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Natural Resource Inventories

How well do our preserves provide habitat for plants and animals in need of conservation? Do we have the best information to make strategic decisions in applying the best practices for managing our wildlife habitat? What number of plant and animal species does our land support?

The answers to all of these questions are fundamental to correct land management. To answer them, WVWA embarked on a series of field investigations under our Suburban Wilderness Initiative.

During 2013, Doctors Ann Rhoads and Timothy Block of the Morris Arboretum completed a Natural Resources Inventory to document the diversity of plant species on our lands. In 2014, Blaine Rothauser of BR Environmental completed an Entomological Inventory of the WVWA Preserves and Scott Angus of RBA Group completed a Herpetological Study. The following year, 2015, Alicia Shenko of Delaware Valley University completed a Mammal Survey.  

The final reports are very telling about the state of biodiversity in our preserves, and allowed us to identify which species are in need of conservation and for which management should be focused. For the most part, the WVWA preserves and the Green Ribbon Trail are a combination of forest fragments of various sizes; habitat islands surrounded by a sea of development. Forest edge prevails everywhere; areas that differ from true forest interior where wind, less moisture and direct sun creates a fierce competition among native plants and exotic ones. 

It comes as no surprise that our preserves are challenged. Deer overabundance and invasive plants have radically altered the landscape.  Their constant impact have reduced the number of native species to 65% of plant species found throughout our preserves.  The structure of the forest has been greatly impacted - healthy layers of grasses and wildflowers, emerging saplings and understory trees and shrubs that should naturally occur, have been sabotaged by too many over-browsing deer. The lack of cover decreases the habitat available for wild animals and birds which depend upon it for food, cover and breeding sites. Everything from ground nesting Ovenbirds to timid shrews eventually disappear when the habitat cannot sustain them.

While these conditions come as no surprise, there are some very encouraging trends. Rhoads and Block have acknowledged the value of the WVWA’s successful effort to preserve the riparian corridors of the Wissahickon Creek and its tributaries. Rothauser describes the corridors as the future key to sustaining a healthy population of species.  A total of 574 plant species, 955 insects and 20 amphibians and reptiles were identified in the studies. The relatively unspoiled Crossways Preserve has the highest concentration of native plants at 70% and many of our preserves are home to state-listed species, including the Juniper Hairstreak and the Eastern Box Turtle. Without refugia habitat like the WVWA preserves, many of these species would not persist within residential or commercial developments, as described by Shenko.  All species listed in local, state, or national management plans as those needing conservation and protection will be the focus of WVWA’s Conservation Resources Program.

A Species of Concern is a classification that recognizes the long term decline of a species in our region that if left unprotected, is likely to become extinct.  From the baseline reports and the expert scientists’ recommendations, WVWA will develop Wildlife Habitat Plans for each Preserve that will protect and promote these species and in doing so, support overall biodiversity.‚Äč

To get more information about the Natural Resource Inventories contact WVWA at 215-646-8866 or info@wvwa.org.




Mammal Study


MAPS Summary Report


Natural Resources Inventory


Entomological Inventory


Comprehensive Herptile Survey


Note: Inventory files are large documents and not recommended for mobile devices