Predicting juniper encroachment and CRP effects on avian community dynamics in southern mixed-grass prairie, USA

The probability of occurrence of 30 bird species was modeled as a function of landscape covertype in northwestern Oklahoma, USA. This grassland region has been extensively fragmented by agricultural activity, and remnant grassland patches are undergoing severe degradation from encroaching juniper (Juniperus virginiana L.). In addition, many marginal or highly erodable croplands have been placed into perennial pasture dominated by exotic grasses under the Conservation Reserve Program (CRP). Based on temporal patterns of landscape change observed between 1965 and 1995, we estimated the covertype composition of the landscapes in the year 2015 under various CRP administrative and juniper expansion/control scenarios. We then used logistic regression to predict bird responses to these landscape composition estimates. Our estimates suggest that at the current rate of expansion, juniper will overtake substantial areas of remnant grassland even with extensive control measures. As a result, some obligate and facultative grassland birds are projected to decline, while numerous species tolerant of or partially reliant on woody vegetation will increase. Landscape dynamics due to changes in the CRP might be significant and could be designed to benefit declining grassland birds, but these benefits thus far are relatively minor compared to the effects encroaching juniper woodlands will have on the landscape and the avian community.     

A review of allodiversity in Lake Naivasha, Kenya: Developing conservation actions to protect East African lakes from the negative impacts of alien species

The biodiversity of developing countries is increasingly threatened by introductions of invasive alien species. This study on the allodiversity in Lake Naivasha, Kenya reviews the pathways, establishment rates and outcomes of introduced species, and provides the basis for determining conservation actions that, if implemented, could prevent potentially harmful effects of similar events in other East African lakes. Introductions into Naivasha commenced in the 1920s with the release of a sport fish and have since produced an allodiversity of 23 species. This includes species that are no longer present (e.g., some tilapia species), presumed no longer present (e.g., the Nile perch Lates niloticus) or whose distribution is highly localised and ecologically neutral (e.g., the coypu Myocastor coypus). It also includes species that established successfully and invoked major changes in lake ecology (e.g., the red swamp crayfish Procambarus clarkii) and a species that is producing apparent economic benefits to the local population (i.e., the common carp Cyprinus carpio). The most frequent donor continents were the Americas and most species were the result of secondary introductions. The main introduction vector was active release that aimed to enhance fishery production. Alien species now dominate each main level of the lake’s food web and produce impacts that are rarely restricted to a single ecosystem service. With a few exceptions, the majority of introductions translate into socioeconomic costs that contribute to rising social conflicts and exacerbating poverty. Development of appropriate conservation management tools within a regulatory framework could help protect Naivasha from further damage and could be used elsewhere in East African lakes to ensure that subsequent introductions enhance ecosystem services without affecting biodiversity.     

PREVENTION OF OVINE LUPINOSIS BY THE ORAL ADMINISTRATION OF ZINC SULPHATE AND THE EFFECT OF SUCH THERAPY ON LIVER AND PANCREAS ZINC AND LIVER COPPER

Three experiments were carried out using Merino wethers to investigate if oral administration of zinc sulphate would provide protection against the liver damage that occurs in lupinosis. At the same time, the effect of this zinc therapy on liver and pancreas zinc, and liver copper concentrations, was studied.
The zinc therapy caused increases in liver and pancreas zinc concentrations, and a drop in the liver copper concentration. Adminstration of the toxins of Phomopsis leptostromiformis with the zinc increased the magnitude of these changes.
Administration of 0.5 g zinc or greater per day, as zinc sulphate, reduced the liver damage caused by the toxins of P. leptostromiformis. The degree of liver protection provided by the zinc therapy varied both between animals within treatments and between treatments in different experiments. Zinc toxicity was encountered.     

The effect of lupinosis on liver copper, selenium and zinc concentrations in merino sheep

Merino wether weaners were exposed to toxic lupin stubbles for periods of one, two and six to nine weeks, and the effect on their liver copper, selenium and zinc concentrations studied. After the one week period there was a slight decrease in liver copper and selenium concentrations in sheep severely affected with lupinosis. This was attributed to loss of these elements from necrotic cells, and greatly increased quantities of fat in the liver. In the same period liver zinc concentrations declined and were negatively correlated with the degree of liver injury. After two weeks or more of exposure to toxic lupins a positive correlation existed between both the liver copper and selenium concentrations, and the degree of liver injury. Furthermore, total liver copper and selenium levels were also positively correlated with the degree of liver injury. Liver zinc concentrations were negatively correlated with the degree of liver injury. It is suggested that when the liver is under the influence of the toxins causing lupinosis for more than two weeks, it stores copper and selenium, and loses zinc.     

Resource constraints in petroleum production potential

Geologic reasons indicate that the dominant position of the Middle East as a source of conventional petroleum will not be changed by new discoveries elsewhere. The share of world crude oil production coming from the Middle East could increase, within 10 to 20 years, to exceed 50 percent, under even modest increases in world consumption. Nonconventional resources of oil exist in large quantities, but because of their low production rates they can at best only mitigate extant trends. Increased production of natural gas outside the United States, however, offers an opportunity for geographically diversified energy supplies in the near future.     

Halophytic shrubs accumulate minerals associated with antioxidant pathways

Halophytic shrubs from the Chenopodiaceae family are planted by farmers in Mediterranean climate and semi‐arid farming systems because they produce year‐round feed for livestock and grow on poor‐quality soils that are unfit for cereal or traditional pasture production. Halophytes have evolved in environments that exert a high oxidative stress and through this have a high antioxidant capacity. The higher antioxidant capacity of halophytes means that they could have elevated concentrations of the minerals and vitamins associated with antioxidant defence and, as a consequence, may be a good source of antioxidant minerals and vitamins for sheep, cattle and goats. It was hypothesized that a range of halophytic shrub species and accessions within species will contain copper (Cu), manganese (Mn), selenium (Se), zinc (Zn) and sulphur (S) concentrations that will exceed the requirements of grazing ruminants. Concentrations of these minerals were measured across nineteen shrub accessions representing seven widely distributed Australian chenopod species: Atriplex amnicola, Atriplex nummularia, Atriplex rhagodioides, Chenopodium nitrariaceum, Enchylaena tomentosa, Maireana brevifolia and Rhagodia preissii, as well as Eremophila glabra from the Scrophulariaceae family. Measurements were made at one location in spring and winter and at another location in winter only. Concentrations of the elements analysed almost always exceeded requirements and ranged up to 610%, 952%, 1840%, 590% and 250% of the requirement for grazing sheep for Cu, Mn, Se, Zn and S respectively. These results indicate some shrubs have significant potential for use as an antioxidant mineral supplement for ruminants.     

Phase I Clinical Trial and Pharmacokinetics of Intravesical Mitomycin C in Dogs with Localized Transitional Cell Carcinoma of the Urinary Bladder

Background: Transitional cell carcinoma (TCC) is the most common cancer of the urinary tract in dogs. The most frequent cause of death is urinary obstruction from the primary tumor. Standard medical therapy for TCC is only partially effective. Hypothesis/Objectives: Intravesical administration of mitomycin C (MMC) in dogs with invasive TCC will result in antitumor activity against the primary tumor and minimal systemic drug absorption. Animals: Thirteen privately owned dogs with naturally occurring, histopathologically diagnosed TCC of the urinary bladder. Methods: A prospective phase I trial was performed. MMC was given intravesically (600 μg/mL initial concentration) for 1 h/d for 2 consecutive days each month. The MMC concentration was escalated to a maximum of 800 μg/mL in groups of 3 dogs until the maximum tolerated dose (MTD) was determined. Serum assays for MMC were performed to determine the extent of systemic absorption of the MMC. Results: The MTD of MMC based on local toxicoses was 700 μg/mL (1‐h dwell time, 2 consecutive days). In addition, 2 dogs had severe myelosuppression and appeared to have systemic absorption of MMC. Five dogs had partial remission, and 7 dogs had stable disease. Conclusions: Intravesical MMC has antitumor activity in dogs with invasive TCC. Further study is needed to determine the cause of the myelosuppression associated with MMC administration, and to develop strategies to minimize this risk.     

Growth Regulator Herbicides Prevent Invasive Annual Grass Seed Production Under Field Conditions

Growth regulator herbicides, such as 2,4-D, dicamba, picloram, and aminopyralid, are commonly used to control broadleaf weeds in rangelands, noncroplands, and cereal crops. If applied to cereals at late growth stages, while the grasses are developing reproductive parts, the herbicides often reduce cereal seed production. We are researching methods for using this injury response to control invasive annual grasses in rangelands by depleting their short-lived seed banks. In a previous greenhouse study, we found picloram and dicamba reduced seed production of the invasive annual grass Japanese brome (Bromus japonicus Thunb.) by nearly 100%. However, this promising greenhouse finding needs to be corroborated in the field before growth regulators can be confidently recommended for invasive annual grass control. This research note describes a study conducted in eastern Montana suggesting growth regulators may provide excellent control of invasive annual grasses. Specifically, we found typical use rates of aminopyralid and picloram reduced Japanese brome seed production by more than 95% (based on sample means) when applied at three different plant growth stages. This promising result contributes to the accumulating body of evidence suggesting growth regulators may control invasive annual grasses.