Functional traits of seeds dispersed through endozoochory by native forest ungulates

Abstract

Aims: Zoochory is a prominent dispersal process in a wide range of plant species.However, the extent to which the trait composition of dispersed seed assemblages differs from the regional assemblage remains untested, as does the extent to which sympatric native herbivores disperse traits non-randomly.Location: Lorris and Montargis forests, central France. Methods:We compared the taxonomic and functional composition of seed assemblages dispersed by three wild ungulates to the characteristics of the regional flora in an agro-forested landscape. We collected roe deer (Capreolus capreolus), red deer (Cervus elaphus) and wild boar (Sus scrofa) faeces in two forests, and subjected the samples to germination under controlled conditions. We first examined how different vectors influence the composition of the dispersed plant assemblages by comparing abundance and species richness of the seedlings emerging from the faeces of the three ungulates. We then compared the functional characteristics of the dispersed pool with those of the regional flora in a multivariate functional space built from 20 relevant plant traits.Results: A total of 754 seedlings and 46 plant species germinated from 300 faeces samples, with higher plant species richness and abundance for red deer faeces. All three ungulates widely use forest habitat, but the proportion of non-forest plants was higher in red deer and wild boar faeces than in the regional species pool. Traits such as seed shape, seed size or seed bank longevity affected dispersal probability, but their effects were overshadowed by habitat effects.Conclusions: Endozoochory acts as an indirect functional filter, filtering species according to the vectors' feeding habitat. This could affect the composition of forest plant communities by allowing plants from open habitats to colonize forested areas.

Can plant traits predict seed dispersal probability via red deer guts, fur, and hooves?

“…In any case, this result is aligned with findings elsewhere that forest plant species are dispersed less between forest fragments, than are species from the arable landscape matrix dispersed into forest fragments (Panter & Dolman, 2012;Picard et al, 2016).…”

“…This overweight of Juncus has not been found in other studies (e.g., Couvreur et al (2005) Graae, 2002;Picard et al, 2016). The most abundant species for these two modes of epizoochory were J. effusus, with 76% of all seeds in the fur, and 49% of all seed from the hooves.…”

“…They may also transfer diaspores to unoccupied suitable habitat and promote local establishment by soil disturbance (Iravani et al, 2011;von Oheimb, Schmidt, Kriebitzsch, & Ellenberg, 2005;Picard & Baltzinger, 2012;Picard, Chevalier, Barrier, Boscardin, & Baltzinger, 2016). They may also transfer diaspores to unoccupied suitable habitat and promote local establishment by soil disturbance (Iravani et al, 2011;von Oheimb, Schmidt, Kriebitzsch, & Ellenberg, 2005;Picard & Baltzinger, 2012;Picard, Chevalier, Barrier, Boscardin, & Baltzinger, 2016).…”

“…| 9769 PETERSEN aNd BRUUN species. They may also transfer diaspores to unoccupied suitable habitat and promote local establishment by soil disturbance (Iravani et al, 2011;von Oheimb, Schmidt, Kriebitzsch, & Ellenberg, 2005;Picard & Baltzinger, 2012;Picard, Chevalier, Barrier, Boscardin, & Baltzinger, 2016). This may be especially important in fragmented landscapes (Graae, 2002;Panter & Dolman, 2012).…”

The role of ungulates in nowadays temperate forests. A response to Fløjgaard et al. (DOI:10.1111/gcb.14029)

“…While Fløjgaard et al. () consider that the landscape context may bias our results, recent independent (Jaroszewicz, Pirożnikow, & Sondej, ; Picard, Chevalier, Barrier, Boscardin, & Baltzinger, ), but also older studies (von Oheimb, Schmidt, Kriebitzsch, & Ellenberg, ; Schmidt, Sommer, Kriebitzsch, Ellenberg, & von Oheimb, ) on seed dispersal by wild ungulates suggest that there is no overall effect of the landscape matrix on the traits of the plants dispersed by our three model ungulates; these animals disperse preferentially plants typical of open habitats even in forest‐dominated landscape matrices.

Characteristics of forest stands of the 82 plots used in Boulanger et al., . (<1600: before 1600) Dominant tree species Stand origin Stand structure Forest continuity (earliest known existing forest; years) Land‐use change since 1900 Plantation Natural regeneration Even‐aged Uneven‐aged Coppice with standards Range Median Yes No Uncertain Oak1262403[<1600; 1874]16190270Douglas fir50500[<1600; 1969]1790500Norway spruce82910[<1600; 1969]1914622Beech1141500[<1600; 1852]17660150Pine1041400[1700; 1954]1874527

…”