What is 'Diversity'? Simply all variation at all levels of organization, from the genes within a single local population, to the species composing all or part of a local community, and finally to the communities themselves that compose the living parts of the diverse ecosystems of the world. --E.O. Wilson

Native flora is an important component of biological diversity in the state of New Jersey. However, fifteen percent of New Jersey’s native flora is classified as endangered, and biological diversity is continually diminished as species are lost from the state. The purpose of this study was to uncover spatial patterns and data trends in endangered plant population extirpations, threats, and fluctuations in New Jersey. This project allows a future phase that develops environmental indicators for the assessment of endangered plant species population health and threats.

Populations of 331 endangered and 32 extirpated (or locally extinct) vascular plant species in New Jersey were examined using the Natural Heritage Biological and Conservation Database (BCD). Plant population occurrence data was verified and updated and was then entered into a GIS for spatial analyses. Data describing threats to extant (i.e. currently existing) plant populations and causes of population extirpation (i.e. extermination) were examined, and landscape trends were determined by grouping populations according to species, habitat types and at three different geographic scales – county, watershed and statewide.

The analyses and maps of extant and extirpated population distributions helped to identify:
• the most severe threats to endangered plants in New Jersey (which include development and habitat degradation)
• the habitat types that are most likely to include endangered plant species (palustrine) and
• geographic areas that need the most attention in terms of endangered plant conservation

It is hoped that this study will help in the development of appropriate policy to stem future losses of native flora in New Jersey.