Introduction:

\ What are vernal pools?

Vernal pools are confined depressions, either natural or man-made, that maintain ponded water for part of the year and are devoid of breeding fish populations. These temporary wetlands provide habitat to many species of amphibians-several of which breed exclusively in vernal pools-as well as a multitude of insects, reptiles, plants, and other wildlife.

\ Why do they need protection?

Although the NJ Freshwater Wetlands Protection Act has been in place since 1989, it has done little to protect vernal pools because wetlands <1 acre (most vernal pools in NJ are <0.25 acre) were exempt from the regulatory protection. Vernal pools could be filled, drained, or modified with a general permit. The loss of this critical habitat put the species that depend on vernal pools for breeding habitat at risk. Click here and rollover the image to view an example of vernal pool habitat loss.

\ Who is involved in this project?

In conjunction with new, long-awaited Department of Environmental Protection legislation adopted in September 2001 that affords vernal pools protection, the Endangered and Nongame Species Program's established its Vernal Pool Project, which is dedicated effort mapping and surveying vernal pools throughout the state. Vernal pools that provide documented habitat for certain amphibian and reptiles species (= certified) will be afforded regulatory protection through the new rule. Eventually these certified vernal pools will also be integrated as a data layer into the Landscape Project's Critical Habitat Mapping, which is a comprehensive map of New Jersey's wildlife habitat intended to assist land use planning.

Because of their ephemeral nature and small size, locating vernal pools with conventional mapping is a challenging task. Therefore,The Rutgers University Center for Remote Sensing & Spatial Analysis (CRSSA) has been contracted to develop a suite of computer-aided techniques to identify and delineate vernal ponds in New Jersey using an assortment of on-screen digitizing, image processing and GIS-based classification techniques.

Methods:

The first step of the vernal pool mapping process will involve developing a model that highlights areas of likely vernal pool occurrence. The second step will involve either image interpretation and/or field work to verify actual vernal pool occurrence. A hierarchical decision-making model using existing GIS coverages will be developed to map showing probability or likelihood of vernal pool occurrence. This model will use a variety of GIS inputs: freshwater wetlands, soil type, land use-land cover, digital elevation models and 1995/1997 color infrared digital orthophotography (DOQ). With the probability coverage as a mask, vernal pools will be identified via on-screen digitizing of the CIR DOQ's. The efficacy of seed pixel digitizing approach in delineating vernal pools boundaries will be examined. CRSSA will integrate mapped vernal pool data from a variety of sources, including the ENSP, New Jersey Geological Survey, Natural Heritage Program, into the final coverage. Due to the limited budget and time period for this study, the Highlands, Pinelands and Delaware Bayshore landscape regions will be the focus of our effort. An independent accuracy assessment will be performed to quantify the resulting GIS coverage's accuracy in mapping the locations of vernal pools.

Purpose of this site:

Provide web-based graphics, including interactive maps, to display the results of the mapping process.