Wicked social–ecological problems forcing unprecedented change on the latitudinal margins of coral reefs: the case of southwest Madagascar

High-latitude coral reefs may be a refuge and area of reef expansion under climate change. As these locations are expected to become dryer and as livestock and agricultural yields decline, coastal populations may become increasingly dependent on marine resources. To evaluate this social–ecological conundrum, we examined the Grand Récif of Toliara (GRT), southwest Madagascar, which was intensively studied in the 1960s and has been highly degraded since the 1980s. We analyzed the social and ecological published and unpublished literature on this region and provide new data to assess the magnitude of the changes and evaluate the causes of reef degradation. Top-down controls were identified as the major drivers: human population growth and migrations, overfishing, and climate change, specifically decreased rainfall and rising temperature. Water quality has not changed since originally studied, and bottom-up control was ruled out. The identified network of social–ecological processes acting at different scales implies that decision makers will face complex problems that are linked to broader social, economic, and policy issues. This characterizes wicked problems, which are often dealt with by partial solutions that are exploratory and include inputs from various stakeholders along with information sharing, knowledge synthesis, and trust building. A hybrid approach based on classical fishery management options and preferences, along with monitoring, feedback and forums for searching solutions, could move the process of adaptation forward once an adaptive and appropriately scaled governance system is functioning. This approach has broad implications for resources management given the emerging climate change and multiple social and environmental stresses

Wicked social-ecological problems forcing unprecedented change on the latitudinal margins of coral reefs: the case of southwest Madagascar

High-latitude coral reefs may be a refuge and area of reef expansion under climate change. As these locations are expected to become dryer and as livestock and agricultural yields decline, coastal populations may become increasingly dependent on marine resources. To evaluate this social-ecological conundrum, we examined the Grand Récif of Toliara (GRT), southwest Madagascar, which was intensively studied in the 1960s and has been highly degraded since the 1980s. We analyzed the social and ecological published and unpublished literature on this region and provide new data to assess the magnitude of the changes and evaluate the causes of reef degradation. Top-down controls were identified as the major drivers: human population growth and migrations, overfishing, and climate change, specifically decreased rainfall and rising temperature. Water quality has not changed since originally studied, and bottom-up control was ruled out. The identified network of social-ecological processes acting at different scales implies that decision makers will face complex problems that are linked to broader social, economic, and policy issues. This characterizes wicked problems, which are often dealt with by partial solutions that are exploratory and include inputs from various stakeholders along with information sharing, knowledge synthesis, and trust building. A hybrid approach based on classical fishery management options and preferences, along with monitoring, feedback and forums for searching solutions, could move the process of adaptation forward once an adaptive and appropriately scaled governance system is functioning. This approach has broad implications for resources management given the emerging climate change and multiple social and environmental stresses

Lobophora (Dictyotales, Phaeophyceae) from the western Indian Ocean: diversity and biogeography

The brown algal genus Lobophora (Dictyotales, Phaeophyceae) is an important ecological component of tropical marine systems. Although still scantily sampled, 35 species of Lobophora were discovered previously from the western Indian Ocean. This study updates previous diversity estimates by incorporating recent collections from Madagascar, Mozambique, and the Red Sea, considerably improving our knowledge of Lobophora diversity and biogeography in this region. Eight additional species are identified from the western Indian Ocean, raising the total number of Lobophora species to 43. Fifteen species are new to science and described herein. With ca. 40% of the global diversity, the western Indian Ocean is second only to the Central IndoPacific. Of the species identified to date, 29 appear to be restricted to the western Indian Ocean, three are shared with the Atlantic (four including L. lessepsiana introduced to the western Mediterranean Sea) and 12 have a wider distribution in the Indo-Pacific. The western Indian Ocean supports a high diversity with ca. 67% of its Lobophora restricted to this region, which is comparable to the Central Indo-Pacific (62%) and the Caribbean (61%). The presence of several putative endemic species in the western Indian Ocean islands and the Red Sea illustrates that these provinces played an important role in Lobophora species diversification within the western Indian Ocean by producing locally new species. The small number of species shared between the western Indo-Pacific and Atlantic indicates that this oceanic boundary - associated with the temperate Agulhas marine province, and the Benguela current and upwelling - acts as an effective dispersal barrier.info:eu-repo/semantics/publishedVersio

HILOI, a research program on seagrass ecosystems in islands from the Western Indian Ocean

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