02036nas a2200301 4500008004100000022001400041245011600055210006900171260001600240300001100256490000800267520115100275653001201426653002901438653001601467653001901483653002301502653002401525653000901549653002001558653001901578100001601597700001801613700001601631700001501647700002001662856005201682 1998 eng d a0048-969700aImpact of the New Zealand flatworm (Artioposthia triangulata) on soil structure and hydrology in the UK.0 aImpact of the New Zealand flatworm iArtioposthia triangulatai on c1998 May 04 a259-650 v2153 a

Through north west Europe, concern has been growing in recent years about the predatory nature of Artioposthia triangulata on indigenous earthworm species. In this study, the consequence of earthworm depletion by A. triangulata on soil structure and related hydrological processes is examined. Field measurements compare differences in saturated hydraulic conductivity between sites overrun by A. triangulata and neighbouring unaffected sites. Laboratory experiments were conducted on soil cores containing worms only, worms and A. triangulata, and a control with no worms or A. Triangulata. Differences in the water release characteristic and bulk density between treatments was studied. It is concluded that in the short term, infestation by flatworms and consequent depletion of earthworms will increase infiltration. However, as macropores degenerate or are removed over time, an increased risk of surface run off may result in increased pollution and flood hazards, whilst reduced drainage and subsequent waterlogging may reduce agricultural productivity in certain soils. More research into understanding the processes is required.

10aAnimals10aEnvironmental Monitoring10aOligochaeta10aPlatyhelminths10aPredatory Behavior10aRegression Analysis10aSoil10aSoil Pollutants10aUnited Kingdom1 aHaria, A, H1 aMcGrath, S, P1 aMoore, J, P1 aBell, J, P1 aBlackshaw, R, P uhttps://continenticola.myspecies.info/node/173303050nas a2200313 4500008004100000022001400041245010100055210006900156260001300225300001100238490000700249520216500256653001202421653001202433653001702445653001502462653002302477653002302500653001502523653001702538653002302555653001202578653001102590100001702601700002102618700002502639700002002664856005202684 2014 eng d a1365-265600aPredator effects on a detritus-based food web are primarily mediated by non-trophic interactions0 aPredator effects on a detritusbased food web are primarily media c2014 Jul a953-620 v833 a

Predator effects on ecosystems can extend far beyond their prey and are often not solely lethally transmitted. Change in prey traits in response to predation risk can have important repercussions on community assembly and key ecosystem processes (i.e. trait-mediated indirect effects). In addition, some predators themselves alter habitat structure or nutrient cycling through ecological engineering effects. Tracking these non-trophic pathways is thus an important, yet challenging task to gain a better grasp of the functional role of predators. Multiple lines of evidence suggest that, in detritus-based food webs, non-trophic interactions may prevail over purely trophic interactions in determining predator effects on plant litter decomposition. This hypothesis was tested in a headwater stream by modulating the density of a flatworm predator (Polycelis felina) in enclosures containing oak (Quercus robur) leaf litter exposed to natural colonization by small invertebrates and microbial decomposers. Causal path modelling was used to infer how predator effects propagated through the food web. Flatworms accelerated litter decomposition through positive effects on microbial decomposers. The biomass of prey and non-prey invertebrates was not negatively affected by flatworms, suggesting that net predator effect on litter decomposition was primarily determined by non-trophic interactions. Flatworms enhanced the deposition and retention of fine sediments on leaf surface, thereby improving leaf colonization by invertebrates - most of which having strong affinities with interstitial habitats. This predator-induced improvement of habitat availability was attributed to the sticky nature of the mucus that flatworms secrete in copious amount while foraging. Results of path analyses further indicated that this bottom-up ecological engineering effect was as powerful as the top-down effect on invertebrate prey. Our findings suggest that predators have the potential to affect substantially carbon flow and nutrient cycling in detritus-based ecosystems and that this impact cannot be fully appreciated without considering non-trophic effects.

10aAnimals10aBiomass10aCarbon Cycle10aFood Chain10aGeologic Sediments10aModels, Biological10aplanarians10aPlant Leaves10aPredatory Behavior10aQuercus10aRivers1 aMajdi, Nabil1 aBoiché, Anatole1 aTraunspurger, Walter1 aLecerf, Antoine uhttps://continenticola.myspecies.info/node/1723