Comparing grazing and resting electivity of beef cattle for BC bunchgrass communities using GPS collars

Thompson, D., Wheatley, B. J., Church, J. S., Newman, R. and Walker, J. 2015. Comparing grazing and resting electivity of beef cattle for BC bunchgrass communities using GPS collars. Can. J. Anim. Sci. 95: 499–507. Grasslands in the interior of British Columbia often contain a mosaic of plant communities that provide variable habitat for free-ranging cattle. Global positioning system (GPS) collars have been used to study natural habitat use by cattle on a coarse scale (such as riparian, grassland and forested habitats), but not on a fine scale (such as choice among grassland plant communities). Cows equipped with GPS collars were tracked during the spring grazing period for 4 yr. Six grassland pastures were used as replicates. The activity (grazing or resting) of cattle at GPS locations was classified using a distance travelled algorithm. A detailed plant community map of five plant community types was constructed, and cow relative use within the plant communities was determined. Electivity, which scales for differences in community area, was used to compare the use of plant communities. While grazing, electivity for the Kentucky bluegrass community (mean +0.3) was greater than for the bluebunch wheatgrass community (mean −0.2). While resting, these differences were more pronounced. GPS collars can be used to estimate fine-scale choices among grassland communities.

A new record of Lewis’s Woodpecker, Melanerpes lewis (Gray, 1849) (Aves, Picidae) from Chihuahua, with comments on its status in Mexico

We present a new record of Lewis’s Woodpecker, Melanerpes lewis (Gray, 1849), a rare winter visitor to northern Mexico, in a riparian-grassland corridor at La Regina, Buenaventura Municipality, Chihuahua, on 11–12 January 2014. The record represents the fourth record of this species in the state, and the first record for both the northern portion of the Chihuahua region and the Mexican ecoregion level IV “Foothills and Plains with grasslands, xerophytic scrub and conifer oak forests”. We also comment on its current status and distribution in Mexico.

Water erosion and characteristics of sediment load in the Kopaninský stream basin

In May 2005, a major part of the Czech Republic was hit by an extreme rainstorm resulting in both soil erosion and flood events. We surveyed the erosion rills and soil material deposits produced by this rainstorm in the most damaged field of the experimental catchment Kopaninsky stream in the Bohemo-Moravian Highland. We measured the volume of the deposited sediment, its texture, bulk density, and other properties. The sediment consisted of two layers with a fuzzy boundary between them. The lower layer contained more fine particles, while the upper layer was mainly formed by a coarser material. The sediment generally contained lower amounts of C_ox and available nutrients than the original soil from which it was eroded. The results of the measurements were put into a broader context by using an event-based erosion prediction model ERCN, based on the curve-number method and on the Universal Soil Loss Equation. It was demonstrated that a 75 m wide riparian grassland strip in the study area was able to detain about 70% of the soil material eroded from the uphill ploughed land during the extreme rainfall-runoff event of 23^rd May 2005. It was confirmed that grassland and other vegetation strips along water courses are highly efficient in reducing the surface water pollution during extreme erosion events.

RESEARCH NOTEA comparison between reference transpiration and measurements of evaporation for a riparian grassland site

This paper compares direct measurements of evaporation with the values predicted for reference transpiration. The measurements of actual evaporation were made using an eddy correlation device on a grass field adjacent to the river Thames. Measurements of soil moisture and the driving meteorological variables were also made. The results showed that, during a period with minimal rainfall but no water stress, the cumulative values of reference transpiration compared very well with the cumulative measured evaporation and changes in soil moisture content. However, the values on specific days did not compare well. Following significant rainfall, the measured evaporation increased for a few days, probably due to evaporation of free water from the canopy or soil. Reference transpiration fell consistently below the measured evaporation once the soil moisture deficits exceeded 140 to 150 mm.

DESCRIPTION OF SACCULOZETES FILOSUS GEN.NOV., SP.NOV. AND GUATEMALOZETES DANOS SP.NOV. (ACARI: ORIBATIDA) FROM GRASSLAND HABITATS

A new genus and species, Sacculozetes filosus, is described from riparian grassland in the Soviet Far East, and a new species, Guatemalozetes danos, is described from shortgrass and alpine prairie in western North America, both on the basis of adults. The genus Guatemalozetes Mahunka is redefined; this is the first record of this genus from temperate North America. A close relationship is indicated between Sacculozetes and Lamellobates Hammer, Paralamellobates Bhaduri and Raychaudhuri, and Hypozetes Balogh. The uncertain family placement of Sacculozetes and Guatemalozetes within the Ceratozetoidea is discussed. Adults of both genera exhibit character states of the Mycobatidae, but until immatures are discovered, they are considered unplaced genera in the superfamily.