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K.F. Higgins

Publications and source records attributed to K.F. Higgins.

At least 19 recordsLinked to original sources
USGS2006

Reticulate melanism in western painted turtles (Chrysemys picta bellii): Exploring linkages with habitat and heating rates

In western painted turtles (Chrysemys picta bellii), males often exhibit one of two morphs: (1) a reticulated form, characterized by an intricate network of dark markings on the carapace or (2) a non-reticulated form. Although several hypotheses have been proposed to explain the adaptive significance of reticulate melanism (RM) on western painted turtles, no attempts have been made to document whether RM is linked to habitat conditions or if the presence of melanism affects heating rates. To evaluate these questions, we compared the frequency of adult male turtles with RM across three different habitats: riverine (rivers), lacustrine (lakes) and palustrine (wetland) habitats. Using manipulative experiments, we also tested the hypothesis that body heating rates are higher in turtles with RM. Reticulate melanism occurred on 99 (31%) of 320 male turtles captured in South Dakota from 2002 to 2003. Turtles with reticulate melanism were significantly larger than non-reticulated turtles; RM was not observed on male turtles with carapace lengths <15 cm or weights <360 g. The mean proportion of adult male turtles (>15 cm carapace length) with RM was similar among river (0.54), lake (0.50) and wetland (0.64) habitats, implying that RM is not a habitat-linked trait. Heating rates for turtles with RM were similar to those measured for non-reticulated individuals. Body size, however, influenced heating rates; larger-bodied turtles with lower surface area-to-volume ratio heated more slowly than smaller turtles. Whether RM is a by-product of hormonal regulation or serves an adaptive purpose remains unclear. However, other hypotheses, especially those involving communication (e.g., courtship behavior) and/or gamete protection remain untested for western painted turtles and warrant further investigation.

American Midland Naturalist↗
USGS2003

Effects of CRP field age and cover type on ring-necked pheasants in eastern South Dakota

Loss of native grasslands to tillage has increased the importance of Conservation Reserve Program (CRP) grasslands to maintain ring-necked pheasant (Phasianus colchicus) populations. Despite the importance of CRP to pheasants, little is known about the effects of CRP field age and cover type on pheasant abundance and productivity in the northern Great Plains. Therefore, we assessed effects of these characteristics on pheasant use of CRP fields. We stratified CRP grasslands (n=42) by CRP stand age (old [10-13 yrs] vs. new [1-3 yrs] grasslands) and cover type (CP1 [cool-season grasslands] vs. CP2 [warm-season grasslands]) in eastern South Dakota and used crowing counts and roadside brood counts to index ring-necked pheasant abundance and productivity. Field-age and cover-type effects on pheasant abundance and productivity were largely the result of differences in vegetation structure among fields. More crowing pheasants were recorded in old cool-season CRP fields than any other age or cover type, and more broods were recorded in cool- than warm-season CRP fields. Extending existing CRP contracts another 5-10 years would provide the time necessary for new fields to acquire the vegetative structure used most by pheasants without a gap in habitat availability. Cool-season grass-legume mixtures (CP1) that support higher pheasant productivity should be given equal or higher ratings than warm-season (CP2) grass stands. We also recommend that United States Department of Agriculture administrators and field staff provide broader and more flexible guidelines on what seed mixtures can be used in CRP grassland plantings in the northern Great Plains. This would allow landowners and natural resource professionals who manage pheasant habitat to plant a mosaic of cool- and warm-season CRP grassland habitats.

Wildlife Society Bulletin↗
USGS2000

Bird mortality associated with wind turbines at the Buffalo Ridge wind resource area, Minnesota

Recent technological advances have made wind power a viable source of alternative energy production and the number of windplant facilities has increased in the United States. Construction was completed on a 73 turbine, 25 megawatt windplant on Buffalo Ridge near Lake Benton, Minnesota in Spring 1994. The number of birds killed at existing windplants in California caused concern about the potential impacts of the Buffalo Ridge facility on the avian community. From April 1994 through Dec. 1995 we searched the Buffalo Ridge windplant site for dead birds. Additionally, we evaluated search efficiency, predator scavenging rates and rate of carcass decomposition. During 20 mo of monitoring we found 12 dead birds. Collisions with wind turbines were suspected for 8 of the 12 birds. During observer efficiency trials searchers found 78.8% of carcasses. Scavengers removed 39.5% of carcasses during scavenging trials. All carcasses remained recognizable during 7 d decomposition trials. After correction for biases we estimated that approximately 36 ?? 12 birds (<1 dead bird per turbine) were killed at the Buffalo Ridge windplant in 1 y. Although windplants do not appear to be more detrimental to birds than other man-made structures, proper facility sitting is an important first consideration in order to avoid unnecessary fatalities.

Minnesota↗
USGS1999

Scale-dependent habitat use in three species of prairie wetland birds

We evaluated the influence of scale on habitat use for three wetland-obligate bird species with divergent life history characteristics and possible scale-dependent criteria for nesting and foraging in South Dakota, USA. A stratified, two-stage cluster sample was used to randomly select survey wetlands within strata defined by region, wetland density, and wetland surface area. We used 18-m (0.1 ha) fixed radius circular-plots to survey birds in 412 semipermanent wetlands during the summers of 1995 and 1996. Variation in habitat use by pied-billed grebes (Podilymbus podiceps) and yellow-headed blackbirds (Xanthocephalus xanthocephalus), two sedentary species that rarely exploit resources outside the vicinity of nest wetlands, was explained solely by within-patch variation. Yellow-headed blackbirds were a cosmopolitan species that commonly nested in small wetlands, whereas pied-billed grebes were an area-sensitive species that used larger wetlands regardless of landscape pattern. Area requirements for black terns (Chlidonias niger), a vagile species that typically forages up to 4 km away from the nest wetland, fluctuated in response to landscape structure. Black tern area requirements were small (6.5 ha) in heterogeneous landscapes compared to those in homogeneous landscapes (15.4-32.6 ha). Low wetland density landscapes composed of small wetlands, where few nesting wetlands occurred and potential food sources were spread over large distances, were not widely used by black terns. Landscape-level measurements related to black tern occurrence extended past relationships between wetlands into the surrounding matrix. Black terns were more likely to occur in landscapes where grasslands had not been tilled for agricultural production. Our findings represent empirical evidence that characteristics of entire landscapes, rather than individual patches, must be quantified to assess habitat suitability for wide-ranging species that use resources over large areas.

Landscape Ecology↗
USGS1999

A comparison of sampling techniques to estimate number of wetlands

Service use annual estimates of the number of ponded wetlands to estimate duck production and establish duck hunting regulations. Sampling techniques that minimize bias may provide more reliable estimates of annual duck production. Using a wetland geographic information system (GIS), we estimated number of wetlands using standard counting protocol with belt transects and samples of square plots. Estimates were compared to the known number of wetlands in the GIS to determine bias. Bias in transect-derived estimates ranged from +67-87% of the known number of wetlands, compared to bias of +3-6% in estimates from samples of 10.24-km2 plots. We recommend using samples of 10.24-km2 plots stratified by wetland density to decrease bias.

Wildlife Society Bulletin↗
USGS1999

Effects of wind turbines on upland nesting birds in Conservation Reserve Program grasslands

Grassland passerines were surveyed during summer 1995 on the Buffalo Ridge Wind Resource Area in southwestern Minnesota to determine the relative influence of wind turbines on overall densities of upland nesting birds in Conservation Reserve Program (CRP) grasslands. Birds were surveyed along 40 m fixed width transects that were placed along wind turbine strings within three CRP fields and in three CRP fields without turbines. Conservation Reserve Program grasslands without turbines and areas located 180 m from turbines supported higher densities (261.0-312.5 males/100 ha) of grassland birds than areas within 80 m of turbines (58.2-128.0 males/100 ha). Human disturbance, turbine noise, and physical movements of turbines during operation may have disturbed nesting birds. We recommend that wind turbines be placed within cropland habitats that support lower densities of grassland passerines than those found in CRP grasslands.

The Wilson Bulletin↗
USGS1997

Factors influencing wetland use by Canada geese

Seasonal and semi-permanent wetlands in eastern South Dakota were surveyed in 1995 and 1996 to identify habitat characteristics influencing wetland use by Canada geese ( Branta canadensis maxima ). Position of a wetland within the landscape and its area were important landscape-scale features influencing wetland use by geese. Our delineation of potential Canada goose habitat using a wetland geographic information system indicated that distribution and area of semi-permanent wetlands likely limit Canada goose occurrence in regions outside the Prairie Coteau. Periodicity in hydrologic cycles within landscapes also may influence goose use of wetlands in eastern South Dakota.

South Dakota↗
USGS1992

Waterfowl production on the Woodworth Station in south-central North Dakota, 1965-1981

During 17 years of study at the Woodworth, North Dakota study area, the percent of 548 wetland basin with water during 1-15 May ranged from 8 to 87 and averaged 56; waterfowl pair densities varied from 19 to 56/km2 and averaged 40/km2. Pond occupancy by duck pairs averaged 37% during mid-May counts and 48% for late May and early June counts. A positive linear relation occurred between the estimated number of duck pairs and the percent of basins with water during 1-15 May.There were 3,339 duck nests found in grassland habitats from 1966 through 1981. Approximately 66% (85% Mayfield) of these were depredated or abandoned. Mammals caused 88% of nest failures. Half or more of the eventually successful clutches were unhatched by 10 July in 9 of 16 years. Haying would have disturbed or destroyed an average of 43%, 33%, 22%, 15%, and 9% of the duck nests if initiated on 10 July, 15 July, 20 July, 25 July, and 1 August, respectively.The total average size of completed clutch for all species was 29% smaller at the end of the nesting season than at the beginning, underscoring the importance of protecting early clutches.Production averaged 30 broods per 100 pairs of ducks and ranged from 15 to 61 broods per 100 pairs. Brood densities ranged from 10 to 63/km2 and averaged 12/km2. Mean brood size averaged 6.4 for all species. July broods averaged 7.2 ducklings and August broods 5.7 ducklings. Duckling loss averaged 2.6 per brood and 85% (2.2 ducklings) of this loss was estimated to occur during the first 14 days after hatch.Wetlands of all sizes and classes were important at some time to one species of duck or another. With the exception of some diving ducks, all species used a complex of sizes and classes of wetlands for space, food, and shelter necessary for nesting and brooding. Pair counts during 20 May-7 June were most indicative of the breeding population. A combination of two brood counts resulted in the best estimate of annual production. An average of only 50% of the total duck broods per year was counted during the 1-15 July surveys, which approximated the average time of the Service's July aerial surveys. During this study the area produced an average of 1 duck per 4 ha of upland and had a nest density of approximately 1 nest per 14 ha. Nest success rates averaged 35.1% (16.3% Mayfield). Predation was significantly reduced by good vegetative cover at nest sites. Seeded grasslands (dense nesting cover) yielded better production than native prairie or croplands. Seeded grasslands also produced 3 times more ducklings per unit area than adjacent native prairie and more than 14 times as many as adjacent, annually tilled croplands.Ducks generally showed higher nest densities and better nesting success when using growing grain crops than when nesting in standing or mulched stubble fields. Among native mixed-grass prairie and seeded grassland, production was enhanced by leaving fields idle or by treating them with periodic burning. Duck production was generally lowered by grazing field of native prairie but duck production on grazing lands was higher than in annually tilled croplands.

Resource Publication↗
USGS1986

Comparison of wetland drainage during and after protection by 20-year easements

We determined drainage rates for wetlands in North and South Dakota with U.S. Fish and Wildlife Service 20-year easements, during (1961-1980) and after (1981-1984) contract protection. Average annual drainage rates were 10 times higher during the four postcontract years than during the 20 contract years on the same tracts of land. Twenty-year easements only delayed wetland drainage, and are of limited value for securing a long-term habitat base.

Prairie Naturalist↗
USGS1986

Effects of shrub coverages on birds of North Dakota mixed-grass prairies

We studied the distribution and density of passerine birds in relation to Wolfberry (Symphoricarpos occidentalis) and Silverberry (Elaeagnus commutata) shrub coverages on mixed-grass prairies of central North Dakota. Birds were counted along shrubby and shrubless transects during the 1982 breeding season. Species richness and total density of birds were greater on shrubby transects. Five species were more abundant on shrubby transects. Availability of woody nesting substrates best explained differences in bird species abundances. Differences in shrub coverages between transects were probably the result of different land-use practices. Land management practices which modify shrub coverages can alter the composition of passerine bird communities.

North Dakota↗
USGS1984

Lightning fires in North Dakota grasslands and in pine-savanna lands of South Dakota and Montana

Lightning strike fires which occurred between 1940 and 1981 were studied in mixed-grass prairie grasslands and in pine-savanna lands in the Northern Great Plains region. A majority (73%) of ignitions occurred during July and August, while a lesser number was recorded in April, May, June, and September. The April-September period is also the average time of the freeze-free period and approximates the average distribution period for thunderstorm activity in this region. The area burned by each of 293 lightning fires (most of which were suppressed) ranged from 0.004-1158.3 ha ( X̄ = 10.8 ha). The frequency of lightning fires in mixed-grass prairie grasslands averaged 6.0/yr per 10,000 km 2 in eastern North Dakota, 22.4/yr per 10,000 km 2 in southcentral North Dakota, 24.7/yr per 10,000 km 2 in western North Dakota, and 91.7/yr per 10,000 km 2 in pine-savanna lands in northwestern South Dakota and southeastern Montana. The ecological role of lightning-set fires is discussed relative to the development of resource research and management plans and to the interpretation of historical records of natural fire occurrence in the Northern Great Plains region.

Journal of Range Management↗
USGS1984

Breeding bird community colonization of sown stands of native grasses in North Dakota

Breeding passerine birds were studied in three native grass plantings of predominantly western wheatgrass (Agropyron smithii) and green needlegrass (Stipa viridula) in south-central North Dakota during 1982-1984. A total of eight different species of passerines readily colonized this relatively new type of wildlife habitat during the second, third. and fourth growing seasons.

Prairie Naturalist↗
USGS1983

Environmental factors that influence prescribed burning in the Northern Plains

Several environmental conditions were recorded and analyzed for 192 prescribed burns in the Northern Great Plains. The purpose of these burns was to improve wildlife habitat and manipulate native prairie vegetation. All of the fires occurred in grassland and shrubsteppe vegetation types. Fuels were predominantly grasses and forbs intermixed with patches of shrubs. Nearly all of the fuels were <1.5 m tall. Shrub stems averaged <2.5 cm in diameter.In northern grasslands, prescribed burns can be conducted successfully during all months when there is no snow or ice cover on the ground. However, the burns analyzed here were conducted between March and October during all hours of the day or night.Burns were conducted under a wide range of environmental conditions. For example, one plot of mixed-grass prairie burned successfully just 9 hours after it received 1.2 cm of rain; another plot of mixed-grass prairie burned successfully when ambient air temperature was only 1.7 deg.C. Heavy fuels will often burn for short periods of time though light rain or snow are falling.Precipitation, relative humidity, temperature, cloud cover, and wind speed and direction are important climatic factors to consider before and during prescribed burns. These factors influence ignition of fuels, fire behavior, and fire effects. The 4 basic environmental conditions that influence the burning of northern plains grasslands and shrubsteppe are those that:1) Prohibit ignition or spread of fires. Plots with complete snow or ice cover, or those ignited during rainfall rates >0.05 cm/h, do not burn. However, these are good conditions to burn stockpiles of unwanted fuels that are usually high risk elements during regular prescribed burns.2) Produce partial burns. Partial burns are defined as those where fire is discontinuous and patches of standing and lodged vegetation are left unburned. Partial burns occur most often when fine fuels feel moist when handled, where less than 2 days have passed since the last measurable precipitation, and when cloud cover is complete. Other conditions associated with partial burns are relative humidities >50 percent, temperatures <21 deg.C, and wind speeds <10 km/h. These conditions occur most often during May and June.3) Produce complete burns. Complete burns are defined as those in which fire is continuous and nearly all vegetation (standing, lodged, and ground litter) is consumed by the fire. Complete burns occur most often when fine fuels feel dry when handled, 2 or more days have passed since the last measurable precipitation, and the sky is partly cloudy to clear. Complete burns occur with relative humidities between 25 and 50 percent, temperatures between 21 and 32 deg.C, and wind speeds of 13 to 24 km/h. These conditions occur most often in July, August, and September, but can occur anytime from March through November.4) Produce high risk fires. High risk fires are defined as those fires that are conducted during undesirable climatic conditions. High risk fires can always be expected with a combination of high winds, low humidity, high temperatures, and no recent precipitation. These conditions are most probable with wind speeds >32 km/h, relative humidities <20 percent, and temperatures >35 deg.C. These conditions occur most often in July, August, and September, but can occur anytime from April through October.

Book chapter↗