It’s Hot! And Getting Hotter

The Impacts of Temperature Increase on CT's Ecology

Think it has been hot this month? You’re right. During July 2019, there have been 19 days with high temperatures of 90 degrees F or hotter, four heatwaves, and an average high temperature of just over 90 degrees F as measured at Bradley Airport. The annual average air temperature in Connecticut and the bottom and surface water temperature in Long Island Sound are increasing*. As a consequence of this temperature increase, warm-adapted songbirds and marine species are becoming more common.  While species diversity can be good, warm-adapted species, such as certain invasive species, can be detrimental to native species. 

Historic data indicate that the composition of Connecticut's songbird population is changing. Songbirds that prefer warmer climates are increasing at a faster rate than cold-adapted songbird species. The Council on Environmental Quality (CEQ) is adding this new indicator to its Annual Report, Environmental Quality in Connecticut, to highlight the impact of the state's warming climate on its animal inhabitants. 

For this new indicator, the CEQ examined the presence and abundance of a total of eighteen warm-climate adapted and cold-climate adapted songbird species since 1984 to assess the impact that climate change has had on certain songbirds. All eighteen songbird species were assessed using the CEQ’s species index derived from raw annual Northern American Breeding Bird Survey (BBS) data**. For the specific birds assessed, populations have increased. Warm-climate adapted songbirds have increased more than cold-adapted songbirds, which had a modest increase since 1984, but a decline in recent years.

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This trend toward warm-adapted species is also being mirrored for many of the finfish species collected in the Sound. The CEQ examined species diversity of Long Island Sound based on the mean number of cold-adapted species and warm-adapted species caught during DEEP’s Long Island Sound Trawl Surveys (spring and fall)***.

The trend for marine species indicates that since 1984, the mean number of warm-adapted species caught during the spring and fall trawl surveys increased while the average number of cold-adapted species declined since 1984. This trend is also consistent for the American lobster (not shown), which has seen a very significant decline, almost 90 percent, for the annual mean (spring and fall) trawl surveys since 1984. This decline is believed to be caused, in part, by changes in bottom water temperatures.

For more information on how a warming climate is affecting our environment go the Council’s Annual Report.

Sources:
* NOAA, National Weather Service Forecast Center: https://w2.weather.gov/climate/xmacis.php?wfo=box ;  University of Massachusetts: www.geo.umass.edu/climate/stateClimateReports/CT_ClimateReport_CSRC.pdf ; CT DEEP, Long Island Sound Water Quality Monitoring Program Group
** The Council developed an index from the raw BBS data: www.pwrc.usgs.gov/BBS. The methodology for the CEQ's index is described in its Annual Report. 
*** CT DEEP Long Island Sound Trawl Survey (LISTS), 1984-2018; no fall tow data for 2010. "Total" does not include subtropical fish. Mean Number of Species per Sample by Adaptation Group.