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Isotopic niche variation from the Holocene to today reveals minimal partitioning and individualistic dynamics among four sympatric desert mice.
J Anim Ecol 2018; 87(1):173-186JA

Abstract

Species interact with each other and their environment over a range of temporal scales, yet our understanding of resource partitioning and the mechanisms of species coexistence is largely restricted to modern time-scales of years to decades. Furthermore, the relative magnitudes of inter- vs. intraspecific variation in resource use are rarely considered, despite the potential for the latter to influence a species' ability to cope with changing environmental conditions. Modern desert rodent communities are thought to be strongly structured by competitive interactions, with niche partitioning of food resources hypothesized to explain the coexistence of multiple sympatric granivores. Yet the stability of niche dynamics over extended temporal scales within desert rodent communities is unknown. I examined the isotopic niche dynamics of four common sympatric desert mice (three granivores: Chaetodipus formosus, Perognathus longimembris and Reithrodontomys megalotis, and one omnivore: Peromyscus maniculatus) in the Smoke Creek Desert of northwestern Nevada using 13 C and 15 N isotopes obtained from "Modern" (2008-2013 CE), "Historical" (1989-2005 CE) and Holocene fossil specimens spanning the last c. 7,500 years. I found significant variation in niche position, niche breadth and interspecific niche overlap of these species through time. The niche breadth dynamics of the cricetids (P. maniculatus and R. megalotis) were positively correlated with one another, while the niche breadth dynamics of the heteromyid C. formosus were negatively correlated with those of all other species. Body size, dietary functional group, palaeoenvironmental trends and time-averaging provided little explanatory power. Importantly, Modern and Historical patterns of resource use and partitioning differed from Holocene baselines in terms of decreased niche overlap and in the absolute and relative position of each species' niche in at least one isotopic axis. These observations suggest that each species' resource use changed individualistically over the Holocene, hence niche dynamics are poorly explained by the hypothesis of temporally stable species interactions at millennial time-scales. Furthermore, changes to the resource base over the last century (likely due to the spread of invasive cheatgrass) may be increasing resource partitioning in the Modern, pushing species past their baseline ranges of resource use variation.

Authors+Show Affiliations

Department of Integrative Biology, Oregon State University, Corvallis, OR, USA.

Pub Type(s)

Journal Article

Language

eng

PubMed ID

29048750

Citation

Terry, Rebecca C.. "Isotopic Niche Variation From the Holocene to Today Reveals Minimal Partitioning and Individualistic Dynamics Among Four Sympatric Desert Mice." The Journal of Animal Ecology, vol. 87, no. 1, 2018, pp. 173-186.
Terry RC. Isotopic niche variation from the Holocene to today reveals minimal partitioning and individualistic dynamics among four sympatric desert mice. J Anim Ecol. 2018;87(1):173-186.
Terry, R. C. (2018). Isotopic niche variation from the Holocene to today reveals minimal partitioning and individualistic dynamics among four sympatric desert mice. The Journal of Animal Ecology, 87(1), pp. 173-186. doi:10.1111/1365-2656.12771.
Terry RC. Isotopic Niche Variation From the Holocene to Today Reveals Minimal Partitioning and Individualistic Dynamics Among Four Sympatric Desert Mice. J Anim Ecol. 2018;87(1):173-186. PubMed PMID: 29048750.
* Article titles in AMA citation format should be in sentence-case
TY - JOUR T1 - Isotopic niche variation from the Holocene to today reveals minimal partitioning and individualistic dynamics among four sympatric desert mice. A1 - Terry,Rebecca C, Y1 - 2017/11/16/ PY - 2017/06/07/received PY - 2017/10/08/accepted PY - 2017/10/20/pubmed PY - 2018/6/29/medline PY - 2017/10/20/entrez KW - Great Basin KW - conservation palaeobiology KW - holocene KW - isotopic niche KW - palaeoecology KW - prehistoric baselines KW - small mammals KW - stable isotopes SP - 173 EP - 186 JF - The Journal of animal ecology JO - J Anim Ecol VL - 87 IS - 1 N2 - Species interact with each other and their environment over a range of temporal scales, yet our understanding of resource partitioning and the mechanisms of species coexistence is largely restricted to modern time-scales of years to decades. Furthermore, the relative magnitudes of inter- vs. intraspecific variation in resource use are rarely considered, despite the potential for the latter to influence a species' ability to cope with changing environmental conditions. Modern desert rodent communities are thought to be strongly structured by competitive interactions, with niche partitioning of food resources hypothesized to explain the coexistence of multiple sympatric granivores. Yet the stability of niche dynamics over extended temporal scales within desert rodent communities is unknown. I examined the isotopic niche dynamics of four common sympatric desert mice (three granivores: Chaetodipus formosus, Perognathus longimembris and Reithrodontomys megalotis, and one omnivore: Peromyscus maniculatus) in the Smoke Creek Desert of northwestern Nevada using 13 C and 15 N isotopes obtained from "Modern" (2008-2013 CE), "Historical" (1989-2005 CE) and Holocene fossil specimens spanning the last c. 7,500 years. I found significant variation in niche position, niche breadth and interspecific niche overlap of these species through time. The niche breadth dynamics of the cricetids (P. maniculatus and R. megalotis) were positively correlated with one another, while the niche breadth dynamics of the heteromyid C. formosus were negatively correlated with those of all other species. Body size, dietary functional group, palaeoenvironmental trends and time-averaging provided little explanatory power. Importantly, Modern and Historical patterns of resource use and partitioning differed from Holocene baselines in terms of decreased niche overlap and in the absolute and relative position of each species' niche in at least one isotopic axis. These observations suggest that each species' resource use changed individualistically over the Holocene, hence niche dynamics are poorly explained by the hypothesis of temporally stable species interactions at millennial time-scales. Furthermore, changes to the resource base over the last century (likely due to the spread of invasive cheatgrass) may be increasing resource partitioning in the Modern, pushing species past their baseline ranges of resource use variation. SN - 1365-2656 UR - https://www.unboundmedicine.com/medline/citation/29048750/Isotopic_niche_variation_from_the_Holocene_to_today_reveals_minimal_partitioning_and_individualistic_dynamics_among_four_sympatric_desert_mice_ L2 - https://doi.org/10.1111/1365-2656.12771 DB - PRIME DP - Unbound Medicine ER -