Mind your neighbourhood: Biotic and abiotic factors shaping the small‐scale spatial distribution of sponges (Demospongiae) in tropical urban beaches

Abstract

The distribution and abundance of a species can be determined by the interaction of that species with both the biotic and abiotic characteristics of the environment it inhabits. The Demospongiae Aplysina solangeae, Cladocroce caelum, Desmapsamma anchorata, Dysidea janiae and Tedania ignis are commonly found in urban beaches along the tropical Brazilian coast. They reproduce year round in these localities and are thus good model species candidates for studies of evolutionary developmental biology, ecotoxicology and bioprospecting. Here, we investigate how substrate and community requirements modulate the density of these species in two urban beaches in Todos os Santos Bay, Brazil, in order to better comprehend the species’ needs for settlement and growth. We assessed the density of the target species by sampling quadrats during SCUBA dives at these two beaches. Generalised additive models were used to assess how the per cent coverage of benthic organisms co‐occurring with these species influenced the density of the target species. As expected, we found that each species had different requirements for their spatial distribution, with most species being generalists. The only exception to this was found with C. caelum, which appeared to be more specialist, requiring a higher number of explanatory variables in terms of neighbouring benthos despite being the most abundant target species in both localities. A comparison of the differences observed in small‐scale localities and the regional scale is presented. Our findings on how selective these species are about their “neighbourhood” allow us to better comprehend their life histories and predict their dynamics in a changing environment.

bnormal average increase in sea surface temperature may promote the first documented mortality event of a marine sponge in the Southeastern Brazil

“…This sponge dominates Brazilian tropical bays rocky shores (Muricy and Hajdu 2006;Hajdu et al 2011;Fortunato et al 2020), but it also likes sedimented substrates from the Caribbean Sea to Rio de Janeiro state (McLean and Yoshioka 2008;Hajdu et al 2011;Fortunato et al 2020). In general, few factors directly affect the species density in Brazil, such as presence of a more abundant species in Todos os Santos Bay (Bahia state) (see Oliveira and Lanna 2018) and hydrodynamics in IGB (Rio de Janeiro state) (see Fortunato et al 2020).Specifically to IGB, it is one of the most frequent benthic species throughout the year in both abundance and relative cover in the bay side (Mantelatto et al 2013(Mantelatto et al , 2022Fortunato et al 2020). Their fragments presented fast growth from September to November during a manipulated experiment, doubling their volumes within a month (Ferreira 2016), and it can outgrow the invasive sun corals Tubastraea spp.…”

Anatomy and ultrastructure of the tropical sponge Cladocroce caelum (Haplosclerida, Demospongiae)

“…The sponge C. caelum is quite common in the intertidal and infralittoral of Todos os Santos Bay (Bahia, Brazil), being found close to urban areas (Hajdu, Peixinho, & Fernandez, —identified as Haliclona manglaris ) and is one of the most common sponges in some areas along the Salvador (Bahia State, Brazil) city coastline (Oliveira & Lanna, ). As it is a conspicuous species, we selected C. caelum as a model to carry out investigations through different perspectives aiming to better comprehend the biology and evolution of Porifera, including the aquiferous system organization.…”