Abstract Detail

The Hills are Alive: Ecology and Evolution of the Intermountain West Flora

Emery, Nancy [1].

Alpine plant responses to climate variation: long-term trends and experimental insights from the Niwot Ridge LTER.

Perched above treeline along the most extensive mountain range in North America, the Rocky Mountain tundra is one the most climatically extreme ecosystems occupied by plants on the planet. Adapted to long, cold winters, shallow soils, and short growing seasons, alpine plants are expected to be particularly vulnerable to climate change. High levels of spatial and temporal heterogeneity across complex terrain can moderate the exposure of alpine plants to different climate drivers, while functional diversity and life history variation may shape plant responsiveness to climate variability. The Niwot Ridge Long-Term Ecological Research (LTER) project in the Southern Rockies of central Colorado has been monitoring environmental drivers of alpine plant community dynamics for over 40 years with the goal of understanding when, where, and how alpine vegetation responds to climate variation. In this high-elevation mountain system, rising temperatures change the timing, magnitude, and distribution of snow, energy, and growing-season moisture across the landscape. Furthermore, correlations among climate variables have decoupled over time, generating potentially novel combinations of climate axes that resident plants have only recently started experiencing. In addition to monitoring long-term trends in climate and plant community composition, researchers at the Niwot Ridge LTER are conducting experimental studies that tease apart the effects of temperature, snowpack, snowmelt timing, and soil moisture on plant community structure, population dynamics, and individual-level phenology and recruitment. Recent results indicate that the timing of snowmelt - which is determined largely by snowpack, slope, aspect, and wind exposure - is the critical cue for alpine plant phenology, driving the timing of each growth stage (green-up, flowering, and senescence) and the overall length of the growing season, while also regulating community composition and productivity. The amount and distribution of soil moisture, generated by melting snow and summer precipitation, is an important predictor of plant distribution patterns and functional trait variation across the alpine landscape at Niwot Ridge. Snowpack is one of several factors associated with shrub expansion, and shrubs foster microclimates that have additional effects on seedling emergence and survival. Collectively, previous and ongoing work at Niwot Ridge identifies snowpack and snowmelt timing as key drivers of plant dynamics in this alpine ecosystem while providing a particularly striking example of how fine-scale heterogeneity can moderate plant responses to climate variation.

1 - University Of Colorado Boulder, Ecology And Evolutionary Biology, Campus Box 334, University Of Colorado, Boulder, CO, 80309, United States

Keywords:
Rocky Mountains
alpine
Niwot Ridge
LTER
climate change
phenology
tundra
long-term research.

Presentation Type: Symposium Presentation
Session: SY5, The Hills are Alive: Ecology and Evolution of the Intermountain West Flora
Location: /
Date: Thursday, July 22nd, 2021
Time: 10:15 AM(EDT)
Number: SY5002
Abstract ID:554
Candidate for Awards:None