Cryptic species diversity: an overlooked factor in environmental management?

Abstract

Summary1. Molecular genetic methods continuously uncover cryptic lineages harboured by various species. However, from an applied perspective, it remains unclear whether and to which extent such a genetic diversity affects biological traits (e.g. ecological, behavioural and physiological characteristics) and environmental management. 2. We assessed potential deviations regarding the trait 'environmental stress tolerance' using individuals from five field populations of each of two cryptic lineages (called A and B) comprised under the nominal species Gammarus fossarum. We used ammonia as a chemical stressor while assessing the feeding rate on leaf discs as a measure of sublethal response. In this context, we established a restriction fragment length polymorphism assay to allow a rapid identification of the lineages. 3. We observed a biologically meaningful and statistically significant twofold higher overall tolerance of one cryptic lineage, lineage B, over the other. Confounding factors that may have the potential to influence the test results, such as life stage, sex, season of collection, parasitism, physiological status of organisms and upstream land-use patterns of the river catchments, were either controlled for or displayed only minor deviations between lineages. 4. Synthesis and applications. The trait differences observed in the present study seem to be mainly explained by the considerable genetic differentiation between cryptic lineages of one nominal species. Although traits other than tolerance have been minimally investigated in this context, this study indicates implications in the reliability and quality of environmental monitoring and management if cryptic lineage complexes are ignored.

Cryptic speciation and limited hybridization within Lumbricus earthworms (Clitellata: Lumbricidae)

“…The existence of cryptic lineages among such model morphospecies is problematic, as they may differ in both physiological and ecological traits (Feckler et al, 2013;Feckler et al, 2014). For L. rubellus it has been shown that two lineages vary in their methylation pattern in response to arsenic pollution (Kille et al, 2013).…”

Gammarus fossarum (Crustacea, Amphipoda) as a model organism to study the effects of silver nanoparticles

“…The different LC50s obtained between the two populations could be linked to the presence of different cryptic species (Feckler et al, 2014;Weiss et al, 2014), particular life-history traits specific to each population (e.g. size, reproduction, feeding habits, etc.)…”

The relative importance of diet-related and waterborne effects of copper for a leaf-shredding invertebrate

“…Seven days prior to their introduction into the bioassay, G. fossarum were kick-sampled in the Hainbach, Germany (49 14 0 N; 8 03 0 E), upstream of any agricultural activity, settlement, and wastewater inlet, where the local population is exclusively composed of cryptic lineage B (Feckler et al, 2014). Only visually non-parasitized adult males (6e8 mm body length) were used.…”