Carbon isoscapes of rodent diets in the Great Plains USA deviate from regional gradients in C4 grass abundance due to a preference for C3 plant resources

Haveles, Andrew W.; Fox, David L.; Fox-Dobbs, Kena

doi:10.1016/j.palaeo.2019.04.003

Cited by 7 publications

(6 citation statements)

References 53 publications

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“…Modern Sigmodon are highly selective of grass habitats, and (C 3 or C 4 ) grasses can account for ~80% of their diet, but this species consumes higher quality dicots when available (Petersen 1973, Kincaid and Cameron 1982, Kincaid et al 1983, Randolph et al 1991, Cameron and Eshelman 1996. Historically, Sigmodon hispidus has been found to utilize a mix of C 3 and C 4 resources across the Great Plains, with regions of greater C 4 abundance being associated with higher δ 13 C values in Sigmodon (Haveles et al 2019). The observed variation in δ 13 C values suggests that Sigmodon is not constrained to only consume C 4 grasses (Fig.…”

Section: Discussionmentioning

confidence: 99%

Changes in the diet and body size of a small herbivorous mammal (hispid cotton rat,Sigmodon hispidus) following the late Pleistocene megafauna extinction

et al. 2019

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The catastrophic loss of large‐bodied mammals during the terminal Pleistocene likely led to cascading effects within communities. While the extinction of the top consumers probably expanded the resources available to survivors of all body sizes, little work has focused on the responses of the smallest mammals. Here, we use a detailed fossil record from the southwestern United States to examine the response of the hispid cotton rat Sigmodon hispidus to biodiversity loss and climatic change over the late Quaternary. In particular, we focus on changes in diet and body size. We characterize diet through carbon (δ13C) and nitrogen (δ15N) isotope analysis of bone collagen in fossil jaws and body size through measurement of fossil teeth; the abundance of material allows us to examine population level responses at millennial scale for the past 16 ka. Sigmodon was not present at the cave during the full glacial, first appearing at ~16 ka after ice sheets were in retreat. It remained relatively rare until ~12 ka when warming temperatures allowed it to expand its species range northward. We find variation in both diet and body size of Sigmodon hispidus over time: the average body size of the population varied by ~20% (90–110 g) and mean δ13C and δ15N values ranged between −13.5 to −16.5‰ and 5.5 to 7.4‰ respectively. A state–space model suggested changes in mass were influenced by diet, maximum temperature and community structure, while the modest changes in diet were most influenced by community structure. Sigmodon maintained a fairly similar dietary niche over time despite contemporaneous changes in climate and herbivore community composition that followed the megafauna extinction. Broadly, our results suggest that small mammals may be as sensitive to shifts in local biotic interactions within their ecosystem as they are to changes in climate and large‐scale biodiversity loss.

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Section: Discussionmentioning

confidence: 99%

Changes in the diet and body size of a small herbivorous mammal (hispid cotton rat,Sigmodon hispidus) following the late Pleistocene megafauna extinction

et al. 2019

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“…Climate change is anticipated to drastically shift the competitive advantage of C 3 and C 4 plants in Australia and globally, leading to substantial changes in species distribution (Corlett and Westcott 2013;Hasegawa et al 2018). This will likely drive significant bottom-up changes to the structure and diversity of faunal communities (Haddad et al 2009;Warne et al 2010;Haveles et al 2019). Using our underlying climate models, C 3 and C 4 abundance can be extrapolated under future conditions and areas that are most vulnerable to extreme changes in C 3 and C 4 cover can be identified.…”

Section: Applicationsmentioning

confidence: 99%

A vegetation carbon isoscape for Australia built by combining continental-scale field surveys with remote sensing

et al. 2022

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Context Maps of C3 and C4 plant abundance and stable carbon isotope values (δ13C) across terrestrial landscapes are valuable tools in ecology to investigate species distribution and carbon exchange. Australia has a predominance of C4-plants, thus monitoring change in C3:C4 cover and δ13C is essential to national management priorities. Objectives We applied a novel combination of field surveys and remote sensing data to create maps of C3 and C4 abundance in Australia, and a vegetation δ13C isoscape for the continent. Methods We used vegetation and land-use rasters to categorize grid-cells (1 ha) into woody (C3), native herbaceous, and herbaceous cropland (C3 and C4) cover. Field surveys and environmental factors were regressed to predict native C4 herbaceous cover. These layers were combined and a δ13C mixing model was used to calculate site-averaged δ13C values. Results Seasonal rainfall, maximum summer temperature, and soil pH were the best predictors of C4 herbaceous cover. Comparisons between predicted and observed values at field sites indicated our approach reliably predicted generalised C3:C4 abundance. Southern Australia, which has cooler temperatures and winter rainfall, was dominated by C3 vegetation and low δ13C values. C4-dominated areas included northern savannahs and grasslands. Conclusions Our isoscape approach is distinct because it incorporates remote sensing products that calculate cover beneath the canopy, the influence of local factors, and extensive validation, all of which are critical to accurate predictions. Our models can be used to predict C3:C4 abundance under climate change, which is expected to substantially alter current C3:C4 abundance patterns.

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“…Global warming is expected to alter the competitive advantage of plants with different photosynthetic pathways [14][15][16] , changing species distributions and community composition, and leading to significant bottom-up effects on the structure, diversity and function of terrestrial communities [17][18][19] . Thus, the ecology and evolution of these different pathways has become a focus of recent botanical research [20][21][22] .…”

Section: Background and Summarymentioning

confidence: 99%

The photosynthetic pathways of plant species surveyed in Australia’s national terrestrial monitoring network

et al. 2021

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The photosynthetic pathway of plants is a fundamental trait that influences terrestrial environments from the local to global level. The distribution of different photosynthetic pathways in Australia is expected to undergo a substantial shift due to climate change and rising atmospheric CO2; however, tracking change is hindered by a lack of data on the pathways of species, as well as their distribution and relative cover within plant communities. Here we present the photosynthetic pathways for 2428 species recorded across 541 plots surveyed by Australia’s Terrestrial Ecosystem Research Network (TERN) between 2011 and 2017. This dataset was created to facilitate research exploring trends in vegetation change across Australia. Species were assigned a photosynthetic pathway using published literature and stable carbon isotope analysis of bulk tissue. The photosynthetic pathway of species can be extracted from the dataset individually, or used in conjunction with vegetation surveys to study the occurrence and abundance of pathways across the continent. This dataset will be updated as TERN’s plot network expands and new information becomes available.

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Carbon isoscapes of rodent diets in the Great Plains USA deviate from regional gradients in C4 grass abundance due to a preference for C3 plant resources

Cited by 7 publications

References 53 publications

Changes in the diet and body size of a small herbivorous mammal (hispid cotton rat,Sigmodon hispidus) following the late Pleistocene megafauna extinction

Changes in the diet and body size of a small herbivorous mammal (hispid cotton rat,Sigmodon hispidus) following the late Pleistocene megafauna extinction

A vegetation carbon isoscape for Australia built by combining continental-scale field surveys with remote sensing

The photosynthetic pathways of plant species surveyed in Australia’s national terrestrial monitoring network

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