How Many Wolves (Canis lupus) Fit into Germany? The Role of Assumptions in Predictive Rule-Based Habitat Models for Habitat Generalists

Abstract

Due to legislative protection, many species, including large carnivores, are currently recolonizing Europe. To address the impending human-wildlife conflicts in advance, predictive habitat models can be used to determine potentially suitable habitat and areas likely to be recolonized. As field data are often limited, quantitative rule based models or the extrapolation of results from other studies are often the techniques of choice. Using the wolf (Canis lupus) in Germany as a model for habitat generalists, we developed a habitat model based on the location and extent of twelve existing wolf home ranges in Eastern Germany, current knowledge on wolf biology, different habitat modeling techniques and various input data to analyze ten different input parameter sets and address the following questions: (1) How do a priori assumptions and different input data or habitat modeling techniques affect the abundance and distribution of potentially suitable wolf habitat and the number of wolf packs in Germany? (2) In a synthesis across input parameter sets, what areas are predicted to be most suitable? (3) Are existing wolf pack home ranges in Eastern Germany consistent with current knowledge on wolf biology and habitat relationships? Our results indicate that depending on which assumptions on habitat relationships are applied in the model and which modeling techniques are chosen, the amount of potentially suitable habitat estimated varies greatly. Depending on a priori assumptions, Germany could accommodate between 154 and 1769 wolf packs. The locations of the existing wolf pack home ranges in Eastern Germany indicate that wolves are able to adapt to areas densely populated by humans, but are limited to areas with low road densities. Our analysis suggests that predictive habitat maps in general, should be interpreted with caution and illustrates the risk for habitat modelers to concentrate on only one selection of habitat factors or modeling technique.

Sedentary but not dispersing wolvesCanis lupusrecolonizing western Poland (2001–2016) conform to the predictions of a habitat suitability model

“…Consequently, during the construction of a HSM for wolves it is essential to distinguish between predictors of areas with just a general presence of the species, including floaters, and the permanent range of the species, where they can establish territories (Marucco & McIntire, ). Models based on observations of solitary wolves wandering in search of mates and free territories, especially if such data included, for example, media reports, may provide inconclusive results (Fechter & Storch, ). Also Cianfrani et al.…”

“…Across their geographic range, wolves inhabit different environments: tundra, boreal and temperate forests, steppes and semi‐deserts, and habitats transformed by humans to varying degrees (Mech & Boitani, ). Therefore, the predictive power of HSMs for wolves has been hotly debated (Fechter & Storch, ; Mech, ,b; Mladenoff, Clayton, Sickley, & Wydeven, ). However, while some authors doubt the predictive power of HSMs for wolves (Cayuela, ; Mech, ), others have revealed environmental factors that support or hamper wolf occurrence (Kaartinen, Kojola, & Colpaert, ; Llaneza, López‐Bao, & Sazatornil, ; Thiel, ; Thurber, Peterson, Drummer, & Thomasma, ; Wydeven et al., ).…”

Where can wolves live and how can we live with them?

“…Several qualifications are necessary, however, to properly understand the European situation and how that relates to wolf recolonization of the 48 contiguous United States (Mech, 2016).First, the high human densities in Europe are mostly in cities, so any wolf conflict is borne by the sparse populations in the countryside.Most European wolves inhabit Spain, Italy and such countries as Greece, Romania, Bulgaria, whereas wolves have only recently begun to recolonize the wealthier nations such as Germany (Fechter and Storch, 2014).Thus the average European human density as cited by Chapron et al (2014) is not a suitable metric by which to gauge wolf compatibility with humans.Second, several of the countries supporting the highest number of wolves attempt to control them by hunting (Boitani, 2003), including Sweden, which is in open violation (Castle, 2015) of the European Union's Habitat Directive (Epstein et al, 2016).Third, in every country, whether wolves are legally protected or not, there is a high rate of human taking by vehicle strikes, livestock depredation control and poaching (Boitani, 2003;Liberg et al, 2012;Ciucci, 2015;Von Rushkowski, 2016).Even in the European Union, wolf protection is weakly enforced (Sazatornil et al, 2016).…”

“…If the only place wolves can live with minimal conflict with humans is in wild lands, where are there sufficient wild lands that are still wolffree?Wild lands can be considered any extensive area undeveloped and relatively uninhabited by humans.There is necessarily some variation and subjectivity in considering where such areas suitable for wolves exist because the region surrounding many suitable wild lands would sustain conflict from wolves dispersing from them.The degree of conflict and the tolerance of local citizens will vary by locale.In Europe, that will depend considerably on the culture of each individual nation.How many of the 10,000 wolves Germany might be capable of supporting (Fechter and Storch, 2014) will it tolerate? In the U.S., estimates are that part of the southern Rocky Mountains could sustain a population of more than 1000 wolves (Carroll et al, 2003).In the Central U.S., a habitat-suitability study suggested that about 42% of the region (primarily Texas north through North Dakota) was suitable for wolves (Smith et al, 2015).However, those studies did not explicitly consider such negative factors as potential for depredation on livestock and other conflicts with humans, as well as local public attitudes toward wolves.The importance of these factors can be seen in the latter study's conclusion that substantial parts of North and South Dakota were deemed suitable even though wolves have been unable to recolonize them from Minnesota for decades because of poaching (Licht and Fritts, 1994).…”

Wolf population genetics inEurope: a systematic review, meta‐analysis and suggestions for conservation and management

“…In western Poland the loss of any individual has been thought to influence the survival of the pack or interrupt colonization of adjacent areas (Jędrzejewski et al., ). Species distribution models have shown that human factors, especially road density and culling might limit the further spread of the species in Germany (Fechter & Storch, ) (Table ). The connectivity of the Central European Lowland population with neighbouring populations is still weak and currently restricted to occasional gene flow from the Baltic population (Kaczensky et al., ).…”