Filters: Tags: Emergence (X)6 results (8ms)
Emergence of the Introduced Grass Agropyron cristatum and the Native Grass Bouteloua gracilis in a Mixed-grass Prairie Restoration
Prairie restoration at the northern edge of the Great Plains can be frustrated by previously established non-native perennial grasses. We compared the emergence of a widely introduced grass, Agropyron cristatum, and a common native grass, Bouteloua gracilis, in a 4-year-old field experiment in which the Agropyron-dominated vegetation had either been left intact or treated annually with herbicide. This was done at two levels of water supply, reflecting conditions expected in wet and dry years, to examine the effects of among-year variability in precipitation. Water addition significantly increased the emergence of both surface-sown and buried (1 cm deep) seeds. Herbicide treatment of neighbors did not increase the...
Adult aquatic insect emergence, insect pesticide concentrations and water chemistry of wetlands in the Prairie Pothole Region, North Dakota, USA, 2015-16
This data release includes sampling location data, field-collected wetland attribute data, field-collected water chemistry data, laboratory-processed water chemistry data (anions, cations, alkalinity, nutrients, chlorophyll a concentrations, dissolved organic carbon, and specific ultraviolet absorbance, pesticide concentrations), dry mass of adult aquatic insects emerging from the surface of the wetlands, taxonomic classifications of the insects collected, and whole-body pesticide concentrations for adult aquatic insects emerging from wadeable wetlands in cropland and grassland landscapes across a salinity/hydrology gradient (N = 14 wetlands in 2015, N = 15 wetlands in 2016). Sampling was completed in late spring,...
Activity patterns of cave-dwelling bat species during pre-hibernation swarming and post-hibernation emergence in the central Appalachians
Bat activity around known hibernacula in Virginia and West Virginia portion of the central Appalachians during the fall swarm and spring emergence, 2015-2017
June sucker (Chasmistes liorus) spawned in the Provo River, Utah, over a 2-wk period in early June during both 1987 and 1988. Emergent larvae emigrated from the river to Utah Lake over a 2- to 3-wk period. Drift into the lake peaked between 1200 and 0400. During daylight hours, emergent larvae tended to occur in pools. Peak emergence of larval drift was approximately 1.2 larvae/m3 during late June in 1987 and 1988. Recruitment failure of June sucker is not due to reproductive failure. Published in Western North American Naturalist, volume 54, issue 4, in 1994.
Influence of warming on soil water potential controls seedling mortality in perennial but not annual species in a temperate grassland.
In a water-limited system, the following hypotheses are proposed: warming will increase seedling mortality; elevated atmospheric CO2 will reduce seedling mortality by reducing transpiration, thereby increasing soil water availability; and longevity (i.e. whether a species is annual or perennial) will affect the response of a species to global changes. Here, these three hypotheses are tested by assessing the impact of elevated CO2 (550 micromol mol(-1) and warming (+2 degrees C) on seedling emergence, survivorship and establishment in an Australian temperate grassland from autumn 2004 to autumn 2007. Warming impacts on seedling survivorship were dependent upon species longevity. Warming reduced seedling survivorship...
Juniperus woodlands are widely distributed in western North America. Few studies of seedling emergence, long-term survival, growth or mortality of the dominant Juniperus spp. in these woodlands have been carried out. Consequently, regeneration dynamics in these woodlands are poorly understood. Juniperus ashei is the dominant woody plant in the majority of woodland and savanna communities of the Edwards Plateau region in central Texas. We examined the emergence, mortality and growth of various spatial and temporal cohorts of J. ashei seedlings over an eight or nine-year period. Greatest emergence was found during the cool, mostly winter months and under the canopy of mature J. ashei trees. Emergence was significantly...