Michael J. Hamas
Bio: Michael J. Hamas is an academic researcher from Central Michigan University. The author has contributed to research in topics: White-cedar & Homeothermy. The author has an hindex of 4, co-authored 5 publications receiving 79 citations.
TL;DR: In this paper, the authors test the hypothesis that northern Lake Huron influences the foraging behavior of Black-throated Green Warbler (Dendroica virens) during both migratory periods and the breeding season.
Abstract: The Great Lakes strongly influence local climate, vegetation, and animal com- munities, all of which are important to both migrating and breeding birds. This influence can be considerable during springtime in nearshore habitats, as onshore winds depress air temperatures, delaying development of shoreline vegetation relative to inland areas. These developmental differences also may affect abundance, distribution, activity, and growth of insect prey, resulting in spatially-related differences in foraging by birds. Here we test the hypothesis that northern Lake Huron influences the foraging behavior of Black-throated Green Warblers (Dendroica virens) during both migratory periods and the breeding season. We detected spatial variation in a number of variables we used to describe foraging, with most differences occurring during spring migration. We suggest that birds primarily varied foraging in response to spatial differences in prey resulting from microclimatic influences of nearby Lake Huron. We also suggest that emerging aquatic insects in shoreline habitats, primarily midges (Diptera: Chironomidae), are important to birds and propose that this
TL;DR: For example, this article found that the American Redstart (Setophaga ruticilla) forages differently in shoreline habitats relative to inland habitats of similar vegetation composition and performed more sally strikes than birds at the shoreline.
Abstract: Lowland coniferous forests adjacent to northern Lake Huron provide important stopover habitat for landbirds during spring migration. Large numbers of aquatic insects emerging from nearshore waters of northern Lake Huron appear to be an important food source. In this study we compared the foraging behavior of a long-distance landbird migrant, the American Redstart (Setophaga ruticilla), in areas with high densities of emergent aquatic insects to areas with few or no emergent aquatic insects to assess the significance of these arthropods as an early spring food source. Redstarts foraged differently in shoreline habitats relative to inland habitats of similar vegetation composition. Both males and females gleaned significantly more in shoreline habitats as compared to inland areas of similar vegetation composition, and inland birds performed more sally strikes than birds at the shoreline. Both sexes also varied the use of tree species in which they foraged. Redstarts used northern white cedar (Thuja occidentalis) more at shoreline than inland, while inland redstarts foraged in deciduous trees more than at the shoreline. We suggest that differences in foraging between shoreline and inland locations were responses to differences in prey types and abundance, most notably the presence of emergent aquatic insects (Diptera: Chironomidae) in shoreline habitat. Our results complement those of previous work, suggesting that midges provide a critical early season resource for landbirds migrating through Michigan's eastern Upper Peninsula during spring. Received 30 September 2003, accepted 26 March 2004. During spring and early summer in temper- ate North America, large numbers of aquatic insects that have metamorphosed into sexually mature adults often amass in terrestrial habi- tats adjacent to riparian and lacustrine systems (Armitage 1995, McCafferty 1998). These in- vertebrates are relatively weak fliers (e.g., Ko- vats et al. 1996) and tend to be restricted to nearshore terrestrial habitats. In Michigan's eastern Upper Peninsula, midges (Diptera: Chironomidae) are the predominant aquatic arthropods when migratory landbirds stop during spring migration. These invertebrates swarm profusely in shoreline areas while be- ing virtually nonexistent inland (DNE unpubl. data). Recent evidence suggests that lowland co- niferous forests adjacent to northern Lake Hu- ron provide important stopover habitat for spring migrants. More landbirds are found in 1
TL;DR: Coastal areas within the Great Lakes region provide critical stopover habitat for landbird migrants and should be a focus of conservation efforts, especially given the increasing development pressure that threatens these areas.
Abstract: The distribution of landbirds during migration in forested landscapes of eastern North America is poorly known. We describe (1) the distribution of landbirds in northern white cedar (Thuja occidentalis) dominated forests as a function of distance from northern Lake Huron in Michigan during spring and autumn migration, and (2) discuss factors that may affect the distribution of these migrants. Both long- and short-distance migrants in spring and fall were concentrated within 0.4 km of the Lake Huron shoreline. This pattern was particularly pronounced during spring when aquatic-hatched insects such as midges and their predators (e.g., spiders) are most common and occur in largest numbers near the shoreline. Both long- and short-distance migrant abundance was associated with midge abundance, after controlling for date, during spring migration but not during fall migration. Migrants may concentrate near the shoreline because of the barrier effect of Lake Huron and relatively abundant food resources, ...
TL;DR: The ability to maintain constant TB at low TA improved with increased growth and feather development, and physiological endothermy was established at 16 days after hatching, and the timing of effective homeothermy appears to be influenced by a combination of adaptations that contribute to optimal reproductive success.
Abstract: 1. 1. At 1 wk after hatching, nestling belted kingfishers (Megaceryle alcyon) remain naked and are incapable of regulating body temperature (TB) when exposed to low ambient temperatures (TA) in the laboratory. 2. 2. The ability to maintain constant TB at low TA improved with increased growth and feather development, and physiological endothermy was established at 16 days after hatching. 3. 3. In the nest, naked nestlings established effective homeothermy at 6 days after hatching, although adults had ceased brooding. 4. 4. In addition to increased growth and feather development, the timing of physiological endothermy in hole-nesting birds may be affected by a longer nestling period than open nesting species. However, the timing of effective homeothermy appears to be influenced by a combination of adaptations that contribute to optimal reproductive success.
TL;DR: The Belted Kingfisher (Ceryle alcyon) exhibits territorial behavior during breeding and on the wintering grounds as mentioned in this paper, however, behavior during migration is poorly documented.
Abstract: The Belted Kingfisher ( Ceryle alcyon ) exhibits territorial behavior during breeding and on the wintering grounds. However, behavior during migration is poorly documented. Here, I report on kingfishers exhibiting territorial behavior during fall migration along the shoreline of northern Lake Huron, Michigan.
Virginia Tech College of Natural Resources and Environment1, University of Wisconsin-Madison2, University of California, Santa Barbara3, State University of New York System4, National Wildlife Federation5, University of Michigan6, Saint Mary's University7, The Nature Conservancy8, University of Windsor9, Great Lakes Commission10, Michigan State University11, University of Minnesota12, University of New Hampshire13, Great Lakes Institute of Management14, National Oceanic and Atmospheric Administration15, Grand Valley State University16
TL;DR: Joint spatial analysis of stressors and ecosystem services can provide a critical foundation for maximizing social and ecological benefits from restoration investments and find that many important areas for fisheries and recreation are subject to high stress, indicating that ecosystem degradation could be threatening key services.
Abstract: With increasing pressure placed on natural systems by growing human populations, both scientists and resource managers need a better understanding of the relationships between cumulative stress from human activities and valued ecosystem services. Societies often seek to mitigate threats to these services through large-scale, costly restoration projects, such as the over one billion dollar Great Lakes Restoration Initiative currently underway. To help inform these efforts, we merged high-resolution spatial analyses of environmental stressors with mapping of ecosystem services for all five Great Lakes. Cumulative ecosystem stress is highest in near-shore habitats, but also extends offshore in Lakes Erie, Ontario, and Michigan. Variation in cumulative stress is driven largely by spatial concordance among multiple stressors, indicating the importance of considering all stressors when planning restoration activities. In addition, highly stressed areas reflect numerous different combinations of stressors rather than a single suite of problems, suggesting that a detailed understanding of the stressors needing alleviation could improve restoration planning. We also find that many important areas for fisheries and recreation are subject to high stress, indicating that ecosystem degradation could be threatening key services. Current restoration efforts have targeted high-stress sites almost exclusively, but generally without knowledge of the full range of stressors affecting these locations or differences among sites in service provisioning. Our results demonstrate that joint spatial analysis of stressors and ecosystem services can provide a critical foundation for maximizing social and ecological benefits from restoration investments.
TL;DR: The management and rehabilitation of freshwater shore zones could be improved by better use of ecological knowledge, and what is known about their ecological functioning is summarized.
Abstract: Freshwater shore zones are among the most ecologically valuable parts of the planet, but have been heavily damaged by human activities. Because the management and rehabilitation of freshwater shore zones could be improved by better use of ecological knowledge, we summarize here what is known about their ecological functioning. Shore zones are complexes of habitats that support high biodiversity, which is enhanced by high physical complexity and connectivity. Shore zones dissipate large amounts of physical energy, can receive and process extraordinarily high inputs of autochthonous and allochthonous organic matter, and are sites of intensive nutrient cycling. Interactions between organic matter inputs (including wood), physical energy, and the biota are especially important. In general, the ecological character of shore zone ecosystems is set by inputs of physical energy, geologic (or anthropogenic) structure, the hydrologic regime, nutrient inputs, the biota, and climate. Humans have affected freshwater shore zones by laterally compressing and stabilizing the shore zone, changing hydrologic regimes, shortening and simplifying shorelines, hardening shorelines, tidying shore zones, increasing inputs of physical energy that impinge on shore zones, pollution, recreational activities, resource extraction, introducing alien species, changing climate, and intensive development in the shore zone. Systems to guide management and restoration by quantifying ecological services provided by shore zones and balancing multiple (and sometimes conflicting) values are relatively recent and imperfect. We close by identifying leading challenges for shore zone ecology and management.
01 Jan 1993
TL;DR: In this article, the authors explored large-scale migratory responses of land birds encountering the Great Lakes as revealed by weather surveillance radars (WSR-88D) and two smaller specialized radars.
Abstract: The Great Lakes and nearby agricultural midwestern United States together represent a geographical challenge to migratory land birds during flight and stopover. We explored large-scale migratory responses of land birds encountering the Great Lakes as revealed by weather surveillance radars (WSR-88D) and two smaller specialized radars. Those responses reveal comprehensive landscape- or regional-scale migratory patterns that would otherwise have been difficult to infer. Analysis of radar echoes showed birds crossed the Great Lakes in large numbers, although we also found evidence of birds avoiding lake crossing in some locations. Around dawn, birds over water in numerous locations frequently exhibited an increase in migratory height (dawn ascent) and often an accompanying reorientation toward nearest land if they were within ∼28 km of shore. Those behavioral responses to the Great Lakes influence the resulting distribution of birds stopping over in the intervening terrestrial landscapes.
TL;DR: The soundscape power metrics and the visualizations of the soundscape produced in this study should provide a means of rapidly synthesizing large numbers of recordings into meaningful patterns to examine soundscape change.
Abstract: article i nfo Soundscape Ecology is an emerging area of science that does not focus on the identification of species in the soundscape butattempts to characterize sounds byorganizingtheminto thoseproducedbybiologicalorganisms such as birds, amphibians, insects or mammals; physicalenvironmental factors such as thunder, rainfall or wind; and sounds produced by human entities such as airplanes, automobiles or air conditioners. The soundscape changes throughout the day and throughout the seasons. The soundscape components that create the sound occur at different frequencies. A set of metrics termed soundscape power was computed and visualized to exam- ine the patterns of daily and seasonal change in the soundscape. Automated recorders were used to record soundscape samples every half hour for one minute duration from six sites on an uninhabited island in Twin Lakes located near Cheboygan in Michigan's northern Lower Peninsula. Each recording was divided into 1 kHz frequency intervals and visualization tools were used to examine the soundscape power in each interval during 48 half-hour time segments from April-October for four consecutive years. Daily pat- terns of soundscape power change were also examined during the seven month sample period. To synthesize the data set, three dimensional contour plots were used to visualize day of the year (x), time of day (y) and soundscape power (z) for several frequency intervals. A further synthesis was developed to visualize soundscape change using a Normalized Difference Soundscape Index (NDSI) which is a ratio of low to high frequencies. The visualization of the soundscape revealed discrete patterns in the soundscape including striking changes in the time of the occurrence of dawn and dusk choruses. The patterns in the soundscape were remarkably similar overthefour-yearinvestigation.Soundscapepowerinthelowerfrequency examined(1-2 kHz)wasadominant featureofthesoundscapeatTwinLakesandthelowfrequencysoundscapepowerwasnegativelycorrelatedwith higher frequency sounds. The soundscape power metrics and the visualizations of the soundscape produced in this study should provide a means of rapidly synthesizing large numbers of recordings into meaningful patterns to examine soundscape change. Thisisespecially useful because of theneedto develop indicesof ecologicalmetricsbasedon soundscape attributes to assist resource managers in making decisions about ecosystem integrity. Visualization can also be of immense benefittoexamine patternsinlargesoundscape time seriesdata sets thatcan be producedbyautomat- ed recording devices.