Biological consequences of earlier snowmelt from desert dust deposition in alpine landscapes

Dust deposition to mountain snow cover, which has increased since the late 19th century, accelerates the rate of snowmelt by increasing the solar radiation absorbed by the snowpack. Snowmelt occurs earlier, but is decoupled from seasonal warming. Climate warming advances the timing of snowmelt and early season phenological events (e.g., the onset of greening and flowering); however, earlier snowmelt without warmer temperatures may have a different effect on phenology. Here, we report the results of a set of snowmelt manipulations in which radiation-absorbing fabric and the addition and removal of dust from the surface of the snowpack advanced or delayed snowmelt in the alpine tundra. These changes in the timing of snowmelt were superimposed on a system where the timing of snowmelt varies with topography and has been affected by increased dust loading. At the community level, phenology exhibited a threshold response to the timing of snowmelt. Greening and flowering were delayed before seasonal warming, after which there was a linear relationship between the date of snowmelt and the timing of phenological events. Consequently, the effects of earlier snowmelt on phenology differed in relation to topography, which resulted in increasing synchronicity in phenology across the alpine landscape with increasingly earlier snowmelt. The consequences of earlier snowmelt from increased dust deposition differ from climate warming and include delayed phenology, leading to synchronized growth and flowering across the landscape and the opportunity for altered species interactions, landscape-scale gene flow via pollination, and nutrient cycling.

[1]  C. Körner,et al.  The Role of Photoperiodism in Alpine Plant Development , 2003 .

[2]  Christopher B. Field,et al.  Diverse responses of phenology to global changes in a grassland ecosystem , 2006, Proceedings of the National Academy of Sciences.

[3]  Robert D. Hollister,et al.  PLANT RESPONSE TO TEMPERATURE IN NORTHERN ALASKA: IMPLICATIONS FOR PREDICTING VEGETATION CHANGE , 2005 .

[4]  A. Fitter,et al.  Spatial and temporal patterns of growth and nutrient uptake of five co-existing grasses , 1984 .

[5]  C. Moulin,et al.  Impact of human‐induced desertification on the intensification of Sahel dust emission and export over the last decades , 2006 .

[6]  M. H. Jones,et al.  Long-term experimental manipulation of winter snow regime and summer temperature in arctic and alpine tundra , 1999 .

[7]  W. D. Billings,et al.  An Alpine Snowbank Environment and Its Effects on Vegetation, Plant Development, and Productivity , 1959 .

[8]  P. Shi,et al.  Wind erodibility of major soils in the farming-pastoral ecotone of China , 2007 .

[9]  Candace Galen,et al.  RESPONSES OF SNOWBED PLANT SPECIES TO CHANGES IN GROWING-SEASON LENGTH' , 1995 .

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

[11]  David R. Anderson,et al.  Model selection and inference : a practical information-theoretic approach , 2000 .

[12]  R. T. Ward,et al.  Phenology of Alpine Plants in Northern Colorado , 1965 .

[13]  J. Overpeck,et al.  Increasing Eolian Dust Deposition in the Western United States Linked to Human Activity , 2008 .

[14]  C. Wessman,et al.  Long-term studies of snow-vegetation interactions , 1993 .

[15]  Richard B Primack,et al.  Global warming and flowering times in Thoreau's Concord: a community perspective. , 2008, Ecology.

[16]  M. V. Price,et al.  EFFECTS OF EXPERIMENTAL WARMING ON PLANT REPRODUCTIVE PHENOLOGY IN A SUBALPINE MEADOW , 1998 .

[17]  D. Inouye,et al.  Effects of climate change on phenology, frost damage, and floral abundance of montane wildflowers. , 2008, Ecology.

[18]  S. Wipf,et al.  Advanced snowmelt causes shift towards positive neighbour interactions in a subarctic tundra community , 2006 .

[19]  U. Molau,et al.  Ecology of Alpine Snowbeds and the Impact of Global Change , 2007 .

[20]  Peter M. Vitousek,et al.  Effects of plant composition and diversity on nutrient cycling , 1998 .

[21]  E. Post,et al.  Phenological sequences reveal aggregate life history response to climatic warming. , 2008, Ecology.

[22]  Philip J. Rasch,et al.  Present-day climate forcing and response from black carbon in snow , 2006 .

[23]  D. Hooper.  THE ROLE OF COMPLEMENTARITY AND COMPETITION IN ECOSYSTEM RESPONSES TO VARIATION IN PLANT DIVERSITY , 1998 .

[24]  B. Rathcke,et al.  Phenological Patterns of Terrestrial Plants , 1985 .

[25]  R. Monson,et al.  LINKS BETWEEN MICROBIAL POPULATION DYNAMICS AND NITROGEN AVAILABILITY IN AN ALPINE ECOSYSTEM , 1999 .

[26]  M. D. Walker,et al.  Effects of interannual climate variation on phenology and growth of two alpine forbs , 1995 .

[27]  J. Schimel,et al.  Increased snow depth affects microbial activity and nitrogen mineralization in two Arctic tundra communities , 2004 .

[28]  Dan Tarpley,et al.  Diverse responses of vegetation phenology to a warming climate , 2007 .

[29]  J. McConnell,et al.  20th-Century doubling in dust archived in an Antarctic Peninsula ice core parallels climate change and desertification in South America , 2007, Proceedings of the National Academy of Sciences.

[30]  David R. Anderson,et al.  Model selection and multimodel inference : a practical information-theoretic approach , 2003 .

[31]  Eric Post,et al.  Warming, plant phenology and the spatial dimension of trophic mismatch for large herbivores , 2008, Proceedings of the Royal Society B: Biological Sciences.

[32]  T. Painter,et al.  Impact of disturbed desert soils on duration of mountain snow cover , 2007 .

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

[34]  U. Molau,et al.  Onset of flowering and climate variability in an alpine landscape: a 10-year study from Swedish Lapland. , 2005, American journal of botany.

[35]  P. Diggle,et al.  Preformation, architectural complexity, and developmental flexibility in Acomastylis rossii (Rosaceae). , 2001, American journal of botany.

[36]  A. McGuire,et al.  Effects of snowpack on timing and abundance of flowering in Delphinium nelsonii (Ranunculaceae) : implications for climate change , 1991 .

[37]  Tony Waltham,et al.  The demise of the Aral Sea – an environmental disaster , 2001 .

[38]  Thompson,et al.  A high-resolution millennial record of the south asian monsoon from himalayan ice cores , 2000, Science.

[39]  Matthew Sturm,et al.  How alpine plant growth is linked to snow cover and climate variability , 2008 .

[40]  Yiqi Luo,et al.  Divergence of reproductive phenology under climate warming , 2007, Proceedings of the National Academy of Sciences.

[41]  John Harte,et al.  SUBALPINE MEADOW FLOWERING PHENOLOGY RESPONSES TO CLIMATE CHANGE: INTEGRATING EXPERIMENTAL AND GRADIENT METHODS , 2003 .

[42]  W. Bowman,et al.  The Landscape Continuum: A Model for High-Elevation Ecosystems , 2004 .

[43]  G. Kudo,et al.  Habitat-specific responses in the flowering phenology and seed set of alpine plants to climate variation: implications for global-change impacts , 2005, Population Ecology.

[44]  K. Stinson.  Natural selection favors rapid reproductive phenology in Potentilla pulcherrima (Rosaceae) at opposite ends of a subalpine snowmelt gradient. , 2004, American journal of botany.