Developing vegetation tools for assessing the ecological condition of wetlands in western Patagonia

Abstract

Aims: Floristic Quality Index (FQI) is a biological approach, widely used to evaluate wetland condition that incorporates plants' coefficients of conservatism (C values). However, Patagonia lacks wetland vegetation metrics with this information. We aimed to obtain a set of vegetation tools able to assess wetlands' ecological conditions. In particular, we (1) report the C-value scores for wetland plants, (2) evaluate the FQI effectiveness in detecting degradation, (3) identify the most reliable metrics for assessing the ecological status, and (4) examine tolerant and sensitive taxa along a total phosphorus (TP) stress gradient.Location: Western side of Patagonia, Argentina.Methods: We sampled vegetation in 76 wetlands that exhibited contrasting ecological conditions. Botanists assigned a C value to each species. We computed 30 metrics, including the FQI, mean C value, and measures of plant richness, diversity, and com- position. Generalized linear models and variance partitioning analysis were used to identify metrics with the greatest sensitivity to disturbance. Species-specific optimal and tolerance ranges for TP were also calculated.Results: Number of endemic species and sensitive taxa was the most effective metric, showing the highest sensitivity to TP. Although FQI exhibited a moderate sensitivity, its absolute specificity (TP as the only predictor) confirms its efficacy as a diag- nostic tool for eutrophication. Among individual species, helophytes were the most sensitive to disturbance, and exotics showed a strong positive association with TP.Conclusions: This work addresses a critical gap by providing the first adaptation of FQI for South America. Number of endemic and sensitive taxa emerged as the reliable metrics; notably, their assessment does not require sampling the entire wetland, as a qualified botanist can monitor the specific assemblages, saving time and effort. The identification of sensitive and tolerant taxa also provides a valuable and rapid assessment for eutrophication pressure. This work establishes a baseline for future research to refine C-value assignments and expand the FQI's application across broader disturbance gradients in Patagonia.