Direct and indirect effects of an invasive omnivore crayfish on leaf litter decomposition

Carvalho, Francisco; Pascoal, Cláudia; Cássio, Fernanda; Sousa, Ronaldo

doi:10.1016/j.scitotenv.2015.09.125

Cited by 17 publications

(14 citation statements)

References 50 publications

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“…This organic matter is likely to be consumed by other shredders (such as amphipods, MacNeil et al 2011; Piscart et al 2011), whilst these are likely to be consumed also by decapods (Dunoyer et al 2014). Production of FPOM and DOC was higher in the invasive decapod treatments, likely a result of consumption and processing of leaf material (including nutrients, FPOM, DOC) through the decapod gut, as opposed to mechanical breakdown (Montemarano et al 2005; Carvalho et al 2016).…”

Section: Discussionmentioning

confidence: 99%

Transformation of detritus by a European native and two invasive alien freshwater decapods

et al. 2018

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Invasive alien species have the potential to alter biodiversity and ecosystem processes. In freshwaters, detritus decomposition is a major ecosystem service but it remains uncertain whether invasive alien decapods process detritus differently to natives. This study examined leaf litter processing, and cascading effects on biofilms, by the European native white clawed crayfish (Austropotamobius pallipes) compared to two invasive alien decapod species: the American signal crayfish (Pacifastacus leniusculus) and the Chinese mitten crab (Eriocheir sinensis). Invasive alien decapods were responsible for higher leaf litter decomposition than the native. In comparison with native crayfish, invasive alien crab and crayfish showed higher rates of litter consumption, increased production of smaller leaf fragments, fine particulate organic matter (FPOM) and dissolved organic carbon. Nutrients (ammonia and soluble reactive phosphorous) derived from excretion (measured separately in the absence of biofilms) varied among decapod species, being lower for P. leniusculus. However, nutrient concentrations did not vary among species in the detritivory experiments with biofilm, implying nutrients were utilised for biofilm production and respiration as no differences in biomass were evident among decapod treatments. These results show invasive alien decapods have the potential to increase the magnitude of detrital processing to FPOM in rivers, but indirect impacts on primary producers due to nutrient release are uncertain based on this experimental context.

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Section: Discussionmentioning

confidence: 99%

Transformation of detritus by a European native and two invasive alien freshwater decapods

et al. 2018

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“…They are omnivorous and their diet may include invertebrates, macrophytes, periphyton, detritus, fish, and other crayfish (Lirås et al., 1998; Momot, 1995; Nyström et al., 1996). They are commonly considered as ecosystem engineers, partly because of their role in the alteration of detrital processing rates (Carvalho et al., 2016; Creed & Reed, 2004), and by grazing plants (Creed, 1994; Matsuzaki et al., 2009; Nyström et al., 2001) and so are also considered keystone consumers (Gheradi et al., 2011; Reynolds, 2011).…”

Section: Introductionmentioning

confidence: 99%

Strong impacts of signal crayfish invasion on upland stream fish and invertebrate communities

2020

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Impacts of invasive signal crayfish Pacifastacus leniusculus on native species and ecosystems are widely recognised, but mostly through small‐scale studies and laboratory experiments that may not always reflect impacts in nature. Recorded effects of signal crayfish on fish populations are equivocal. In this study, using the before–after/control–impact and control–impact approaches, the effects of signal crayfish invasion on native fishes, particularly benthic fishes and young‐of‐year (YoY) salmonids, and macroinvertebrate communities, were determined on several spatial and temporal scales through three correlated study elements (S1–S3), in upland streams of the River Tees, England. In S1, we sampled fish and benthic macroinvertebrates of 18 streams identically in 2011 and 2018. These streams were categorised into two groups: (1) uninvaded (without signal crayfish in both sampling years; n = 7); and (2) invaded (with signal crayfish) streams, comprising pre‐invaded (invaded before 2011; n = 8) and newly invaded (invaded between 2011 and 2018, n = 3). Despite similar habitat conditions in both years (all variables p > 0.05) fish and macroinvertebrate communities changed over time in pre‐invaded streams and by comparison to uninvaded streams. A decline in the abundance of benthic fish and YoY salmonids was observed in pre‐invaded and newly invaded streams. Complete disappearance of bullhead Cottus perifretum following signal crayfish invasion was recorded in two pre‐invaded streams. In the second study, S2, we assessed within‐stream differences in fishes and macroinvertebrates in two Tees streams by comparing sections with (invaded) and without (uninvaded) signal crayfish. Compared to uninvaded sections, taxonomic richness and abundance of fish and macroinvertebrates were significantly lower in invaded sections, and the overall communities also differed significantly. In S3, long‐term data series (since 1990) of water quality and macroinvertebrates of six Tees streams comprising those invaded by signal crayfish (n = 3) and uninvaded (n = 3) were analysed. Water quality showed little change, or an improvement, over time but significant changes in the macroinvertebrate taxonomic richness and community structure occurred following signal crayfish invasion. Long‐term changes in macroinvertebrate communities in invaded streams tended to be due to declines in more sedentary taxa such as molluscs and cased trichopterans. Widespread and long‐term ecological disruption is occurring because of signal crayfish invasion in upland streams of the Tees catchment that may lead to a complete disappearance of some benthic fish species, as well as reduced densities of YoY salmonids and a shift towards less diverse macroinvertebrate communities, dominated by more mobile, crayfish‐resistant taxa.

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“…In Europe, numerous crayfish species have been introduced and they can be responsible for several ecological and economic impacts (Gherardi, 2006, Hobbs et al 1989. Crayfishes can have profound effects in water quality, nutrient dynamics, decomposition and community structure by acting as ecosystem engineers (Carvalho et al, 2016;Creed Jr. and Reed, 2004;Johnson et al, 2010;Matsuzaki et al, 2009;Sousa et al, 2013).…”

Section: Introductionmentioning

confidence: 99%

Invasive crayfishes as a threat to freshwater bivalves: Interspecific differences and conservation implications

Meira

Lopes‐Lima

Varandas

et al. 2019

Science of The Total Environment

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Freshwater bivalves have suffered major global declines, being the introduction of invasive alien species (IAS) an important, but not well studied, mechanism of threat. This study assessed the predator-prey relationship between two non-native crayfish species (Procambarus clarkii and Pacifastacus leniusculus) and three native (Anodonta anatina, Potomida littoralis and Unio delphinus) and one non-native (Corbicula fluminea) freshwater bivalve species through experiments in laboratory and validation under natural conditions (Sabor River basin, Portugal). All native bivalve species were preyed both in laboratory and in the field; however, both crayfish species were unable to prey C. fluminea. Predation was dependent on crayfish and bivalve species but was not affected neither by crayfish nor bivalve sizes. In the laboratory, the most preyed species by both crayfishes was A. anatina. On average, this species was preyed at least 12% more than other species, when crayfishes had a choice. Similar results were found in the field. We also found signs of competition between both crayfishes, being P. clarkii more dominant and aggressive as this species, on average, manipulated the bivalves 63.6% more times and 24:33 min longer than P. leniusculus, and initiated 55.8% more agnostic bouts. Our results support the idea that P. clarkii and P. leniusculus can affect native freshwater bivalves, but clear interspecific differences were detected. Both crayfishes may have direct and indirect impacts on bivalve populations by increasing mortality or by reducing their fitness. In addition, since both crayfishes do not prey C. fluminea, they offer this IAS another advantage over native bivalves. Given the widespread distribution of both P. clarkii and P. leniusculus and the threatened status of many freshwater bivalves, the dynamics and impacts of this relationship should be taken in account in the implementation of management measures devoted to the conservation of native freshwater bivalves.

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Direct and indirect effects of an invasive omnivore crayfish on leaf litter decomposition

Cited by 17 publications

References 50 publications

Transformation of detritus by a European native and two invasive alien freshwater decapods

Transformation of detritus by a European native and two invasive alien freshwater decapods

Strong impacts of signal crayfish invasion on upland stream fish and invertebrate communities

Invasive crayfishes as a threat to freshwater bivalves: Interspecific differences and conservation implications

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