Addressing Wetland Conservation Issues by Combining Remote Assessment with Intensive Field Sampling.

摘要

Wetland ecosystems are delicate and unique systems providing services that are important to the ecological landscape. Wetlands in the United States have been experiencing a gradual degradation over the last two centuries and today a growing body of research is directed and understanding, protecting, and restoring these systems. The primary goal of this was to explore two methods of studying freshwater wetlands: a remote landscape level method and an intensive field sampling method to gain understanding of how each method can enhance the other. Field sampling is a traditional way of studying ecosystems and there is a considerable body of knowledge on various techniques, metrics, and indicators as they apply to wetlands. Remote sensing is a relatively new method of studying ecosystems that grew with the advancement of aerial photography and software capable of processing large data sets. In this dissertation Chapter I details a study comparing anuran, bird, fish, plant, and water quality metrics between 17 wetlands located in an environmentally degraded Great Lakes Area of Concern (AOC) and 10 natural reference wetlands. GIS landscape analysis was performed on all field sampled wetlands to discern some of the drivers of diversity differences between the two areas. The results indicated that whereas the AOC was not significantly different from reference sites in terms of ecological indicators, some landscape level components were significantly difference between the two areas. In Chapter II, a species distribution model (SDM) for the threatened Blanding's turtle (Emydoidea blandingii) was performed using a combination of 14 years of field capture records and surrounding landscape variables. Using the mapping and analysis software ArcGIS, two types of models were constructed and validated: a generalized linear model (GLM) using presence/absence records and Maxent model using presence/background records. The results indicated that GLM was not as successful as Maxent at predicting habitat suitability for E. blandingii and that the range of the species is limited by factors related to elevation. In Chapter III correlation analyses were performed on three levels of wetland bioassessment methods; remote sensing, rapid assessment, and exhaustive field sampling, to determine the level of overlap between these methods. Results indicated that some higher effort (Level Three) metric correlated strongly and significantly with lower effort (Level One) metrics suggesting that one Level could replace another if needed. When studying wetlands, it is evident that a combination of traditional field sampling methods and modern remote sensing methods provides the best assessment of the integrity of the wetland ecosystem.