Exclusion of interspecific competition reduces scatter‐hoarding of Siberian chipmunk Tamias sibiricus: A field study

Abstract

Although food availability and the abundance of seed predators have been postulated to affect seed dispersal, it is not clear how seed‐eating animals modify their scatter‐hoarding strategies in response to different levels of interspecific competition. We placed paired germinated and ungerminated acorns of Quercus mongolica on 30‐cm high platforms to exclude potential interspecific competition of the predominant larder hoarders Apodemus peninsulae and Myodes rufocanus, to investigate seed dispersal by a predominant scatter‐hoarder, Tamias sibiricus, in the field in north‐eastern China. Our results showed that T. sibiricus ate more acorns in situ in the absence of interspecific competition. In the presence of interspecific competition of A. peninsulae and C. rufocanus, however, more acorns were scatter‐hoarded by T. sibiricus. Regardless of interspecific competition, germination of acorns showed no significant effects on seed dispersal patterns, inconsistent with the “seed perishability hypothesis” that animals avoid hoarding seeds with high perishability. Exclusion of interspecific competition, though relatively increasing the per capita seed abundance, appears to reduce seed dispersal, scatter‐hoarding and seedling establishment. Therefore, we propose that moderate interspecific competition rather than competition exclusion may benefit seed scatter‐hoarding and seedling establishment.

Squirrel-Seed Interactions: The Evolutionary Strategies and Impact of Squirrels as Both Seed Predators and Seed Dispersers

“…Exposed seeds on the ground were more likely to be scatter-hoarded by T. sibiricus, while pilfered seeds from artificial caches were more likely to be larder-hoarded than those easily accessible on the ground. Recently, Deng et al (2020) provided evidence that exclusion of interspecific competition by wood mice reduces seed dispersal and scatter-hoarding by Siberian chipmunks, despite an increase in per capita seed abundance. These studies collectively demonstrate that Siberian chipmunks show flexible behavioral strategies for hoarding in response to food availability.…”

Radicle pruning by seed‐eating animals helps oak seedlings absorb more soil nutrient

“…All acorns were stored at 4 °C until the germination experiment. Acorns of these oak species have been reported to be subjected to radicle pruning by several seed-eating rodents (Yang et al 2012;Zhang et al 2016Zhang et al , 2017aDeng et al 2020).…”

A new technique for stain-marking of seeds with safranine to track seed dispersal and seed bank dynamics

“…Several methods have been developed for the study of seed dispersal; these include the surgical implantation of magnets ( Alverson and Díaz, 1989 ), attachment of colored threads or tags to seeds ( Forget, 1992 ; Hirsch et al, 2012a ; Deng et al, 2020 ), radioisotope labeling ( Vander Wall, 1994 ), fluorescent microsphere and dye powder labeling ( Levey and Sargent, 2000 ), stable isotope ( 15 N) analysis ( Carlo et al, 2009 ; Wang et al, 2021 ), attachment passive integrated transponders (PITs) tags ( Suselbeek et al, 2013 ); and molecular or genetic marking ( Ouborg et al, 1999 ; Godoy and Jordano, 2001 ; Grivet et al, 2005 ; Hardesty et al, 2006 ). These methods can help researchers to match dispersed seeds and seedlings with their parent plants in some situations; however, most are prohibitively expensive, logistically intractable, or excessively laborious and time consuming.…”