Dataset: ASU Fragmentation – Squidpop Consumption Probability

To measure generalist consumption probabilities across landscapes, we conducted two squidpop consumption assays on 19-Oct and 1-Nov 2018 on Oscar Shoal and an adjacent unnamed shoal in Back Sound, NC, USA (34°42′20" N to 34°41′60" N, 76°36′ 15" W to 76°35′17" W). Consumption assays were conducted after Hurricane Florence disturbed our landscapes (see below), prior to the seasonal egress of nekton from local seagrass meadows (Baillie et al., 2015). Squidpops are 1-centimeter × 1-centimeter squares of dried squid mantle tied to 1-centimeter segments of monofilament (Duffy et al., 2015). Squidpops were secured to 60-centimeter long, 0.5-centimeter diameter, fiberglass stakes with attached floats for relocation. On each assay date, up to 10 squidpops were deployed within ASUs in each landscape, 1 meter apart and less than 0.5 meters from the ASU-matrix interface (the edge of ASU patches), to control for potentially different consumption probabilities between seagrass patch edges and interiors (Mahoney et al., 2018). The number of squidpops deployed in each landscape [mean of 9.2 ± 1.8 SD] depended upon the length of the available edge. Squidpop presence/absence was checked after 1 hour, 2 hours, and 3 hours to retrospectively assess the timeframe in which overall consumption probabilities allowed for the resolution of differences in consumption among sites (i.e., between one- and two-thirds of all bait consumed). This threshold was met after 1 hour, therefore we focus our results on these data. All absent squidpops were presumed eaten based on previous efforts that have demonstrated negligible spurious bait loss (Lefcheck et al., 2021).

The study area and artificial landscapes were directly impacted by Hurricane Florence during 13-16 Sept 2018. Despite ASU re-enforcements made prior to Florence's landfall (i.e., additional lawn staples and cable ties), our landscapes experienced substantial disturbance akin to natural seagrasses in the vicinity, in many cases completely removing or burying ASUs which altered the landscape percent cover and fragmentation per se parameters. We recalculated landscape parameters based on ASU-by-ASU checks made after Hurricane Florence. Holding the original landscape 234-square meter footprint constant, the percent cover and percolation probability of each landscape was recalculated from the remaining number of ASUs (excluding buried ASUs). 

Known Issues:
Artificial seagrass landscapes were substantially altered by Hurricane Florence; therefore, landscape parameters were recalculated based on ASU-to-ASU checks. For the purposes of squidpop consumption analysis, buried ASUs were excluded from parameter calculations (as buried ASUs were not expected to influence above-ground fauna).