Livestock grazing has minimal effect on the species richness and diversity of semi-arid shrubland in the Western Little Karoo,South Africa     

Nelmarie Saayman  Craig Morris  Hannes Botha 《African Journal of Range and Forage Science》2016,33(4):225-233

The Succulent Karoo, one of two arid biodiversity hotspots in the world, is known for its high plant species richness, but little is known about the influence of topography and how it mediates the potentially deleterious effects of grazing. Changes in vegetation species composition, cover and species diversity were examined along piosphere gradients on northerly slopes, bottomlands and low-lying plains on 45 farms. Landscapes differed in the plant speciesand life-form composition, species richness and cover, with the more species-rich, heterogeneous grassy northerly slopes distinct from the plains and bottomlands, which were dominated by Pteronia pallens, Psilocaulon junceum and Drosanthenum spp. with more annual and ephemeral species. Overall, species richness declined linearly with decreasing rangeland condition. A weak grazing effect was detected only on the north-facing slopes, where shrubs and grass decreased with intense grazing. Years of overgrazing have resulted in the widespread dominance of P. pallens, especially on the plains and bottomlands, rendering them insensitive to grazing. The current condition of the northern slopes should be maintained and managed such that palatable species can spread to more degraded areas of the landscape.  相似文献   

Die Salemer Lärche im Bodenseegebiet     

Hannes Mayer 《European Journal of Forest Research》1964,83(11-12):321-350

  相似文献   

III. Buchbesprechungen     

A. Baumgartner  Hannes Mayer 《European Journal of Forest Research》1964,83(7-8):255-256

  相似文献   

Zur Übertragbarkeit waldbaulicher Folgerungen in vergleichbaren tannenreichen Waldgesellschaften (Abieti-Fagetum und Abietetum) der nördlichen West- und Ostalpen     

Hannes Mayer 《European Journal of Forest Research》1964,83(1-2):38-63

  相似文献   

III. Buchbesprechungen     

Speer  Hannes Mayer  Abetz 《European Journal of Forest Research》1958,77(3-4):126-128

  相似文献   

III. Buchbesprechungen     

Mägdefrau  E. Rohmeder  A. Baumgartner  Hannes Mayer 《European Journal of Forest Research》1957,76(11-12):382-384

  相似文献   

Prof. Dipl. Ing. Dr. Dr. h. c. Leo Tschermak zum Gedenken     

Hannes Mayer 《European Journal of Forest Research》1969,88(1):378-379

Ohne Zusammenfassung  相似文献   

Breed Differences in Natriuretic Peptides in Healthy Dogs     

K. Sjstrand  G. Wess  I. Ljungvall  J. Hggstrm  A‐C. Merveille  M. Wiberg  V. Gouni  J. Lundgren Willesen  S. Hans  A‐S. Lequarr  L. Mejer Srensen  J. Wolf  L. Tiret  M. Kierczak  S. Forsberg  K. McEntee  G. Battaille  E. Seppl  K. Lindblad‐Toh  M. Georges  Hannes Lohi  V. Chetboul  M. Fredholm  K. Hglund 《Journal of veterinary internal medicine / American College of Veterinary Internal Medicine》2014,28(2):451-457

Background

Measurement of plasma concentration of natriuretic peptides (NPs) is suggested to be of value in diagnosis of cardiac disease in dogs, but many factors other than cardiac status may influence their concentrations. Dog breed potentially is 1 such factor.

Objective

To investigate breed variation in plasma concentrations of pro‐atrial natriuretic peptide 31‐67 (proANP 31‐67) and N‐terminal B‐type natriuretic peptide (NT‐proBNP) in healthy dogs.

Animals

535 healthy, privately owned dogs of 9 breeds were examined at 5 centers as part of the European Union (EU) LUPA project.

Methods

Absence of cardiovascular disease or other clinically relevant organ‐related or systemic disease was ensured by thorough clinical investigation. Plasma concentrations of proANP 31‐67 and NT‐proBNP were measured by commercially available ELISA assays.

Results

Overall significant breed differences were found in proANP 31‐67 (P < .0001) and NT‐proBNP (P < .0001) concentrations. Pair‐wise comparisons between breeds differed in approximately 50% of comparisons for proANP 31‐67 as well as NT‐proBNP concentrations, both when including all centers and within each center. Interquartile range was large for many breeds, especially for NT‐proBNP. Among included breeds, Labrador Retrievers and Newfoundlands had highest median NT‐proBNP concentrations with concentrations 3 times as high as those of Dachshunds. German Shepherds and Cavalier King Charles Spaniels had the highest median proANP 31‐67 concentrations, twice the median concentration in Doberman Pinschers.

Conclusions and Clinical Importance

Considerable interbreed variation in plasma NP concentrations was found in healthy dogs. Intrabreed variation was large in several breeds, especially for NT‐proBNP. Additional studies are needed to establish breed‐specific reference ranges.  相似文献   

Fate of heavy metals in a strongly acidic shooting‐range soil: small‐scale metal distribution and its relation to preferential water flow     

Lars A. Knechtenhofer  Irene O. Xifra  Andreas C. Scheinost  Hannes Flühler  Ruben Kretzschmar 《植物养料与土壤学杂志》2003,166(1):84-92

To assess the mobility of Pb and associated metals in a highly contaminated shooting range soil (Losone, Ticino, Switzerland), we investigated the spatial distribution of the metals and their relation to preferential water flow paths. A 2.2 m² plot located 40 m behind the stop butt was irrigated with a solution containing bromide and Brilliant Blue, a slightly sorbing dye. A soil profile 50 cm in width was sampled down to 80 cm with a spatial resolution of 2.5 cm, resulting in 626 samples. Concentrations of elements (12 ≤ Z ≤ 92) were determined by energy‐dispersive Xray fluorescence spectrometry, and Brilliant Blue concentrations were determined with a chromameter. In the acidic (pH 3), organic matter‐rich, well drained Dystric Cambisol, maximum concentrations of 80.9 g kg^‐1 Pb, 4.0 g kg^‐1 Sb, and 0.55 g kg^‐1 Cu were measured in the topsoil. Within 40 cm soil depth, however, Pb, Sb, and Cu approached background concentrations of 23 mg kg^‐1, 0.4 mg kg^‐1, and 9.4 mg kg^‐1, respectively. The even horizontal distribution and the steep gradient along soil depth indicate tight metal binding in the topsoil, and a fairly homogeneous transport front. In contrast, water flow through the profile was highly heterogeneous. In the uppermost 20 cm, preferential flow was initiated by heterogeneous infiltration at the soil surface, but had no influence on metal distribution. Below 20 cm, however, preferential flow originated from larger tree roots, and metal concentrations were significantly elevated along these macropores. Spatial distributions of Pb, Sb, and Cu were similar, suggesting that all three metals are strongly retained in the topsoil and transported along preferential water flow paths in the subsoil.  相似文献   

Identifying, understanding, and describing spatial processes in agricultural landscapes — four case studies     

Ole Wendroth  Peter Jürschik  K. Christian Kersebaum  Hannes Reuter  Chris van Kessel  Donald R. Nielsen 《Soil & Tillage Research》2001,58(3-4):113-127

To evaluate the quality of the ecosystem and for making resources and land management decisions landscapes have to be assessed quantitatively. For a better understanding of landscape processes and their characterization, the analysis of the inherent variability is a major factor. Four case studies in which problems associated with landscape analysis are discussed. Spatial processes remain a main focus, as their analysis provides information on the relation between relevant state variables in agricultural landscapes. Variogram analysis showed that mineral soil nitrogen (N_min) sampled in a field at different scales, domains, and times is an instationary spatial process. Spatial association of grain yield, soil index and remotely sensed vegetation index may not be identifiable from kriged contour maps as local coincidence may be obscured behind classified areas. Crop yield in subsequent years and remotely sensed information are not related if a unique response is assumed. An alternative data stratification procedure is described here for the identification of different response functions in agricultural ecosystems. Processes of crop yield and underlying variables are described in autoregressive state-space models. This technique incorporates both deterministic and stochastic relations between different variables and is based on relative changes in space.  相似文献