Biodiversity decline Flashcards
How many species go extinct/year?
- Decline by 60% from 1970-2014.
- Up to 0.01% (100 000) species go extinct each years.
- Decline is particularly pronounced in the tropics
- Up to 75% loss of insect biomass in protected areas.
What about parasites and biodiversity decline?
- 40% of living animals are parasites
- None of them are protected
- Important links in foodwebs, high amount of biomass
- Parasites are often excluded of biodiversity studies
- Ex of tasmanian devil : breeding programs in captivity -> but parasite control. Some parasites can only live on this devil.
What are some major drivers of biodiversity loss?
- Land use
- Climate change
- N deposition
- Biotic exchange
- Atmospheric CO2
- Urbanisation (ex: bangalore in india=> growth since 1970…)
However, different for different temperature zones/ecosystems. Ex in lakes, biotic exchange is major. In tropical, Temperate and Mediterranean zones, land use is major. In artic= climate.
What is the major driver to diversity loss when looking at species?
In general more habitat loss
For fish and mammals=> exploitation also big part.
Name some examples of land use intensifications and their impact
Excessive application of fertilizers
- Pollution of water, air, soil
- Human health issues
- Costs of N-losses are 70-320 billion euro/year, and the costs are larger than direct economic benefits from N-usage
Excessive usage of pesticides
- Neonicotinoids have a lethal and sublethal effect on wild and honey bees
- Sublethal effects : means that it affects health , behavior and reproduction of beneficial species
- Glyphosate: loss of arable weeds in fields and grasslands, loss of associated insects and soil fauna, declines in amphibians
Homogenization of cultural landscapes
- MOST IMPORTANT DRIVER OF BIODIVERSITY DECLINES
- Refered to by 80% of all articles on insect declines
What are some major reasons for land use intensification or homogenization of landscapes?
- Land use expantion and intensification in Europe in 20th century
- Green revolution
- Recently: bioenergy, rising prices for land
How is urbanization affecting biodiversity? (pollination)
Higher pollinator activity in Natural and semi natural areas
However, higher pollinator diversity in urban sprawl than in agricultural landscapes.
In urban cities, diversity further decreases.
Name an example of impact of climate change on biodiversity
Northward shift of butterfly distribution in the 20th century in UK.
Around 100 years ago=> less habitats. And now, more and more suitable habitat.
Also, warming favors light colored insects.
- Dark colored insects=> favored in cooler climates
- Light-colored species in warmer climates.
- ex = lady beetles… heat up faster when darker in colder climates
What are some key ecological footprints related to human footprint?
Increase in different key ecological footprints
- Grazing land
- Fishing grounds
- Forest product
- Cropland
- CARBON => one of the biggest
What are some of the main consequences of biodiversity losses?
- Decreased pollination and dispersal of seeds
- Decrease in a lot of different ecosystem services (go see slides…)
Why aren’t reserves enough?
- Even reserves are under immense pressure of biodiversity decline, and greatly deteriorating.
- (study from laurance; 50% of reserves= serious decline)
- Some reserves are succeeding, and indicate promising biodiversity outcomes, but even thses have issues with exotic plants and disturbance-favouring pioneer plants
- Negative outcomes inside a reserve (decrease population growth, decrease forest cover etc.), there are similar development outside of the reserve of protected areas.
- Env drivers inside reserves strongly correlate with those outsie reserves, even for trends like forest cover and road expansion
Should we protect biodiversity only through reserves?
No, as show in study from Laurance et al. 2012, drivers inside reserve strongly correlates with those outside of the reserve.
=> therefore reserves are not enough, and so is land-sparing (spare piece of land)
- Integration of strict protection (land-sparing) with diverse landscape matrix (land-sharing) is needed
=> land-sharings and sparing=> creates connectivity in landscapes
Describe integrative approaches for biodiversity protection ?
Land-sharing/sparing approach to increase connectivity of landscapes
Connecting:
- Protected areas with agricultural land
- Shared landscape elements with agriculture
- Exchange between spared and shared land
What is a consequence of biodiversity loss on human health?
Zoonosis
- Disease transmission from animals to humans => closer
- More diversity, less prevalance of diease in baths (study from Cottontail et al. 2009)
What is the dilution effect?
Idea is that intact habitat with high biodiversity => reducing the risk of disease spread, while habitats with low diversity have an increase risk of disease spread=> contact rate between individuals is increased => risk of infection is also increasing.
Increase diversity =
- Low host density (N)
- Low contact rates
- Low pathogen transmissibility
Leans to => low disease transmission and prevalence
Can be vs amplification effect…
