Human-Induced Trophic Cascades along the Fecal Detritus Pathway

摘要: Human presence and activity in tropical forest is thought to exert top-down regulation over the various ‘green-world’ pathways of plant-based foodwebs. However, these effects have never been explored for ‘brown-world’ fecal-detritus webs. The strong humans on game mammals are likely indirectly influence fecal detritivores (including Scarabaeine dung beetles), with subsequent indirect impacts detrivore-mediated plant-facilitating detrital processes. Across a 380-km gradient human western Brazilian Amazon, we conducted first landscape-level assessment human-induced cascade detritus pathway, by coupling data impact, mammal detritivore community structure, rate measurements key process (i.e. beetle-mediated secondary seed dispersal). We found evidence that impact influences both diversity biomass detritivores, but not detritivore-mediated Cascade strength varied across groups defined species' traits. smaller-bodied beetles were at higher risk local decline areas presence, body size was better predictor structure than resource manipulation strategy. also stronger upland, unflooded forests, seasonally flooded forests. Our results suggest food web mediated traits habitat type. Further research will be required determine conditions under which function.