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1,143 results on '"Leuenberger P"'

206. Follow-up of the Swiss Cohort Study on Air Pollution and Lung Diseases in Adults (SAPALDIA 2) 1991–2003: methods and characterization of participants

Author

Ackermann-Liebrich, Ursula, Kuna-Dibbert, Birgit, Probst-Hensch, Nicole M., Schindler, Christian, Dietrich, Denise Felber, Stutz, Elisabeth Zemp, Bayer-Oglesby, Lucy, Baum, Felix, Brändli, Otto, Brutsche, Martin, Downs, Sara H., Keidel, Dirk, Gerbase, Margaret W., Imboden, Medea, Keller, Roland, Knöpfli, Bruno, Künzli, Nino, Nicod, Laurent, Pons, Marco, Staedele, Patricia, Tschopp, Jean-Marie, Zellweger, Jean-Pierre, Leuenberger, Philippe, and SAPALDIA team

Published
2005
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218. Mastication Fuels Did Not Alter Fire Severity or Stand Structure in an Upland Oak Woodland

Author

Arthur, Mary A, Blankenship, Beth, Leuenberger, Wendy, Winkenbach, Jordan, and Black, Devin E

Abstract

In the eastern deciduous forest region, open oak woodlands once occupied significant areas that are now closed-canopy forests, negatively affecting wildlife habitat and biodiversity. We superimposed midstory mastication and prescribed fire treatments onto sites with ice storm damage, subsequently subjected to sanitation thinning for management restoration. Mastication reduced stem density and basal area, created a variable cover of masticated material, and increased cover of forbs, graminoids, and tree regeneration. Prescribed fire was implemented two years after mastication treatment. We examined fuel changes and whether masticated fuels altered fire severity. Masticated duff depth decreased significantly two years after treatment; no change occurred on nonmasticated treatments. Masticated 1-hour fuels decreased 80% compared to 35% in nonmasticated treatments and masticated 10 h fuels decreased 45% compared to 9.6% in treatments without mastication. Prescribed fire reduced 1, 10, and 100 h fuels on the burn only treatment, and 10 h fuels on the mastication/burn treatment. Burn severity, measured by composite burn index, did not differ between treatments, nor did we measure significant effects of mastication on fire temperature or char height. Fire had no significant effect on stand structure but should be reexamined in three to five years. Repeated burning at three to five y intervals may also be beneficial.

Published
2023
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229. SAPALDIA: Methods and participation in the cross-sectional part of the Swiss Study on Air Pollution and Lung Diseases in Adults

Author

Martin, Brian W., Ackermann-Liebrich, Ursula, Leuenberger, Philippe, Künzli, Nino, Stutz, Elisabeth Zemp, Keller, Roland, Zellweger, Jean-Pierrre, Wüthrich, Brunello, Monn, Christian, Blaser, Kurt, Bolognini, Gianfranco, Bongard, Jean-Pierre, Brändli, Otto, Braun, Peter, Defila, Claudio, Domenighetti, Guido, Grize, Leticia, Karrer, Werner, Keller-Wossidlo, Harriet, Medici, Tullio C., Peeters, Annie, Perruchoud, André P., Schindler, Christian, Schoeni, Martin H., Schwartz, Joel, Solari, Gianmaria, Tschopp, Jean-Marie, and Villiger, Beat

Published
1997
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233. Posterpräsentation

Author

Erb, N., Dürig, P., Dietz, U., Müller, K., Lachat R., Dietz Th. U., Berger E., Junod M., Schneider H., Gaudin, G., Borgeat, A., Taziari, G., Borgeat, A., Valiton, A., Fahti, M., Rifat, K., Schreyer, A., Maillard-Brignon, C., Vial, Y., Hohlfeld, P., Laurini, R., Pescia, G., Schnegg, A., Leuenberger, E., Dürig, P., Hänngi, W., and Sidiropoulos, D.

Published
1995
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245. Honeysuckle (Lonicera maackii) Presence is Associated with Reduced Diversity and Richness of Flowering Spring Flora in Central Kentucky.

Author

Sena, Kenton, Gauger, Lexi, Johnson, Trinity, Shirkey, Felicity, Caldbeck, William, Hammock, Jansen, Kim, Ashley, Mazza, Bella, Pethtel, Isabelle, and Leuenberger, Wendy

Abstract

Invasive plant species can have significant, adverse effects on forest ecosystems. By outcompeting native species for resources, invasive species suppress the richness and diversity of many forest communities. This study focuses on the associations of Amur honeysuckle (Lonicera maackii Rupr.) with spring flora in Raven Run Nature Sanctuary in Lexington, Kentucky, where abundant L. maackii threatens native biodiversity. Plots were surveyed for percent herbaceous groundcover and abundance of flowering spring flora at three levels of L. maackii density (high, low, and no L. maackii). Results indicate that L. maackii abundance is associated with lower species richness, abundance, and early-season diversity of flowering native spring flora. Importantly, this study extends the existing robust literature evaluating the widespread effects of L. maackii to the Kentucky River Palisades, a sensitive and botanically important corridor in central Kentucky. [ABSTRACT FROM AUTHOR]

Published
2021
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247. Spatially explicit models reveal rodents rapidly colonize soybean fields regardless of pre-planting chemical treatment timing for cover crop removal.

Author

Nierman, Jena L., Murphy, Sean M., Leuenberger, Wendy, Davis, Allison G., Cox, John J., and Springer, Matthew T.

Subjects
COVER crops, SOYBEAN, RODENT populations, FIELD crops, RODENTS, AGRICULTURE
Abstract

Soybean (Glycine max) is among the most important field crops in the world, and the USA is a top global producer, but USA soybean losses have increased because of multitude of factors, including wildlife damage. Although small, terrestrial rodents (Order: Rodentia) are capable of causing substantial damage to soybean and other field crops. Consequently, methods need to be developed that can provide agricultural producers and wildlife managers with accurate information about rodent populations at the field-level. We conducted a multi-site, before-after-intervention study in the midwestern USA to evaluate the effectiveness of varying treatment timings for cover crop reduction/removal prior to soybean planting, which was previously posited as an effective non-lethal approach for reducing rodents in soybean fields and mitigating crop damage. We chemically treated cover crops immediately (control), at two-weeks, and at four-weeks in four fields prior to soybean planting and used hierarchical, spatially explicit models to examine the effects of treatment timing on rodent density from pre-treatment through post-emergence. The control, two-weeks, and four-weeks treatment timings resulted in 81%, 125%, and 189% average increases in rodent densities post-treatment. The number of unique individuals of each detected species also increased post-treatment for all three treatment timings. Thus, varying chemical treatment timing for reducing/removing cover crops prior to soybean planting may be an ineffective non-lethal approach for rodent population management in agroecosystems. Nonetheless, our study provides an illustrative example of an effective, multi-site methodlogy that could be used to reliably evaluate the status of rodent populations and the potential effectiveness of other rodent management methods. • Conservation practices like cover crops can inadvertently create negative human-wildlife interactions. • Spatial capture-recapture is effective at evaluating rodent densities in agricultural environments. • Rodent populations drastically increase in agricultural fields during spring despite non-lethal management practices. • Herbicide timing may be ineffective management strategy for rodents. [ABSTRACT FROM AUTHOR]

Published
2024
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249. Lung function and long term exposure to air pollutants in Switzerland. Study on Air Pollution and Lung Diseases in Adults (SAPALDIA) Team.

Author

Ackermann-Liebrich, U, Leuenberger, P, Schwartz, J, Schindler, C, Monn, C, Bolognini, G, Bongard, J P, Brändli, O, Domenighetti, G, Elsasser, S, Grize, L, Karrer, W, Keller, R, Keller-Wossidlo, H, Künzli, N, Martin, B W, Medici, T C, Perruchoud, A P, Schöni, M H, Tschopp, J M, Villiger, B, Wüthrich, B, Zellweger, J P, and Zemp, E

Published
1997
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250. One species with a disjunct distribution or two with convergent evolution? Taxonomy of two South American garlics.

Author

Sassone, Agostina B., Arroyo, Mary T.K., Arroyo‐Leuenberger, Silvia C., García, Nicolás, and Román, María José

Abstract

The establishment of species boundaries has been a difficult task for biologists since the beginning of classifications. Within South American Allioideae (= Alliaceae), the delimitation of genera and species has long been a major challenge. Consequently, species‐level nomenclature in these groups has been difficult to elucidate. Ipheion and Tristagma are two closely related South American genera for which the delimitation and circumscription of several species continue to be unclear. Tristagma sessile, a species inhabiting the Andes and the Coast Range in Chile, and Ipheion recurvifolium, a species native to Uruguay only found close to sea level, have been considered as one species with an intracontinental disjunct distribution. The divergent habitats and distributions of these taxa have stirred the question of whether they are a single species. The present study aims to elucidate the evolutionary relationships and status of the Chilean and Pampean taxa. We also analysed the name Tristagma leichtlinii, which has long been a source of confusion. Based on their phylogenetic relationships, geographical distributions, flowering periods, and DNA content, we conclude that the two taxa are different species and assignable to separate genera. We propose that the morphological similarity of Ipheion recurvifolium and Tristagma sessile, amply corroborated in this study, might be the sum of shared synapomorphies (between Ipheion and Tristagma) and convergent features. We update the biogeographic history of the two genera and propose that similar pollinators might underpin the convergence in floral traits. We outline the differences among genera and species, present a taxonomic review with a new lectotype and consider the conservation status of the studied species. [ABSTRACT FROM AUTHOR]

Published
2021
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