Abstract Detail

Phenology and Conservation Implications

Montgomery, Rebecca [1], Reich, Peter [2], Rich, Roy [2], Stefanski, Artur [2], Schwartzberg, Ezra [3], Lindroth, Rick [4], Raffa, Ken [5].

Plant phenological responses to experimental warming at the temperate-boreal ecotone.

Climate is a major driver determining the location of biome boundaries worldwide. Such ecotones often encompass the range boundaries of more broadly distributed species. In northeastern MN, the southern boreal forest meets the eastern deciduous forest with numerous species at either their northern or southern range limits. Based solely on climate envelope models, many of the species found in this region are considered likely to change during the 21^st century leading to decline or increase in abundance, and contraction or extension their range. Yet little information exists to evaluate the validity of such predictions or the mechanisms that might underlie such changes. Here, we present results that suggest the potential for major alterations in phenology associated with +1.8 and +3.6 C warming. We warmed small plots using infrared heat lamps and resistance cables buried in the soil. In general, for seedlings of five boreal and five temperate tree species, warming caused earlier leaf out in spring and later leaf senescence in fall, extending the photosynthetic growing season for all species by ~10 and ~20 days on average for +1.8 C and +3.6 C warming, respectively. Changes of 10-20 days in the "leaf on" period could have substantial positive impacts on annual gross primary production and possibly net ecosystem exchange. However, in some species the extension of the growing season may not lead to higher productivity. We found that despite earlier leafing, boreal conifers had significantly lower shoot growth. In addition, we found that changes in leafing phenology of trembling aspen (Populus tremuloides) caused increased synchrony with a defoliating insect herbivore. Lastly, we found a broad range of phenological responses in the understory plant community. Better data on phenological responses at the population and community level as well as elucidation of species-specific environmental cues for phenology will further our understanding of the consequences of phenological shifts for ecological processes now and in the future.

Broader Impacts:

1 - University Of Minnesota, 1530 Cleveland Ave N., GREEN HALL 115, St. Paul, MN, 55108, USA
2 - University of Minnesota, Department of Forest Resources, 1530 Cleveland Ave N., 115 Green Hall, St. Paul, MN, 55108, USA
3 - University of Wisconsin-Madison, Department of Entomology, 1630 Linden Drive, Madison, WI, 53706, USA
4 - University of Wisconsin-Madison, Department of Entomology, 1630 Linden Drive, Madison, WI, 55108, USA
5 - University of Wisconsin-Madison, Department of Forest Resources, 1630 Linden Drive, St. Paul, MN, 55108, USA

Keywords:
none specified

Presentation Type: Symposium or Colloquium Presentation
Session: C7
Location: Union C/Hyatt
Date: Wednesday, July 11th, 2012
Time: 1:30 PM
Number: C7001
Abstract ID:913