Ionic identity of pore water influences pH preference in Collembola

Abstract

A test system described by Van Straalen and Verhoef (1997) was used in order to check whether the endogeic Collembolan Heteromurus nitidus was repelled by acid pH. In each of eight experimental runs sixteen naive animals were allowed to select sectors in a circular pH gradient made of pure quartz sand impregnated with McIlvaine's buffer solutions at constant osmolarity. Disodium or dipotassium hydrogen phosphate was mixed with citric acid in varying proportions, giving rise to acidity levels ranging from pH 2 to pH 9. The animals reacted quite differently according to whether Na or K was used as the metallic cation. With potassium, a strong variation was observed from one experimental box to another, H. nitidus aggregating at pH levels varying from 4 to 8, the most frequent aggregation being observed at pH 6. With sodium, aggregation occurred over a more restricted range, from pH 7 to pH 9, most frequent aggregation being at pH 8. It was concluded that the most acidic pH range (2-3) was avoided by the animals and that the chemical composition of buffer solutions strongly influenced results of pH-preference tests. If we consider that i) the absence of H. nitidus from acid soils (pH 5 to 3.5) can be explained by biological rather than by chemical effects, ii) this species can be cultured in acid as well as alkaline soils in the absence of predators, it ensures that potassium gives results that are more representative of the distribution of H. nitidus according to soil acidity than sodium.

Nitrogen addition changes the trophic cascade effects of spiders on a detrital food web

“…Previous work has indicated that even small changes in soil pH, comparable to what we observed in our study, impact Collembola species growth and development, reproduction, fecundity, and longevity (Salmon et al. ). Therefore, N addition enhanced the negative trophic cascade effects of spiders on decomposition by directly reducing Collembola abundance.…”

The ‘terril’ effect: Coal mine spoil tips select for collembolan functional traits in post-mining landscapes of northern France

“…An even more important reason was that the set of functional traits used in an ecological study is only a subset of the complete set of traits (including the so-called 'hard traits') needed to assess community responses to environmental change (Lavorel and Garnier, 2002;Garnier et al, 2004). In particular, concerning springtails, we are still in need of physiological traits explaining the response of species to factors such as soil acidity, one of the most complex (although highly influential) ecological determinants of species occurrence (Hågvar, 1990;Loranger et al, 2001;Salmon et al, 2002).…”

Structure of Poduromorpha (Collembola) communities in "restinga" environments in Brazil

“…Pozo (1986) and Cutz-Pool et al (2003) also identified the soil pH as one of the most important factors affecting springtail species distribution, favoring some species and causing the most sensitive ones to disappear. Collembola distribution in acid, neutral or alkaline soils can also be affected by human-induced changes to soil pH, altering their ecological needs (Salmon et al, 2002).…”