Seed dispersal by rodents in a lowland forest in central Panama

Abstract

Abstract:We studied the removal of seeds of three species of large-seeded tree (Astrocaryum standleyanum, Attalea butyracea and Dipteryx oleifera) from three different heights within six study plots in a lowland forest in central Panama. Fresh fruits with intact seeds fitted with industrial sewing bobbins were placed within semi-permeable exclosures. Removed seeds were tracked to deposition sites, and seed fate was determined. Removals were likely perpetrated by two small rodents, the strictly terrestrial Proechimys semispinosus and the scansorial Sciurus granatensis, because they were the most abundant small rodents in the study site during the study period and were of sufficient size to remove large seeds. Rodent abundance and fruit availability were estimated by conducting censuses. Nine microhabitat variables were measured at each deposition site to determine if these two rodents were preferentially depositing seeds in sites with certain characteristics or were randomly depositing seeds. During the study, rodents handled 98 seeds, 85 of which were not predated upon and could potentially germinate. Removal rates were not influenced by rodent abundance or fruit availability. Seeds were most frequently moved <3 m and deposited with the fruit eaten and the seed intact. However, some seeds did experience relatively long-distance dispersal (>10 m). Rodents preferentially deposited seeds in locations with large logs (>10 cm diameter), dense herbaceous cover, and an intact canopy. The number of large logs was different from random locations. Despite not being able to determine long-term fate (greater than c. 1 y), we show that these small rodents are not primarily seed predators and may in fact be important mutualists by dispersing seeds relatively long distances to favourable germination sites.

Food habits and endozoochorous seed dispersal by small rodents (Cricetidae and Echimyidae) in a riparian forest in southeastern Brazil

“…The six rodent species recognized as herbivorous or frugivorous (see Paglia et al 2012) presented a miscellaneous diet, consuming animal preys (arthropods), and plant items (fruits, leaves, stems, and flowers) in different proportions. A similar pattern was also reported for Cricetidae (Pinotti et al 2011;Sahley et al 2015) and Echimyidae rodents (Lessa and Costa 2009;Dittel et al 2015). However, it is important to highlight the high frequency of arthropod occurrence (100%) in the diet of the species studied, reinforcing its importance as a food resource for small neotropical rodents (Talamoni et al 2008;Lessa and Costa 2009;Pinotti et al 2011;Sahley et al 2015), especially in environments with a marked seasonality in resource availability, such as the Cerrado (see Pinheiro et al 2002;Lessa and Costa 2009).…”

“…Because of their feeding habits and abundance in Neotropical habitats, rodents can affect seed dispersal and the survival of several plant species, directly influencing their spatial distribution pattern (Brewer and Rejmanék 1999;Lessa and Costa 2009;Grenha et al 2010;Dittel et al 2015). Their potential as seed dispersers is mainly related to their habit of storing seeds for later consumption (synzoochory), i.e.…”

“…2008 Brewer andRejmanék 1999;Almeida and Galetti 2007;Haugaasen et al 2010). These animals can, however, also act as endozoochorous dispersers, consuming and dispersing viable seeds after gut passage (Horn et al 2008 Lessa andCosta 2009;Dittel et al 2015;Sahley et al 2016). In this context, rodents are particularly important and can act as dispersing agents, transporting seeds from one location to another (Horn et al 2008 Carvajal andAdler 2008;Lessa and Costa 2009;Dittel et al 2015;Sahley et al 2016), or also as mortality agents, damaging the seeds consumed (Briani and Junior 2007;Carvajal and Adler 2008;David et al 2015).…”

Landscape Disturbance Impacts on Attalea Butyracea Palm Distribution in Central Panama: Implications for Chagas Disease Transmission

“…We tested grid overlays at spatial resolutions of 5-m (an exact replicate of the underlying landscape raster), 30-m, 50-m, and 100-m; however, the 50-m spatial resolution best characterized palm distribution without including too much "empty" space (100m & 250m), or creating too many "islands" of non-contiguous occupied cells (30m). Additionally, A. butyracea propagation literature suggests an average of <10-m seed migration (by predators who feed on the surrounding eshy mesocarp) from the parent tree, with occasional migration up to 30 meters (45,46). We anticipate a cell size of 50m spatial resolution is large enough to pick up clusters of related palms within a single cell, or among neighboring cells.…”

Microhabitat selection for caching and use of potential landmarks for seed recovery by a neotropical rodent

“…Overall, the great majority of vertebrate‐buried seeds are recovered (Vander Wall, ). This might be influenced by the behavior of some scatter hoarders that select specific habitat characteristics for depositing the seeds (Manson & Stiles, ; Swartz, Jenkins & Dochtermann, ; Dittel, Lambert & Adler, ). These animals possibly recognize specific characteristics of the environment that can be used to recognize the site and facilitate finding the seeds later.…”