Primary seed dispersal by a sigmodontine rodent assemblage in a Peruvian montane forest

Catherine Teresa Sahley,Klauss Cervantes,Diego Paredes,Victor Pacheco,Alfonso Alonso,Edith Salas

doi:10.1017/s0266467416000043

Abstract

Abstract:We examined quantity and quality components of primary seed dispersal for an assemblage of sigmodontine rodents in a high-elevation montane tropical forest in Peru. We collected faecal samples from 134 individuals belonging to seven rodent species from the subfamily Sigmodontinae (Cricetidae) over a 2-y period. We conducted seed viability tests for seeds found in faecal samples. We identified seeds from eight plant families (Bromeliaceae, Annonaceae, Brassicaceae, Ericaceae, Melastomatacae, Myrtaceae, Rosaceae, Solanaceae), nine genera and 13 morphospecies. The most abundant seeds belonged toGaultheriasp. 1 (46% of total) andMiconiasp. 1 (31% of total), while the most viable seeds belonged toGreigiasp. (84% viability) andGuatteriasp. (80% viability). We utilized relative rodent abundance, seed species diversity, seed abundance and seed viability per rodent species to calculate an index of rodent disperser effectiveness, and found thatThomasomys kalinowskiiwas the most effective disperser, followed byAkodon torques,Calomys sorellus,Thomasomys oreas,Oligoryzomys andinusandMicroryzomys minutus. Plant genera dispersed by sigmodontine rodents overlapped more with bird- and terrestrial-mammal-dispersed plants than with bat-dispersed plants. Future neotropical seed dispersal studies should consider small rodents as potential seed-dispersers, especially in tropical habitats where small-seeded, berry-forming shrubs and trees are present.

Highlights

In neotropical rain forests, seed dispersal by rodents has been shown to play an important role in plant reproduction via scatterhoarding, seed caching and/or secondary seed dispersal (Forget 1990, 1992; Forget & Milleron 1991, Forget et al 2002, Jansen et al 2012)
We found that small sigmodontine rodents (
Our estimate of primary seed dispersal occurrence is likely conservative because a longer-term study examining diet found seeds from 17 morphospecies and nine families in faecal samples of all seven species at the same study site (Sahley et al 2015)

Summary

Introduction

In neotropical rain forests, seed dispersal by rodents has been shown to play an important role in plant reproduction via scatterhoarding, seed caching and/or secondary seed dispersal (Forget 1990, 1992; Forget & Milleron 1991, Forget et al 2002, Jansen et al 2012). Rodents shown to disperse seeds of neotropical plants via these mechanisms are generally medium- to large-bodied, and consume fruit and/or seeds of canopy tree species (Adler & Kestell 1998, Dittel et al 2015, Forget 1990, 1991, 1992; Haugaasen et al 2010, Hoch & Adler 1997, Smythe 1989). Small-bodied rodents, on the other hand, are widely considered to be seed predators (Demattia et al 2004, Denslow & Moermond 1982, Grenha et al 2010, Griscom et al 2007, Ostfeld et al 1997, Pinto et al 2009).

Methods

Results

Conclusion