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ABSTRACT AimThe species that compose local communities possess unique sets of functional and ecological traits that can be used as indicators of biotic and abiotic variation across space and time. Body size is a particularly relevant trait because species with different body sizes typically have different life history strategies and occupy distinct niches. Here we used the body sizes of non‐volant (i.e., non‐flying) terrestrial mammals to quantify and compare the body size disparity of mammal communities across the globe. LocationGlobal. Time PeriodPresent. Major Taxa StudiedNon‐volant terrestrial mammals. MethodsWe used IUCN range maps of 3982 terrestrial mammals to identify 1876 communities. We then combined diet data with data on climate, elevation and anthropogenic pressures to evaluate these variables' relative importance on the observed body size dispersion of these communities and its deviation from a null model. ResultsDispersion for these communities is significantly greater than expected in 54% of communities and significantly less than expected in 30% of communities. The number of very large species, continent, range sizes, diet disparity and annual temperature collectively explain > 50% of the variation in observed dispersion, whereas continent, the number of very large species, and precipitation collectively explain > 30% of the deviation from the null model. Main ConclusionsClimate and elevation have minimal predictive power, suggesting that biotic factors may be more important for explaining community body size distributions. However, continent is consistently a strong predictor of dispersion, likely due to it capturing the combined effects of climate, size‐selective human‐induced extinctions and more. Overall, our results are consistent with several plausible explanations, including, but not limited to, competitive exclusion, unequal distribution of resources, within‐community environmental heterogeneity, habitat filtering and ecosystem engineering. Further work focusing on other confounding variables, at finer spatial scales and/or within more causal frameworks is required to better understand the driver(s) of these patterns.
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Mammalian body size is determined by interactions between climate, urbanization, and ecological traits
Abstract Anthropogenically-driven climate warming is a hypothesized driver of animal body size reductions. Less understood are effects of other human-caused disturbances on body size, such as urbanization. We compiled 140,499 body size records of over 100 North American mammals to test how climate and human population density, a proxy for urbanization, and their interactions with species traits, impact body size. We tested three hypotheses of body size variation across urbanization gradients: urban heat island effects, habitat fragmentation, and resource availability. Our results demonstrate that both urbanization and temperature influence mammalian body size variation, most often leading to larger individuals, thus supporting the resource availability hypothesis. In addition, life history and other ecological factors play a critical role in mediating the effects of climate and urbanization on body size. Larger mammals and species that utilize thermal buffering are more sensitive to warmer temperatures, while flexibility in activity time appears to be advantageous in urbanized areas. This work highlights the value of using digitized, natural history data to track how human disturbance drives morphological variation.
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- Award ID(s):
- 1759898
- PAR ID:
- 10327382
- Date Published:
- Journal Name:
- Communications Biology
- Volume:
- 4
- Issue:
- 1
- ISSN:
- 2399-3642
- Format(s):
- Medium: X
- Sponsoring Org:
- National Science Foundation
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Accepted Manuscript1.0
- Journal Article:
- https://doi.org/10.1038/s42003-021-02505-3
