Natural Resources Research Institute Technical Report

We have been studying songbirds and small mammals occupying hybrid poplar plantations in the north-central United States for the past several years. The overall objective of this project is to evaluate the possible biodiversity implications of large-scale woody biomass development, and to provide a basis for managing plantations with biodiversity goals in mind. Results of our initial studies on songbirds and small mammals are described in Christian et al. (1997), including patterns of occurrence and abundance on plantations and adjacent land use types. In that study, the occurrence of individual bird species was inconsistent across plantations. In addition, the abundance of many species on plantations was extremely low. For these reasons, Christian et al. (1997) presented and analyzed abundance data only for major migration guilds (long-distance migrants, short-distance migrants, and permanent residents) of birds, and not for individual species

Effect of Sewage Effluent on Bird Abundance and Species Composition in a Northern Minnesota Wetland

Bird abundance was monitored before (1985 and 1987) and after (1989) sewage wastewater effluent was added to a northern Minnesota wetland. Community parameters (i.e., number of individuals and species richness) varied annually, but, overall bird communities in 1985 and 1989 were more similar to each other than they were to the 1987 community. Relative abundance of 35 bird species was unchanged between years and species abundance ranks were not different between years. Distribution of numbers of individuals (relative percent) within nesting and foraging guilds (species that have similar nesting or feeding requirements) was similar among years. Numbers of species that increased or decreased between years was independent of nesting or foraging location (e.g., ground or above ground). Overall, no differences were detected in the bird community that could be attributed to addition of sewage effluent to the wetland up to two years after treatment (1987 to 1989)

Breeding Bird Populations in a Proposed Wetland Treatment Area of Northern Minnesota

A census of breeding bird populations was taken in a 40- hectare wetland near Biwabik, Minnesota, prior to the use of this wetland for phosphorus removal from treated wastewater. The wetland was comprised of four distinct habitat types: shrub swamp, black ash (Fraxinus nigra) forest, open coniferous forest, and closed coniferous forest. We used a line transect (about 4 km in length) to document species composition, relative species abundance, and habitat associations of the bird community. A total of816 individuals (mean= 204) and 45 species (mean = 34) were observed during four censuses in June and July, 1985. Two distinct bird communities were present in this wetland: those associated with ombrotrophic habitats (shrub swamp and ash forest) and those present in mincrotrophic habitats (open and closed coniferous forest). The Nashville warbler ( Vermivora ruficapilla) was the most common species in the wetland and also the only species that occurred in both minerotrophic and ombrotrophic habitats. The pre-impact data collected will allow assessment of the relative impact of adding sewage effluent to this wetland and the subsequent effect on bird species and populations

Effects of Two (Diptera: Culicidae) Mosquito Control Agents on Growth and Reproduction of Red-Winged Blackbirds (Agelaius phoeniceus)

We compared red-winged blackbird (Agelaius phoeniceus) reproductive success and nestling growth in 1988 in 10 wetland site treated with methoprene and 10 sites treated with Bacillus thuringiensis israelensis (Bti) to 30 sites that had never received any mosquito (Diptera: culicidae) control treatment. No differences were detected between reference and treatment sites for clutch size, egg volume, growth rates, or fledge weight. The probability that an egg survived to the nestling stage was greater in methoprene-treated than reference sites. No other differences were detected among sites for reproductive success estimated using the Mayfield method. We conclude that treatment of the wetlands with methoprene or Bti did not directly or indirectly affect red-winged blackbird growth or reproduction within the first two years after treatment

Breeding Bird Communities Across an Upland Disturbance Gradient in the Western Lake Superior Region

The coastal region of western Lake Superior to examine relationships to human land use. Eighty-four species were detected and 50 were abundant enough to be included in data analysis. Monotonic quadratic regression models were constructed for these 50 species by using species counts as the dependent variable and the proportion of human conversion of the landscape (residential, agriculture, and commercial/industrial land uses) within each study area as the independent variable. Twenty-seven bird species had significant regressions (P < 0.05), 18 of which generally avoided areas developed by humans and 9 of which were attracted to development. De-trended correspondence analysis using counts of these 27 bird species was used to investigate multivariate, community responses to development. The first DCA axis was interpreted as a gradient from urban avoiding to urban exploiting bird species and was strongly correlated with land cover variables related to human development. Our results advance the idea that breeding bird communities can be used as indicators of ecological condition and can diagnose potential causes for changes in these conditions. Further, our study points out the usefulness of bird monitoring data in regional planning efforts that incorporate goals for maintaining native biological diversity

Environmental Indicators for the Coastal Region of the U.S. Great Lakes

The goal of this research collaboration was to develop indicators that both estimate environmental condition and suggest plausible causes of ecosystem degradation in the coastal region of the U.S. Great Lakes. The collaboration consisted of 8 broad components, each of which generated different types of environmental responses and characteristics of the coastal region. These indicators included biotic communities of amphibians, birds, diatoms, fish, macroinvertebrates, and wetland plants as well as indicators of polycyclic aromatic hydrocarbon (PAH) photo-induced toxicity and landscape characterization. These components are summarized below and discussed in more detailed in 5 separate reports (Section II). Stress gradients within the U.S. Great Lakes coastal region were defined from 207 variables (e.g., agriculture, atmospheric deposition, land use/land cover, human populations, point source pollution, and shoreline modification) from 19 different data sources that were publicly available for the coastal region. Biotic communities along these gradients were sampled with a stratified, random design among representative ecosystems within the coastal zone. To achieve the sampling across this massive area, the coastal region was subdivided into 2 major ecological provinces and further subdivided into 762 segment sheds. Stress gradients were defined for the major categories of human-induced disturbance in the coastal region and an overall stress index was calculated which represented a combination of all the stress gradients. Investigators of this collaboration have had extensive interactions with the Great Lakes community. For instance, the Lake Erie Lakewide Area Management Plan (LAMP) has adopted many of the stressor measures as integral indicators of the condition of watersheds tributary to Lake Erie. Furthermore, the conceptual approach and applications for development of a generalized stressor gradient have been incorporated into a document defining the tiered aquatic life criteria for defining biological integrity of the nation’s waters. A total of 14 indicators of the U.S. Great Lakes coastal region are presented for potential application. Each indicator is summarized with respect to its use, methodology, spatial context, and diagnosis capability. In general, the results indicate that stress related to agricultural activity and human population density/development had the largest impacts on the biotic community indicators. In contrast, the photoinduced PAH indicator was primarily related to industrial activity in the U.S. Great Lakes, and over half of the sites sampled were potentially at risk of PAH toxicity to larval fish. One of the indicators developed for land use/land change was developed from Landsat imagery for the entire U.S. Great Lakes basin and for the period from 1992 to 2001. This indicator quantified the extensive conversions of both agricultural and forest land to residential area that has occurred during a short 9 year period. Considerable variation in the responses were manifest at different spatial scales and many at surprisingly large scales. Significant advances were made with respect to development of methods for identifying and testing environmental indicators. In addition, many indicators and concepts developed from this project are being incorporated into management plans and U.S. 8 EPA methods documents. Further details, downloadable documents, and updates on these indicators can be found at the GLEI website - http://glei.nrri.umn.edu

Natural Resources Research Institute Technical Report

Breeding bird surveys were conducted for the third consecutive year in the Cornish Hardwood management area (CHMA), located in northeast Aitkin County. The objectives of this project are to: 1) establish a long-term breeding bird monitoring program in the CHMA to detect annual changes in species abundances, 2) determine whether bird community composition and species abundances are affected by uneven-aged management, and 3) compare the bird community in the CHMA with other northern hardwood stands in northern Minnesota. This report provides a summary of bird surveys completed in June of 2000 and also compares 1998, 1999 and 2000 survey results

Natural Resources Research Institute Technical Report

The Cornish Hardwood management area (CHMA), located in northeast Aitkin County is managed by Aitkin County forestry department and Minnesota Department of Natural Resources in an uneven-aged format. The forestry goals for this area are to provide wood resources for local industry and to promote regeneration and growth of high value hardwood trees by maintaining this forest type throughout each rotation. Northern hardwood forests provide habitat for a variety of breeding bird species, including several long-distant migrants. Although, response of breeding birds to successional forest stages from clearcut to mature stand ages are relatively well known and predictable for northern Minnesota forests, breeding bird response to uneven-aged management in northern hardwoods has not been studied in Minnesota. Our objectives were to: 1) establish a long-term breeding bird monitoring program in the CHMA to detect annual changes in species abundances, 2) determine whether bird community composition and species abundances are affected by uneven-aged management, and 3) compare bird community in the CHMA with other northern hardwood stands in northern Minnesota. Twenty-six individual stands that were greater than 40 acres were selected for monitoring. Eight stands were harvested within the past 10 years (managed), eight stands are in the management area, but have not been recently managed (unmanaged), and ten sites were located in Savannah Portage State Park. One breeding bird survey was conducted at each point with an unlimited radius 10 minute count point count. A total of 25 bird species were observed in 26 stands (52 points). On average, we observed about 22 individuals and 7 to 8 species in each stand (total of two point counts). No differences were detected in bird communities among management types. Two of the 15 species tested with analysis of variance indicated a significant difference (P < 0.05) in abundance among management types. The Chestnut-sided Warbler and Winter Wren were more abundant in the managed than in the unmanaged or reference sites. Both of these species are associated with habitat features that occur shortly after forest management activities (shrubs or slash piles). A cluster analysis with bird species showed that bird community composition was not different among management types. Overall bird communities in all stands sampled regardless of management history were similar. This result indicates that uneven-aged management such as the type that has been lone at CHMA does not result in a forest structure that is different than what currently exists in other northern hardwood stands in this region. This result is similar to what we have found previously for other “old-growth” northern hardwood stands in the State. A species that was absent in northern hardwood stands in this region was the Black-throated Blue Warbler. This species is rarely found in northern hardwoods in north central Minnesota but occurs in selected northern hardwood stands in northeast Minnesota, primarily in the Lake Superior highlands. A study on the Black-throated Blue Warbler in northeast Minnesota in 1998 found that the species prefers northern hardwood stands with a shrub understory. In areas where there are few shrubs, the species was primarily associated with small gaps (in the range of 0.05 to 0.10 ha) in the canopy that have resulted from blowdowns. The natural disturbance regime for northern hardwoods in this region was windstorms which occur every few decades and create small forest gaps by blowing down senescent or weak and hollow trees. It is possible that the Black-throated Blue Warbler historically responded to habitat that was created by these gaps and moved across the landscape as new patches were created and old patches became unsuitable. It may be possible maintain the objectives for forest management in the CHMA by completing harvests that would result in the creation of small gaps. Another recommendation would be to chose harvest equipment that would have less impact on the understory vegetation (e.g., result in less skidding of trees). These management suggestions will not only provide more suitable habitat for avian species that require shrubs and saplings, but also a population of seedlings and saplings for future recruitment into the canopy.Natural Resources Research Institute, University of Minnesota Dulut

Natural Resources Research Institute Technical Report

Report to Aitkin County Forestry Department; Minnesota Department of Natural Resources, Non-game Division, Grand Rapids, MNBreeding bird surveys were conducted for the second consecutive year in the Cornish Hardwood management area (CHMA), located in northeast Aitkin County. The objectives of this project are to: 1) establish a long-term breeding bird monitoring program in the CHMA to detect annual changes in species abundances, 2) determine whether bird community composition and species abundances are affected by uneven-aged management, and 3) compare the bird community in the CHMA with other northern hardwood stands in northern Minnesota. This report provides a summary of bird surveys completed in June of 1999 and also compares 1998 and 1999 survey results. Please refer to the 1998 report for more detail on methods and rationale for this study. Twenty-six individual stands that were greater than 40 acres were selected for monitoring. Eight stands were harvested within the past 10 years (managed), eight stands are in the management area, but have not been recently managed (unmanaged), and ten sites were located in Savannah Portage State Park. One breeding bird survey was conducted at each point with an unlimited radius 10 minute count point count in Junes of 1998 and 1999. A total of 25 bird species were observed in 26 stands (52 points) in 1998 and 32 species were counted in 1999. Over both years, a total of 37 species have been observed in this area. On average, we observed about 22 individuals and 7 to 8 species in each stand (total of two point counts) in 1998 and a slightly higher number, about 25 individuals and 8 species in 1999. Results of a two-way analysis of variance for the bird community variables indicated that more (P < 0.001) total individuals were observed in 1999 than in 1998. In addition, we found a significant difference in number of species observed in stands with different management history. Here, unmanaged stands had fewer species (P < 0.01) than the managed or reference stands. Not one of the 8 species tested with two-way analysis of variance indicated a significant difference (P < 0.05) in abundance among management types or year. We found a significant interaction for year and treatment for the Scarlet Tanager. This test result indicated that the species abundance pattern on unmanaged sites was not consistent between 1998 and 1999. For example, more Scarlet Tanagers were observed on unmanaged sites in 1998 than in the other two management groups, but in 1999, this management type had the fewest number of individuals of this species. A cluster analysis with bird species showed that bird community composition was not different among management types or between years. Occurrence of uncommon species on individual sites was most likely the reason why some sites differed in their relative cluster position (or composition of cluster) between the two years. A species that was absent in northern hardwood stands in this region in 1998 but present in 1999 was the Black-throated Blue Warbler. This species is rarely found in northern hardwoods in north central Minnesota but occurs in selected northern hardwood stands in northeast Minnesota, primarily in the Lake Superior highlands. A recently completed study on the Black-throated Blue Warbler in northeast Minnesota applied in managing in 1999 will provide quantitative habitat information for this species that could be the CHMA for this hardwood dependent species.Natural Resources Research Institute, University of Minnesota Dulut