Canopy cover and understory composition determine abundance of Vaccinium myrtillus L., a key plant for capercaillie (Tetrao urogallus), in subalpine forests in the Pyrenees

Abstract

Background: The dwarf shrub Vaccinium myrtillus -with high cover, height, and fruit production -benefits capercaillie (Tetrao urogallus). Aims: Our aim was to quantify landscape (e.g. elevation, geographic location, and precipitation), site (e.g. overstorey cover and stoniness) and very fine scale factors (e.g. spatial associations in the understorey) that affect cover, height, and fruit production of V. myrtillus in subalpine forests in thePyrenees, with understorey usually dominated by Rhododendron ferrugineum. Methods: We sampled 155 plots (0.5 m × 5 m) in six sites. For each plot, in the understorey layer, we assessed species cover, height for R. ferrugineum and V. myrtillus, number of total fruits in V. myrtillus, and spatial associations among V. myrtillus and the remaining cover types. Results: Overstorey cover negatively influenced V. myrtillus cover, its height, and particularly, the number of fruits, which was also negatively influenced by R. ferrugineum cover. Associations between R. ferrugineum and V. myrtillus were site dependent, while V. myrtillus showed mostly positive associations with grasses and mosses. Conclusions: Reducing overstorey and R. ferrugineum cover has the strongest positive effect on increasing V. myrtillus fruit production, but with additional positive effects on V. myrtillus cover and height. Increases in grass and moss coverage could favour V. myrtillus.

Bird community response in mountain pine forests of the Pyrenees managed under a shelterwood system

“…However, we cannot rule out that increased light availability after regeneration cuts could also enhance shrub species richness, which may also contribute to increase understory nesting and foraging bird abundance in mountain pine forests (e.g. blueberries; Montaner et al 2016). In this sense, model explanatory power was the lowest for both guilds (R 2 ≤ 0.11).…”

Altitudinal Shift of Tetrao urogallus in an Alpine Natura 2000 Site: Implications for Habitat Restoration

“…Accordingly, Graf et al [11] recorded capercaillie more often on gentle slopes, mountain ridges, or upper slopes, rather than on very steep topography, toe slopes, or valley bottoms. In both years, the cover of the herbaceous layer was positively related to capercaillie presence, and this might be due to the fact that grass cover can favor V. myrtillus [44]. However, the herbaceous layer height had a negative influence, as this may have negatively influenced berries and the type and amount of invertebrates, in turn impacting on food availability for the chicks [45].…”