Mast seeding and predator-mediated indirect interactions in a forest community: evidence from post-dispersal fate of Rodent-generated caches.

Abstract

The impact of temporal variations in seed supply on rates of seed removal by rodents (Apodemus speciosus and Eothenomys andersoni) was examined to demonstrate that seed predation on Aesculus turbinata can depend on the seed abundance of other dominant tree species. The impact of seasonal variation in Fagus crenata seed fall was examined, in particular. Research was undertaken in two sites within the Kanumazawa Riparian Research Forest in Japan. Seed production of the three tree species (A. turbinata, F. crenata and Quercus mongolica) was recorded annually from 1992 to 1998 in the long-term monitoring plot. In each of the 3 years (1995-97), the fate of approximately 100 seeds of A. turbinata were monitored under each of the five mature trees in the short-term plot. The seed success of A. turbinata varied greatly among the 7 years of the study. Both A. turbinata seed survival and seedling emergence were particularly low during the F. crenata mast year and among the lowest in the 7-year observation period. No such trend was observed when Q. mongolica massively fruited. Only in 1996 were more seeds initially destroyed (60%) than cached. Seed predation was the predominantly source of seed mortality, accounting for between 93 and 100% of seed death. Although the fate of all seeds was not known, the proportion of seeds that germinated was low, ranging from only 1 to 3% with over 80% of seeds suffering predation in most years. In 1995, the rate of A. turbinata seed removal suddenly decreased in October despite an abundance of seeds. Rodents exhibited a strong, consistent preference to F, crenata seeds over A. turbinata and this preference increased as F. crenata seed became more abundant. results indicate that there was no clear relationship between rodent abundance and any of the seed fall measures, although their populations increased rapidly in the summer following F. crenata masting.

Advantages of masting in European beech: timing of granivore satiation and benefits of seed caching support the predator dispersal hypothesis

“…Beech masting satiated rodents during the phase of seed consumption from caches, supporting the second prediction of the seed dispersal hypothesis. This result is consistent with several other studies (Theimer 2001;Vander Wall 2002;Jansen et al 2004;Yi et al 2011), but contrasts with Xiao et al (2013), who rejected the predator dispersal hypothesis largely on the basis of a decline in survival of cached seeds after mast years (see also Hoshizaki et al 2002). As a caveat, our caching experiments simulated seed pilferage by naive consumers rather than seed retrieval by cache owners.…”

Effects of seed abundance on seed scatter-hoarding of Edward’s rat (Leopoldamys edwardsi Muridae) at the individual level

“…The predator satiation hypothesis proposes that producing massive crops of plants in mast years can satiate seed predators, which allows more seeds to be cached and so to escape predation by animals (Janzen 1970;Crawley and Long 1995;Sork 1993;Sork et al 1993;Theimer 2001;Kelly et al 2001;Schnurr et al 2002;Kelly and Sork 2002;Li and Zhang 2007). However, some studies have failed to support this hypothesis (e.g., Herrera et al 1994; Montiel and Montana 2000;Hoshizaki and Hulme 2002;Jansen 2003;Vander Wall 2002;Xiao et al 2005). Many co-varying factors, such as intra-or interspeciWc competitors, may aVect seed removal and hoarding by rodents under natural Weld conditions, and thus may aVect conclusions drawn from Weld observations.…”

Long‐term seed survival and dispersal dynamics in a rodent‐dispersed tree: testing the predator satiation hypothesis and the predator dispersal hypothesis

“…In addition to mast seeding, however, community-level seed abundance (i.e. seed crops from other plants) may have some impact on the population and behavioural responses of both seed predators and dispersers and subsequently on seed dispersal and survival dynamics in co-occurring plants (Hoshizaki & Hulme 2002;Xiao, Zhang & Wang 2005;Xiao et al 2006a). Therefore, future studies are also needed to understand better how community-level seed abundance interacts with seed predators and seed dispersers to predict seed dispersal and seed survival in animal-dispersed plants.…”

“…The procedures quantifying annual seed production of oil tea and annual rodent abundance are presented in Appendix S1 in the Supporting Information. We conservatively estimated the population of rodent seed predators and seed dispersers using the minimum number alive (MNA) per 100 trap-nights (see similar analysis in Hoshizaki & Hulme 2002).…”