Response of grassland biomass production to simulated climate change and clipping along an elevation gradient

Changes in rainfall and temperature regimes are altering plant productivity in grasslands worldwide, and these climate change factors are likely to interact with grassland disturbances, particularly grazing. Understanding how plant production responds to both climate change and defoliation, and how this response varies among grassland types, is important for the long-term sustainability of grasslands. For 4 years, we manipulated temperature [ambient and increased using open-top chambers (OTC)], water (ambient, reduced using rainout shelters and increased using hand watering) and defoliation (clipped, and unclipped) in three grassland types along an elevation gradient. We monitored plant cover and biomass and found that OTC reduced biomass by 15 %, but clipping and water treatments interacted with each other and their effects varied in different grassland types. For example, total biomass did not decline in the higher elevation grasslands due to clipping, and water addition mitigated the effects of clipping on subordinate grasses in the lower grasslands. The response of total biomass was driven by dominant plant species while subordinate grasses and forbs showed more variable responses. Overall, our results demonstrate that biomass in the highest elevation grassland was least effected by the treatments and the response of biomass tended to be dependent on interactions between climate change treatments and defoliation. Together, the results suggest that ecosystem function of these grasslands under altered climate patterns will be dependent on site-specific management.

[1]  O. Hoegh‐Guldberg,et al.  Ecological responses to recent climate change , 2002, Nature.

[2]  John Harte,et al.  Experimental warming, not grazing, decreases rangeland quality on the Tibetan Plateau. , 2007, Ecological applications : a publication of the Ecological Society of America.

[3]  J. Connell.  Diversity in tropical rain forests and coral reefs. , 1978, Science.

[4]  John Harte,et al.  Experimental warming causes large and rapid species loss, dampened by simulated grazing, on the Tibetan Plateau , 2004 .

[5]  Vincent R. Gray.  Climate Change 2007: The Physical Science Basis Summary for Policymakers , 2007 .

[6]  L. Fraser,et al.  Tracking Soil Temperature and Moisture in a Multi-Factor Climate Experiment in Temperate Grassland: Do Climate Manipulation Methods Produce their Intended Effects? , 2011, Ecosystems.

[7]  S. Carpenter,et al.  Stability and Diversity of Ecosystems , 2007, Science.

[8]  Corinne Le Quéré,et al.  Climate Change 2013: The Physical Science Basis , 2013 .

[9]  Paul A. Keddy,et al.  Working with Heterogeneity: An Operator’s Guide to Environmental Gradients , 1991 .

[10]  Philip E. Hulme,et al.  Adapting to climate change: is there scope for ecological management in the face of a global threat? , 2005 .

[11]  R Core Team,et al.  R: A language and environment for statistical computing. , 2014 .

[12]  J. Lovett-Doust,et al.  Plant strategies, vegetation processes, and ecosystem properties , 2002 .

[13]  W. Voigt,et al.  Using functional groups to investigate community response to environmental changes: two grassland case studies , 2007 .

[14]  D. Tilman.  Causes, consequences and ethics of biodiversity , 2000, Nature.

[15]  Climate change experiments in temperate grasslands: synthesis and future directions , 2012, Biology Letters.

[16]  Steven F. Oberbauer,et al.  Plant community responses to experimental warming across the tundra biome , 2006, Proceedings of the National Academy of Sciences of the United States of America.

[17]  A. L. V. Ryswyk,et al.  THE CLIMATE, NATIVE VEGETATION, AND SOILS OF SOME GRASSLANDS AT DIFFERENT ELEVATIONS IN BRITISH COLUMBIA , 1966 .

[18]  S. Collins,et al.  A framework for assessing ecosystem dynamics in response to chronic resource alterations induced by global change. , 2009, Ecology.

[19]  N. Buchmann,et al.  Response of temperate grasslands at different altitudes to simulated summer drought differed but scaled with annual precipitation. , 2009 .

[20]  Roberta E. Martin,et al.  GRAZING SYSTEMS, ECOSYSTEM RESPONSES, AND GLOBAL CHANGE , 2004 .

[21]  J. P. Grime,et al.  The response of two contrasting limestone grasslands to simulated climate change. , 2000, Science.

[22]  D. Gayton.  Native and non-native plant species in grazed grasslands of British Columbia's southern interior , 2004, Journal of Ecosystems and Management.

[23]  O. Edenhofer,et al.  Mitigation from a cross-sectoral perspective , 2007 .

[24]  K. McCann.  The diversity–stability debate , 2000, Nature.

[25]  J. Zak,et al.  Assessing the Response of Terrestrial Ecosystems to Potential Changes in Precipitation , 2003 .

[26]  K. Havstad,et al.  Mongolia's rangelands: is livestock production the key to the future? , 2008 .

[27]  Stefan Sperlich,et al.  Explaining grassland biomass – the contribution of climate, species and functional diversity depends on fertilization and mowing frequency , 2011 .

[28]  J. P. Grime,et al.  Benefits of plant diversity to ecosystems: immediate, filter and founder effects , 1998 .

[29]  G. Henry,et al.  Increased plant biomass in a High Arctic heath community from 1981 to 2008. , 2009, Ecology.

[30]  Scott D. Wilson,et al.  Semiarid grassland responses to short-term variation in water availability , 2004, Plant Ecology.

[31]  E. Tisdale.  The Grasslands of the Southern Interior of British Columbia , 1947 .

[32]  C. Rosenzweig,et al.  Attributing physical and biological impacts to anthropogenic climate change , 2008, Nature.

[33]  James H. Brown,et al.  Reorganization of an arid ecosystem in response to recent climate change. , 1997, Proceedings of the National Academy of Sciences of the United States of America.

[34]  J. Blair,et al.  Contingent productivity responses to more extreme rainfall regimes across a grassland biome , 2009 .

[35]  F. Woodward,et al.  Global response of terrestrial ecosystem structure and function to CO2 and climate change: results from six dynamic global vegetation models , 2001 .

[36]  C. Dormann,et al.  Climate change in the Arctic: using plant functional types in a meta‐analysis of field experiments , 2002 .

[37]  L. Fraser,et al.  Adaptive phenotypic plasticity of Pseudoroegneria spicata: response of stomatal density, leaf area and biomass to changes in water supply and increased temperature. , 2009, Annals of botany.

[38]  J. Peñuelas,et al.  Responses of terrestrial ecosystems to temperature and precipitation change: a meta‐analysis of experimental manipulation , 2011 .

[39]  A. Knapp,et al.  Intra‐seasonal precipitation patterns and above‐ground productivity in three perennial grasslands , 2007 .

[40]  K. Klanderud.  Climate change effects on species interactions in an alpine plant community , 2005 .

[41]  Maosheng Zhao,et al.  Drought-Induced Reduction in Global Terrestrial Net Primary Production from 2000 Through 2009 , 2010, Science.

[42]  E. Post,et al.  Opposing plant community responses to warming with and without herbivores , 2008, Proceedings of the National Academy of Sciences.

[43]  John Harte,et al.  INTEGRATING EXPERIMENTAL AND GRADIENT METHODS IN ECOLOGICAL CLIMATE CHANGE RESEARCH , 2004 .

[44]  Richard W. Lucas,et al.  Using rainout shelters to evaluate climate change effects on the demography of Cryptantha flava , 2008 .

[45]  M. Power,et al.  Species Interactions Reverse Grassland Responses to Changing Climate , 2007, Science.

[46]  J. Blair,et al.  Rainfall variability has minimal effects on grassland recovery from repeated grazing , 2014 .

[47]  G. Henry,et al.  Open‐top designs for manipulating field temperature in high‐latitude ecosystems , 1997 .

[48]  A. Classen,et al.  Climate change effects on plant biomass alter dominance patterns and community evenness in an experimental old‐field ecosystem , 2010 .

[49]  J. Bascompte,et al.  Global change and species interactions in terrestrial ecosystems. , 2008, Ecology letters.