Natural drivers of distribution of ghost crabs Ocypode quadrata and the implications of estimates from burrows

Abstract

MEPS Marine Ecology Progress Series Contact the journal Facebook Twitter RSS Mailing List Subscribe to our mailing list via Mailchimp HomeLatest VolumeAbout the JournalEditorsTheme Sections MEPS 565:131-147 (2017) - DOI: https://doi.org/10.3354/meps11991 Natural drivers of distribution of ghost crabs Ocypode quadrata and the implications of estimates from burrows Maíra Pombo*, Andréa Lima de Oliveira, Luciana Yokoyama Xavier, Eduardo Siegle, Alexander Turra Instituto Oceanográfico da Universidade de São Paulo, Praça do Oceanográfico 191, 05508-120, São Paulo, Brazil *Corresponding author: mairapombo@gmail.com ABSTRACT: Ghost crabs are important sandy beach dwellers whose bioindicator potential depends on a broader understanding of the relationship between environmental and biological parameters. We analyzed variations in ghost crab populations both directly (abundance, size, and sex ratio) and indirectly (burrow occupation rate and size differences between crabs and burrows) in relation to their across-shore distribution and their relationship with beach features. Nine pristine areas with distinct morphodynamics and wave exposure levels were sampled quarterly over 1 yr. Across-shore variability was recorded with larger crab sizes, lower occupation rates, and proportionally more females landwards. Storm surge period was a determining factor with respect to ghost crab populations, causing individuals to contract their distribution landwards and increases in burrow occupation rate and mean crab size estimates. Beach features influenced population parameters, with crab density and mean size tending to increase towards smaller grain sizes and with steeper slopes in the crab’s range of occurrence favoring crab abundance. Burrow occupation rate differed according to slope and crab density. Our results revealed an intrinsic variability of ghost crab populations over time and among and within beaches that may be a source of bias in environmental studies. Therefore, these phenomena should be considered in the design of monitoring strategies and impact assessment protocols. This study also emphasizes the need for a cautionary approach in data interpretation of crab number and size based on burrow estimates. KEY WORDS: Morphodynamics · Wave exposure · Abundance · Size · Indicator species ·Monitoring Full text in pdf format Supplementary material PreviousNextCite this article as: Pombo M, Oliveira AL, Xavier LY, Siegle E, Turra A (2017) Natural drivers of distribution of ghost crabs Ocypode quadrata and the implications of estimates from burrows. Mar Ecol Prog Ser 565:131-147. https://doi.org/10.3354/meps11991 Export citation RSS - Facebook - Tweet - linkedIn Cited by Published in MEPS Vol. 565. Online publication date: February 17, 2017 Print ISSN: 0171-8630; Online ISSN: 1616-1599 Copyright © 2017 Inter-Research.