Collaborative Research: Response of Tropical Stream Ecosystem Structure and Function to Amphibian Extinctions

抽象的。 两栖动物代表了水生和陆生栖息地之间的重要能量联系，特别是在热带地区，那里的多样性和丰度非常高。 蝌蚪以藻类和有机物质为食，当它们变成青蛙时，将能量和营养从水生栖息地转移到陆地栖息地，而青蛙在返回水中繁殖时将能量和物质转移回来。 然而，世界各地的两栖动物数量急剧下降，包括过去20年中13个拉丁美洲国家的大规模损失。 大多数物种的减少都涉及到某一特定地点超过75%的两栖动物的消失。 这项研究将通过调查损失如何改变河流生物多样性，河流中的能量流动，河流和河边食物网以及河流和陆地栖息地之间的能量交换来研究两栖动物减少对热带河流的影响。 这将通过流社区，食物网，和能量流模式在巴拿马高原流与自然两栖动物种群和附近的流两栖动物最近消失的密集比较。 初步研究表明，两栖动物的减少将对溪流产生大规模的影响，包括群落结构的变化，藻类能源的重要性增加，有机物质的下游运输减少，以及从溪流到陆地生境的能量转移减少。更广泛的影响。 这项研究的更广泛的意义是，研究结果将与影响许多地区的紧迫问题（即两栖动物减少）有关。拟议的研究还将为来自拉丁美洲和美国的学生提供机会，研究一个重要的大规模环境问题，并将进一步加强三个相关机构与其他研究热带地区相关问题的科学家之间的合作。

Abstract. Amphibians represent an important energetic link between aquatic and terrestrial habitats, particularly in the tropics where diversity and abundance are very high. Tadpoles feed on algae and organic materials and transfer energy and nutrients from aquatic to terrestrial habitats when they emerge as frogs, and frogs transfer energy and materials back when they return to water to breed. However, amphibian populations have declined dramatically around the world, including massive losses in 13 Latin American countries in the last 20 years. Most declines involve disappearances of over 75% of amphibians at a given site. This research will examine the consequences of amphibian declines on tropical streams by investigating how losses alter stream biodiversity, energy flow in streams, in-stream and streamside food webs, and energy exchange between streams and terrestrial habitats. This will be accomplished through intensive comparisons of stream communities, food webs, and energy flow patterns in Panamanian highland streams with natural amphibian populations and nearby streams where amphibians have recently disappeared. Preliminary studies suggest that amphibian declines will have large-scale effects on streams, including changes in community structure, shifts to increased importance of algal energy sources, reduced downstream transport of organic materials, and reduced energy transfer from streams to terrestrial habitats. Broader impacts. The broader implications of this research are that findings will be relevant to an urgent problem (i.e. amphibian declines) influencing many regions. The proposed research will also provide opportunities for students from Latin America and the U.S. to work on an important, large-scale environmental issue and will further collaboration between the 3 institutions involved and other scientists researching related issues in the tropics.