20 research outputs found
Recommended from our members
Comparing Vegetation and Soils of Remnant and Restored Wetland Prairies in the Northern Willamette Valley
Most of the native wetland prairies once found in the Willamette Valley of Oregon, USA have been converted to agriculture, developed, or altered by disturbance and cessation of burning, especially in the northern portion of the valley. Mitigation efforts by Portland Metro and the NRCS have resulted in restoration of several wetland prairies, and the need for research to help assess restoration success. Here, data on vegetation and soils from three remnant wetland prairies and three restored wetland prairies in the northern Willamette Valley were analyzed to investigate whether differences among sites are related to site characteristics or management. Vascular plant species presence and percent cover data were collected from three 10 m x 10 m plots randomly located within study sites. Soil samples were collected adjacent to these plots and from nearby agricultural sites and analyzed for organic matter, moisture content, pH, and soil texture. Multivariate ordination techniques and ANOVA were used to assess differences among sites. Native species cover was higher in restorations than remnants, although remnant and restored sites did not differ in native species richness. However, NMS ordination distinguished restorations from remnants. Species such as Deschampsia cespitosa, Carex densa, Juncus tenuis and Holcus lanatus were associated with remnants, whereas Anthemis cotula, Agrostis exarata, Plagiobothrys scouleri and Veronica perigrina were associated with restorations. Soil moisture and organic matter are positively correlated with remnant status, while management attributes such as herbicide use, mowing, and cultivation of “clean crops” prior to restoration are correlated with vegetation assemblages of restorations. While some restoration goals are being met within a decade of restoration, plant communities in restorations differ from those of wetland prairie remnants.Keywords: Wetland restoration, Ecosystem services, Deschampsia cespitosaKeywords: Wetland restoration, Ecosystem services, Deschampsia cespitos
Assessing Alternative Futures of Agriculture in Iowa, U.S.A.
The contributions of current agricultural practices to environmental degradation and the social problems facing agricultual regions are well known. However, landscape-scale alternatives to current trends have not been fully explored nor their potential impacts quantified. To address this research need, our interdisciplinary team designed three alternative future scenarios for two watersheds in Iowa, USA, and used spatially-explicit models to evaluate the potential consequences of changes in farmland management. This paper summarizes and integrates the results of this interdisciplinary research project into an assessment of the designed alternatives intended to improve our understanding of landscape ecology in agricultural ecosystems and to inform agricultural policy. Scenario futures were digitized into a Geographic Information System (GIS), visualized with maps and simulated images, and evaluated for multiple endpoints to assess impacts of land use change on water quality, social and economic goals, and native flora and fauna. The Biodiversity scenario, targeting restoration of indigenous biodiversity, ranked higher than the current landscape for all endpoints (biodiversity, water quality, farmer preference, and profitability). The Biodiversity scenario ranked higher than the Production scenario (which focused on profitable agricultural production) in all endpoints but profitability, for which the two scenarios scored similarly, and also ranked higher than the Water Quality scenario in all enpoints except water quality. The Water Quality scenario, which targeted improvement in water quality, ranked highest of all landscapes in potential water quality and higher than the current landsape and the Production scenario in all but profitability. Our results indicate that innovative agricultural practices targeting environmental improvements may be acceptable to farmers and could substantially reduce the environmental impacts of agriculture in this region.Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/49340/1/LE04Santel.pd
Assessing alternative futures for agriculture in Iowa, U.S.A.
The contributions of current agricultural practices to environmental degradation and the social problems facing agricultural regions are well known. However, landscape-scale alternatives to current trends have not been fully explored nor their potential impacts quantified. To address this research need, our interdisciplinary team designed three alternative future scenarios for two watersheds in Iowa, USA, and used spatially-explicit models to evaluate the potential consequences of changes in farmland management. This paper summarizes and integrates the results of this interdisciplinary research project into an assessment of the designed alternatives intended to improve our understanding of landscape ecology in agricultural ecosystems and to inform agricultural policy. Scenario futures were digitized into a Geographic Information System (GIS), visualized with maps and simulated images, and evaluated for multiple endpoints to assess impacts of land use change on water quality, social and economic goals, and native flora and fauna. The Biodiversity scenario, targeting restoration of indigenous biodiversity, ranked higher than the current landscape for all endpoints (biodiversity, water quality, farmer preference, and profitability). The Biodiversity scenario ranked higher than the Production scenario (which focused on profitable agricultural production) in all endpoints but profitability, for which the two scenarios scored similarly, and also ranked higher than the Water Quality scenario in all endpoints except water quality. The Water Quality scenario, which targeted improvement in water quality, ranked highest of all landscapes in potential water quality and higher than the current landscape and the Production scenario in all but profitability. Our results indicate that innovative agricultural practices targeting environmental improvements may be acceptable to farmers and could substantially reduce the environmental impacts of agriculture in this region.Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/43158/1/10980_2004_Article_5253979.pd
The acquisition of auxiliary syntax: A longitudinal elicitation study. Part 1: Auxiliary BE
Purpose: The question of how and when English-speaking children acquire auxiliaries is the subject of extensive debate. Some researchers posit the existence of innately given Universal Grammar principles to guide acquisition, although some aspects of the auxiliary system must be learned from the input. Others suggest that auxiliaries can be learned without Universal Grammar, citing evidence of piecemeal learning in their support. This study represents a unique attempt to trace the development of auxiliary syntax by using a longitudinal elicitation methodology. Method: Twelve English-speaking children participated in 3 tasks designed to elicit auxiliary BE in declaratives and yes/no and wh-questions. They completed each task 6 times in total between the ages of 2;10 (years;months) and 3;6. Results: The children’s levels of correct use of 2 forms of BE (is,are) differed according to auxiliary form and sentence structure, and these relations changed over development. An analysis of the children’s errors also revealed complex interactions between these factors. Conclusion: These data are problematic for existing accounts of auxiliary acquisition and highlight the need for researchers working within both generativist and constructivist frameworks to develop more detailed theories of acquisition that directly predict the pattern of acquisition observed
The acquisition of auxiliary syntax: A longitudinal elicitation study. Part 2: The modals and auxiliary D0
Purpose: The study of auxiliary acquisition is central to work on language development and has attracted theoretical work from both nativist and constructivist approaches. This study is part of a 2-part companion set that represents a unique attempt to trace the development of auxiliary syntax by using a longitudinal elicitation methodology. The aim of the research described in this part is to track the development of modal auxiliaries and auxiliary DO in questions and declaratives to provide a more complete picture of the development of the auxiliary system in English-speaking children. Method: Twelve English-speaking children participated in 2 tasks designed to elicit auxiliaries CAN, WILL, and DOES in declaratives and yes/no questions. They completed each task 6 times in total between the ages of 2;10 (years;months) and 3;6. Results: The children’s levels of correct use of the target auxiliaries differed in complex ways according to auxiliary, polarity, and sentence structure, and these relations changed over development. An analysis of the children’s errors also revealed complex interactions between these factors. Conclusions: These data cannot be explained in full by existing theories of auxiliary acquisition. Researchers working within both generativist and constructivist frameworks need to develop more detailed theories of acquisition that predict the pattern of acquisition observed