Sunday , August 1 2021

Research: Predictive models show weed spikes –

A new prediction model developed by an ecologist at the University of Massachusetts Amherst and a climate scientist at the University of Washington shows that climate change allows general ragweed to expand its expanding reach to the north and into the main northeastern metro area, deteriorating conditions for millions person. with fever and asthma.

Plant ecologist Kristina Stinson at UMass Amherst, who leads a research team that has been studying this plant for more than a decade – specifically how to respond to increased CO2 level – work with climate modelers and writers who fit Michael Case at UW on this project. Details appear online in the journal PLOS One.

They show that although weeds are expected to expand their range, this can be moderated by the sensitivity of the factories themselves to climate variability. For example, they note that in their analysis, rwweed was negatively correlated with the variability of very low or very high annual rainfall, "showing general sensitivity to extreme precipitation" and extreme temperatures, the authors note. Stinson added that this could be an important uncertainty; "If the Northeast becomes wetter and cooler, it will be less friendly for ragweed," he said.

"One of the reasons we chose to study ragweed was because of the implications of human health. Ragweed pollen is the main cause of allergens for symptoms of fever in the summer and fall in North America, affecting many people, "notes the plant ecology.

To better understand how climate change can affect general ragweed distribution, Stinson and Case built maximum entropy, Maxent, a predictive model using climate and bioclimatic data and observations throughout the Eastern US They used data from the Global Biodiversity Information Facility based in Denmark, a project which provides hundreds of millions of species recorded throughout the world, plus plant data from herbarium records as stored at UMass Amherst.

Stinson said, "We enlarged 700 data points for ragweed from all its reach in North America, and paired that information with other databases that determine the climate in each of the right locations. We then use the climate change model to project ahead in time what might be expected to happen. "

The authors also point out, "After building and testing our model, we then projected a general ragweed distribution in the future using a set of 13 global climate models under two future greenhouse gas scenarios for the mid and late centuries. In addition to providing geo-reference hotspots from future expansion potential, we also provide trust metrics by evaluating the number of global climate models that agree. "

This model shows the "substantial contraction" of general ragweed can be imagined in central Florida, the southern Appalachia Mountains and northeast Virginia, along with potential areas of expansion in the current northern margin of distribution, especially in the northeastern US.

Stinson added, "What I consider quite interesting is not so much that the variety of ragweed will develop, because that is what might be expected for thin species, but I am interested to see where the spread is likely and where we might see the range of contractions. there will be temporary bursts followed by contractions in the 2070s. "

The researchers point out, "Although other factors and modeling approaches must be explored, we offer an initial view of where general ragweed might be a new concern in the future. Due to the health effects of ragweed, local weed control boards may be advised to monitor expansion areas and potentially increase eradication efforts. "

Stinson points out, "We don't have many models like this that tell where individual species can be under different scenarios. Ecologists are conducting this kind of research for more species, but there are not always enough data points from around the world; data on individual species is rare. But ragweed is very abundant, which makes this research feasible. "

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