Publication Date:
2022-05-25
Description:
Author Posting. © The Authors, 2009. This is the author's version of the work. It is posted here by permission of John Wiley & Sons for personal use, not for redistribution. The definitive version was published in Global Change Biology 15 (2009): 1153-1172, doi:10.1111/j.1365-2486.2008.01801.x.
Description:
Global environmental change, related to climate change and the deposition of airborne N-containing
contaminants, has already resulted in shifts in plant community composition
among plant functional types in arctic and temperate alpine regions. In this paper, we review
how key ecosystem processes will be altered by these transformations, the complex biological
cascades and feedbacks that may result, and some of the potential broader consequences for
the earth system. Firstly, we consider how patterns of growth and allocation, and nutrient
uptake, will be altered by the shifts in plant dominance. The ways in which these changes
may disproportionately affect the consumer communities, and rates of decomposition, are
then discussed. We show that the occurrence of a broad spectrum of plant growth forms in
these regions (from cryptogams to deciduous and evergreen dwarf shrubs, graminoids and
forbs), together with hypothesized low functional redundancy, will mean that shifts in plant
dominance result in a complex series of biotic cascades, couplings and feedbacks which are
supplemental to the direct responses of ecosystem components to the primary global change
drivers. The nature of these complex interactions is highlighted using the example of the
climate-driven increase in shrub cover in low arctic tundra, and the contrasting
transformations in plant functional composition in mid-latitude alpine systems. Finally, the
potential effects of the transformations on ecosystem properties and processes which link with
the earth system are reviewed. We conclude that the effects of global change on these
ecosystems, and potential climate-change feedbacks, can not be predicted from simple
empirical relationships between processes and driving variables. Rather, the effects of
changes in species distributions and dominances on key ecosystem processes and properties
must also be considered, based upon best estimates of the trajectories of key transformations,
their magnitude and rates of change.
Description:
We thank the International Arctic Science Committee (IASC) for their support for this Mini-
Review as part of the IASC Circum-Arctic Terrestrial Biodiversity initiative (CAT-B) and as
part of International Polar Year 2007/2008.
Keywords:
Arctic
;
Alpine
;
Carbon
;
Ecosystem
;
Energy
;
Global change
;
Feedback
;
Nitrogen
;
Herbivory
;
Plant functional type
Repository Name:
Woods Hole Open Access Server
Type:
Preprint
Format:
image/jpeg
Format:
application/pdf
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