Pine seed removal in fragments of three temperate plant communities

Abstract

Background: Foraging strategies may vary among guilds of granivores and impact the tree recruitment and biodiversity of plant communities.
 Hypothesis : The hypotheses were: during the night in areas with tree cover rodents will be the main seed removers, insects in open areas at night, and birds in all types of plant communities during the daytime. 
 Studied species/Data description/Mathematical model: The seed removal by birds, rodents and insects was studied in a Mexican temperate forest. In order to detect differences in seed removal of Pinus patula , P. pseudostrobus , P. teocote and P. montezumae, a GLMM model with three way interaction (type of plant community, exclusion treatment and period) was carried out for each pine seed species where random variables were the variation among sites and months. 
 Study site and years of study: This study was carried out in a Mexican temperate forest during February 2006 and January 2007.
 Methods : Through exclusion treatments we evaluated the seed removal of four pine species in three plant communities with two replicates (1 ha approximately) and two periods.
 Results : The three-way interaction was significant for all pine species ( P < 0.001) (GLMM processes). The variance was greater among sites than between months. The main seed removers for all pine seed species, were: At night insects for subalpine grassland; during the daytime birds for all plant communities, and at night the rodents in pine forest, oak-alder forest and finally in the subalpine grassland. 
 Conclusions : The rodents were the main seeds removers in areas with tree cover during the night, the insects in open areas at night, and birds in all plant communities during the daytime.