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<P><B>Edge Species</B> - plant or animal species which thrive on the edges of habitats such as a forest which provide them with access to cover and food sources. Examples include: sumac, white-tailed deer, and cowbirds.Definition of Edge Species courtesy of the University of Wisconsin at Stephens Point:</P>
<P class=r><A class=l onmousedown="return clk(this.href,'','','res','7','')" href="http://www.life.umd.edu/biology/faculty/fagan/lectures/edge_lecture.ppt">Edge Effects and Fragmentation</A> - PowerPoint Lecture on Edge Effects - William Fagan, University of Maryland</P>
<P class=r><A href="http://en.wikipedia.org/wiki/Edge_Effects">Wikipedia entry on Edge Effects</A></P>
<P align=left>Below: A discussion on edge effects from <A href="http://edis.ifas.ufl.edu/pdffiles/fr/fr07200.pdf">Chapter 8 of Enriching and Managing Urban Forests forWildlife </A>from "Restoring the Urban Forest Ecosystem", By Joseph M. Schaefer, Professor, Dept. of Wildlife Ecology and Conservation and Director, Center for Natural Resources, Cooperative Extension Service, Institute of Food and Agricultural Sciences, University of Florida. June 2000. Please visit the EDIS Web site at <A href="http://edis.ifas.ufl.edu/">http://edis.ifas.ufl.edu</A> </P>
<P align=left><STRONG>Edge Effects</STRONG> - One obvious characteristic of urban forests is the sharp contrast between various land uses/vegetation on these sites. Many human-made, sharp edges or borders between vegetation types are found in this type of landscape. These sharp edges cause many problems for wildlife and their habitats. Human-modified areas surrounding a forest fragment are usually altered into earlier successional stages</P>
<P align=left>These areas are attractive to pioneering species that invade several hundred meters into the adjacent forest fragment and alter the plant species composition and relative abundance which in turn affects the suitability of the habitat for various wildlife species. Along forest edges, avian brood parasites (cowbirds), nest predators (small mammals, grackles, jays, and crows), and non-native nest hole competitors (e.g., starlings) are usually abundant. Cowbirds feed in open areas and lays their eggs in other species' nests found along forest edges. Many birds cannot distinguish this foreign egg from their own and devote all of their energy to raising the young cowbirds. The eggs of the host species are either removed by the adult cowbird or are pushed out of the nest by the more aggressive cowbird nestling. The result is cowbird numbers increase at the expense of the host species.</P>
<P align=left>A field-forest edge also attracts a variety of open-nesting birds, but such an edge functions as an "ecological trap." Birds nesting near the edge usually have smaller clutches and are more subject to higher rates of predation and cowbird parasitism than those nesting in either adjoining habitats (Brittingham and Temple 1983). A general principle is that the greater the contrast between adjacent vegetation types, the greater the edge effect.</P>
<P align=left>Noise associated with construction, operation, and maintenance of developments can cause harmful impacts on wildlife. Animals that rely on their hearing for courtship and mating behavior, prey location, predator detection, homing, etc., will be more threatened by increased noise than will species that use other sensory modalities. However, due to the complex interrelationships that exist among all the organisms in an ecosystem, direct interference with one species will indirectly affect many others.</P>
<P align=left>Any forest tract has a "core area" that is relatively immune to deleterious edge effects and is always far smaller than the total area of the forest. Relatively round forest tracts with small edge-to-interior ratios would thus be more secure, whereas thin, elongated forests (such as those along unbuffered riparian strips) may have very little or no core area and would be highly vulnerable to negative edge effects.</P>
<P align=left>Edge effects have been shown to negatively impact wildlife species within at least 300 feet of forest boundaries (Janzen 1986, Wilcove et al. 1986). Studies of nature reserve boundaries have provided data that support the need for buffer zones of decreasing use outside reserve boundary (Adams and Dove 1989). The core of these areas must be protected from cats, dogs, human activities, noise, predators, exotic competitors, parasitism and other detrimental effects of development.</P>
