Epizoochory in a hedgerow habitat: seasonal variation and selective diaspore adhesion

Abstract

Epizoochory has been less studied than other seed dispersal mechanisms, such as endozoochory, and generally only a small percentage of plant species show adaptations to this strategy. Nevertheless, epizoochorous seed dispersal can affect an appreciable number of herb species in forests and man‐made habitats. Also, few studies have dealt with temporal variation in epizoochory. In this paper, medium‐long distance epizoochory is analyzed in a hedgerow habitat for the first time, using a domestic dog in an area in northwest Spain. Special attention is paid to seasonal variation and differential traits of plant taxa involved. Approximately 30 % of available herb taxa were found attached to hair. The intermonthly difference in the frequency of the taxa involved in epizoochory was significant, and the overall peak was reached in June–October linked with diaspore ripening phenology. Ninety‐three percent of the plant taxa adhered to hair had diaspores with traits facilitating epizoochory (hooks, spines, awns, rigid hairs), in comparison with 17 % for available plant taxa not adhered to hair. The taxa involved in epizoochory had larger diaspores than the rest of the available taxa, but ranged considerably in size. Numerous hooks covered the largest, heaviest diaspores, and allowed them to attach to hair. There was no significant difference in mean plant height between taxa involved in epizoochory and the rest of the available taxa. The difference in life span between taxa involved in epizoochory and the rest of available taxa was not significant, most of them being perennials in both cases. Seventy‐three percent of all the available plant taxa were potential forest plants typically found in edges and gaps, and 64 % of the plant taxa involved in epizoochory were these kinds of potential forest plants. High or medium involuntary positive selection by the dog of diaspores of Taraxacum gr. officinale, Galium aparine, Geum urbanum, and Agrimonia eupatoria was observed. In conclusion, epizoochorous dispersal can be quantitatively and functionally important in hedgerow habitats during summer‐autumn, affecting mainly herb taxa with specialized diaspores.

Nest-site selection and nest design of Iberian bullfinches Pyrrhula pyrrhula iberiae in northwestern Spain

“…Only on hedgerow edges, April–August vegetation samplings revealed a total of 44 herb taxa in the study area, mostly eudicot, potential forest species. 47 All European finches, including bullfinches, use leaves to construct the outer nest and internal cup, but in a low proportion, 14 in agreement with the present study.…”

“…The area is located in a transition zone to the Eurosiberian region, south of the Cantabrian mountain range, in an extensive hedgerow network of great conservation value for flora and fauna. 45–47 About thirty species of broadleaved, chiefly deciduous shrubs, trees, and climbers, are found in the hedgerows. The landscape and hedgerow density and structure are very similar throughout the study area and have hardly changed in recent years and decades, except for a moderate increase in the number of poplar plantations and an incipient abandonment of meadows and hedges.…”

Hedgerow age affects the species richness of herbaceous forest plants

“…In our study, only the proportion of forest species that are dispersed by epizoochory was higher in recent hedgerows than in ancient hedgerows. As hedgerows form linear landscape elements that are widely used as migration corridors by mammals (Burel, ), the potential of epizoochory is high (Hernández & Zaldívar, ). Wehling and Diekmann (2009b) found epizoochory and anemochory to be the most prominent dispersal types in hedgerows, and Graae () concluded that tall species with epizoochorous seeds are well adapted for the colonisation of new forest habitats.…”