Effects of human trampling on a rocky shore fauna on the Sao Paulo coast, southeastern Brazil

Abstract

Increased tourist activity in coastal regions demands management strategies to reduce impacts on rocky shores. The highly populated coastal areas in southeastern Brazil are an example of degradation caused by development of industry and tourism. Among different shore impacts, trampling has been intensively studied, and may represent a significant source of stress for intertidal fauna. A randomised blocks design was applied to experimentally study the effects of two different trampling intensities on richness, diversity, density and biomass of the rocky shore fauna of Obuseiro beach, Guarujá, southeastern Brazil. Blocks were distributed in two portions of the intertidal zone, dominated respectively by Chthamalus bisinuatus (Cirripedia) and Isognomon bicolor (Bivalvia). Blocks were trampled over three months, simulating the vacation period in Brazil and were monitored for the following nine months. Results indicate that Chthamalus bisinuatus is vulnerable to trampling impacts. Richness, diversity and turn-over index tended to be higher in trampled plots four months after trampling ceased. In general, results agree with previous trampling studies, suggesting that even low intensities of trampling may cause some impact on intertidal communities. Management strategies should include isolation of sensitive areas, construction of boardwalks, visitor education and monitoring programmes. In Brazil, additional data obtained from experimental studies are necessary in order to achieve a better understanding of trampling impacts on rocky shore communities.Keywords: rocky shore, intertidal community, trampling, tourism impacts.Impactos do pisoteio humano na fauna de um costão rochoso do litoral de São Paulo, no sudeste brasileiro ResumoO aumento da atividade turística em áreas costeiras nas últimas décadas faz necessária a adoção de estratégias de manejo para reduzir os impactos gerados às comunidades de costões rochosos. A região costeira do sudeste brasileiro possui bons exemplos de degradação causada pelo turismo e desenvolvimento industrial. Dentre os diferentes distúr-bios causados pela visitação, o pisoteio têm sido estudado de forma intensa e pode representar uma fonte significativa de impactos para as comunidades da zona entre-marés. Neste projeto, foi aplicado um desenho de blocos randômicos para se avaliar experimentalmente os efeitos de duas intensidades de pisoteio na riqueza, diversidade, densidade, recobrimento e biomassa da fauna de um costão situado na praia do Obuseiro, no município do Guarujá, São Paulo, Brasil.

Abundance of biofilm on intertidal rocky shores: Can trampling by humans be a negative influence?

“…Trampling can negatively affect both the density and biomass of assemblages of organisms in sandy beaches (Veloso et al, 2006;Coombes et al, 2008;Lucrezi et al, 2009aLucrezi et al, , 2009b, salt marshes (Martone and Wasson, 2008), mudflats (Rossi et al, 2007) and rocky shores (Smith and Murray, 2005;Ferreira and Rosso, 2009). Thus it is important to quantify the impacts of trampling for better management and conservation of coastal areas that are subjected to frequent human activity (see reviews by Davenport and Davenport, 2006;Defeo et al, 2009).…”

Previous disturbance enhances the negative effects of trampling on barnacles

“…re cruits or seedlings) may be more susceptible to trampling damage, especially in monospecific stands and areas dominated by a few species. Tests of this third mechanism are lacking.Barnacles represent one of the best studied taxa with respect to trampling (Zedler 1978, Beauchamp & Gowing 1982, Povey & Keough 1991, Brosnan 1994, Jenkins et al 2002, Ferreira & Rosso 2009). However, previous barnacle trampling studies ignored other important disturbances (e.g.…”

“…Studying trampling in isolation from other disturbances may have created some of the uncertainty associated with the influence of trampling on barnacles. For example, footsteps can lower barnacle survivorship (Povey & Keough 1991) and trampling additions can reduce barnacle cover (Brosnan 1994, Ferreira & Rosso 2009. However, several studies found no effect of trampling on barnacle cover (Jenkins et al 2002) or density (Beauchamp & Gowing 1982, Goldstein 1992.…”

An Analysis of Human Disturbance to Rocky Intertidal Communities of San Luis Obispo County

“…Visitor density estimates were made by obtaining: visitation rates based on timed visitor counts, the area of the habitat exposed at the desired tide level, and determining the annual hours of rocky intertidal exposure. In contrast, it may be more difficult to manage the impacts of foot traffic using information from studies incorporating foot step density as the experimental metric (Povey and Keough 1991, Keough and Quinn 1998, Ferreira and Rosso 2009, Huff 2011, for which a scale of footsteps per person would have to be calculated and, which to date, has not been calculated. For this reason, the visitor density metric and calculation methods presented here may be more valuable to resource managers addressing impacts to rocky intertidal communities than metrics used in previous studies.…”

“…While this comprehensive approach was to provide greater support for park management decisions on resource protection, it was also designed and executed to overcome some of the shortcomings of previous studies of human disturbance in natural areas that have been the subject of considerable previous research (e.g., Chan 1970, Underwood and Kennelly 1990, Keough and Quinn 1998, Schiel and Taylor 1999, Murray et al 1999, Ambrose and Smith 2004, Van De Werfhorst and Pearse 2007 (Chan 1970, Ferreira and Rosso 2009. Changes in species abundance levels and distribution can also result from illegal collecting and from trampling.…”