ECS20-0454_R1_Hope et al_Isotope_Data.xlsx

Full isotopic dataset and museum specimen ID used in "Consumer roles of small mammals within fragmented native
tallgrass prairie"
Grassland ecosystems globally are being negatively impacted by changes
in climate, disturbance regimes, nutrient flux, and consumer guilds.
Changes in the trophic ecology of consumers can substantially influence
local resources, contributing to shifting diversity, community turnover,
and other processes of ecosystem change. Small mammals are diverse
and abundant within grasslands and yet the impact of changing
ecosystems on small mammals and the role of these mammals as
consumers, are still both under-studied. We assessed small mammal
resource use within grassland and woodland vegetation types that have
resulted from landscape-scale experimental disturbance through fire
treatments within the tallgrass prairie ecoregion of the North American
Great Plains. We predicted that resource use would vary significantly
among grassland vs. woodland communities, in turn reducing the role of
small mammals in contributing to future maintenance of native prairies.
We sampled five dominant species of rodents across three years and
multiple habitats. Using stable isotope analysis, we investigated isotopic
niche area and overlap to infer variation in diet, both within and among
species. Resource use shifted in bivariate isotopic space seasonally but
not across years when combining all species and habitats. Inferred
spring diet (based on fur samples) was highly diverse and overlapping.
Summer isotopic values (based on liver tissue) in woody habitat
treatments were narrower and overlapped less than within grassland
habitats. Consumers generally shifted from C4 herbivory to C3
herbivory, or greater omnivory, when analyzing grassland, shrubland,
and woodland habitats respectively. Within the tallgrass prairie
ecosystem, small mammal populations in herbaceous-dominated
habitats use a broader variety of resources than small mammals in
proximate woody-dominated habitats. As native grasslands experience
woody encroachment, small mammal assemblages experience turnover
of dominant species and associated changes in diet. Ecosystem changes
such as cessation of frequent fire resulting in more woody habitats may
include reduced roles by native small mammals as
consumers/dispersers/propagators of native grassland plants.