Uniting landscape and local condition: Describing the distribution and predicting the occurrence of wetland plant communities using a hydrogeologic setting approach.

摘要

My dissertation research explored the relationship between landscape variables and local wetland condition using field sampling, statistical analyses, and geographic information systems (GIS). Specifically I related the distribution and local condition of wetlands to acquired and/or derived landscape data using a hydrogeologic setting (HGS) approach.; Local condition of New York fens was related to landscape data by identifying significant landscape predictors of local wetland vegetation and hydrochemistry (i.e., HGS). Results suggested that four abiotic landscape variables comprised fen HGS (i.e., bedrock and surficial geology, topography, connection to surface water and wetland area) with measured variance among fens of the same category being attributed to biotic landscape properties and/or variation in local climate.; Using logistic regression, predictive models were developed that explained the distribution of known NY fens and historic fen vegetation using a HGS approach. Models correctly identified a majority of extant fens and a large percentage of historic fen vegetation while predicting their occurrence in only small areas of NY, validating the assumption that fens are rare because the HGS they occupy is rare.; I estimated the percentage of area and number of NY wetlands that were not protected by state mandate and could be classified as "isolated" under five different adjacency scenarios. I report that 26% of federally recognized wetland area in NY currently lacks state and federal protection and are therefore "at-risk" of adverse impact due to the recent relaxation of the Clean Water Act. Most (54%) of the "at-risk" wetland area could be protected with a 100 m definition of adjacency.; A conceptual framework for relating the local condition of wetlands to the chemical, physical and biologic integrity of surface waters within nested watersheds is presented. Using available landscape data, long-term water chemistry and field sampling I present a means of describing the contribution of wetlands to water quality, watershed function, and biological diversity across multiple spatial and temporal scales.