Will biodiversity loss in our forests influence key ecosystem services like the breakdown of organic matter and cycling of nutrients around the planet? An international team of scientists (including Wageningen UR scientists Frank Berendse, Jasper van Ruijven, Edwin Peeters and Veronique Vos) published in the prestigious journal Nature important new insights from the first-ever global litter decomposition experiment addressing the fundamental question of how changing biodiversity affects carbon and nitrogen cycling across strongly contrasting ecosystems.
The decomposition of dead organic matter is a key process in the cycling of carbon and nutrients on all continents. It is driven by a vast diversity of life structured in complex food webs, ranging from microorganisms like bacteria and fungi to larger organisms like millipedes, termites or amphipods. This diversity and the many interactions among these organisms make a mechanistic understanding of the role of biodiversity in decomposition challenging.
Biomes from the subarctic to the tropics
In a large-scale study conducted using an identical protocol at aquatic and terrestrial field sites across five biomes from the subarctic to the tropics, this team of 18 experts provides a comprehensive experimental assessment of the role of diversity in leaf litter decomposition allowing for some broad generalizations. “Our report shows that the loss of consumer and litter functional diversity slows carbon and nitrogen cycling across aquatic and terrestrial ecosystems,” Frank Berendse says. “In the current context of alarming rates of biodiversity loss across the planet, we clearly demonstrate that large-bodied organisms, that also face a greater extinction risk, are critical for the decomposition process.”
Importance of specific interactions
The study also highlights the importance of specific interactions between particular plant functional types arising in diverse litter mixtures that control these ecosystem functions. Frank Berendse: “Most strikingly, we report strong diversity effects arising when litter of N-fixing plants decomposes in mixtures with rapidly decomposing litter species suggesting N-transfer between litter types. This provides evidence, the first from a field study, for a general mechanism behind positive net diversity effects on decomposition. Our findings reinforce the perception that particular functional traits of organisms within biological communities are more powerful than species richness per se to explain key ecosystem functions and suggest that predicting patterns across strongly contrasting ecosystems may become within reach.”