Bruce Byers, an independent scientist who runs the business Bruce Byers Consulting, made a surprising discovery on fossilized wood his dad and he had found decades ago when hiking in the Bears Ears in southeastern Utah. When his father was moving, he required the fossil, a cross-section of a petrified log from the Chinle formation that dates to about 210 million years ago–the taxonomy of such wood is somewhat contentious, with some lumping and some splitting, but the trees were long thought to be all one species, Agathoxylon arizonicum, a type of conifer. Between the fossil’s finding and its reacquisition, he had learned more about dendrochronology and fire scars, and he realized that the fossil appeared to have a fire scar. He took it to a stone-cutter with specialized tools for finely slicing the cross-section to better observe the cellular structure of the fossilized wood. In his talk, Byers presented the evidence that the tree had experienced fire: The telltale damage in the cambium and response of growth curving around the wound, compressed tracheids away from the scar in the same tree ring associated with the fire scar, and post-fire growth release, demonstrated by larger tracheids after the fire than before. During the Triassic, these trees were tropical and did not experience annual seasons, so growth rings were not annual. But the tracheids hold many clues to this tree’s past.
Byers said that when he first contacted paleobotanists about his observations that they didn’t know what a fire scar looked like, and he wondered whether the lack of overlap between paleobotany and dendrochronology could explain why these attributes when unnoticed for so long in a well known fossil formation. He returned to Utah to look for more examples, and after sifting through hundreds, he found 13 specimens that may show fire scars (but need to be confirmed with further study). This discovery is the earliest fire scar known to date, and he announced it in a paper published last month in Palaeogeography, Palaeoclimatology, and Palaeoecology. Byers speculated that perhaps adaptation to fire in trees may have started in the Triassic. There are many possible avenues of research left: He is now examining microscopic features and other aspects of the fire scarred fossils.
Terrence McGlynn, who blogs at Small Pond Science, is working on better predicting number and diversity of ant species at a spatial scale of a square meter in tropical rainforests (La Selva, Costa Rica). He noted that at the landscape or regional scale, biologists can predict where and how ants occur, but not at the mesoscale. He posits that the time and place of sun flecks on the forest floor predicts which ant species are where. The ants he studies move their colony about every three weeks. A sun fleck, even though it might only last a few minutes in a day, will show up roughly in the same spot for a few weeks. He did an experiment with a control and three treatments that had the same amount of shade but distributed differently: coarse regular, fine regular, or fine random. The two regularly distributed shades, one coarse and the other fine, had two times the number of species than the control or random fine shade. He thought this might be because the coarse and regular fine shade were both predictable patterns, and that perhaps spatial grain did not matter, at least for the grains he used. He’s not sure why he got these results, but he thought maybe if many species liked to live on the boundary between sun and shade, the regular patterns would be more attractive.
I also went to the Ignite talks by authors on different chapters of the National Climate Assessment. Peter Groffman of the Cary Institute of Ecosystem Studies kicked it off, making five main points: (1) Water scarcity is a risk in light of climate change; (2) Extreme events are a concern, especially in locations that have deteriorated their coastal features, such as dunes and wetlands; (3) Plants and animals will respond to climate change in many different ways. Some will be good (“I’m looking forward to growing bananas in New York.”); others will be bad, for example the growing population of ticks and the growing problem of tick-borne diseases; (4) Seasonal patterns are changing and will continue to do so. For example, in the mountains of New Hampshire, ice cover on Muir Lake is declining each winter and snow melt is earlier. (5) We need to understand and monitor adaptive processes. Groffman pointed out that the NCA is an ongoing process and climate models are an ongoing process. Each year, we have new opportunities to ask “What did we get wrong and what did we get right?” Then, predictability and understanding are refined. The science of climate change is constantly improving.
Nancy Grimm spoke about how important the perspective of ecosystem services is to the discussion around climate change responses: “Threats to ecosystems are threats to people.”
Laura Petes spoke about coastal zone development. She mentioned the town of Hoboken, NY, winner of the Rebuild by Design competition, as a case study of smart response to the risks of sea level rise.
Linda Joyce spoke about the effects of increasing growing season, wildfires, and pest outbreaks on forests, and how this could impact wood production and recreation.
Julie Maldonado discussed the effects of climate change on indigenous lands and cultures, including loss of traditional knowledge, water and food availability, and relocation as land changes, for example in areas experience ice loss and permafrost thaw.
Kim Knowlton of NRDC declared that climate change threatens health, here and now. She said, “Heat can be lethal,” mentioning Chicago’s heatwave in 1995, where so many people died at once (750 people) that the morgues were overloaded and the dead had to be stored in refrigerator trucks. Such heat waves are becoming more common. She also noted that air pollution worsens when temperatures rise and that the ragweed pollen production season is now 2 to 3 weeks longer. Also, she said that pathogens are shifting ranges and increasing in areas where they used to not be found: For example, the number of Vibrio infections has increased. She then pointed out that early actions prevent human suffering–800,000 people were displaced by Katrina, and people need to be better prepared for such catastrophes. She then pointed out that the biggest sector in the US that generates greenhouse gases is power plants, and that reducing emissions there would be a good starting place.
Richard Grojahn of UC Davis, who is also a pistachio farmer, spoke about climate change’s effects on agriculture. California, as the #1 agricultural producer in the US, is going to be an important player as temperatures rise and droughts become more frequent. He noted that agriculture in CA depends on irrigation, and as temperatures increase, farmers pour on more water to deal with it. Groundwater levels in CA are declining, and pests are slated to increase. “Droughts come and go, but people want to eat all the time,” he said.
Averyt Kristen spoke about the energy-water nexus and made the point that “low carbon is not necessarily low water.” For example, she noted that switching from coal to solar or nuclear power generation does not help water scarcity–even though that may seem nonintuitive. Where your water utility gets its energy affects water and energy use. She noted that desalination in particular is an incredibly energy intensive process. She finished saying that there are opportunities around this nexus: Solutions to these problems could be incredibly profitable.
Joel Smith spoke about how managers of ecosystems are planning for climate change, even in light of limited support.
Melissa Kenney of University of Maryland ended the session talking about the National Climate Indicators System.