Vertebrate‐mediated seed rain and artificial perches contribute to overcome seed dispersal limitation in a Mediterranean old field

Abstract

Natural regeneration of vegetation is a frequent outcome of land abandonment, although the rate and diversity of such regeneration may be severely restricted by seed dispersal limitation, among other factors. In spite of this, studies aiming to quantify seed rain and test methods to enhance it, such as artificial perches, are still underrepresented in the Mediterranean. In our study, we quantified seed rain density and richness and tested the effects of artificial perches on such rain over a distance gradient on seven Mediterranean island old fields. In each of the seven sites, we positioned three sampling stations, each consisting of 1 seed trap under an artificial perch and 1 as a control on the ground, distributed at 30, 60, and 90 m from natural vegetation remnant. All traps received seeds, suggesting no overall dispersal limitation. Of the 11 seed species found, 10 were fleshy‐fruited and dispersed by vertebrates. Seed traps under perches received significantly higher seed rain of fleshy‐fruited species dispersed by birds, while ground traps received significantly more seeds of the species also dispersed by mammals, especially Rubus ulmifolius. The distance from the seed source was nonsignificant in all cases. Our study demonstrates the key role of vertebrate‐mediated seed dispersal services to overcome dispersal limitation in old fields, as well as the effective contribution of even small artificial perches in contrasting such limitation. The lack of differences over the distance gradient reveal that the upper spatial limit of dispersal limitation was not achieved.

Precision restoration: a necessary approach to foster forest recovery in the 21st century

“…3B). Other approaches to foster seed dispersal could be the distribution of artificial perches or piles of branches to attract dispersers (Vogel et al 2018; Castillo‐Escrivà et al 2019; La Mantia et al 2019), the maximization of the presence of species that produce attractive fruits for seed dispersers early after planting and/or continuously throughout the year (De Almeida & Viani 2021), to increase the connectivity between nuclei (Lindell et al 2013; Peña‐Domene et al 2016), offering seeds of interest to the dispersers in feeders (Silva et al 2020), or even the reintroduction of the disperser (Genes et al 2018; Mittelman et al 2020). In summary, accounting for the role of seed dispersers and precise mapping of biological legacies (see Step 1) may be key for the success of forest restoration, so we need to know with precision the functioning of the system in order to plan proper measures.…”

Seed Rain in a Degraded Mining Area: The Role of Bird Perches and Pioneer Trees

“…The comparison between means (total number of seeds and zoochoric seeds) was statistically different between artificial perch collectors and the other collectors, regardless of their location. This higher number of seeds in artificial perches underscores their nucleating function, as they effectively contributed to the entry of animal-dispersed seeds (HEELEMANN et al, 2012;GUIDETTI et al, 2016;LA MANTIA et al, 2019).…”

Can the Caper (Capparis spinosa L.) Still Be Considered a Difficult-to-Propagate Crop?

“…Caper propagation in natural habits is ensured by seed dispersal exerted by several animals attracted by the juicy flesh of caperberries, such as lizards, ants, wasps, birds, rats and rabbits [39][40][41][42] which transport and release the undigested seeds, thus enhancing the permeability of the seed coats, and ultimately increasing the seed germination rate. These plants obtained from seed exhibit a high degree of heterogeneity in morphophysiological traits that are conducive to species adaptation and resilience in wild habitats, and may be of extreme interest for breeding purposes, but decidedly not for the agronomic exigence of homogeneity.…”