Editor’s Choice 100:3

Amy Austin discusses the Editor’s Choice for issue 3, by Alex Ireland & Robert Booth.  Enjoy!

Issue 3 will appear online next week. As usual, the issue will be filled with cracking papers! Happy Easter from Journal of Ecology!

Editor´s Choice March 2012

Human impact on the landscape through alteration of vegetation is occurring globally, with conversion of natural ecosystems for food production, industry and urban areas (Foley et al. 2005). However, one of the challenges for accurately assessing these impacts is the fact that the vast majority of our ecosystems have already been modified in some way. As such, it is difficult to know what the original impacts have been from land and forest clearing that occurred in these systems at least a century ago.  Perhaps even more complicated is trying to understand the impact on adjacent intact ecosystems, particularly non-point source changes in nutrient availability and biogeochemical cycling, which are critical components for understanding the integrated impact of land-use change on the landscape (Buffam et al. 2011). For example, eolian dust deposition due to human activity has increased markedly with the increase of agricultural expansion in North America (Neff et al. 2008), but at present, it is far from clear how ecosystems have been impacted from these alterations in nutrient pools and turnover.

The field site "Titus bog", studied in Ireland and Booth's paper. Photo credit: Robert K. Booth.

Pollen´s help in understanding the ecology of peatlands

An innovative look at how past land-use changes have altered the landscapes in temperate terrestrial ecosystems is the subject of the editor´s choice for this issue, Upland deforestation triggered by an ecosystem state-shift in a kettle peatland by Alex W. Ireland and Robert K. Booth. In this paper, the authors infer changes in vegetative composition, microbial communities and biogeochemical pools in peatland ecosystems using paleoecological tools of short-term sediment reconstruction. The study is a creative application of the tools of paleoecology to address an important question – how did initial deforestation of these landscapes impact adjacent wetland ecosystems at the onset of European settlement?  The authors used the pollen of Ambrosia (ragweed) as a marker in the sediments as a proxy for the timing of European arrival, as it is a plant species that is associated with disturbance. From this point forward in ´sediment´ time, the authors documented increases in nutrient availability in the years following initial land-use clearing, and most dramatically, an important shift in the vegetation in these peatland ecosystems from Spaghnum-dominated communities to those with a substantial representation by vascular plants. The authors infer that these changes also may have been the effectors of observed changes in the microbial community, and thus conclude that the ecosystem type itself was fundamentally altered, which would be difficult to identify today with the current state of these peatland ecosystems.

Authors Alex Ireland and Robert Booth. Photo credit:Travis Andrews.

Direct and indirect legacies

It is clear that land-use changes in the northeastern United States have had important direct impacts on temperate forest ecosystems and nitrogen cycling, (Goodale & Aber 2001) but this study is  one of the first clear evidences of the vulnerability of adjacent peatland ecosystems to nutrient enrichment from disturbance in other ecosystems. Particularly noteworthy is the fact that the net effect of these alterations was to reduce the carbon accumulation in these peatlands.  The dual direct and indirect impacts of the initial deforestation demonstrate the importance of strong legacy effects at both the community and ecosystem scale, and this study can serve as a cautionary tale for the possible unforeseen impacts of human activity in adjacent natural ecosystems.

Amy Austin
Associate Editor, Journal of Ecology

References

  • Buffam, I., Turner, M.G., Desai, A.R., Hanson, P.C., Rusak, J.A., Lottig, N.R., Stanley, E.H., & Carpenter, S.R. (2011) Integrating aquatic and terrestrial components to construct a complete carbon budget for a north temperate lake district. Global Change Biology, 17, 1193-1211.
  • Foley, J.A., DeFries, R., Asner, G.P., Barford, C., Bonan, G., Carpenter, S.R., Chapin, F.S., Coe, M.T., Daily, G.C., Gibbs, H.K., Helkowski, J.H., Holloway, T., Howard, E.A., Kucharik, C.J., Monfreda, C., Patz, J.A., Prentice, I.C., Ramankutty, N., & Snyder, P.K. (2005) Global consequences of land use. Science, 309, 570-574.
  • Goodale, C.L. & Aber, J.D. (2001) The long-term effects of land-use history on nitrogen cycling in northern hardwood forests. Ecological Applications, 11, 253-267.
  • Ireland, A. W. and Booth, R. K. (2012), Upland deforestation triggered an ecosystem state-shift in a kettle peatland. Journal of Ecology. doi: 10.1111/j.1365-2745.2012.01961.x
  • Neff, J.C., Ballantyne, A.P., Farmer, G.L., Mahowald, N.M., Conroy, J.L., Landry, C.C., Overpeck, J.T., Painter, T.H., Lawrence, C.R., & Reynolds, R.L. (2008) Increasing eolian dust deposition in the western United States linked to human activity. Nature Geoscience, 1, 189-195.
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