Vegetation richness, diversity, and structure influence arthropod communities of native and restored northern mixed‐prairies

Abstract

We studied the effects of vegetation species richness, diversity, and structure on grassland arthropod communities of 23 sites in northeastern South Dakota and southeastern North Dakota. Sites were selected to represent a vegetation species diversity gradient, and three vegetation cover types, including native unseeded grassland, low‐diversity seeding known as dense nesting cover (DNC) for waterfowl, and high‐diversity seed mix. During July of 2016, pan traps and sweep nets were used to survey the grassland arthropod community. A total of 25,521 arthropods representing 107 taxonomic families were collected. Richness, diversity, and biomass of arthropods did not differ among cover types. Vegetation richness and diversity, cover type, percent live vegetation and native cover, and litter depth were important predictors of arthropod community measures, and multivariate analysis of the arthropod community indicated significant differences between native and DNC study sites; explained by differences in vegetation richness, percent forb cover, and litter depth. Results of our study suggest that species richness of grassland restoration seeding mixes likely impacts arthropod richness and diversity, and DNC does not produce arthropod communities similar to native prairie. Additionally, because vegetation structural variables were important determinants of arthropod community measures, grassland management practices will influence the resulting arthropod community and influence the success of grassland restoration using high‐diversity seed mixes. Results of our study promote the potential for successful restoration outcomes using high‐diversity seed mixes, and indicate that low‐diversity, non‐native seed mixes, such as DNC, do not fully restore native grassland arthropod communities.

Vegetation diversity and structure influence small‐mammal communities in native and restored northern mixed grasslands

“…Results were also consistent with our second prediction that REF sites and HDM sites would have greater small‐mammal diversity compared to DNC sites. This pattern was consistent with the pattern observed in vegetation diversity at these sites (Minor et al 2021); thus, it is likely that the diversity of the vegetation community is influencing the diversity of the small‐mammal communities. In our study, time since seeding varied among cover types, with HDM sites seeded more recently than DNC sites.…”

“…Diversity of the small‐mammal community was higher at REF and HDM sites and positively correlated with vegetation species richness and diversity, which was consistent with our first prediction. Vegetation communities with greater diversity and heterogeneity should accommodate a greater number of wildlife species (Tilman et al 2001), and this hypothesis has been supported in studies of other grassland fauna (Siemann 1998, Schottler et al 2008, Minor et al 2021), although it remains relatively unexplored in small mammals.…”

“…Although the data did not provide evidence that HDM sites differed from REF sites, we observed a higher mean abundance of small mammals, particularly deer mice, at HDM sites compared to REF sites. Minor et al (2021) did not find evidence that vegetation diversity and richness differed between HDM and REF sites, but observed that HDM sites had lower mean diversity and richness values. It is possible that lower vegetation richness and diversity at seeded sites may explain higher estimates of small‐mammal abundance observed at the DNC and HDM sites.…”

“…One method commonly employed for restoring and promoting grassland vegetation diversity is the use of high‐diversity seeding (Larson et al 2011). While high‐diversity reconstruction does not restore grasslands to their native state (Barak et al 2018, Newbold et al 2020), several studies have suggested positive restoration outcomes (Barr et al 2017, Klopf et al 2017, Minor et al 2021), but research on grassland faunal responses to high‐diversity seeding remains limited. As such, many questions remain about the responses of higher trophic levels to high‐diversity reseeding restoration, and how to best plan restoration efforts to manage their populations.…”

“…We sought to determine the role of vegetation richness, diversity, cover type, and structure in shaping grassland small‐mammal communities, and to better understand how these variables may differentially influence focal taxa. We predicted that 1) richness and diversity of the small‐mammal community are positively correlated with vegetation species richness and diversity (Swab et al 2017, Port and Schottler 2017, Minor et al 2021); 2) unseeded reference (REF) and high‐diversity seed mix (HDM) sites have greater small‐mammal diversity than DNC sites (Minor et al 2021); 3) DNC sites have greater small‐mammal abundance than REF and HDM sites (Ceradini and Chalfoun 2017, Port et al 2019); 4) small‐mammal species composition would differ in response to vegetation richness, diversity, and structural variables (M'Closkey 1975, Glass and Eichholz 2021); and 5) small‐mammal communities of restored sites would differ from native grassland sites (Wolf et al 2018, Minor et al 2021).…”