A Comparative Study of the Flora and Soils of Great Duck and Little Duck Islands, Maine, USA

Strong environmental gradients and varied land-use practices have generated a mosaic of habitats harboring distinct plant communities on islands on the coast of Maine. Botanical studies of Maine\u27s islands, however, are generally limited in number and scope. Baseline studies of Maine\u27s islands are necessary for assessing vegetation dynamics and changes in habitat conditions in relation to environmental impacts imposed by climate change, rising sea levels, invasive species, pests and pathogens, introduced herbivores, and human disturbance. We conducted a survey of the vascular plants and soils of forest, field, and ocean-side communities of Great Duck and Little Duck Islands, ME. These islands differ in environmental and land-use features, and in particular the presence of mammalian herbivores; Great Duck Island has had over a century of continuous mammalian herbivory while Little Duck Island has been largely free of mammalian herbivores over the last 100 years. We recorded 235 vascular plant species in 61 families on the Duck Islands, 106 of which were common to both islands. The composition, abundances, and diversity of plant species substantially differed within similar plant communities between the islands. These differences were particularly evident in the forest communities where Little Duck Island had significantly greater sapling regeneration and a more recent peak in tree recruitment. Soil properties also significantly differed between these islands, with a higher pH in all three communities and higher P, Ca, and K in field, forest, and ocean-side communities, respectively, on Little Duck Island, and higher soluble salts in forest and ocean-side communities of Great Duck Island. Together, our findings suggest that soil characteristics and the dominance and regeneration of vascular plant species can differ substantially even between adjacent islands with otherwise similar geologic characteristics and glacial history, and that mammalian herbivory along with other ecological factors may be important drivers of these differences

Biological Inventories of Schoodic and Corea Peninsulas, Coastal Maine, 1996

This project was designed to complete a preliminary biological inventory of US Navy and Acadia National Park lands on Schoodic and Corea Peninsulas in coastal Maine, with the overall goal of providing the Navy and the National Park Service with natural resource information sufficient for management decisions. In this region, lands administered by these agencies are adjacent to each other and present a unique opportunity to cooperatively assess and manage natural resources. Prior to 1994, basic biological information on the Schoodic Peninsula region was scarce. A preliminary biological inventory was undertaken in 1994, which surveyed amphibians and reptiles, terrestrial mammals, and vascular plants (Mittelhauser, et al. 1995). The present project involved intensive studies of three taxonomic groups not studied in the 1994 survey (bats, landbirds, and bryophyte plants) and follow-up studies of amphibians, terrestrial mammals, and vascular plants. Specific objectives were to: (1) compile species lists for taxa not previously studied; (2) update species and habitat information of taxa studied in 1994; (3) identify federal and state-listed endangered or threatened species and other species of local or state-level management concern; and (4) organize available data for further resource management decisions. The study area included all US Navy lands on Corea Heath and Big Moose Island (approximately 250 hectares) and all Acadia National Park lands on Schoodic Peninsula and Big Moose Island (approximately 800 ha). Corea Heath is designated as a Maine Critical Area, and recognized as a one of the largest and most southerly coastal raised peatlands in North America. The jack pine (Pinus banksiana) stands on Schoodic Peninsula, Big Moose Island, and Corea Heath also are designated Maine Critical Areas. Hence the region is of considerable interest in terms of the biology and conservation of its ecological communities

A complex speciation-richness relationship in a simple neutral model

Speciation is the "elephant in the room" of community ecology. As the ultimate source of biodiversity, its integration in ecology's theoretical corpus is necessary to understand community assembly. Yet, speciation is often completely ignored or stripped of its spatial dimension. Recent approaches based on network theory have allowed ecologists to effectively model complex landscapes. In this study, we use this framework to model allopatric and parapatric speciation in networks of communities and focus on the relationship between speciation, richness, and the spatial structure of communities. We find a strong opposition between speciation and local richness, with speciation being more common in isolated communities and local richness being higher in more connected communities. Unlike previous models, we also find a transition to a positive relationship between speciation and local richness when dispersal is low and the number of communities is small. Also, we use several measures of centrality to characterize the effect of network structure on diversity. The degree, the simplest measure of centrality, is found to be the best predictor of local richness and speciation, although it loses some of its predictive power as connectivity grows. Our framework shows how a simple neutral model can be combined with network theory to reveal complex relationships between speciation, richness, and the spatial organization of populations.Comment: 9 pages, 5 figures, 1 table, 50 reference

The Alpine Vascular Plants of Baxter State Park, Maine, USA

We conducted 12 days of field surveys on five mountains over 1100 m in elevation (Katahdin, North Brother, South Brother, Mount Coe, and The Owl) in Baxter State Park (BSP), Maine during the summers of 2013–14. In addition, we examined historic manuscripts, unpublished data, and herbarium records for plant records from the five mountains. Katahdin, the largest and tallest of the five mountains, has a rich history of botanical exploration and we documented 1559 herbarium vouchers that were collected from the mountain, primarily before the mid-1900s. Combining all data sources, we documented 38 families, 87 genera, and 131 taxa of vascular plants growing on our five study mountains above 1100 m in elevation from the 1800s to the present. This includes 28 taxa historically documented in the study area but not observed since 1980 at over 1100 m. In our study area, we found 16 taxa listed as endangered in Maine, 16 taxa listed as threatened, 10 taxa listed as of special concern, and five taxa considered possibly extirpated. This work provides a reference for future monitoring and plant conservation efforts within BSP and alpine habitats in Maine

Island species lists and island properties

First sheet is an island-species matrix of species presences (0 or 1). Second sheet includes spatial data for each island. Taxonomic nomenclature follows Haines (2011). See associated publication for details on data collection methods and supplemental appendix for additional metadata