UC San Diego

My dissertation explores ecosystem services through different time and spatial scales in coastal wetlands of Northwest México. This region of Mexico is currently being subject to radical changes in socioeconomic and environmental issues caused by an increased demand for agricultural and fishing resources. The high demand for natural resources in the region is linked to economic development policies, which promote the exploitation of natural resources. For this reason understanding ecosystem services through different temporal and spatial scales is a necessity for the future welfare of coastal communities and sustainable use of natural resources. Throughout my dissertation I collected interdisciplinary data related to historical ecology, ecology, social sciences and economics to assess the role and importance of coastal ecosystem services. Chapter I focuses on analyzing data from diverse disciplines (e.g. history, archaeology, ecology and current local-ecological knowledge of fishers) to document the history of fisheries exploitation in the Marismas Nacionales, the largest northern mangrove area on the Pacific coast of North America. This approach is necessary in order to understand the current status of fisheries in a region. Here I explored fisheries since Pre-Columbian times to the present. I show the Marismas Nacionales fishery resources and inshore fishing areas have dramatically changed mostly by the excessive fishing effort of the past century. The reduced inshore fishery resources and the increasing fishers population initiated a race to fish and has promoted the use of unsustainable fishing practices among modern fishers. Modern catches show a reduce fish diversity, and lower trophic level fish are today's main catches. Chapter II analyses the current fishery services of seven lagoon-estuarine complexes (LECs) in Northwest Mexico. I show that even though there is a high diversity of species groups found in the LECs fisheries, only a handful have high fishing selectivity and profitability. I also show the area of the LEC is important for fisheries production and that there is a latitudinal gradient for species groups caught in LECs. This information can be used to provide a better understanding of the dynamics of LECs fisheries in Northwest Mexico. Finally, Chapter III analyzes the transnational ecosystem services provided coastal lagoons of Northwest Mexico, as demonstrated by their role for wintering habitat for waterfowl in the Pacific Flyway. This waterfowl are part of a very profitable hunting industry in the United States and Canada. I show that the number of waterfowl harvested in the US is related to the abundance of waterfowl wintering in Mexico. On average, this flow of ecosystem services annually yields US$ 4.68 million in hunting stamp sales in the western US. Besides I estimated a US$ 3-6 million in consumer surplus produced in addition to governmental stamp sales revenues. My results strongly suggests that waterfowl wintering habitat in western Mexico is economically valuable to US hunters. Because hunters may benefit substantially from these habitats they may be willing to pay for conservation efforts in western Mexico that can result in transnational benefits received in the US. Overall my research provides unique insights on how ecosystem services of coastal wetlands have historically provided subsistence and direct and indirect economic benefits to humans inhabiting nearby and faraway from these ecosystems. Finally my results also emphasize the importance of considering both the social and ecological systems in future management and conservation actions in order to improve the quality and production of ecosystem services provided by coastal wetlands in Northwest Mexico