01423nas a2200133 4500008004100000245007900041210006900120300001100189490000700200520097700207100001901184700001301203856007301216 2013 eng d00aEcological mechanisms underlying arthropod species diversity in grasslands0 aEcological mechanisms underlying arthropod species diversity in  a19 -360 v583 a

Arthropods are an important component of grassland systems, contributing significantly to biodiversity and ecosystem structure and function. Climate, fire, and grazing by large herbivores are important drivers in grasslands worldwide. Arthropod responses to these drivers are highly variable and clear patterns are difficult to find, but responses are largely indirect with respect to changes in resources, species interactions, habitat structure, and habitat heterogeneity resulting from interactions among fire, grazing, and climate. Here, we review these ecological mechanisms influencing grassland arthropod diversity. We summarize hypotheses describing species diversity at local and regional scales and then discuss specific factors that may affect arthropod diversity in grassland systems. These factors include direct and indirect effects of grazing, fire, and climate, species interactions, above- and belowground interactions, and landscape-level effects.

1 aJoern, Anthony1 aLaws, A. uhttps://www.annualreviews.org/doi/10.1146/annurev-ento-120811-15354002310nas a2200349 4500008004100000245005700041210005600098300001300154490000700167520136700174653001701541653002501558653001901583653002401602653002301626653001201649653001801661653001901679100001801698700001501716700001301731700001501744700001401759700001601773700001701789700001901806700001801825700002001843700001601863700001901879856006201898 2013 eng d00aInvertebrates, ecosystem services and climate change0 aInvertebrates ecosystem services and climate change a327 -3480 v883 a

The sustainability of ecosystem services depends on a firm understanding of both how organisms provide these services to humans and how these organisms will be altered with a changing climate. Unquestionably a dominant feature of most ecosystems, invertebrates affect many ecosystem services and are also highly responsive to climate change. However, there is still a basic lack of understanding of the direct and indirect paths by which invertebrates influence ecosystem services, as well as how climate change will affect those ecosystem services by altering invertebrate populations. This indicates a lack of communication and collaboration among scientists researching ecosystem services and climate change effects on invertebrates, and land managers and researchers from other disciplines, which becomes obvious when systematically reviewing the literature relevant to invertebrates, ecosystem services, and climate change. To address this issue, we review how invertebrates respond to climate change. We then review how invertebrates both positively and negatively influence ecosystem services. Lastly, we provide some critical future directions for research needs, and suggest ways in which managers, scientists and other researchers may collaborate to tackle the complex issue of sustaining invertebrate-mediated services under a changing climate.

10aBiodiversity10abioindicator species10aClimate change10aecosystem engineers10aecosystem services10ainsects10ainvertebrates10asustainability1 aPrather, C.M.1 aPelini, S.1 aLaws, A.1 aRivest, E.1 aWoltz, M.1 aBloch, C.P.1 aDel Toro, I.1 aHo, Chuan-Kai.1 aKominoski, J.1 aNewbold, T.A.S.1 aParsons, S.1 aJoern, Anthony uhttps://onlinelibrary.wiley.com/doi/abs/10.1111/brv.1200202406nas a2200133 4500008004100000245009600041210006900137300001300206490000800219520193600227100001302163700001902176856007702195 2012 eng d00aPredator-prey interactions in a grassland food chain vary with temperature and food quality0 aPredatorprey interactions in a grassland food chain vary with te a977 -9860 v1223 a

Because species interactions are often context-dependent, abiotic factors such as temperature and biotic factors such as food quality may alter species interactions with potential consequences to ecosystem structure and function. For example, altered predator–prey interactions may influence the dynamics of trophic cascades, affecting net primary production. In a three-year field experiment, we manipulated a plant–grasshopper–spider food chain in mesic tallgrass prairie to investigate the effects of temperature and food quality on grasshopper performance, and to understand the direct and indirect tritrophic interactions that contribute to trophic cascades. Because spiders are active at cooler temperatures than grasshoppers in our system, we hypothesized that predator effects would be strongest in cooled treatments, and weakest in warmed treatments. Grasshopper spider interactions were highly context-dependent and varied significantly with food quality, temperature treatment and year. Spiders most often reduced grasshopper survival in the cooled and ambient temperature treatments, but had little to no effect on grasshopper survival in the warmed treatments, as hypothesized. In some years, plants compensated for grasshopper herbivory and trophic cascades were not observed despite significant effects of predators on grasshopper survival. However, in the year they were observed, trophic cascades only occurred in cooled treatments where predator effects on grasshoppers were strongest. Predicting ecosystem responses to climate change will require an understanding of how temperature influences species interactions. Our results demonstrate that changes in daily temperature regimes can alter predator–prey interactions among arthropods with consequences for ecosystem processes such as primary production and the relative importance of top–down and bottom–up processes.

1 aLaws, A.1 aJoern, Anthony uhttps://onlinelibrary.wiley.com/doi/abs/10.1111/j.1600-0706.2012.20419.x02565nas a2200205 4500008004100000245011800041210006900159300001300228490000800241520171600249653001401965653001201979653003301991653003702024653001502061653001702076100001302093700001902106856023402125 2012 eng d00aVariable effects of dipteran parasitoids and management treatment on grasshopper fecundity in a tallgrass prairie0 aVariable effects of dipteran parasitoids and management treatmen a123 -1300 v1023 a

Grasshoppers host a number of parasitoids, but little is known about their impact on grasshopper life history attributes or how those impacts may vary with land use. Here, we report on a three-year survey of nine grasshopper species in a tallgrass prairie managed with fire and bison grazing treatments. We measured parasitoid prevalence and the impact of parasitoid infection on grasshopper fecundity to determine if grasshopper-parasitoid interactions varied with management treatment. Adult female grasshoppers were collected every three weeks from eight watersheds managed with different prescribed burning and grazing treatments. Grasshopper fecundity with and without parasitoids was estimated through dissections of reproductive tracts. Dipteran parasitoids from two families (Nemestrinidae and Tachinidae) were observed infecting grasshoppers. We found significant effects of grazing treatment, but not burn interval, on grasshopper-parasitoid interactions. Parasitoids were three times more abundant in watersheds with bison grazing than in ungrazed watersheds, and the relative abundance of nemestrinid and tachinid flies varied with grazing treatment. Parasitoid prevalence varied among grasshopper species from <0.01% infected (Mermiria bivittata) to 17% infected (Hypochlora alba). Parasitoid infection reduced individual grasshopper fecundity, with stronger effects on current reproduction than on past reproduction. Furthermore, current fecundity in parasitized grasshoppers was lower in grazed watersheds compared to ungrazed watersheds. Nemestrinid parasitoids generally had stronger impacts on grasshopper fecundity than tachinid parasitoids, the effects of which were more variable.

10agrassland10aGrazing10ahost-parasitoid interactions10aKonza Prairie Biological Station10aOrthoptera10areproduction1 aLaws, A.1 aJoern, Anthony uhttps://www.cambridge.org/core/journals/bulletin-of-entomological-research/article/variable-effects-of-dipteran-parasitoids-and-management-treatment-on-grasshopper-fecundity-in-a-tallgrass-prairie/EB1AD93DB7D975E1009489797D88DF2E02323nas a2200193 4500008004100000245007900041210006900120300001300189490000700202520169800209653003701907653001701944653001501961653001501976653001701991100001302008700001902021856008902040 2011 eng d00aGrasshopper fecundity responses to grazing and fire in a tallgrass prairie0 aGrasshopper fecundity responses to grazing and fire in a tallgra a979 -9880 v403 a

Grasshopper abundance and diversity vary with management practices such as fire and grazing. Understanding how grasshopper life history traits such as fecundity respond to management practices is key to predicting grasshopper population dynamics in heterogeneous environments. Landscape-level experimental fire and bison grazing treatments at the Konza Prairie Biological Station (Manhattan, KS) provide an opportunity to examine how management affects grasshopper fecundity. Here we report on grasshopper fecundity for nine common species at Konza Prairie. From 2007 to 2009, adult female grasshoppers were collected every 3 wk from eight watersheds that varied in fire and grazing treatments. Fecundity was measured by examining female reproductive tracts, which contain a record of past and current reproductive activity. Body size was a poor predictor of fecundity for all species. Despite large differences in vegetation structure and composition with management regime (grazing and fire interval), we observed little effect of management on grasshopper fecundity. Habitat characteristics (grasshopper density, vegetation biomass, and vegetation quality; measured in 2008 and 2009) were better predictors of past fecundity than current fecundity, with species-specific responses. Fecundity increased throughout the summer, indicating that grasshoppers were able to acquire sufficient nutritional resources for egg production in the early fall when vegetation quality is generally low. Because fecundity did not vary across management treatments, population stage structure may be more important for determining population level reproduction than management regime at Konza Prairie.

10aKonza Prairie Biological Station10alife-history10amanagement10aOrthoptera10areproduction1 aLaws, A.1 aJoern, Anthony uhttps://academic.oup.com/ee/article-abstract/40/5/979/412531?redirectedFrom=fulltext