Modeling the succession of barnacles and mussels on a sandstone reef in Pernambuco State, Brazil

Abstract

Settlement and recruitment rates, biological interactions, environmental parameters, and larval supply are factors that influence community structure in areas where barnacles and mussels are the dominant fauna. This study modeled the succession populations of two barnacle species, Tetraclita stalactifera (Lamarck, 1818) and Chthamalus bisinuatus (Pilsbry, 1916), and a bivalve, Brachidontes solisianus (d'Orbigny, 1846), on a sandstone reef at Piedade Beach, Pernambuco State, Brazil. The different stages of the life cycles of these invertebrates are represented by adult and immature forms in this model and are simulated as numbers of individuals per 100 cm 2 . Recruitment rates are represented as forcing functions based on field recruitment experiments with time-steps of 1 day. In addition to intraspecific competition, the model takes into account interspecific competition based on reciprocal effects and carrying capacities. Field data from field succession experiments were used to calibrate the model. Recruitment and succession data were collected from random 10 9 10-cm plots within a 1-m transect on a Brachidontes bed from April to December 2007. Correlation coefficients between field data and simulation results were statistically significant for both populations; sensitivity analysis showed that increases and decreases in invertebrate population densities were always smaller than 10% compared to baseline model values. Patch closure by mussels population growth was one of the main succession processes observed during the rainy season. However, barnacles were the dominant species at the end of both field and simulation succession experiments, with an average density of close to 100 individuals per 100 cm 2 . Cirripedia individuals may inhibit bivalve re-colonization by settling over shells and more efficiently occupying free space in addition to having higher recruitment rates than bivalves during the dry season.

Recovery Process on Soft-Bottom Macrobenthic Communities after Artificial Disturbance in Tropical Polluted Estuary (Guanabara Bay, Rio de Janeiro, Brazil)

“…The order Amphipoda was the most abundant between the Crustacea, it contributed 92.1% of the total of organisms in the subphylum. The suborder Caprellidea and Cirripedia were excluded from the analyses because of their habits, Caprellidea lives associated with algae, briozoos and ascidian [17,18] and Cirripedia needs a hard surface to settle [19]. The phylum Mollusca was just found in the T2.…”

Modeling temporal variations of Gracilaria Greville and Hypnea J.V. Lamouroux (Rhodophyta) assemblages on a midlittoral reef platform at Piedade Beach, Pernambuco State, Brazil

“…Sensitivity analyses for model outputs were performed using equation (15), varying the initial biomass conditions and each parameter by ±10% to calculate percentage changes in relation to baseline runs (Guimaraens et al 2008(Guimaraens et al , 2011a). …”

“…Models of tropical benthic communities still require greater refi nement, however, especially in terms of parameters such as recruitment and interspecifi c competition (Biber et al 2004) between algae and invertebrates (Vinueza et al 2006, Guimaraens et al 2011a. The model described here considers physiological processes that mimic competitive interactions (Fong et al 1994, 2005 and their effects on temporal variations of Gracilaria and Hypnea assemblages through the use of different nutrient absorption curves (Fong et al 1994, Biber et al 2004) and different photosynthesis rates for these genera.…”

Temporal and Spatial Variation of Benthic Intertidal Community of a Sandstone Reef in Pernambuco Brazil as a Tool to Evaluate Bioinvasion

“…The coastal reefs of the urban Pernambuco regions suffer with algal overgrowth that in intertidal regions compete mainly with mollusks and crustaceans. These algae grow attached to the substrate or as drift in reef pools [1][2][3]. The increase in biomass and cover of substrate is related to the increment in nutrients and available light after the rainy season, with predictable nutrient accumulation in the algal thallus.…”