Temporal niche overlap among insectivorous small mammals  

作　　者：Emerson M.VIEIRA Gabriela PAISE 

机构地区：[1]Laboratory of Ecology of Mammals,Zoology,University of Vale do Rio dos Sinos,São Leopoldo,Brazil [2]Graduate Program of Ecology,University of Campinas,Campinas,Brazil

出　　处：《Integrative Zoology》2011年第4期375-386,共12页整合动物学（英文版）

基　　金：This study was supported by British Ecological Society(SEPG#1841);UNISINOS and FAPERGS(0112763);While conducting this research work EM Vieira received a personal research grant from the Conselho Nacional de Pesquisa-CNPq(300286/99-6).All the methods used here comply with the current Brazilian laws on wildlife studies.

摘　　要：Being active in the same environment at different times exposes animals to the effects of very different environmental factors,both biotic and abiotic.In the present study,we used live traps equipped with timing devices to evaluate the potential role of biotic factors(competition and food abundance)on overall overlap in the temporal niche axis of 4 insectivorous small mammals in high-elevation grassland fields(‘campos de altitude’)of southern Brazil.Based on resources availability(invertebrates),data on animal captures were pooled in 2 seasons:‘scarcity’(June 2001−September 2001)and‘abundance’(November 2001-May 2002)seasons.We tested for non-random structure in temporal niche overlap among the species in each season.These species were the rodents Oxymycterus nasutus(Waterhouse,1837),Deltamys sp.,Akodon azarae(Fischer,1829),and the marsupial Monodelphis brevicaudis Olfers,1818.The studied community was mainly diurnal with crepuscular peaks.Simulations using the Pianka index of niche overlap indicated that the empirical assemblage-wide overlap was not significantly different from randomly generated patterns in the abundance season but significantly greater than expected by chance alone in the scarcity season.All the species showed an increase in temporal niche breadth during the abundance season,which appears to be related to longer daylength and high nocturnal temperatures.Patterns on both temporal niche overlap and temporal niche breadth were the opposite to those that we were expecting in the case of diel activity patterns determined by competition for dietary resources.Therefore,we conclude that competition did not seem to be preponderant for determining patterns of temporal niche overlap by the studied community.

关 键 词：activity patterns Brazil chronoecology community structure COMPETITION niche partitioning 

分 类 号：R32[医药卫生—人体解剖和组织胚胎学]