Small mammal herbivores mediate the effects of soil nitrogen and invertebrate herbivores on grassland diversity

Poe, Nicole; Stuble, Katherine L.; Souza, Lara

Small mammal herbivores mediate the effects of soil nitrogen and invertebrate herbivores on grassland diversity

dc.contributor.author	Poe, Nicole
dc.contributor.author	Stuble, Katherine L.
dc.contributor.author	Souza, Lara
dc.date.accessioned	2019-02-27T18:56:49Z
dc.date.available	2019-02-27T18:56:49Z
dc.date.issued	2019
dc.description.abstract	Simultaneous reductions in herbivore abundance and increases in nitrogen deposition have led to radical shifts in plant communities worldwide. While the individual impacts of these human‐caused disturbances are apparent, few studies manipulate both herbivory and N, nor differentiate among herbivore guilds, to understand contingencies in the ability of these drivers to affect producer diversity and productivity. As such, understanding how the main and combined effects of increasing soil N with declining herbivores may influence plant community structure and function is critical to better understand the future of grassland ecosystems under multiple global change drivers. In this study, we asked: (a) What are the main effects of small mammal herbivores, invertebrate herbivores, and soil N on plant community structure and function? and (b) Are the effects of invertebrate herbivores and soil N on plant community structure and function contingent on small mammal herbivory? We used a nested design, with invertebrate and soil N treatments nested within small mammal manipulations in an existing tallgrass prairie. We measured plant community structure by quantifying plant richness, evenness, diversity, and composition across two full growing seasons. We also recorded total aboveground biomass to quantify grassland productivity. We found that small mammal herbivores strongly shaped plant diversity, species composition, and productivity. Small mammal herbivores also mediated the effects of soil N and invertebrate herbivores on grassland community structure, but not composition or productivity. Small mammal reduction lowered plant species richness while increasing aboveground biomass and altering compositional similarity. Invertebrate herbivores, in the presence of small mammals, promoted plant dominance by reducing evenness without altering compositional similarity. Additionally, soil nitrogen addition reduced plant richness, but only when small mammals were reduced, and no effects were detected on compositional similarity or productivity. Our findings provide further evidence that temperate grasslands can be strongly influenced by consumers, and that consumers mediate the effects of resources as well as other consumer guilds on producer evenness and richness. Taken together, we provide evidence of strong contingencies in the drivers of grassland structure, with small mammals directly altering plant diversity as well as mediating the effects of soil nitrogen and invertebrate herbivory on plant richness and evenness. Therefore, we suggest it is imperative to consider how consumer guilds and resource types may interact to shape grassland plant communities.	en_US
dc.description.peerreview	Yes	en_US
dc.description.sponsorship	Funding was provided by the University of Oklahoma (Junior Faculty Fellowship to LS) and Oklahoma Biological Survey. Article processing charges funded in part by University of Oklahoma Libraries	en_US
dc.identifier.citation	Poe N, Stuble KL, Souza L. Small mammal herbivores mediate the effects of soil nitrogen and invertebrate herbivores on grassland diversity. Ecol Evol. 2019;00:1–11. https://doi.org/10.1002/ece3.4991	en_US
dc.identifier.doi	10.1002/ece3.4991	en_US
dc.identifier.uri	https://hdl.handle.net/11244/317563
dc.language	en_US	en_US
dc.rights	Attribution 4.0 International	*
dc.rights.uri	http://creativecommons.org/licenses/by/4.0/	*
dc.subject	aboveground biomass	en_US
dc.subject	compositional similarity	en_US
dc.subject	grassland	en_US
dc.subject	herbivores	en_US
dc.subject	invertebrates	en_US
dc.subject	plant diversity	en_US
dc.subject	plant evenness	en_US
dc.subject	plant richness	en_US
dc.subject	small mammals	en_US
dc.subject	soil nitrogen	en_US
dc.title	Small mammal herbivores mediate the effects of soil nitrogen and invertebrate herbivores on grassland diversity	en_US
dc.type	Article	en_US
ou.group	College of Arts and Sciences::Department of Microbiology and Plant Biology	en_US