Restoration of Fragmented Landscapes for the Conservation of Birds: A General Framework and Specific Recommendations for Urbanizing Landscapes

Humans fragment landscapes to the detriment of wildlife. We review why fragmentation is detrimental to wildlife (especially birds), review the effects of urbanization on birds inhabiting nearby native habitats, suggest how restoration ecologists can minimize these effects, and discuss future research needs. We emphasize the importance of individual fitness to determining community composition. This means that reproduction, survivorship, and dispersal (not simply community composition) must be maintained, restored, and monitored. We suggest that the severity of the effects of fragmentation are determined by (1) the natural disturbance regime, (2) the similarity of the anthropogenic matrix to the natural matrix, and (3) the persistence of the anthropogenic change. As a result, urbanization is likely to produce greater effects of fragmentation than either agriculture or timber harvest. Restoration ecologists, land managers, and urban planners can help maintain native birds in fragmented landscapes by a combination of short‐ and long‐term actions designed to restore ecological function (not just shape and structure) to fragments, including: (1) maintaining native vegetation, deadwood, and other nesting structures in the fragment, (2) managing the landscape surrounding the fragment (matrix), not just the fragment, (3) making the matrix more like the native habitat fragments, (4) increasing the foliage height diversity within fragments, (5) designing buffers that reduce penetration of undesirable agents from the matrix, (6) recognizing that human activity is not compatible with interior conditions, (7) actively managing mammal populations in fragments, (8) discouraging open lawn on public and private property, (9) providing statutory recognition of the value of complexes of small wetlands, (10) integrating urban parks into the native habitat system, (11) anticipating urbanization and seeking creative ways to increase native habitat and manage it collectively, (12) reducing the growing effects of urbanization on once remote natural areas, (13) realizing that fragments may be best suited to conserve only a few species, (14) developing monitoring programs that measure fitness, and (15) developing a new educational paradigm.     

The Speed of Range Shifts in Fragmented Landscapes

Species may be driven extinct by climate change, unless their populations are able to shift fast enough to track regions of suitable climate. Shifting will be faster as the proportion of suitable habitat in the landscape increases. However, it is not known how the spatial arrangement of habitat will affect the speed of range advance, especially when habitat is scarce, as is the case for many specialist species. We develop methods for calculating the speed of advance that are appropriate for highly fragmented, stochastic systems. We reveal that spatial aggregation of habitat tends to reduce the speed of advance throughout a wide range of species parameters: different dispersal distances and dispersal kernel shapes, and high and low extinction probabilities. In contrast, aggregation increases the steady-state proportion of habitat that is occupied (without climate change). Nonetheless, we find that it is possible to achieve both rapid advance and relatively high patch occupancy when the habitat has a “channeled” pattern, resembling corridors or chains of stepping stones. We adapt techniques from electrical circuit theory to predict the rate of advance efficiently for complex, realistic landscape patterns, whereas the rate cannot be predicted by any simple statistic of aggregation or fragmentation. Conservationists are already advocating corridors and stepping stones as important conservation tools under climate change, but they are vaguely defined and have so far lacked a convincing basis in fundamental population biology. Our work shows how to discriminate properties of a landscape''s spatial pattern that affect the speed of colonization (including, but not limited to, patterns like corridors and chains of stepping stones), and properties that affect a species'' probability of persistence once established. We can therefore point the way to better land use planning approaches, which will provide functional habitat linkages and also maintain local population viability.     

Factors Influencing the Ranging Behavior of Chacma Baboons (Papio hamadryas ursinus) Living in a Human-Modified Habitat

The introduction and eradication of alien invasive plant species potentially alters feeding and spatial ecology of wild primates. We investigated whether the removal of an important dietary resource for wild chacma baboons (Papio hamadryas ursinus), black wattle (Acacia mearnsii), from a nature reserve would result in longer daily path lengths (DPLs) and greater movement toward other resources, specifically alternative black wattle stands outside the reserve, agricultural plots, and sleeping and geophagy sites. We fitted a juvenile male baboon with a self-releasing GPS collar to track the focal troop’s movements on Wildcliff Nature Reserve and adjacent properties, located in the Western Cape, South Africa, from January 25, 2010 to January 18, 2011. During this time, Working for Water, an environmental conservation initiative of the South African Department of Water Affairs, removed black wattle from the baboons’ home range. We estimated monthly home range (5.30–20.58?km²) and DPL (1.7–11.7?km) and quantified the baboons’ use of five dominant vegetation types. Our vegetation use-availability analysis indicated that the troop preferred black wattle, Afromontane forests, and, to a lesser extent, pasture, but used agricultural plots and fynbos less than expected by availability. With increasing black wattle removal in the core area, the troop traveled further toward distant sources of black wattle, using sleeping sites out of their core area to accommodate such long day journeys. A general linear model indicated that movement to black wattle stands, as well as changing sleeping sites, day length, and both spring and winter seasons all significantly increased DPL. We suggest the influence that alien invasive species and their eradication has on ranging behavior should be a consideration in primate conservation and management policies.     

Fenced and Fragmented: Conservation Value of Managed Metapopulations

Population fragmentation is threatening biodiversity worldwide. Species that once roamed vast areas are increasingly being conserved in small, isolated areas. Modern management approaches must adapt to ensure the continued survival and conservation value of these populations. In South Africa, a managed metapopulation approach has been adopted for several large carnivore species, all protected in isolated, relatively small, reserves that are fenced. As far as possible these approaches are based on natural metapopulation structures. In this network, over the past 25 years, African lions (Panthera leo) were reintroduced into 44 fenced reserves with little attention given to maintaining genetic diversity. To examine the situation, we investigated the current genetic provenance and diversity of these lions. We found that overall genetic diversity was similar to that in a large national park, and included a mixture of four different southern African evolutionarily significant units (ESUs). This mixing of ESUs, while not ideal, provides a unique opportunity to study the impact of mixing ESUs over the long term. We propose a strategic managed metapopulation plan to ensure the maintenance of genetic diversity and improve the long-term conservation value of these lions. This managed metapopulation approach could be applied to other species under similar ecological constraints around the globe.     

Influence of Fire Mosaics,Habitat Characteristics and Cattle Disturbance on Mammals in Fire-Prone Savanna Landscapes of the Northern Kimberley

Patch mosaic burning, in which fire is used to produce a mosaic of habitat patches representative of a range of fire histories (‘pyrodiversity’), has been widely advocated to promote greater biodiversity. However, the details of desired fire mosaics for prescribed burning programs are often unspecified. Threatened small to medium-sized mammals (35 g to 5.5 kg) in the fire-prone tropical savannas of Australia appear to be particularly fire-sensitive. Consequently, a clear understanding of which properties of fire mosaics are most instrumental in influencing savanna mammal populations is critical. Here we use mammal capture data, remotely sensed fire information (i.e. time since last fire, fire frequency, frequency of late dry season fires, diversity of post-fire ages in 3 km radius, and spatial extent of recently burnt, intermediate and long unburnt habitat) and structural habitat attributes (including an index of cattle disturbance) to examine which characteristics of fire mosaics most influence mammals in the north-west Kimberley. We used general linear models to examine the relationship between fire mosaic and habitat attributes on total mammal abundance and richness, and the abundance of the most commonly detected species. Strong negative associations of mammal abundance and richness with frequency of late dry season fires, the spatial extent of recently burnt habitat (post-fire age <1 year within 3 km radius) and level of cattle disturbance were observed. Shrub cover was positively related to both mammal abundance and richness, and availability of rock crevices, ground vegetation cover and spatial extent of ≥4 years unburnt habitat were all positively associated with at least some of the mammal species modelled. We found little support for diversity of post-fire age classes in the models. Our results indicate that both a high frequency of intense late dry season fires and extensive, recently burnt vegetation are likely to be detrimental to mammals in the north Kimberley. A managed fire mosaic that reduces large scale and intense fires, including the retention of ≥4 years unburnt patches, will clearly benefit savanna mammals. We also highlighted the importance of fire mosaics that retain sufficient shelter for mammals. Along with fire, it is clear that grazing by introduced herbivores also needs to be reduced so that habitat quality is maintained.     

Diademed Sifaka (Propithecus diadema) Ranging and Habitat Use in Continuous and Fragmented Forest: Higher Density but Lower Viability in Fragments?

The mechanisms through which forest fragmentation threatens the survival of mammal populations remain poorly known, yet knowledge of this process would greatly aid conservation efforts. I investigated ranging behaviors of diademed sifakas ( Propithecus diadema ) in continuous and fragmented forest at Tsinjoarivo, eastern Madagascar, using focal animal observations to examine home range size, daily path length (DPL), and habitat use relative to forest edges over 12 mo. Sifaka groups in forest fragments had home ranges that were 25–50 percent as large as continuous forest groups, and moderately reduced DPLs. Continuous forest groups foraged more than expected near forest edges while fragment groups avoided edges. Fragments have higher population density than continuous forest; however, several lines of evidence suggest that fragment groups' food resources may be denser, but lower quality. Continuous forest groups appear to be energy-maximizers, maintaining large ranges and preferentially feeding in rare fruiting trees found only in continuous forest interiors, while fragment groups appear to be time-minimizers, using small home ranges and primarily feeding on mistletoe (a fallback food in continuous forest). Therefore, the consequences of fragmentation on long-term viability remain unknown; it is possible that the advantage of increased density is outweighed by longer-term demographic challenges, or other threats ( e.g. , nutrition, health, social behavior, disease). When animals stranded in forest fragments exhibit complex and potentially unpredictable responses, simple ecological proxies ( e.g. , incidence patterns and density) are probably inadequate in assessing population health and viability. Ecological study and monitoring is essential in judging the viability of fragmented populations.     

Flying between Sky Islands: The Effect of Naturally Fragmented Habitat on Butterfly Population Structure

High elevation montane areas are called “sky islands” when they occur as a series of high mountains separated by lowland valleys. Different climatic conditions at high elevations makes sky islands a specialized type of habitat, rendering them naturally fragmented compared to more continuous habitat at lower elevations. Species in sky islands face unsuitable climate in the intervening valleys when moving from one montane area to another. The high elevation shola-grassland mosaic in the Western Ghats of southern India form one such sky island complex. The fragmented patches make this area ideal to study the effect of the spatial orientation of suitable habitat patches on population genetic structure of species found in these areas. Past studies have suggested that sky islands tend to have genetically structured populations, possibly due to reduced gene flow between montane areas. To test this hypothesis, we adopted the comparative approach. Using Amplified Fragment Length Polymorphisms, we compared population genetic structures of two closely related, similar sized butterfly species: Heteropsis oculus, a high elevation shola-grassland specialist restricted to the southern Western Ghats, and Mycalesis patnia, found more continuously distributed in lower elevations. In all analyses, as per expectation the sky island specialist H. oculus exhibited a greater degree of population genetic structure than M. patnia, implying a difference in geneflow. This difference in geneflow in turn appears to be due to the natural fragmentation of the sky island complexes. Detailed analysis of a subset of H. oculus samples from one sky island complex (the Anamalais) showed a surprising genetic break. A possible reason for this break could be unsuitable conditions of higher temperature and lower rainfall in the intervening valley region. Thus, sky island species are not only restricted by lack of habitat continuity between montane areas, but also by the nature of the intervening habitat.     

大凉疣螈栖息地现状调查及其保护

大凉疣螈Tylototriton taliangensis为四川省特有物种,国家二级重点保护动物。2009年3月～2010年2月,通过野外调查和对管理部门、当地居民的访问以及市场调查,发现大凉疣螈仅分布在昭觉县、冕宁县、美姑县、峨边县及石棉县等8个县,海拔2000～3500m之间的植被丰茂、环境潮湿的山间凹地静水中,分布区域狭窄。由于人类活动范围的扩大等诸多因素导致湿地减少,种群数量下降。通过信息收集,进行相关分析,提出了对大凉疣螈的有效保护对策。     

Habitat Selection and Movement of Pond-Breeding Amphibians in Experimentally Fragmented Pine Forests

ABSTRACT Population-level responses of amphibians to forest management regimes are partly dictated by individual behavioral responses to habitat alteration. We examined the short-term (i.e., 24-hr) habitat choices and movement patterns of 3 amphibian species—southern leopard frogs (Rana sphenocephala), marbled salamanders (Ambystoma opacum), and southern toads (Bufo terrestris)—released on edges between forest habitats and recent clear-cuts in the Upper Coastal Plain of South Carolina, USA. We predicted that adult frogs and salamanders would preferentially select forest using environmental cues as indicators of habitat suitability. We also predicted that movement patterns would differ in clear-cuts relative to forests, resulting in lower habitat permeability of clear-cuts for some or all of the species. Using fluorescent powder tracking, we determined that marbled salamanders selected habitat at random, southern toads preferred clear-cuts, and southern leopard frogs initially selected clear-cuts but ultimately preferred forests. Frogs exhibited long-distance, directional movement with few turns. In contrast, toads exhibited wandering behavior and salamanders moved relatively short distances before locating cover. Southern toads and southern leopard frogs moved farther in forests, and all 3 species made more turns in clear-cuts than in forests. Habitat selection by southern toads did not vary according to body size, sex, or the environmental cues we measured. However, marbled salamanders were more likely to enter clear-cuts when soil moisture was high, and southern leopard frogs were more likely to enter clear-cuts when relative humidity and air temperature were higher in the clear-cut than in adjacent forest. Although we found evidence of reduced habitat permeability of clear-cuts for southern leopard frogs and southern toads, none of the species exhibited strong behavioral avoidance of the small (4-ha) clear-cuts in our study. Further studies of long-term habitat use and the potential physiological and other costs to individuals in altered forests are needed to understand the effects of forest management on population persistence. To reduce potentially detrimental effects of clear-cutting on amphibians in the Southeast, wildlife managers should consider the vagility and behavior of species of concern, especially in relation to the size of planned harvests adjacent to breeding sites.     

The Interplay of Habitat and Seed Type on Scatterhoarding Behavior in a Fragmented Afromontane Forest Landscape

Scatterhoarding by rodents, whereby seeds are collected and stored for later consumption, can result in seed dispersal. Seeds may be covered in litter on the forest floor (cached) or buried. This is particularly so in the Neotropics for large, nutritious seeds, and where primary dispersers are rare or missing. In African forests, contemporary anthropogenic pressures such as hunting, forest degradation, and fragmentation are contributing toward major declines in large frugivores, yet the potential for scatterhoarding to mitigate this loss is largely unknown. In this study, we used thread‐marked seed to explore the balance between seed predation and dispersal by rodents in Afromontane forest. We studied two tree species in three habitats: (1) continuous forest; (2) continuous forest edge, and (3) small, degraded riparian forest patches. We found that seed removal rates were high and almost the same in all three habitats for both tree species, but that the predation/dispersal balance differed among habitats. In continuous forest, more seeds of each species were scatterhoarded than depredated, and rates of scatterhoarding differed between the two species. In all habitats, burying seeds up to 2 cm belowground was more common than caching. Distances seeds were moved was approximately five times greater in continuous forest than in forest edge or riparian patches. We found strong evidence to suggest that the African pouched rat, Cricetomys sp. nov was responsible for the scatterhoarding.     

The Conservation Value of Traditional Rural Landscapes: The Case of Woodpeckers in Transylvania,Romania

Land use change is a major threat to global biodiversity. Forest species face the dual threats of deforestation and intensification of forest management. In regions where forests are under threat, rural landscapes that retain structural components of mature forests potentially provide valuable additional habitat for some forest species. Here, we illustrate the habitat value of traditional wood pastures for a woodpecker assemblage of six species in southern Transylvania, Romania. Wood pastures are created by long-term stable silvo-pastoral management practices, and are composed of open grassland with scattered large, old trees. Because of their demanding habitat requirements, woodpeckers share habitat with many other bird species, and have been considered as possible indicator species for bird species diversity. We first compared woodpecker assemblages between forests and wood pastures. Second, we grouped features of wood pastures into three spatial contexts and addressed how these features related to the occurrence of three woodpecker species that are formally protected. Woodpecker species composition, but not the number of species, differed between forests and wood pastures, with the green woodpecker occurring more commonly in wood pastures, and the lesser spotted woodpecker more commonly in forests. Within wood pastures, the intermediate context (especially surrounding forest cover) best explained the presence of the grey-headed and middle spotted woodpecker. By contrast, variables describing local vegetation structure and characteristics of the surrounding landscape did not affect woodpecker occurrence in wood pastures. In contrast to many other parts of Europe, in which several species of woodpeckers have declined, the traditional rural landscape of Transylvania continues to provide habitat for several woodpecker species, both in forests and wood pastures. Given the apparent habitat value of wood pastures for woodpeckers we recommend wood pastures be explicitly considered in relevant policies of the European Union, namely the Habitats Directive and the EU Common Agricultural Policy.     

Coexistence of Habitat Specialists and Generalists in Metapopulation Models of Multiple-Habitat Landscapes

In coarse-grained environments specialists are generally predicted to dominate. Empirically, however, coexistence with generalists is often observed. We present a simple, but previously unrecognized, mechanism for coexistence of a habitat generalist and a number of habitat specialist species. In our model all species have a metapopulation structure in a landscape consisting of patches of different habitat types, governed by local extinction and colonization. Each specialist is limited to its specific type of habitat. The generalist can use more types of habitat, has a lower local competitive ability but can exploit patches left open by the specialists. Our modeling shows that coexistence is easily possible. The mechanism amounts to a colonization/competition trade-off at the landscape level, where the colonization advantage of the inferior competitor does not arise from a higher colonization rate but from its ability to use more types of habitat. Habitat availability has to be intermediate: when there are few patches of each habitat, only the generalist is able to maintain itself and when there are many patches, high propagule pressure of the specialists excludes the generalist. Habitat selection or temporal variations in relative habitat quality are not necessary for coexistence. Increased niche-width, colonization rate or local competitive ability of the generalist enhances its performance compared to the specialists. Various types of habitat degradation favour generalism. When able to use a broad range of habitats, generalists can generate so much propagule pressure that only a low level of local competitive ability is needed to globally exclude the specialists. Hence, in a reversal of the original problem, the question is why there are so many specialist metapopulations?     

The Policy Terrain in Protected Area Landscapes: Challenges for Agroforestry in Integrated Landscape Conservation

Integrated ecosystem and landscape approaches to conservation are moving from concept to practice in many parts of the developing world. Agroforestry – the deliberate management of trees on farms and in agricultural landscapes – is emerging as one of the most promising approaches to enhance and stabilize rural livelihoods, while reducing pressure on protected areas, enhancing habitat for some wild species, and increasing connectivity of landscape components. For the potential of agroforestry to be effectively harnessed, however, the policy and institutional environment needs to provide farmers with clear incentives to plant and protect trees that contribute to both ecosystem function and rural livelihoods. This paper analyzes the policy terrain affecting agroforestry around protected areas in five very different contexts across Sub-Saharan Africa, finding both expected and unexpected similarities. Across the sites in Uganda, Cameroon and Mali, the study revealed a rough policy terrain for agroforestry – systemic market constraints, contradictions between development approaches and conservation objectives, and inconsistencies in institutional and regulatory frameworks. Making the conservation landscape approach more effective will require that both agriculturalists and conservation planners have much greater appreciation for the conservation and livelihood potential of agroforestry.     

基于地形因子的藏狐生境评价及其空间容纳量的估算

依据藏狐的“出现点”数据,基于藏狐对家域内地形因子的利用,作者对青海省都兰县沟里乡野生藏狐的生境质量进行初步评价,并在基于个体藏狐最小空间需求的基础上,估算了研究地区的空间环境容纳量。 选择海拔、坡度、坡位和地形起伏度等4个主要的地形因子,应用Bonferroni置信区间比较藏狐对各因子的利用及其可获得性来建立单个因子评价准则,并依据各因子的分布特征进行综合生境评价。研究结果：藏狐最适宜的海拔高度为4 050～4 300 m,坡度为5～20°,坡位为上坡位和下坡位;藏狐对地形起伏度因子没有明显的选择性。根据藏狐对不同生境因子的利用,及不同藏狐个体生境利用的一致性,建立的综合评价准则为：X i=（X²_海拔×X²_坡位×X_坡度×X_{地形起伏度}）^1/6。研究地区内适宜性区域面积约为17.4 km²,占总研究地区面积的38.8%,其中最适宜生境仅0.4 km²。藏狐家域面积从2.53 ～4.99 km²不等,不同个体间家域重叠指数（OI）从0.16～0.66不等。藏狐的最小空间需求为2.09～3.55 km²,研究地区藏狐的空间容纳量为7～12只。根据生境资源现状及监测结果表明,研究地区的藏狐种群数量保持稳定。     

Can Economic Incentives Resolve Conservation Conflict: The Case of Wild Deer Management and Habitat Conservation in the Scottish Highlands

Market-based economic incentives are increasingly perceived as a cost-effective approach to biodiversity conservation but empirical evidence to substantiate this claim is lacking. Using both qualitative and quantitative data analysis this paper investigates the potential role of market incentives to increase venison production as a mechanism to resolve conflicts over wild red deer management in the Scottish Highlands. Our analysis suggests the approach is unlikely to be effective because investments in venison production would bring conflict with more important non-pecuniary objectives of landownership such as ‘sporting quality’ and ‘exclusivity’. At a broader level we urge caution when considering the deployment of economic instruments to resolve contemporary conservation conflicts where profit maximisation is not the dominant objective and/or where the target group is extremely wealthy.     

Space Use and Habitat Selection by Bobcats in the Fragmented Landscape of South-Central Iowa

Abstract: Historically, bobcats (Lynx rufus) were found throughout the Corn Belt region, but they nearly disappeared from this area due to habitat loss and unregulated harvest that occurred during the century after European settlement. Reports of bobcat occurrences have been increasing in Iowa, USA, and biologists would like to understand the mechanisms enabling bobcats to recolonize this fragmented agricultural landscape. We determined space use and habitat selection of bobcats by radiocollaring 68 bobcats in south-central Iowa during 2003–2006. We triangulated 12,966 locations and recovered an additional 1,399 3-dimensional locations from Global Positioning System collars. We used a fixed kernel estimator to calculate 95% utilization distributions (UDs) for home ranges and 50% UDs for cores. Annual home range area of males (x̄ = 58.6 km², 95% CI = 49.2–69.9) was nearly 3 times that of females (x̄=19.9 km², 95% CI = 17.0–23.3). Females used smaller home ranges during April-September when they were suspected to have kittens with them (x̄ = 16.8 km², 95% CI = 13.7–20.7), as compared to October-March (x̄ = 24.1 km², 95% CI = 19.0–30.7), whereas home ranges of males did not differ between seasons. Similarly, core area of males (x̄ = 7.7 km², 95% CI = 6.2–9.6) was larger than that of females (x̄ = 2.3 km², 95% CI = 1.9–2.7). Females used significantly smaller cores in April-September (x̄ = 1.8 km², 95% CI = 1.4–2.3) as compared to October-March (x̄ = 2.8 km², 95% CI = 2.2–3.7), whereas males did not. For both sexes, compositional analysis indicated that forest habitat was ranked higher than all other habitat classes at both the landscape and local scale. Standardized habitat selection ratios illustrate that female and male bobcats selected forest habitat about twice as frequently as any other habitat class, including grassland and Conservation Reserve Program land. Predictive models indicated that home range and core area was smaller in landscapes where perennial forest and grassland habitats were less fragmented. Predictive models indicated home ranges were more irregular in shape in landscapes where row crop patches were less aggregated within home ranges. Our results have practical implications for wildlife managers regarding expected bobcat habitat use and distribution as the species becomes more abundant in the agricultural landscape of the Midwest.     

Biogeography of the Primates of Guyana: Effects of Habitat Use and Diet on Geographic Distribution

Species that exploit a wide range of resources or habitats (generalists) tend to be widely distributed, whereas species that exploit a narrow range of resources or habitats (specialists) often have a limited distribution. The distribution patterns are thought to result from specialists using relatively smaller habitats than those exploited by generalists. I used data from 1,725 km of primate surveys that I conducted in Guyana to test these hypotheses. Habitat breadth is the total number of different habitat types occupied by each species. I used the total number of different food categories exploited by each species to measure dietary breadth. Geographic range size is correlated with habitat breadth but not with dietary breadth or body size for the 8 primate species in Guyana. Habitat generalists—red howlers and wedge-capped capuchins—range into all habitats. Habitat specialists—spider monkeys, brown bearded sakis, and golden-handed tamarins—range only into large habitats. Habitat generalists tend to be dietary type specialists in Guyana. I suggest that only habitat generalists can subsist on the low-quality foods in small habitats in Guyana. Conversely, habitat specialists tend to be dietary type generalists in Guyana. They must feed on a variety of food types in large habitats. However, using the number of food categories exploited as a measure of dietary breadth may be only a weak aspect of multidimensional niche. Researchers testing biogeographic hypotheses associated with dietary breadth should consider including multivariate indicators of both the types of food categories eaten and the number of plant species exploited.