landscape ecology

landscape ecology

considers the spatial arrangement of habitats at different scales and examines how they influence individuals, populations, communities, and ecosystem

landscape ecology considers how natural systems are affected by

patchiness, habitat total area, and connectivity of habitat patches

why are lanscapes patchy

fragmentation (natural or anthropogenic) and heterogeneity (result in patches of similar and dissimilar habitats) can effect diversity

long time ago that influenced habitat patchness 

eskers, remains of rivers underneath glaciers

legacy effects

a long lasting influence of historical processes on the current ecology of the area

when you go to bigger patches what do you see?

greater species richness and slope is highly repetiable across different areas 

why does slope species go stright

max out species on island or counted all species on island

gamma diversity

the diversity (usually calculated as an index) of the regional species pool (species richness and eveness in largest area measuring)

all of the species in the region are reffered to as

the regional species pool (relatively large area)

alpha diversity

species diversity index within a relatively small area and in a more homogeneous habitat, aka local diversity

beta diversity

comparison of diversity beween habitats, usually measured as the species change between habitats (ex. different stream areas)

if two habitats have high beta diversity together what are they

very different (higher the number the more unique species)

as population size increase what?

the probability of extinction in a certain amount of years decreases

greater habitat areas can support what

greater sizes of populations (lower risk of extinction)

small island with no predators had what 

herbivors went out of control

what leads to differential extinction

species interactions (predation, competition, mutualism, etc) play out as normal and casading effects in communities 

connectivity of habitat patches

habitat corridors

stepping stones

small intervening habitat patches that dispersing organisms can use to move between large favorable habitats

island biogeography

habitat patchiness, size, and connectivity along with the theory from population ecology can explain the patterns of diversity seen across communities on a large scale

when you wipe out the species on the island what happens?

number kinda stays the same but not the same concentration of species

what is the hypothesis

diversity should be related to the size and isolation of habitats within a patchy landscape

equilibrium theroy of island biogeography

the number of species on an island reflects a balance between the colonization of new species and the extinction of existing species

what if more species are present 

more could go extinct (negative species interaction)

edge effects

change in population sizes, species richness, or other aspects of the ecology of individuals, populations or communities at the interface of 2 habitat types

in terms of reserves are edges good?

no habitat on edges are different from interior trying to reserve

why is edge good in small areas

one section may be fine if its into smaller reserve than bigger if something happened 

why are so many species in the tropics

could be greater speciation toward equators and lower extinction

energy-diversity hypothesis

habitats with higher amounts of energy (proxy, potential evapotranspiration, PET) can support more species 

what can energy- diversity hypothesis do

support larger populations (less extinction) and accelerate rate of evolutionary change (more speciation)

what is another explanation for species in the tropics

earth history, europe has not yet reached its new equilibrium state following the last glacial maximum (tree ranges have not yet recovered)