University of New Hampshire
Plant Biology & Horticulture
Mentor: Thomas Lee, Associate Professor of Plant Biology
The Diversity and Persistence of Understory Plant Species in the College Woods Natural Area, Durham, New Hampshire
Biodiversity, the variability of all living things, is threatened on a global scale. It is estimated that 15 - 20% of all species on earth could become extinct by the year 2000. Ecological reserves are critical to the persistence of biological diversity. Most reserves are islands of natural habitat surrounded by developed areas. Some extinction on islands is expected due to lack of immigration and genetic diversity. Rare species are most likely to go extinct. Ecologists use minimum viable population to ensure the persistence and genetic variability of species.
Objectives of this study were to assess the diversity, abundance and distribution of understory plant species and persistence of rare species present in the College Woods Natural Area. Communities were systematically sampled throughout June-July, 1999. Plants were identified, dried and preserved on herbarium sheets. Preliminary results showed that eighty-six understory plant species from 31 families were present in the study area. Thirty species were restricted to one community, 23 species were observed with less than three populations and 25 species were observed with less than 50 individuals in each population. Species found in only one or two communities, with less than 50 individuals should be less likely to persist. Species that had less than three populations and fewer than 50 individuals per population were most vulnerable to extinction, comprising roughly 26 % of the flora of College Woods. The persistence of the species found in only one habitat is less likely if the area is not buffered by more natural habitat. The red maple swamp community is surrounded by other parts of the reserve; therefore species found there are more likely to persist. Species found on the northern edge of the reserve, where there is a wetland associated with the Hemlock-Beech community, are the least likely to persist due to proximity of human activity.