Aquatic macroinvertebrate biodiversity associated with artificial agricultural drainage ditches

M J Hill,P J Wood,J D Swaine,R P Chadd,N Morris

doi:10.1007/s10750-016-2757-z

Abstract

Agricultural drainage ditches are ubiquitous features in lowland agricultural landscapes, built primarily to facilitate land drainage, irrigate agricultural crops and alleviate flood risk. Most drainage ditches are considered artificial waterbodies and are not typically included in routine monitoring programmes, and as a result the faunal and floral communities they support are poorly quantified. This paper characterises the aquatic macroinvertebrate diversity (alpha, beta and gamma) of agricultural drainage ditches managed by an internal drainage board in Lincolnshire, UK. The drainage ditches support very diverse macroinvertebrate communities at both the site (alpha diversity) and landscape scale (gamma diversity) with the main arterial drainage ditches supporting greater numbers of taxa when compared to smaller side ditches. Examination of the between site community heterogeneity (beta diversity) indicated that differences among ditches were high spatially and temporally. The results illustrate that both main arterial and side ditches make a unique contribution to aquatic biodiversity of the agricultural landscape. Given the need to maintain drainage ditches to support agriculture and flood defence measures, we advocate the application of principles from ‘reconciliation ecology’ to inform the future management and conservation of drainage ditches.

Highlights

Land drainage improvements across Europe have historically been followed by the large-scale conversion of lowland wetlands to intensive arable production
This paper aims to highlight the aquatic macroinvertebrate biodiversity and conservation value associated with lowland agricultural drainage ditches over three seasons, and to discuss how principles of reconciliation ecology may provide a sustainable strategy for conserving biodiversity in ditches while supporting their wider societal and anthropogenic functions
Macroinvertebrate taxonomic richness was significantly greater within the main arterial ditches when compared with the side ditches (ANOVA F1,11 = 6.738; P = 0.027)

Summary

Introduction

Land drainage improvements across Europe have historically been followed by the large-scale conversion of lowland wetlands to intensive arable production. This has resulted in a wide range of documented changes and adverse effects upon biological communities across terrestrial, riparian and aquatic landscapes (Buisson et al, 2008; van Eerden et al, 2010). Contemporary European wetlands exist as isolated fragments of their former extent, with those that remain largely surrounded by agricultural land (Verdonschot et al, 2011). The only remaining aquatic habitat/refuges that exist in agricultural landscapes are ponds (e.g., Sayer et al, 2012) and drainage ditch networks. The potential importance of drainage ditch habitats in supporting aquatic biodiversity, the persistence of wetland floral or faunal communities, or species of conservation interest, has been poorly quantified internationally to date (Katano et al, 2003; Maltchik et al, 2011, Leslie et al, 2012; Vaikre et al, 2015)

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