Effects of Trophy Hunting on Lion and Leopard Populations in Tanzania

Abstract: Tanzania holds most of the remaining large populations of African lions (Panthera leo) and has extensive areas of leopard habitat (Panthera pardus), and both species are subjected to sizable harvests by sport hunters. As a first step toward establishing sustainable management strategies, we analyzed harvest trends for lions and leopards across Tanzania's 300,000 km² of hunting blocks. We summarize lion population trends in protected areas where lion abundance has been directly measured and data on the frequency of lion attacks on humans in high‐conflict agricultural areas. We place these findings in context of the rapidly growing human population in rural Tanzania and the concomitant effects of habitat loss, human‐wildlife conflict, and cultural practices. Lion harvests declined by 50% across Tanzania between 1996 and 2008, and hunting areas with the highest initial harvests suffered the steepest declines. Although each part of the country is subject to some form of anthropogenic impact from local people, the intensity of trophy hunting was the only significant factor in a statistical analysis of lion harvest trends. Although leopard harvests were more stable, regions outside the Selous Game Reserve with the highest initial leopard harvests again showed the steepest declines. Our quantitative analyses suggest that annual hunting quotas be limited to 0.5 lions and 1.0 leopard/1000 km² of hunting area, except hunting blocks in the Selous Game Reserve, where harvests should be limited to 1.0 lion and 3.0 leopards/1000 km².     

Conservation Implications of Drastic Reductions in the Smallest and Most Isolated Populations of Giant Pandas

Abstract: In conservation biology, understanding the causes of endangerment is a key step to devising effective conservation strategies. We used molecular evidence (coalescent simulations of population changes from microsatellite data) and historical information (habitat and human population changes) to investigate how the most‐isolated populations of giant pandas (Ailuropoda melanoleuca) in the Xiaoxiangling Mountains became highly endangered. These populations experienced a strong, recent demographic reduction (60‐fold), starting approximately 250 years BP. Explosion of the human population and use of non‐native crop species at the peak of the Qing Empire resulted in land‐use changes, deforestation, and habitat fragmentation, which are likely to have led to the drastic reduction of the most‐isolated populations of giant pandas. We predict that demographic, genetic, and environmental factors will lead to extinction of giant pandas in the Xiaoxiangling Mountains in the future if the population remains isolated. Therefore, a targeted conservation action—translocation—has been proposed and is being implemented by the Chinese goverment.     

A case study of sustainable development in the Sistan-Balochistan province of Iran

Sustainable development is a key factor for economic growth in the twenty-first century. It can be achieved in two stages, the first stage is to conserve and protect forest and other parts of the environment and the second stage is to have an appropriate economic plan to produce more agricultural and industrial goods. This investigation evaluates a possible method for sustainable development in the Sistan-Balochistan Province of Iran. Sistan-Balochistan has the lowest economic growth rate due to severe geographical and environmental constrains.     

Effects of Road Mortality and Mitigation Measures on Amphibian Populations

Road mortality is a widely recognized but rarely quantified threat to the viability of amphibian populations. The global extent of the problem is substantial and factors affecting the number of animals killed on highways include life‐history traits and landscape features. Secondary effects include genetic isolation due to roads acting as barriers to migration. Long‐term effects of roads on population dynamics are often severe and mitigation methods include volunteer rescues and under‐road tunnels. Despite the development of methods that reduce road kill in specific locations, especially under‐road tunnels and culverts, there is scant evidence that such measures will protect populations over the long term. There also seems little likelihood that funding will be forthcoming to ameliorate the problem at the scale necessary to prevent further population declines. Efectos de la Mortalidad en Carreteras y Medidas de Mitigación en Poblaciones de Anfibios Beebee     

Effects of an Invasive Plant on Population Dynamics in Toads

When populations decline in response to unfavorable environmental change, the dynamics of their population growth shift. In populations that normally exhibit high levels of variation in recruitment and abundance, as do many amphibians, declines may be difficult to identify from natural fluctuations in abundance. However, the onset of declines may be evident from changes in population growth rate in sufficiently long time series of population data. With data from 23 years of study of a population of Fowler's toad (Anaxyrus [ = Bufo] fowleri) at Long Point, Ontario (1989–2011), we sought to identify such a shift in dynamics. We tested for trends in abundance to detect a change point in population dynamics and then tested among competing population models to identify associated intrinsic and extrinsic factors. The most informative models of population growth included terms for toad abundance and the extent of an invasive marsh plant, the common reed (Phragmites australis), throughout the toads’ marshland breeding areas. Our results showed density‐dependent growth in the toad population from 1989 through 2002. After 2002, however, we found progressive population decline in the toads associated with the spread of common reeds and consequent loss of toad breeding habitat. This resulted in reduced recruitment and population growth despite the lack of significant loss of adult habitat. Our results underscore the value of using long‐term time series to identify shifts in population dynamics coincident with the advent of population decline. Efectos de una Planta Invasora sobre las Dinámica Poblacional de Sapos     

Use of Spatial Capture‐Recapture Modeling and DNA Data to Estimate Densities of Elusive Animals

Abstract: Assessment of abundance, survival, recruitment rates, and density (i.e., population assessment) is especially challenging for elusive species most in need of protection (e.g., rare carnivores). Individual identification methods, such as DNA sampling, provide ways of studying such species efficiently and noninvasively. Additionally, statistical methods that correct for undetected animals and account for locations where animals are captured are available to efficiently estimate density and other demographic parameters. We collected hair samples of European wildcat (Felis silvestris) from cheek‐rub lure sticks, extracted DNA from the samples, and identified each animals’ genotype. To estimate the density of wildcats, we used Bayesian inference in a spatial capture‐recapture model. We used WinBUGS to fit a model that accounted for differences in detection probability among individuals and seasons and between two lure arrays. We detected 21 individual wildcats (including possible hybrids) 47 times. Wildcat density was estimated at 0.29/km² (SE 0.06), and 95% of the activity of wildcats was estimated to occur within 1.83 km from their home‐range center. Lures located systematically were associated with a greater number of detections than lures placed in a cell on the basis of expert opinion. Detection probability of individual cats was greatest in late March. Our model is a generalized linear mixed model; hence, it can be easily extended, for instance, to incorporate trap‐ and individual‐level covariates. We believe that the combined use of noninvasive sampling techniques and spatial capture‐recapture models will improve population assessments, especially for rare and elusive animals.     

A Framework for Developing Objective and Measurable Recovery Criteria for Threatened and Endangered Species

For species listed under the U.S. Endangered Species Act (ESA), the U.S. Fish and Wildlife Service and National Marine Fisheries Service are tasked with writing recovery plans that include “objective, measurable criteria” that define when a species is no longer at risk of extinction, but neither the act itself nor agency guidelines provide an explicit definition of objective, measurable criteria. Past reviews of recovery plans, including one published in 2012, show that many criteria lack quantitative metrics with clear biological rationale and are not meeting the measureable and objective mandate. I reviewed how objective, measureable criteria have been defined implicitly and explicitly in peer‐reviewed literature, the ESA, other U.S. statutes, and legal decisions. Based on a synthesis of these sources, I propose the following 6 standards be used as minimum requirements for objective, measurable criteria: contain a quantitative threshold with calculable units, stipulate a timeframe over which they must be met, explicitly define the spatial extent or population to which they apply, specify a sampling procedure that includes sample size, specify a statistical significance level, and include justification by providing scientific evidence that the criteria define a species whose extinction risk has been reduced to the desired level. To meet these 6 standards, I suggest that recovery plans be explicitly guided by and organized around a population viability modeling framework even if data or agency resources are too limited to complete a viability model. When data and resources are available, recovery criteria can be developed from the population viability model results, but when data and resources are insufficient for model implementation, extinction risk thresholds can be used as criteria. A recovery‐planning approach centered on viability modeling will also yield appropriately focused data‐acquisition and monitoring plans and will facilitate a seamless transition from recovery planning to delisting. Un Marco de Referencia para Desarrollar Criterios de Recuperación Objetivos y Medibles para Especies Amenazadas y en Peligro     

Specific Features of the Population Ecology of Creeping Thistle, Cirsium arvense(L.) Scop. s. l.

Two populations of creeping thistle (Cirsium arvense) growing in a field uncultivated for many years and on the sloping bank of an artificial pond were studied with respect to the demographic and chemical composition. The results showed that the contents of some elements in plants depend on specific features of the soil and plant population parameters (abundance, biomass, and ontogenetic composition). Some indices of the content of mineral substances in the population and soil proved to be difficult to interpret unambiguously.     

Influence of a Threatened‐Species Focus on Conservation Planning

Abstract: Conservation efforts at local, regional, and global scales often focus on threatened species despite recent calls to adopt more equitable and potentially more economically rational approaches. Critics contend that conservation planning centered only on threatened species fails to deliver cost‐efficient conservation outcomes. We explored how planning to preserve threatened mammal species would influence the efficiency and effectiveness of conservation investments in East Kalimantan, Indonesia. We found that the explicit protection of threatened species delivered cost‐efficient outcomes in this situation, afforded adequate protection to over 90% of those species not yet considered endangered, and contributed to the partial protection of the remainder. We used Marxan, a conservation planning tool, to determine the frequency that planning units are selected in efficient reserve systems and assessed the relative risk of deforestation of each planning unit. Our methods allowed us to identify areas of the region that require the most urgent conservation action.     

Inbreeding Depression Accumulation across Life‐History Stages of the Endangered Takahe

Abstract: Studies evaluating the impact of inbreeding depression on population viability of threatened species tend to focus on the effects of inbreeding at a single life‐history stage (e.g., juvenile survival). We examined the effects of inbreeding across the full life‐history continuum, from survival up to adulthood, to subsequent reproductive success, and to the recruitment of second‐generation offspring, in wild Takahe ( Porphyrio hochstetteri ) by analyzing pedigree and fitness data collected over 21 breeding seasons. Although the effect size of inbreeding at individual life‐history stages was small, inbreeding depression accumulated across multiple life‐history stages and ultimately reduced long‐term fitness (i.e., successful recruitment of second‐generation offspring). The estimated total lethal equivalents (2B) summed across all life‐history stages were substantial (16.05, 95% CI 0.08–90.8) and equivalent to an 88% reduction in recruitment of second‐generation offspring for closely related pairs (e.g., sib–sib pairings) relative to unrelated pairs (according to the pedigree). A history of small population size in the Takahe could have contributed to partial purging of the genetic load and the low level of inbreeding depression detected at each single life‐history stage. Nevertheless, our results indicate that such “purged” populations can still exhibit substantial inbreeding depression, especially when small but negative fitness effects accumulate across the species’ life history. Because inbreeding depression can ultimately affect population viability of small, isolated populations, our results illustrate the importance of measuring the effects of inbreeding across the full life‐history continuum.