Functional trait composition of aquatic plants can serve to disentangle multiple interacting stressors in lowland streams

Baattrup-Pedersen, Annette; Gothe, Emma; Riis, Tenna; O'Hare, Matthew. T. 2016 Functional trait composition of aquatic plants can serve to disentangle multiple interacting stressors in lowland streams. Science of the Total Environment, 543 (A). 230-238. 10.1016/j.scitotenv.2015.11.027

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Official URL: http://dx.doi.org/10.1016/j.scitotenv.2015.11.027

Abstract/Summary

Historically, close attention has been paid to negative impacts associated with nutrient loads to streams and rivers, but today hydromorphological alterations are considered increasingly implicated when lowland streams do not achieve good ecological status. Here, we explore if trait-abundance patterns of aquatic plants change along gradients in hydromorphological degradation and eutrophication in lowland stream sites located in Denmark. Specifically, we hypothesised that: i) changes in trait-abundance patterns occur along gradients in hydromorphological degradation and ii) trait-abundance patterns can serve to disentangle effects of eutrophication and hydromorphological degradation in lowland streams reflecting that the mechanisms behind changes differ. We used monitoring data from a total of 147 stream reaches with combined data on aquatic plant species abundance, catchment land use, hydromorphological alterations (i.e. planform, cross section, weed cutting) and water chemistry parameters. Traits related to life form, dispersal, reproduction and survival together with ecological preference values for nutrients and light (Ellenberg N and L) were allocated to 41 species representing 79% of the total species pool. We found clear evidence that habitat degradation (hydromorphological alterations and eutrophication) mediated selective changes in the trait-abundance patterns of the plant community. Specific traits could distinguish hydromorphological degradation (free-floating, surface; anchored floating leaves; anchored heterophylly) from eutrophication (free-floating, submerged; leaf area). We provide a conceptual framework for interpretation of how eutrophication and hydromorphological degradation interact and how this is reflected in trait-abundance patterns in aquatic plant communities in lowland streams. Our findings support the merit of trait-based approaches in biomonitoring as they shed light on mechanisms controlling structural changes under environmental stress. The ability to disentangle several stressors is particularly important in lowland stream environments where several stressors act in concert since the impact of the most important stressor can be targeted first, which is essential to improve the ecological status.

Item Type:	Publication - Article
Digital Object Identifier (DOI):	10.1016/j.scitotenv.2015.11.027
UKCEH and CEH Sections/Science Areas:	Watt
ISSN:	0048-9697
Additional Keywords:	macrophyte, weed cutting, channelisation, eutrophication, habitat degradation, river
NORA Subject Terms:	Ecology and Environment
Date made live:	26 Feb 2016 12:27 +0 (UTC)
URI:	https://nora.nerc.ac.uk/id/eprint/513053

Item Type:

Publication - Article

Digital Object Identifier (DOI):

10.1016/j.scitotenv.2015.11.027

UKCEH and CEH Sections/Science Areas:

Watt

ISSN:

0048-9697

Additional Keywords:

macrophyte, weed cutting, channelisation, eutrophication, habitat degradation, river

NORA Subject Terms:

Ecology and Environment