Abundance and habitat relationships of butterfly communities were examined at 15 sites divided into three different types of residential areas (n = 5 sites/type) in central Pennsylvania from May-September 1997. Seventeen species were noted at the 15 sites, with the two most abundant being non-native, cabbage whites (Pieris rapae, 69.2% of total) and orange sulfurs (Colias eurytheme, 10.0%). The most abundant native species was the monarch (Danaus plexippus, 7.5%). More butterfly species (n = 13 species) but a lower than expected number of individual butterflies of all species combined (P < 0.05) occurred in residential areas with established (homes > 30 years old) and native overstory trees than in the two other types of residential areas. Total species richness of butterflies was positively correlated with the number of homes per site (i.e., smaller lot size) (P < 0.05). On the other hand, the total number of butterflies of all species combined and the total number of cabbage whites were negatively correlated with the number of yards containing native overstory trees (P < 0.05). Compared to forested or agricultural landscapes in central Pennsylvania, the diversity and abundance of butterflies were relatively low in residential areas. In residential landscapes, however, a diverse butterfly community was characteristic of older, established neighborhoods characterized by smaller lot size and native overstory tree species. The planting of gardens containing both nectar sources and hostplants for butterflies will likely enhance their diversity and abundance in residential areas.
We surveyed birds during breeding, migratory, and wintering seasons in forest patches of two fragmented landscapes in the Valley and Ridge Province of south-central Pennsylvania during 1994–1996. Our objective was to examine presence of species in relation to forest-patch size (<2, 6–20, 40–150, and >1,500 ha) and extent of regional fragmentation. Several species, particularly long-distance migrants (e.g., Eastern Wood-pewee [Contopus virens], Red-eyed Vireo [Vireo olivaceus], Wood Thrush [Hylocichla mustelina], Worm-eating Warbler [Helmitheros vermivorum], and Scarlet Tanager [Piranga olivacea]), were more likely to occur in larger forest patches than in smaller patches during the breeding and spring-migratory seasons. Short-distance migrants (e.g., American Robin [Turdus migratorius], Gray Catbird [Dumetella carolinensis], and Eastern Towhee [Pipilo erythrophthalmus]), responded to fragmentation at a regional scale and were more commonly encountered in the more fragmented landscape, particularly during migratory periods. Species observed during fall migration were not influenced by patch size. The Pileated Woodpecker (Dryocopus pileatus) responded positively to patch size in all seasons, whereas the Song Sparrow (Melospiza melodia) was influenced negatively by patch size in three of four seasons. More research should be conducted at sites during winter and migration to corroborate these results and to examine the role patch size may have in long-term survivorship of migratory birds.
Farmstead shelterbelts are man-made habitats consisting of parallel rows of trees and shrubs designed to protect farmsteads from damaging winds, drifting snow and blowing soil, and to moderate the effects of wind, thereby reducing heat loss from humans, domestic animals, and farm buildings (Smith and Scholten 1980). These habitats may be viewed as small (generally <1 ha) islands surrounded by extensive fields of crops, pastures and natural prairies; however, despite their small size and isolation from other wooded habitats, shelterbelts are a source of food and song perches as well as roosting and nesting sites for a number of bird species (Orendurff 1941, Martin 1978). Avian communities in shelterbelts have been examined during the breeding season (Weiser and Hlavinka 1956; Cassel et al. 1966, 1967; Emmerich 1978; Martin 1978). However, with the exception of studies dealing with Mourning Doves (Zenaida macroura) (see Nelson 1976 for review), Ring-necked Pheasants (Phasianus colchicus) (e.g., Olson and Flake 1975) and Ferruginous Hawks (Buteo regalis) (Lokemoen and Duebbert 1976), little is known about the nesting ecology of many bird species breeding in shelterbelts. A study by Field (1971) represents the only published report giving the total number of nests per bird species. Her study dealt only with a portion of one shelterbelt where tree/shrub species used and height above ground of 75 nests of four bird species were noted. As part of an investigation of breeding-bird diversity in 69 shelterbelts, Martin (1978) examined 185 nests of eight species and noted tree/shrub species used, height above ground, lateral distance of nest from main stem, and distance of nest from top of tree/shrub. However, his study did not attempt to locate total nests per shelterbelt nor total nests per season. A determination of both the number of avian species nesting in farmstead shelterbelts and the abundance of nests per species is an initial and important step in assessing whether or not these small, narrow, agricultural habitats are valuable nesting areas or instead perhaps function to attract predators, hence reducing fledging success (see Gates and Gysel 1978). Moreover, because farmstead shelterbelts are restricted in size, the availability of nest-sites conceivably could be a limiting resource to birds. Thus, a knowledge of factors critical to nest-site selection would give a better understanding of how coexisting nesting species effectively exploit these islands (after Pianka 1973, Schoener 1974).
The Northern Goshawk (Accipiter gentilis) is a rare to uncommon woodland raptor in Pennsylvania. Although it is primarily a boreal species, the goshawk nests in Northern Hardwoods and Appalachian oak forests along the southern margin of its range in Pennsylvania. This study compared the nesting habitat of goshawks in Appalachian oak and Northern Hardwoods forests in Pennsylvania during the 1989-90 field seasons.
Seasonal dynamics and habitat relationships of avian populations and communities in farmstead shelterbelts were studied during 1978-80 in southern Minnesota. Eighty-seven species of birds were recorded, 14 of which were classified as being highly important; omnivores and granivores were predominant. Species richness (S) and species diversity (H') were similar in spring and summer, but were lower in autumn and winter. Species evenness (J') seldom varied among seasons, and no consistent pattern in total individuals of all species combined (N) occurred over seasons. Shelterbelts were segregated into 3 types based primarily on stability of S, J', and N during autumn and winter. Extent of perimeter and length of shelterbelts were associated more often with avian variables than was area of shelterbelts. Distance to wooded and oldfield habitats, distance to and number of proximal buildings, and percentage of croplands and pastures surrounding shelterbelts were important to associated avifauna. A concentration effect occurred in isolated shelterbelts; the greater the isolation, the more likely that certain species were encountered in a shelterbelt due to the paucity of similar habitat in the vicinity. Picea, Pinus, Populus, Ulmus, Acer, Fraxinus, and Lonicera were related to abundances of several avian species. Management recommendations include establishing shelterbelts that are >0.6 ha in area and 8 rows in width. Proper spacing within and between rows should be considered and a diversity of plantings should be used. Mowing and cultivation should be discontinued after the shelterbelt becomes established. Snags should be retained as nesting and foraging sites. Croplands, rather than pastures, should be positioned near shelterbelts. No-tillage or minimum tillage systems, a few rows of standing crops, food plots, and artificial feeders at farm homes are suggested. Shelterbelts can be designed to provide protection and beauty to the farmstead aswell as to benefit a variety of farmland avifauna. J. WILDL. MANAGE. 47(1):85-104 Farmstead shelterbelts are man-made habitats created by planting rows of trees and shrubs (hereafter also termed plantings) on the windward sides of farm homes and buildings. In intensively farmed regions of the Midwest, these small wooded islands (generally <1 ha) provide protection against wind and drifting snow, reduce energy and feed costs, and afford aesthetic beauty to farmsteads (Smith and Scholten 1980). Further, shelterbelts are of considerable importance to birds and other wildlife (Popowski 1976, Martin 1978). However, as a result of larger farms, increased mechanization, use of pivot irrigation systems, and other recent trends in the agricultural industry, the availability of farmstead shelterbelts and other permanent wildlife habitat is restricted (Vance 1976). For example, Griffith (1976) estimated that farmstead shelterbelts, field windbreaks, and other wooded habitats comprise <3% of the total area in the Great Plains. Aspects of the ecology of avifauna associated with farmstead shelterbelts have been examined. Rotzien (1963) and Yahner (1981) studied winter use of shelterbelts by birds. Weiser and Hlavinka (1956), Martin (1978, 1980), Martin and Vohs (1978), and Cassel and Wiehe (1980) investigated breeding and migratory communities in these habitats. Avian use of vertical strata and plantings during the annual cycle has been detailed (Yahner 1981b). Nest densities and nest-site selection also have been examined (Field 1971, Martin 1978, Yahner 1982a). Studies of avian communities in a variSPresent address: Forest Resources Laboratory, School of Forest Resources, The Pennsylvania State University, University Park, PA 16802. J. Wildl. Manage. 47(1):1983 85 This content downloaded from 157.55.39.215 on Tue, 30 Aug 2016 04:48:53 UTC All use subject to http://about.jstor.org/terms 86 AVIFAUNA IN FARMSTEAD SHELTERBELTS * Yahner ety of habitats usually have been conducted only during the breeding season, with little reference to nonbreeding times of the year (Kricher 1975); yet seasonal monitoring of bird communities is necessary for a better understanding of populations and habitat relationships (Dickson 1978). The objectives of my study were to (1) document seasonal trends in the dynamics of avian populations and community structure in farmstead shelterbelts, (2) examine the relationships between the habitat features describing dimensions, vegetation, and proximal land-uses of shelterbelts and the avian populations and communities using these habitats, and (3) develop effective management recommendations for landowners and agencies that either establish new or renovate older shelterbelts. I thank H. Scholten of the College of Forestry, University of Minnesota and C. L. Wilcox of the Rosemount Agricultural Experiment Station for cooperation with all aspects of the research. M. W. Weller and J. R. Kitts, Department of Entomology, Fisheries, and Wildlife, University of Minnesota and H. Scholten provided helpful comments on the manuscript. This study was supported by the Minnesota Agricultural Experiment Station and by grants from the Graduate School of the University of Minnesota, the National Rifle Association of America, and the Max McGraw Wildlife Foundation. This is Paper 11,826 of the Minnesota Agricultural Experiment Station, Scientific Journal Series, University of Minnesota, St. Paul.
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