Transformation of detritus by a European native and two invasive alien freshwater decapods

Thomas M Doherty-Bone,Lee E Brown,Caroline Liddell,Alison M Dunn

doi:10.1007/s10530-018-1661-z

Thomas M Doherty-Bone, Lee E Brown + Show 2 more

Open Access

https://doi.org/10.1007/s10530-018-1661-z

Copy DOI

Journal: Biological Invasions	Publication Date: Jan 31, 2018
Citations: 12	License type: open-access

Affiliation: University of Leeds

Abstract

Invasive alien species have the potential to alter biodiversity and ecosystem processes. In freshwaters, detritus decomposition is a major ecosystem service but it remains uncertain whether invasive alien decapods process detritus differently to natives. This study examined leaf litter processing, and cascading effects on biofilms, by the European native white clawed crayfish (Austropotamobius pallipes) compared to two invasive alien decapod species: the American signal crayfish (Pacifastacus leniusculus) and the Chinese mitten crab (Eriocheir sinensis). Invasive alien decapods were responsible for higher leaf litter decomposition than the native. In comparison with native crayfish, invasive alien crab and crayfish showed higher rates of litter consumption, increased production of smaller leaf fragments, fine particulate organic matter (FPOM) and dissolved organic carbon. Nutrients (ammonia and soluble reactive phosphorous) derived from excretion (measured separately in the absence of biofilms) varied among decapod species, being lower for P. leniusculus. However, nutrient concentrations did not vary among species in the detritivory experiments with biofilm, implying nutrients were utilised for biofilm production and respiration as no differences in biomass were evident among decapod treatments. These results show invasive alien decapods have the potential to increase the magnitude of detrital processing to FPOM in rivers, but indirect impacts on primary producers due to nutrient release are uncertain based on this experimental context.

Highlights

Invasive alien species are organisms translocated by human action from their native range to a biogeographically novel locality, where they become established and spread (Blackburn et al 2011)
Nutrient concentrations did not vary among species in the detritivory experiments with biofilm, implying nutrients were utilised for biofilm production and respiration as no differences in biomass were evident among decapod treatments. These results show invasive alien decapods have the potential to increase the magnitude of detrital processing to fine particulate organic matter (FPOM) in rivers, but indirect impacts on primary producers due to nutrient release are uncertain based on this experimental context
Leaf litter decomposition rate differed significantly among species (Table 1), being greater for the invasive aliens E. sinensis and P. leniusculus compared to the native A. pallipes and the control (Fig. 1)

Summary

Introduction

Invasive alien species are organisms translocated by human action from their native range to a biogeographically novel locality, where they become established and spread (Blackburn et al 2011). Invasive alien species can alter community structure and modify ecosystem processes One major freshwater ecosystem process is the recycling of leaf litter and its transformation into other forms of energy and nutrient throughout the food web (Cummins et al 1973; Gessner et al 2010). Invasive species often differ from taxonomically analogous natives in physiological and behavioural traits (e.g. Dick et al 2014), and in their trophic position (Tran et al 2015). Species vary in their body elemental composition, which co-varies with their consumption of resources (Vanni 2002). Released nutrients are made available to primary trophic levels such as heterotrophic microbes and algae (Dyson et al 2007; Kominoski et al 2014)

Methods

Results

Conclusion