257 research outputs found
Die geologische und archäologische Stellung des altpaläolithischen Fundplatzes Markkleeberg bei Leipzig
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Effects of Patch Burning and Grazing Exotic-Grass Monocultures on Northern Bobwhite Habitat and Productivity
Buffelgrass (Pennisetum ciliare) is an invasive, exotic grass that threatens biodiversity and wildlife habitat throughout the southwest. This is especially true for northern bobwhites (Colinus virginianus). Bobwhite populations have decreased over the past century because of a loss in habitat and usable space. Use of exotic grass monocultures by quail tends to be limited to edges adjacent to woody plant communities. We evaluated if creating a mosaic of small prescribed burns followed by intense cattle grazing in exotic-grass monocultures will increase usable space for bobwhites and increase bobwhite abundance in La Salle County, Texas. We randomly assigned a patch burn-graze treatment to 2,200-ha pastures dominated by buffelgrass and randomly selected 2 experimental controls (grazing only) to 2,200-ha pastures. We burned patches totaling 25% of each pasture in January 2010 and allowed grazing after burned grass reached 15 cm in height. Grazing intensity (standing crop removal) was sampled in June and August 2010. Patch-burning and grazing resulted in more heterogeneity in standing crop of buffelgrass (P , 0.001). Bobwhites appeared to use exotic grass monocultures in burned patches with a greater abundance of native forbs and woody plants during the first year of study. Bobwhites avoided areas where there was no native vegetation, and their abundance was closely associated with brushy riparian areas (P 1⁄4 0.09). There were no differences (P . 0.05) in bobwhite abundance between treatment and control pastures. Severe drought during the first year of study may have affected the results
The Forgotten Quail Decline: The Plight of Scaled Quail in Texas
Several quail species are experiencing range-wide declines in the United States. The northern bobwhite (Colinus virginianus) has garnered the most attention, both from a research and conservation perspective. The bobwhite decline in Texas, has resulted in considerable time and effort being devoted to research and management on the species due to its status as a highly popular and economically important game bird. This attention has been beneficial to bobwhite conservation and management but, an unfortunate consequence of this focus has been neglect of the scaled quail (Callipepla squamata) that has been declining at even a more alarming rate. Scaled quail, according to Breeding Bird Survey (BBS) data, have declined at a rate of 5.1% per year in the Tamaulipan Biotic Province (southern Texas), the greatest of any region surveyed in its geographic range. Anecdotal reports of landowners have long noted the gradual disappearance of scaled quail and concomitant replacement with northern bobwhite throughout southern Texas, beginning since about the 1990s. Analysis of BBS data provides evidence for this replacement. Percent of quail detections in the core of the scaled quail range in the Tamaulipan Biotic Province were 80:20 (scaled quail: bobwhite) during the 1960s but currently represent about 5:95. In addition, the range of scaled quail has been contracting, moving progressively west with time. The species is no longer detected on the easternmost BBS routes in southern Texas
Assessing pollen beetle dynamics in diversified agricultural landscapes with reduced pesticide management strategies: Exploring the potential of digital yellow water traps for continuous, high-resolution monitoring in oilseed rape
The European Farm to Fork strategy strives to reduce pesticide use and risk by 50% by 2030, preserving agricultural productivity, biodiversity, and human health. Novel research on crop diversification and new field arrangements, supported by digital technologies, offers sustainable innovations for pest control. This study evaluates digital yellow water traps, equipped with a camera and associated artificial intelligence model for continuous pollen beetle monitoring in diversified agricultural landscapes. Data were collected in oilseed rape from three harvest years (2021-2023) at the experimental site patchCROP, a landscape experiment established to study the effects of spatial and temporal crop diversification measures on yield, ecosystem services, and biodiversity. In patchCROP, crops were planted in smaller, 0.5 ha (72 × 72 m) squares called "patches" with different pesticide management strategies and were compared to surrounding commercial fields. The digital yellow water traps and AI were evaluated and found to be useful for gauging pollen beetle immigration into the crop. Across all years, higher insect pest pressure was recorded in the patches compared to commercial fields but did not necessarily compromise yields. Implementation of pesticide management strategies, including targeted insecticide applications at specific insect pest thresholds, were not associated with reduced yields in patches with flower strips. Future studies should consider examining the role of field size and alternative diversification approaches to fine-tune insecticide reduction strategies at the landscape scale
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