Studies of changes in plant species composition have been underway since 1978 on three islands in Lake Winnipesaukee, New Hampshire. Data were summarized from the understory herbaceous and woody vascular plant species, along with woody overstory species, found in long-term monitoring plots on three islands owned and/or managed by the Appalachian Mountain Club in Lake Winnipesaukee. The three islands named Three Mile, Hawk's Nest, and Blueberry Island, were sampled in the central portion of New Hampshire in 1978, again in 1991, and most recently in 2001. The total numbers of overstory and understory species for each of four land use zones were modeled by bootstrapping data for each sampling period.
Results/Conclusions
Two of the most important woody understory species consistently throughout the sampling years were: Acer rubrum and Tsuga canadensis on Hawk's Nest; Acer rubrum and Vaccinium corymbosum on Blueberry Island; Acer rubrum and Tsuga canadensis on Three Mile Island. Total number of overstory species for all land use zones except the Urban zone increased in the period between 1978 and 1991, and numbers were static for the period 1991 to 2001. The total number of understory species increased in all land use zones between 1978 and 1991, and increased only in the urban zone between 1991 and 2001. This increase in species richness may be attributed to a combination of natural succession and the implementation of a land-use management plan on all three islands.
