Geology topics

Melinda G. Knutson

Publications and source records attributed to Melinda G. Knutson.

7 recordsLinked to original sources

USGS2020

Cooperatively improving tallgrass prairie with adaptive management

Adaptive management (AM) is widely recommended as an approach for learning to improve resource management, but successful AM projects remain relatively uncommon, with few documented examples applied by natural resource management agencies. We used AM to make recommendations for the management of native tallgrass prairie plant communities in western Minnesota and eastern North and South Dakota, USA. After nine years of data collection and learning, we report on whether the condition of the prairie improved with management and which actions and frequency of action allowed improvement. Our approach to AM employed Bayesian updating to generate annual management recommendations at a site and state-dependent scale. We also used a logistic regression approach to complement the output from the AM model and evaluate the more general conditions which led to attaining management goals. Overall, the cover of native plants increased for low-quality sites, and among the management practices considered, we found that burning most effectively enhanced the native prairie plant community and increased the dominance of native indicator species. Contrary to expectations, the results also suggest that grazing on sites that started in a poor condition were less likely to show improvements in the native plant community. Complementing AM with more traditional statistical analyses can help inform the iterative doubleloop learning phase of the AM framework. AM has many challenges, but we demonstrate that multi-agency AM can be successful. Keys to success include starting the project with an in-person, in-depth workshop; standardized protocols and a centralized database; a core project team with multi-disciplinary backgrounds; stability in project leadership; and regular communication to meet annual deadlines.

Minnesota, North Dakota, South Dakota↗

USGS2018

Habitat selection, movement patterns, and hazards encountered by northern leopard frogs (Lithobates pipiens) in an agricultural landscape

Telemetry data for 59 Northern Leopard Frogs (Lithobates pipiens) breeding in ponds in Houston and Winona Counties, MN; 2001-2002. Agricultural intensification is causing declines in many wildlife species, including Northern Leopard Frogs (Lithobates pipiens). Specific information about frog movements, habitat selection, and sources of mortality can be used to inform conservation-focused land management and acquisition. We studied Northern Leopard Frogs in southeastern Minnesota, part of the Driftless Area ecoregion, characterized by hills and valleys and a mix of agriculture, forests, small towns and farmsteads. In this area, small farm ponds, originally built to control soil erosion are used by the species for breeding and wintering in addition to riparian wetlands. But, this agricultural landscape may be hazardous for frogs moving between breeding, feeding, and wintering habitats. We surgically implanted transmitters into the peritoneal cavity of 59 Northern Leopard Frogs and tracked them from May to October 2001-2002. The total distance traveled by radio-tagged frogs ranged from 12 to 3316 m, the 95% home range averaged 5.3 ± 1.2 (SE) ha, and the 50% core area averaged 1.05 ± 0.3 (SE) ha. As expected, Northern Leopard Frogs selected wetlands over all other land cover classes and row crops were generally avoided at all levels of selection. Only a few tracked frogs were successful at dispersing (n = 6). Most frogs attempting to disperse (n =31) ended up missing (n = 14), died due to mowing (n = 8), or were recorded as transmitter failure (n = 2) or unknown mortalities (n = 1). For the conservation of Northern Leopard Frogs in this agricultural setting, we must consider both the aquatic and the terrestrial needs of this species. Conservation agencies that restore, manage, and acquire wetlands should consider the hazards posed by land uses adjacent to frog breeding and wintering sites and plan for movement corridors between these locations. For example, grasslands that are mowed or hayed between April and October in the north central U.S. and are adjacent to wetlands, pose a direct threat to frogs because these cultivated grasslands are primary locations for summer occupancy. When conservation land managers are selecting sites for acquisition or restoration they should avoid investments that will situate the wetland adjacent to heavily travelled roads and agricultural lands likely to be mowed or hayed. Increasing habitat amount and quality at amphibian breeding, feeding and wintering sites should reduce the energy required and hazards associated with moving long distances. Large, diverse wetlands probably provide all of the requirements needed by Northern Leopard Frogs for survival including food, shelter, breeding and overwintering areas.

Minnesota↗

USGS2005

Breeding bird assemblages associated with stages of forest succession in large river floodplains

Floodplain forests rival all other habitat types in bird density and diversity. However, major successional changes are predicted for floodplain forests along the Mississippi River in the coming decades; young forests may replace the existing mature silver maple (Acer saccharinum L.) forests in some areas. We wanted to assess how the breeding bird community might respond to these changes. We studied stands of young forests along the middle Mississippi River, comparing the breeding bird assemblages among three stages of forest succession: shrub/scrub, young cottonwood (Populus deltoides Marshall) and willow (Salix nigra Marshall) forests, and mature silver maple dominated forests. We recorded a total of 54 bird species; the most frequently observed species were the indigo bunting (Passerina cyanea), red-winged blackbird (Agelaius phoeniceus), and yellow-billed cuckoo (Coccyzus americanus). Bird species richness differed among the habitat types, with mature forests supporting the largest number of species and the most species of management concern. The shrub/scrub and mature forest bird assemblages were distinct and shared few species, but the young forests had no identifiable bird species assemblage, sharing species found in both of the other habitat types. The bird assemblages we observed in young forests may become more prevalent as aging floodplain forests are replaced with younger stages of forest succession. Under this scenario, we would expect a temporary local decrease in bird species richness and habitat for species of management concern.

Missouri↗

USGS2004

Avian nest success in midwestern forests fragmented by agriculture

We studied how forest-bird nest success varied by landscape context from 1996 to 1998 in an agricultural region of southeastern Minnesota, southwestern Wisconsin, and northeastern Iowa. Nest success was 48% for all nests, 82% for cavity-nesting species, and 42% for cup-nesting species. Mayfield-adjusted nest success for five common species ranged from 23% for the American Redstart ( Setophaga ruticilla ) to 43% for the Eastern Wood-Pewee ( Contopus virens ). Nest success was lowest for open-cup nesters, species that reject Brown-headed Cowbird ( Molothrus ater ) eggs, species that nest near forest edges, and Neotropical migrants. The proportion of forest core area in a 5-km radius around the plot had a weakly negative relationship with daily survival rate of nests for all species pooled and for medium or high canopy nesters, species associated with interior and edge habitats, open-cup nesters, and nests located between 75 and 199 m from an edge. The proportion of forest core area was positively related to daily survival rate only for ground and low nesters. Our findings are in contrast to a number of studies from the eastern United States reporting strong positive associations between forest area and nesting success. Supported models of habitat associations changed with the spatial scale of analysis and included variables not often considered in studies of forest birds, including the proportion of water, shrubs, and grasslands in the landscape. Forest area may not be a strong indicator of nest success in landscapes where all the available forests are fragmented.

Iowa, Minnesota, Wisconsin↗

USGS2004

A hierarchical spatial model of avian abundance with application to Cerulean Warblers

Surveys collecting count data are the primary means by which abundance is indexed for birds. These counts are confounded, however, by nuisance effects including observer effects and spatial correlation between counts. Current methods poorly accommodate both observer and spatial effects because modeling these spatially autocorrelated counts within a hierarchical framework is not practical using standard statistical approaches. We propose a Bayesian approach to this problem and provide as an example of its implementation a spatial model of predicted abundance for the Cerulean Warbler (Dendroica cerulea) in the Prairie-Hardwood Transition of the upper midwestern United States. We used an overdispersed Poisson regression with fixed and random effects, fitted by Markov chain Monte Carlo methods. We used 21 years of North American Breeding Bird Survey counts as the response in a loglinear function of explanatory variables describing habitat, spatial relatedness, year effects, and observer effects. The model included a conditional autoregressive term representing potential correlation between adjacent route counts. Categories of explanatory habitat variables in the model included land cover composition and configuration, climate, terrain heterogeneity, and human influence. The inherent hierarchy in the model was from counts occurring, in part, as a function of observers within survey routes within years. We found that the percentage of forested wetlands, an index of wetness potential, and an interaction between mean annual precipitation and deciduous forest patch size best described Cerulean Warbler abundance. Based on a map of relative abundance derived from the posterior parameter estimates, we estimated that only 15% of the species' population occurred on federal land, necessitating active engagement of public landowners and state agencies in the conservation of the breeding habitat for this species. Models of this type can be applied to any data in which the response is counts, such as animal counts, activity (e.g.,nest) counts, or species richness. The most noteworthy practical application of this spatial modeling approach is the ability to map relative species abundance. The functional relationships that we elucidated for the Cerulean Warbler provide a basis for the development of management programs and may serve to focus management and monitoring on areas and habitat variables important to Cerulean Warblers.

Ecological Applications↗

USGS2004

Commentary: A cautionary tale regarding use of the National Land Cover Dataset 1992

Digital land-cover data are among the most popular data sources used in ecological research and natural resource management. However, processes for accurate land-cover classification over large regions are still evolving. We identified inconsistencies in the National Land Cover Dataset 1992, the most current and available representation of land cover for the conterminous United States. We also report means to address these inconsistencies in a bird-habitat model. We used a Geographic Information System (GIS) to position a regular grid (or lattice) over the upper midwestern United States and summarized the proportion of individual land covers in each cell within the lattice. These proportions were then mapped back onto the lattice, and the resultant lattice was compared to satellite paths, state borders, and regional map classification units. We observed mapping inconsistencies at the borders between mapping regions, states, and Thematic Mapper (TM) mapping paths in the upper midwestern United States, particularly related to grass I and-herbaceous, emergent-herbaceous wetland, and small-grain land covers. We attributed these discrepancies to differences in image dates between mapping regions, suboptimal image dates for distinguishing certain land-cover types, lack of suitable ancillary data for improving discrimination for rare land covers, and possibly differences among image interpreters. To overcome these inconsistencies for the purpose of modeling regional populations of birds, we combined grassland-herbaceous and pasture-hay land-cover classes and excluded the use of emergent-herbaceous and small-grain land covers. We recommend that users of digital land-cover data conduct similar assessments for other regions before using these data for habitat evaluation. Further, caution is advised in using these data in the analysis of regional land-cover change because it is not likely that future digital land-cover maps will repeat the same problems, thus resulting in biased estimates of change.

Wildlife Society Bulletin↗

USGS2000

Patterns of artificial nest depredation in a large floodplain forest

We used artificial bird nests to examine the relative effects of local habitat features and the surrounding landscape on the probability of songbird nest depredation in floodplain forests of the Upper Mississippi River. We found that the probability of depredation increased with size of floodplain forest plots. In small plots, the probability of depredation tended to increase away from the forest edge. Small patches of floodplain forest within a large river system can provide valuable nesting habitat for songbirds. We suggest that depredation pressure may be lower due to isolation effects. The probability of nest depredation increased with increasing canopy cover surrounding the nest tree and decreasing cover around the nest. Managers seeking to discourage nest predators in floodplain forests should consider managing for habitats that supply dense cover for nest concealment and an open tree canopy.

Iowa, Minnesota, Wisconsin↗