Effects of human activities on birds across landscapes in the midwest.

摘要

Taking an interdisciplinary approach towards understanding the role of private landowners on birds, the main objectives of the study were to: (1) Discern the role of landowners' activities and perceptions towards birds on a selected group of three landscapes; (2) Test for differences in activities and perceptions across the rural-to-urban gradient comprising the three landscapes; (3) Aggregate results to the landscape level and, (4) Examine if the relative abundance and diversity of bird species across landscapes was related to landowner activities and human influences.; To address objectives 1 through 3 I surveyed all ∼1,700 private landowners living in three landscapes in Southeastern Michigan, where >90% of land is privately owned. The three landscapes represent urban, suburban, and rural landscapes based on their geographic locations, average land parcel sizes, and socio-demographic compositions. For the final objective I analyzed 402 landscapes across the entire Midwest.; Of the 969 landowners that responded (58.5% response rate), 920 (95%) carried out at least one activity (of eight measured) on their land that can have a potential impact on birds, with the average landowner carrying out four. Collectively, 66% of landowners fed birds, 46% provided bird houses, 26% had outdoor cats, 55% planted or maintained vegetation explicitly for birds, 49% applied fertilizer, 73% gardened, 72% landscaped, and 25% applied pesticides or herbicides. The number/landowner of bird feeders, bird houses, and outdoor cats was greatest in the rural landscape and least in the urban. However, densities (#/ha) of feeders, houses, and cats showed an inverse trend, with the greatest densities occurring in the urban landscape. In terms of perceptions, the typical landowner indicated that the number of birds had increased over time and that having bird diversity on their property was very important, but that they were only slightly willing to change their land use for the benefit of birds. Across the three landscapes there were significant differences in both the proportion and the magnitude of landowner activities as well as landowner perceptions towards birds. Aggregating all landowners indicates that a minimum of 25% to 40% of the landowners were involved in each of the eight activities.; Across all Midwest landscapes there was a negative relationship between avian diversity and (1) the number of housing units and (2) the amount of anthropogenic land cover. Most bird species investigated displayed significant relationships with the level of human influence on the landscape. (Abstract shortened by UMI.)