Range loss of a threatened grouse species is related to the relative abundance of a mesopredator

Abstract

Citation: K€ ammerle, J.-L., J. Coppes, S. Ciuti, R. Suchant, and I. Storch. 2017. Range loss of a threatened grouse species is related to the relative abundance of a mesopredator. Ecosphere 8(9):e01934. 10. 1002/ecs2.1934 Abstract. Mammalian generalist mesopredators can reach high densities in forest-farmland mosaic landscapes in the absence of top-down control. The abundance of generalist mesopredators is a potentially limiting factor for prey populations, especially ground breeding birds such as grouse. High mesopredator abundance has been associated with reduced reproductive success in grouse. There is little evidence, however, on how variation in mesopredator abundance affects grouse population trends while considering other environmental covariates. We make use of range maps spanning two decades (1993-2013) of a locally threatened capercaillie (Tetrao urogallus) population in the Black Forest, Germany, to assess whether range loss of grouse in forest-farmland mosaic landscapes can be explained by a gradient in red fox abundance, while accounting for other potential determinants of grouse range loss. We show that capercaillie range persistence was favored by increasing snow cover, decreasing index of red fox abundance, slightly increasing index for soil quality, and increasing population connectivity. Red fox abundance had the largest relative impact in areas already facing an elevated capercaillie extinction risk due to unsuitable site conditions, dense forests, or lack of connectivity, but the negative effect was compensated under otherwise optimal conditions. This indicates that the relative importance of predator abundance for prey population dynamics is mediated by environmental attributes, emphasizing the threat to remnant populations but also indicating potential for species conservation.

Restricted‐area culls and red fox abundance: Are effects a matter of time and place?

“…Home‐range sizes obtained through VHF telemetry in parts of the study area (Kaphegyi, ) suggest low to intermediate red fox density (below five individuals km −2 ; Šálek, Drahníková, & Tkadlec, ). Management of red fox populations is incentivized in the study area, because red foxes are considered important predators of capercaillie ( Tetrao urogallus ), a locally threatened grouse species (Kämmerle et al, ). Grouse are ground nesting birds and thus vulnerable to predation of eggs and chicks as well as adult birds (Storch, ).…”

“…The area is characterized by a land use mosaic dominated by mixed montane forests (approximately two-thirds forest cover, Braunisch & Suchant, 2007), fragmented by settlements, single farms, and agricultural land cover types (primarily livestock pastures; Figure 1). For more information on the study area, see Kämmerle, Coppes, Ciuti, Suchant, and Storch (2017) and Kämmerle, Corlatti, Harms, and Storch (2018). Red foxes occur in all parts of the study area and their relative abundance varies in relation to landscape configuration (Güthlin et al, 2013).…”

The importance of individual heterogeneity for interpreting faecal glucocorticoid metabolite levels in wildlife studies

“…The Black Forest capercaillie population is isolated from other populations in central Europe (Segelbacher et al., ) and highly fragmented (Braunisch, Segelbacher, & Hirzel, ; Coppes et al., ). Population size and distribution have been continuously decreasing over the last 30 years (Coppes et al., ), with the cause considered to be multifactorial, including habitat deterioration (Suchant & Braunisch, ), habitat fragmentation (Braunisch et al., ), predator abundance (Kämmerle et al., ), disturbance through human recreation (Coppes et al., ) as well as climate change (Braunisch et al., ; Huntley, Green, Collingham, & Willis, ).…”

“…In our study, we collected faecal samples across the entire geographical range of an endangered central European capercaillie population. We chose capercaillie as an ideal study model because FCM are calibrated (Thiel et al., ), they occur in various landscapes (Klaus et al., ) and they respond to various stressors such as predation (Kämmerle, Coppes, Ciuti, Suchant, & Storch, ), climate change (Braunisch et al., ), habitat degradation (Suchant & Braunisch, ) and human disturbance (Coppes et al., ) while being threatened throughout their central European range (Storch, ). By combining FCM measurements in three consecutive winters with genetic (i.e.…”

Predation, predator control and grouse populations: a review

“…2016, Lyly et al 2016, Kämmerle et al 2017, while one study found such a relationship only for one of several grouse species (Tornberg et al 2013). In Sweden, Lindström et al (1994) monitored red foxes and three grouse species at several spatial scales during a sarcoptic mange outbreak and concluded that predation by foxes is limiting grouse abundance.…”