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能量的可用性是否限制了洞穴流生态系统中的生物活性。 在洞穴生态系统中，食物网的基础上的资源，因此可能控制整体生物学活动的资源是死去的有机物（例如，死叶，树枝，树枝和原木，以下称为碎屑）。 由于进入洞穴系统的物理开口很少，因此被洗净成洞穴的碎屑量通常非常低，因此假定洞穴群落是能量限制的。 然而，尽管这种能量限制假设从未进行过测试，尽管它是对洞穴生态，进化和保护的科学理解的核心。 这项研究被设计为对该假设的第一个严格检验。 研究设计非常简单：从2010年2月开始，将玉米窝（叶子，茎和果皮从玉米收获中剩下的）添加到100米的洞穴河流（Bluff River Cave，Jackson Co.，Al Al）中。相对于参考文献接收到上Upstream的那一年，该流社区对这种能量的响应将被遵循一年。 此外，已经从两者之间收集了超过一年的操作前数据（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，以及将玉米来源的材料掺入动物组织中。这项研究将研究洞穴流的整个食物网的反应，从最大的消费者（消耗天然碎屑的细菌和真菌）到顶级捕食者（洞穴小龙虾和sal）。 因此，这项研究不仅是第一个检验能量限制假设的研究，而且它也是第一个在很长一段时间内表征洞穴流的食物网的人。 这项研究的结果对各种个人和组织都很有价值。 保护人员和洞穴保护小组将使用对受到巨大威胁的田纳西州洞穴萨拉曼德（Gyrinbolus palleucus）和洞穴火鸡（Cambarus Tenebrosus和Imperized Cambarus hamulatus）获得的生命历史信息（增长率和成熟时间）。 洞穴系统是可以研究和监视地下水系统的窗户。 因此，一般的科学界和整个社会将受益，因为地下水系统的理解很少，但大约包含地球上所有液体淡水的99％，并提供重要的生态服务，包括维持地面水生生态系统，自然纯净供水以及维持许多高度流行和濒临灭绝的物种。 这项研究的结果将通过科学（期刊文章，报告和口头介绍）和公共途径（与洞穴群，土地所有者，州和联邦机构以及K-12教育家的互动）共享。作为该项目的一部分，已经制定了针对当地高中生的一项课程计划，该计划讲授了洞穴和地下水生态学的基本原理，它说明了生态和进化如何与结构洞穴社区相互作用，并介绍了基于碎屑的食物链的概念。为了增加暴露于此材料的学生人数，将把整个课程计划（即说明，讲座和活动）传播到当地的高中老师。