Katherine Eagleson


I live at 6,800 feet in altitude. Last year many of us enjoyed fruit from our trees and shrubs for the first time in several years. A cool spring delayed blossom eruption until temperatures warmed beyond hard-frost likelihood. It will not be a repeated pleasure this year. In late April temperatures in the teens eliminated any hope of fruit developing from bulging buds. Broad-tailed and black-throated hummingbirds are mobbing my feeders. There are very few flowers. Bees are coming to hummingbird feeders. There are very few flowers. A combination of extended drought and late spring freezes has taken a big toll on flowering plants. Whenever there is a significant impact on the bottom of the food chain, the entire food chain is seriously affected. Most of us are aware of drought impacts but may not be aware of the importance of the timing of seasonal events.


Phenology is the term used to describe the recording or study of first occurrence of biological events in their annual cycle: emergence of leaves, first flight of butterflies and first appearance of migratory birds.  In some respects phenological records have been a better indicator of weather and climate patterns than temperature records. After all, the modern thermometer was not invented until 1714 by Daniel Gabriel Fahrenheit. In Europe, viticulture records going back 500 years have given us detail on when grape leaves first appeared, when they set fruit, when fruit was harvested. Robert Marsham, the father of modern phenological recording, began recording the details of first flowering of hundreds of plants along with the emergence of insects in England. His family continued the record until 1958.


The United States Geological Service has a program called North American Bird Phenology Program. Millions of bird arrival- and departure dates were recorded for 870 species between 1880 and 1970.


In Japan and China the blossoming dates of cherry and peach trees have been recorded since the eighth century. 


And what does all this record keeping tell us? Jake Weltzin, executive director of the USA National Phenology Network and an ecologist with the USGS says, “There is a study coming out every week showing changes are occurring.” Lilacs in North America are leafing out and flowering earlier. Bee species in the Northeast are emerging earlier to match earlier flowering plants. Data collected on leafing dates of oak indicate that first emergence is eight days earlier now than 250 years ago; however, most of the changes have happened in the last 100 years. This corresponds to temperature records that show a 1.5-degree Celsius increase. And one more: Richard Fritter recorded the first flowering date for 557 British species for 40 years. His data indicates that 385 of these are flowering 4.5 days earlier in the last decade than in the previous four decades.


So what? If the flowers bloom earlier and the bees emerge earlier, what difference does it make? There are problems, mismatches. Some species react to day length rather than temperatures. This is especially true for bird migration and some insect breeding. When this mismatch occurs it leaves insects without food and plants without pollinators. The birds may fair better than the insect/pollen relationship.  Research in Maine shows only a modest relationship between climate change and spring arrival dates for 107 species of migratory birds. Perhaps migrants are more resilient to climate change. Other mismatches can occur. Consider the ptarmigan and the snowshoe hare, who change their appearance to better blend with a seasonal environment. Early snowmelt or late beginnings of winter can leave some of these critters conspicuous.


In the Arctic, where many birds migrate to breed and raise young, the problem might be dire. Ingrid Tulp and Hans Schekkerman of the Arctic Institute of North America are studying arthropods. What they have found is that peak abundance of arthropods was seven days earlier in 2003 than in 1973. If you are a hungry arctic bird trying to feed babies, missing peak abundance is the difference between a successful breeding season and a failed season. 


The Environmental Protection Agency has an extensive document titled “Climate Change Indicators in the United States.” They relate that the earlier arrival of spring may result in a number of changes: a longer growing season, more abundant invasive species and pests, and earlier and longer allergy seasons. Ouch!  More data will make for better understanding of the extent of climate change, the effects and what kinds of management plans can be designed to help species survive the changes. Humans have been paying close attention to the rhythms of nature for all of our history. It was a matter of our well-being, our very survival. It still is.



Katherine Eagleson is executive director of The Wildlife Center, located near Española, NM. The center works to protect NM’s wildlife and their habitats. 505.753.9505, www.thewildlifecenter.org




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