Effects of short-term rain events on mobile macrofauna living on seawalls

Abstract

2007). Effects of shortterm rain events on mobile macrofauna living on seawalls.The distribution and abundance of intertidal organisms can be affected by short-term events, such as rain. We compared the effects of rain on intertidal mobile invertebrates in four common microhabitats with differing amounts of shelter (namely beds of oysters, coralline turf, bare patches and crevices) on sea walls in Sydney Harbour. There was an effect of rain on some, but not all taxa, although this was not consistent between locations or times. Effects of rain were observed for some species of gastropods and crustaceans, but not for polychaetes. Manipulative experiments using artificial rain indicated that rain, without the presence of run-off and independent of potential temporal confounding from differences in weather conditions, has a negative effect on abundances of amphipods in coralline turf. Pulse responses by mobile organisms to short-term rain events should be considered when designing experiments looking at temporal variability and processes responsible for observed patterns of distribution of marine organisms.

Complexity of the prey spectrum ofAgaronia propatula(Caenogastropoda: Olividae), a dominant predator in sandy beach ecosystems of Pacific Central America

“…Much of the Pacific Central American coast experiences a pronounced contrast between a rainy and a dry season. Frequent torrential rains during the wet season could certainly induce severe hypo-osmotic stress for any osmo-conforming invertebrate that utilizes the intertidal zone at intermediate and low tide (for studies of the effect in other taxa, see Blockley et al, 2007 ; Morritt et al, 2007 ; Montory et al, 2014 ). Mazatlania fulgurata , a columbellid gastropod that shares the habitat with A. propatula , reproduces primarily in the dry season, which probably reduces the chance of exposure of eggs and larvae to hypo-osmotic stress (D. Stevenson & W. S. Peters, 2012–2018, unpublished data).…”

Echinoderms in San Matías Gulf, Southwestern Atlantic Ocean

“…Global biodiversity is under increasing pressure from environmental variation threatened by anthropogenic global climate change (Harley et al 2006;Wernberg et al 2011) which affects large-scale oceanographic variables such as pH, salinity, and sea surface temperature (Harley et al 2006). Responses of organisms to a gradual climate change are expressed in the latitudinal modification in species abundance and migration of biogeographic boundaries (Barry et al 1995;Blockley et al 2007;Harley 2011). Understanding species variation allows identifying the importance of environmental controls on population structure and anticipates potential consequences of regional changes on local populations (Helmuth et al 2006).…”