PARENT SESSION
Poster Session # 21: Biogeography, Biodiversity, Populations, and Genetics.
Thursday, August 7 Presentation from 5:00 PM to 6:30 PM. SITCC Exhibit Hall B.
Metacommunity dynamics drive rockpool community recovery after a natural disturbance.
Chapman, Carol*,1, Jenkins, David1, 1 University of Illinois at Springfield, Springfield, IL
ABSTRACT- Rock pool communities at Discovery Bay Marine Lab (Jamaica) provide a valuable system of natural microcosms in which metacommunity concepts can be tested in a complex landscape. Following a storm surge that flushed pools with seawater, we sampled 52 pools (by mixing and subsampling) and 34 outflows (by nets in overflows) to measure metacommunity dynamics in 15 watersheds, then compared the results to ten years of pool data. We also sampled vertical distributions in pools at night and midday to determine if vertical migration affected dispersal. We hypothesized that: pool communities would be strongly altered by the seawater flush; communities would recover to historical composition over time; and dispersal within watershed metacommunities would drive subsequent community structure. Freshwater communities were more severely affected by seawater flush than brackish or saline pools. Pools with higher organic matter inputs (mangrove litter or autochthonous inputs) rapidly produced abundant copepod nauplii, which dispersed in rainfall overflows into downstream pools. Other organisms (e.g., ostracods, harpacticoid and cyclopoid copepods, insect larvae, turbellarians, and nematodes) also dispersed. Crab zoea (Sesarma miersi) were collected in mid- to surface samples at night, but were not in the water column during days. Crab zoea do not disperse as readily as other species in overflows, and may be preying on species that disperse more readily. Therefore, prey dispersal may subsidize predator populations in some pools, and community composition is strongly affected by dispersal after a disturbance. Rockpool communities are easily observed microcosms that enable the testing of theoretical metacommunity concepts outside of the lab.
Key words: dispersal, disturbance, metacommunity dynamics, rockpool microcosms