Livestock grazing can be used as a key management tool for maintaining healthy ecosystems. However, the effectiveness of using grazing to modify habitat for species of conservation concern depends on how the grazing regime is implemented. Timing of grazing is one grazing regime component that is less understood than grazing intensity and grazer identity, but is predicted to have important implications for plant and higher trophic level responses. We experimentally assessed how timing of cattle grazing affected plant and arthropod communities in high-elevation grasslands of southwest Montana to better evaluate its use as a tool for multi-trophic level management. We manipulated timing of grazing, with one grazing treatment beginning in mid-June and the other in mid-July, in two experiments conducted in different grassland habitat types (i.e., wet meadow and upland) in 2011 and 2012. In the upland grassland experiment, we found that both early and late grazing treatments reduced forb biomass, whereas graminoid biomass was only reduced with late grazing. Grazing earlier in the growing season versus later did not result in greater recovery of graminoid or forb biomass as expected. In addition, the density of the most ubiquitous grassland arthropod order (Hemiptera) was reduced by both grazing treatments in upland grasslands. A comparison of end-of-season plant responses to grazing in upland versus wet meadow grasslands revealed that grazing reduced graminoid biomass in the wet meadow and forb biomass in the upland, irrespective of timing of grazing. Both grazing treatments also reduced end-of-season total arthropod and Hemiptera densities and Hemiptera biomass in both grassland habitat types. Our results indicate that both early and late season herbivory affect many plant and arthropod characteristics in a similar manner, but grazing earlier may negatively impact species of conservation concern requiring forage earlier in the growing season.
2011 Soil moisture and temperature
Soil moisture and temperature for wet meadow grassland sampling points in 2011. Cumulative soil moisture adds together data from sampling events 3 and 4. Data was collected in the field.
Soil data 2011 for R_with points not sampled deleted AND cumulative moist.csv
Plant data 2011
Aboveground plant biomass data for wet meadows in 2011 that has been scaled up to g/m2. Separated by grass, forbs, rush, iris, and woody vegetation. Graminoid scaled up is rush and grass data added together. Data was collected in the field.
Plant Biomass 2012
Aboveground plant biomass for upland grasslands in 2012 that shows original data and data that has been scaled up to g/m2. Separated by grass, forbs, rush, sedge, iris, and woody vegetation. Graminoid scaled up is rush, sedge, and grass data added together. Grass columns include both live and dead vegetation, while alive grass columns include only live vegetation that was determined via visual estimates when spread out over white paper. Data was collected in the field.
2012 arthropod biomass
2012 individual and total arthropod biomass (mg) for top 6 abundant orders WITHOUT ZEROS. Length and counts for arthropods were done in the lab and then standardized equations were applied to obtain weights.
2012 Arthropod new TOTAL arthropod biomass top 6 orders WITHOUT ZEROS.csv
2011 and 2012 precipitation and temperature
2011 and 2012 precipitation and temperature data from both years. Also a column for 30 year normal accumulated precipitation in mm. Data was obtained from PRISM.
Precipitation and temp both years PRISM.xlsx
2012 Plant height
Plant height 2012 in upland grasslands. Measured at 4 points at each sampling point and then an average was calculated. Data in cm and data collected in the field.
Plant height 2012 for R.csv
2012 Arthropod Abundance
2012 Arthropod Abundance data for each sampling point and sampling event. There are separate columns for each arthropod order. Numbers are counts. coleo=Coleoptera, colle=Collembola, de=Dermaptera, di=Diptera, ep= Ephemeroptera, he=Hemiptera, hy=Hymenoptera, le=Lepidoptera, or=Orthoptera, ps= Psocodea, s= spiders (Araneae), th=Thysanoptera. Data collected in the field and analyzed in the lab.
2011 Arthropod abundance
2011 Arthropod abundance for each sampling point and sampling event. There are separate columns for each arthropod order. Numbers are counts. coleo=Coleoptera, colle=Collembola, de=Dermaptera, di=Diptera, ep= Ephemeroptera, he=Hemiptera, hy=Hymenoptera, le=Lepidoptera, or=Orthoptera, ps= Psocodea, s= spiders (Araneae), th=Thysanoptera. Data collected in the field and analyzed in the lab.
2011 Arthropod biomass
2011 Arthropod biomass in wet meadow grasslands for each sampling point and sampling event. There are separate columns for each arthropod order. Numbers are biomass weights in mg. coleo=Coleoptera, colle=Collembola, de=Dermaptera, di=Diptera, ep= Ephemeroptera, he=Hemiptera, hy=Hymenoptera, le=Lepidoptera, or=Orthoptera, ps= Psocodea, s= spiders (Araneae), th=Thysanoptera. Arthropod orders are split up into size classes specific to each arthropod order. Data collected in the field and analyzed in the lab.
2012 Soil moisture and temperature
Soil moisture and temperature for all sampling points in 2012 for upland grasslands. Data was collected in the field.
Soil data 2012 for R.csv