| Popis: |
Evaluation of wetland ecological condition requires quantitative biological indices for measuring anthropogenic impairment. We implemented a modified floristic qual- ity assessment index (FQAI) protocol for 75 isolated, depressional herbaceous wetland systems, exploring refinements of FQAI standard methods. Species encountered during sampling (n = 397) were assigned coefficients of conservatism (CC) by ten expert botanists working independently. A quantitative summary metric of adjacent site buffer (up to 100 m) land use intensity, called the landscape development intensity (LDI) index, was cal- culated for each wetland system to quantify expected anthropogenic impairment. The as- sociation between LDI and wetland community mean CC scores was strong and condi- tionally independent of ecoregion. Weaker associations with LDI were observed for other community summary metrics, including richness-weighted FQAI. We inverted LDI to com- pute an intensity coefficient (IC), which quantifies observed buffer development intensity tolerated by each species. IC scores were significantly associated with CC scores on a species basis and strongly associated on a site mean basis. Growing interest in floristic quality assessment for regulatory purposes provides opportunities for formally linking expert opinion and ground observations of species-specific disturbance tolerance. |
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