Tiger Habitat Suitability model

Heterogeneity of agricultural landscapes is supposed to be of significant importance for species diversity in agroecosystems. Thus it is necessary to account for structural aspects of landscapes in land management decision processes. Spatial ...

Illegal hunting of rhinoceros in East Africa was widespread in the late 1970s. Today, rhinoceros numbers remain perilously low. The Eastern black rhinoceros (Diceros bicornis michaeli) is restricted to protected areas within Kenya and Tanzania and the few protected areas in Kenya where rhinoceroses are found are reaching carrying capacity. The Serengeti-Mara Ecosystem represents the best potential site for population

This study describes the spatial distribution of young-of-the-year sole based on autumnal beam trawl surveys conducted in the Bay of Biscay (France) during a 15-y period. Previous studies showed that habitat suitability for juvenile sole varies according to physical factors such as bathymetry, sediment structure and river plume influence. These factors, which are known exhaustively for the entire Bay of

Carnivores are often particularly sensitive to landscape fragmentation. Ecological corridors may help to connect local populations, ensuring gene flow and retaining viable meta-populations. We aimed to establish habitat suitability models for two large carnivores in Poland, the grey wolf Canis lupus Linnaeus, 1758 and the Eurasian lynx Lynx lynx Linnaeus, 1758, based on ecological niche factor analysis (ENFA). Secondly, we calculated least cost paths (LCPs) based on cost values obtained from ENFA. Thirdly, we determined structures that might act as barriers, thus diminishing the value of the corridor unless appropriate conservation measures are taken. We compared some of the results with actual dispersal data of four lynx in eastern Poland. Results indicate that both species are highly marginalised. Less habitat that is currently available in Poland is suitable for lynx than for wolves. We determined a total of 76 LCPs. Comparison of these theoretical corridors with actual dispersal routes suggests that the traits of calculated LCPs are mostly within the range of those of real routes. We highlight a variety of features that might act as barriers, such as major roads (including planned highways), urbanized areas, and large un-forested areas. We give suggestions where concerted conservation efforts (eg wildlife passages) might be particularly well-directed.

To facilitate decision support in freshwater ecosystem protection and restoration management, habitat suitability models can be very valuable. Data driven methods such as artificial neural networks (ANNs) are particularly useful in this context, seen their time-efficient development and relatively high reliability. However, specialized and technical literature on neural network modelling offers a variety of model development criteria to select model architecture, training procedure, etc. This may lead to confusion among ecosystem modellers and managers regarding the optimal training and validation methodology. This paper focuses on the analysis of ANN development and application for predicting macroinvertebrate communities, a species group commonly used in freshwater assessment worldwide. This review reflects on the different aspects regarding model development and application based on a selection of 26 papers reporting the use of ANN models for the prediction of macroinvertebrates. This analysis revealed that the applied model training and validation methodologies can often be improved and moreover crucial steps in the modelling process are often poorly documented. Therefore, suggestions to improve model development, assessment and application in ecological river management are presented. In particular, data pre-processing determines to a high extent the reliability of the induced models and their predictive relevance. This also counts for the validation criteria, that need to be better tuned to the practical simulation requirements. Moreover, the use of sensitivity methods can help to extract knowledge on the habitat preference of species and allow peer-review by ecological experts. The selection of relevant input variables remains a critical challenge as well. Model coupling is a missing crucial step to link human activities, hydrology, physical habitat conditions, water quality and ecosystem status. This last aspect is probably the most valuable aspect to enable decision support in water management based on ANN models.

1After an absence of almost 100 years, the Eurasian lynx Lynx lynx is slowly recovering in Germany along the German–Czech border. Additionally, many reintroduction schemes have been discussed, albeit controversially, for various locations. We present a habitat suitability model for lynx in Germany as a basis for further management and conservation efforts aimed at recolonization and population development.2We developed a statistical habitat model using logistic regression to quantify the factors that describe lynx home ranges in a fragmented landscape. As no data were available for lynx distribution in Germany, we used data from the Swiss Jura Mountains for model development and validated the habitat model with telemetry data from the Czech Republic and Slovenia. We derived several variables describing land use and fragmentation, also introducing variables that described the connectivity of forested and non-forested semi-natural areas on a larger scale than the map resolution.3We obtained a model with only one significant variable that described the connectivity of forested and non-forested semi-natural areas on a scale of about 80 km2. This result is biologically meaningful, reflecting the absence of intensive human land use on the scale of an average female lynx home range. Model testing at a cut-off level of P > 0·5 correctly classified more than 80% of the Czech and Slovenian telemetry location data of resident lynx. Application of the model to Germany showed that the most suitable habitats for lynx were large-forested low mountain ranges and the large forests in east Germany.4Our approach illustrates how information on habitat fragmentation on a large scale can be linked with local data to the potential benefit of lynx conservation in central Europe. Spatially explicit models like ours can form the basis for further assessing the population viability of species of conservation concern in suitable patches.After an absence of almost 100 years, the Eurasian lynx Lynx lynx is slowly recovering in Germany along the German–Czech border. Additionally, many reintroduction schemes have been discussed, albeit controversially, for various locations. We present a habitat suitability model for lynx in Germany as a basis for further management and conservation efforts aimed at recolonization and population development.We developed a statistical habitat model using logistic regression to quantify the factors that describe lynx home ranges in a fragmented landscape. As no data were available for lynx distribution in Germany, we used data from the Swiss Jura Mountains for model development and validated the habitat model with telemetry data from the Czech Republic and Slovenia. We derived several variables describing land use and fragmentation, also introducing variables that described the connectivity of forested and non-forested semi-natural areas on a larger scale than the map resolution.We obtained a model with only one significant variable that described the connectivity of forested and non-forested semi-natural areas on a scale of about 80 km2. This result is biologically meaningful, reflecting the absence of intensive human land use on the scale of an average female lynx home range. Model testing at a cut-off level of P > 0·5 correctly classified more than 80% of the Czech and Slovenian telemetry location data of resident lynx. Application of the model to Germany showed that the most suitable habitats for lynx were large-forested low mountain ranges and the large forests in east Germany.Our approach illustrates how information on habitat fragmentation on a large scale can be linked with local data to the potential benefit of lynx conservation in central Europe. Spatially explicit models like ours can form the basis for further assessing the population viability of species of conservation concern in suitable patches.

Abstract The knowledge of the areas inhabited by a species within its distribution range and the connections among patches are critical pieces of information for successful conservation actions. The internal structure of the extent of occurrence (EO) of a species is almost ...

The introduction of alien species to new environments is one of the main threats to the conservation of biodiversity. One particularly problematic example is that of wild ungulates which are increasingly being established in regions outside their natural distribution range due to human hunting interests. Unfortunately, we know little of the effects these large herbivores may have on the host ecosystems. This study deals with a first comparative analysis of the habitat requirements of two ungulate species that may be facing competition for resources in the south of Europe: the native Iberian ibex (Capra pyrenaica) and the exotic aoudad (Ammotragus lervia). The aoudad is a North African caprid introduced in 1970 as a game species in south-eastern Spain. It has adapted well, and populations have been freely expanding since then. Ecological Niche Factor Analysis is used to describe the realized niche of both species where their distribution ranges merge. Both species occupy marginal areas of rugged terrain in the region. Marginality is higher for the Iberian ibex, which also presents a higher tolerance of secondary environmental gradients than the aoudad. Highly suitable areas for each species are secondarily suitable for the other. Reclassified and cross-tabulated habitat suitability maps showing the areas of potential spatial coexistence and differences in ecological traits between both species are provided. The results obtained do not allow inferring resource competition between these species. However, current aoudad expansion could result in it invading the favoured habitats of the ibex. Inadequate hunting policy and monitoring, and increasing climatic resemblance of the study region to the native aoudad areas, due to a strong desertification process, are facilitating a high rate of expansion. We strongly recommend to eradicate or, at least, monitor these exotic populations, and promote active conservation practices, if one wants to preserve the unique natural resources present in this European region.

This study attempts to model the probability of occurrence of some characteristic macro-invertebrate species of the Baltic Sea from different functional groups (i.e. grazers, deposit and suspension feeders, and predators) in response to major environmental forcing factors (salinity, water depth and seabed substrate type). Analyses were based on the inventory data set compiled by revising the data on macrobenthic species for over 12,000 sampling events in the Baltic Sea. In addition, data on environmental variables are retrieved from the results of modelling and large-scale mapping efforts. A simple logistic regression based modelling technique was applied and the candidate model with highest discriminatory power was selected for habitat suitability mapping. Habitat suitability models allowed to satisfactorily predict the potential distribution of macrofaunal species based solely on modelled salinity, bathymetry and rough sediment class information. Our results indicated that salinity, depth and substrate type are all important in determining the distribution of most characteristic macrobenthic species on the large-scale of the whole Baltic Sea. The present exercise is only a first step. Implementation of other variables (e.g. characterizing oxygen and temperature fluctuations, total organic content, and nutrient supply) would obviously increase the model applicability. Information on the ecological potential of habitat suitability can serve as the utmost important basis for scientifically sound marine spatial planning.

Abstract: The lack of comprehensive sighting data sets precludes the application of standard habitat suitability modeling approaches to predict distributions of the majority of marine mammal species on very large scales. As an alternative, we developed an ecological niche model to map global distributions of 115 cetacean and pinniped species living in the marine environment using more readily available expert knowledge about habitat usage. We started by assigning each species to broad-scale niche categories with respect to depth, sea- ...

The endangered Cantabrian capercaillie (Tetrao urogallus cantabricus) lives at the southern edge of tetraonids’ distribution range, in entirely deciduous forests. Its conservation planning has been always lek-centred. There is very little information about the specific habitat requirements of hens and broods, even though reproductive success appears to be a limiting factor. We analysed summer surveys from 1997 to 2004, carried out to estimate the reproductive success of the population. We compared the habitat characteristics at different spatial scales of hens with broods, broodless hens, and cocks in summer, with the better known spring habitat in display areas. Summer habitat showed higher proportion of open areas and was associated with more rugged zones at moderate spatial scales (78 ha) than spring habitat at display areas. Cocks and hens showed summer habitat partitioning; hens were associated with higher proportions of open and shrubby habitats. Furthermore, broodless hens preferred areas with higher slope variability than the display and summer areas preferred by cocks. These differences may reflect the sexual dimorphism of the species in reproductive role, energetic demands and conspicuousness. At larger spatial scales a previously developed habitat suitability model performed well to predict good brood-rearing areas. Hens with broods were located in the best-preserved areas in the range, mainly characterized by higher proportion of forest cover at a large (50 km2) scale. We suggest that these characteristics indicate refuge habitats where Cantabrian capercaillie can still breed successfully.

Predictive distribution models generally use data from multiple individuals each associated with a unique observation location, coupled with environmental parameters, to define the overall suitable area where the species could occur. Whether the use of multiple locations from few individuals is similarly efficient to model species distribution is not yet known. If so, the method could bring valuable inputs to identify priority conservation areas for rare or elusive species, especially those large vertebrates tracked with telemetry. Satellite tracking of long-distance migrants often produces numerous locations of surveyed individuals across their wintering ranges. We examined such wintering tracks to test if the wintering locations obtained from few tracked individuals could be useful to model the full species wintering range, using habitat suitability models. We aimed at predicting the wintering distribution of West European Black Storks Ciconia nigra. We used tracks of 9 storks, retaining one location per winter day per individual for a total of 972 different locations. Combined with bioclimatic and land cover data in habitat suitability modelling within an ensemble forecast framework, we obtained a probabilistic distribution which largely matched the previously reported wintering range of the species in western and central Africa. Using tracks of the six individuals with more than 100 locations each, we obtained a distribution range closely matching the nine-bird range. A range similar to the nine-bird range could be predicted by models using data from less numerous individuals and by considering a lower threshold value. Habitat suitability models using wintering record locations of satellite-tracked migrant birds can therefore help to get a better picture of the wintering distribution range, and hence provide more accurate information for conservation planning on African wintering grounds.

Application of remote sensing and Geographic Information System (GIS) as a tool has assumed an immense significance in habitat suitability modelling for various wildlife species and now a days these are widely used in conservation biology and wildlife management.This paper evaluates habitat suitability for tigers (Panthera tigris tigris) in Chandoli National Park, India. This research provides information about potential areas that can be declared as Tiger Reserve, a federal designation of protection. Habitat evaluation was completed in the Chandoli National Park (17° 04′ 00″ N to 17° 19′ 54″ N and 73° 40′ 43″ E to 73° 53′ 09″ E) using habitat suitability index (HSI). Remotely sensed data of satellite IRS-P6, LISS-III of 25th February 2005 was procured from National Remote Sensing Agency, India. The satellite imagery data was digitally processed and collateral data were generated from topographic maps in a GIS framework. Various layers of different variables such as landuse land cover, forest density, measures of proximity to disturbances and water resources and a digital terrain model were created based on ground truthing. These layers, GPS location of animal's presence and “binomial multiple logistic regression (BMLR)” techniques were integrated in a GIS environment for the HSI modelling.Results indicate that approximately 160.48 km2 (55%) of the forest of Chandoli National Park is highly suitable for herbivores population, and 176.52 km2 (50%) of the Park is suitable for tigers. Therefore, this study concludes that forest areas within the Chandoli National Park are appropriate for consideration as Tiger Reserve.Furthermore, the identification and mapping of wildlife corridors and other forest patches lying in between neighboring protected area like Koyana sanctuary, suggests that these region of Sahyadri range of Western Ghats should be included into the proposed Tiger Reserve. This will be a benefit for tigers, as tigers require larger and least disturbed forest habitats for establishing and maintaining their high-density population. Fortunately, in May 2008 the Government of India declared Chandoli NP as tiger reserve. Thus declaration of Chandoli National Park as a Tiger Reserve reflects that the habitat suitability model developed by us for tiger was not only statistically sound but also has potential to be considered while taking any decision regarding wildlife habitat management.