Effects of precipitation, competition, and predation on the germination and establishment of a drylands-invasive grass from 2016-2018

This dataset was used to assess the germination and establishment of Eragrostis lehmanniana (Lehmann Lovegrass) under varied growing season precipitation, competition with native grasses, predator identity, and the interaction of these factors. Data were collected from 2016 to 2018 at a project area within the Jornada Experimental Range, a Long-Term Ecological Research site approximately 30 km north of Las Cruces, NM, USA (32 33037.4400 N, 106 46026.6500 W). The experimental site was dominated with Bouteloua eriopoda with scattered Neltuma glandulosa shrubs.

Thirty plots were established based on similarity of native grass cover and size of a central N. glandulosa shrub. This experiment utilized a split-plot design: precipitation was altered at the plot-level, competition was altered within each plot at the half-plot level, and predation treatments were established within each half-plot at the subplot-level. Precipitation treatments altered growing season precipitation (June to the end of September) using an automatic rainfall manipulation system (ARMS; Gherardi and Sala 2013). One of three precipitation treatments were randomly assigned to plots: -80% of ambient, ambient, +80% of ambient. Within each plot, competition from native grasses was altered at two levels: "control" plot-halves were unaltered, and "reduced" plot-halves were repeatedly clipped to reduce the competitive ability of native grasses through defoliation. Predator identity was manipulated by installing different exclosures within subplots to create four levels of predator-identify treatments: all predators, ant access, lagomorph access, and no predators. There were a total of 10 replicates of each precipitation, competition, and predation treatment combination (3 precipitation treatments * 2 competition treatments * 4 predation treatments * 10 replicates = 240 total subplots).