Neotropical coastal lagoons: an appraisal of their biodiversity, functioning, threats and conservation management

Abstract

Neotropical coastal lagoons (NCL) are human-dominated ecosystems. Their distribution along densely populated coastal areas of developing countries makes these systems among the most threatened in the world. Here, we summarize some aspects of the causes and consequences of NCL biodiversity, their functioning, their importance to the surrounding populations, their fragility, and their responses to local and global anthropogenic impacts and the challenges that Neotropical countries face in conserving these systems. Although still scarce and geographically concentrated, a growing body of studies has shown that NCLs are physiographically diversified systems, which harbor a considerable and particular proportion of the Neotropical inland aquatic biodiversity. Despite the fact that coastal lagoons are ecotones that are intricately connected to surrounding environments, they develop mechanisms for structural and functional regulation, which confer to these systems higher productivity and carrying capacities than surrounding ecosystems. Such traits attract residential developments and subsidize local traditional populations with important economic and aesthetic ecosystem revenues such as fisheries and scenic beauty. However, the disorganized human occupation around NCLs are causing profound impacts such as eutrophication, salinization, exotic species introduction, as well as other effects, which are ultimately imposing major habitat degradations and biodiversity extirpations in NCLs. We argue that interdisciplinary conservation strategies, which integrate scientific expertise, government officials, private companies and the general public, are the most likely to overcome the geographic and economic obstacles to NCL conservation.Keywords: coastal ecosystems, ecosystem management, shallow lakes, human impacts, tropical limnology.Lagoas costeiras neotropicais: Uma apreciação sobre sua biodiversidade, funcionamento, principais ameaças e estratégias de conservação ResumoAs lagoas costeiras neotropicais (LCN) estão inseridas em um ambiente antropogênico. Sua localização em regiões costeiras densamente povoadas de países em desenvolvimento coloca estes ecossistemas entre os mais impactados do mundo. Neste trabalho, resumimos vários aspectos relacionados às causas e conseqüências da sua biodiversidade, seu funcionamento e os bens proporcionados à população do seu entorno. Sua fragilidade e as respostas a impactos humanos locais e globais, assim como os desafios para a sua conservação por países neotropicais, também são abordados. Apesar de escassos e geograficamente concentrados, um número crescente de estudos tem mostrado que as LCN são sistemas fisiograficamente diversificados, abrigando uma proporção considerável da biodiversidade dos ambientes aquáticos continentais neotropicais. Apesar de as lagoas costeiras representarem ecótonos bastante conectados ao ambiente adjacente, elas desenvolveram mecanismos próprios de regulação funcional e estrutural, conferindo uma maior produtividade e capacidade de suporte em relação...

Temporal coherence among tropical coastal lagoons: a search for patterns and mechanisms

“…A great number of coastal lagoons might occur within a relatively small area, which guarantees a greater similarity in their respective exposition to broad-scale regional factors such as climate, surrounding edaphic conditions and sea proximity. On the other hand, coastal lagoons are physiographically diversified systems, ranging in a variety of sizes, morphometries, water chemistry characteristics, landscape positions and trophic status (reviewed in Esteves et al, 2008). For instance, hypersaline and freshwater lagoons can be found side-by-side depending on the relative strength of the particular drivers of their hydrological balance, such as local precipitation, watershed inflow, evaporation and intrusion of seawater by percolation through or overtop the sand barrier (Kjerfve, 1994).…”

Bird diversity and conservation in the southern coast of Santa Catarina state, Brazil

“…Coastal lagoons and their surrounding environments frequently form complex mosaics of aquatic and terrestrial ecossystems that harbor high biodiversity (Esteves et al, 2008). The high productivity of such wetlands provides essencial ecosystemic services to humankind such as water supply and fishing resources (Esteves et al, 2008).…”

“…The high productivity of such wetlands provides essencial ecosystemic services to humankind such as water supply and fishing resources (Esteves et al, 2008). One of the largest complex of lagoons in the Neotropical region is found in the southern coast of Brazil, ranging from southern Santa Catarina state to southern Rio Grande do Sul state (Burger, 1999).…”

Living benthic Foraminifera from the Saquarema lagoonal system (Rio de Janeiro, southeastern Brazil)

“…These environments occupy 13% of coastal areas in the world (Barnes 1980) and support a range of highly valued ecological services (Anthony et al 2009). In addition, transitional environments are among the most biologically productive environments of our planet and harbor a rich and unique biodiversity (Esteves et al 2008;Whitfield et al 2008).…”

“…Climate change, in addition to anthropogenic pertubations such as artificial opening of sandbars and building of drainage canals, can promote, for instance, drying and salinization (Esteves et al 2008). Gomez Gesteira (2003) characterizes water residence time as an important physical variable in estuaries and coastal lagoons and a useful tool for studying the quality of its waters.…”