We are especially excited about this issue of Journal of Ecology because it includes a Special Feature, guest-edited by James Bullock and Ran Nathan, on the fast-moving topic of plant dispersal across multiple scales. As noted in their Editorial, the study of dispersal has undergone a revival in recent years, driven largely by a growing recognition that easily-observed dispersal at local scales cannot be simply extrapolated to yield understanding and prediction of processes at larger scales. This Special Feature draws together 12 papers on a wide range of questions related to the use of modelling in dispersal research, the complexity of plant dispersal, and the integration of dispersal with demography to gain a better understanding of spatial population dynamics. Collectively, these papers provide an essential overview of recent progress and current understanding in this rapidly growing area. We are pleased to announce that all papers in this special issue are free access for a limited period of time; we very much hope that you enjoy reading them.
In addition to the Special Feature, this issue includes our normal range of high quality papers; as always, it is a difficult task selecting one as Editor’s Choice. But, the paper that I have selected is by Lucía Vivanco and Amy Austin, who explored the influence of individual tree species and tree species mixtures on litter decomposition processes in mixed forest in temperate South America. Many studies have explored effects of litter diversity and composition on rates of decomposition. However, as noted by Vivanco and Austin, studies on the effects of litter diversity on decomposition are often complicated by differences in the spatial and temporal scale that plant and soil processes operate, and also the potential for long-lived plants, especially trees, to modify their surrounding soil environment in a way that might effect rates decomposition. Here, Vivanco and Austin overcame this problem using a novel approach that allowed them isolate the effects of single tree species and their mixtures on soil properties and rates of decomposition in an old-growth forest in Patagonia. They did this by locating “tree-triangles” in the forest, i.e., locations where the intersection of canopies of three different tree species controlled the soil environment of the forest floor, and mono-specific stands where the “tree-triangle” was composed of three individuals of the same species. The use of this approach, combined with the placement within “tree-triangles” of litterbags containing litters of single species and mixtures of all three canopy species, allowed the simultaneous study of direct effects of litter composition and indirect effects of living trees on the decomposition micro-environment in this temperate forest system.
Using this approach, Vivanco and Austin found that tree species affected rates of litter decomposition through both direct and indirect effects: direct effects were driven by differences in litter quality amongst the three tree species, whereas indirect effects were caused by the unique soil conditions that the tree species created in their immediate soil environment. The most surprising discovery, however, was that individual tree species modified their soil environment in such a way that enhanced the decomposition of their own litter; in other words, species-specific plant-soil interactions created a home-field advantage for the breakdown of the species’ own litter. The mechanisms involved in this response were not tested, but it is suggested that trees might encourage the development of soil decomposer communities that rapidly decompose their own litter, thereby creating a home-field advantage. While further studies are needed to test the generality of this response and the mechanisms involved, these findings highlight that long-term plant-soil feedbacks are important in affecting litter decomposition and potentially forest dynamics at the ecosystem scale, and that changes in temperate forest biodiversity - for example caused by climate change - can directly impact on litter decomposition through altered litter input quality and, additionally, through modifying specific plant-soil interactions that affect belowground processes. Moreover, these findings contribute to the growing awareness that feedbacks between aboveground and belowground communities can act as important structuring forces in terrestrial ecosystems.
We hope you will enjoy reading the latest research from Journal of Ecology. If you have any comments about our published output we would be pleased to hear them. Please write to the Managing Editor.
Editor, Journal of Ecology
Tree species identity alters forest litter decomposition through long-term plant and soil interactions in Patagonia, Argentina
Lucía Vivanco and Amy T. Austin
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