Edge effect and influence of economic growth on Eurasian lynx mortality in the Białowieża Primeval Forest, Poland

Rafał Kowalczyk,Marcin Górny,Krzysztof Schmidt

doi:10.1007/s13364-014-0203-z

Rafał Kowalczyk, Marcin Górny + Show 1 more

Open Access

https://doi.org/10.1007/s13364-014-0203-z

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Abstract

Eurasian lynx is one of most widely distributed felid species. However, populations in central Europe are strongly fragmented and limited to forest areas, which may influence their sustainability and gene flow. We studied the edge effect on mortality of a highly isolated population of Eurasian lynx in the Bialowieza Primeval Forest (NE Poland) during the 20-year period (1991–2011) of high economic development in Poland. Based on radio-tracking data collected in 1991–1996 (low gross national income per capita; low GNI PC) and 2004–2011 (high GNI PC) and recorded mortality cases, we analysed annual rates and causes of mortality and spatial distribution of death sites relative to the distance from the forest edge. We found significantly higher mortality of lynx during the low GNI PC phase of the economic growth than during high GNI PC (33 and 16 %, respectively). While anthropogenic factors played a dominant role in lynx mortality during low GNI PC, natural factors prevailed afterwards. We found a significantly higher proportion of lynx deaths than expected in the edge and outer zone than in the core of the Bialowieza Forest. Both areas differ significantly in the proportions of mortality causes with anthropogenic factors being the main source of mortality in the outer zone. Our results indicate that the decline of lynx mortality in Poland could be related to the improving of the economic situation in the country after the collapse of communism and reduced significance of anthropogenic factors (mainly poaching). Additionally, the outskirts of the forest may function as population sinks, which may reduce the dispersal of lynx and gene flow between populations inhabiting different forest patches.

Highlights

Large carnivores live in low densities and roam over long distances; vast areas are essential for long-term viability of their populations
Annual lynx mortality estimated on the basis of radiotracking data was higher during the low gross national income per capita (GNI PC) period (33 %) (1991–1996) than that during the high GNI PC (16 %) (2004–2011) (G-test; G = 6.02, df = 1, p < 0.02) (Table 1)
There was a reversed pattern of cause-specific mortality rates recorded in the two periods, with anthropogenic factors playing a dominating role during the first period and Number of tracked lynx

Summary

Introduction

Large carnivores live in low densities and roam over long distances; vast areas are essential for long-term viability of their populations. The risk of mortality increases when carnivores roam beyond protected areas or on the edges of their distribution range (Woodroffe and Ginsberg 1998). Such outer areas may act as population sinks (Delibes et al 2001; Bunnefeld et al 2006). Recent studies on lynx genetic diversity and differentiation have suggested that closely situated but isolated populations are poorly connected through contemporary gene flow (Schmidt et al 2009, 2011; Ratkiewicz et al 2012), indicating the possible effect of habitat fragmentation on the effectiveness of lynx dispersal. Studies in Scandinavia have shown that human-induced factors (harvest, poaching, vehicle collisions) are the chief mortality causes in this species

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