Biodiversity and Conservation Biology Flashcards
species richness
the number of species in a defined area/community
one of the strongest patterns in ecology is the latitudinal diversity gradient
latitudinal diversity gradient
for most groups, there are more species at low latitudes (closer to equator) than high latitudes (closer to poles)
multiple, non-mutually excessive hypotheses
species evenness
the relative abundance of each species in a defined area/community
can be incorporated into estimates of diversity
species diversity
incorporates both richness and evenness
endemic
found in a particular area and nowhere else
species endemism
high values often in small and/or isolated habitat patches
- islands (e.g. Galapagos)
- mountains (e.g. Eastern Arc Mountains)
- isolated forests (e.g. Atlantic forest)
genetic diversity
total genetic information within a defined population, species, or community
new sequencing technology especially effective at measuring microbial and fungal diversity
- environmental sampling or metagenomics
- collect massive amounts of DNA or RNA sequences soils or water
- detect species (genomic) or functional (expressed genes) diversity
taxonomic (phylogenetic) diversity
some branches in the ToL of species rich and others are species poor
conserving species poor branches increases taxonomic diversity
-includes phylogenetic distance between species
biodiversity hotspots
areas with exceptional concentrations of endemic species and high levels of habitat lost
habitat destruction/degradation is one criteria for defining hotspots
pioneered by Norman Myers
criteria:
- at least 1500 (0.5%) of world’s 300,000 plant species as endemics
- lost 70% or more of its historic (traditional) vegetation
34 hotspots
- 2.3% land area
- > 50% of all plant species and >42% of all vertebrate species
criticisms
- focus on endemism
- focus on historic rather than current loss (Amazon, Congo, and New Guinea rainforests do not qualify)
- what about boreal and tundra biomes
Atlantic forest
variety of tropical forest ecosystems in SE Brazil
high levels of endemism
estimated 15% of historic range
habitat destruction
mostly due to human land use
-logging, dams, dredging, livestock, agriculture, mining, development
deforestation
habitat degradation
reduction in the quality of a habitat caused by human activities
use of artificial light at night and creating traffic noise
more degraded “edge” habitat
- more exposure to light and wind
- higher likelihood of invasion by weedy species
multiple factors and threats to biodiversity
habitat lost
invasive species
over-exploration
pollution
native species interactions
natural causes
climate change
loss of polar and high altitude habitats
change of coastal habitats due to sea level rise
difficulty for some species to shift ranges
increased frequency/intensity of storms and droughts
increased sea temperatures and acidification
-coral bleaching
invasive species
exotic species that grows to a large population size and compete successfully with native species
estimated 58% of extinctions in last 500 years primarily due to invasive species
mediated by global trade and travel
exotic species
non-native species introduced to a new area
overexploitation
unsustainable removal of wildlife form the environment for use by humans
major threat for marine species
hunting bushmeat
animal products
pet trade
e.g. Atlantic cod
