DISSERTATION RESEARCH: Testing carbon limitation of cave stream ecosystems via a whole-reach detritus addition

论文研究：通过全范围碎屑添加测试洞穴溪流生态系统的碳限制

• 批准号: 1011403
• 负责人: Jonathan Benstead
• 金额: $ 1.49万
• 依托单位: University of Alabama Tuscaloosa
• 依托单位国家: 美国
• 项目类别: Standard Grant
• 财政年份: 2010
• 资助国家: 美国
• 起止时间: 2010-09-01 至 2012-08-31
• 项目状态: 已结题
• 来源: https://www.nsf.gov/awardsearch/showAward?AWD_ID=1011403&HistoricalAwards=false
• 关键词: DISSERTATION; RESEARCH; Testing; carbon; limitation

The overall goal of this study is to determine whether the availability of energy limits biological activity in cave stream ecosystems. In cave ecosystems, the resource at the base of the food web, and thus the resource that potentially controls overall biological activity, is dead organic matter (e.g. dead leaves, twigs, and logs, hereafter referred to as detritus). Because there are few physical openings into cave systems, the amount of detritus washed into caves is typically very low, so cave communities are assumed to be energy-limited. However, this energy-limitation hypothesis has never been tested, despite it being central to scientific understanding of cave ecology, evolution, and conservation. This study has been designed to be the first rigorous test of this hypothesis. The study design is elegantly simple: corn litter (leaves, stalks, and husks leftover from corn harvest) were added to a 100-m reach of a cave stream (Bluff River Cave, Jackson Co., AL) beginning in February 2010. The response of the stream community to this addition of energy will be followed for one year relative to that of a reference reach upstream (which will receive no litter). Additionally, over one year of pre-manipulation data (October 2008 to February 2010) has already been collected from both reaches. Samples will be collected monthly to track changes in species composition, abundance, and growth, as well as the incorporation of corn-derived material into animal tissue. This study will examine the response of the entire food web of the cave stream, from the most basal consumer (the bacteria and fungi that consume natural detritus and the added corn litter) to top predators (cave crayfish and salamanders). Thus, not only is this study the first to test the energy-limitation hypothesis, but it is also the first to characterize a cave stream's food web over an extended period of time. The results from this study will be valuable to various individuals and organizations. Conservation personnel and cave conservation groups will use the life history information (growth rates and time to maturity) obtained for the critically threatened Tennessee cave salamander (Gyrinophilus palleucus) and cave crayfishes (Cambarus tenebrosus and the imperiled Cambarus hamulatus). Cave systems are a window through which groundwater systems can be studied and monitored. Thus the general scientific community and society at large will benefit because groundwater systems are poorly understood but contain about 99% of all liquid freshwater on the planet, and provide important ecological services, including sustaining surface aquatic ecosystems, natural purification of water supplies, and maintenance of many highly endemic and endangered species. Results from this study will be shared both through scientific (journal articles, reports, and oral presentations) and public avenues (interactions with caving groups, landowners, state and federal agencies, and K-12 educators). As part of this project, a lesson plan for local high-school students has been developed, which teaches basic principles of cave and groundwater ecology, illustrates how ecology and evolution interact to structure cave communities, and introduces the concept of detritus-based food chains. To increase the number of students exposed to this material, the entire lesson plan (i.e., instructions, lectures, and activities) will be disseminated to local high-school teachers.

这项研究的总体目标是确定是否可用的能源限制洞穴溪流生态系统中的生物活动。 在洞穴生态系统中，位于食物网底部的资源，也就是潜在地控制整个生物活动的资源，是死的有机物（例如枯叶、树枝和原木，以下简称为碎屑）。 由于洞穴系统的物理开口很少，被冲入洞穴的碎屑量通常很低，因此洞穴群落被认为是能量有限的。 然而，这种能量限制假说从未被验证过，尽管它是科学理解洞穴生态，进化和保护的核心。 这项研究被设计为对这一假设的第一次严格检验。 研究设计非常简单：将玉米凋落物（玉米收获后剩下的叶子、茎和外壳）添加到100米长的洞穴溪流（海崖河洞穴，杰克逊公司，2010年2月开始。 流社区的反应，这种额外的能量将被跟踪一年相对于一个参考达到上游（这将不会收到垃圾）。 此外，已经从两个河段收集了一年多的操纵前数据（2008年10月至2010年2月）。 将每月收集样品，以跟踪物种组成、丰度和生长的变化，以及玉米衍生物质掺入动物组织的情况。这项研究将研究洞穴溪流的整个食物网的反应，从最基本的消费者（消耗天然碎屑和添加的玉米垃圾的细菌和真菌）到顶级捕食者（洞穴小龙虾和蝾螈）。 因此，这项研究不仅是第一个测试能量限制假说，但它也是第一个表征洞穴流的食物网在一段较长的时间。 这项研究的结果将对各种个人和组织有价值。 保护人员和洞穴保护小组将使用从极度濒危的田纳西洞穴蝾螈（Gyrinophilus pleuucus）和洞穴小龙虾（Cambarus tenebrosus和濒危的Cambarus hamulatus）获得的生活史信息（生长率和成熟时间）。 洞穴系统是研究和监测地下水系统的窗口。 因此，一般科学界和整个社会将受益，因为地下水系统知之甚少，但含有地球上约99%的液态淡水，并提供重要的生态服务，包括维持地表水生生态系统，供水的自然净化，以及维持许多高度地方性和濒危物种。 这项研究的结果将通过科学（期刊文章，报告和口头报告）和公共渠道（与洞穴群，土地所有者，州和联邦机构以及K-12教育工作者的互动）进行分享。作为该项目的一部分，已为当地高中学生制定了一个课程计划，讲授洞穴和地下水生态学的基本原理，说明生态学和进化如何相互作用以构建洞穴群落，并介绍碎屑食物链的概念。为了增加接触到这些材料的学生人数，整个课程计划（即，说明、讲座和活动）将传播给当地高中教师。