Climate change – who can keep up?

Evolution has no forethought. An artic fox turns white at a particular time in winter due to the selection pressures experienced by its ancestors. This adaptation helped foxes in the past blend into the snowy background and more easily disguise themselves from prey. But what if timing of first snowfall starts to move later and later into the year or becomes more unpredictable? This is a question of phenology, the timing periodic plant and animal life cycle events and how these are influenced by seasonal and climate variations. Will the evolution of artic fox fur keep up with the changes in snowfall timing each year?

Long term data sets are the best way to see evidence of climate change in the phenology of plants and animals. Historic photos from Lowell Cemetery in MA show bare branches, while 137 years later the plants have already leafed out for the spring.

Long term data sets are the best way to see evidence of climate change in the phenology of plants and animals. Historic photos from Lowell Cemetery in MA show bare branches, while 137 years later the plants have already leafed out for the spring.

With climate change, there will be phenology winners and losers – those that can respond, and those that cannot and may go locally extinct. Not only do species have to deal with a shifting climate, but they will also have to respond to phenology changes in the community around them. A particular plant may respond faster to climate change than its neighbors, greening up earlier in the season, potentially giving it a competitive advantage.

Invasive species may be among the winners. Invasives are predicted to have greater capacity to evolve quickly (think many genotypes coming together in one population) and may be more amenable to drastic changes in their habitat compared to natives – they did manage to invade a new habitat, after all. If invasive species can shift their phenology more than native plants, this may give them an even greater dominance over natives.

What they did: In the study by Calinger, Queenborough, and Curtis (2013), they used Ohio herbarium records and historical climate data to determine how 141 species of plants are responding to climate change. From the herbarium records, they collected information on date of peak flowering time for each species. For the analysis, they grouped plants into several functional groups including: season of flowering, pollination type (wind, insect), origin (native, non-native), and growth form (woody, herbaceous, annual, etc.).

What they found: Of the 141 species, 66 species advanced their peak flowering date in response to the 0.9°C temperature increase for the area since 1895. Non-native species responded almost twice as strongly as did native species, advancing flowering time by 2.8 days compared to native’s 1.5-day response. Herbaceous annuals that flowered in the spring, and species that are wind pollinated responded most strongly.

Why it’s cool: This paper shows very convincingly that climate change is altering the composition of plant communities – some plants species in the study were found to be flowering 3 weeks earlier, while some showed no change. Further, their findings can be used in a predictive way and help conservationists predict which species might be harmed most my climate change. This paper leaves me thinking about invasive species and their potential to get even worse as natives become stressed by climate change and invasives respond quickly.

The next steps will be to experimentally test whether those species that respond more to climate change are actually being facilitated by climate change. For example, if invasives species green up faster than natives, does this give them an increased competitive advantage, leading to increased fitness?

 

Calinger, K.M., S. Queenborough, and P.S. Curtis (2013). Herbarium specimens reveal the footprint of climate change on flowering trends across north-central North America. Ecology Letters 16(8): 1037-1044
Elizabeth Schultheis

About Elizabeth Schultheis

I have always been fascinated by invasive species and their ability to outcompete native species while taking over and transforming habitats. The number of invasive species is growing year-by-year, as plants, animals, and microbes are introduced into habitats where they did not historically occur. Invasive species are often destructive, costing billions in damages to native ecosystems and human interests around the world annually. Yet, despite all the problems they cause, we still do not know what causes some species to be invasive and not others. My research addresses this question by testing whether invasive species are those that are not strongly controlled by competitors, predators, and herbivores outside their native range. That is, they are successful invaders because they have left their natural enemies behind.
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