Geology topics

Louis B. Best

Publications and source records attributed to Louis B. Best.

6 recordsLinked to original sources

USGS2003

Potential effects on grassland birds of converting marginal cropland to switchgrass biomass production

Habitat loss is a major reason for the decline of grassland birds in North America. Five habitats (pastures, hayfields, rowcrop fields, small-grain fields, Conservation Reserve Program fields) compose most of the habitat used by grassland birds in the Midwest United States. Growing and harvesting switchgrass (Panicum virgatum) as a biomass fuel would create another habitat for grassland birds. Bird abundance information from studies conducted in Iowa and adjacent states and land-use data for the Rathbun Lake Watershed in southern Iowa were used in a Geographic Information System to model the potential effects on bird abundances of converting rowcrop fields to biomass production. Abundances of bird species that are management priorities increased in both biomass scenarios. Common yellowthroat (Geothlypis trichas) abundance in the watershed also increased greatly in both scenarios. Other species (e.g., homed lark [Eremophila alpestris], killdeer [Charadrius vociferous]) were more abundant in the existing land use than in the biomass scenarios, and conversion of fields from rowcrop to biomass production could be detrimental to these species. In general, biomass fields will provide habitat for grassland birds that are management priorities, but future monitoring of birds in such fields is needed as conversion of rowcrop fields to biomass production continues. ?? 2002 Elsevier Science Ltd. All rights reserved.

Biomass and Bioenergy↗

USGS2003

Short-term bird response to harvesting switchgrass for biomass in Iowa

The Conservation Reserve Program (CRP) provides habitat for grassland birds, but as contracts expire, some CRP fields might be returned to rowcrop production. One alternative to returning CRP fields to rowcrops is to produce switchgrass ( Panicum virgatum ) for use as a biomass fuel. Because the biomass is harvested during the fall and winter, breeding birds would not be directly affected by mowing the fields bur might be influenced by changes in vegetation structure resulting from the harvest. We evaluated bird abundances and nest success in totally harvested, partially harvested (alternating cut and uncut strips), and nonharvested CRP switchgrass fields in southern Iowa, USA, in 1999 and 2000. Species richness did not differ among harvest treatments. Abundances of most species (16 of 18) were not affected by the harvesting of switchgrass fields, and strip width did not affect bird numbers in strip-harvested fields. Grasshopper sparrows ( Ammodramus savannarum ) were more abundant in harvested portions of fields, and more sedge wrens ( Cistothorus platensis ) were recorded in nonharvested areas. The residual vegetation in nonharvested areas provided nest cover for species that begin nesting early in the season (e.g., northern harrier [Circus cyaneus] and ring-necked pheasant [ Phasianus colchicus ]). Nest success rates of grasshopper sparrows and common yellowthroats ( Geothlypis trichas ) were similar to those reported by other studies in switchgrass fields and might be sufficient to maintain stable populations. In general, switchgrass biomass fields create breeding habitat for some grassland birds, and a mixture of harvested and nonharvested fields would be more beneficial to grassland birds than totally harvesting or partially harvesting all switchgrass fields.

Iowa↗

USGS2001

On the rarity of observations of food provisioning by male dickcissels

Males of polygynous bird species typically provide less parental care to their offspring than males of monogamous species (Ketterson and Nolan 1994). Generally, in polygynous species, a male forfeits some potential reproductive success if he shifts his reproductive effort from mating with multiple females to parental care (Trivers 1972, Gubemick et al. 1993, Schleicher et al. 1993). In the polygynous dickcissel ( Spiza americana ), singing and foraging activities constitute much of a male's time-activity budget (Schartz and Zimmerman 1971, Finck 1984). Although male dickcissels are attentive to their nests and mates (e.g., nest protection and vigilance) females incubate the eggs and feed the young (Gross 1921). Herein, we describe an account of a male dickcissel feeding brown-headed cowbird ( Molothrus ater ) young early in the breeding season, summarize and review previous reports of food provisioning by the male dickcissel, and discuss the rarity of this behavior in the dickcissel.

Prairie Naturalist↗

USGS2000

Comparisons of methods for determining dominance rank in male and female prairie voles ( Microtus ochrogastor )

Dominance ranks in male and female prairie voles ( Microtus ochrogaster ) were determined from 6 measurements that mimicked environmental situations that might be encountered by prairie voles in communal groups, including agonistic interactions resulting from competition for food and water and encounters in burrows. Male and female groups of 6 individuals each were tested against one another in pairwise encounters (i.e., dyads) for 5 of the measurements and together as a group in a 6th measurement. Two types of response variables, aggressive behaviors and possession time of a limiting resource, were collected during trials, and those data were used to determine cardinal ranks and principal component ranks for all animals within each group. Cardinal ranks and principal component ranks seldom yielded similar rankings for each animal across measurements. However, dominance measurements that were conducted in similar environmental contexts, regardless of the response variable recorded, ranked animals similarly. Our results suggest that individual dominance measurements assessed situation- or resource-specific responses. Our study demonstrates problems inherent in determining dominance rankings of individuals within groups, including choosing measurements, response variables, and statistical techniques. Researchers should avoid using a single measurement to represent social dominance until they have first demonstrated that a dominance relationship between 2 individuals has been learned (i.e., subsequent interactions show a reduced response rather than an escalation), that this relationship is relatively constant through time, and that the relationship is not context dependent. Such assessments of dominance status between all dyads then can be used to generate dominance rankings within social groups.

Journal of Mammalogy↗

USGS2000

A comprehensive review of Farm Bill contributions to wildlife conservation, 1985-2000

A comprehensive review of the scientific literature was undertaken to determine wildlife responses to programs established under the conservation title of the 1985 Food Security Act as amended in 1990 and 1996 (Farm Bill). Literature was annotated and summaries of wildlife responses were provided for the Conservation Reserve Program CRP, Wetlands Reserve Program (WRP), Wildlife Habitat Incentives Program (WHIP) and Environmental Quality Incentives Program (EQIP). The report recognized that Farm Bill conservation programs were created to serve many purposes. Foremost among these purposes was to enable Americaa??s farmers and ranchers to be better stewards of their lands. In general, wildlife responded positively to improvements in land stewardship, particularly when the needs of wildlife were considered in conservation planning and implementation. Whereas authors acknowledged that their understanding of wildlife responses to Farm Bill conservation programs was still incomplete, they concluded that these programs were making significant contributions toward conservation of the nationa??s fish and wildlife resources.

Technical Report↗

USGS1981

Effects of habitat alterations on riparian plant and animal communities in Iowa

A large proportion of the streams in the Midwest have been channelized to facilitate wetlands drainage, reduce flooding, and encourage various floodplain development activities. Changes that result from stream channelization impact hydrological and ecological processes that in turn affect fish and wildlife populations. This study was conducted to better describe the changes that occur in riparian ecosystems located adjacent to selected Iowa streams.

FWS/OBS↗