High Human Population Density Research Articles

Understanding species persistence for defining conservation actions: A management landscape for jaguars in the Atlantic Forest

Habitat models constitute useful instruments for understanding species-habitat interactions and can constitute helpful conservation tools. The Upper Paraná Atlantic Forest (UPAF) of South America still holds the world’s southernmost jaguar (Panthera onca) population. Our aims were: (i) to test several a priori hypotheses on the factors affecting jaguar persistence in this region, (ii) to map habitat suitability and identify areas with potentially conflicting habitat conditions, and (iii) to identify priority areas for management and improve the conservation initiatives for jaguars and the UPAF. Following an information-theoretic approach, we used presence records of jaguars and pseudo-absences in generalized linear models. We structured hypotheses into two groups which demand different management actions: land cover and human persecution. The best model of each group was used to develop a two-dimensional habitat model. Jaguar persistence was favoured by current and historical native forest cover, and hindered by human land uses. Protection favoured jaguar presence whereas human accessibility and high human population density had negative effects. The two-dimensional model suggests that <8% (20,670km2) of the landscape represents potential core areas for jaguars (good land-cover characteristics and low human persecution) and 11.8% (32,563km2) stands as potentially attractive sinks where good land-cover conditions conflict with high human persecution. Reduction of human persecution is urgently needed to increase the core areas for jaguars in this region, but improvement of land-cover conditions is important for sustaining the connectivity among jaguar populations that seem to be isolated in different areas of the UPAF.

Assessment of the flash flood potential of Bâsca River Catchment (Romania) based on physiographic factors

AbstractThe purpose of this paper is to identify areas with high flash-flood potential based on an evaluation of physiographic factors controlling the formation of surface runoff. The research method relies on the use of the Flash Flood Potential Index (FFPI), which incorporates physiographic characteristics from the catchment (terrain slope, profile curvature, land use and soil texture). The spatial distribution of the physiographic factors (which contribute to the creation, control and concentration within the drainage network of the overland flow) and the classified zoning of areas according to their hydrological response were achieved with GIS techniques. The results obtained show that physiographic factors on 227 sq km (29%) favor surface runoff on slopes and its localization towards the drainage network. Notably, the highest values of FFPI belong to the lower part of the catchment, where high human population density can be found, reflecting an increased vulnerability to floods and inundations of this area.

The international conservation importance of Welsh ‘waxcap’ grasslands

The large decline in plant and animal diversity of semi-natural grasslands resulting from the introduction of modern agricultural practices in the 1940’s has been well documented and such changes are also suspected of causing the decline in the abundance and diversity of macrofungi in these habitats. We conducted repeated surveys at 48 selected grassland sites around Wales to record the presence and abundance of fruitbodies (FBs) of grassland macrofungi belonging to the taxa Clavariaceae, Hygrocybe, Entoloma, Geoglossaceae, Dermoloma (also Porpoloma and Camarophyllopsis spp.) which are grouped collectively as fungi (acronym of group names) and considered typical of nutrient poor ‘waxcap’ grasslands. A total of 111 CHEGD species (of the ca. 200 species previously found in UK/Ireland) were recorded. That these included one species unknown to science, 14 new to Wales including two new to the UK attests to the extent of past under-recording. Phenological differences in fruiting were found between Entoloma and Hygrocybe spp., and patterns of occurrence at the sites correlated well with numbers of records from the Fungal Records Database of Britain and Ireland. The recent post-glacial history and high human population densities have generally resulted in lower levels of biological diversity in north-western Europe than in other parts of the world. Compared with current data from other European countries and globally, Welsh grasslands host particularly diverse macrofungal communities, yet the organisms continue to attract little attention from mainstream conservation bodies, whilst much conservation effort is lavished on species which are relatively common elsewhere.

Rapid paleohydrogical Holocene changes in the Amazon river and its implications on the carbon accumulation in floodplain lakes

The flood-pulse of the large rivers in Central Amazonia triggers ecological processes of the floodplain systems inducing a severe seasonality in the annual cycle between the aquatic and the terrestrial phase. The nutrient-rich floodplains (várzea) have the highest human population density in Amazonia and economic activities such as fishing, agriculture, pasture and timber extraction are directly associated with water-level fluctuations. The discharge of many tropical river systems responds to the El Niño-Southern Oscillation (ENSO) originating from the tropical Pacific. Several studies show a strong relationship between the flooding regime of Amazonian rivers and ENSO-indices, such as the meteorological Southern Oscillation Index (SOI) and sea surface temperatures (SSTs). During warm ENSO-phases (El Niño) flood-levels are lowered and aquatic phases are shortened, while high and prolonged flooding is associated to cold ENSO-phases (La Niña). Here we present retrospective forecasts of the maximum water level in Central Amazonia from 1903 to 2004 – generally occurring in the second half of June – and the length of the aquatic phase along the flood-gradient by models based on the SOI and SST anomalies of the El Niño 3.4 region in February, four months before its appearance. The forecast of the flood-pulse allows also predicting parameters correlated with the flood-pulse (e.g., tree growth, biogeochemical cycles) and increases the efficiency in planning and executing of economic activities by the human population (e.g., fishery, timber extraction, agriculture).

Effects of human mediated disturbances on exotic forest insect diversity in a Chilean mediterranean ecosystem

At the current rate of exchange of goods and people among geographic areas, the introduction of insect species into new habitats represents an increasing threat to insect diversity. The situation is especially acute in Mediterranean ecosystems where the high human population density incurs multiple sources of disturbance and high propagule pressure. In this study, we characterize the relationship between native and exotic forest insect richness and evaluate how human-mediated disturbances can influence this relationship in the Mediterranean central Chile. Exotic and native species richness were positively correlated across the study area, suggesting similar effect of environmental variables on both assemblages over large scales. When the effect of human-mediated disturbances was evaluated using generalized linear and additive models, we found that native richness, human population density and habitat diversity were the most important variables affecting exotic richness. Moreover, we detected strong nonlinearities in the effect of some variables. For instance, the influence of human population density on the exotic richness followed a threshold function, where below 1,000 hab/km2, the proportion of exotics in the community grew rapidly with increasing human density, but above this threshold density, human population did not produce further increases in exotic richness. Two important conclusions arise from these results: first, there is a positive effect of human-mediated disturbances on the exotic richness in central Chile, and second, the key role that human population density has on the invasibility of insect communities in rural and semi-rural Mediterranean areas.

Resource mapping and emergency preparedness to infectious diseases in human and animal populations in Kibaha and Ngorongoro districts, Tanzania

A rapid situation analysis was conducted in Kibaha and Ngorongoro districts in Tanzania to map resources as well as analysing emergency preparedness to infectious diseases in animal (domestic and wild) and human populations. Kibaha was chosen as a district close to a commercial city (Dar es Salaam) while Ngorongoro represented a remote, border district with high interactions between humans, domestic and wild animals. In this study, data on resources and personnel as well as emergency preparedness were collected from all wards (n = 22), human health facilities (n = 40) and livestock facilities in the two districts using interview checklists and questionnaires. Descriptive statistics for resources were calculated and mapped by district. Kibaha district had a higher human population density, more health workers, better equipped health facilities and better communication and transport systems. On the other hand, Ngorongoro had a higher population of livestock and more animal health facilities but a poorer ratio of animal health workers to livestock. The average ratio of health personnel to population in catchment areas of the health facilities was 1:147 (range of 1:17−1:1200). The ratio of personnel to human population was significantly higher in Kibaha (1:95) than in Ngorongoro (1:203) district (p = 0 &lt; 0.001). Considering the limited resources available to both human and animal health sectors and their different strengths and weaknesses there are opportunities for greater collaboration and resource-sharing between human and animal health for improved surveillance and emergency-preparedness.

Conservation in Sustainable-Use Tropical Forest Reserves

trialspecies,therelativemeritsofdifferentapproachesto ensure the long-term persistence of those species remain highly contentious. Most would agree, however, that both establishing protected areas and exercising some form of restraint on extraction of forest resources are among the most effective of all viable conservation measures. Deforestation, wildfires, logging, and hunting are among the leading drivers of species losses in tropical forests, and de facto or de jure protection from these threats can be conferred by either effective enforcement of regulations or physical remoteness. Attempts to assess conservation success of protected areasatlargescaleshaverestedprimarilyonconventional use of remote sensing to quantify spatial or temporal differences in rates of change in land cover due to deforestation and wildfires, rather than on empirical demographic or community-level metrics (Gaston et al. 2008). Q2 However, the former approaches fail to detect most types of subcanopy anthropogenic disturbances that also result, directly or indirectly, in species losses (Peres et al. 2006). Moreover, the effects of habitat loss and degradation on population extirpations and declines are nonlinear, so vegetation cover alone is rarely a robust proxy for the viability of terrestrial biotas. Remotesensing data show vast tracts of apparently intact tropical forests, but in reality levels of hunting and other forms of extraction in these areas are often unsustainable (Peres & Lake 2003). Fundamental questions yet to be answered include whether ostensibly intact protected areas retain full complements of forest species and how the extent of cryptic patterns of disturbance is related to human population density in both protected and unprotected areas. I considered the global to regional emergence of sustainable-use reserves, emphasizing the world’s largest tropical forest region, Amazonia. Sustainable-use reserves often have intermediate levels of disturbance, so I examined the degree of use of natural resources by resident communities and used human population density as a proxy for level of extraction. In both protected and unprotected areas, I also estimated responses of game vertebrate assemblages to hunting on the basis of the relative biomassextractedfromasubsetoftheforestfauna.Iused analysesofcovariance(ANCOVA)toexaminetheassociationbetweenhumandensityandgamebiomassharvested across different reserve categories. Finally, I considered the long-term capacity of sustainable-use forest reserves to maintain populations of all resident species.

Remote sensing analysis reveals habitat, dispersal corridors and expanded distribution for the Critically Endangered Cross River gorillaGorilla gorilla diehli

AbstractHabitat loss and fragmentation are among the major threats to wildlife populations in tropical forests. Loss of habitat reduces the carrying capacity of the landscape and fragmentation disrupts biological processes and exposes wildlife populations to the effects of small population size, such as reduction of genetic diversity and increased impact of demographic stochasticity. The Critically Endangered Cross River gorillaGorilla gorilla diehliis threatened in particular by habitat disturbance because its population is small and it lives in an area where high human population density results in intense exploitation of natural resources. We used remotely-sensed data to assess the extent and distribution of gorilla habitat in the Cross River region and delineated potential dispersal corridors. Our analysis revealed &gt; 8,000 km2of tropical forest in the study region, 2,500 km2of which is in or adjacent to areas occupied by gorillas. We surveyed 12 areas of forest identified as potential gorilla habitat, 10 of which yielded new records of gorillas. The new records expand the known range of the Cross River gorilla by &gt; 50%, and support genetic analyses that suggest greater connectivity of the population than previously assumed. These findings demonstrate that considerable connected forest habitat remains and that the area could potentially support a much larger gorilla population if anthropogenic pressures such as hunting could be reduced.

Landscapes as continuous entities: forest disturbance and recovery in the Albertine Rift landscape

Kibale National Park, within the Albertine Rift, is known for its rich biodiversity. High human population density and agricultural conversion in the surrounding landscape have created enormous resource pressure on forest fragments outside the park. Kibale presents a complex protected forest landscape comprising intact forest inside the park, logged areas inside the park, a game corridor with degraded forest, and forest fragments in the landscape surrounding the park. To explore the effect of these different levels of forest management and protection over time, we assessed forest change over the previous three decades, using both discrete and continuous data analyses of satellite imagery. Park boundaries have remained fairly intact and forest cover has been maintained or increased inside the park, while there has been a high level of deforestation in the landscape surrounding the park. While absolute changes in land cover are important changes in vegetation productivity, within land cover classes are often more telling of longer term changes and future directions of change. The park has lower Normalized Difference Vegetation Index (NDVI) values than the forest fragments outside the park and the formerly logged area—probably due to forest regeneration and early succession stage. The corridor region has lower productivity, which is surprising given this is also a newer regrowth region and so should be similar to the logged and forest fragments. Overall, concern can be raised for the future trajectory of this park. Although forest cover has been maintained, forest health may be an issue, which for future management, climate change, biodiversity, and increased human pressure may signify troubling signs.

Effects of anthropogenic disturbance on the abundance and size of epibenthic jellyfish Cassiopea spp.

Jellyfish blooms in pelagic systems appear to be increasing on a global scale because of anthropogenic impacts, but much less is known about the link between human activities and epibenthic jellyfish abundance. The aim of this study was to investigate whether the epibenthic jellyfish, Cassiopea spp., were found in greater abundance, and attained larger sizes, in coastal habitats adjacent to high human population densities compared to sites adjacent to uninhabited areas on Abaco Island, Bahamas. Cassiopea spp. were found to be significantly more dense and larger in areas with high human population densities. Ambient nutrient levels and nutrient content of seagrass were elevated in high human population density sites, and may be one mechanism driving higher abundance and size of Cassiopea spp. Cassiopea spp. may have important effects on community structure and ecosystem function in critical coastal ecosystems (e.g., seagrass beds), and their impacts warrant further study.

Public perceptions of jaguars Panthera onca, pumas Puma concolor and coyotes Canis latrans in El Salvador

High human population density, histories of social conflict, environmental change and negative social attitudes are crucial issues for large carnivore conservation and reintroductions, which may be influenced by human age and gender, animal size and behaviour. Jaguars and pumas are extinct in El Salvador, but conservation and reintroduction schemes are debated across Central and South America. This paper examines public attitudes in El Salvador towards the extinct jaguars and pumas, and the fairly common coyote. One hundred and thirteen people were contacted and classified according to age and gender in San Salvador, La Union, Ahuachapan, Apopa, San Miguel and Santa Ana. The majority of people believed: in the toleration and removal of carnivores rather than shooting; in the introduction of jaguars and pumas into rural and special areas and zoos; that more animal protection was necessary; that the animals were good for human life, yet dangerous to children. Pumas were seen as the most dangerous, followed by jaguars and coyotes, but in most cases all three were seen as similar. Women were less tolerant of large carnivores, were more sensitive to negative impacts, and were more afraid of the animals than men. Younger people were more tolerant, and saw less danger to other animals and people, and were more supportive of animal reintroductions. Gender was irrelevant in the trapping and removal, and shooting of animals, protection levels, reintroductions and dangers to people and cattle. Age was irrelevant to animal protection levels, dangers to people and impacts on human quality of life. These findings are important for conservation policy and environmental geography.

Predicting changes in the abundance of African wetland birds by incorporating abundance–occupancy relationships into habitat association models

AbstractAim To map changes in the abundance of African wetland birds using remotely derived habitat data. We show that abundance–occupancy relationships can be coupled with habitat association models to map changes in abundance. As conservation resources are more easily allocated when spatial and temporal patterns of abundance are known, our method provides guidance for conservation planning.Location Papyrus, Cyperus papyrus, swamps in east central Africa.Methods Presence/absence surveys of six bird species in 93 wetlands were used to construct models predicting probability of occurrence from habitat characteristics. Densities were then determined from surveys in 23 additional wetlands and modelled as functions of occurrence probability. We then used satellite imagery to derive habitat characteristics remotely in two time periods (1984–87 and 2000–03) and used the modelled relationships between (1) habitat and occupancy and (2) occupancy and density, to infer changes in abundance in all c. 30,000 wetlands within the study area.Results Wetlands within the region declined by 8.6% between the two time periods, but by &gt; 75% in regions of high human population density. Bird densities were also highest in these regions, which comprised wetlands subject to high levels of disturbance. The geographical coincidence of high densities and habitat loss and the existence of positive associations between bird density and occurrence meant that birds declined by much more than the average rate of their habitat.Main conclusions Targeting conservation efforts in areas with high drainage would protect a high proportion of the bird populations. Encouraging people to derive income from disturbance to which the birds are tolerant, rather than drainage, is likely to be an effective strategy. Because habitat characteristics are a key driver of abundance–occupancy relationships, we conclude that there is wide‐scale scope to couple abundance–occupancy relationships with remote habitat mapping to efficiently inform conservation planning.

Design Factors and Socioeconomic Variables Associated with Ecological Responses to Fishery Closures in the Western Indian Ocean

We assessed the ability of socioeconomic variables (population size, perceived infringement, and community infrastructure) and design features (closure age and area) to predict ecological indicators of “success” in seventeen coral-reef fishery closures in the Western Indian Ocean. Success was measured as absolute fish biomass and coral cover in closures, and the response ratio of these variables indicating the level of difference relative to control sites outside closures. Fish biomass had a greater and more consistent response to protection than coral cover. Human population density had a strong positive association with the response of fish biomass, which was driven by lower biomass outside marine protected areas (MPAs) in high human population density sites, rather than higher biomass within MPAs. Perceived infringement was negatively associated with the absolute and response ratio of fish biomass. Coral cover was variable, weakly related to closure, and positively related to closure size and human population density. This, and previous regional studies, indicate that physical design features have a modest effect on the response of fish to MPAs, that design features interact with compliance, and that human population density around closures can indirectly influence the effect of MPAs on fish populations.

Importancia de la hidrogeología urbana; ciencia clave para el desarrollo urbano sostenible

Urban expansion as a result of continuous population growth as well as the creation of a large variety of industries and the parallel high human population density require a sufficient supply of clean water. In many cities around the world groundwater is the main source of potable water. In turn, anthropogenic activities discharge large volumes of waste water and industrial effluents. The use of a variety of chemicals and hydrocarbons causes pollution of groundwater supplies and soils. The complex interaction between groundwater flow systems and cities (infrastructure, city process, activities and discharge) requires increasingly complex studies, which is why a new branch of science has emerged under the name of “urban hydrogeology”, considered to be a specialization within the hydrogeological sciences. This paper provides a general vision of urban hydrogeology that allows understanding its conceptual aspects, its scope of application and management. The information presented refers to the interdependence of cities and groundwater use. The paper details the processes and mechanisms studied through this new branch of knowledge as well as their effects in relation to the physical and chemical properties of water quality (pollution processes). Case studies are discussed in order to have a variety of viewpoints on environmental impacts, theoretical development and technological advances developed in order to seek efficient solutions. We highlight guidelines and models for sustainable groundwater management in urban settings that have been developed with the aim

Modelling climate-change-induced shifts in the distribution of the koala

Context The impacts of climate change on the climate envelopes, and hence, distributions of species, are of ongoing concern for biodiversity worldwide. Knowing where climate refuge habitats will occur in the future is essential to conservation planning. The koala (Phascolarctos cinereus) is recognised by the International Union for Conservation of Nature (IUCN) as a species highly vulnerable to climate change. However, the impact of climate change on its distribution is poorly understood. Aims We aimed to predict the likely shifts in the climate envelope of the koala throughout its natural distribution under various climate change scenarios and identify potential future climate refugia. Methods To predict possible future koala climate envelopes we developed bioclimatic models using Maxent, based on a substantial database of locality records and several climate change scenarios. Key results The predicted current koala climate envelope was concentrated in south-east Queensland, eastern New South Wales and eastern Victoria, which generally showed congruency with their current known distribution. Under realistic projected future climate change, with the climate becoming increasingly drier and warmer, the models showed a significant progressive eastward and southward contraction in the koala’s climate envelope limit in Queensland, New South Wales and Victoria. The models also indicated novel potentially suitable climate habitat in Tasmania and south-western Australia. Conclusions Under a future hotter and drier climate, current koala distributions, based on their climate envelope, will likely contract eastwards and southwards to many regions where koala populations are declining due to additional threats of high human population densities and ongoing pressures from habitat loss, dog attacks and vehicle collisions. In arid and semi-arid regions such as the Mulgalands of south-western Queensland, climate change is likely to compound the impacts of habitat loss, resulting in significant contractions in the distribution of this species. Implications Climate change pressures will likely change priorities for allocating conservation efforts for many species. Conservation planning needs to identify areas that will provide climatically suitable habitat for a species in a changing climate. In the case of the koala, inland habitats are likely to become climatically unsuitable, increasing the need to protect and restore the more mesic habitats, which are under threat from urbanisation. National and regional koala conservation policies need to anticipate these changes and synergistic threats. Therefore, a proactive approach to conservation planning is necessary to protect the koala and other species that depend on eucalypt forests.

Trajectories from extinction: where are missing mammals rediscovered?

Aim To determine where mammals that are presumed to be extinct are most likely to be rediscovered, and to test predictions of two hypotheses to explain trajectories of decline in mammals. Range collapse is based on the premise that extinction rates at the edge of species ranges are highest because habitat is suboptimal, so declining species are predicted to survive longer near the centre of their ranges. We predicted that under range collapse, remnant populations are most likely be rediscovered within their former core range. Conversely, if threats usually spread across ranges, declining species will be pushed to the periphery (range eclipse), so rediscoveries are predicted at the edge of the pre-decline range. If so, species would be more likely to be rediscovered in marginal habitat, and at higher elevations than the sites from which they disappeared. Location World-wide. Methods Using data on 67 species of mammals which have been rediscovered, I tested whether species were disproportionately rediscovered in the outer 50% of their former range area or at higher elevations than their last recorded locations, and which species characteristics were associated with rediscovery location and habitat change, using both the phylogenetic generalized least squares method to account for phylogenetic non-independence and linear models of raw species data. Results Species affected by habitat loss were more likely to be rediscovered at the periphery than the centre of their former range, consistent with range eclipse caused by the spread of habitat destruction. High human population pressure predicted which species changed habitat between their previous records and rediscovery. Coastal species experienced higher human population densities, and were more likely to be rediscovered at the periphery of their former ranges, and there was some evidence of an up-slope shift associated with higher human populations at lower elevations. Main conclusion The locations of rediscoveries of species affected by habitat loss were consistent with range eclipse through a mechanism of spreading habitat loss and human population pressure, rather than with range collapse. Searches for mammals that have declined from habitat loss should include range edges and marginal habitat, especially in areas of high human population density.

Questing Ticks in Suburban Forest Are Infected by at Least Six Tick-Borne Pathogens

The role of Ixodes ricinus ticks in the transmission of pathogens of public health importance such as Borrelia burgdorferi s.l. is widely recognized and is suspected in several emerging vector-borne pathogens in Europe. Here, we assess prevalence rates of several endemic and emerging zoonotic pathogens in tick populations in an area of high human population density in France, to contribute to a risk assessment for potential transmission to humans. Pathogen prevalence rates were evaluated by polymerase chain reaction detection and sequencing in questing ticks, individually for adults and in pools of 10 for nymphs. In addition to finding micro-organisms corresponding to symbionts, we found high prevalence rates of B. burgdorferi s.l. (32% of adult females and 10% of nymphs) and low to moderate ones of Anaplasma phagocytophilum (~1%), spotted fever group Rickettsia spp. (~6%), Babesia sp. EU1 (~1%), Bartonella birtlesii (0.1%), and Francisella tularensis (!1%). Our findings extend the knowledge of the geographical distribution of these endemic and emergent pathogens and support the conclusion that ticks are important vectors of pathogenic micro-organisms in suburban forests. Moreover, tick coinfection with multiple pathogens was found to occur frequently, which poses a serious challenge for diagnosis and appropriate treatment. The incrimination of these pathogens in potentially severe pathologies requires widespread surveillance to assess the risk of infection, thereby facilitating diagnosis and treatment, as well as raising local awareness of tick-borne diseases.

Primates in 21st century ecosystems: does primate conservation promote ecosystem conservation?

Contributors to this issue of the American Journal of Primatology were among the participants in an invited symposium at the 2008 Association for Tropical Biology and Conservation meeting in Paramaribo, Suriname. They were asked to assess how essential primates are to tropical ecosystems and, given their research interests, discuss how primate research contributes to the broader understanding about how ecosystems function. This introduction to the issue is divided into three parts: a review of the roles that nonhuman primates play in tropical ecosystems; the implementation of large-scale landscape methods used to identify primate densities; and concerns about the increasingly porous boundaries between humans, nonhuman primates, and pathogens. Although 20th century primate research created a rich database on individual species, including both theoretical and descriptive approaches, the dual effects of high human population densities and widespread habitat destruction should warn us that creative, interdisciplinary and human-related research is needed to solve 21st century problems.

Irrigated Agriculture Is an Important Risk Factor for West Nile Virus Disease in the Hyperendemic Larimer-Boulder-Weld Area of North Central Colorado

This study focused on two West Nile virus (WNV) disease outbreak years, 2003 and 2007, and included a three-county area (Larimer, Boulder, and Weld) in North Central Colorado that is hyperendemic for WNV disease. We used epidemiological data for reported WNV disease cases at the census tract scale to: (1) elucidate whether WNV disease incidence differs between census tracts classified as having high versus lower human population density (based on a threshold value of 580 persons/km2) and (2) determine associations between WNV disease incidence and habitat types suitable as development sites for the larval stage of Culex mosquito vectors. WNV disease incidence was significantly elevated in census tracts with lower human population density, compared with those with high density of human population, in both 2003 (median per census tract of 223 and 143 cases per 100,000 population, respectively) and 2007 (median per census tract of 46 and 19 cases per 100,000 population). This is most likely related, in large part, to greater percentages of coverage in less densely populated census tracts by habitats suitable as development sites for Culex larvae (open water, developed open space, pasture/hay, cultivated crops, woody wetlands, and emergent herbaceous wetlands) and, especially, for the subset of these habitats made up by irrigated agricultural land (pasture/hay and cultivated crops) that presumably serve as major producers of the locally most important vector of WNV to humans: Culex tarsalis. A series of analyses produced significant positive associations between greater coverage of or shorter distance to irrigated agricultural land and elevated WNV disease incidence. As an exercise to produce data with potential to inform spatial implementation schemes for prevention and control measures within the study area, we mapped the spatial patterns, by census tract, of WNV disease incidence in 2003 and 2007 as well as the locations of census tracts that had either low (<25th percentile) or high (>75th percentile) WNV disease incidence in both outbreak years (relative to the incidence for each year). This revealed substantial changes from 2003 to 2007 in the spatial pattern for census tracts within the study area with high WNV disease incidence and suggests a dynamic and evolving scenario of WNV transmission to humans that needs to be taken into account for prevention and control measures to stay current and represent the most effective use of available resources.

A panel of microsatellites to individually identify leopards and its application to leopard monitoring in human dominated landscapes

BackgroundLeopards are the most widely distributed of the large cats, ranging from Africa to the Russian Far East. Because of habitat fragmentation, high human population densities and the inherent adaptability of this species, they now occupy landscapes close to human settlements. As a result, they are the most common species involved in human wildlife conflict in India, necessitating their monitoring. However, their elusive nature makes such monitoring difficult. Recent advances in DNA methods along with non-invasive sampling techniques can be used to monitor populations and individuals across large landscapes including human dominated ones. In this paper, we describe a DNA-based method for leopard individual identification where we used fecal DNA samples to obtain genetic material. Further, we apply our methods to non-invasive samples collected in a human-dominated landscape to estimate the minimum number of leopards in this human-leopard conflict area in Western India.ResultsIn this study, 25 of the 29 tested cross-specific microsatellite markers showed positive amplification in 37 wild-caught leopards. These loci revealed varied levels of polymorphism (four-12 alleles) and heterozygosity (0.05-0.79). Combining data on amplification success (including non-invasive samples) and locus specific polymorphisms, we showed that eight loci provide a sibling probability of identity of 0.0005, suggesting that this panel can be used to discriminate individuals in the wild. When this microsatellite panel was applied to fecal samples collected from a human-dominated landscape, we identified 7 individuals, with a sibling probability of identity of 0.001. Amplification success of field collected scats was up to 72%, and genotype error ranged from 0-7.4%.ConclusionOur results demonstrated that the selected panel of eight microsatellite loci can conclusively identify leopards from various kinds of biological samples. Our methods can be used to monitor leopards over small and large landscapes to assess population trends, as well as could be tested for population assignment in forensic applications.