The long-term effects of invasive signal crayfish (Pacifastacus leniusculus) on instream macroinvertebrate communities

Mathers, Kate L.; Chadd, Richard; Dunbar, Michael J.; Extence, Chris A.; Reeds, Jake; Rice, Stephen P.; Wood, Paul J.

doi:10.1016/j.scitotenv.2016.01.215

Cited by 49 publications

(67 citation statements)

References 89 publications

(114 reference statements)

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“…Stronger impacts might have been detected had the time period of the experiment been longer than 33 days, thereby allowing the decapods to consume more gastropods and physically alter the habitat of the mesocosm through additional bioturbation. The mesocosms in this study did not consistently sustain amphipod, leech or ephemeropteran populations that have been found to decline in the presence of decapods in other laboratory, mesocosm and field studies (Mathers et al., ; Rosewarne et al., ; Stenroth & Nyström, ). This suggests that effects on invertebrate communities might be stronger had this mesocosm array supported more species vulnerable to decapod predation.…”

Section: Discussioncontrasting

confidence: 58%

Multi‐faceted impacts of native and invasive alien decapod species on freshwater biodiversity and ecosystem functioning

et al. 2018

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Changes to species composition, such as biological invasions and extinctions, have the potential to alter ecosystems. Invaders often replace taxonomically similar species, resulting in potentially redundant impacts. For example, freshwater decapod crustaceans are pervasive invasive alien species but they often extirpate native decapods. This study addresses whether or not these compositional shifts lead to impacts on the structure of the macroinvertebrate community, key ecosystem functions such as decomposition rates and primary productivity, and freshwater properties such as turbidity. In a controlled outdoor mesocosm experiment that ran for 33 days, impacts on biodiversity, ecosystem functioning and properties were compared between a native, endangered crayfish (Austropotamobius pallipes) and two invasive alien decapods: the crayfish Pacifastacus leniusculus and crab Eriocheir sinensis. Equal densities of these decapod species were compared between mesocosms, with a replicated array of decapod free controls. Measurements included macroinvertebrate densities, decomposition of leaf litter, production of biofilms, plankton, macrophytes, gross primary productivity, turbidity, and dissolved nutrients. While taxonomic richness of non‐decapod macroinvertebrates was marginally higher in the invasive alien treatments, differences in Shannon diversity were negligible, and β‐diversity was higher for the invasive alien crab. Gastropod density was reduced in the benthos of invasive alien treatments. This was associated with increased primary productivity of periphyton, particularly in the presence of P. leniusculus. Increased turbidity was, however, inversely correlated with periphyton primary productivity in the E. sinensis treatment. Nitrate concentration was significantly lower in invasive compared to native crayfish mesocosms, but similar to decapod free controls. This reflects the potential for the invasive crayfish to act as a nitrogen sink, mediated through both enhanced periphyton and reduced nitrogen recycling. Other processes, such as decomposition rates, sediment respiration, community respiration, and gross primary productivity, did not differ between treatments. This study demonstrates impacts of both native and invasive alien decapod species on certain aspects of benthic biodiversity and ecosystem processes, but with many of these parameters unaffected. This assumes equal densities of each species in its environment. The enhanced gastropod predation and associated trophic cascade by invasive decapods are likely explained through higher consumption rates, metabolism and activity. These per‐capita impacts are likely to be exacerbated further in‐situ due to typically higher densities of invasive compared to native crayfish.

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Section: Discussioncontrasting

confidence: 58%

Multi‐faceted impacts of native and invasive alien decapod species on freshwater biodiversity and ecosystem functioning

et al. 2018

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“…Accordingly, in mesocosm experiments amphipods were the only prey group that E. sinensis affected more strongly than P. leniusculus (Rosewarne et al 2016). Amphipods and other motile taxa may be amongst the least affected by crayfish in the field (Crawford et al 2006;Mathers et al 2016), so we would expect their FRs to be low. Eriocheir sinensis also had a relatively high feeding rate on chironomid larvae: at least 1.9 times greater than the crayfish.…”

Section: Pacifastacus Leniusculusmentioning

confidence: 96%

“…Eriocheir sinensis is native to the north-western Pacific but has been transported around the world, with key established populations on the west coast of the USA and in north-west Europe (Dittel and Epifanio 2009). Invasion by P. leniusculus can change community structure through a combination of competition, disease transmission and resource consumption (Crawford et al 2006;Dunn et al 2008;Twardochleb et al 2013;Mathers et al 2016). Evidence from mesocosms and field manipulations suggests E. sinensis may cause similar declines in macroinvertebrate populations through predation (Yu and Jiang 2005;Rudnick and Resh 2005;Rosewarne et al 2016).…”

Section: Introductionmentioning

confidence: 99%

Predatory impacts of alien decapod Crustacea are predicted by functional responses and explained by differences in metabolic rate

Taylor

Dunn

2018

Biol Invasions

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Alien predators can have large impacts on prey. It is important that we understand, and ideally predict, these impacts. Here, we compare predatory impacts of size-matched decapod crustaceans-invasive alien Eriocheir sinensis and Pacifastacus leniusculus, and native European Austropotamobius pallipes-and use this case study to inform methods for impact prediction. We quantify functional responses (FRs) on three macroinvertebrate prey species, examine switching behaviour, and measure metabolic rates as a possible mechanistic explanation for differences in predation. FRs show a consistent pattern: attack coefficients and maximum feeding rates are ordered E. sinensis≥P. leniusculus≥A. pallipes for all prey species. Attack coefficients of E. sinensis are up to 6.7 times greater than those of size-matched crayfish and maximum feeding rates up to 3.0 times greater. FR parameters also differ between the invasive and native crayfish, but only up to 2.6 times. We find no evidence of switching behaviour in crayfish but suggestions of negative switching in E. sinensis. Differences in FR parameters are mirrored by differences in routine, but not standard, metabolic rate. Overall, our data predict strong predatory impacts of E. sinensis, even relative to alien P. leniusculus. Strong impacts of P. leniusculus relative to A. pallipes may be driven more by body size or abundance than per capita effect. FRs vary between prey types in line with existing knowledge of impacts, supporting the use of FRs in quantitative, prey-specific impact predictions. MRs could offer a general mechanistic explanation for differences in predatory behaviour and impacts.

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“…, Mathers et al. ). The most widely recorded taxa affected by invasive crayfish colonization are Mollusca, with reductions in species richness, abundances, and biomass (e.g., Dorn , Ruokonen et al.…”

Section: Introductionmentioning

confidence: 99%

Predator, prey, and substrate interactions: the role of faunal activity and substrate characteristics

2019

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Many taxa possess a range of strategies to reduce the risk of predation, including actively seeking suitable refuge habitats; however, the global spread of invasive species may disrupt these behavioral responses. In lotic ecosystems, interstitial spaces in the substrate are important refugia for small organisms. Some predators are ecosystem engineers that exhibit zoogeomorphic agency-the ability to modify the geomorphology of their environment. It is therefore possible that direct ecological effects of predators on prey may be realized through modifications to the prey's habitat, including the availability of refugia, by predators that are zoogeomorphic agents or via external stressors such as fine sediment loading. This study examined three research questions in a mesocosm study across a gradient of sediment-stress treatments: (1) What affects do predators (Pacifastacus leniusculus, invasive crayfish) and prey (Gammarus pulex, amphipods) have on the ingress of fine sediment into gravel substrates and therefore on available interstitial refugia? (2) Do prey taxa seek refuge from (invasive) predators in the form of vertical movement into subsurface sediments? and (3) How does fine sediment ingress influence predator-prey interactions and prey survival through predator avoidance behavior. Here, we provide direct evidence demonstrating that fine sediment ingress into gravel river beds can be facilitated by zoogeomorphic activity with P. leniusculus increasing the infiltration of fine sand particles (but not coarse sand) during foraging activities. Predator-prey interactions were found to be a primary factor mediating zoogeomorphic activity, with the isolation of crayfish from prey (G. pulex) leading to increased fine sand ingress. When present with signal crayfish, G. pulex displayed vertical avoidance behavior, entering subsurface substrates to evade predation by P. leniusculus. Coarse sand treatments resulted in higher predation rates of G. pulex, most likely due to clogging of interstitial pore spaces between gravels limiting the effectiveness of the prey's vertical avoidance behavior strategy. A new conceptual model that captures the interactions between predator, prey, zoogeomorphic processes and habitat availability is presented. This model highlights how predator-prey interactions can be strongly mediated by dynamic bi-directional interactions between organisms and the physical environment they inhabit as ecological and geomorphological processes are intrinsically linked.

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The long-term effects of invasive signal crayfish (Pacifastacus leniusculus) on instream macroinvertebrate communities

Cited by 49 publications

References 89 publications

Multi‐faceted impacts of native and invasive alien decapod species on freshwater biodiversity and ecosystem functioning

Multi‐faceted impacts of native and invasive alien decapod species on freshwater biodiversity and ecosystem functioning

Predatory impacts of alien decapod Crustacea are predicted by functional responses and explained by differences in metabolic rate

Predator, prey, and substrate interactions: the role of faunal activity and substrate characteristics

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