Contrasting impacts of invasive engineers on freshwater ecosystems: an experiment and meta-analysis |
| |
Authors: | Shin-ichiro S Matsuzaki Nisikawa Usio Noriko Takamura Izumi Washitani |
| |
Institution: | (1) Department of Ecosystem Studies, Graduate School of Agricultural and Life Sciences, The University of Tokyo, 1-1-1 Yayoi, Bunkyo-ku, Tokyo 113-8657, Japan;(2) Research Center for Environmental Risk, National Institute for Environmental Studies, 16-2 Onogawa, Tsukuba Ibaraki, 305-8506, Japan |
| |
Abstract: | Invasion by common carp (Cyprinus carpio) and red swamp crayfish (Procambarus clarkii) in shallow lakes have been followed by stable-state changes from a macrophyte-dominated clear water state to a phytoplankton-dominated
turbid water state. Both invasive carp and crayfish are, therefore, possible drivers for catastrophic regime shifts. Despite
these two species having been introduced into ecosystems world-wide, their relative significance on regime shifts remains
largely unexplored. We compared the ecological impacts of carp and crayfish on submerged macrophytes, water quality, phytoplankton,
nutrient dynamics, zooplankton and benthic macroinvertebrates by combining an enclosure experiment and a meta-analysis. The
experiment was designed to examine how water quality and biological variables responded to increasing carp or crayfish biomass.
We found that even at a low biomass, carp had large and positive impacts on suspended solids, phytoplankton and nutrients
and negative impacts on benthic macroinvertebrates. In contrast, crayfish had a strong negative impact on submerged macrophytes.
The impacts of crayfish on macrophytes were significantly greater than those of carp. The meta-analysis showed that both carp
and crayfish have significant effects on submerged macrophytes, phytoplankton, nutrient dynamics and benthic macroinvertebrates,
while zooplankton are affected by carp but not crayfish. It also indicated that crayfish have significantly greater impacts
on macrophytes relative to carp. Overall, the meta-analysis largely supported the results of the experiment. Taken as a whole,
our results show that both carp and crayfish have profound effects on community composition and ecosystem processes through
combined consequences of bioturbation, excretion, consumption and non-consumptive destruction. However, key variables (e.g.
macrophytes) relating to stable-state changes responded differently to increasing carp or crayfish biomass, indicating that
they have differential ecosystem impacts. |
| |
Keywords: | Common carp Density manipulation experiment Ecosystem engineering Red swamp crayfish Regime shifts |
本文献已被 PubMed SpringerLink 等数据库收录! |
|