Dickie, I.A., Yeates, G.W., St. John, M.G., Stevenson, B.A., Scott, J.T., Rillig,
M.C., Peltzer, D.A., Orwin, K.H., Kirschbaum, M.U.F., Hunt, J.E., Burrows, L.E.,
Barbour, M.M., Aislabie, J. (2011). Ecosystem service and biodiversity
trade-offs in two woody successions. Journal of Applied Ecology 48:
926–934.
Summary
1. Many grasslands worldwide are undergoing succession to woody vegetation,
causing complex effects on carbon (C) sequestration, nutrient cycling and
biodiversity. Land managers are frequently tasked with maximizing ecosystem
services and biodiversity. Nonetheless, there are few studies quantifying
trade-offs between ecosystem services and biodiversity during early woody
succession.
2. We assessed the consequences of woody succession for C stocks, above- and
below-ground taxa richness (plants, nematodes, mites, microbes, fungi), and
soil ecosystem function at one site with a native tree, Kunzea ericoides,
and one site with a non-native tree, Pinus nigra, both establishing
in conservation grasslands.
3. Woody succession at both sites was associated with large gains in
above-ground C stocks and, under P. nigra, losses from the mineral
soil-C pool.
4. Taxa richness responses were complex, nonlinear and incongruent. While
some taxa showed initial increases in richness with woody succession (e.g.
plants), other taxa had rapid declines (e.g. plant-feeding and
plant-associated nematodes, oribatid mites).
5. Below-ground ecosystem functioning shifted towards increased bacterial
energy channels with woody succession, despite no change in bacterial or
fungal biomass or fungal hyphal lengths. Most other soil measures were
consistent with literature expectations (increased C:N ratios, release of
recalcitrant phosphorus).
6. Synthesis and applications. Our gradient-based measurements of woody
succession effects on ecosystems did not follow expectations based on
comparing end-points of grasslands to homogeneous mature forest. The
discordance of biodiversity responses across taxonomic groups suggests that
managers cannot rely on the indicator-species concept to ensure conservation
of cryptic biodiversity. Carbon sequestration and biodiversity followed
non-congruent patterns, with significant losses of taxa richness from some
functional groups during woody succession. Management to maximize individual
ecosystem services such as carbon sequestration may therefore result in
significant negative effects on biodiversity of some, but not all, taxa.
Key-words: below-ground processes, biological invasion, carbon
sequestration, ecosystem properties, grassland, nutrient cycling, soil biota
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