A reference allelic ladder for Western Capercaillie (Tetrao urogallus) and Black Grouse (Tetrao tetrix) enables linking grouse genetic data across studies

Rapid anthropogenic climate change and progressing habitat degradation are considered top threats to biodiversity. The employment of demanding umbrella species as indicators for ecosystem health is a popular and cost-effective strategy that facilitates continuous monitoring and evaluation within a long-term conservation management scheme. The Western Capercaillie (Tetrao urogallus) and the Black Grouse (Tetrao tetrix) are both considered viable candidates due to their extensive habitat requirements, the possibility for conservative, non-invasive sampling, and their broad popular appeal. Regional population surveys based on genetic data from Short Sequence Repeat (SSR) analysis are being conducted throughout the Palearctic. However, to ensure reliable comparability among laboratories, standardization is required. Here, we report a catalogue of fifty fully characterized reference alleles from twelve SSR loci and the construction of a customizable allelic ladder for genotyping and individualization in Western Capercaillie and Black Grouse. This methodological improvement will help to cost-efficiently generate and collate supraregional data from different grouse surveys and thereby contribute to conservation management. Reference alleles and ladders can be obtained on demand.

Monitoring black grouse Tetrao tetrix in Isère, northern French Alps: cofactors, population trends and potential biases

Wildlife management benefits from studies that verify or improve the reliability of monitoring protocols. In this study in Isère, France, we tested for potential links between the abundance of black grouse (Tetrao tetrix) in lek–count surveys and cofactors (procedural, geographical and meteorological cofactors) between 1989 and 2016. We also examined the effect of omitting or considering the important cofactors on the long–term population trend that can be inferred from lek–count data. Model selections for data at hand highlighted that the abundance of black grouse was mainly linked to procedural cofactors, such as the number of observers, the time of first observation of a displaying male, the day, and the year of the count. Some additional factors relating to the surface of the census sector, temperature, northing, altitude and wind conditions also appeared depending on the spatial or temporal scale of the analysis. The inclusion of the important cofactors in models modulated the estimates of population trends. The results of the larger dataset highlighted a mean increase of +17 % (+5.3 %; +29 %) of the abundance of black grouse from 1997 to 2001, and a mean increase in population of +47 % (+16 %; +87 %) throughout the study period (1989–2016). We discuss the hypothesis of plausible links between this past increase in the number of black grouse and the ecological impact of the winter storm ‘Vivian’. Findings from our study and the ecological phenomena that were concomitant with the observed population trend provide opportunities to strengthen the monitoring and management of black grouse in the Alps.