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Landscape Ecology Sample Test mosaic: idea of a h…

Landscape Ecology
Sample Test

mosaic: idea of a holistic landscape created from the interaction of different landscape components. Streams, forest stands, crop fields, roads, ponds and meadows are some examples of these landscape components.
boundary:
connectivity: spatial continuity of a habitat or cover type across a landscape.
matrix: background cover type in a landscape, characterized by extensive cover and high connectivity; not all landscapes have a definable matrix.
patch: surface area that differs from its surroundings in nature or appearance.
corridor: relatively narrow strip of a particular type that differs from the areas adjacent on both sides.
edge: portion of an ecosystem or cover type near its perimeter and w/in which environmental conditions may differ from interior locations in the ecosystem; also used as a measure of the length of adjacency between cover types on a landscape.
metapopulation: composite set of local populations (subpopulations) w/in some larger area, where typically migration from one local population to some other patches is possible.

1. Give one important reason that the diversity of plants and animals is often lost in smaller patches. Briefly explain in two or three sentences.
As patch size decreases, so does usable land area. With smaller land area, there is more competition between plant and animal species to utilize the land. Only so many plants can physically exist in a given area; there are several models to explain competition: direct competition, whereby one species completely takes over; and reaction-diffusion models, whereby several species coexist w/ one or two species precariously maintaining competitive advantage until some natural event shifts favor to a different species.
As patch size decreases, edge increases. This exposes more interior animal and plant species to conditions they would normally not encounter, and therefore greatly reduces their habitat. These species must either adapt, move, or face extinction.

2. Give one important reason that patch edges change their characteristics and/or location over time. Briefly explain in several sentences.
Patch edges may change characteristics due to climate change. A shift in temperature may result in not only hotter or colder conditions, but also may change moisture, wind, and subsequently access to solar radiation. These altered conditions may benefit certain species and be detrimental to others, altering the balance of plant and animal species.

3. A patch with little interior habitat might have what kind of shape? Draw an example. Briefly explain why this is important in landscape ecology.

Certain plant and animal species thrive on interior habitat, and will face drastically reduced population or extinction if faced w/ edge conditions.

4. How could you measure the connectivity of a corridor? Why is this important to do?
Track migration of specific indicator animal species or keystone species between connected patches. While some species require a corridor for to successfully locate food and mates in other patches (corridor serving as life line in an altered habitat), other predatorial species may utilize the corridor in order to venture to previously unexplored patches and find unprotected prey.
Definition:corridor: relatively narrow strip of a particular type that differs from the areas adjacent on both sides.

5. How can a corridor serve as a source for some objects and a sink for others? Give an example of each.
metapopulation: composite set of local populations (subpopulations) w/in some larger area, where typically migration from one local population to some other patches is possible.
A corridor may serve as a source when edge conditions favor the proliferation a certain species. It may also provide a means by which a species may move to another patch where it may proliferate. On the other hand, the edge condition presented by a corridor may not contain the resources necessary to sustain a population in a given patch, resulting in population declination. A corridor may also allow the introduction of a predator species that will result in a diminished prey population.

6. You are the newly hired landscape ecologist in the Xyz County Planning Office (congratulations!). In the first office meeting, you are asked to explain what is meant by “edge effect” and why it is of oconcern for environmentally sound planning. In the space below, provide your answer (about 2 paragraphs or 15 sentences). Feel free to draw a figure(s) if that would be helpful.
edge: portion of an ecosystem or cover type near its perimeter and w/in which environmental conditions may differ from interio locations in the ecosystem; also used as a measure of the length of adjacency between cover types on a landscape.
Edge effect occurs at the border between 2 distinct patches. It can have both abiotic and biotic causes and effect, meaning that it can result from naturally occurring or man-made phenomena (road building, construction, weather – abiotic) or from the interaction between plants, animals, or microorganisms (biotic). The edge effect defines how these 2 patches interact – for instance, if a road is placed through a forest, the forest edge will be inhabited by plant species that prefer more direct sunlight (as opposed to living under the cover of forest canopy) and animal species prefer more open space or the food provided by the edge plant species. This edge is neither distinctly ‘forest’, nor is it obviously road. It inhabits a stage of in-betweeness that buffers between 2 distincly different patches.

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