Native Prairie Habitats Research Articles

Long-term trends in grassland bird relative abundance on focal grassland landscapes in Missouri.

North American grassland birds have widely declined over the past 50 years, largely due to anthropogenic-driven loss of native prairie habitat. In response to these declines, many conservation programs have been implemented to help secure wildlife habitat on private and public lands. The Grasslands Coalition is one such initiative established to advance the conservation of grassland birds in Missouri. The Missouri Department of Conservation conducted annual point count surveys for comparison of grassland bird relative abundance between focal grassland areas and nearby paired (i.e., containing no targeted management) sites. We analyzed 17 years of point count data with a generalized linear mixed model in a Bayesian framework to estimate relative abundance and trends across focal or paired sites for nine bird species of management interest that rely on grasslands: barn swallow (Hirundo rustica), brown-headed cowbird (Molothrus ater), dickcissel (Spiza americana), eastern meadowlark (Sturnella magna), grasshopper sparrow (Ammodramus savannarum), Henslow's sparrow (A. henslowii), horned lark (Eremophila alpestris), northern bobwhite (Colinus virginianus), and red-winged blackbird (Agelaius phoeniceus). Relative abundance of all species except eastern meadowlarks declined regionally. Relative abundance of barn swallows, brown-headed cowbirds, dickcissels, eastern meadowlarks, Henslow's sparrows, and northern bobwhites was higher in focal than paired sites, though relative abundance trends were only improved in focal vs. paired areas for dickcissels and Henslow's sparrows. Relative abundance increased with increasing grassland cover at the local (250-m radius) scale for all species except horned larks and red-winged blackbirds and at the landscape (2,500-m radius) scale for all species except dickcissels, eastern meadowlarks, and northern bobwhites. Our results suggest focal areas contained greater relative abundances of several grassland species of concern, likely due to increased availability of grassland habitat at local and landscape scales. Further efforts to decrease landscape-scale fragmentation and improve habitat quality may be needed to achieve conservation goals.

Access to prairie pollen affects honey bee queen fecundity in the field and lab

Beekeepers experience high annual losses of colonies, with environmental stressors like pathogens, reduced forage, and pesticides as contributors. Some factors, like nutritional stress from reduced flower abundance or diversity, are more pronounced in agricultural landscapes where extensive farming limits pollen availability. In addition to affecting other aspects of colony health, quantity and quality of pollen available are important for colony brood production and likely for queen egg laying. While some US beekeepers report >50% of colony loss due to queen failure, the causes of poor-quality queens are poorly understood. Access to resources from native prairie habitat is suggested as a valuable late-season resource for honey bees that can reverse colony growth declines, but it is not clear how prairie forage influences queen egg laying. We hypothesized that the pollen resources present in an extensive Midwestern corn/soybean agroecosystem during the critical late season period affect honey bee queen egg laying and that access to native prairies can increase queen productivity. To test this, we designed a field experiment in Iowa, keeping colonies in either soybean or prairie landscapes during a critical period of forage dearth, and we quantified queen egg laying as well as pollen collection (quantity and species). Then, using pollen collected in the field experiments, we created representative dietary mixtures, which we fed to bees using highly controlled laboratory cages to test how consumption of these diets affected the egg laying of naive queens. In two out of three years, queens in prairies laid more eggs compared to those in soybean fields. Pollen quantity did not vary between the two landscapes, but composition of species did, and was primarily driven by collection of evening primrose (Oenothera biennis). When pollen representative of the two landscapes was fed to caged bees in the laboratory queens fed prairie pollen laid more eggs, suggesting that pollen from this landscape plays an important role in queen productivity. More work is needed to tease apart the drivers of these differences, but understanding how egg laying is regulated is useful for designing landscapes for sustainable pollinator management and can inform feeding regimes for beekeepers.

Do honey bee (Apis mellifera) foragers recruit their nestmates to native forbs in reconstructed prairie habitats?

Honey bee (Apis mellifera) colonies are valued for the pollination services that they provide. However, colony mortality has increased to unsustainable levels in some countries, including the United States. Landscape conversion to monocrop agriculture likely plays a role in this increased mortality by decreasing the food sources available to honey bees. Many land owners and organizations in the Upper Midwest region of the United States would like to restore/reconstruct native prairie habitats. With increasing public awareness of high bee mortality, many landowners and beekeepers have wondered whether these restored prairies could significantly improve honey bee colony nutrition. Conveniently, honey bees have a unique communication signal called a waggle dance, which indicates the locations of the flower patches that foragers perceive as highly profitable food sources. We used these communication signals to answer two main questions: First, is there any part of the season in which the foraging force of a honey bee colony will devote a large proportion of its recruitment efforts (waggle dances) to flower patches within prairies? Second, will honey bee foragers advertise specific taxa of native prairie flowers as profitable pollen sources? We decoded 1528 waggle dances in colonies located near two large, reconstructed prairies. We also collected pollen loads from a subset of waggle-dancing bees, which we then analyzed to determine the flower taxon advertised. Most dances advertised flower patches outside of reconstructed prairies, but the proportion of dances advertising nectar sources within prairies increased significantly in the late summer/fall at one site. Honey bees advertised seven native prairie taxa as profitable pollen sources, although the three most commonly advertised pollen taxa were non-native. Our results suggest that including certain native prairie flower taxa in reconstructed prairies may increase the chances that colonies will use those prairies as major food sources during the period of greatest colony growth and honey production.

Development of Techniques to Improve Coastal Prairie Restoration on the Clatsop Plains, Oregon

With the substantial losses of native prairie habitat over the last century, research focusing on the restoration of prairies has become imperative in order to conserve these imperiled ecosystems and the biodiversity they support. On the Clatsop Plains in northwestern Oregon, there are only a few remnant patches of coastal prairie, which are vital for many species including the federally threatened Oregon silverspot butterfly (Speyeria zerene hippolyta). Building upon previous work done on the Clatsop Plains, we implemented a study to develop techniques to improve coastal prairie restoration in this region. The objective of this study was to identify an effective site preparation/treatment that resulted in the greatest success of seeded forb and graminoid establishment, while also limiting introduced graminoid and forb species. We examined the effectiveness of four treatments (untreated control, herbicide, soil inversion, and soil removal) at three sites on the Clatsop Plains. After three seasons, the soil removal treatment enhanced native species abundance while maintaining low cover of introduced forbs and graminoids. However, cost of these methods is also an important consideration for land managers. Soil removal was the most effective treatment we tested, but it would be more expensive to implement on a large scale compared to the other treatments.

Effects of Grass Seed Agriculture on Aquatic Invertebrate Communities Inhabiting Seasonal Wetlands of the Southern Willamette Valley, Oregon

Wetland loss throughout the United States has contributed substantially to landscape fragmentation and loss in biodiversity. In Oregon’s Willamette Valley, only 1 % of native-wet prairie habitat still exists, though seasonal wetlands are still common. These hydrogeomorphic Flats wetlands predominately occur on privately owned and actively farmed lands. We studied these wetlands in spring of 2009 and 2010 in order to quantify and compare aquatic invertebrate communities in two agricultural land-use groups (annual and perennial-grass-seed fields) with native-wet prairie habitat. Community composition in native-prairie, including higher taxa richness and greater diversity, differed from farmed wetlands. Invertebrate densities did not differ among land-uses. However, biomass in perennial-grass wetlands was greater than in annual-grass wetlands both years, and during 2009, it was more than in native-prairie. Lower turbidity, lower conductivity levels, and greater availability of rooted vegetation in native-prairie habitat were conditions associated with differences in invertebrate composition among land-uses. Though invertebrate communities in farmed wetlands differed from native-prairie, the importance of these seasonal wetlands in an altered and fragmented Willamette Valley landscape speaks to their potential contribution for the region’s biodiversity and to their inclusion for management of agricultural lands.

Unknown and unprotected the imperiled genetic resource of native plant populations on roadsides and private lands

Abstract The Willamette Valley has lost almost 99% of its native prairie habitat. The most vulnerable populations of native plants are on roadsides and unprotected private lands. Collection of seed from these populations is therefore imperative, not only to ensure these genetics are not lost but to develop a supply of genetically diverse native plant material for restoration of prairie ecosystems in the Willamette Valley. Although debate continues among restoration professionals as to the appropriateness of mixing seed sources, acceptance is growing in the Valley that this is desirable within an ecoregion. The hope is that diverse, established populations for restoration will have a better chance of survival over the long term.

Butterfly responses to prairie restoration through fire and grazing

The development of land for modern agriculture has resulted in losses of native prairie habitat. The small, isolated patches of prairie habitat that remain are threatened by fire suppression, overgrazing, and invasion by non-native species. We evaluated the effects of three restoration practices (grazing only, burning only, and burning and grazing) on the vegetation characteristics and butterfly communities of remnant prairies. Total butterfly abundance was highest on prairies that were managed with burning and grazing and lowest on those that were only burned. Butterfly species richness did not differ among any of the restoration practices. Butterfly species diversity was highest on sites that were only burned. Responses of individual butterfly species to restoration practices were highly variable. In the best predictive regression model, total butterfly abundance was negatively associated with the percent cover of bare ground and positively associated with the percent cover of forbs. Canonical correspondence analysis revealed that sites with burned only and grazed only practices could be separated based on their butterfly community composition. Butterfly communities in each of the three restoration practices are equally species rich but different practices yield compositionally different butterfly communities. Because of this variation in butterfly species responses to different restoration practices, there is no single practice that will benefit all species or even all species within habitat-specialist or habitat-generalist habitat guilds.

Habitat and Landscape Associations of Breeding Birds in Native and Restored Grasslands

In the midwestern United States, less than 1% of the original tallgrass prairie ecosystem remains. State and federal agencies have responded to this habitat loss with programs and land acquisition that have increased the amount of grassland on the landscape by restoring grassland from other land-use practices. We assessed the effects of habitat restoration and the relative contribution of local habitat and landscape factors on breeding grassland birds in northern Iowa. During the 1999 and 2000 breeding seasons, we surveyed grassland birds in 10 tallgrass prairies and 10 restored grasslands that contained a wide diversity of habitat and landscape conditions. Densities of common bird species were similar between habitat types, except for grasshopper sparrows (Ammodramus savannarum) and savannah sparrows (Passerculus sandwichensis), which were 4 and 9 times more dense in restored grasslands, respectively. Species richness of breeding birds was similar between habitat types. Habitat structure was different in prairies and restored grasslands; restored grasslands had 7% less total vegetation cover and 3% more bare ground. A nested, multiscale analysis indicated that habitat structure explained some variation in species richness and bird density of all common species, yet addition of landscape structure improved models for species richness and for density of 4 of 8 species considered, explaining an additional 10-29% of the variation. Edge-density metrics were the most common variables entering into landscape models; most species had lower densities in landscapes with high edge density. Our results indicate that restored grassland habitats contain bird communities generally similar to those in native prairie habitats in northern Iowa, suggesting that restored grasslands may provide similar habitat suitability for most grassland birds. In addition, both local habitat and landscape factors can be important for managing breeding grassland birds.

Farm Bill Environmental Program May Threaten Native Prairie Habitat

Farm Bill Environmental Program May Threaten Native Prairie Habitat

Breeding Ecology of Greater Prairie-chickens (Tympanuchus cupido) in Relation to Prairie Landscape Configuration

Abstract To better understand the role of prairie landscape configuration on the population dynamics and conservation of greater prairie-chickens, we compared population trends and breeding ecology of prairie-chickens in prairie mosaic and contiguous prairie landscapes in southwestern Missouri. Over 27 yr, the contiguous prairie landscape supported a stable population, whereas the prairie-chicken population in the prairie mosaic landscape declined. In 1986 and 1987, less than one-third of greater prairie-chicken nests occurred in native prairie habitats in the prairie mosaic landscape, but 90% of nests in the contiguous prairie area were in native prairie. Greater prairie-chicken nests established in agricultural habitats had substantially lower nest success than nests in native prairie or mixed native-exotic grass pastures. Nest success was higher in the contiguous prairie landscape than in the prairie mosaic area in 1 of 2 yr. Habitat use by broods differed between the areas: in the contiguous prairie l...

COUNTING DEAD BIRDS: EXAMINATION OF METHODS

We studied three methods (line transect, circular quadrat, complete count) for estimating density of dead birds, using models of sparrows and meadowlarks placed at a density of 50 birds of each type/ha. Line transects with a 500-m search line were used in cultivated pasture and native prairie habitats. The number of birds found by individual searchers in line transects varied markedly, particularly, in pasture habitat. More birds were found, and birds were detected at a greater distance, in prairie than in pasture. More meadowlarks than sparrows were found in both habitats but the mean estimated density of meadowlarks was greater than that of sparrows only in prairie. The number of birds found during most searches was less than that suggested for estimating density accurately and longer search lines were required. Density estimates obtained using circular plots to sample 10% of the prairie area ranged from 20 to 80 birds/ha for meadowlarks and from 10 to 60 birds/ha for sparrows in prairie habitat. A complete search by 25 volunteers spaced at 4 m intervals detected 90% of meadowlarks but only 62% of sparrows in pasture habitat. Mean (SD) time for a single search, including searchers and recorders, was 3.0 (0.8), 1.5 (0.3), and 7.5 person-hours, for line transect, circular plot and complete search, respectively.

A New Prairie Moonwort (Botrychium Subgenus Botrychium) from Northwestern Minnesota

Within the last decade, repeated discoveries of new species of moonworts have shown that the North American diversity of Botrychium subgenus Botrychium has been underappreciated (Wagner & Wagner, 1981, 1983, 1986, 1990a, 1990b). In large measure this is due to the morphological simplicity of these plants and consequent subtlety of morphological differences among species. A further hindrance has been the difficulty of finding these small plants in numbers sufficient for analysis. Recent advances have been achieved through recognition that morphological species differences, though subtle, are detectable and constant, and through heightened awareness of favored moonwort habitats. In western North America the occurrence of moonworts in open grassy mountain meadows and roadsides is well established. It has only recently been discovered that eastern moonworts may also occur abundantly in treeless habitats such as dunes and railroad rights-of-way. It is not surprising, then, that moonworts also occur in native grassland prairies. Botrychium campestre Wagner and Farrar, described from western Iowa prairies (Wagner & Wagner, 1986), in fact has not been recorded from mature woodland habitats. In its reproduction by underground gemmae (Farrar & Johnson-Groh, 1990) and in its early spring phenology, B. campestre appears to be particularly adapted to dry prairie habitats (Farrar, 1985; Farrar & Johnson-Groh, 1986). As part of an ongoing study of the ecology and occurrence of B. campestre in Iowa and Minnesota, we have encountered two other moonworts in native prairie habitats. One of these is the circumboreal Botrychium simplex. Though apparently confined to moist sandy swales in Iowa prairies, B. simplex occurs sporadically throughout many of the prairies we have examined in northwestern Minnesota. The second prairie moonwort encountered in our field research was previously undescribed; here we describe it as a new species.

Distribution, Abundance, and Habitat of the Florida Grasshopper Sparrow

In the early 1900's, the population of Florida grasshopper sparrows (Ammodramus savannarum floridanus) was reportedly large and widespread in Florida; however, surveys between 1980 and 1982 revealed only 93 sparrows at seven sites. The sparrow was found at only one of its former locations, suggesting a reduction in both abundance and occupied range. Although the subspecies prefers stunted oaks (Quercus sp.) and saw palmettos (Serenoa sp.), its ecological requirements seem liberal enough to enable it to persist in some managed cattle pastures. Compared with the habitat of the eastern grasshopper sparrow (A. s. pratensis), habitat used by floridanus has lower values for variables pertaining to vegetation height, vertical density, litter depth, and litter cover, but much higher values for percentage shrub cover and bare ground. Habitat loss or alteration due to pasture management is the greatest threat to the subspecies. A low growth of palmettos and woody shrubs should be maintained in areas where the sparrow occurs. Federal listing of the Florida grasshopper sparrow as threatened or endangered may be appropriate due to its probable low numbers, restricted distribution, and loss of habitat. J. WILDL. MANAGE. 49(3):626-631 The grasshopper sparrow occurs throughout most of temperate North America, but is confined to low to medium height grassland plant communities (Smith 1963). The Florida subspecies is geographically isolated from the eastern race by at least 500 km (Am. Ornithol. Union 1982) and appears to be limited in distribution to the prairie region of south-central Florida. The lack of distributional information precludes a precise delineation of the historical range, and early accounts provide no documented records of abundance. Although specific habitat requirements for floridanus are not known, preliminary investigations suggest they are atypical of the species (Howell 1932, Nicholson 1936). Because of an apparent population decline, the Florida grasshopper sparrow was classified as endangered by the State of Florida (Kale 1978). Much of the native prairie habitat has been converted to improved pasture (Davis 1980), which may have caused the extirpation of the subspecies from some of its former range. Recent observations, however, indicate th' the subspecies may be adapting to some managed pastures (Stevenson 1978). Surveys of the known range of the Florida grasshopper sparrow and potential habitat outside that range were conducted during the breeding season (Apr-Jul) from 1980-82 to gather information on its present distribution and abundance. Vegetation variables were measured at territories of male grasshopper sparrows to provide a quantitative description of habitat for possible use in management of the subspecies. This research was supported by the Fed. Aid to Endangered Species Program, Fla. Endangered Species Proj. E-1. R. L. Barker and S. A. Martin participated in the survey and assisted in locating survey areas. R. P. Wunderlin assisted with plant identification. C. L. Abercrombie provided statistical advice. J. Bart, T. C. Hines, D. S. Maehr, and L. E. Williams, Jr., reviewed earlier drafts of this manuscript and provided many useful suggestions. Special appreciation is extended to A. L. Adams, III, P. Clemons, D. W. Delargey, W. C. Funk, C. E. Lough, and P. T. Wilson, who provided access to their properties. STUDY AREAS AND METHODS Surveys were conducted in the dry prairie region of south-central Florida. Most of this habitat is located within the Kissimmee River Basin and west of Lake Okeechobee in parts of Glades, Hendry, Charlotte and Desoto counties (Davis 1980). In Florida, dry prairie grasslands are extensive treeless plains that often separate freshwater marshes and forested uplands. Seldom flooded, these grasslands are maintained in early successional stages by frequent fires. The vegetation is dominated by pineland threeawn