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

抽象的。两栖动物是水生和陆地栖息地之间重要的能量纽带，特别是在多样性和丰度非常高的热带地区。蝌蚪以藻类和有机物质为食，当它们以青蛙的形式出现时，会将能量和营养从水生栖息地转移到陆地栖息地，青蛙在返回水域繁殖时会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，包括在过去20年中13个拉丁美洲国家的大规模损失。大多数下降涉及在给定地点超过75%的两栖动物失踪。这项研究将通过调查损失如何改变河流生物多样性、溪流中的能量流动、溪流中和溪边的食物网以及溪流和陆地栖息地之间的能量交换，来研究两栖动物数量减少对热带河流的影响。这将通过对巴拿马高原溪流与自然两栖动物种群以及最近两栖动物消失的附近溪流的溪流群落、食物网和能量流动模式进行深入比较来实现。初步研究表明，两栖动物的减少将对溪流产生大规模影响，包括群落结构的变化、藻类能源的重要性增加、有机物质下游运输减少以及从溪流到陆地栖息地的能量转移减少。更广泛的影响。这项研究的更广泛影响是，研究结果将与影响许多地区的一个紧迫问题(即两栖动物数量减少)相关。这项拟议的研究还将为来自拉丁美洲和美国的学生提供研究一个重要的大规模环境问题的机会，并将进一步促进参与研究的三个机构与其他研究热带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.