Introduction
Biodiversity declines are a significant consequence of the Anthropocene (Dirzo et al. 2014, Johnson et al. 2017, Wagner 2020). Major drivers of change in biological community composition during the Anthropocene include habitat loss (Marini et al. 2012), climate change (Andrew et al. 2013), and agriculture intensification (Tscharntke et al. 2012). Arthropod communities are not immune to these effects, experiencing the largest population fluctuations in recorded history, with steep declines of many functional groups (Hallmann et al. 2017, Leather 2018, Lister and Garcia 2018, Sánchez-Bayo and Wyckhuys 2019, Wagner 2020). As these drivers of biological community change do not appear likely to abate in the near future, vigilant monitoring of arthropod communities is essential for facilitating conservation efforts and stemming biodiversity declines. Inventories of biological communities (bioinventories) provide vital records for future assessments of biodiversity fluctuations as the Anthropocene continues.
Rangeland/pasture systems constitute > 413 million acres in the U.S., comprising ≈22% of the contiguous U.S. landmass (NASS 2017). Owing to the large footprint of pastures on the terrestrial landscape, management decisions made in pasture systems have important implications for arthropod diversity (Wallis De Vries et al. 2007, Jerrentrup et al. 2014). Historically, pastures once hosted robust arthropod communities (Walkden and Wilbur 1944, Rottman and Capinera 1983), providing refuge from intensively managed cropland in regions of the U.S. (Schmid et al. 2015). The diversity of flora in pastures provides a strong resource base and a wide variety of ecological niches for arthropod communities, making these grazed grasslands important reservoirs of arthropod biodiversity, in addition to their uses in supporting agricultural production (Dennis et al. 1998, Morris 2000, Wallis De Vries et al. 2007). The vegetation alone provides a diversity of microclimates, pollen, seeds, nectaries, and vegetation that attract a myriad of arthropods (Lundgren 2009). Arthropods inhabiting grassland ecosystems fulfill needed ecological functions to maintain ecosystem stability and productivity for livestock production (Whiles and Charlton 2006, Joern and Laws 2013). In the southeastern U.S. bioinventories of arthropods in pasture systems have been relegated to surveys of economically important insect groups (e.g., dung beetles, red imported fire ants, ticks, pest flies, etc.), while being confined to small regions or states (Wilson 1963, Kramer et al. 1985, Fiene et al. 2011, Kaufman and Wood 2012, Pompo et al. 2016, Steele 2016). Consequently, arthropod assemblages in pastures of the Southeast region of the U.S. remain poorly described. This inventory would not only serve livestock producers in the region, but also serve as an important bioinventory reference during this pivotal time of global arthropod declines. In this study, the arthropod community and functional guilds of foliar, soil, and dung arthropod communities found in Southeastern U.S. pastures are described.