Controls of Aboveground Net Primary Production in Mesic Savanna Grasslands: An Inter-Hemispheric Comparison

被引:49
作者
Buis, Greg M. [1 ,11 ]
Blair, John M. [2 ]
Burkepile, Deron E. [3 ,4 ]
Burns, Catherine E. [3 ,5 ]
Chamberlain, Annikki J. [6 ]
Chapman, Phillip L. [7 ]
Collins, Scott L. [8 ]
Fynn, Richard W. S. [9 ]
Govender, Navashni [10 ]
Kirkman, Kevin P. [9 ]
Smith, Melinda D. [3 ]
Knapp, Alan K. [11 ]
机构
[1] Colorado State Univ, Grad Degree Program Ecol, Nat Resource Ecol Lab, Ft Collins, CO 80523 USA
[2] Kansas State Univ, Div Biol, Manhattan, KS 66506 USA
[3] Yale Univ, Dept Ecol & Evolut Biol, New Haven, CT 06511 USA
[4] Florida Int Univ, Marine Sci Program, Dept Biol Sci, N Miami, FL 33181 USA
[5] Univ Maine, Dept Wildlife Ecol, Orono, ME 04469 USA
[6] Colorado State Univ, Coll Nat Resources, Ft Collins, CO 80523 USA
[7] Colorado State Univ, Dept Stat, Ft Collins, CO 80523 USA
[8] Univ New Mexico, Dept Biol, MSC03 2020, Albuquerque, NM 87131 USA
[9] Univ KwaZulu Natal, Sch Biol & Conservat Sci, ZA-3209 Pietermaritzburg, South Africa
[10] Kruger Natl Pk, Sci Serv, ZA-1350 Skukuza, South Africa
[11] Colorado State Univ, Dept Biol, Grad Degree Program Ecol, Ft Collins, CO 80523 USA
基金
美国国家科学基金会;
关键词
ANPP; Fire; Grasslands; Grazing; Nitrogen; Savannas; LONG-TERM; TALLGRASS PRAIRIE; RAINFALL VARIABILITY; PLANT DIVERSITY; NORTH-AMERICAN; C-4; GRASS; FIRE; NITROGEN; COMMUNITY; RESPONSES;
D O I
10.1007/s10021-009-9273-1
中图分类号
Q14 [生态学(生物生态学)];
学科分类号
071301 [植物生态学];
摘要
Patterns and controls of annual aboveground net primary productivity (ANPP) are fundamental metrics of ecosystem functioning. It is generally assumed, but rarely tested, that determinants of ANPP in one region within a biome will operate similarly throughout that biome, as long as physiognomy and climate are broadly consistent. We tested this assumption by quantifying ANPP responses to fire, grazing history, and nitrogen (N) addition in North American (NA) and South African (SA) savanna grasslands. We found that total ANPP responded in generally consistent ways to fire, grazing history, and N addition on both continents. Annual fire in both NA and SA consistently stimulated total ANPP (28-100%) relative to unburned treatments at sites with deep soils, and had no effect on ANPP in sites with shallow soils. Fire did not affect total ANPP in sites with a recent history of grazing, regardless of whether a single or a diverse suite of large herbivores was present. N addition interacted strongly and consistently with fire regime in both NA and SA. In annually burned sites that were not grazed, total ANPP was stimulated by N addition (29-39%), but there was no effect of N fertilization in the absence of fire. In contrast, responses in forb ANPP to fire and grazing were somewhat divergent across this biome. Annual fire in NA reduced forb ANPP, whereas grazing increased forb ANPP, but neither response was evident in SA. Thus, despite a consistent response in total ANPP, divergent responses in forb ANPP suggest that other aspects of community structure and ecosystem functioning differ in important ways between these mesic savanna grasslands.
引用
收藏
页码:982 / 995
页数:14
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