SGER: Unpredictable Events of Catastrophic Proportions in Temparate Forest Ecosystems: Developing a Baseline to Assess Cascading Effects and Coupled Interactions

最近发展起来的生态学理论认为，大扰动事件是大范围环境变化和演化的关键因素。断断续续的平衡和混沌理论假定系统在不同的稳定状态之间发生变化。对这些相对突然的变化的复杂动态的调查通常是在重大干扰发生后进行的，由于事件的突发性和不可预测性，可以用来描述事件之前的情况的数据相对较少。蝉的周期性大量出现是可以预测的，但它们发生的频率很低，足以构成灾难性程度的不可预测干扰事件的极好模型。这项用于探索性研究的小额赠款将从2002年夏天开始在印第安纳州中部建立一套基线测量，以期在2004年年中发生大规模蝉暴发。蝉在印第安纳州中部每17年爆发一次，那里的疫情规模是美国发现的最大的疫情之一。两次疫情之间的时间间隔如此之长，以至于蝉栖息的森林系统的大多数元素实际上对疫情的形式和特征没有工作记忆。在暴发前，蝉在地下大量消耗树根系统，而在暴发后，它们会迅速使树冠落叶。它们成为许多物种的猎物，随着野生动物狼吞虎咽地吞噬似乎无穷无尽的昆虫供应，它们成为许多物种的猎物，经常导致“捕食者饱和”，这种进食模式可能会极大地改变这些捕食者在疫情爆发当年和随后几年的存活率和繁殖率。产卵可能导致受影响树木的损害或死亡，失去树冠可能会改变林下小气候并影响蒸腾速率，进而影响地下水和地表溪流水文。为了开发基线信息，以评估2004年印第安纳州中部蝉暴发的影响，这个研究小组包括来自地理、生物、地质以及公共和环境事务部门的成员，将于2002年年中开始进行一系列测量。需要测量的变量包括营养动态、水文学、树冠覆盖率、树木生理学、苗木建立和社会经济因素。这一奖项将有助于建立基线测量，以便在未来几年进行后续研究。除了为广泛调查自然和人类系统之间的相互作用奠定基础外，该项目还将产生更广泛的积极影响，包括本科生和研究生的参与和培训，以及建立可用于广泛调查的数据库。

Recently developed ecological theories had identified major disturbance events as crucial factors in large-scale environmental change and evolution. Punctuated equilibrium and chaos theories posit shifts in systems between alternative stable states. Inquiries into the complex dynamics of these relatively abrupt shifts generally have taken place after major disturbances have occurred, with relatively little data available to characterize conditions prior to the events because of their suddenness and unpredictability. Periodic emergence of cicadas in massive numbers are predictable, but they occur infrequently enough to constitute an excellent model of unpredictable disturbance events of catastrophic proportions. This Small Grant for Exploratory Research will establish a set of baseline measurements in central Indiana starting in the summer of 2002 in anticipation of a major cicada outbreak in mid-2004. Cicada outbreaks occur every 17 years in central Indiana, where the size of the outbreak is among the largest found anywhere in the U.S. The time period between outbreaks is so long that most elements of the forest system that the cicadas inhabit effectively have no working memory of the form and character of the outbreak. Before the outbreak, cicadas underground are massive consumption of tree root systems, while after the outbreak, they can rapidly defoliate tree canopies. They become prey to a number of species, frequently inducing "predator saturation" as wildlife gorge on the seemingly endless supply of insects, an eating pattern that can dramatically alter the survival and reproduction rates of those predators during the year of the outbreak and in following years. The laying of eggs can lead to damage or death of affected trees, and loss of tree canopy can alter the microclimatology of the understory and affect transpiration rates, which in turn affects groundwater and surface stream hydrology. In order to develop baseline information against which to evaluate the impacts of the 2004 cicada outbreak in central Indiana, this research team, which includes members drawn from geography, biology, geology, and public and environmental affairs departments, will begin taking a series of measurements in mid-2002. Among variables to be measured are nutrient dynamics, hydrology, canopy cover, tree physiology, seedling establishment, and socioeconomic factors.This award will help establish baseline measurements from which follow-up studies can be conducted in the coming years. In addition to laying the groundwork for a broad range of inquiries into interactions between natural and human systems, the project will have positive broader impacts, including the involvement and training of undergraduate and graduate students and the establishment of databases that can be used for a broad range of inquiries.