Bird Usage of Hybrid Poplar Plantations Annual Progress Report 1997

Abstract

'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.