Landscape Ecology

What are the four origins of patches?
1) Remnants (areas remaining from an earlier more extensive type, such as woodlands or agricultural areas.

2) Introduced (such as a new suburban development in an agricultural area)

3) Disturbance (a burned area in a forest or a spot devastated by a windstorm).

4) Environmental Resources (wetlands in a city, or oases in a desert).

Speak about patch size, location, and occurrence.
Patches can be as large as a national forest or as small as a single tree. They may be numerous in a landscape, or scares (such as a desert oasis). The patch’s location can be beneficial or harmful to the overall ecosystem (a patch of forest in agricultural land would be beneficial, but a landfill next to a wetland would be harmful.
How does a larger edge size effect species?
A slightly greater number of edge species, and higher populations of those species.
How does a reduced interior habitat effect species?
It leads to reduced population size of these species, which are often of conservation importance.
What is a general benefit of large patches?
Support interior species, provide core habitat, allow natural disturbance regimes, protect groundwater quality, protect downstream areas from hydrologic effect
Explain local extinction probability.
A larger patch normally has a larger population size of any given species than smaller patches, making it less likely for the species to go extinct in the local patch. Note: in this context “extinction” does not refer to complete, worldwide extinction, but rather to localized, patch extinction.
Name two reasons local extinction might occur.
If a patch is small, or if a patch has low habitat quality.
How does patch size relate to habitat diversity?
A larger patch is more likely to have more habitats, resulting in a greater number of species than a smaller patch.
In what scenario would dividing a large patch be beneficial?
If there was a disturbance in one area of the patch, creating a barrier to disturbance would decrease the spread of the disturbance.
Name some benefits of large patches on the ecosystem.
Large patches of natural vegetation protect aquifers and stream networks, sustain viable populations of interior species, provide habitat and cover for large vertebrates, and permit near-natural disturbance regimes.
Discuss small patch benefits.
Small patches can act as stepping stones for species movement across stretches of matrix. If large patches are absent, they can contain some uncommon species, but can sometimes be unsuitable for a species. Small patches work best as a supplement to large patches.
What are the effects of habitat loss on species?
Reduction in population size, and reduction in habitat diversity.
How would a species live in a grouped patch?
Some species can survive in a cluster of smaller patches, which while are inadequate on their own, are suitable when combined.
How should patches be selected for conservation?
1) Contribution to the overall system — how well the location of the patch related or links to other patches within the landscape.

2) Unusual or distinctive characteristics — whether the patch has any rare, threatened, or endemic species present.

How does structural diversity effect the quality of an edge?
Higher structural diversity, either vertical or horizontal, are richer in edge animal species.
What side of a patch is the edge the widest?
Edge width varies around a patch, with the widest edges on sides facing the predominant wind direction and solar exposure.
How does an edge act a as a filter?
Patch edges dampen the influence of the surroundings on the patch interior.
How does edge abruptness (hardness) effect movement.
A harder, more abrupt edge increases movement along that edge whereas a softer edge favors movement across (through) an edge.
What are the ecological benefits of of a curvilinear boundary?
Less soil erosion and greater wildlife usage.
How do coves and lobes increase species diversity?
By providing greater habitat diversity than a straight edge.
How are interior and edge species effected by convoluted patches?
Edge species are slightly increased, but interior species sharply decrease.
Does a convoluted patch interact more or less with its surroundings?
More. The more convoluted the patch, the more interaction (can be positive or negative) between the patch and the matrix.
What is the best shape for a patch?
A “spaceship shape”, with a rounded core for protection of resources, plus some curvilinear boundaries and a few fingers for species dispersal.
What are the 5 major functions of corridors and in controls their quality?
Habitat, conduit, filter, source, and sink. The wider and more connected the corridor is, the better these functions are.
How do structural and floristic similarity effect the area between corridors and large patches?
It is preferable for structure and floristics to be similar between corridors and patches, though it is often more important to have structural similarity than floristic similarity to encourage movement between large patches.
What is the best layout for stepping stone patches?
A cluster of patches that provides alternate or redundant routes while maintaining an overall linearly-oriented array between large patches.
Explain the nutrient spiraling concept.
As nutrients such as Nitrogen and Phosphorus are washed over the land, they are carried and deposited into streams. When flow increases, they are carried and deposited downstream. This cycle of movement and deposition or settlement can repeat several times. As nutrients are often attached to particulates and soil, preventing erosion will also reduce nutrification.
What are key ecological processes that affect the necessary width for river/stream corridors?
Movement along the corridor, movement across the corridor, and habitat resources available (and needs of species present)
What effects do straight corridors (human made, such as railroads, powerlines, etc.) have on a matrix.
They can ask as barriers that subdivide populations of species into metapopulations. They also act as conduits for disturbance tolerant species (invasives) and are home to erosion, sedimentation, exotic species, and other human effects on the matrix.
Briefly describe the benefits of networks.
Networks are composed of nodes and links, and some (but not all) have hierarchies. When networks are well connected, they can improve population stability (both through a larger gene pool and multiple routes allowing dispersal) and decrease isolation. A variation in mesh size and link width can help as well. High circuitry and curvilinearity increase structural and species diversity.