Lecture 7 Flashcards
why is patch shape important?
Essentially patch shape can influence species composition and structure
define contrast:
is the degree of difference and or the abruptness of the transition between a patch and the adjacent landscape elements
in 2 studies they found that deer mouse really liked edge habitat, but in another they found they liked interior, what does this tell you?
context really does matter!
species that increase/decrease in abundance with patch size or are found in large/small patches are available are….
area-sensitive species
what is the shannows diversity index?
probability of barriers present within patch
circle is less probability and oval is more
define patch edge:
is the band aound a patch that is environmentally different from the interior, giving rish to a different spcies compliement and abundance in the interior
based on studies of the SLOSS debate what is the general conclusion?
habitat fragmentation may not matter to species diversity…. and this is stupid thing to argue about holy shit. Also many studies were just comparing oen species and not a community,
environmental dynamics and spatial dispersal must be considered.
several small may be optimal for long term species only if the species range increases with the number of patches.
patch size tends to be positively correlated with ———-
species richness and diversity
probability it is functionng as a corridor for species movement
circle is less and oval is more
patch size can infuence other components of the ecosystem:
- quality of remnant patches 2. nutrient cycling 3. interactions between predators and prey
explain island biogeography theory:
species diversity increase with area due to haitat diversity, however distance from mainand is a negative thing with diversity. But we will see increase as the island ages.
why choose a single large reserve?
preserves intact communities
Better able to maintain viable populations that occur at low population densities such as large vertebrates
why is orientation important for dispersal of organisms and energy across the landscape?
if there is a direction for downslope there may by inhibition of erosion water and nutrient runoff and there also may be factors with prevailing winds.
effect immigration rate to the patch,
why several small?
size such as “what is large” is species dependent and it spreads the risk of catastrophic disturbance
define context:
the adjacent landscape elements in contact with a patch at a local scale.
calculate shannons equitability for each area.
what are the 4 differences in island patches and landscapes islands or patches?
- islands tend to be more or less permanenet; landscape patches have high turnover rates
- shrpness of edges on landscape patch is variable; edges may be more conducive to movement of spcies between the matrix and patches.
- matrix usually has high heterogenity on landscapes. Potentially many and diverse colonizing species in the matrix.
- Isolation is less in landscapes
species diversity?
more in circle and less in oval
calculate shannos diversity index?
what was the general results from arthropods in savannah patches study?
- species richness was greater in rectangles
- evennes was lower in connected patches
- beta diversity was higher in rectangles,
what are 3 design principles using IBG as a template?
- larger better than smaller
- if only several small reserve available they should be as close as possible
- if reserve are isolated connecting with corridors can improve their conservation
what is the SLOSS debate?
single large reserve or several small reserves? (same area)
calculate diversity and eveness for the different habitat types
actually do it, i don’t know the answers yet
what can IBG be applied to?
design of natural reserves
what is shannons equitability (evenness)?
what is the habitat richness?
4
species that do not respond to patch size are….
area-independent species
predation on dickcissel and eastern meadowlark ———– as patch size increases
decreases
alien plants tend to be found in interoir or on edges of patches?
edges
in one study they found that species richness ———– as we got more perimeter to interior ration
decreased
what is diversity based on
species richness (# of species) and species abundance (# of individuals of each species)
whats the difference between beta, alpha and gamma diversity?
alpha is diversity within an area
beta is diversity between ecosystems
gamma is diversity in total regional species pool
why is patch size important?
influence the amount of interior and the amount of edge.
edges can be defined as what?
in temrs of contrast
what are the steps of edge creations?
1st degree process responses- increase in productivity, nutrient cycling, decomposition, dispersal
1st degree structural responses- less canopy cover, tree density and biomass
2nd degree process responses- recruitment, growth, mortality, reproduction
2nd degree structural responses - spling density, understory cover
2md degree compositiona responses- changes in species composition
If there is a low perimeneter/edge ratio or high interior/edge ratio what are aspects of it
less length and therefores less interaction with matrix.
Less probability of barriers present within patch
Less funcioning as a corridor for species movement
more species divrsity
if there is a high perimeter/edge ration or low interior/edge ratio what are some aspects?
- more length and interaction with matrix
- Mor probability of barriers present within patch
- more functioning as a corridor
- less species diversity
context:
context is the setting or the adjacent landscape elements in contact with a patch at a local scale.
what is the bioconcetration factor or BCF
simple partitioning across lipid membrane in gills of fish
+ve correlation between BCF and what>
log Kow
bioaccumulation of chemicals comes from what?
- paritioning of chemicals across gills
- concentration coming from food
what is equations for log BCF?
