Ecological mechanisms linking protected areas to surrounding lands

Ecology Department, Montana State University, Bozeman, Montana 59717-3460, USA.
Ecological Applications (Impact Factor: 4.09). 07/2007; 17(4):974-88. DOI: 10.1890/05-1098
Source: PubMed


Land use is expanding and intensifying in the unprotected lands surrounding many of the world's protected areas. The influence of this land use change on ecological processes is poorly understood. The goal of this paper is to draw on ecological theory to provide a synthetic framework for understanding how land use change around protected areas may alter ecological processes and biodiversity within protected areas and to provide a basis for identifying scientifically based management alternatives. We first present a conceptual model of protected areas embedded within larger ecosystems that often include surrounding human land use. Drawing on case studies in this Invited Feature, we then explore a comprehensive set of ecological mechanisms by which land use on surrounding lands may influence ecological processes and biodiversity within reserves. These mechanisms involve changes in ecosystem size, with implications for minimum dynamic area, species-area effect, and trophic structure; altered flows of materials and disturbances into and out of reserves; effects on crucial habitats for seasonal and migration movements and population source/sink dynamics; and exposure to humans through hunting, poaching, exotics species, and disease. These ecological mechanisms provide a basis for assessing the vulnerability of protected areas to land use. They also suggest criteria for designing regional management to sustain protected areas in the context of surrounding human land use. These design criteria include maximizing the area of functional habitats, identifying and maintaining ecological process zones, maintaining key migration and source habitats, and managing human proximity and edge effects.

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Available from: Ruth S. Defries, Oct 24, 2014
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    • "In the case of El Yunque National Forest, the largest protected area in Puerto Rico, better interagency collaboration in planning and enforcement of conservation regulations in the surrounding lands would improve conservation of biodiversity and ecosystem services both within and outside the national forest. Studies show that promoting forested coverage beyond the administrative boundary of a protected area increases the effective size of the area conserved and its capacity to conserve viable populations, species richness, and ecosystem services (DeFries et al. 2005, Hansen and DeFries 2007, Hull et al. 2011, Zaccarelli et al. 2008). Finally, government programs that support biodiversity conservation on private lands, such as the US Forest Service Forest Stewardship Program (USDA-FS 2014) and the US Fish and Wildlife Service Partners for Wildlife (USFWS 2014) which assist and incentivize private landowners to manage part of their land for conservation, should be supported and promoted. "

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    • "Less compact PAs (i.e. shapes that depart from circularity) increase representation because, for a given area, they sample more environmental variation (the linear distance between the two closest points within a geometric shape is always larger for less compact ones (Yamaura et al., 2008); however, they negatively influence species survival by increasing the edge-to-area ratios, known to increase the extent of the area exposed to anthropogenic pressures (known as edge effects;Kunin, 1997;Hansen & DeFries, 2007). In the long term, this will reduce the level of biodiversity represented within the boundaries of a PA, and therefore, PAs are generally recommended to have compact shapes (Kunin, 1997). "
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    ABSTRACT: Aim: To assess the relative effects of the spatial features of protected areas (PAs), and their interactions, on species richness representation. Location: Continental America and associated islands. Methods: We used a novel dataset comprising species richness estimates for amphibians, birds and mammals for more than 400 PAs in the Western Hemisphere. Using spatial tools and remote sensing imagery, we calculated four spatial features for each PA: size, shape index, fragmentation level and proximity to the closest PA. The relative effect size of both PA spatial features and environmental covariates on levels of species richness, and how they interact, were assessed using generalized mixed effect models. Results: Spatial features and environmental covariates explained about 61% of the variation in species richness within PAs, with the magnitude of the effect remaining similar among spatial features and taxonomic groups. While area had a positive effect on species richness, shape index and fragmentation had negative effects. Proximity had a significant positive effect only for mammals and a negative effect for all the taxa combined. PA spatial features showed significant interactions between them and with environmental covariates. Main conclusions: We provide the first empirical evidence for the combined and interactive effects of terrestrial PA spatial features on predicting species richness. Our results suggest that the spatial features of PAs have an important effect on species richness and while the magnitude of this effect varies across taxonomic groups, its direction is consistent. Additionally, we show that the effect of one spatial design feature can be amplified or attenuated by that of another. These findings contribute towards a better understanding of the effect of spatial features on the performance of PAs and therefore how best to enhance the spatial configuration of existing and future PAs.
    No preview · Article · Dec 2015 · Diversity and Distributions
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    • "Whilst the goals of on-farm conservation programmes are diverse, including preservation of genetic diversity of crop varieties (Maxted et al., 2002), a major focus of these programmes is conserving native flora and fauna (Joppa et al., 2008). Factors that make on-farm programmes particularly attractive for conservation include: shrinking conservation budgets, the high management costs of protected areas, rising land acquisition costs (James et al., 1999), the need to minimize disturbances to protected areas from adjacent land uses (Hansen and DeFries, 2007), and the higher cost of managing small conservation areas relative to larger ones (Bruner et al., 2004). Moreover, much biodiversity, and many "
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    ABSTRACT: On-farm conservation programs require land managers to pursue both market and non-market objectives (outcomes). If one can identify objectives that are complementary (co-benefits) and competitive (trade-offs) so that co-benefits can be pursued and trade-offs avoided, one may be able to lower the costs to land managers of on-farm conservation programs. We used data from farms in northern Australia to identify potential trade-offs and co-benefits between market and non-market objectives. We used Data Envelopment Analysis (DEA) to assess the relationship between farm ‘inputs’ (e.g. land, labour, capital) and both market and non-market outcomes (e.g. value of on-farm production, turtle biodiversity). The DEA analysis generated an ‘efficiency score’ for each farm; the best scores were associated with properties that used fewest inputs and had the ‘best’ outcome(s). We then looked for statistically significant relationships between those scores and other variables known to influence outcomes. After controlling for biophysical factors (e.g. rainfall, soil type, presence/absence of water), we found little evidence of trade-offs between market and non-market outcomes. We found that farms with many weeds had poor market efficiency scores, suggesting that weed-reduction programs could generate substantive co-benefits for agriculture and biodiversity. Properties managed by people who preferred a small steady income (over a large uncertain income) had higher non-market efficiency scores, suggesting a link between conservation and attitudes to risk. Our results also suggest that encouraging on-farm agricultural diversification, the adoption of environmentally focused land-management plans, and a generally more positive attitude towards conservation could improve environmental outcomes without compromising market outcomes.
    Full-text · Article · Jul 2015 · Biological Conservation
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