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Size-dependent effects of an invasive herbivorous snail (Pomacea canaliculata) on macrophytes and periphyton in Asian wetlands

Carlsson, Nils LU and Brönmark, Christer LU (2006) In Freshwater Biology 51(4). p.695-704
Abstract
1. The invasive golden apple snail (Pomacea canaliculata), native to South America, is a serious pest on rice seedlings in south-east Asia and has also been shown to consume large amounts of macrophytes in natural wetlands, with large effects on ecosystem functioning. Earlier studies suggest that the snail undergoes an ontogenetic diet shift, feeding on algae and detritus as juveniles and shifting to aquatic macrophytes as adults.

2. Here, we study the effects of snail populations with a size-structure typical of either populations at an invasive front or the size-structure of established populations. In an enclosure experiment performed in a wetland in Laos, we compared treatments with small snails only (3 mm; invasive... (More)
1. The invasive golden apple snail (Pomacea canaliculata), native to South America, is a serious pest on rice seedlings in south-east Asia and has also been shown to consume large amounts of macrophytes in natural wetlands, with large effects on ecosystem functioning. Earlier studies suggest that the snail undergoes an ontogenetic diet shift, feeding on algae and detritus as juveniles and shifting to aquatic macrophytes as adults.

2. Here, we study the effects of snail populations with a size-structure typical of either populations at an invasive front or the size-structure of established populations. In an enclosure experiment performed in a wetland in Laos, we compared treatments with small snails only (3 mm; invasive treatment) to treatments with small, medium sized (10 mm) and adult (> 25 mm) snails (established treatment). The effects of snail grazing on three aquatic macrophyte species and periphytic algae were quantified.



3. We found that snails of all sizes had a strong negative effect on the biomass of all macrophyte species and periphytic algae. There was no evidence of an ontogenetic diet change, i.e. snails in both the invasive and established treatments affected macrophyte biomass. Foraging was size-dependent in that small snails had higher relative foraging capacity (g plant consumed per g of snail) compared with medium and adult snails. Small snails, therefore, depressed growth of medium snails at increasing densities through exploitative competition for preferred resources, while adult snails did not grow at all in the presence of small snails.



4. Density dependence is common in freshwater invertebrates, including gastropod populations, but differences in size dependent foraging- and competitive-ability have rarely been demonstrated in this group of organisms. Knowledge about intra-specific differences in ecological performance may, however, both deepen our understanding of the processes that underlie population dynamics in invertebrates such as gastropods, and help develop control strategies for invasive golden apple snails. (Less)
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author
organization
publishing date
type
Contribution to journal
publication status
published
subject
in
Freshwater Biology
volume
51
issue
4
pages
695 - 704
publisher
Wiley-Blackwell
external identifiers
  • wos:000236022900008
  • scopus:33645103970
ISSN
0046-5070
DOI
10.1111/j.1365-2427.2006.01523.x
language
English
LU publication?
yes
id
6131d21d-39d1-437b-a9c3-83d5184b0f11 (old id 159376)
date added to LUP
2007-06-28 12:42:42
date last changed
2019-10-15 05:10:02
@article{6131d21d-39d1-437b-a9c3-83d5184b0f11,
  abstract     = {1. The invasive golden apple snail (Pomacea canaliculata), native to South America, is a serious pest on rice seedlings in south-east Asia and has also been shown to consume large amounts of macrophytes in natural wetlands, with large effects on ecosystem functioning. Earlier studies suggest that the snail undergoes an ontogenetic diet shift, feeding on algae and detritus as juveniles and shifting to aquatic macrophytes as adults. <br/><br>
2. Here, we study the effects of snail populations with a size-structure typical of either populations at an invasive front or the size-structure of established populations. In an enclosure experiment performed in a wetland in Laos, we compared treatments with small snails only (3 mm; invasive treatment) to treatments with small, medium sized (10 mm) and adult (&gt; 25 mm) snails (established treatment). The effects of snail grazing on three aquatic macrophyte species and periphytic algae were quantified.<br/><br>
<br/><br>
3. We found that snails of all sizes had a strong negative effect on the biomass of all macrophyte species and periphytic algae. There was no evidence of an ontogenetic diet change, i.e. snails in both the invasive and established treatments affected macrophyte biomass. Foraging was size-dependent in that small snails had higher relative foraging capacity (g plant consumed per g of snail) compared with medium and adult snails. Small snails, therefore, depressed growth of medium snails at increasing densities through exploitative competition for preferred resources, while adult snails did not grow at all in the presence of small snails.<br/><br>
<br/><br>
4. Density dependence is common in freshwater invertebrates, including gastropod populations, but differences in size dependent foraging- and competitive-ability have rarely been demonstrated in this group of organisms. Knowledge about intra-specific differences in ecological performance may, however, both deepen our understanding of the processes that underlie population dynamics in invertebrates such as gastropods, and help develop control strategies for invasive golden apple snails.},
  author       = {Carlsson, Nils and Brönmark, Christer},
  issn         = {0046-5070},
  language     = {eng},
  number       = {4},
  pages        = {695--704},
  publisher    = {Wiley-Blackwell},
  series       = {Freshwater Biology},
  title        = {Size-dependent effects of an invasive herbivorous snail (Pomacea canaliculata) on macrophytes and periphyton in Asian wetlands},
  url          = {http://dx.doi.org/10.1111/j.1365-2427.2006.01523.x},
  volume       = {51},
  year         = {2006},
}