Land Use – Land Cover Conversion, Regeneration and Degradation in the High Elevation Bolivian Andes

Regional land-cover change affects biodiversity, hydrology, and biogeochemical cycles at local, watershed, and landscape scales. Developing countries are experiencing rapid land cover change, but assessment is often restricted by limited financial resources, accessibility, and historical data. The assessment of regional land cover patterns is often the first step in developing conservation and management plans. This study used remotely sensed land cover and topographic data (Landsat and Shuttle Radar Topography Mission), supervised classification techniques, and spectral mixture analysis to characterize current landscape patterns and quantify land cover change from 1985 to 2003 in the Altiplano (2535–4671 m) and Intermediate Valley (Mountain) (1491–4623 m) physiographic zones in the Southeastern Bolivian Andes. Current land cover was mapped into six classes with an overall accuracy of 88% using traditional classification techniques and limited field data. The land cover change analysis showed that extensive deforestation, desertification, and agricultural expansion at a regional scale occurred in the last 20 years (17.3% of the Mountain Zone and 7.2% of the Altiplano). Spectral mixture analysis (SMA) indicated that communal rangeland degradation has also occurred, with increases in soil and non-photosynthetic vegetation fractions in most cover classes. SMA also identified local areas with intensive management activities that are changing differently from the overall region (e.g., localized areas of increased green vegetation). This indicates that actions of local communities, governments, and environmental managers can moderate the potentially severe future changes implied by the results of this study.     

Induction of adventitious buds on roots of the potato

Auxin treatment of de-eyed potato slices induced root formation. When the roots were exposed to light, adventitious buds were formed.This method for bud formation may be used to produce non-chimerical potato mutants, when the buds can be obtained from mutagenically treated tissue. An additional purpose is the investigation of the L₃ of existing mutants.This investigation was supported by the EURATOM-ITAL Association, Wageningen, The Netherlands.     

Population demography and fecundity do not decline with habitat fragmentation in the rainforest tree Macadamia integrifolia (Proteaceae)

Habitat fragmentation is often associated with reduced levels of fitness and local extinction of plant species, and consequently poses a major threat to the persistence of species worldwide. The majority of demography-based fragmentation studies to date have focussed primarily on fragmentation impacts on individual plant fecundity. Here we investigate the impact of habitat fragmentation on the demography (plant height classes and density) and key population dynamic processes for the rainforest tree species Macadamia integrifolia (Proteaceae). Raceme and fruit production and seedling emergence across fragmented sites exceeded that in more intact sites with no apparent difference in short-term mortality rates. Fecundity of flowering trees did not appear to be affected by fragmentation. Instead, overall reproductive output in fragmented sites was enhanced relative to undisturbed sites due to a higher proportion of reproductively active individuals. The probability of flowering and fruiting was negatively correlated with the projected foliage cover (PFC) surrounding individual trees, and average PFC was significantly lower in small and medium fragments, suggesting light availability as a potential contributor to the trends observed here.This study demonstrates that the short-term effects of habitat fragmentation on population viability may not necessarily be detrimental for some species, and highlights the importance of assessing not only the fecundity of flowering individuals but also the proportion of individuals reproducing within fragments.     

Feline mammary adenocarcinoma: tumor size as a prognostic indicator

Mammary carcinomas and adenocarcinomas (MACs) are relatively common tumors in cats. The postexcisional survival period of affected cats is inversely proportional to tumor size, but the reported median survival periods for different tumor size categories is quite variable. This variability diminishes the prognostic value of reported data. In our study, cats with MACs greater than 3 cm in diameter had a 12-month median survival period, whereas those with MACs less than 3 cm in diameter had a 21-month survival period. Survival periods for cats with MACs smaller than 3 cm ranged from 3 to 54 months; therefore, tumor size alone is of limited prognostic value in cats with MACs smaller than 3 cm in diameter. In cats with MACs larger than 3 cm in diameter, tumor size appears to have much higher prognostic relevance, because this study, as well as others, have indicated that cats with MACs greater than 3 cm in diameter have a poor prognosis, with median survival periods ranging from 4 to 12 months.     

Vegetative propagation of Beta vulgaris by leaf cuttings

Summary Leaf cuttings without axillary buds were made from young vegetative beet plants. Roots were formed at the petiole end. Adventitious bud formation occurred at a very low frequency and could not be stimulated by application of growth regulators. Leaf cuttings with axillary buds formed plants at a higher frequency but development of buds into shoots was slow and irregular. As no vascular connections were found between petiole and axillary bud, the slow growth of the buds was attributed to insufficient supply of assimilates from the leaves. Axillary buds rapidly developed into shoots when petiole explants with buds were placed on culture media. Nearly all cultures, however, were contaminated with bacteria that originated from the inner tissue of the explants.     

Cats and calcium oxalate: strategies for managing lower and upper tract stone disease

PRACTICAL RELEVANCE: Calcium oxalate (CaOx) containing stones are among the most common of the urinary tract stones identified in cats. RISK FACTORS: Risk factors for CaOx stone formation include such things as breed, gender and diet; stress and obesity have also been hypothesized to be risk factors for this disease. MANAGEMENT APPROACH: A tailored, individual management strategy for preventing CaOx stone recurrence is important and should include addressing the diet, environment and any other comorbid conditions present. Increasing the cat's moisture intake is one of the key mechanisms for preventing recurrence. CLINICAL CHALLENGES: CaOx ureterolithiasis has emerged as a difficult and sometimes life-threatening problem for cats. In those cats where stones are found incidentally, periodic monitoring may be required to assess for disease progression. Interventional procedures such as ureteral stent placements are now increasingly being performed for recurrent cases or those with larger stone burdens. Periodic radiographs for more severe cases and frequent client communication can help ensure successful outcomes for cats with lower and upper CaOx stone disease. EVIDENCE BASE: Limited evidence-based studies are published regarding management of feline upper and lower urinary tract CaOx stone disease, making this a difficult condition to manage in some cats. Studies designed to evaluate the relationship to dietary modifications, medical management, stress, obesity and surgical techniques are warranted in cats with upper and lower urinary tract CaOx stones.