Weather - Climate - Plants
Can we use mountain plants as indicators of climate change?
Mountain plants have several adaptations for a cold climate and thrive within a range of annual temperatures. Worldwide, temperatures have risen by more than 1°F over the past 40 years and are predicted to rise by 4–10°F over the next century. Precipitation patterns have also changed – some places are receiving more rain than they did in the past, some places less.
Climate change is already impacting plants and altering the structure of plant communities. Species that are particularly vulnerable to climate change include those with limited ranges and dispersal abilities. For example, Robbins’ cinquefoil, a rare alpine plant found in only two locations in the White Mountains. Like many alpine specialists, the Robbins’ cinquefoil is a poor competitor when crowded, but has adapted to withstand the extreme conditions of alpine peaks. Unfortunately for these alpine species, temperatures are warming. In particular for the Robbins’ cinquefoil, winter temperatures in New Hampshire have warmed more than 3°F over the past century, faster than in other regions, according to the New England Regional Assessment Group’s 2001 report. As temperatures warm, the conditions atop mountain peaks will become less harsh, allowing species formerly limited to lower altitudes to migrate to higher elevations. With no way to migrate northward, the Robbins’ cinquefoil and many other alpine plants will be likely to occupy ever smaller areas on mountains until they are pushed into extinction.
Models and evidence from historical plant migrations (e.g. those that occurred at the end of previous ice ages) suggest that although some species will likely migrate to areas with appropriate climates, many plant species will not be able to migrate fast enough to keep pace with current rates of warming.
Many plant species are also responding to climate change by advancing the onset of leaf burst, flowering, and fruiting, and delaying leaf drop. The growing season is lengthening. The earlier onset of bud burst, flowering, and fruiting could have major impacts on timing-sensitive relationships with pollinators, seed dispersers, and herbivores. Events that have long occurred in synchrony may become decoupled, which could especially impact plant species with specialized pollinators and seed dispersers.
Sources: Climate Change and Plant Conservation, by Abraham J. Miller-Rushing and Richard B. Primack
