food, and shelter
fragmentation - leads to genetic isolation
affect microclimate - impact the nutrient cycle and ability of bacteria to decompose and return nutrients to the soil
soil erosion - reduces productivity and change in species composition
reduction in ecosystem services such as providing goods (food, fuel, water, tourism) and social services (pleasure and mindfulness)
drainage of wetlands
25% of species threatened with extinction
dependent on by 40% of species which is over 100,00 wetland species
coastal wetlands like mangroves and reefs are some of the most ecoloicaly diverse habitats
87% of wetlands have been lost since the 1700s and are vanishing 3x faster than forests
over exploitation
harvesting species from the wild at a rate faster than natural populations can recover
– logging: reduces habitats and increases fragmentation
– agricultural soil depletion: reduces nutrients available for natural species and leads to them being outcompeted
why is biodiversity declining
influencers (human population growth pressure and increasing consumption) influence the primary drivers of biodiversity loss
cause - climate change
additional 4 ggt of Co2 in the atmosphere every year - global average increased by 47% since 1988
40% of ice loss since 1960
positive feedback loops have accelerated the warming at unprecedented rates
increased wildfires – 11.5 million ha of taiga forest have burnt this decade – Yakutsk has been warming 2.5x more than the global average – wildfires caused an ‘air apocalypse’
cause - pathogens
specific climate viruses will be exposed to a greater sphere of influence – increasing potential infection rates
climate change also weakens ecosystem services so protection and vulnerability decrease
cause - invasive species
outcompete native species - highly adapted and have no natural predators in new habitats
eg: grey squirrel native to the USA brought over to the UK which is outcompeting for limited resources the natural red squirrel who is less adapted and declining in population numbers
change the ecosystem distribution by predation of natural species
physical impacts of biodiversity loss
extinction of species and the following extinction of species that rely on them
less carbon capture which increases the enhanced greenhouse effect
impacts on the water cycle – floods and droughts – less water vapor returning to the atmosphere via evapotranspiration
human impacts of declining biodiversity
reduce food supplies (disappearance of pollinators) leads to hunger and starvation
reduce access to clean air and water supplies
loss of potential medicines
why is there a need for sustainable ecosystem development
global human population is growing – strains ecosystem services (products are getting harder to share leading to inequalities)
using more land for urban developments increasing pollution and depleting resources
Frieburg and ecosystem sustainability
40% of the city is forested
56% of forests are nature conservation areas
local river is unmanaged and allowed to flow freely
only native shrubs are planted – planted 44,000 trees in parks and streets
all of these allow the city to work symbiotically with the natural environment – the ecosystem provided essential services for the human population and in term, humans sustainably manage and work with the ecosystem, making sure not to overexploit or deplete the natural resources
