If you thought that the predictions on the effects of climate change were off-base, it turns out you were right. Only not in the way you may have hoped. A new study calls into question current understanding of the effects of climate change on plant species. Scientists assert that experimental models may need to be reevaluated if they aim to predict the actual effects of warming on phenology, that is, the timing of seasonal responses. The study was carried out by analyzing long-term observational records as well as the data from experimental models on multiple continents and on over 1,600 plant species. The findings indicate that experimental models “don’t line up with the long term data, and in fact they greatly underestimate how much plants change their leafing and flowering with warming,” ecologist Elizabeth Wolkovich told BBC News.

Researchers found that observational data recorded plants flowering at a rate that was over 8x faster than experimental models projected, and leafing at a rate that was 4x faster. Since experimental models are widely used to predict the responses that climate change will elicit in plant species, the scientists who participated in this interdisciplinary study are cautioning against the soundness of such predictions. They feel this discrepancy has widespread implications.

“The bottom line is that the impacts might be bigger than we have believed until now. That’s going to provoke a lot of work to probably revise modeling results for estimations of what’s going to happen in the future for food production especially,” noted Dr. This Rutishauser from the Climate Change Research at the University of Bern in Switzerland. Other concerns include our understanding of loss of biodiversity as well as loss of fresh water supplies.

Twenty-two institutions in five different countries participated in the analysis, and they concluded that experimental design needs to be carefully monitored, and stressed the importance of both the collection and examination of observational data. Dr. Elizabeth Wolkovich even made an appeal to the public, “We have very few monitoring networks. We need many, many people out there observing this because it is changing faster and across more habitats than we are currently measuring – we need more help!”

Last month, a New York Times article similarly discussed the importance of our recorded data in understanding responses to climate change. The article highlighted how examining the historical datasets from Thoreau and other early naturalists can give us insight into how plant communities have changed over time and may continue to. Given that it is now 5 degrees warmer at the observational sites than it was in the 1850s, monitoring the flora can illuminate how warming has affected them. An excerpt from the article reads, “Some species are changing faster, some slower, but the changes matter…Species will have to adjust or perish. No doubt, there will be — and already are — winners and losers in this great shake-up.”

Studies carried out on the flora surrounding Thoreau’s famous Walden Pond have indicated exactly which plants are the winners and which are the losers. A 2008 study found that due to climate change, many of the native species Thoreau recorded are no longer present. In fact, it is estimated that from a quarter to a third of the plant species documented by him have disappeared, and many others are now endangered. To make matters worse, in 2010 another study conducted on the area concluded that invasive species (which have been implicated in biodiversity loss) benefited from the warmth with a head start on the growing season which gave them a competitive advantage, and thus their spread is ever-increasing as temperatures rise.

Perhaps you have observed the very same changes in the flora and phenology where you live. Locally, those seeking to find New Jersey’s wildflowers noted that many species came into their prime much ahead of schedule. This year Mayapples would have been more appropriately called “Aprilapples”. As warming trends continue, the earlier bloom time may become the new norm.

Aprilapple? (c) 2012 Belinda Beetham

If you are interested in contributing to the much-needed data on changes of seasonal response in plant and animal species, consider participating in the National Phenology Network’s online database, Nature’s Notebook.  Once you create an account, you can register the location you plan to collect observations for, and begin reporting them directly online. They have even created an app for smart phones to make data entry easier. This data can aid scientists in obtaining a clearer picture of the actual effects of climate change, an effort that is increasingly important in the understanding of our future.

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