The effects of decapod crustacean macroconsumers on leaf detritus processing and colonization by invertebrates in stream habitats: A meta‐analysis

Abstract

We conducted a meta‐analysis of the available literature to assess the effect of decapod crustacean macroconsumers on the processing and invertebrate colonization of leaf detritus in streams. Supplementary methodological (experimental set‐up), geographical (i.e. latitude, climate) and biological (i.e. macroconsumers body size, detritus quality expressed as initial C:N ratio) data were collected, with the aim of assessing their influence on effect sizes variability. Overall, our results indicated some important effects of decapod crustacean macroconsumers on both detritus processing and colonization by invertebrates. Among the different factors examined, detritus quality and macroconsumer body size were important for predicting detritus processing and invertebrate colonization effects, respectively. This indicates that the pivotal role played by decapod crustacean macroconsumers on leaf decomposition, food webs, and wider stream ecosystem functioning, may be regulated by the interplay of both detritus chemistry and consumer's body size. The limitations and inadequacies of the analyzed literature are discussed.

Freshwater crabs (Decapoda: Pseudothelphusidae) increase rates of leaf breakdown in a neotropical headwater stream

“…Previous studies in tropical streams have documented varying effects of decapod macroconsumers on detrital processing. Some studies found that macroconsumers do not play a significant role in leaf breakdown (Rosemond et al, 1998), while other studies reported a significant effect of shredding by shrimps (Bobeldyk & Ramírez, 2007;Crowl et al, 2001;March, Benstead, Pringle, & Ruebel, 2001) and macroconsumers in general (Landeiro et al, 2008;Mancinelli et al, 2013;Moulton et al, 2010). Our results also suggest that the presence of crabs did not affect macroinvertebrate colonisation or persistence on leaves in the enclosures.…”

“…In contrast, decapod macroconsumers are prevalent in tropical streams and may play important functional roles in detrital processing (Dobson, Magana, Mathooko, & Ndegwa, 2002;Gessner et al, 2010;Moulton, Magalhães-Fraga, Brito, & Barbosa, 2010;Pringle, Hemphill, McDowell, Benarek, & March, 1999). For instance, studies investigating the effect of crayfish and shrimp on detrital processing have revealed that they are important in leaf litter breakdown (Crowl, McDowell, Covich, & Johnson, 2001;Mancinelli, Sangiorgio, & Scalzo, 2013;Schofield, Pringle, Meyer, & Sutherland, 2001). Freshwater crabs are also often found in leaf packs (Benstead, 1996;Bobeldyk & Ramírez, 2007;Rincón & Covich, 2014) and some researchers have proposed that freshwater crabs are strong interactors (sensu Paine, 1992) in benthic food webs (Mancinelli et al, 2013).…”

“…For instance, studies investigating the effect of crayfish and shrimp on detrital processing have revealed that they are important in leaf litter breakdown (Crowl, McDowell, Covich, & Johnson, 2001;Mancinelli, Sangiorgio, & Scalzo, 2013;Schofield, Pringle, Meyer, & Sutherland, 2001). Freshwater crabs are also often found in leaf packs (Benstead, 1996;Bobeldyk & Ramírez, 2007;Rincón & Covich, 2014) and some researchers have proposed that freshwater crabs are strong interactors (sensu Paine, 1992) in benthic food webs (Mancinelli et al, 2013). While many studies have documented the importance of mangrove crabs in litter processing and nutrient cycling (Lee, 1998;Nordhaus, Wolff, & Diele, 2006), few studies have quantified the roles of freshwater crabs in leaf breakdown.…”

A life-history account ofMacrobrachium spinipes(Schenkel, 1902) (Cherabin) in a large tropical Australian River

“…Migratory shrimps from the infraorder Caridea, from the families Atyidae, Xiphocaridae, and Palaemonidae, are important taxa in tropical river ecosystems (Bauer 2011a, Mancinelli et al 2013. These taxa often dominate the biomass of stream macroinvertebrate communities and, in some small streams, compose most of the faunal community biomass (e.g., Jardine 2014, Fièvet et al 2001.…”

Feeding habits of the freshwater crab Sodhiana iranica from Southern Iran

“…In tropical and subtropical zones, the paucity of grazers can be compensated by alternative decomposition pathways, which are favored by higher temperatures (Irons et al, 1994). However, decapod crustaceans bear a strong impact as macro consumers of vegetarian items (Cheshire et al, 2005;Mancinelli et al, 2013). The land crabs are unusual as the largest organisms to rely on plant matter as their main food source (Linton & Greenaway, 2007).…”