Advances in coastal ecology: people, processes and ecosystems in Kenya

The coastal population of Sub-Sahara Africa is increasing rapidly but coastal zones are fragile environments that are easily disturbed and easily damaged when overexploited. There is need for carefully thought out management of resources to realize both environmental sustainability and potential socio-economic benefits. This is the fourth volume in a series of conference proceedings on the ecology of the Kenyan Coast, since 1997. These meetings serve as a forum for the exchange of information among scientists, students policy makers, development agency staff and government officers. This volume contains seventeen papers that were presented at the Coastal Ecology Conference in Mombasa in 2006 with sections on fish and fisheries, mangroves, conservation and management, and ecosystems rehabilitation.ASC – Publicaties niet-programma gebonde

Reefs at Risk: A Map-Based Indicator of Threats to the Worlds Coral Reefs

This report presents the first-ever detailed, map-based assessment of potential threats to coral reef ecosystems around the world. "Reefs at Risk" draws on 14 data sets (including maps of land cover, ports, settle-ments, and shipping lanes), information on 800 sites known to be degraded by people, and scientific expertise to model areas where reef degradation is predicted to occur, given existing human pressures on these areas. Results are an indicator of potential threat (risk), not a measure of actual condition. In some places, particularly where good management is practiced, reefs may be at risk but remain relatively healthy. In others, this indicator underestimates the degree to which reefs are threatened and degraded.Our results indicate that:Fifty-eight percent of the world's reefs are poten-tially threatened by human activity -- ranging from coastal development and destructive fishing practices to overexploitation of resources, marine pollution, and runoff from inland deforestation and farming.Coral reefs of Asia (Southeastern); the most species-rich on earth, are the most threatened of any region. More than 80 percent are at risk (undermedium and high potential threat), and over half are at high risk, primarily from coastal development and fishing-related pressures.Overexploitation and coastal development pose the greatest potential threat of the four risk categories considered in this study. Each, individually, affects a third of all reefs.The Pacific, which houses more reef area than any other region, is also the least threatened. About 60 percent of reefs here are at low risk.Outside of the Pacific, 70 percent of all reefs are at risk.At least 11 percent of the world's coral reefs contain high levels of reef fish biodiversity and are under high threat from human activities. These "hot spot" areas include almost all Philippine reefs, and coral communities off the coasts of Asia, the Comoros, and the Lesser Antilles in the Caribbean.Almost half a billion people -- 8 percent of the total global population -- live within 100 kilometers of a coral reef.Globally, more than 400 marine parks, sanctuaries, and reserves (marine protected areas) contain coral reefs. Most of these sites are very small -- more than 150 are under one square kilometer in size. At least 40 countries lack any marine protected areas for conserving their coral reef systems

Mosquito Net Use in an Artisanal East African Fishery

Widespread, anecdotal reports of the use of bed nets designed for malaria control (“mosquito nets”) in artisanal fisheries have led to concern from health and natural resource management sectors. However, mosquito net fishing (MNF) may play an important role in the livelihoods of artisanal fishers, an aspect not yet investigated. At a coastal Kenyan site among Giriama fishers, nearly half of homesteads interviewed used mosquito nets as fishing gear, targeting juvenile fish and prawns for subsistence and sale. The majority of mosquito net (MN) fishers here were men, suggesting that the assumption that MNF is a female activity is not valid in this case. However, MN use for fishing at this site is unlikely to impact malaria protection as fishers used old or surplus nets. Respondents perceived both positive aspects of MNF (e.g., food and income) and negative aspects (e.g., impact on fishery). As mosquito nets are widely available, they may enable new entrants to access fisheries. There is a critical need to review current management responses, which predominately focus on banning the practice, and instead promote integrated strategies for sustainable livelihoods

Mobility, Expansion and Management of a Multi-Species Scuba Diving Fishery in East Africa

Background: Scuba diving fishing, predominantly targeting sea cucumbers, has been documented to occur in an uncontrolled manner in the Western Indian Ocean and in other tropical regions. Although this type of fishing generally indicates a destructive activity, little attention has been directed towards this category of fishery, a major knowledge gap and barrier to management. Methodology and Principal Findings: With the aim to capture geographic scales, fishing processes and social aspects the scuba diving fishery that operate out of Zanzibar was studied using interviews, discussions, participant observations and catch monitoring. The diving fishery was resilient to resource declines and had expanded to new species, new depths and new fishing grounds, sometimes operating approximately 250 km away from Zanzibar at depths down to 50 meters, as a result of depleted easy-access stock. The diving operations were embedded in a regional and global trade network, and its actors operated in a roving manner on multiple spatial levels, taking advantage of unfair patron-client relationships and of the insufficient management in Zanzibar. Conclusions and Significance: This study illustrates that roving dynamics in fisheries, which have been predominantly addressed on a global scale, also take place at a considerably smaller spatial scale. Importantly, while proposed management of the sea cucumber fishery is often generic to a simplified fishery situation, this study illustrates

Effects of management objectives and rules on marine conservation outcomes

Understanding the relative effectiveness and enabling conditions of different area-based management tools is essential for supporting efforts that achieve positive biodiversity outcomes as area-based conservation coverage increases to meet newly set international targets. We used data from a coastal social–ecological monitoring program in 6 Indo-Pacific countries to analyze whether social, ecological, and economic objectives and specific management rules (temporal closures, fishing gear-specific, species-specific restrictions) were associated with coral reef fish biomass above sustainable yield levels across different types of area-based management tools (i.e., comparing those designated as marine protected areas [MPAs] with other types of area-based management). All categories of objectives, multiple combinations of rules, and all types of area-based management had some sites that were able to sustain high levels of reef fish biomass—a key measure for coral reef functioning—compared with reference sites with no area-based management. Yet, the same management types also had sites with low biomass. As governments advance their commitments to the Kunming–Montreal Global Biodiversity Framework and the target to conserve 30% of the planet's land and oceans by 2030, we found that although different types of management can be effective, most of the managed areas in our study regions did not meet criteria for effectiveness. These findings underscore the importance of strong management and governance of managed areas and the need to measure the ecological impact of area-based management rather than counting areas because of their designation

Optimal siting, sizing, and enforcement of marine protected areas

The design of protected areas, whether marine or terrestrial, rarely considers how people respond to the imposition of no-take sites with complete or incomplete enforcement. Consequently, these protected areas may fail to achieve their intended goal. We present and solve a spatial bio-economic model in which a manager chooses the optimal location, size, and enforcement level of a marine protected area (MPA). This manager acts as a Stackelberg leader, and her choices consider villagers’ best response to the MPA in a spatial Nash equilibrium of fishing site and effort decisions. Relevant to lower income country settings but general to other settings, we incorporate limited enforcement budgets, distance costs of traveling to fishing sites, and labor allocation to onshore wage opportunities. The optimal MPA varies markedly across alternative manager goals and budget sizes, but always induce changes in villagers’ decisions as a function of distance, dispersal, and wage. We consider MPA managers with ecological conservation goals and with economic goals, and identify the shortcomings of several common manager decision rules, including those focused on: (1) fishery outcomes rather than broader economic goals, (2) fish stocks at MPA sites rather than across the full marinescape, (3) absolute levels rather than additional values, and (4) costless enforcement. Our results demonstrate that such naïve or overly narrow decision rules can lead to inefficient MPA designs that miss economic and conservation opportunities

Limited Progress in Improving Gender and Geographic Representation in Coral Reef Science

Despite increasing recognition of the need for more diverse and equitable representation in the sciences, it is unclear whether measurable progress has been made. Here, we examine trends in authorship in coral reef science from 1,677 articles published over the past 16 years (2003–2018) and find that while representation of authors that are women (from 18 to 33%) and from non-OECD nations (from 4 to 13%) have increased over time, progress is slow in achieving more equitable representation. For example, at the current rate, it would take over two decades for female representation to reach 50%. Given that there are more coral reef non-OECD countries, at the current rate, truly equitable representation of non-OECD countries would take even longer. OECD nations also continue to dominate authorship contributions in coral reef science (89%), in research conducted in both OECD (63%) and non-OECD nations (68%). We identify systemic issues that remain prevalent in coral reef science (i.e., parachute science, gender bias) that likely contribute to observed trends. We provide recommendations to address systemic biases in research to foster a more inclusive global science community. Adoption of these recommendations will lead to more creative, innovative, and impactful scientific approaches urgently needed for coral reefs and contribute to environmental justice efforts.We acknowledge the contributions of the many unrecognized and undervalued individuals in coral reef research whose efforts have made it possible for the field to progress. These scientists have collected data, translated across languages, coordinated field work, welcomed foreign visitors to their countries, shared ideas, trained and mentored students, become friends, inspired, and built the foundation for the discipline we know today. We acknowledge the work of all coral reef scientists who continue day after day to pursue equity, inclusion, and justice in the field and for their colleagues and themselves.Ye

Social–environmental drivers inform strategic management of coral reefs in the Anthropocene

Without drastic efforts to reduce carbon emissions and mitigate globalized stressors, tropical coral reefs are in jeopardy. Strategic conservation and management requires identification of the environmental and socioeconomic factors driving the persistence of scleractinian coral assemblages—the foundation species of coral reef ecosystems. Here, we compiled coral abundance data from 2,584 Indo-Pacific reefs to evaluate the influence of 21 climate, social and environmental drivers on the ecology of reef coral assemblages. Higher abundances of framework-building corals were typically associated with: weaker thermal disturbances and longer intervals for potential recovery; slower human population growth; reduced access by human settlements and markets; and less nearby agriculture. We therefore propose a framework of three management strategies (protect, recover or transform) by considering: (1) if reefs were above or below a proposed threshold of >10% cover of the coral taxa important for structural complexity and carbonate production; and (2) reef exposure to severe thermal stress during the 2014–2017 global coral bleaching event. Our findings can guide urgent management efforts for coral reefs, by identifying key threats across multiple scales and strategic policy priorities that might sustain a network of functioning reefs in the Indo-Pacific to avoid ecosystem collapse

Recent advances in coastal ecology: studies from Kenya

This collective volume presenting recent environmental research on the Kenya coast contains 27 contributions differing widely in scope. Subjects range from coral reef restoration to butterfly breeding, from river sediments to Kaya forests, and from marine fisheries to elephant management. Following the introduction by Jan Hoorweg and Nyawira Muthiga, the papers are presented in six sections, viz. Coral reefs, intertidal and littoral communities (contributions by Priscillah N. Boera, T.R. McClanahan, S. Manohar, R.M. Mdodo, C.M. Muthama, N. Muthiga, G.A. Mwayuli, D. Obura, J.B. Okeyo-Owuor, M.P. Tole, J.N. Uku, B.C.C. Wangila); Sediments, erosion and pollution (contributions by J.O.Z. Abuodha, P.D. Jungerius, Samuel Maende, T.M. Munyao, Muendo Muthini, Marifa Ali Mwakumanya, Dismas Otieno, M.wakiop. Tole); Marine fisheries (contributions by Bernerd Fulanda, Jan Hoorweg, Edward N. Kimani, Anthony King, T.R. McClanahan, Delphine Malleret-King, S. Mangi, Joseph G. Tunje); Mangroves and terrestrial forests (contributions by Ian Gordon, Francis Karanja Kamau, Koen Maes, A.M. Makee, M.T.E. Mbuvi, K.A. Mwendwa, Mwakiop. Tole); Biodiversity (contributions by T.M. Dzeha, A.N. Githitho, S.M. Halevy, Randal Jeske, Moses Litoroh, W.R.Q. Luke, Z.N. Otieno-Ayayo, W.A. Overholt); Community participation (contributions by Washington O. Ayiemba, H. Becha, I. Gordon, Ted Kombo, M.T.E. Mbuvi, J.M. Maweu, K.A. Mwendwa, Joseph Rasowo). [ASC Leiden abstract]</p

Recent advances in coastal ecology: studies from Kenya

This collective volume presenting recent environmental research on the Kenya coast contains 27 contributions differing widely in scope. Subjects range from coral reef restoration to butterfly breeding, from river sediments to Kaya forests, and from marine fisheries to elephant management. Following the introduction by Jan Hoorweg and Nyawira Muthiga, the papers are presented in six sections, viz. Coral reefs, intertidal and littoral communities (contributions by Priscillah N. Boera, T.R. McClanahan, S. Manohar, R.M. Mdodo, C.M. Muthama, N. Muthiga, G.A. Mwayuli, D. Obura, J.B. Okeyo-Owuor, M.P. Tole, J.N. Uku, B.C.C. Wangila); Sediments, erosion and pollution (contributions by J.O.Z. Abuodha, P.D. Jungerius, Samuel Maende, T.M. Munyao, Muendo Muthini, Marifa Ali Mwakumanya, Dismas Otieno, M.wakiop. Tole); Marine fisheries (contributions by Bernerd Fulanda, Jan Hoorweg, Edward N. Kimani, Anthony King, T.R. McClanahan, Delphine Malleret-King, S. Mangi, Joseph G. Tunje); Mangroves and terrestrial forests (contributions by Ian Gordon, Francis Karanja Kamau, Koen Maes, A.M. Makee, M.T.E. Mbuvi, K.A. Mwendwa, Mwakiop. Tole); Biodiversity (contributions by T.M. Dzeha, A.N. Githitho, S.M. Halevy, Randal Jeske, Moses Litoroh, W.R.Q. Luke, Z.N. Otieno-Ayayo, W.A. Overholt); Community participation (contributions by Washington O. Ayiemba, H. Becha, I. Gordon, Ted Kombo, M.T.E. Mbuvi, J.M. Maweu, K.A. Mwendwa, Joseph Rasowo). [ASC Leiden abstract]ASC – Publicaties niet-programma gebonde