Life Sciences Commons^™

Repeat Disturbances Have Cumulative Impacts On Stream Communities, Jessica M. Haghkerdar, Jack R. Mclachlan, Alexis Ireland, Hamish S. Greig

Biology and Ecology Faculty Scholarship

1. Climate change has altered disturbance regimes in many ecosystems, and predictions show that these trends are likely to continue. The frequency of disturbance events plays a particularly important role in communities by selecting for disturbance -tolerant taxa.

2. However, ecologists have yet to disentangle the influence of disturbance frequency per se and time since last disturbance, because more frequently disturbed systems have also usually been disturbed more recently. Our understanding of the effects of repeated disturbances is therefore confounded by differences in successional processes.

3. We used in -situ stream mesocosms to isolate and examine the effect of disturbance …

Strong Zonation Of Benthic Communities Across A Tidal Freshwater Height Gradient, Jack R. Mclachlan, Jessica M. Haghkerdar, Hamish S. Greig

Biology and Ecology Faculty Scholarship

Trade-offs associated with environmental gradients generate patterns of diversity and govern community organisation in a landscape. In freshwaters, benthic community structure is driven by trade-offs along generally orthogonal gradients of habitat permanence and predation—where ephemeral systems are physiologically harsh because of drying stress, but inhabitants are less likely to be under the intense predation pressure of more permanent waterbodies. However, in tidal freshwaters, these two stressors are compounding, and the trade-offs associated with them are decoupled.
2. We investigated benthic community structure in a tidal freshwater habitat. These communities experience a suite of conditions atypical for a freshwater habitat: twice-daily …

Dorothy J. Jackson Fres Fls, Scottish Entomologist: A Bibliography, Jack R. Mclachlan

Biology and Ecology Faculty Scholarship

Dorothy Jean Jackson FRES FLS (1892-1973) should be familiar to anyone interested in water beetles. She published prolifically on the ecology, distribution, flight capacity, and parasites of water beetles, and made especially important contributions to our knowledge of dytiscids. Here I provide a more extensive bibliography of her work that is almost certainly incomplete, but I think includes most of her scientific output between 1907 and 1973. Her first paper was published when she was 14 years old, and her last was completed by Jack Balfour-Browne and published posthumously.

Bees Of Maine, With A State Species Checklist, Alison C. Dibble, Francis A. Drummond, Constance Stubbs, Michael Veit, John S. Ascher

Biology and Ecology Faculty Scholarship

We present a new county checklist developed from bee research in Maine since the 1800s. The list contains 278 bee species in 37 genera and 6 families, of which all but 8 are native, with ≥50 taxa each in Andrena and Lasioglossum. Data for 16 counties from publications, museum collections, and recent surveys varied in number of species from 8 (Androscoggin) to 197 (Hancock). Research since 1930 on Vaccinium angustifolium (Lowbush Blueberry) led to many records. Twenty-one species are considered unusual, including 3 first recorded in 2016: Epeoloides pilosulus, Melitta melittoides, and Holcopasites calliopsidis. Maine records …

Habitat Occupancy Of Rusty Blackbirds (Euphagus Carolinus) Breeding In Northern New England, Usa, Luke L. Powell, Thomas P. Hodgman, Ian J. Fiske, William E. Glanz

Biology and Ecology Faculty Scholarship

The Rusty Blackbird (Euphagus carolinus), an uncommon songbird often associated with northern coniferous wetlands, has experienced a precipitous population decline since at least the early 20th century. Here, we provide the first analysis of breeding-habitat occupancy at the wetland scale and make recommendations for streamlined monitoring. We modeled occupancy and detectability as a function of site (i.e. habitat-based) and sampling (i.e. visit-specific) variables collected at 546 wetlands in northern New England, USA. Wetland occupancy (mean 6 SE ¼ 0.07 6 0.02 in randomly selected wetlands, and 0.12 6 0.02 in all wetlands surveyed) was best explained by variables …

Home Ranges Of Rusty Blackbirds Breeding In Wetlands: How Much Would Buffers From Timber Harvest Protect Habitat?, Luke L. Powell, Thomas P. Hodgman, William E. Glanz

Biology and Ecology Faculty Scholarship

We calculated the home ranges and core areas of 13 adult Rusty Blackbirds (Euphagus carolinus) in Maine to determine (1) the area requirements of breeding adults, (2) whether area requirements of the sexes and of colonial and noncolonial individuals differ, and (3) the proportion of the home range and core area that would be protected by a buffer of no logging of 50–100 m around occupied wetlands. Mean home ranges (37.5 ± 12.6 ha) and core areas (11.1 ± 2.8 ha) were large in comparison to those of other breeding icterids, and adults often foraged in multiple unconnected wetlands. Rusty …

Nest-Site Selection And Nest Survival Of The Rusty Blackbird: Does Timber Management Adjacent To Wetlands Create Ecological Traps?, Luke L. Powell, Thomas P. Hodgman, William E. Glanz, James D. Osenton, Caleb M. Fisher

Biology and Ecology Faculty Scholarship

Animals are subject to ecological traps when anthropogenic changes create habitat that appears suitable but when selected results in decreased fitness. The Rusty Blackbird (Euphagus carolinus) breeds in boreal wetlands and has declined by 85–95% over the last half century. We studied nest-site selection and daily nest survival rate (DSR) of 43 Rusty Blackbird nests in northern New England and evaluated whether regenerating logged areas adjacent to wetlands created ecological traps. Although nesting adults avoided high-canopied forests and selected areas with dense balsam fir (Abies balasmea) 1 to 3 m high, those characteristics were not associated …

Adaptive Changes In Life History And Survival Following A New Guppy Introduction, Swanne P. Gordon, David N. Reznick, Michael T. Kinnison, Michael J. Bryant, Dylan J. Weese, Katja Rasanen, Nathan P. Millar, Andrew P. Hendry

Biology and Ecology Faculty Scholarship

Numerous studies of wild populations have shown that phenotypic traits can change adaptively on short timescales, but very few studies have considered coincident changes in major fitness components. We here examine adaptive changes in life-history traits and survival rates for wild guppies introduced into new environments. Female life-history traits in the derived (Damier River) populations diverged from the ancestral (Yarra River) population, as a result of adaptation to predation regime (high vs. low) and other aspects of the local river. Moreover, some components of the derived Damier populations, particularly juveniles, now show higher survival in the Damier than do contemporary …

Additional Evidence That Juvenile Oyster Disease Is Caused By A Member Of The Roseobacter Group And Colonization Of Nonaffected Animals By Stappia Stellulata-Like Strains, K. J. Boettcher, B. J. Barber, J. T. Singer

Biology and Ecology Faculty Scholarship

Juvenile oyster disease (JOD) causes significant annual mortalities of hatchery-produced Eastern oysters, Crassostrea virginica, cultured in the Northeast. We have reported that a novel species of the α-proteobacteria Roseobacter group (designated CVSP) was numerically dominant in JOD-affected animals sampled during the 1997 epizootic on the Damariscotta River, Maine. In this study we report the isolation of CVSP bacteria from JOD-affected oysters during three separate epizootics in 1998. These bacteria were not detected in nonaffected oysters at the enzootic site, nor in animals raised at a JOD-free site. Animals raised at the JOD enzootic site that were unaffected by JOD were …

Biological Inventories Of Schoodic And Corea Peninsulas, Coastal Maine, 1996, Willaim E. Glanz, Bruce Connery, Norman Famous, Glen Mittelhauser, Melissa Perera, Marcia Spencer-Famous, Guthrie Zimmerman

Biology and Ecology Faculty Scholarship

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, …

Use Of Antibacterial Agents To Elucidate The Etiology Of Juvenile Oyster Disease (Jod) In Crassostrea Virginica And Numerical Dominance Of An Α- Proteobacterium In Jod-Affected Animals, Katherine J. Boettcher, Bruce J. Barber, John T. Singer

Biology and Ecology Faculty Scholarship

Since 1988, juvenile oyster disease (JOD) has resulted in high seasonal losses of cultured Eastern oysters (Crassostrea virginica) in the Northeast. Although the cause of JOD remains unknown, most evidence is consistent with either a bacterial or a protistan etiology. For the purpose of discerning between these hypotheses, the antibacterial antibiotics norfloxacin and sulfadimethoxine-ormetoprim (Romet-B) were tested for the ability to delay the onset of JOD mortality and/or reduce the JOD mortality of cultured juvenile C. virginica. Hatchery-produced C. virginica seed were exposed in triplicate groups of 3,000 animals each to either norfloxacin, sulfadimethoxine-ormetoprim, or filter-sterilized seawater (FSSW) and deployed …

Multiplex Reverse Transcriptase Pcr Assay For Simultaneous Detection Of Three Fish Viruses, K. Williams, S. Blake, A. Sweeney, J. T. Singer, B. L. Nicholson

Biology and Ecology Faculty Scholarship

A multiplex reverse transcriptase (RT)-PCR assay was developed for the simultaneous detection of three different fish viruses: infectious pancreatic necrosis virus (IPNV), infectious hematopoietic necrosis virus (IHNV), and viral hemorrhagic septicemia virus (VHSV). The sensitivity levels of the multiplex RT-PCR assay were 100, 1, and 32 50% tissue culture infective doses/ml for IPNV, IHNV, and VHSV, respectively.

Assessment And Choice: An Operant Simulation Of Foraging In Patches, John P. Roche, D. Alan Stubbs, William E. Glanz

Biology and Ecology Faculty Scholarship

Pigeons were presented with an operant simulation of two prey patches using concurrent random ratio schedules of reinforcement. An unstable patch offered a higher initial reinforcement probability, which then declined unpredictably to a zero reinforcement probability in each session. A stable patch offered a low but unvarying reinforcement probability. When the reinforcement probability declined to zero in a single step, the birds displayed shorter giving-up times in the unstable patch when the ratio between the initial reinforcement probabilities in the unstable and stable patches was greater and when the combined magnitude of the reinforcement probabilities in the two patches was …