title: Species-soil associations, disturbance, and nutrient cycling in an Australian tropical rainforest.
abstract: Resource availability and disturbance are important factors that shape the composition, structure, and functioning of ecosystems. We investigated the effects of soil fertility and disturbance on plant-soil interactions and nutrient cycling in a diverse tropical rainforest. Our goal was to determine how common soil specialisation is among species and how plant-soil interactions affect ecosystem functioning in the presence of disturbance. Most species (59%) showed significant fidelity to either fertile (basalt) or infertile (schist) soils. Obligate schist specialists (six species) contributed 39 and 37% to total stand-level basal area and aboveground net primary productivity, respectively. High nutrient use efficiency of schist specialists reduced the rates of within-stand nutrient cycling through the production of nutrient-poor plant tissues and litter. Although forests on schist soils had higher basal area and similar rates of productivity to forests on basalt, uptake of Mg, K, P, and N were markedly less on schist than on basalt, particularly after a cyclone disturbance. Stands on schist soils were also less affected by the cyclone and, as a result, contributed less (ca. 50%) Mg, K, P, and N inputs to the forest floor (via litterfall) than stands on basalt soils. System "openness" (i.e. the risk of nutrient loss) from cyclone-affected basalt forests was minimised by high rates of uptake following disturbance and large effective cation exchange capacities of soils. Soil-plant-disturbance interactions are likely to engender different fitness-enhancing strategies on fertile and infertile soils, possibly leading to the development and/or maintenance of diversity in rainforests.
authors.affiliation: School of Biological Sciences, Monash University, Bld 18, Victoria 3800, Australia. sgleason@bio.mq.edu.au
authors.forename: Sean Michael
authors.initials: SM
authors.lastname: Gleason
authors.forename: Jennifer
authors.initials: J
authors.lastname: Read
authors.forename: Adrian
authors.initials: A
authors.lastname: Ares
authors.forename: Daniel J
authors.initials: DJ
authors.lastname: Metcalfe
mesh_terms: D002244:Carbon / Q000378:metabolism; D055867:Cyclonic Storms; D017753:Ecosystem; D005502:Food; D008670:Metals / Q000378:metabolism; D009584:Nitrogen / Q000378:metabolism; D010758:Phosphorus / Q000378:metabolism; D011157:Population Dynamics; D011793:Queensland; D011891:Rain; D012307:Risk Factors; D012621:Seasons; D017640:Silicates / Q000378:metabolism; D012987:Soil / Q000032:analysis*; D013045:Species Specificity; D013997:Time Factors; D014197:Trees / Q000145:classification / Q000254:growth & development / Q000378:metabolism*; D014329:Tropical Climate
chemical_list: D008670:Metals; D017640:Silicates; D012987:Soil; C060346:basalt; D010758:Phosphorus; D002244:Carbon; D009584:Nitrogen