@article {50230,
	title = {Shrub encroachment in North American grasslands: Shifts in growth form dominance rapidly alters control of ecosystem carbon inputs},
	journal = {Global Change Biology},
	volume = {14},
	year = {2008},
	month = {January 30, 2008},
	pages = {615-623},
	publisher = {Blackwell Publishing},
	abstract = {<p>Shrub encroachment into grass-dominated biomes is occurring globally due to a variety of anthropogenic activities, but the consequences for carbon (C) inputs, storage and cycling remain unclear. We studied eight North American graminoid-dominated ecosystems invaded by shrubs, from arctic tundra to Atlantic coastal dunes, to quantify patterns and controls of C inputs via aboveground net primary production (ANPP). Across a 4-fold range in mean annual precipitation (MAP), a key regulator of ecosystem C input at the continental scale, shrub invasion decreased ANPP in xeric sites, but dramatically increased ANPP (\&gt;1000 g/m2) at high MAP, where shrub patches maintained extraordinarily high leaf area. Concurrently, the relationship between MAP and ANPP shifted from being non-linear in grasslands to linear in shrublands. Thus, relatively abrupt (\&lt;50 yrs) shifts in growth form dominance, without changes in resource quantity, can fundamentally alter continental-scale pattern of C inputs and control by MAP in ways that exceed the direct effects of climate change alone.</p>
},
	keywords = {aboveground net primary production, carbon, climate change, encroachment, grass-dominated biomes, grasslands, growth form, LAI, MAP, North American, shrub, shrublands},
	doi = {10.1111/j.1365-2486.2007.01512.x },
	url = {/files/bibliography/08-005.pdf},
	author = {A. K. Knapp and J. M. Briggs and S.L. Collins and Steven R. Archer and M.S. Bret-Harte and Ewers, B. and Debra C. Peters and Young, D. and Shaver, G. and Cleary, M.B.}
}
