US-Mexico Dissertation Enhancement: Changes in Community Structure and Ecosystem Processes in Response to Armored Catfish Invasion

尽管全球各地都引入了入侵的放牧生物，但对外来食草动物对养分循环和其他关键生态系统过程的影响知之甚少。这一博士论文增强项目的主要目标是研究外来装甲叉尾鱼是否改变了营养循环和初级生产力，降低了本土物种的食物质量和数量，并减少了入侵热带生态系统中无脊椎动物和鱼类的本土生物多样性。研究生Krista Capps将在Alexander Flecker博士的指导下，研究装甲鲶鱼对格里贾尔瓦-乌苏马辛塔分水岭河流系统的影响，格里贾尔瓦-乌苏马辛塔分水岭是墨西哥南部一个生物和文化多样化的地区。这项研究将与墨西哥圣克里斯托瓦尔-拉斯卡萨斯南方学院(ECOSUR)的Rocío Rodiles-Hernández博士合作完成。这项研究产生的成果将包括：1)评估入侵放牧生物影响的实验框架；2)了解外来装甲叉尾鱼如何保留和处理营养物质；3)装甲叉尾鱼入侵地点的生物和化学调查；4)通过建立和加强生物收藏品，加强格里贾尔瓦-乌苏马辛塔分水岭的生物多样性知识。这项研究将直接有助于全面了解外来放牧生物及其对生态系统健康的影响。由于装甲叉尾鱼的入侵与乌苏马辛塔流域地区淡水渔业的崩溃有关，这项研究得出的知识也将对管理产生广泛的影响。研究小组将与墨西哥国家人类学和历史研究所合作，促进对外来装甲叉尾鱼种群的管理，并将加强联合国教科文组织世界遗产帕伦克国家公园及其周围淡水生物的生物多样性知识。

Although invasive grazing organisms have been introduced throughout the globe, little is understood about the effects of exotic grazers on nutrient cycling and other key ecosystem processes. The major objectives of this doctoral dissertation enhancement project are to examine whether exotic armored catfish alter nutrient cycling and primary productivity, decrease food quality and quantity for native species, and reduce native biodiversity of invertebrates and fishes in invaded tropical ecosystems. Graduate student Krista Capps, under the mentorship of Dr. Alexander Flecker, will study the impacts of armored catfishes on rivers systems in the Grijalva-Usumacinta watershed, a biologically and culturally diverse region in southern Mexico. The research will be done in collaboration with Dr. Rocío Rodiles-Hernández of the Colegio de la Frontera Sur (ECOSUR) in San Cristobal de las Casas, Mexico. The products generated by this study will include: 1) an experimental framework to assess the effects of invasive grazing organisms, 2) an understanding of how exotic armored catfish retain and process nutrients, 3) biological and chemical surveys of armored catfish invasion sites, and 4) enhanced biodiversity knowledge of the Grijalva-Usumacinta watershed through the creation and enhancement of biological collections.The introduction of non-native species is one of the greatest threats to species diversity and ecosystem function throughout the world. This study will directly contribute to the general understanding of exotic grazing organisms and their effects on ecosystem health. Since armored catfish invasion has been linked to the collapse of freshwater fisheries in the Usumacinta watershed region, knowledge derived from this study will also have extensive management implications. The research team will collaborate with the Mexican National Institute of Anthropology and History to promote management of exotic armored catfish populations, and will enhance the biodiversity knowledge of freshwater organisms in and around Palenque National Park, a UNESCO World Heritage Site.