Jumping to conclusions in nature.

[Gloria]

Predicting natures response to climate change , don't rush. It's more complex than temperature .

https://www.sciencedaily.com/release...1128152722.htm

a new study of lowland and higher-mountain bird species by wildlife ecologists Bill DeLuca and David King at the University of Massachusetts Amherst now reports an unexpected and "unprecedented" inconsistency in such shifts. The majority of the mountain bird community responded against expectation and shifted downslope despite warming trends in the mountains. They say the result "highlights the need for caution when applying conventional expectations to species' responses to climate change."

Species shifts up and down mountainsides have been documented around the world but this is the first time that recent elevational shifts of birds have been found in the northeastern United States, they add. It should be noted that in this study, the lowland bird community shifted upslope over the 17-year study period, consistent with expectations given recent warming in the region.

The authors report that as predicted, the upper elevation boundary of nine out of 16 lowland species showed evidence of shifting upslope an average of 99 meters [about 325 feet] over the study period. But, they add, "contrary to our expectations, nine out of 11 mountain birds shifted their lower boundaries downslope an average of 19 meters [about 62 feet] over the 17-year study period."

A possible explanation for the observation might be changes in forest composition, DeLuca and King suggest. For example, red spruce and paper birch have declined (due in part to acid rain) in the ecotone, the transition between the lower elevation deciduous forest and the higher elevation coniferous forest, and "the void left by the decline of spruce and birch has, in part, been filled by balsam fir." Further, "all of the high-elevation species we found to be shifting downslope are closely associated with balsam fir," meaning these birds may be following suitable habitat.

Overall, 82 percent, or nine of the 11 high elevation species analyzed showed evidence of shifting downslope, while 10 of 16 or 63 percent of lowland species showed evidence of shifting upslope.

[havalotta]

Might be some downsloping going on in search of food as.....whatever moves up is certainly eating what the others had been depending upon~!

[dapjwy]

Originally Posted by havalotta

Might be some downsloping going on in search of food as.....whatever moves up is certainly eating what the others had been depending upon~!

Good point--I was thinking of competition becoming an issue, too.