Grazing networks provide useful functional connectivity for plants in fragmented systems

Abstract

Question To what extent does the movement of animals between fragmented habitat patches provide functional connectivity via endozoochorous seed dispersal? Location The Stockholm archipelago, Sweden. Methods We followed all movements of livestock between islands during one grazing season. After each movement, manure was collected and its seed content assessed through seedling emergence. Seedling data were then compared to vegetation surveys from the grazed islands with regard to functional traits. Results Light‐ and nitrogen‐demanding locally abundant species, and those with relatively small and persistent seeds were more likely to be moved between islands. For quantitative traits, only a subset of the available trait ranges were dispersed, with extreme values left behind. Species apparently specialized to other means of dispersal emerged from the manure samples. Neither dispersed traits nor seed density changed with timing of movement, but seed richness and diversity both increased throughout the season. The subsets of endozoochorously‐dispersed species in the established vegetation were more similar than non‐dispersed subsets between islands linked by livestock. Conclusions Grazing networks contribute to the connectivity of the core species in the system, and could provide useful tools for grassland management in fragmented landscapes.

How do freshwater organisms cross the “dry ocean”? A review on passive dispersal and colonization processes with a special focus on temporary ponds

“…As an example, the seasonal movements of livestock (transhumance) traditionally occurring since centuries in many Mediterranean countries may have played an important role in the dispersal of aquatic organism in this area even though few existing studies on this topic are dealing with terrestrial plants and animals (e.g. Fischer et al, 1996;Auffret et al, 2012). Moreover, pastoral activity all around the world is not the only human-driven activity which may enhance organism dispersal.…”

The geography of human‐mediated dispersal

“…At the landscape scale, seeds can be dispersed during the organized movement between pastures either guided along paths or transported longer distances ( Fig. 1d; Wessels et al, 2008;Hogan & Phillips, 2011;Auffret et al, 2012). The direction of such movement and transportation will depend on land ownership or membership of local conservation schemes.…”

Disturbance by large herbivores alters the relative importance of the ecological processes that influence the assembly pattern in heterogeneous meta‐communities

“…In addition, large herbivores may act as agents of long‐distance dispersal via epi‐ and endozoochory, which promote the interchange of propagules among local communities (Auffret et al. ). Moreover, several studies have reported that an increase in the disturbance caused by large herbivores has driven biotic homogenization by causing a loss of palatable habitat specialists and the expansion of browse‐tolerant generalists (McKinney and Lockwood ; Rooney et al.…”