Research and Monitoring

Our science research influences our stewardship work. Over the last 10 years, Teatown staff members have studied many aspects of the biodiversity and health of the habitats on our preserve to determine what management is needed to promote the health of the region. The monitoring we do often depends on the prior experience of our scientists and the observations we make on the preserve. If there are any gaps in the monitoring we are able to do, we often collaborate with outside professionals when resources allow. Here is a list of some of our current and past monitoring projects.

Long Term or Annual Projects

Forest Health Monitoring

We study many aspects of the forest vegetation and wildlife to determine overall health. Our longterm forest plots can measure canopy dieback, tree density and coverage, seedling abundance or regeneration potential, and wildflower or other plant diversity. We can determine what impact deer are having on the forest, threats from invasive plants or insects, and can also determine if our management activities are effectively restoring the health of our forest.

We have deer exclosures to directly monitor the impact of deer as well. These exclosures were installed in 2013.

In 2017 we installed several plots to monitor the growth of American beech root suckers and witch hazel stump spouts. Measuring the height of the growth of the plants can help us determine how much the deer are impacting the vegetation on the preserve. American beech is not a preferred food for deer, while witch hazel is. Impacts to both species of plants are high which indicates that deer are overabundant and feeding on a species they don’t typically prefer. By annually monitoring how tall the root suckers and sprouts are, we can also determine if our deer management program is successfully helping us to restore the health of the forest.

Through our longterm forest plots and just walking along trails, we can also monitor for invasive insect pests such as the emerald ash borer. We also monitor invasive plant presence along trails, roads and other disturbed areas to determine where management is most needed and to remove newly invaded plant species.

Deer Population Monitoring

We have several different methods of monitoring the deer population on the preserve. We use camera traps to identify individual bucks on the preserve. Each antlered male deer has unique antler shape, size and number of points that can be used to identify males individually. Over the course of September, we set up numerous cameras on deer trails to identify males, and count the frequency that they, does and fawns walk in front of cameras. From here, we use a formula designed by scientists to extrapolate our deer population.

We also conduct pellet counts in the late winter to estimate the deer population. We walk five one mile long transects and stop at certain intervals to determine if and count how many deer pellet groupings are within a certain distance of where we stop. From here we insert our numbers into a formula that can tell us what our deer density is at Teatown.

Every few years we hire a company to fly over the preserve and count the number of deer as a snapshot-in-time. They use forward-looking infrared radar (FLIR) to count deer at night when there are no leaves on the trees.

We apply these three different techniques because estimating a deer population is inherently difficult. We can use the information to serve as index from year to year to determine if our population is stable, decreasing or increasing and adjust our deer management program as appropriate. In general, the vegetation is what tells the bigger story about our deer population which is why we also have numerous plots throughout the forest.

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Beaver Management

We don’t have any formal beaver monitoring programs. We regular monitor our spillways, trees being removed by beaver, or damage to WFI to mitigate their impacts. We also set up cameras to watch their activity in these areas as well.

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Our Lakes

Teatown, Vernay and Shadow Lake are all manmade lakes that are eutrophic. A eutrophic lake is one with a high amount of nutrients that allows for abundant growth of plants and algae, which can deplete the dissolved oxygen content in the water. Eutrophication can occur through natural processes, but is often mostly associated with runoff from agricultural land or surrounding developments. Teatown monitors the water quality in Teatown and Vernay Lakes during the growing season to observe any unusual changes. We also monitor the vegetation in our lakes, and particularly look for invasive species. We have a few invasive aquatic plants in our lakes, but most are currently at low densities. We regularly monitor and manage the water chestnut on Teatown Lake so that it does not spread any further or its seeds hitch a ride on a bird or mammal moving through the area. We also regularly monitoring for hydrilla, a highly invasive plant recently found and now being treated in the Croton River.

We have had some recent assessments done in Teatown Lake to determine how to better manage the lake in the future.

Carnivore Monitoring

Teatown monitors carnivore presence on the preserve using camera traps. Camera traps offer resource managers and researchers a unique way to non-invasively study wildlife on the preserve. Using the information we collect, we can monitor when new carnivore species appear and work to determine what conservation actions are needed to protect what we have present here. In addition to confirmed sightings from staff and visitors, our cameras have also detected activity of coyote, red fox and bobcat on the preserve. In the winter, we often see fisher on the cameras, and in the spring we occasionally see black bears moving through Teatown. Part of our carnivore monitoring is done in collaboration with EMMA.

After detecting fisher at Teatown for the first time in 2014, this piqued our interest into launching a more elaborate study throughout Westchester in 2015 and 2016. With the help of Westchester County Parks and many other scientists and volunteers in the region, we studied fisher presence at over 80 different locations over two years. This study revealed that fisher were present at 6 different locations, which means they are likely more spread out than at just those sites. We continue to work to modify our methods of study to determine where fisher reside across the Westchester region.

Phenology Trail

Through EMMA, we monitor plant phenology along a designated trail. Phenology is the study of when life cycle changes occur in plants or animals. For example, when do flowers bloom? When do frogs lay eggs? When do leaves turn colors in the fall? These questions and many more are important for understanding our local and regional climate and how life cycles of plants or animals are changing over time. Currently we are only recording plant phenology, but may include animal phenology in the future.

Other projects

Breeding and Wintering Bird Monitoring

Birds are charismatic wildlife that we hear and see all the time in nature. Often times, other than perhaps squirrels or mosquitos, they may be the only wildlife we notice in the forest. In the early summer, scientists record breeding bird data at designated points to determine bird diversity and population size on the preserve. Currently, the tufted titmouse is the most common breeding bird at Teatown. Each year we can determine if any major changes are occurring in our bird populations, or better yet over many years, we can see a pattern in these changes if they occur. Teatown also participates in Audubon’s Peekskill Christmas Bird Count. Volunteers walk and drive all around Teatown to count and identify birds. This information is also useful for monitoring trends in bird populations.

Woodland Pools

Woodland or vernal pools are seasonal pools in the forest that provide unique breeding habitat for frogs, salamanders and other species. We count and identify egg masses to determine what species are breeding in our pools and how successful they are in surviving through the growing season.