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Thursday, December 22, 2011

FOREST BIRD STUDY INVESTIGATES THE ROLE OF ENERGY IN CONTROLLING DIVERSITY


A weak but negative relationship exists between primary forest productivity and the number of bird species that inhabit forests.


A stronger, positive winter relationship exists between temperature (greater elevation and latitude equals lower average temperature) and the number of species that inhabit forests.

The U. S. Geological Survey is collaborating with Bird Conservation Research, Inc. as we continue to analyze the year-round distributions of southern New England’s forest birds. USGS is providing technical assistance in the field of satellite imagery.

We have already demonstrated that a significant winter relationship exists between forest bird diversity and winter energy availability (see above) in that our region’s birds move to warmer, coastal forests in winter. This is likely because birds can live near the coast for fewer calories/day. In winter, when food is limited, reducing energy costs translates into a greater probability of survival. Other of our analyses demonstrate that particularly our wintering permanent resident species congregate toward the coast.

Despite such a relationship, summer average temperatures (as measured by elevation and latitude) exhibits little relation to where birds are found. This is likely because during summer, energy in the form of forest productivity becomes available. This productivity is ultimately what produces the insects, fruits and seeds that birds rely on for food.  

Measuring the productivity of forests is possible with satellite imagery. Satellites routinely make a measurement called the normalized difference vegetative index, or NDVI, which is a measure of the relative greenness of forests. Research has shown that forest greenness serves as a measure of primary productivity.  NDVI data are gathered by the U. S. Geological Survey, so we have teamed with them to seek relationships between their data and our large scale surveys of bird distributions. 

To date, our findings have not been consistent with expected trends.  As noted, theory predicts that NDVI should relate positively to the number of bird species. Instead, our data show a weak negative relationship between NDVI and species (see above). The reason for this pattern is the subject of ongoing investigations.

 

Saturday, December 17, 2011

VIDEO FOCUSES ON CONNECTICUT RIVER FLOODPLAIN


Pratt Cove in Deep River, Connecticut is a tidal backwater of the lower Connecticut River.

The first video produced by Bird Conservation Research, Inc. was Floodplains.  It is the pilot video in a series designed to enhance the AP Environmental Science curriculum.  The video series grew out of our realization that available video resources were generally overly simplistic in content and, hence, not suited to the college-level rigor required of AP courses.  Furthermore, we found that there was precious little available that dealt specifically with New England habitats. 

The Connecticut River is one of the great and largely intact river ecosystems of the Northeast.  We characterize the floodplain communities of this river and investigate the development of the system over time, how the physical environment shapes the biological environment, and the principal flora and fauna present in the floodplain ecosystem.

Friday, December 9, 2011

VIDEO ON NEW ENGLAND BOGS AVAILABLE

The native Rhododendron, primarily a tree of the coastal plain and of the southern Appalachian mountains, straggles north into New England, particularly in the bogs of southern Rhode Island, southern Massachusetts and southeastern Connecticut.

To date, Bird Conservation Research, Inc. has produced videos on the floodplain of the Connecticut River and on the barrier beach of Napatree Point, Rhode Island.  Our latest effort highlights the bog habitat, and this is now available for free download from our web siteThese videos are designed to suppliment the AP Environmental Science curriculum.

The video Bogs describes two of the principal bog environments found in southern New England: northern-and southern associated bogs. It describes the bog formation process by examining the development of old black spruce bogs on the Berkshire plateau of western Connecticut.  It then shifts to a young Atlantic white cedar bog in northeastern Connecticut and explores the actively growing edge of a new bog mat. It concludes by examining an old cedar bog present along the southern Connecticut-Rhode Island border, which contains plant species that colonized the area not long after glacial times.