FOR-76

Landscape and Management Thomas G. Barnes, Extension Wildlife Specialist

his publication introduces the concepts and Principles of Ecology Tprinciples of landscape ecology for managing To understand landscape ecology, we have to wildlife and other natural resources. It is intended focus on some of its important principles: - to raise public awareness and give an overview of scape composition, structure, function, and a new philosophy and method for managing natu- change. ral resources at the landscape level. • Composition involves the genetic makeup of A landscape is a heterogenous area composed , identity and of of a cluster of interacting ecosystems that are re- in the , and the different types of peated in various sizes, shapes, and spatial rela- communities present. tionships throughout the landscape. • Structure involves the variety of patches have different land forms, types, and or ecosystems and their patterns—the size and land uses. Another way of looking at a landscape arrangement of patches, stands, or ecosystems— is as a mosaic of habitat patches across which or- including the sequence of pools in a stream, ganisms move, settle, reproduce, and eventually snags and downed logs in a , and vertical die and return to the . The best way to envi- layering of vegetation. sion a landscape is to look at the land from an • Function involves climatic, geological, hydro- aerial perspective or to examine aerial photographs logical, ecological, and evolutionary processes to see how a particular piece of land fits into the such as seed dispersion or gene flow. larger picture. • Change involves the continual state of flux Landscape ecology is the study of structure, present in ecosystems. function, and change in a heterogenous land area Figure 1. Landscapes composed of interacting ecosystems. It is an in- A landscape consists of three main compo- consist of the matrix terdisciplinary science dealing with the interrela- nents: a matrix, patches, and corridors (Figure 1). (the dominant feature), tionship between human society and our living If we understand these components and their in- patches, and corridors that space. Landscape ecology is a relatively new sci- terrelationships, we can make better management connect the patches. ence, although Europeans decisions at the landscape level. have been using its prin- Matrix ciples much longer than Patch B Americans. We can learn Matrix corridor a great deal from examin- The matrix, the dominant component in the Patch A ing how the Europeans landscape, is the most extensive and connected have taken an almost landscape type, and it plays the dominant role in completely human-domi- landscape functioning. If we try to manage a habi- corridor nated landscape and at- tat without considering the matrix, we will likely tempted to restore fail to provide what wildlife need in that area. Patch C ecological functions to its For instance, if your goal is to enhance the systems. number of different species in a 40-acre forest patch surrounded by soybean fields, you will not create wildlife openings in the forest. That is, you will not want to create more edge (the outer zone of a patch that differs from its interior) because in an agricultural matrix, any type of opening will This publication is intended to be a companion to FOR-75, “An Ecosystems Approach create more and smaller forested patches in that to Natural Resources Management.” area, further reducing the amount of interior habi- It is well documented that adjacent tat available to the wildlife that need it. affect each other through changes in microcli- The characteristics of matrix structure are the mates and the transfer of nutrients, materials, or density of the patches (porosity), boundary shape, seeds, etc. between communities. These changes networks, and heterogeneity. If an area has been ultimately affect ecological processes such as gene broken up but the patches are fairly close together, flow and species composition in each . the patches are still dense enough to be useful for For example, breaking up the forest or creating animal movement. However, if you open up a large openings in the forest matrix creates smaller for- forested area by creating small openings, the est patches, with the matrix becoming open land patches may not be dense enough to sustain cer- (Figure 3). Thus, fragmentation of forest patches tain kinds of animals, and you could have a prob- results in drier microclimates, which: lem with on other wildlife by raccoons, • alter species composition and favor exotic, in- opossums, black rat snakes, or blue jays. A reduc- vasive species tion in density might also increase nest • increase the susceptibility of windthrow of ex- by brown-headed cowbirds on neotropical migrant isting trees songbirds. We can illustrate how lack of density • exacerbate a loss of forest interior wildlife spe- can create problems with brown-headed cowbirds. cies (like neotropical migrant songbirds) Some parts of eastern Kentucky do not have a large • reduce the genetic diversity of the remaining problem with brown-headed cowbirds because the populations, and matrix there is forested land. However, these birds • allow for the invasion of exotic, weedy species. pose a potential problem in other areas of eastern Ultimately, small preserves that are set aside Kentucky where the matrix has been highly frag- for their content may fail unless people intervene mented by coal mining, , and urban de- with intensive management, which is expensive velopment (Figure 2). and time consuming. To refer again to the example Boundary shape also has implications for of the glade, opening the surrounding forest habi- neotropical migrant birds and edge species of wild- tat increases the kinds and numbers of exotic plant life. The more uneven the boundary, the more species that overcome the rare plants unless in- edge. Within matrix areas, networks connect habi- tensive, site-specific management like herbicide tats of different size and shape, creating what is treatment, hand pulling, etc. is implemented. called heterogeneity within the landscape. These Similarly, fragmenting the forest surrounding a different habitat patches usually are replicated cave could alter the cave’s microclimate; certainly, throughout the matrix. nonpoint source would alter its climate For example, the of eastern Kentucky vary and make the cave unsuitable for bats or other by slope, landscape position, and soil type. Ridgetop unique organisms like blind cavefish. forests are dominated by pine and oaks, cove sites are mixed hardwood stands, south- and west-fac- ing slopes are oak-hickory forest, etc. If a chance Patches event like a tornado were to occur, it might tear up Patches are nonlinear surface areas that differ one or two areas, but it would not wipe out all habi- in vegetation and landscape from their surround- tat for a species because the same habitat type is ings. They are units of land or habitat that are replicated several times in an area. The overall dam- heterogeneous when compared to the whole. They age to wildlife would not be as great because that include four different types: , remnant, type of habitat would still be close by. environmental , and introduced. • Disturbance patches are either natural or artifi- Context vs. Content cial. They result from various activities, includ- When natural resources are managed at the land- ing agriculture, , , and scape level, context—where the biological element weather (i.e., tornados, hurricanes, ice storms, is placed in the landscape—is just as important as etc.). If left alone, a disturbance patch will even- content. In other words, you must consider the sur- tually change until it combines with the matrix. rounding matrix when attempting to conserve an • Remnant patches result when humans alter the area for its unique ecological attributes. Thus, if the landscape in an area and then leave parcels of land is being set aside to preserve rare plants (such the old habitat behind. Remnant patches are as wildflowers in a glade) or animals (such as bats generally more ecologically stable and persist in a cave), the content—or community—we are longer than disturbance patches. interested in is affected by the context of the envi- • Environmental resource patches occur because ronment if the surrounding landscape is altered. of an environmental condition such as a wet- land or cliff line.

2 Figure 2. Eastern Kentucky forest matrix has been fragmented by Figure 3. Notice how the forested matrix has begun to be converted to an mining, agriculture, and human habitation. “open lands” matrix.

• Introduced patches are ones in which people est. Thus, from a habitat standpoint, the first im- have brought in nonnative plants or animals or portant concept is patch size, which determines rearranged native species. Animals moving from how much energy can be stored in that patch as one area to another can also bring in these well as the number of species that can reside there. nonnative elements. A larger patch can normally support a larger num- ber of species and a greater variety of habitat types (Figure 4). Patches as Islands Several aspects of patches are important from an ecological perspective and affect landscape-level Worse Better management decisions. The approach used most

often in analyzing patch habitats is to think of them Better as islands. Much of the current thinking about land- Size scape patch management has its roots in the theory of island . This theory was developed in 1967 by MacArthur and Wilson to explain the patterns of on oceanic islands. It Shape has also proven useful and applicable to a variety of ecological situations because an island is simply defined as a patch or parcel of favorable habitat surrounded by unfavorable habitat. Just as wildlife Configuration disperse to oceanic islands, terrestrial wildlife and plants move between habitat islands. MacArthur and Wilson’s theory suggests that various dispersal events could therefore be predicted. A key concept in MacArthur and Wilson’s Number theory is that an equilibrium point exists in a popu- Worse lation between the rate that new species come in and the rate that previously existing species become Figure 4. The size, shape, configuration, and number extinct. Once this point is reached, the island’s of patches all affect the populations of species are then maintained at this Patch Size and Edge Effect amount of interior habitat equilibrium diversity. Island populations, then, have A concept getting closer consideration these in the patch. Small, single, a tendency to “seek out” this equilibrium. days is the relationship between habitat patch size rectangular patches provide Island size and relative isolation (distance to and the edge effect. In 1933, in Game Management, the last amount of interior the mainland) affect both these rates and their Aldo Leopold wrote that creating edge and maxi- habitat, and large circular equilibrium point. Relatively isolated and small patches provide the most mizing the amount of interspersion, or the juxta- interior habitat. fragments offer the lowest equilibrium species di- position, of habitats was beneficial for wildlife. Held versity, while nearby large islands offer the high- as dogma by wildlife biologists until recently, this philosophy is unfortunately the most overused con-

3 cept Leopold discussed. He stated that increasing migrants, the minimum patch size should be the edge increases the number of wildlife species in 10,000 acres. an area. However, if we look at things from a land- Patch shape is also important. A circular patch scape perspective, edge is the one habitat not in minimizes the amount of edge compared to a thin, short supply. Although edge is good for certain spe- rectangular strip patch, which has only a narrow cies, particularly generalist or game species, it fa- band of interior habitat. If the strip is narrow vors those species over interior species, or species enough, there is no interior habitat for interior that require specific habitat types. species, and ultimately the diversity in the strip Unfortunately, fragmented habitats with a large would be low. percentage of edge can become an . There are also functional ramifications related These islands of habitat may look good for some to edges and patch size. In general, the higher the species of birds to build their nests in, but they interior-to-edge ratio, the less patch border you also attract a wide host of nest predators, includ- have, which decreases the amount of interaction ing raccoons, skunks, opossums, blue jays, and rat with the surrounding matrix. A higher interior- snakes. These animals decrease the nesting suc- to-edge ratio also: cess of any birds in that area. For instance, in a • decreases the probability of barriers that could recent study, scientists compared nesting success limit the movement of organisms of loggerhead shrikes in fencerow habitat versus • decreases the probability of habitat diversity those in more contiguous forested habitat. In within the patch, which would not necessarily fencerow habitats, the bird’s nesting success be harmful because it would be natural, not dropped almost to the point that they could not artificial, diversity replace themselves due to nest predation. • decreases the importance of corridors for spe- Additionally, patch size has implications for cies movement, as they are able to move more neotropical migrant songbirds if the surrounding freely throughout the matrix matrix is good habitat for brown-headed cowbirds. • increases species diversity and the total number If present in the matrix (and they will be present of animals within the patch. in an agricultural matrix), cowbirds will lay their A low interior-to-edge ratio would do exactly eggs in the nests of neotropical migrant birds. The the opposite. neotropicals cannot recognize the cowbirds’ eggs, and they end up raising cowbirds rather than their own species. It is important to keep patches in the landscape One of the issues related to patch size is habi- as large as possible because the habitat in shortest tat fragmentation. Fragmentation is a process that supply in the landscape is contiguous forest or occurs along a continuum (Figure 5) in which a . An important consideration from a particular area is initially all one habitat type (a landscape perspective is how to maximize patch forest, for example) and is eventually decreased size and minimize the edge effect because nest until only isolated patches remain. It results in parasitism begins to drop off significantly at 50 habitat loss and discontinuity and eventually leads yards from a forest edge. Therefore, anything more to habitat isolation. Fragmentation ranges from than 50 yards into a patch could be considered creation of small disturbance patches to wide- interior habitat. spread habitat loss and insularization. So, in a patch 100 yards across, how much would There are two components to fragmentation: 1) be interior habitat? None would be interior habitat a decrease in the amount of interior habitat and 2) because if you go 50 yards in on each side, there is a decrease in the connectivity between those habi- nothing left. In general, as patches get larger, there tat patches. As an example, suppose we started out is more interior habitat. And if a patch is large with all forestland; then, three farmers move in and enough, there is significantly more interior habi- farm their small areas. As time passes, development tat. But how big should habitat patches be to mini- creeps in, and the farms expand their agricultural mize the influence of exotic or edge species? This base, resulting in larger gaps between habitat requirement varies by species; nest parasitism by patches. At this point, the landscape is moving from cowbirds, for example, may extend up to 900 yards a forest matrix to an agricultural matrix. In the be- into the forest interior. There are no definitive ginning, there is still connectivity between forest guidelines except “the bigger, the better.” patches even though it is narrow. At the endpoint Furthermore, patch shape and configuration of the continuum, there is a totally different type also influence how large the patches need to be. of habitat. From the wildlife standpoint, many of Scientists estimate that if we are to maintain mini- the original species would have two options: move mum viable populations for many neotropical to another area, or perish.

4 At the present time, forested wildlife habitat in the landscape often occurs in patches within a an agricultural landscape matrix. Managing wild- Forest Matrix Agricultural Matrix life at the landscape level is an attempt to unite habitat patches (through the use of corridors, spe- c cifically riparian forests or fencerow habitats) to allow native to flourish across the gap formation fragmentation complete range of environmental gradients or be- tween ecosystems. Viewed in another context, we b do not necessarily have to connect habitat frag- ments, but rather direct our management to al- Figure 5. Fragmentation low for the natural dispersal of wildlife. begins with small gap Species can move across land more easily than formation in the matrix. Over time, the gaps may across water. However, fragmentation in terrestrial get larger, resulting in a systems creates something similar enough to the shift in the matrix. island effect that predictions can be made based on island biogeographic principles. How easily organ- of premeditated and accidental introduction of isms can move across the landscape is determined exotic plants and animals are well documented. by the density of the landscape. Thus, a high den- These alien species, particularly those intro- sity of patches would tend to be similar to a large duced by humans into environments they would number of stepping-stones that organisms could use not have reached through normal dispersal meth- as cover as they go from one patch to another. ods, have transformed, and are continuing to trans- As noted earlier, the number of species that re- form, entire ecosystems. For example, the side in a patch increases as the size of a patch in- American chestnut once accounted for one-quar- creases. However, patches are not a random sample ter of the standing timber volume in the eastern or a subset of the landscape. As a general rule, when deciduous forest. Today this species is reduced to you fragment the habitat, you section off one par- sprouts and a few adults that were not destroyed ticular type of habitat (Figure 6). Thus, if you are by the introduced chestnut blight. This invasion going to fragment a habitat patch, you need to look by an alien species has dramatically altered the at the habitat types within both the patch and the composition, structure, and functioning of this matrix and attempt to maintain each patch type. ecosystem. Habitat fragmentation can be viewed as ei- ther a positive or negative feature in the land- Figure 6. How scape. It can have positive effects by increasing fragmentation occurs is habitat diversity, creating beneficial juxtaposi- important. If you fragment A tion of habitats, and, as Leopold said, increasing along Line 1, over time D edge, which favors generalist wildlife species like or Community A will become extinct. If white-tailed deer, raccoon, opossum, northern you fragment along Line bobwhite quail, etc. 2, Population A does not B Fragmentation can be viewed as negative when: become extinct. • there is a loss of habitat, C • smaller habitat patches are created that lead to local or isolation, B • habitats are no longer connected, particularly if D the fragmentation is caused by a nonforestry A activity such as urbanization, and Line 1 • the amount of edge is increased because frag- Line 2 mented habitat is harmful to interior species like bobolinks, wood thrushes, etc.

C D Fragmentation and Nonnative Species As habitats are fragmented into smaller pieces, B one final negative impact occurs: the invasion of nonnative or exotic organisms. Current estimates indicate that more than 25 percent of the flora in the United States is exotic. The history and folly

5 It has been estimated that exotic animals and corridors are mainly dominated by edge species, plants harm or threaten resources in at least 109 whereas wider strip corridors, which may have national parks. An introduced tree, the Austra- mostly interior species, function for better move- lian tree, has infested more than eight million acres ment of animals. of native sawgrass prairies in Everglades National Corridors can serve as a conduit for movement Park. In addition to causing loss of habitat for or act as a barrier or filter (which may serve as a wading birds and increased drying of the marsh, barrier to gene flow). For example, can serve this pest is particularly intrusive. It does not re- as an almost complete barrier to amphibian move- spond to burning or herbicide treatment and may ment, ultimately isolating individual populations. increase as a consequence of these eradication methods. The Loxahatchee National Wildlife Corridor Structure and Function Refuge is spending at least $75,000 a year in an Corridor structure and function depend on a attempt to control the invading tree. variety of different factors, including degree of In addition to completely altering ecosystem curvilinearity, breaks, narrows, nodes, and connec- structure and composition, exotics cause other tivity. problems. In native ecosystems, a species is kept • Curvilinearity, or the twisting and winding of in check by ecosystem control like the corridor, has functional ramifications re- for food, space, or water; pathogens that cause dis- lated to edge. A higher degree of curvilinearity ease; or predators. When a new species is intro- increases edge. duced into an ecosystem, those same control • Breaks occur where the matrix divides up a mechanisms usually are not present. What usu- continuous corridor. They may not affect move- ally happens is that its population blossoms with- ment for some species, but for others—particu- out any natural controls. Exotics have also been larly plant species—they may stop the flow of known to hybridize with related native species, species, genes, and energy through that system. resulting in a lack of genetic fitness for the native • Narrows, caused when some of the corridors population. Introduced predators may cause a de- narrow down, keep some species from moving in native prey species because the “naive” through the restricted area. native prey have not become adapted throughout • Nodes are corridor intersections, where, ac- time to deal with the new predator. cording to studies from England, numerous may also bring new diseases interior species are sometimes found. into an ecosystem that native species are not • Connectivity of corridors should be main- adapted to combating. Finally, an introduced spe- tained—that is, they should be kept continu- cies may adversely affect the workings of human ous and unbroken. communities by disrupting businesses, hastening the decline of an important food or recreation re- source, or affecting water quality. Corridor Drawbacks Corridors also have some drawbacks. They en- Corridors courage predators to alter their search patterns, re- sulting in increased predation on native wildlife The final landscape component is the corridor, species. Small animals that use a path as a corridor the strip of land that differs from the matrix on for travel will be more susceptible to reduction by either side. Corridors are areas that link patches predation. Consider how the eastern diamond- together, serving as highways or conduits for or- backed rattlesnake likes to lie next to a hiking path ganisms to transfer or move from patch to patch. to get sun. Additionally, think of the humans using Corridors are a unique mixture of environmental that footpath. The humans would probably destroy and biotic attributes from the surrounding matrix every rattlesnake they encountered, ultimately lead- and patches. They have origins and types similar ing to fewer rattlesnakes. to those of patches: there are disturbance, rem- Another drawback is that some corridors, like nant, environmental resource, and planted corri- roads or railroad rights-of-way, can be a conduit dors. There are also stream corridors such as the for the invasion of exotic organisms or diseases path followed by a river or stream and the strips and pathogens. of streamside vegetation so important to migrat- Here is a landscape-level example: If you have ing wildlife. corridors connecting two patches that have nest Different types of corridors foster different spe- predators such as raccoons and opossums, the cies. Corridors function in several ways to pro- predators will move along these corridors in order vide habitat for various species, especially the to have cover. By their movement patterns, they smaller ones like chipmunks. Line or narrow strip are going to increase their predation on birds in

6 that new area. The area can become very hazard- ous for many types of wildlife, particularly turkeys. Current research findings in the southeastern states on turkey predation occurring along ripar- ian habitats indicate that the narrow corridors of suitable habitat allow predators like the raccoon searching for turkey hens and nests to find and eat their prey more easily. The proximate cause of death is predation, but the ultimate problem is a lack of suitable corridor width (habitat) that would make it more difficult for predators to search the appropriate habitat. The message is simple: the wider we make these corridors, the better, because doing so will decrease the chance of predators finding their prey (Figure 7). These wide strips may need to be several miles across for some bigger species like black bear, but only a few yards wide for smaller species. Any time Figure 7. Corridors need a corridor is 100 yards wide, the habitat’s interior to be wide enough to provide more positive characteristics change, and nest predation drops moved by water), and any management technique off significantly thereafter. benefits for wildlife. This that affects wildlife would affect plants that are narrow riparian corridor spread by zoochores (berries). The result of these probably produces more Landscape Change activities could be good or bad, depending on negative impact on wildlife. Landscapes change, even though we tend to whether it is a species that you want to spread. manage land with the idea that it will always be in some static community. But we all recognize Dynamics that ecological communities are dynamic, ever- Finally, one of the aspects of landscape ecol- changing entities. For instance, when a tree falls, ogy that ecologists have only recently explored is it creates a gap in the landscape matrix. This gap metapopulation. A metapopulation is a network will eventually change and once again become part of semi-isolated populations with some level of of the matrix. regular or intermittent migration and gene flow When you create a change, you have to con- among them. In simpler terms, it is a population sider the impact it will cause on the landscape, not of populations. just for the present moment but also for 50 to 100 In metapopulation dynamics, individual popu- years in the future. For example, if you clearcut 10 lations may go extinct, but then they can be re- of 100 acres at five-year intervals, over the next 20 colonized from other populations (Figure 8). If we to 30 years all those clearcuts and the resulting for- drive these individual populations down to low est will end up at the pole stage (small trees that enough numbers and do not get movement be- are the size of poles) at one time. From a biological tween populations, serious genetic problems may diversity standpoint, the pole stage is the least con- develop for maintaining the species. Even a small ducive for promoting biological diversity. There- amount of movement between populations will fore, it is vitally important to project the effects of keep the genetic situation somewhat stable. management prescriptions well into the future. Another force that alters ecosystems is the movement of plants by seeds. For example, Source and Sink Patches anemochores are seeds that are blown with the If there is no movement, those populations will wind, like maple seeds. If we cut a forest down probably go extinct, depending on whether they and create a gap, this change allows the wind to exhibit a source or sink patch of a metapopulation. move through, spreading these seeds over greater Source patches will always stay in a particular lo- distances and affecting forest community structure. cale and contribute individuals to all the other It has been hypothesized that many of the unique patches in the landscape. Sink patches allow popu- forest types in the are being lations or individuals to become extinct because replaced by red maple. Could this be a result of they do not contain conducive habitat for the spe- previous harvesting strategies? Similarly, if you cies to exist. For example, many times with terri- impact the of or riparian sys- torial wildlife species a source patch of habitat or tems, you would affect the hydrochores (seeds population will be full or at .

7 poor. In the winters of 1976 and 1977 in Ken- tucky, very cold weather occurred along with abundant snow and ice. Unfortunately, some of the patches of quail totally lost their populations. Over time, even with poor movement, those sink sink patches have become repopulated, although it has taken 20 years for some local populations to re- source cover. In other cases, significant habitat alteration occurred that prevented quail from repopulating sink some areas, and these populations became extinct. source In these cases, allowed the spe- cies to survive and ultimately recover small popu- sink lations throughout its range. An important point concerning meta- populations has to do with the time scale used in making management decisions. Many times biolo- gists make decisions based on what the popula- sink tion level is at the present time. With sink sink metapopulation dynamics, however, you have to consider and indications of the area’s total potential. As in the case of the quail, it has taken 20 years to restore some local populations, but many have still not recovered and may never Figure 8. A recover due to continued habitat degradation. metapopulation is a population of source and sink populations. Thus, some animals move to the sink patch. Even Appropriate Management though it may not be the best habitat for some Understanding metapopulation dynamics can species, birds, for instance, may be able to nest lead to appropriate management at the landscape and be successful there. level. As we transform large expanses of relatively Another advantage of the sink population is that uniform habitat patches in the landscape matrix, if some catastrophic event occurs in one sink patch physical changes occur that create the island effect resulting in the extinction of its members, another in the resulting fragments. Such changes include: patch could help to repopulate it. Thus, the sink • a decrease in size of the patches patches help to stabilize the population over time. • an increase in the proportion of edge, and What happens in one patch is asynchronous to what • changes in patch microclimate, including in- happens in the rest of the patches. creased sunlight, greater temperature fluctua- Another important attribute about meta- tions, and greater exposure to wind. populations is that in some cases they may actu- ally buffer the species from extinction because of These effects can mean: the relative isolation and protection of the source Educational programs of the • local extinctions of organisms Kentucky Cooperative Extension and sink patches. For example, if a disease in one • reduced dispersal and recolonization of habitat Service serve all people patch wipes out all the individuals there, despite regardless of race, color, age, patches sex, religion, disability, or national the connectivity between the patches, there is no origin. Issued in furtherance of • invasion of exotic or nonnative species way the disease could spread to all the popula- Cooperative Extension work, Acts • increased nest parasitism or predation on birds, of May 8 and June 30, 1914, in tions. Therefore, the concept of metapopulations cooperation with the U.S. and Department of Agriculture, C. plays a very important role in the management of • a reduction in the diversity of forest interior Oran Little, Director of wildlife today. Cooperative Extension Service, wildlife species. University of Kentucky College of An example will serve to illustrate the impor- Agriculture, Lexington, and tance of understanding metapopulations when Kentucky State University, Although metapopulation dynamics and the Frankfort. Copyright © 2000 for managing wildlife at the landscape level. North- materials developed by the concepts of landscape ecology are complex and dif- University of Kentucky ern bobwhite quail exist in a series of ficult for the general public to understand, we must Cooperative Extension Service. metapopulations. Today, they live in fragments of This publication may be make the effort to understand these concepts be- reproduced in portions or its habitats with some movement by animals between entirety for educational or cause of their importance in determining decisions nonprofit purposes only. the fragments. Sometimes that movement is very Permitted users shall give credit about landscape-level and wildlife management. to the author(s) and include this copyright notice. Publications are also available on the World Wide Web at: http://www.ca.uky.edu. Issued 9-2000. 8