Species traits predict assembly of mayfly and stonefly communities along pH gradients

Abstract

Much recent ecological research has centred on the interrelations between species diversity and ecological processes. In the present study, I show how species traits may aid in comprehending ecology by studying the link between an environmental variable and functional traits. I examined the composition of species traits with a theoretically underpinned relationship to ecological processes along a pH gradient. I focused on body size, reproductive output, life cycle length and feeding habit of mayflies and stoneflies. In mayfly assemblages, I found smaller body size, greater reproductive output, faster life cycles and a larger proportion of gathering collectors and scrapers with increasing pH. In stonefly assemblages, I found smaller body size, greater reproductive output and faster life cycles at sites with a history of long-term natural acidification, but no clear trends in feeding habits and in most traits where acidification is anthropogenic. The results suggest that mayflies and stoneflies exhibit different ecological functions following different ecological strategies. Mayflies follow an opportunistic strategy relative to stoneflies, likely facilitating high rates of ecological processes with respect to the autotrophic resource base at neutral sites. Relative to mayflies, stoneflies follow an equilibrium strategy contributing to ecological functioning in heterotrophic ecosystems and likely maintaining heterotrophic processes despite the erosion of species diversity in response to acidification. The rules governing an ecological community may be more readily revealed by studying the distribution of species traits instead of species diversity; by studying traits, we are likely to improve our understanding of the workings of ecological communities.

Environmental factors affecting mayfly assemblages in tufa-depositing habitats of the Dinaric Karst

“…Similar to the previously investigated freshwater systems of the Dinaric Karst (Vilenica et al, 2016b), water temperature and pH were amongst the most important variables that determined mayfly assemblages and their distribution (e.g. Gerhardt, 1990;Moog, 2002;Petrin, 2011;Bauernfeind and Soldán, 2012). In addition, habitat type (springs, upper lotic habitats, tufa barriers and lower lotic habitats) and ammonium concentrations also played an important role.…”

“…Majority of mayfly species inhabit freshwaters with a neutral to alkaline pH, whereas they are highly sensitive to low pH values (e.g. Gerhardt, 1990;Petrin, 2011). pH values of the karst streams and rivers usually range from 6.5 to 8.5, due to the geological effects of karst substrate (Štambuk-Giljanović, 2005).…”

Spatial distribution and seasonal changes of mayflies (Insecta, Ephemeroptera) in a Western Balkan peat bog

“…As water temperature was already recognized as one of the most important environmental factors influencing mayfly assemblages (e.g. Brittain 1979, Harper and Peckarsky 2006) and many authors showed that mayflies are very sensitive to low pH values (Fiance 1978, Gerhardt 1990, Petrin 2011), the results of this study are in accordance.…”

“…Moog 2002; Bauernfeind and Soldán 2012) and pH (e.g. Fiance 1978, Petrin 2011). Mayflies are highly sensitive to habitat alterations (e.g.…”

How do stream grazers partition their benthic habitat?

“…Species' distributions change over time and over the course of their development. Putting species into a meaningful ecological context requires an understanding of their life history, trait-based adaptations, and physiological limits, as well as the range of biotic and abiotic conditions to which they are exposed Vaughn, 2010;Petrin, 2011;Díaz et al, 2013). Because having such thorough knowledge of species is rarely possible, conceptual constructs like FFG provide useful shortcuts for understanding species' contributions to ecosystem functioning.…”