Using waterplants as amphibian indicators

Posted on September 23, 2013

Predictable relationships in the make-up of different types of freshwater community (e.g., waterbirds and fish) mean that well known species can be used as indicators of other taxonomic groups.  However, surprisingly little work has been devoted to uncovering such correlations in freshwater systems.  Italian scientists argued that because water plants act as an intermediate link between amphibians and the broader pond environment, plants should be good indicators of both physicochemical conditions and the structure of amphibian communities.  The researchers sampled 26 semi-permanent fish-free ponds (all < 0.1 ha in area) in an environmental reserve in Tuscany and identified a total of 26 species of vascular water plants, one green alga, and seven amphibian species.   Using separate cluster analyses, the ponds were grouped on the basis of plant, amphibian and physico-chemical data, and the performance of each classification was then cross-tested on the other two data sets.  High levels of cluster correspondence were found, especially when the plant and amphibian clusters were used to predict physicochemical features, and when the  plant classification was used to predict amphibians.  The findings suggested that waterplants and amphibians were affected by the same environmental factors – particularly conductivity, pond size and pond depth.  Shallow ponds with high conductivity tended to support tall emergent plants such as bulrush (Typha spp.), which were preferred spawning sites for the common toad (Bufo bufo).  In contrast, deep, low conductivity ponds tended to have more plants with floating leaves (e.g.,  Potamogeton) or submerged leaves ( e.g., Chara), which were used as spawning surfaces by newts (Triturus spp.).  These findings show that plant assemblages can be used as surrogates for predicting environmental features and the presence of amphibian species.  From a conservation standpoint, they can help to identify ponds in need of specific management actions, such as the maintainance of sufficient depth for submerged-leaf plants and newts.

Reference:  Landi, M., Piazzini, S., Nucci, A., Saveri, C. & Angiolini, C.  2012.  Can macrophytes be a surrogate for amphibians and physico-chemical features in pond classifications?  Aquatic Botany 101, 1– 7.