Many species of plants and animals associated with grasslands are rare or declining due to habitat loss and degradation. Although grassland plants and insects evolved in the context of both grazing and fire, the appropriate use of grazing and fire has been debated among those concerned with protecting insect communities. We established an experiment to test insect responses to three grassland management treatments: (1) patch‐burn graze (burning of spatially distinct patches and free access by cattle), (2) graze‐and‐burn (burning of entire tract with free access by cattle), and (3) burn‐only. Because we expected that land‐use legacies could also affect insect abundance and diversity, we evaluated effects of time since fire, grazing history, remnant history (remnant or reconstructed grassland) and pre‐treatment vegetation characteristics, which were assumed to be a legacy of prior land‐use. Butterflies (Lepidoptera), ants (Hymenoptera: Formicidae), and leaf beetles (Coleoptera: Chrysomelidae) were surveyed for three years to compare their responses to each of these treatments as measured by abundance, richness and species diversity. Each of these taxa is relatively diverse and was expected to have the potential to have strong negative responses to grazing and burning, but we predicted more positive responses to patch‐burn grazing. Our results showed that land‐use legacies affected insect abundance, richness and diversity, but treatments did not. Ant abundance was lower in tracts with a history of heavy grazing. Ant species richness was positively associated with pre‐treatment time since fire and vegetation height and negatively associated with pre‐treatment proportion native plant cover. Butterfly abundance was positively associated with pre‐treatment litter cover. Leaf beetle diversity was positively associated with pre‐treatment native plant cover, and leaf beetle abundance was negatively associated with time since fire. Our results indicate that land‐use legacies can exert more influence on grassland insect community composition than current management, but the particular aspects of these land‐use legacies that are important vary across insect taxa. The implications of these finding are that (1) land‐use legacies should garner more attention in grassland management and (2) conservation of grassland insect communities will be improved by taxon‐specific analysis of land‐use legacy variables.
Pastures dominated by tall fescue (Schedonorus phoenix (Scop.) Holub) cover much of the eastern United States, and there are increasing efforts to restore native grassland plant species to some of these areas. Prescribed fire and herbicide are frequently used to limit the growth of tall fescue and other non-natives, while encouraging native grasses and forbs. A fungal endophyte, commonly present in tall fescue, can confer competitive advantages to the host plant, and may play a role in determining the ability of tall fescue plants to persist in pastures following restoration practices. We compared vegetation composition among four actively restored subunits of a tall fescue pasture (each receiving different combinations of prescribed fire and/or herbicide) and a control. We also measured the rate of endophyte infection in tall fescue present within each restoration treatment and control to determine if restoration resulted in lower tall fescue cover but higher endophyte infection rates (i.e. selected for endophyte-infected individuals). Tall fescue cover was low in all restoration treatments and the control (1.1-17.9%). The control (unmanaged) had higher species richness than restoration treatments and plant community composition was indicative of succession to forest. Restoration practices resulted in higher cover of native warm season grasses, but in some cases also promoted a different undesirable species. We found no evidence of higher fungal endophyte presence in tall fescue following restoration, as all subunits had low endophyte infection rates (2.2-9.3%). Restoration of tall fescue systems using prescribed fire and herbicide may be used to promote native grassland species.
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