John Bognar

Temporal and spatial changes in an area of the New Jersey Pine Barrens landscape

In order to document the extent of landscape fragmentation for a section of the New Jersey Pine Barrens region, we have used satellite image and spatial analysis to monitor landscape change between 1972 and 1988. Land-cover patterns were quantified by mean, number, and size of patches; and amount of edges between land cover types. During the intervening sixteen year period, fractal dimension, diversity, and contagion generally decreased while dominance, disturbance and edges increased, indicating a trend to a more dissected and disturbed landscape. There was an increase in the number of forest patches and a significant decrease in the average size of forest patches. In contrast, the mean patch size for the non-forest category has increased as a result of a coalescence of patches. The landscape fragmentation is shown by a downward shift in the distribution of forest patches by size class. These changes in landscape pattern have implications for many ecological processes and resources. Management practices need to consider landscape fragmentation in the Pinelands National Reserve in order to preserve the essential character of the Pine Barrens landscape.

Use of GIS mapping and modeling approaches to examine the spatial distribution of seagrasses in Barnegat Bay, New Jersey

Due to the ecological importance of seagrasses and recent indications of disease and dieback, we have synthesized existing mapped survey information concerning the spatial and temporal distribution of seagrass beds (primarily eelgrass,Zostera marina) in Barnegat Bay, New Jersey. Mapped surveys from the 1960s, 1970s, 1980s, and 1990s were digitized and compiled in a geographic information system to facilitate analysis. Comparison of the earlier maps with the 1990s survey shows an overall decrease of approximately 2,000 to 3,000 ha in the area of seagrass beds. While there are indications of seagrass decline, due to the great difference in mapping methods used for each of the surveys, we are cautious in directly attributing the decrease in mapped eelgrass acreage to a large-scale dieback. We examined the extent to which light could be used to predict the distribution of seagrass in Barnegat Bay. Data on Secchi depth throughout the bay were combined with a modification of an existing model (Duarte 1991) of the relationship betweenZ. marina compensation depths and light attenuation coefficients to predict the distribution of seagrasses in Barnegat Bay. When compared with mapped seagrass distribution in the bay, the model correctly predicts seagrass presence-absence over two-thirds of the time. The majority of the model error is due to errors of commission, i.e., the model predicts seagrass occurrence where it was not observed to occur. Most of this commission error is located in specific geographic areas (i.e., southern third of Little Egg Harbor and the western shoreline of the bay).

Spatial variability of digital soil maps and its impact on regional ecosystem modeling

This paper discusses some of the practical difficulties encountered in using generalized regional soils maps such as the U.S. Soil Conservation Service State Soil Geographic Data Base (STATSGO) for landscape to regional level ecosystem modeling. For highlighting regional trends, the STATSGO-derived maps are adequate. However, caution is warranted when using the same maps for modeling at a landscape level due to the generalized nature of the STATSGO data coupled with the inherent spatial variability of soils. The variability of soil water holding capacity (SWHC), within a STATSGO class was quite large with a median coefficient of variation of between 40 and 60%. Comparison of SWHC values derived from finer scale county level soil surveys with STATSGO data showed large discrepancies. Simulated outputs from the forest ecosystem model, PnET, differed by approximately 20% depending on the source of SWHC input data. To improve the utility of regional soils databases for modeling purposes, estimates of the spatial variability of soil properties need to be better quantified and communicated to the prospective data user.

The Application of WebGIS Tools for Visualizing Coastal Flooding Vulnerability and Planning for Resiliency: The New Jersey Experience

While sea level rise is a world-wide phenomenon, mitigating its impacts is a local decision-making challenge that is going to require site-specific remedies. Faced with a variety of conflicting mandates and uncertainty as to appropriate responses, local land use planners and managers need place-based decision support tools. With the increasing availability of high-resolution digital elevation models and the advancing speed and sophistication of web-based mapping, a number of web geographic information systems (GIS) tools have been developed to map and visualize what areas of a coastal landscape will potentially be flooded under different scenarios of sea level rise. This paper presents a case study of one such WebGIS application, NJFloodMapper (www.NJFloodMapper.org), with a focus on the user-centered design process employed to help our target audience of coastal decision-makers in the state of New Jersey, USA, access and understand relevant geographic information concerning sea level rise and exposure to coastal inundation, as well as assess the vulnerability of key infrastructure, populations and natural resources within their communities. We discuss the success of this approach amidst the broader context of the application of WebGIS tools in this arena. Due to its flexible design and user-friendly interface, NJFloodMapper has been widely adopted by government and non-governmental agencies in the state to assess coastal flooding exposure and vulnerability in the aftermath of a recent destructive coastal storm. However, additional

Size-class structure and hardwood recruitment in Atlantic white cedar swamps of the New Jersey pinelands1

ZAMPELLA, R. A., K. J. LAIDIG (Pinelands Commission, P.O. Box 7, New Lisbon, NJ 08064), R. G. LATHROP, AND J. A. BOGNAR (Center for Remote Sensing and Spatial Analysis, Cook College, Rutgers University, 14 College Farm Road, New Brunswick, NJ 08901). Size-class structure and hardwood recruitment in Atlantic white cedar swamps of the New Jersey Pinelands, J. Torrey Bot. Soc. 126:268-275. 1999.-We analyzed the size-class structure of Atlantic white cedar (Chamaecyparis thyoides) swamps established prior to 1930 to determine if there is any evidence that cedar-swamp succession is controlled through replacement by hardwood species such as red maple. The size-class distribution patterns that we observed for cedar in most stands were characteristic of even-aged stands undergoing density-dependent mortality or self-thinning. Hardwoods, including red maple, blackgum, sweetbay, and grey birch, contributed little to total basal area and occurred at low densities. Red maple was the most common hardwood. For this species, large-diameter (?10 cm) stems, relative density of small (<10 cm) and large (?10 cm) diameter stems, expressed as a percentage of total small-diameter and large-diameter cedar and maple stems, relative basal area, and canopy cover increased in relation to increasing cedar-stem size and decreasing cedar-stem density. Although these trends suggest that red maple abundance and recruitment may be related to cedar size-class structure, there was no significant difference in the absolute density of < 5 cm diameter maple and cedar stems, and the absolute density of 5-9.9 cm diameter cedar was greater than that of red maple. It is questionable whether red maple or any hardwood species occurred at densities sufficient to allow them to respond quickly to canopy gaps created by the death of overstory trees in the swamps that we studied. Our study indicates that hardwood replacement of cedar in swamps is not a certain outcome of cedar-swamp succession. If Atlantic white cedar is actually replaced by hardwoods as individual trees age and die, the replacement process may take centuries. Even then it may only result in conversion to mixed stands dominated by cedar rather than the complete loss of cedar.

Landscape Scale Modeling of the Potential Effect of Groundwater-level Declines on Forested Wetlands in the New Jersey Pinelands

The objective of the study, which is a component of a comprehensive evaluation of the hydrologic and ecological effects of groundwater pumping from the Kirkwood-Cohansey aquifer, was to apply empirically determined hydrology-vegetation models to develop geographic information system (GIS)-based landscape models for three study basins in the New Jersey Pinelands. The wetland- indicator modeling suggests that the area dominated by wetland species will decline in area with increased groundwater withdrawal due to the predicted drop in water table. While some patterns revealed in the results are reasonably consistent across basins, other changes are a function of the unique topographic form and hydrologic characteristics of a particular basin. The results suggest that cedar and hardwood swamps which are at the wetter end of the water table gradient will show the greatest percent declines in area. The landscape modeling suggests that at the higher levels of groundwater withdrawal the decline of wetland area will be especially severe in the upper headwaters of the basins, and that there will be ‘retreat’ of existing wetlands to a narrower streamside corridor. The landscape modeling also suggests that there will be a change in the broader landscape pattern with a simplification of the wetland mosaic with fewer patches.

Establishment of Marine Protected Areas to Reduce Watercraft Impacts in Barnegat Bay, New Jersey

ABSTRACT Lathrop, R.G.; Bognar, J.; Buenaventura, E.; Ciappi, M.; Green, E., and Belton, T.J., 2017. Establishment of marine protected areas to reduce watercraft impacts in Barnegat Bay, New Jersey. In: Buchanan, G.A.; Belton, T.J., and Paudel, B. (eds.), A Comprehensive Assessment of Barnegat Bay–Little Egg Harbor, New Jersey. To help address the adverse effects associated with motorized boating activities in the Barnegat Bay National Estuary, New Jersey, a network of marine protected areas was identified to receive special consideration and management. Officially designated in spring 2012, the boundaries for these ecologically sensitive areas (ESAs) were based on best professional judgment and a geographic information system–based assessment using extant maps of habitat natural features, including shellfish beds, submerged aquatic vegetation (SAV), presence of endangered species, and proximity to bird nesting areas. The need for and the subsequent effectiveness of ESA designation in managing the adverse effects of recreational boating activities were evaluated. Two indicators of boating usage and impact were mapped using visual interpretation of high-spatial-resolution aerial photography: (1) concentrations of boating activity (either moored or in transit) and (2) damage caused by both propeller-driven and personal watercraft–type boats to SAV habitats. The mapping clearly shows extensive prop scarring, with hot spots of damage in specific ESAs, confirming that some form of spatial zoning, with slow speed regulations or outright closures, are warranted to protect SAV. The mapping documents significant levels of boating usage and boat scarring still occurring within the ESAs postdesignation. Additional management actions to reduce boating impacts are clearly warranted. To reach a spectrum of the recreational boating community, a three-pronged approach that includes public education in responsible boating practices, placement of appropriate signage at the ESA boundaries, and routine enforcement by state marine police and conservation officers is recommended.

The Role of Mid-Atlantic Ocean Data Portal in Supporting Ocean Planning

The Mid-Atlantic Regional Council on the Ocean (MARCO) was established in 2009 to enhance the vitality of the regions ocean ecosystem and economy. One of MARCO’s first action items was the development of the Mid-Atlantic Ocean Data Portal to serve as an on-line platform to engage stakeholders across the region with the objective of improving their understanding of how ocean resources and places are being used, managed, and conserved. A key component is the Marine Planner, an interactive map-based visualization and decision support tool. These types of on-line tools are becoming increasingly popular means of putting essential data and state-of-the-art visualization technology into the hands of the agencies, industry, community leaders, and stakeholders engaged in ocean planning. However to be effective, the underlying geospatial data has to be seen as objective, comprehensive, up-to-date and regionally consistent. To meet this challenge, the portal utilizes a distributed network of web map services from credible and authoritative sources. Website analytics and feedback received during the review and comment period of the 2016 release of the Mid-Atlantic Ocean Action Plan confirm that the Data Portal is viewed as integral to this ocean planning process by the MidAtlantic Regional Planning Body and key stakeholders. While not all stakeholders may agree with specific planning decisions, there is broad based agreement on the need for better data and making access to that data widely available.