Dangerous life at the edge: Implications of seed predation for roadside revegetation

Abstract

Question: Anthropogenic edges caused by transport infrastructure such as dirt roads and trails (also known as Soft Linear Developments; SLD) are pervasive in almost every terrestrial ecosystem. Revegetating these edges may reduce some of their negative effects, such as their permeability to biological invasions and detrimental effects on wildlife, potentially becoming suitable habitat for a broad range of species. Selecting species with low post-dispersal seed predation rates may improve the effectiveness of revegetation programmes. Location: Mediterranean scrublands in SW Spain. Methods:We made offerings of a total of 16,000 seeds of eight species of fleshy-fruit shrubs both along SLD edges and scrubland interiors in two independent blocks in each of three distant locations. Using four types of selective enclosure, we assessed the relative contribution of three seed predator guilds (ants, rodents and birds) to seed predation rates both along SLD edges and scrubland interiors. Results:The effects of anthropogenic edges on seed predation rates were speciesspecific. The large and hard-seeded species Chamaerops humilis was not predated at all. Juniperus phoenicea and Corema album seeds had higher predation rates in scrubland interiors than in edges. The small-seeded Rubus ulmifolius experienced relatively low seed predation rates compared to the other species. Predation rates for this species were higher along SLD edges than in scrubland interiors. Ants were the main seed predators in the area, and showed marked preferences for J. macrocarpa and C. album seeds at both SLD edges and scrubland interiors. Conclusions:Our results show the strong context-dependency of seed predation rates in both SLD edges and scrubland interiors, and thus the importance of well spatially and temporally replicated studies. Species with large and hard seeds may be good candidates for roadside revegetation programmes. However, the relative suitability of plant species would depend on the seed predator community. Our findings confirm that studies on seed predation may help planning cost-effective species selection for edge revegetation efforts worldwide.

Coping with changing plant–plant interactions in restoration ecology: Effect of species, site, and individual variation

“…We found seed–seedling conflicts (Drezner, 2015; Schupp, 1995) beneath Chamaerops humilis for seven Mediterranean woody plant species. The higher seed survival seen in adjacent open spaces compared with beneath Chamaerops humilis was primarily due to rodents, which usually predate seeds beneath shrubs (Fedriani et al, 2020; Suárez‐Esteban et al, 2018). The thorny and shading microhabitat beneath Chamaerops humilis represents a safe site for rodents by sheltering them from predators (Brown & Kotler, 2004; but see Ziffer‐Berger et al, 2017).…”

“…Dispersed seeds in Doñana are often consumed by rodent species such as Apodemus sylvaticus , Mus spretus , and Rattus spp. (Fedriani et al, 2020; Suárez‐Esteban et al, 2018). Seedlings usually emerge during the late winter and spring, and most die during summer owing to extreme drought and severe temperatures.…”

“…Each year, we recorded the number of remaining seeds early in the morning during four consecutive (non‐rainy) days (see Appendix for additional details). Based on observations of hulls from predated seeds, rodent droppings, and the absence of elaiosomes in the offered seeds, we assumed that seed removal was equivalent to seed predation (Suárez‐Esteban et al, 2018; but see Vander Wall et al, 2005).…”

The overlooked benefits of synzoochory: rodents rescue seeds from aborted fruits

“…Several species of generalist rodents (e.g., Apodemus sylvaticus , Mus spretus , Rattus spp., and Eliomys quercinus ) are known to feed on dispersed seeds from ripe fleshy fruits (Suárez‐Esteban et al, 2018, Garrote et al 2018). Rodents often gnaw P. bourgaeana aborted fruits along their longitudinal axis taking all or, most often, some of their seeds; thus, rodents recurrently leave some partially gnawed fruits with uneaten seeds (Fig.…”

Germinación de semillas de especies nativas colonizadoras de taludes viales del noroeste patagónico

“…Ecología Austral 34:052-065 Debido a que la distribución de las variables inicio, porcentaje y tiempo medio de germinación no cumplieron con los supuestos de normalidad y homogeneidad de varianzas necesarios para realizar pruebas paramétricas, se compararon las medianas de los grupos con las pruebas no paramétricas de Kruskal-Wallis y Mann-Whitney. En los casos en que se encontraron diferencias significativas se aplicaron comparaciones múltiples de a pares de los rangos promedio (Siegel and Castellan 1995). Se utilizó el software SPSS versión 23.0 para Windows (IBM 2015).…”