Dataset: Richness of marine invertebrate communities across latitude with exposure to predation

Methodology:

Marine invertebrate communities developed on PVC settlement panels (14 x 14 cm) hung on floating docks one meter below the water surface at local marinas at three coastal sites in each region. Communities developed for three or 12 months under reduced predation (in cages). Cages had a mesh size of 0.635 cm.  Communities were retrieved, assessed for species richness using non-destructive methods, and assigned to control (re-caged) or exposure (no cage) treatments.  Communities were re-deployed in the same location where they developed for a short-term, three-day experiment to test the impact of ambient predation on prey communities. Initial deployment of caged panels occurred in Alaska in June 2015, California in May 2016, Mexico in June 2017 and Panama in December 2015.

Sampling and analytical procedures:

Following the assigned development period, communities were temporarily retrieved and brought back to a laboratory for assessment. Communities were then re-deployed in their original location on the same day, and cages were either removed (exposure treatment) or kept intact (controls) for the short-term three-day experiment. After three days, communities were retrieved again and brought back to a laboratory for final assessment. Initial richness (pre) was assessed using non-destructive methods and is directly comparable with final richness (post1), which was recorded using the same methods.  Additional species not originally recorded were uncovered using destructive methods (post2).  Species richness provided here is a comprehensive list of sessile invertebrate species observed per community, including species that were captured in point count (composition) measures and those that were not.