Our recent fieldwork posed interesting questions about climate change and its effects on the growing infestation of Melilotus albus (white sweetclover) and Vicia cracca (bird vetch) to the north of the Yukon River in Alaska. It was once thought that white sweetclover would not be capable of spreading as far north as the Arctic Circle, but recent infestation throughout the Dalton Highway Corridor Management Area (BLM) suggest that the plant is capable of adapting to the extreme conditions.

After a record late spring with temperatures well below zero until late April, the infestation appears to have been reduced significantly in comparison to observations in past years. Reviewing the literature lead me to make the following hypotheses:

• The temperatures in both winter 2012-2013 and spring 2013 may have had an effect on spring phenology (Yu et al. 2010)
• Dormancy may have been broken and seeds made “sensitive” to germination and as a result of environmental conditions such as fluctuating temperatures (Baskin and Baskin 2008); winter emergence has been observed as light is not required for germination (cite)
• Cloudy, wet weather in summer 2012 may have decreased pollinator activity (Bare 1979)
• It may not be a “sweetclover year” or a “boom year” (Van Riper and Larson 2009)
• Large fluctuations in sweetclover cover complicate interpretation of seral change along a chronosequence difficult (Gucker 2009)
• Vicia cracca along river crossings may have been reduced by consistent manual removal efforts

Our plan to conduct a formal inventory of both infestations may be delayed due to the fact that the assessment is unlikely to produce a representative data set. An informal assessment is underway and we are using the data to implement plans for manual, mechanical and chemical treatments.

This raises many interesting research questions about the need for intensive management techniques such as chemicals. If this is just an off-year, that is one thing, but if the extreme climate is capable of influencing a significant die-back, perhaps it is not worth the risk that chemicals pose to the surrounding ecosystem. Another interesting question is whether or not either plant is capable of interfering with native vegetation outside of the corridor.

Furthermore, there is a strong social component to this control effort. The emotional reaction towards invasive weeds is strong in Alaska. Pristine wilderness in the arctic is vulnerable to such perturbations in that it is sensitive to exposure to change. Therefore, local conservationists are persistent in their efforts to contribute to the manual removal of these plants along waterways to prevent the spread into adjacent wilderness areas. It is hard to say without further research whether the high level of concern and community commitment is “worthwhile”, meaning 1) whether or not it is effective and 2) whether or not the risk warrants the effort.

I am intrigued by this opportunity to delve into the research necessary to develop a comprehensive social-ecological management plan under such high levels of uncertainty. The data we collect will help to inform decision-making in the coming years and will hopefully lead to effective and efficient management strategies.