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Does natural acidity mediate interactions between introduced brown trout, native fish, crayfish and other invertebrates in West Coast New Zealand streams?

Olsson, Karin LU ; Stenroth, Patrik LU ; Nyström, Per LU ; Holmqvist, Niklas LU ; McIntosh, A R and Winterbourn, M J (2006) In Biological Conservation 130(2). p.255-267
Abstract
The presence of introduced brown trout (Salmo trutta) on the distribution of native crayfish (Paranephrops planifrons), native galaxiid fishes (Galaxias spp.) and invertebrate fauna was investigated in 18 West Coast New Zealand streams (8 with trout and 10 without trout) differing in chemical characteristics. Gut contents of trout, crayfish and eels were also examined to evaluate whether competition or predation could be linked to the patterns found. Abundances of crayfish and galaxiids were significantly lower in streams with trout, but in streams without trout, substrate size was one of the most important factors determining crayfish abundance. In contrast to crayfish, other macroinvertebrates were more abundant in trout streams than... (More)
The presence of introduced brown trout (Salmo trutta) on the distribution of native crayfish (Paranephrops planifrons), native galaxiid fishes (Galaxias spp.) and invertebrate fauna was investigated in 18 West Coast New Zealand streams (8 with trout and 10 without trout) differing in chemical characteristics. Gut contents of trout, crayfish and eels were also examined to evaluate whether competition or predation could be linked to the patterns found. Abundances of crayfish and galaxiids were significantly lower in streams with trout, but in streams without trout, substrate size was one of the most important factors determining crayfish abundance. In contrast to crayfish, other macroinvertebrates were more abundant in trout streams than streams without trout and significantly more taxa were found in streams with trout. Macroinvertebrate abundance was related to environmental factors, such as pH, substrate, depth and total nitrogen. Gut content analysis showed an overlap in diet (mostly invertebrates) between trout and eels. Crayfish, however, had a more omnivorous diet where detritus was the most frequently occurring food material. Differences in chemical characteristics marked the streams with and without trout. Thus, trout were not present in streams with pH < 6.0. Crayfish and galaxiids were present in streams with pH ranging from 4.1 to 7.9, and those with pH < 6.0 may function as trout-free refuges where larger populations of these species may persist. However, other macroinvertebrate taxa may be more negatively affected by acidification than by trout. By protecting naturally acidic, brown water streams, New Zealand crayfish and galaxiid fish populations can be conserved within geographic areas where trout are present. (Less)
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author
organization
publishing date
type
Contribution to journal
publication status
published
subject
in
Biological Conservation
volume
130
issue
2
pages
255 - 267
publisher
Elsevier
external identifiers
  • wos:000238674000010
  • scopus:33645224655
ISSN
1873-2917
DOI
10.1016/j.biocon.2005.12.019
language
English
LU publication?
yes
id
690670e7-08ff-4a3a-8b7f-408a178206c1 (old id 159687)
date added to LUP
2007-06-28 15:54:23
date last changed
2019-02-20 04:38:49
@article{690670e7-08ff-4a3a-8b7f-408a178206c1,
  abstract     = {The presence of introduced brown trout (Salmo trutta) on the distribution of native crayfish (Paranephrops planifrons), native galaxiid fishes (Galaxias spp.) and invertebrate fauna was investigated in 18 West Coast New Zealand streams (8 with trout and 10 without trout) differing in chemical characteristics. Gut contents of trout, crayfish and eels were also examined to evaluate whether competition or predation could be linked to the patterns found. Abundances of crayfish and galaxiids were significantly lower in streams with trout, but in streams without trout, substrate size was one of the most important factors determining crayfish abundance. In contrast to crayfish, other macroinvertebrates were more abundant in trout streams than streams without trout and significantly more taxa were found in streams with trout. Macroinvertebrate abundance was related to environmental factors, such as pH, substrate, depth and total nitrogen. Gut content analysis showed an overlap in diet (mostly invertebrates) between trout and eels. Crayfish, however, had a more omnivorous diet where detritus was the most frequently occurring food material. Differences in chemical characteristics marked the streams with and without trout. Thus, trout were not present in streams with pH &lt; 6.0. Crayfish and galaxiids were present in streams with pH ranging from 4.1 to 7.9, and those with pH &lt; 6.0 may function as trout-free refuges where larger populations of these species may persist. However, other macroinvertebrate taxa may be more negatively affected by acidification than by trout. By protecting naturally acidic, brown water streams, New Zealand crayfish and galaxiid fish populations can be conserved within geographic areas where trout are present.},
  author       = {Olsson, Karin and Stenroth, Patrik and Nyström, Per and Holmqvist, Niklas and McIntosh, A R and Winterbourn, M J},
  issn         = {1873-2917},
  language     = {eng},
  number       = {2},
  pages        = {255--267},
  publisher    = {Elsevier},
  series       = {Biological Conservation},
  title        = {Does natural acidity mediate interactions between introduced brown trout, native fish, crayfish and other invertebrates in West Coast New Zealand streams?},
  url          = {http://dx.doi.org/10.1016/j.biocon.2005.12.019},
  volume       = {130},
  year         = {2006},
}