David J. Flaspohler

RELATIONSHIP BETWEEN NEST SUCCESS AND CONCEALMENT IN TWO GROUND-NESTING PASSERINES

Abstract We examined vegetation characteristics around nest sites of the Hermit Thrush (Catharus guttatus) and Ovenbird (Seiurus aurocapillus) for three summers in the northern-and mixed-hardwood forests of northern Wisconsin and the Upper Peninsula of Michigan to test the hypothesis that nests with greater concealment are less vulnerable to depredation. Because these two ground-nesting passerines differ in terms of nest structure and behavior near the nest, they present an opportunity to examine how these two factors influence reproductive success in sympatric species. Depredation was the most common source of nest failure for both species, with Ovenbirds having higher nest success for data pooled across years. Side (but not overhead) concealment was correlated positively with nest success for the Hermit Thrush but not for the Ovenbird. Side and overhead concealment did not differ between the Hermit Thrush and Ovenbird. We found a substantial proportion of nests in ground pine (Lycopodium obscurum). Hermit Thrush, but not Ovenbird nests in ground pine were significantly more concealed than nests in other sites both from the side and overhead. Vegetative concealment at the nest microsite may be more important to the open-cup nest of the Hermit Thrush than to the domed nest of the Ovenbird. Because flushed Ovenbirds perform a distraction display and Hermit Thrushes do not, Ovenbirds may have an incentive to choose nest sites that offer less than maximum concealment.

RIPARIAN AND UPLAND BREEDING-BIRD ASSEMBLAGES ALONG HEADWATER STREAMS IN MICHIGAN'S UPPER PENINSULA

Abstract Comparative studies of riparian and upland bird communities have focused primarily on larger streams (greater than second order). We examined breeding-bird assemblages in relation to their proximity to small head-water streams in northern hardwood forests of the Otter River watershed in Michigans Upper Peninsula, USA. At 10 study sites, we used fixed-radius point counts to survey bird assemblages and measure forest habitat characteristics along riparian and upland transects. Forest structure and composition differed between riparian and upland areas, with more conifer stems and higher conifer basal area on riparian transects. We detected 46 bird species during 1999 and 2000. During each year, total bird abundance was similar for riparian and upland areas, whereas bird species richness and evenness was higher in riparian areas. When we pooled bird species by foraging guild, we found that foliage-gleaning birds were more abundant in riparian areas. We found 12 bird species exclusively in riparian areas and only 2 species exclusively in the uplands. The northern parula (Parula americana) and Black-burnian warbler (Dendroica fusca) were among 5 species more abundant on riparian transects, whereas the least flycatcher (Empidonax minimus) and red-eyed vireo (Vireo olivaceus) were among 5 species more abundant on upland transects. Although the vegetative gradient between riparian and upland habitat was subtle along these first- and second-order streams, breeding-bird assemblages differed between riparian and upland forests. This suggests that individual bird species respond to vegetative features of even narrow riparian areas. Managers working in northern and mixed-hardwood forests therefore should consider maintaining habitat diversity in the form of native conifers, even on the smallest first-order streams.

Diversity, productivity and landscape-level effects in North American grasslands managed for biomass production

Expanding markets for bioenergy will increasingly shape the composition and configuration of crop production. Growing interest in second-generation biofuels (e.g., lignocellulosic ethanol) is driving a discussion about the most productive and appropriate cropping systems. Interest in perennial grasslands as a bioenergy source has many people asking about the importance of plant community diversity in bolstering productivity, resistance to pest and pathogen pressure and wildlife habitat, among other ecosystem services. We review the current understanding of diversity–productivity relationships across multiple spatial scales, but also emphasize perspectives that have received less attention in the literature.

Associations among Selection Logging History, Brook Trout, Macroinvertebrates, and Habitat in Northern Michigan Headwater Streams

Abstract Selection logging is a dominant forest management technique in mixed-hardwood forests of the Laurentian Great Lakes region, yet little is known about its potential effects on neighboring streams and their communities. We surveyed nine headwater streams of the Otter River watershed in Michigans Upper Peninsula for which the adjacent forest had undergone selection logging in the previous 2 to 30 years to examine whether the abundance of brook trout Salvelinus fontinalis was related to the logging history, stream habitat conditions, or aquatic macroinvertebrate composition. Mean abundances of age-1 and older brook trout were estimated by electrofishing replicate 100-m sections of each stream in 1999 and 2000. Aquatic macroinvertebrates were surveyed in 1999, and stream habitat was surveyed in 2000. Correlation models showed that brook trout density and biomass were substantially lower in streams bordering more recently logged forests. Brook trout abundance was also positively correlated with the re...

Relationship between Carnivore Distribution and Landscape Features in the Northern Highlands Ecological Landscape of Wisconsin

Abstract Residential development has been associated with habitat fragmentation and loss and declining diversity of indigenous species, especially when development occurs in ecologically sensitive environments such as wetlands and/or riparian zones. In recent decades, the upper mid-west region of the United States has experienced a dramatic increase in residential development along lakeshores. In northern Wisconsin, recent studies have documented negative effects of such development on local flora and certain fauna (avian and amphibian communities) but less is known about how mammal communities, especially carnivores, respond to housing development. To quantify the influence of lakeshore development on these taxa, we conducted snow track surveys on 10 pairs of low- and high-development lakes and deployed remote cameras at four lakes in Vilas County, Wisconsin, in 2008. Our results suggest that a higher diversity of carnivores (P  =  0.006) were present on low-development lakes. Coyotes (Canis latrans) wer...

Forest reserves and riparian corridors help maintain orchid bee (Hymenoptera: Euglossini) communities in oil palm plantations in Brazil

Orchid bees (Apidae, Euglossini) are important pollinators in the Amazon forest. In eastern Brazilian Amazon, secondary forest and pastures are being replaced by oil palm plantations. Here, we tested the role of forest reserves and riparian corridors in maintaining orchid bees. We sampled bees in three different soil-type uses, comparing richness, abundance, and assemblage composition. Estimated richness was lowest in palm plantations than in forest reserves and riparian corridors on diversity of orchid bees. Riparian corridors had the highest abundance, followed by reserves, and oil palm plantations. Bee assemblage also varied with land cover, with the reserves having the most distinct composition. We also identified indicator bees for primary forest. Our results demonstrate riparian corridors and forest reserves can maintain orchid bees in oil palm landscapes.

Influence of plant community composition on biomass production in planted grasslands.

United States energy policy mandates increased use of renewable fuels. Restoring grasslands could contribute to a portion of this requirement through biomass harvest for bioenergy use. We investigated which plant community characteristics are associated with differences in biomass yield from a range of realistic native prairie plantings (n = 11; i.e., conservation planting, restoration, and wildlife cover). Our primary goal was to understand whether patterns in plant community composition and the Floristic Quality Index (FQI) were related to productivity as evidenced by dormant season biomass yield. FQI is an objective measure of how closely a plant community represents that of a pre-European settlement community. Our research was conducted in planted fields of native tallgrass prairie species, and provided a gradient in floristic quality index, species richness, species diversity, and species evenness in south-central Wisconsin during 2008 and 2009. We used a network of 15 randomly located 1 m2 plots within each field to characterize the plant community and estimate biomass yield by clipping the plots at the end of each growing season. While plant community composition and diversity varied significantly by planting type, biomass yield did not vary significantly among planting types (ANOVA; P >0.05). Biomass yield was positively correlated with plant community evenness, richness, C4 grass cover, and floristic quality index, but negatively correlated with plant species diversity in our multi-season multiple linear mixed effects models. Concordantly, plots with biomass yield in the lowest quartile (biomass yield < 3500 kh/ha) had 8% lower plant community evenness and 9% lower FQI scores than those in the upper quartile (biomass yield > 5800 kh/ha). Our results suggest that promoting the establishment of fields with high species evenness and floristic quality may increase biomass yield, while simultaneously supporting biodiversity.

SCALE-DEPENDENT RESPONSE BY BREEDING SONGBIRDS TO RESIDENTIAL DEVELOPMENT ALONG LAKE SUPERIOR

Abstract We examined the influence of shoreline residential development on breeding bird communities along forested portions of Lake Superior and hypothesized that anthropogenic changes related to housing development would alter bird community structure compared to areas without human development. We used point counts to compare relative abundance of bird species in relation to residential development at coarse (along 1 km shoreline stretches with and without housing/cottage development) and fine (developed and undeveloped sides of a shoreline access road) spatial scales during the 2005 breeding season. More species had development related differences in abundance at the finer-scale analysis than at the coarse scale. American Crows (Corvus brachyrhynchos) and American Robins (Turdus migratorius) were more abundant on the developed, shoreline side of shoreline access roads. Red-breasted Nuthatches (Sitta canadensis), Black-throated Green Warblers (Dendroica virens), and Red-eyed Vireos (Vireo olivaceus) were more abundant on the undeveloped, inland side of shoreline access roads. Several species were detected exclusively in developed or undeveloped forest areas. The pattern of development-related differences in relative abundance of bird species depended on the scale at which data were analyzed, suggesting that many species may respond to habitat differences within the 100 m scale quite distinct from how they respond to differences at the scale of thousands of meters.

Bird community responses to afforested eucalyptus plantations in the Argentine pampas

Land-use change driven by human population growth and economic activity will continue to impact both natural habitats and land currently being used for food, fiber, and fuel production. The effects of this conversion on economically important ecological services will in large part depend on how native biodiversity responds to these changes. We investigated how agriculture-related land use change influences the avian community in northeastern Argentina by examining common agricultural land uses (pasture/annual crops, young and mature large-scale eucalyptus plantations, mixed-use farms with citrus, blueberry and small stands of eucalyptus) and remnant native espinal savannas. In this region, afforested eucalyptus plantations represent a new land-use change from the land cover of pasture with intermixed annual crops that has dominated the region. In this mosaic, we used point counts to assess how avian diversity and community structure differed between land uses. Bird species richness was lowest in older plantations and highest in the espinal savanna, with the other land uses having intermediate richness. Abundance trends followed the same pattern, with low overall abundance in the plantations, intermediate levels for pasture/annual crops, and highest abundance in the espinal. Distinct bird community assemblages were strongly associated with each land use, and between young and mature eucalyptus stands. Birds can be useful indicators for biodiversity as a whole, and the depopulated and depauperate avian community within the eucalyptus plantations will likely lead to reduced provision of many ecosystem services in this region if the spatial extent of plantations continues to expand.

Avian Community Response to Short-rotation Aspen Forest Management

Abstract In the upper midwestern US and parts of Canada, forests dominated by Populus tremuloides (Aspen) are increasingly being considered as a bioenergy feedstock for power plants. When used for bioenergy, these forests are harvested at much younger ages than when they are used for more traditional products, such as pulpwood and lumber. To better understand the potential consequences of a shift in shorter-rotation-harvest strategies on avian communities, we employed point counts to examine bird community composition in a chronosequence (10-45 y since harvest) of 12 coppiced, even-aged Aspen stands. Young (8-15 y old), middle (20-44 y old), and mature (45 y old) stands had no significant differences in species richness or relative abundance, but distinct avian community assemblages were associated with each stand-age class. Four bird species were significantly associated with a particular age class. Maintaining a wide range of Aspen stand-age classes in the landscape appears to be the best strategy for conserving a diverse bird community in this region.