Conservation

Finding a balance between strict protection and multiple use requires data on wildlife survival in human-managed ecosystems. We examined the habitat use and species composition of mammals = 2 kg in size inhabiting an agroforest ecosystem neighboring a park in the Peruvian Amazon. First, we recorded wildlife presence in fields, fallows, and forests within one settlement over a 9-month period. Then we monitored wildlife presence over 21 months in 42 fields across a 65-km transect, including remote and highly disturbed sites. We tested for correlations between the size and number of mammal species visiting fields and human activities measured at different scales. Hunting intensity more powerfully predicted the average biomass and species diversity observed in fields than did vegetation disturbance. The number of commercial hunters in the surrounding community had a stronger impact than did the individual field owner's hunting intensity. Large-bodied species appeared only in remote farms neighboring uninhabited areas in the reserve, indicating that undisturbed forests act as sources for wildlife dispersing into agricultural regions. Farmers in these remote areas experience greater crop and livestock losses to wildlife, but by hunting large game they are able to offset losses with bushmeat gains. In more disturbed areas, crop losses exceeded bushmeat gains, although both occurred at negligible levels. Our case study suggests that large herbivores, large carnivores, and most primates are unlikely to persist in multiple-use zones in Amazonian forests unless hunting is effectively restricted. Even highly disturbed agroforests are not empty of wildlife, however, but are inhabited by a suite of adaptable, fast-reproducing species able to withstand human activity (e.g., brown agoutis [ Dasyprocta variegata ], armadillos [ Dasypus novemcinetus ], and red brocket deer [ Mazama gauazoubira ]). These weedy species may not be of immediate concern to conservation biologists, and they will not attract tourists. But they have both economic and ecological value and deserve to be taken into account in management decisions.

Forest management shapes landscape patterns, and these patterns often differ significantly from those typical for natural disturbance regimes. This may affect wildlife habitat and other aspects of ecosystem function. Our objective was to examine the effects of different forest management decisions on landscape pattern in a fire adapted ecosystem. We used a factorial design experiment in LANDIS (a forest landscape simulation model) to test the effects of: (a) cut unit size, (b) minimum harvest age and (c) target species for management. Our study area was the Pine Barrens of northwestWisconsin, an area where fire suppression has caused a lack of large open areas important for wildlife. Our results show that all three management choices under investigation (cut unit size, minimum harvest age and target species for management) have strong effects on forest composition and landscape patterns. Cut unit size is the most important factor influencing landscape pattern, followed by target species for management (either jack pine or red pine) and then minimum harvest age. Open areas are more abundant, and their average size is larger, when cut units are larger, target species is jack pine, and minimum harvest age is lower. Such information can assist forest managers to relate stand level management decision to landscape patterns.

Dynamic zoning (systematic alteration in the spatial and temporal allocation of even-aged forest management practices) has been proposed as a means to change the spatial pattern of timber harvest across a landscape to maximize forest interior habitat while holding timber harvest levels constant. Simulation studies have established that dynamic zoning strategies produce larger tracts of interior, closed canopy forest, thus increasing the value of these landscapes for interior-dependent wildlife. We used the simulation model LANDIS to examine how the implementation of a dynamic zoning strategy would change trajectories of ecological succession in the Great Divide Ranger District of the Chequamegon-Nicolet National Forest in northern Wisconsin over 500 years. The components of dynamic zoning strategies (number of zones in a scenario and the length of the hiatus between successive entries into zones) and their interaction had highly significant impacts on patterns of forest succession. Dynamic zoning scenarios with more zones and shorter hiatus lengths increased the average amount of the forest dominated by early successional aspen (Populus sp.). Dynamic zoning scenarios with two zones produced more late successional mature northern hardwoods than scenarios with four zones. Dynamic zoning scenarios with very short (30 years) or very long (120 years) hiatus lengths resulted in more late successional mature northern hardwoods than scenarios with intermediate hiatus lengths (60 and 90 years). However, none of the dynamic scenarios produced as much late successional mature northern hardwoods as the static alternative. Furthermore, the amounts of all habitat types in all dynamic zoning scenarios fluctuated greatly in time and space relative to static alternatives, which could negatively impact wildlife species that require a stable amount of habitat above some minimum critical threshold. Indeed, implementing dynamic zoning scenarios of different designs would have both positive and negative effects on wildlife species and for other objectives of forest management.

The lack of long-term baseline data restricts the ability to measure changes in biological diversity directly and to determine its cause. This hampers conservation efforts and limits testing of basic tenets of ecology and conservation biology. We used a historical baseline survey to track shifts in the abundance and distribution of 296 native understory species across 82 sites over 55 years in the fragmented forests of southern Wisconsin. We resurveyed stands first surveyed in the early 1950s to evaluate the influence of patch size and surrounding land cover on shifts in native plant richness and heterogeneity and to evaluate changes in the relative importance of local site conditions versus the surrounding landscape context as drivers of community composition and structure. Larger forests and those with more surrounding forest cover lost fewer species, were more likely to recruit new species, and had lower rates of homogenization than smaller forests in more fragmented landscapes. Nearby urbanization further reduced both alpha and beta understory diversity. Similarly, understory composition depended strongly on local site conditions in the original survey but only weakly reflected the surrounding landscape composition. By 2005, however, the relative importance of these factors had reversed such that the surrounding landscape structure is now a much better predictor of understory composition than are local site conditions. Collectively, these results strongly support the idea that larger intact habitat patches and landscapes better sustain native species diversity and demonstrate that humans play an increasingly important role in driving patterns of native species diversity and community composition.

Incorporating an ecosystem management perspective into forest planning requires consideration of the impacts of timber management on a suite of landscape characteristics at broad spatial and long temporal scales. We used the LANDIS forest landscape simulation model to predict forest composition and landscape pattern under seven alternative forest management plans drafted for the Chequamegon-Nicolet National Forest in Wisconsin. We analyzed 20 response variables representing changes in landscape characteristics that relate to eight timber and wildlife management objectives. AMANOVA showed significant variation in the response variables among the alternative management plans. For most (16 out of 20) response variables, plans ranked either directly or inversely to the extent of even-aged management. The amount of hemlock on the landscape had a surprising positive relationship with even-aged management because hemlock is never cut, even in a clear cut. Our results also show that multiple management objectives can create conflicts related to the amount and arrangement of management activities. For example, American marten and ruffed grouse habitat are maintained by mutually exclusive activities. Our approach demonstrates a way to evaluate alternative management plans and assess if they are likely to meet their stated, multiple objectives. 2008 by Elsevier B.V.

Participation by the public in the management process of public forested lands has led to innovation in the visual simulation of management options. So far, visualization technology has largely been used by researchers and consultants, not by natural resource managers themselves. A three-dimensional forest visualization system, developed for use by the Wisconsin Department of Natural Resources, incorporates a library of photographs of trees, snags, and even logging debris in an effort to depict forest management activities realistically. Managers need only limited training to quickly generate visualizations depicting a specific stand or an entire landscape in its current and potential future states under a variety of silvicultural treatments. We describe the components of the system so that it can be recreated for other regions.