Predator abundance in relation to small game management in southern Portugal: conservation implications

The interaction between hunting interests and legally protected predators is often a contentious conservation problem, requiring detailed understanding of predator responses to game management. This issue was addressed in southern Portugal in a treatment-control natural experiment, whereby the abundances of small game, corvids, birds of prey and carnivores were compared in 12 game estates (>500 ha) and 12 matching areas with similar sizes and land uses but no game management. European rabbits (Oryctolagus cuniculus), Iberian hares (Lepus granatensis) and, less so, red-legged partridges (Alectoris rufa) were far more numerous in game estates than elsewhere. Among legally controlled species, there were less Eurasian jays (Garrulus glandarius) but more red foxes (Vulpes vulpes) in game estates, though the latter were primary targets of predator culling. Fox abundance within game estates varied inversely with an index of management intensity (density of small game feeding sites) and increased along with hare abundance. As for protected species, only common kestrels (Falco tinnunculus) and genets (Genetta genetta) were fewer in game estates. The abundance of raptors within game estates varied inversely with gamekeeper density, whereas that of common buzzards (Buteo buteo) increased along with rabbit abundance. Overall, there was little evidence that game management reduced local predator abundances, except in the most intensively managed estates. Game estates provided concentrations of prey that was scarce elsewhere, which may have favoured increased abundances of some predators. Further investigations are needed to find out whether high prey densities may attract predators to game estates with increased mortality risk, which may thus become population sinks for protected species.     

Impact of game hunting by the Kayapó of south-eastern Amazonia: implications for wildlife conservation in tropical forest indigenous reserves

Indigenous forest reserves represent approximately one fifth of Brazilian Amazonia and pose enormous challenges for sustainable natural resource management by native Amazonians. In collaboration with the Kayapó Indians of A’Ukre of southeastern Amazonia, we obtained a game harvest profile of over 1360 forest vertebrates consumed at this village over a 20-month period, including 743 mammals, 361 forest tortoises and 256 birds from a minimum of 42 game species. This amounted to a total of 13,775 kg of game animals harvested over the entire study (mean = 26.2 kg d⁻¹). We also obtained some 450 km of line transect census data of midsized to large-bodied vertebrates within the core hunting catchment of this village and in an unhunted but otherwise comparable site upriver of A’Ukre. Population density estimates of 16 of the 18 species censused were significantly depressed by hunting by central place foragers within the village catchment, and a number of harvest-sensitive prey species showed clear evidence of local depletion. For the time being, however, we can conclude that hunting was sustainable at the landscape scale largely because source-sink dynamics in the context of low village catchment density is made possible by large surrounding tracts of primary forest that remain unharvested or underharvested.     

Estimating the influence of land management change on weed invasion potential using expert knowledge

Aim To develop and test a general framework for estimating weed invasion potential (suitability and susceptibility) that utilized expert knowledge of dispersal, establishment and persistence and considered the influence of land management. Location The semi‐arid Desert Channels Region of Queensland, Australia (476,000 km²). Methods We developed a general framework that integrated knowledge and empirical data of the environmental and land management variables influencing the dispersal, establishment and persistence of the invasive shrub parkinsonia (Parkinsonia aculeata) using a Bayesian network linked to a Geographic Information System (GIS). We evaluated the influence of different land management scenarios on landscape suitability for parkinsonia. Model performance was assessed by comparing predicted landscape suitability with mapped parkinsonia locations and estimated parkinsonia density. Results Our predictions of moderate to high suitability corresponded reasonably well with mapped parkinsonia locations (71% match) and areas of common to abundant estimated density (92% match). They also suggested that parkinsonia has not reached its potential distribution within the study region. Under current land management conditions, 77,000 km² of land was found to be highly or moderately suitable for parkinsonia. Scenario analysis indicated that maintaining moderate herbaceous ground cover levels, and using sheep to browse juvenile parkinsonia, reduced the predicted moderate to high suitability area to 27,000 km², offering a potential management strategy for limiting parkinsonia invasion. Main conclusions Weed invasion potential can be reasonably estimated using expert knowledge of dispersal, establishment and persistence, integrated using a Bayesian network linked to a GIS. This modelling approach can be an alternative to process‐based and phenomenological modelling, which can be problematic for modelling new and emerging weed invasions, particularly where data are patchy. The modelling approach also allows the influence of land management change on invasion potential to be investigated through scenario analysis.     

Risk management decisions for pesticides and threatened and endangered species: The role of uncertainty analysis

Despite data gaps and information shortfalls, government agencies in the United States are expected to produce timely and defensible decisions to regulate pesticide use under the Federal Insecticide, Fungicide, and Rodenticide Act and in compliance with the Endangered Species Act. The decision to register a pesticide is predicated on a conclusion that no unreasonable effects will accrue to the environment, including threatened and endangered species. We recognize that the definition of acceptable risk is a policy judgment stemming from legislative language and judicial interpretation. However, a common risk assessment approach with similar technical underpinnings and a high degree of transparency used by all the agencies would be cost effective and more likely to achieve consensus among interested parties. Quantitative probabilistic risk assessment (PRA) methods can be used to develop risk estimates and to describe the level of confidence in these estimates. PRA methods can also differentiate among the contributions of natural stochasticity, measurement variability, and lack of knowledge. Because this approach enhances transparency and increases understanding of the implications of limited data sets and associated assumptions, we encourage the appropriate agencies to implement PRA methods as a means of reaching common ground when assessing risks of pesticides to listed species.     

The effects of deforestation on wildlife along the transamazon highway

Hunting, although prohibited, is widely practiced by the rural inhabitants settled along the Transamazon highway. In 1997 and 2000, we investigated subsistence hunting in Uruará, a township located on an Amazonian pioneer front (Brazil). We analyze hunting practices, game yield, hunting efficiency and their relation to forest coverage rate. The hunting methods were stand hunting (55.5%) and beating (44.5%). Paca (Agouti paca), tatus (Dasypus novemcinctus and D. septemcinctus), and collared peccary (Pecari tajacu) were the most frequently hunted species, supplying 68% of the gross game weight. Beating was significantly more efficient than stand hunting (3 vs. 1.9 kg/hunter/h, Mann–Whitney U test, P=0.02). Hunting territories were classified in three categories according to forest coverage rate. The higher the forest coverage rate the larger was the harvested species and the more efficient the hunter (Kruskal–Wallis test P=0.01). Considering the ecological and demographic changes in this pioneer settlement, development of a viable plan for game management and forest preservation is of great importance.     

The impact of brodifacoum on non-target wildlife: gaps in knowledge

To assess the effect of possum browse on plant growth, an index of the amount of foliage on about 50 trees of Fuchsia excorticata and the number of trees that died or were completely defoliated was measured at five sites in South Westland over 5 years. This index was compared to possum density indices taken at each site each year. At one site, possums were reduced from a high density about 6 months before the final measurement. The degree of defoliation of fuchsia was significantly related to the density of possums at each site. Possums defoliate and kill fuchsia within two years once the catch-rate index of their density exceeds about 25%. However, this impact can be halted and quickly reversed by reducing possum density.     

Conservation of wildlife populations: factoring in incremental disturbance

Progressive anthropogenic disturbance can alter ecosystem organization potentially causing shifts from one stable state to another. This potential for ecosystem shifts must be considered when establishing targets and objectives for conservation. We ask whether a predator–prey system response to incremental anthropogenic disturbance might shift along a disturbance gradient and, if it does, whether any disturbance thresholds are evident for this system. Development of linear corridors in forested areas increases wolf predation effectiveness, while high density of development provides a safe‐haven for their prey. If wolves limit moose population growth, then wolves and moose should respond inversely to land cover disturbance. Using general linear model analysis, we test how the rate of change in moose (Alces alces) density and wolf (Canis lupus) harvest density are influenced by the rate of change in land cover and proportion of land cover disturbed within a 300,000 km² area in the boreal forest of Alberta, Canada. Using logistic regression, we test how the direction of change in moose density is influenced by measures of land cover change. In response to incremental land cover disturbance, moose declines occurred where <43% of land cover was disturbed; in such landscapes, there were high rates of increase in linear disturbance and wolf density increased. By contrast, moose increases occurred where >43% of land cover was disturbed and wolf density declined. Wolves and moose appeared to respond inversely to incremental disturbance with the balance between moose decline and wolf increase shifting at about 43% of land cover disturbed. Conservation decisions require quantification of disturbance rates and their relationships to predator–prey systems because ecosystem responses to anthropogenic disturbance shift across disturbance gradients.     

The role of disorder in interaction networks: a structural analysis

Recent studies have emphasized the value of including structural information into the topological analysis of protein networks. Here, we utilized structural information to investigate the role of intrinsic disorder in these networks. Hub proteins tend to be more disordered than other proteins (i.e. the proteome average); however, we find this only true for those with one or two binding interfaces (‘single’‐interface hubs). In contrast, the distribution of disordered residues in multi‐interface hubs is indistinguishable from the overall proteome. Surprisingly, we find that the binding interfaces in single‐interface hubs are highly structured, as is the case for multi‐interface hubs. However, the binding partners of single‐interface hubs tend to have a higher level of disorder than the proteome average, suggesting that their binding promiscuity is related to the disorder of their binding partners. In turn, the higher level of disorder of single‐interface hubs can be partly explained by their tendency to bind to each other in a cascade. A good illustration of this trend can be found in signaling pathways and, more specifically, in kinase cascades. Finally, our findings have implications for the current controversy related to party and date‐hubs.     

Density dependence: Applications in wildlife management

Knowledge of density-dependent processes is regarded as important for making decisions on the management of wildlife populations. Using published data on ungulates and upland game birds, we discuss density-dependent effects on population growth, harvest management under the logistic model, and management to increase or decrease survival and production. Empirical data show density-dependent growth for white-tailed deer (Odocoileus virginianus), reindeer (Rangifer tarandus), ring-necked pheasants (Phasianus colchicus), and northern bobwhites (Colinus virginianus), although the logistic model provided, at best, an approximation of growth. Managing harvest according to logistic theory is rare for ungulates and upland game; we suspect this owes to scarce data on population growth and complexity in density-dependent processes. Under density dependence, managing to increase production or survival may be self-defeating because an increase in 1 demographic variable entails a decrease in the other for sustaining populations (λ = 1). The problem can be addressed by providing space for population growth (λ > 1), at least until growth re-establishes the density-dependent response (λ = 1). © 2012 The Wildlife Society.     

Determinants of uncertainty in wildlife responses to human disturbance

Outdoor recreation is increasing in intensity and space. Areas previously inaccessible are now being visited by ever‐growing numbers of people, which increases human–wildlife encounters across habitats. This has raised concern among researchers and conservationists as, even in non‐aggressive encounters, animals often perceive humans as predators and mount physiological and behavioural responses that can have negative consequences. However, despite all the research in recent decades, not many general patterns have emerged, especially at the level of populations, and many studies have yielded seemingly contradictory or inconclusive results. We argue that this is partly due to incomplete knowledge of the number and complexity of factors that may modulate the responses of animals. Thus, we aim to provide a conceptual approach intended to highlight the reasons that make it difficult to detect general patterns. We present a comprehensive compilation of factors modulating animal responses to humans at increasing levels (from sensory detection and immediate behavioural and physiological reactions, to changes in fitness and population trends), which may help understanding the uncertainty in the patterns. We observed that there are many modulating factors, which can be categorized as reflecting characteristics of the recreational activity itself (e.g. intensity of human presence), of the animals concerned (e.g. age or antipredatory strategy), and of the spatio‐temporal context (e.g. habitat or timing of the encounter). Some factors appear to have non‐linear and complex effects, which, if not considered, may lead to erroneous conclusions. Finally, we conclude that the difficulty in finding general patterns will be amplified at higher levels (i.e. at the level of populations), since as we proceed from one level to the next, the number of potential modulating factors accumulates, adding noise and obscuring direct associations between recreation and wildlife. More comprehensive knowledge about which (and how) factors affect animal responses across levels will certainly improve future research design and interpretation, and thus, our understanding of human recreational impacts on wildlife.     

Age structure: an indicator to monitor populations of large herbivores

Most populations of large herbivores are hunted over much of their distribution. The size of these populations over time must be monitored to detect responses to management actions and environmental changes. Here, I first review the limits in precision and accuracy of most methods used to estimate population size in wild herbivores. I then show how density-dependence of age structure can be used to monitor harvested populations, using simulated and empirical data. Accurate estimates of population size are difficult, costly in time and effort, and mostly impracticable at a large scale. Indices are widely used to monitor population size at a large scale, but are rarely tested, and assumptions of constant detection rates over years are questionable. In a recent approach, the effects of population density on habitat quality and individual performance were used as ecological indicators to infer changes in population size over time. Populations of large mammals are strongly age structured. In harvested populations, density-dependence and harvest affect age structure through changes in age-specific vital rates. Because age- and sex-specific vital rates are density-dependent, changes over time in age structure should reflect the response of population to changes in environmental conditions such as density and harvest rate. Time series of age-structure may be used as an ecological indicator to monitor harvested populations, and to infer their demographic trajectory, especially when used within a set of ecological indicators. However, attention needs to be paid in the use of ecological indicators because of the potential bias introduced in data collection by hunter selectivity.     

The role of expert systems in vegetation science

An area of artificial intelligence known as experts systems (or knowledge-based systems) is being applied in many areas of science, technology and commerce. It is likely that the techniques will have an impact on vegetation science and ecology in general. This paper discusses some of those impacts and concludes that the main effects will be in areas of applied ecology especially where ecological expertise is needed either quickly (e.g. disaster management) or across a wide range of ecological disciplines (e.g. land management decisions). Expert systems will provide ecologists with valuable tools for managing data and interacting with other fields of expertise. The impact of expert systems on ecological theory will depend on the degree to which deep knowledge (i.e. knowledge based on first principles rather than on more empirical rules) is used in formulating knowledge bases.     

Eliciting and integrating expert knowledge to assess the viability of the critically endangered golden sun‐moth Synemon plana

The critically endangered golden sun‐moth Synemon plana occurs in urban fringe areas of southeastern Australia that are currently experiencing rapid and extensive development. The urban fringe is a complex and uncertain environment in which to manage threatened species with the intersection of fragmented natural habitats, built environments and human populations generating novel, poorly understood interactions. In this context, management frameworks must incorporate ecological processes as well as social considerations. Here, we explore how biodiversity sensitive urban design might improve the fate of the golden sun‐moth, and threatened species generally, in urban fringe environments. We: (i) developed an expert‐informed Bayesian Belief Network model that synthesizes the current understanding of key determinants of golden sun‐moth population viability at sites experiencing urbanizing pressure; (ii) quantified the nature and strength of cause‐effect relationships between these factors using expert knowledge; and (iii) used the model to assess expectations of moth population viability in response to different combinations of management actions. We predict that adult survival, bare ground cover and cover of resource plants are the most important variables affecting the viability of golden sun‐moth populations. We also demonstrate the potential for biodiversity sensitive urban design as a complementary measure to conventional management for this species. Our findings highlight how expert knowledge may be a valuable component of conservation management, especially in addressing uncertainty around conservation decisions when empirical data are lacking, and how structured expert judgements become critical in supporting decisions that may help ameliorate extinction risks faced by threatened species in urban environments.     

Microbial ecology of Bacillus thuringiensis: fecal populations recovered from wildlife in Korea

A total of 34 fecal samples, collected from 14 species of wild mammals in Korea, were examined for the occurrence of Bacillus thuringiensis. The organism was detected in 18 (53%) samples. Among the three food-habit groups, herbivorous animals yielded the highest frequency (69%) of samples positive for B. thuringiensis, followed by omnivorous animals (50%). Of the six fecal samples from carnivorous animals, only one sample contained B. thurin giensis. Among 527 isolates belonging to the Bacillus cereus - B. thuringiensis group, 43 (8%) were assigned to B. thurin giensis on the basis of the formation of parasporal inclusions. Of the 43 isolates, 13 were serologically allocated to the nine H-antigenic serotypes: H3ad (serovar sumiyoshiensis), H15 (dakota), H17/27 (tohokuensis/ mexicanensis), H19 (tochigiensis), H21 (colmeri), H29 (amagiensis), H31/49 (toguchini/muju), H42 (jinghongiensis), and H44 (higo). Other isolates were untestable or untypable by the 55 reference H antisera available. Insecticidal activity was associated with 23% of the fecal populations: three isolates killed larvae of the silkworm, Bombyx mori (Lepidoptera), and seven exhibited larvicidal activity against the mosquito, Aedes aegypti (Diptera). There was no larvicidal activity against the three lepidopterous insects: Plutella xylostella, Spodoptera exigua, and Spodoptera litura. The overall results suggest that wild animals in Korea are in contact with naturally occurring B. thuringiensis at high frequencies through the daily food intake of plants.     

The role of wildlife science in wetland ecosystem restoration: Lessons from the Everglades

There has been little discussion of how and when to integrate wildlife science into ecological restoration projects. The recent emergence of wetland ecosystem restoration offers an opportunity to use wildlife science to increase the probability of a project being successful. This paper traces the evolution of wetland ecosystem restoration in North America and proposes three roles for wildlife science in wetland ecosystem restoration: (1) contribute to conceptual ecosystem models, (2) develop quantitative performance measures and restoration targets that track the progress of restoration, and (3) achieve social feasibility by sustaining long-term public support for a project. The extensive knowledge base for many species of wildlife makes them especially useful for contributing to conceptual ecosystem models. Wildlife species are often the subject of long-term monitoring and research because they have commercial value, are conspicuous, or have aesthetic appeal. Wildlife parameters can be good performance measures for large-scale restoration projects because some species integrate information over large spatial scales and are long-lived. Parameters associated with threatened or endangered wildlife species should get special consideration as performance measures because the information will meet multiple needs rather than just those of the conceptual ecosystem model. Finally, wetland ecosystem restoration projects need to sustain funding over decades to ensure the restored system is self-sustaining. Wildlife are a valued resource that can help achieve the social feasibility of a project by providing a way to communicate complex science in terms that society understands and values.