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Impacts of an aggressive riparian invader on community structure and ecosystem functioning in stream food webs

Hladyz, Sally; Åbjörnsson, Kajsa LU ; Giller, Paul S. and Woodward, Guy (2011) In Journal of Applied Ecology 48(2). p.443-452
Abstract
P>1. Bioassessment in running waters has focused primarily on the impacts of organic pollution on community structure. Other stressors (e.g. invasive species) and impacts on ecosystem processes have been largely ignored in many riverine biomonitoring schemes, despite being required increasingly by environmental legislation. 2. Exotic riparian plants can exert potentially powerful stresses by altering both autochthonous and allochthonous trophic pathways. We examined the impact of Rhododendron ponticum on community structure and three key ecosystem processes (decomposition, primary production, and herbivory) in nine streams bordered by three characteristic vegetation types (deciduous woodland, pasture, or Rhododendron). 3. Community... (More)
P>1. Bioassessment in running waters has focused primarily on the impacts of organic pollution on community structure. Other stressors (e.g. invasive species) and impacts on ecosystem processes have been largely ignored in many riverine biomonitoring schemes, despite being required increasingly by environmental legislation. 2. Exotic riparian plants can exert potentially powerful stresses by altering both autochthonous and allochthonous trophic pathways. We examined the impact of Rhododendron ponticum on community structure and three key ecosystem processes (decomposition, primary production, and herbivory) in nine streams bordered by three characteristic vegetation types (deciduous woodland, pasture, or Rhododendron). 3. Community structure and ecosystem process rates differed among vegetation types, with autochthonous pathways being relatively more important in the pasture streams than in the woodland reference streams. Overall ecosystem functioning, however, was compromised in the invaded streams because both allochthonous and autochthonous inputs were impaired. Rhododendron's poor quality litter and densely shaded canopy suppressed decomposition rates and algal production, and the availability of resources to consumer assemblages. 4. Synthesis and applications. Combining measures of invertebrate abundance, rates of litter decomposition and algal production in future bioassessments of stream ecosystem functioning can help to make better informed management decisions and to develop more focused priorities for mediating the negative effects of riparian invasions. We provide a series of specific recommendations for dealing with invasive riparian plants in general, and Rhododendron in particular, in order to minimize their impacts on stream ecosystems. For instance, where the invader produces poor quality litter the canopy should be kept as open as possible over the stream channel to reduce impacts on algal production, thereby retaining alternative food chains that can be exploited by generalist consumers in the absence of viable detrital resources. (Less)
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author
organization
publishing date
type
Contribution to journal
publication status
published
subject
keywords
allochthonous subsidies, aquatic ecosystems, autochthonous production, decomposition, ecological stoichiometry, EU Water Framework Directive, invasive plants, Rhododendron ponticum, riparian zone, stable isotopes
in
Journal of Applied Ecology
volume
48
issue
2
pages
443 - 452
publisher
Wiley-Blackwell
external identifiers
  • wos:000288379000020
  • scopus:79952580553
ISSN
1365-2664
DOI
10.1111/j.1365-2664.2010.01924.x
language
English
LU publication?
yes
id
1eaa0e4a-cef6-464d-b3a7-6136f73d2976 (old id 1936186)
date added to LUP
2011-05-10 09:35:05
date last changed
2017-11-12 03:09:19
@article{1eaa0e4a-cef6-464d-b3a7-6136f73d2976,
  abstract     = {P>1. Bioassessment in running waters has focused primarily on the impacts of organic pollution on community structure. Other stressors (e.g. invasive species) and impacts on ecosystem processes have been largely ignored in many riverine biomonitoring schemes, despite being required increasingly by environmental legislation. 2. Exotic riparian plants can exert potentially powerful stresses by altering both autochthonous and allochthonous trophic pathways. We examined the impact of Rhododendron ponticum on community structure and three key ecosystem processes (decomposition, primary production, and herbivory) in nine streams bordered by three characteristic vegetation types (deciduous woodland, pasture, or Rhododendron). 3. Community structure and ecosystem process rates differed among vegetation types, with autochthonous pathways being relatively more important in the pasture streams than in the woodland reference streams. Overall ecosystem functioning, however, was compromised in the invaded streams because both allochthonous and autochthonous inputs were impaired. Rhododendron's poor quality litter and densely shaded canopy suppressed decomposition rates and algal production, and the availability of resources to consumer assemblages. 4. Synthesis and applications. Combining measures of invertebrate abundance, rates of litter decomposition and algal production in future bioassessments of stream ecosystem functioning can help to make better informed management decisions and to develop more focused priorities for mediating the negative effects of riparian invasions. We provide a series of specific recommendations for dealing with invasive riparian plants in general, and Rhododendron in particular, in order to minimize their impacts on stream ecosystems. For instance, where the invader produces poor quality litter the canopy should be kept as open as possible over the stream channel to reduce impacts on algal production, thereby retaining alternative food chains that can be exploited by generalist consumers in the absence of viable detrital resources.},
  author       = {Hladyz, Sally and Åbjörnsson, Kajsa and Giller, Paul S. and Woodward, Guy},
  issn         = {1365-2664},
  keyword      = {allochthonous subsidies,aquatic ecosystems,autochthonous production,decomposition,ecological stoichiometry,EU Water Framework Directive,invasive plants,Rhododendron ponticum,riparian zone,stable isotopes},
  language     = {eng},
  number       = {2},
  pages        = {443--452},
  publisher    = {Wiley-Blackwell},
  series       = {Journal of Applied Ecology},
  title        = {Impacts of an aggressive riparian invader on community structure and ecosystem functioning in stream food webs},
  url          = {http://dx.doi.org/10.1111/j.1365-2664.2010.01924.x},
  volume       = {48},
  year         = {2011},
}