Browsing by Subject "Hybrid poplar plantations"

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    Bird Usage of Hybrid Poplar Plantations Annual Progress Report 1996
    (University of Minnesota Duluth, 1997) Hanowski, JoAnn M; Niemi, Gerald J
    We continued to collect baseline data on the large plantations that have been established in the Alexandria area. Three sites have been surveyed for four years, six sites for three years, and four sites f.or two years. We observed a linear growth in mean numbers of individuals and species on plantations as they have aged from one to six years. Species diversity has plateaued after five years on two sites. Plantations that had partial tree failure in previous years had greater species diversity. This was expected because these sites have two or three ages of trees present on the site and were more heterogeneous in the bird habitat they provided. Species turnover rates were 57% for plantations that aged from one to two years and were 53% for plantations that aged from two to three years. The largest proportion of bird individuals in plantations in the first six years were short-distance migrants. Numbers of individuals that migrate long-distances to Central and South America increased slightly as the plantations aged. Very few permanent resident birds were found in plantations at any age. Most individuals observed in the plantations at all ages were ground feeding birds associated with open field and pasture habitats. Very few foliage gleaners individuals and those associated with forested habitats were observed in the plantations at any age. Numbers of shrub birds and those that eat seeds increased as the plantations have grown. Studies were again (repeated from 1995) conducted on predation rates of artificial bird nest~ to test the hypothesis that predation rates in forests and grasslands adjacent to plantations are not affected by distance to the edge of the plantation. Data collected on predation rates this past summer support the alternative hypothesis that predation rates are independent of habitat type and distance from edge of plantation. We found that predations rates were site specific and were likely affected by local predator populations. These results support conclusions made from similar studies collected in 1995. The geographic information system (GIS) that included land cover types within a 2-3 mile radius of each plantation in the Alexandria area (for details see small mammal report) was completed. Canonical correspondence analyses (CANOCO) on the plantations established after or during 1994 indicated that the landscape surrounding many plantations was similar and was dominated by cropland. Exceptions to this were the Kreyer and Nelson sites which had .more water, woodland, and pasture (Kreyer) and wet and dry wildland (Nelson) in the surrounding landscape. Bird species such as the Sedge Wren, Mallard, Common Yellowthroat, Ring-necked Pheasant, Blue-winged Teal found within the Nelson site relected the presence of the adjacent wet and dry wildland habitat. The Chipping Sparrow, Eastern Bluebird, Grasshopper Sparrow and Vesper Sparrow found in the Kreyer site reflected the composition of the surrounding forest and pasture habitat.
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    Bird Usage of Hybrid Poplar Plantations Annual Progress Report 1997
    (University of Minnesota Duluth, 1998) Hanowski, JoAnn M; Niemi, Gerald J
    'We continued to collect baseline data on the large plantations that have been established in the Alexandria area. Three sites have been surveyed for four years, six sites for three years, and four sites for two years. We continued to see a general pattern of an increase in species diversity and overall abundance as plantations have aged from one to five years. Older plantations (six and seven years) had fewer individuals than age five plantations, but this could be attributed to the fewer number of plantations that we have surveyed in the older age categories. Individual species observed on plantations indicated that open country birds continued to dominate the younger plantation community and early-successional species were most common on the three to five year old sites. Forest edge species were present on two older plantations but were also recorded on several four year old plantations. Very few forest species were observed in plantations of any age. Species turnover rates for individual sites indicated that community composition is unstable. Turnover was generally lower on sites after they have reached age five and higher on sites up to age four. The relatively high rate for the Belle River site from 1996 to 1997 is difficult to interpret, but could indicate that the community is changing from an early- successional species composition to a community that has more forest birds. Additional data are needed to confirm this observation. The highest proportion of individuals observed in the plantations of all ages were seed and insect eaters that feed on the ground. Based on the habitat guild summaries, it is evident that birds that prefer open fields and meadows dominated the bird community from ages 1 to 4. Bird species that prefer wet shrub, open wetland, or aquatic habitats were present in small numbers in plantations of all ages. The presence of these bird species on plantations were likely due to the influence of surrounding landuse types or by small wetland inclusions within the plantations. At age five and six a few species that occupy deciduous forests began to colonize the plantations. The largest proportion of bird species that occurred on plantations in the first six years were short-distance migrants. Very few resident birds were found in plantations at any age. Data collected on predation rates this past summer indicate that predation rates are independent of habitat type (including the plantation). For example, predation rates in plantations averaged 20% and the adjacent CRP rate was 10%. In addition, average rate for forests adjacent to plantations was 25% compared to 20% in the plantations. We have developed a geographic information system (GIS) that includes land cover types within a 2-3 mile radius of each plantation in the Alexandria area. Information gathered on birds over the past six years will be used as inputs for a geographical model to predict bird responses to plantation development. Initial values for bird species to be implemented into the model were calculated. Landuse change simulation models will be run to predict bird changes in response to plantation development and growth in this region.
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    Bird Usage of Hybrid Poplar Plantations Five Year Report 1992-1996
    (University of Minnesota Duluth, 1997) Hanowski, JoAnn M; Niemi, Gerald J
    Our efforts over the past five years have focused on one overall objective; to understand the habitat value of hybrid poplar plantations to breeding and migrating birds. Several objectives, with testable hypotheses were developed to address this overall objective. These hypotheses revolve around three central themes. The first is to determine how habitat changes with 1) plantation age, 2) size of plantation, 3) within plantation habitat, and 4) landscape context. The second set of hypotheses address the impacts of converting existing land to hybrid poplar considering; 1) type of habitat replaced, 2) landscape composition surrounding plantation, 3) within plantation plantings to enhance wildlife habitat value, and 4) affects of plantation on surrounding bird communities including assessment of predation events. Thirdly, we are focusing our efforts towards modeling these data spatially. Information required for these models include; 1) size of plantation, 2) landscape composition, 3) growth rates of trees, and 4) bird species composition at different stages of plantation succession.
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    Occurrence of Bird Species on Hybrid Poplar Plantations and Adjacent Land Uses in the North-Central U.S.
    (University of Minnesota Duluth, 1996) Hanowski, JoAnn M
    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.