This paper looked at predation rates on ground nests in forest fragments to determine if predation is influenced by distance to farmland-forest edge. The three year study showed that predation rates were lower in forest habitat than farmland-forest edge or farmland and that they decreased as the distance from farmland-forest edge increased. The main consequence of the increased predation rate near edges is a lower reproductive success in small as compared to large habitat fragments and in fragmented landscapes as compared to continuous habitats.
2. Burger, L.D., L.W. Burger, Jr., and J. Faaborg. 1994. Effects of prairie fragmentation on predation on artificial nests. J. Wildl. Manage. 58(2):249-253.
The authors examined predation rates on artificial ground nests in regards to prairie fragment size and closeness to woody cover in a tallgrass prairie ecosystem. Highest predation rates were observed in the smallest prairie sized fragments but proximity to woody cover was found to be a more important factor affecting nest predation rates. Management implications were found to include the purchase of larger prairies and the minimization of edge effects by reducing woody vegetation within prairies and along edges.
3. Burke, D.M., and E. Nol. 1998. Edge and fragment size effects on the vegetation of deciduous forests in Ontario, Canada. Nat. Areas J. 18:45-53.
Like many of the other edge papers one of the things this paper looked at was distance from edge effects. What was unique about the paper was that it looked at the microclimate changes between edge and interior and the penetration of alien species. One of the surprising results that the authors found was that a sharp gradient in light, soil moisture and soil temperature occurred within 5 m of the edge in both large and small woodlots.
4. Chen, J., J.F. Franklin, and T.A. Spies. 1992. Vegetation responses to edge environments in old growth Douglas fir forests. Ecol. Applic. 2(4):387-396.
The authors looked at the responses of tree stocking density, mortality, growth , and regeneration of three conifer species in old-growth Douglas-fir forests in relation to distance from edge of adjacent clearcuts. Canopy cover was found to increase significantly from the edge to interior, was found to occur rapidly, and variation in canopy cover was found to be higher near the edge. The maximum depth-of-edge influence was found to be a distance of 240 m from the edge.
5. Demaynadier, P.G., and M.L. Hunter, Jr. 1998. Effects of silvicultural edges on the distribution and abundance of amphibians in Maine. Conser. Biol. 12(2):340-352.
Physiological constraints, small homeranges and poor dispersal capabilities of amphibians along with a positive correlation to the quantity and quality of coarse woody debris, litter depth and moisture, understory vegetation and overstory canopy closure all suggest that structural habitat changes of induced forest edges are likely to have important effects on amphibian populations. Red-backed salamanders, wood frogs, and mole salamanders were all found to be sensitive to forest management practices. In addition red-backed salamanders and mole salamanders were found to be most abundant along forest interior portions of the edge gradient.
6. Essen, P., and K. Renhorn. 1998. Edge effects on an epiphyte lichen in fragmented forests. Conser. Biol. 12(6):1307-1317.
This paper is one of only a few that has looked at edge effects on a epiphytic lichen in a fragmented forest ecosystem. The authors found the following: abundance of the lichen was lower at the edges than interior, length of the lichen was significantly affected by both distance from edge and location, and maximum edge effects were found to extend 25-50 m into the forest. The authors further concluded that epiphytic lichens have a large potential as indicators of forest edge effects.
7. Fleming, K.K., and W.M. Giuliano. 1998. Effect of border-edge cuts on birds at woodlot edges in southwestern Pennsylvania. J. Wildl. Manage. 62(4):1430-1437.
This paper investigated the effect of border-edge cuts on avian species using edge habitat and involved vegetation sampling, bird counts, and nest location. Substantial differences in vegetation structure and composition were found between cut and uncut edges while no difference in avian species richness was observed between the two, although species assemblages were different. In addition, no difference in depredation rates between nests in border-edge cuts and uncut edges were found.
8. Kenkel, N.C., J.A. Hoskins, and W.D. Hoskins. 1989. Edge effects in the use of area polygons to study competition. Ecology 70(1):272-274.
" The Dirichlet tessellation is a subdivision of points in a plane such that each point has associated with it a polygonal area defining a region nearer to that point than to any other" (Kenkel et al. 1989). This paper points out a problem in the treatment of edge effects in studies that suggest that these polygons can be used to measure the area potentially available to an individual plant in a population and shows how to utilize an algorithm to exclude from consideration all polygons that are potentially influenced by individuals located outside the mapped study area. This exclusion is necessary due to the lack of information on the spatial distribution of individuals outside the study area.
9. Laurance, W.F. 1991. Edge effects in tropical forest fragments: application of a model for the design of nature reserves. Biolog. Conser. 57:205-219.
Tropical forest fragments ranging in size from 1.4 to 590 ha in size were sampled for indicator plants (5 genera and one structural class of disturbance-adapted plants). In addition, an index of canopy cover, subcanopy cover, logging intensity, and exposure to a cyclone that occurred in 1986 were measured. The Core-Area model was used to apply edge effect data in order to design nature reserves and determine the distance that edge conditions penetrate into the forest fragments.
10. Laurance, W.F., E. Yensen. 1991. Predicting the impacts of edge effects in fragmented habitats. Biolog. Conser. 55:77-92.
The authors developed a Core-Area Model to estimate the total area of pristine habitat contained in fragments of varying size and shapes and to predict the amount of unaltered habitat preserved within a hypothetical fragment for potential use in reserve design. The model was found to have some difficulty dealing with more circular fragments and was adjusted to account for this so that the final result was >96% accuracy for a perfect circle shaped fragment. Even with >96% accuracy for troublesome shapes like perfect circles the Core-Area Model is not applicable to all edge related phenomena (i.e., assessing human impacts in reserves or along boundaries or forest interiors that exhibit striking heterogeneity).
11. Lynch, J.F., and D.A. Saunders. 1991. Responses of bird species to habitat fragmentation in the wheatbelt of Western Australia: interiors, edges, and corridors. Pgs. 143-158 In: D.A. Saunders, R.J. Hobbs, and P.R. Ehrlich (eds.). Nature conservation 2: the role of corridors. Surrey Beatty and Sons, Australia.
This paper looked at the differences between reserve interiors, reserve edges, and reserve corridors or verges on bird populations. Results from the paper showed that an surprisingly high proportion of avifauna used the corridors as habitat, at least occasionally, however many species were so infrequently observed that their distributions couldn’t be analyzed. Species that were dependent on natural vegetation for their food, shelter, and nesting sites were less common in corridors and edges than in interiors.
12. Mills, L.S. 1995. Edge effects and isolation: Red-backed voles on forest remnants. Conser. Biol. 9(2):395-403.
Edge effects were examined on the spatial distribution of red-backed voles in forest remnants (unlogged mature-to-old growth forests) surrounded by clearcuts. Voles were found to exhibit a significant negative edge effect with as many as six times the voles per trap in the interior than at the edges while the biomass of coarse woody debris (which has a strong positive association with the voles) showed the opposite trend with numbers increasing from the interior to the edge. While these results may indicate the negative edge effect decreases the functional size of the remnant, the strong degree of isolation of the remnants also plays a role by limiting dispersal into the surrounding matrix.
13. Niemuth, N.D., and M.S. Boyce. 1997. Edge related nest losses in Wisconsin pine barrens. J. Wildl. Manage. 61(4):1234-1239.
Nest predation of artificial nests were examined in regard to edges in pine barren savanna habitat fragments and numbers of corvids (blue jays and American crow) and brown-headed cowbirds were recorded in these areas. The authors found that depredation of nests was higher along the edges than the interior and that the numbers of corvids and cowbirds were higher as well. While predation was higher along the edges, distance from edge was the only significant predictor of nest predation which may be due to the large size of the "small" habitat patches (up to 200 ha).
14. Paton, P.W.C. 1994. The effect of edge on avian nest success: How strong is the evidence? Conser. Biolog. 8(1):17-26.
This paper reviewed, evaluated, and in some cases reanalyzed data from papers that looked at avian nest success and edge effects. The majority of studies found that nest success varied near edges, depredation and parasitism rates increased near edges, there was positive relationship between nest success and patch size, and that edge effects usually occur within 50 m of an edge. In addition to the critique of previous studies the author pointed out the lack of studies that considered natural edges that have existed in the landscape for years.
15. Patton, D.R. 1975. A diversity index for quantifying habitat "edge". Wildl. Soc. Bull. 3(4): 171-173.
The author looked at different proportions of edge for different geometric shapes by applying a diversity or edge index. A circle was found to have the least edge. This diversity index is suppose to provide a way to compare different shapes of openings created by wildlife managers to improve wildlife habitat.
16. Rudnicky T.C., and M.L. Hunter, Jr. 1993. Avian nest predation in clearcuts, forests, and edges in a forest-dominated landscape. J. Wildl. Manage. 57(2):358-364.
The authors used artificial nests to examine predation rates on ground nests in a forested landscape in clearcuts and the adjoining forest as they felt few studies had been conducted in forest dominated landscapes. They found that depredation was higher in the forest than in clearcuts, there was no distance from edge effect and that neither clearcut size nor forest size affected predation rates except in June 1990. Because of the results of their study the authors felt managers should be cautious when extrapolating results from nest predation studies in agricultural landscapes to forest-dominated landscapes.
17. Santos, T., and J.L. Telleria. 1992. Edge effects on nest predation in Mediterranean fragmented forests. Biolog. Conser. 60:1-5.
This paper looked at the effects of fragments on artificial bird nests in an archipelago of small forest tracts surrounded by agricultural land in Central Spain. The study was conducted in the spring of 1988 and yielded the following results: higher predation rates in forest patches than agricultural land and lower predation rates on nests nearer the edge (both opposite to the expected pattern). It was believed that the increased nest predation in these forest tracts could have been caused by the small size of all fragments, with the edge effect influencing the entire forest area (i.e., no genuine forest interior).
18. Sisk, T.D., and C.R. Margules. 1993. Habitat edges and restoration: methods for quantifying edge effects and predicting the result of restoration efforts. Pgs. 57-69 In: D.A. Saunders, R.J. Hobbs, and P.R. Ehrlich (eds.). Nature Conservation 3: The reconstruction of fragmented landscapes. Surrey Beatty and Sons, Australia.
This chapter in the book entitled "Nature Conservation 3: The reconstruction of fragmented landscapes" looked at the effects of habitat edges on the distribution and abundance of animals within heterogeneous landscapes, specifically avian populations and beetle community composition. The avian portion of the paper looked at the differences in response to "hard" and "soft" edges and found that 1/3 of the common species showed no edge response, just over 1/2 of the species at the "hard" edge peaked at the edge or in the intermediate bands, and more species avoided the "soft" edge than the "hard" with a smaller proportion peaking near the edge. In the case of the beetle community, habitat fragmentation was seen to alter their structure and composition within undisturbed habitat near the edge of the remnant.
19. Start, A.N. 1991. How can edge effects be minimized? Pgs. 417-418 In: D.A. Saunders, R.J. Hobbs, and P.R. Ehrlich (eds.). Nature Conservation 2: The role of corridors. Surrey Beatty and Sons, Australia.
This paper was a synopsis to a workshop that looked at the impact of edge effects on a corridor and for the purpose of this paper assumed they were deleterious and that they were a management objective of maintaining maximum diversity within the corridor. The authors reviewed edge effects that might affect corridors, identified factors that contribute to a range of those edge effects and determined actions that could minimize those factors.
20. Wales, B.A. 1972. Vegetation analysis of north and south edges in a mature oak-hickory forest. Ecol. Monog. 42(4):451-471.
This author conducted an analysis of vegetation along both a north and south edge of a mature oak-hickory forest since the edge of a forest is seen to act as an escarpment and the direction of exposure has been found to be paramount in determining the nature of the microclimatic transition. The width of this microclimatic transition zone was narrower on the north boundary where the light regime was dominated by diffuse light, penetration of light was negligible, and the influences of wind and precipitation were most active during the dormant season. The south edge was dominated by a direct light regime which penetrated deep into the southern stand, had a wider microclimatic transition zone and prevailing winds that penetrated into the stand in the growing season.