Analytical Solutions to Trade-Offs between Size of Protected Areas and Land-Use Intensity

Land-use change is affecting Earth's capacity to support both wild species and a growing human population. The question is how best to manage landscapes for both species conservation and economic output. If large areas are protected to conserve species richness, then the unprotected areas must be used more intensively. Likewise, low-intensity use leaves less area protected but may allow wild species to persist in areas that are used for market purposes. This dilemma is present in policy debates on agriculture, housing, and forestry. Our goal was to develop a theoretical model to evaluate which land-use strategy maximizes economic output while maintaining species richness. Our theoretical model extends previous analytical models by allowing land-use intensity on unprotected land to influence species richness in protected areas. We devised general models in which species richness (with modified species-area curves) and economic output (a Cobb-Douglas production function) are a function of land-use intensity and the proportion of land protected. Economic output increased as land-use intensity and extent increased, and species richness responded to increased intensity either negatively or following the intermediate disturbance hypothesis. We solved the model analytically to identify the combination of land-use intensity and protected area that provided the maximum amount of economic output, given a target level of species richness. The land-use strategy that maximized economic output while maintaining species richness depended jointly on the response of species richness to land-use intensity and protection and the effect of land use outside protected areas on species richness within protected areas. Regardless of the land-use strategy, species richness tended to respond to changing land-use intensity and extent in a highly nonlinear fashion.

File: Butsic_etal_2012_ConsBio.pdf

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The ability of zoning and land acquisition to increase property values and maintain largemouth bass growth rates in an amenity rich region

Land use change is a leading cause of environmental degradation in amenity rich rural areas. Numerous policies have been used to combat these negative effects, including zoning and land acquisition. The empirical effects of these policies on the environment and land markets are still debated. Using a coupled economic-ecological model in conjunction with landscape simulations we investigate the effect of zoning and land acquisition on property prices and largemouth bass (Micropterus salmoides) growth in Vilas County, WI, an amenity rich region with growing rural development. Using econometric models of land use change and property prices, we simulate four alternative land use scenarios: a baseline simulation, a zoning change simulation, a land acquisition program simulation, and a land acquisition program + zoning simulation. Each scenario is simulated over 82 separate lakes. For each scenario we calculate the length of a 20-year old largemouth bass, property prices, and number of new residences at simulation years 20, 40 and 60. The policies have small effects on largemouth bass size and property prices on most lakes, although the effects are more pronounced on some. We also test if the increased property values due to land acquisitions are greater than the cost of the land acquisition program and find that in our case, land acquisition does not pay for itself. Our methodology provides a means to untangle the complex interactions between policy, land markets, and the environment. Empirically, our results indicate zoning and land acquisition are likely most effective when targeted to particular lakes.

File: Butsic_largemouth.pdf

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Modeling regional-scale habitat of forest birds when land management guidelines are needed but information is limited

Conservation planning at broad spatial scales facilitates coherence between local land management and objectives set at the state or provincial level. Habitat suitability models are commonly used to identify key areas for conservation planning. The challenge is that habitat suitability models are data hungry, which limits their applicability to species for which detailed information exists, but managers need to address the needs of all at-risk species. We propose a modeling approach useful for regional-scale conservation planning that accommodates limited species knowledge, and identifies what managers should aim for at the local scale. For twenty at-risk bird species, we built models to identify potential habitat using both literature information and empirical data. Species occupancy within potential habitat depends on the presence of intrinsic elements, which we identified for each species so that managers can enhance these elements as appropriate. For most species, the estimated amount of habitat needed to meet population targets was <10% of the mapped potential habitat, with notable exceptions for Northern Goshawk (Accipiter gentilis; 100%), Brown Thrasher (Toxostoma rufum; 63.7%), and Veery (Catharus fuscescens; 17.9%). Model validation showed that interior forest species models performed best. Our modeling framework allowed us to build potential habitat models to various endpoints for different species, depending on the information available, and revealed a number of species for which basic natural history data are missing. Our potential habitat models provide regional perspective and guide local habitat management, and assist in identifying research priorities.

File: Beaudry-et-al-BioCons-2010_0.pdf

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Lakeshore zoning has heterogeneous ecological effects: an application of a coupled economic-ecological model

Housing growth has been widely shown to be negatively correlated with wildlife populations, avian richness, anadromous fish, and exotic invasion. Zoning is the most frequently used public policy to manage housing development and is often motivated by a desire to protect the environment. Zoning is also pervasive, taking place in all 50 states. One relevant question that has received little research concerns the effectiveness of zoning to meet ecological goals. In this paper, we examined whether minimum frontage zoning policies have made a positive impact on the lakes they were aimed to protect in Vilas County, Wisconsin, USA. We used an economic model that estimated when a given lot will be subdivided and how many new lots will be created as a function of zoning. Using the economic model, we simulated the effects of multiple zoning scenarios on lakeshore development. The simulated development patterns were then input to ecological models that predicted the amount of coarse woody debris (CWD) and the growth rate of bluegills as a function of residential density. Comparison of the ecological outcomes under different simulated zoning scenarios quantified the effect of zoning policies on residential density, CWD, and bluegill growth rates. Our results showed that zoning significantly affected residential density, CWD counts, and bluegill growth rates across our study area, although the effect was less clear at the scale of individual lake. Our results suggest that homogeneous zoning (i.e., for a county) is likely to have mixed results when applied to a heterogeneous landscape. Further, our results suggest that zoning regimes with a higher minimum shoreline frontage are likely to have larger ecological effects when applied to lakes that are less developed.

File: Butsic_etal_2010.pdf

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European Bison habitat in the Carpathian Mountains

European Bison (Bison bonasus) barely escaped extinction in the early 20th century and now only occur in small isolated herds scattered across Central and Eastern Europe. The species' survival in the wild depends on identifying suitable habitat for establishing bison metapopulations via reintroductions of new herds. We assessed European Bison habitat across the Carpathian Mountains, a stronghold of European Bison and one of the only places where a viable bison metapopulation may be possible. We used maximum entropy models to analyze herd range maps and habitat use data from radio-collared bison to identify key habitat variables and map European Bison habitat across the entire Carpathian ecoregion (210,000 km2). Forest cover (primarily core and perforated forests) and variables linked to human disturbance best predict bison habitat suitability. Bison show no clear preference for particular forest types but prefer managed grasslands over fallow and abandoned fields. Several large, suitable, but currently unoccupied habitat patches exist, particularly in the eastern Carpathians. This available suitable habitat suggests that European Bison have an opportunity to establish a viable Carpathian metapopulation, especially if recent trends of declining human pressure and reforestation of abandoned farmland continue. Our results also confirm the suitability of a proposed romanian reintroduction site. Establishing the first European Bison metapopulation would be a milestone in efforts to conserve this species in the wild and demonstrate a significant and hopeful step towards conserving large grazers and their ecological roles in human-dominated landscapes across the globe.

File: Kuemmerle_etal_BioCon_2010.pdf

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Wildlife survival beyond park boundaries: the impact of slash-and-burn agriculture and hunting on mammals in Tambopata, Peru.

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.

File: Naughton_etal_ConsBio2003.pdf

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Rural and Suburban Sprawl in the U.S. Midwest from 1940 to 2000 and Its Relation to Forest Fragmentation

Housing growth and its environmental effects pose major conservation challenges. We sought to (1) quantify spatial and temporal patterns of housing growth across the U.S. Midwest from 1940-2000, (2) identify ecoregions strongly affected by housing growth, (3) assess the extent to which forests occur near housing, and (4) relate housing to forest fragmentation. We used data from the 2000 U.S. Census to derive fine-scale backcasts of decadal housing density. Housing data were integrated with a 30-m resolution U.S. Geological Survey land cover classification. The number of housing units in the Midwest grew by 146% between 1940 and 2000. Spatially, housing growth was particularly strong at the fringe of metropolitan areas (suburban sprawl) and in nonmetropolitan areas (rural sprawl) that are rich in natural amenities such as lakes and forests. The medium-density housing (4-32 housing units/km2) category increased most in area. Temporally, suburban housing growth was especially high in the post-World War II decades. Rural sprawl was highest in the 1970s and 1990s. The majority of midwestern forests either contained or were near housing. Only 14.8% of the region's forests were in partial block groups with no housing. Housing density was negatively correlated with the amount of interior forest. The widespread and pervasive nature of sprawl shown by our data is cause for conservation concern. Suburban sprawl has major environmental impacts on comparatively small areas because of the high number of housing units involved. In contrast, rural sprawl affects larger areas but with less intensity because associated housing densities are lower. The environmental effects per house, however, are likely higher in the case of rural sprawl because it occurs in less-altered areas. Conservation efforts will need to address both types of sprawl to be successful.

File: Radeloff_etal_ConsBio2005.pdf

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Spatial patterns of cone serotiny in Pinus banksiana in relation to fire disturbance

Fire disturbance effects on tree species distribution and landscape pattern have been widely studied. However, the effects of differences among fire regimes on the spatial pattern of genetic variability within a tree species have received less attention. The objectives of this study were to examine (a) whether the marked gradient in serotiny in Pinus banksiana along its southern range limit is related to differences in fire regimes and (b) at what scale serotiny varies most strongly in P. banksiana in the US Midwest. P. banksiana in the 450,000 ha Pine Barrens area in northwestern Wisconsin, USA showed a marked broad scale pattern in serotiny. The percentage of serotinous trees was highest in the northeast (mean 83%, S.D. 13.5) and lowest in the southwest (mean 9%, S.D. 3.7). Historic fire regimes were inferred from pre-European settlement (mid-1800s) vegetation data. Serotiny was highest in pine forests that exhibited stand-replacing fires, and lowest in savannas where more frequent but less intense ground fires occurred. The data presented in this study suggest possible spatial control of genetic variability within a tree species by an ecological process (disturbance) at the landscape-scale.

File: Radeloff_etal_FEM2004.pdf

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Modeling forest harvesting effects on landscape pattern in the Northwest Wisconsin Pine Barrens

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.

File: Radeloff_etal_FEM_2006.pdf

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Modeling the influence of dynamic zoning of forest harvesting on a Northern Wisconsin Landscape

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.

File: Zollner_etal_EM_2005.pdf

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