The impact of coastal urbanization on the structure of phytobenthic communities in southern Brazil Cintia D.L. Martins a,⇑ , Noele Arantes a , Caroline Faveri a , Manuela B. Batista a , Eurico C. Oliveira b , Paulo R. Pagliosa c , Alessandra L. Fonseca c , José Marcos C. Nunes d , Fungyi Chow b , Sonia B. Pereira e , Paulo A. Horta a a Department of Botany, Universidade Federal de Santa Catarina, 88040-900 Florianópolis, Brazil b Department of Botany, Universidade de São Paulo, São Paulo, Brazil c Department of Geoscience, Universidade Federal de Santa Catarina, Florianópolis, Brazil d Department of Botany, Universidade Federal da Bahia, Salvador, Brazil e Department of Biology, Universidade Federal Rural de Pernambuco, Recife, Brazil article info Keywords: Macroalgae Rocky shore Human impact Sewage impact abstract The anthropogenic pressures on coastal areas represent important factors affecting local, regional, and even global patterns of distribution and abundance of benthic organisms. This report undertakes a com- parative analysis of the community structure of rocky shore intertidal phytobenthos in both pristine like environments (PLE) and urbanized environments (UBE) in southern Brazil, characterizing variations on different spatial scales. Multivariate analysis of variance indicated that the PLE is characterized by a lar- ger number of taxa and an increased occurrence of Rhodophyta species in relation to UBE. In contrast, UBE were dominated by opportunistic algae, such as Cladophora and Ulva spp. Significance tests further indicated higher species richness and Shannon–Wiener diversity on the PLE in relation to UBE. Here we provide data showing the magnitude of seaweed biodiversity loss and discuss direct and indirect conse- quences of unplanned urbanization on these communities. Ó 2012 Elsevier Ltd. All rights reserved. 1. Introduction Although the patterns of distribution and abundance of marine biota are known and reasonably foreseeable at different scales (Lüning, 1990), the increasing human ecological footprint on coast- al ecosystems may profoundly change the local, regional, and even global structure of these communities. Such pressures were high- lighted recently with the decline of phytoplankton on a global scale, mainly in tropical and subtropical regions, which, among other reasons, were attributed to coastal processes such as the in- put of continental effluents (Boyce et al., 2010). At the end of the last century, coastal population was approximately 3.6 billion peo- ple living no more than 100 km from the coastline (Vitousek et al., 1997). This has resulted in a pattern of irregular and disordered occupation which exerts even greater stresses on the coastal eco- system. In the developing and underdeveloped countries this real- ity is even more striking, with occupancy rates larger than those observed in developed countries. Since most of these impacted regions are located in the southern hemisphere, this scenario is particularly worrisome because survival of the local population depends, either directly or indirectly, on the services and products provided by these ecosystems. This is aggravated by deforestation, combined with the release of domestic sewage in natura, which increases the degradation potential on coastal environments. Organic and inorganic pollutants, nutrients, turbidity, suspended solids in excess, and habitat changes, including hydrological regime, are examples of stressors that may impact the biota, singly or in combination, including synergistic effects (Adams, 2005). Anthropogenic stressors promote a particular impact on benthic communities, which are often structured by sessile organisms such as seaweeds. As seen in other regions, such impacts can result in the reduction of species number and abundance of primary pro- ducers, with consequent simplification of community structure. This, in turn, leads to an eventual increase in the abundance of opportunistic taxa with high reproductive capacity and tolerance against pollution. By integrating the effects of prolonged exposure to adverse conditions, the rocky shore seaweeds can be considered good indicators of environmental changes caused by different types of disturbances (Gorostiaga and Díez, 1996). The potential application of these organisms as bioindicators is even greater be- cause they are widely and easily found in intertidal regions, which frequently represent the entry point of continental effluents. Stud- ies using seaweeds as a means of diagnosing the degradation of coastal environments have been conducted mostly in the northern 0025-326X/$ - see front matter Ó 2012 Elsevier Ltd. All rights reserved. doi:10.1016/j.marpolbul.2012.01.031 ⇑ Corresponding author. Tel.: +55 21 48 37218541. E-mail address: cintia_ufpr@yahoo.com.br (C.D.L. Martins). Marine Pollution Bulletin 64 (2012) 772–778 Contents lists available at SciVerse ScienceDirect Marine Pollution Bulletin journal homepage: www.elsevier.com/locate/marpolbul