26 research outputs found
Contribution of organic farming to conserving and improving biodiversity in Germany avi-fauna as an example
Although it is the aim of organic farming to increase biodiversity, there is little information about the impact of organic farming on birds. From 2001 to 2003, the number of breeding birds was recorded annually on the organic experimental farm of the Institute of Organic Farming (600 ha), and on adjacent conventional and organic farms (60 ha and 40 ha) in Northern Germany. The number of skylark (Alauda arvensis) territories increased considerably after the conversion from conventional to organic farming on the premises of the Institute. Their number remained unvaried on the conventional farm. The highest density of skylark territories was found on the farm which has been under organic management for many years. The number of yellowhammer (Emberiza citronella) territories fluctuated largely in relation to the availability of field margin strips, both on conventional and organic land. During the breeding season aerial hunters (swallows and swifts) and raptors significantly preferred organic fields. Outside the breeding season, densities of raptors (in autumn and in winter), seed-eating birds (in autumn) and insect-eating birds (in autumn) were significantly higher on organic than on conventional fields
Renal cell carcinoma: associations between tumor imaging features and epidemiological risk factors
Purpose: To investigate associations between imaging features of tumors and age, gender and body mass index (BMI) in patients with renal cell carcinoma. Method: This IRB-approved, HIPAA-compliant study included 1348 patients with histopathologically confirmed renal cell carcinoma of the clear cell subtype (ccRCC, n = 904) or non-clear cell subtype (n = 444), who underwent pre-treatment CT imaging less than 180 days before nephrectomy between 1999 and 2011. Two radiologists independently, retrospectively analyzed all imaging studies and identified features (necrosis, renal vein invasion, contact with renal sinus fat, multicystic appearance and nodular enhancement), which were then correlated with patient age, gender and BMI at time of surgery. Results: Inter-reader agreement on imaging features ranged from substantial to excellent (kappa: 0.688 to 0.982). In the ccRCC group, multicystic tumor appearance was significantly associated with lower patient age (p < 0.05) and lower BMI (p < 0.05); the presence of renal vein invasion was significantly associated with lower BMI in males (p < 0.05); and both tumor contact with the renal sinus and nodular enhancement were significantly associated with greater patient age (p < 0.05). In the non-clear cell RCC group, necrosis was associated with lower BMI for females (p < 0.05). Conclusions: This study demonstrated significant associations between imaging features of RCC and patient age and BMI, hinting an influence of these factors on tumor biology and genomic make-up. These findings could aid future studies in selecting patients while investigating genomic, molecular and metabolic variables in RCC and might potentially impact on future stratification and therapy of patients
Factors influencing awareness of community-based shorebird conservation projects in Australia
We examine the awareness of potential volunteers (n = 360) living near nine community-based shorebird conservation projects. About half of the people sampled (54%) were unaware of the nearest project. Awareness of interviewees varied substantially among projects (28-78%). Apart from gaining awareness of projects through membership of natural history groups (43%), many respondents heard of projects through friends and relatives (20%), rather than through media such as newspapers (14%) and television (2.3%). We demonstrate that community-based projects can be quantitatively and critically assessed for awareness. The use of rapid, cost-effective assessments of awareness levels has application in many conservation projects. <br /
Energy metabolic rate in breeding avocets Recurvirostra avosetta
We measured the field metabolic rates of six incubating Avocets by the doubly-labelled water method in a colony on the North-Frisian Wadden Sea coast in 1994. The Avocets had a mean field metabolic rate of 5.04 W (SD+/-0.33 W), which is only 2.3 times their basal metabolic rate as calculated by the allometric equations of KERSTEN & PIERSMA 1987. The mean water contents of the Avocets was 66.8% (SD+/-2,4%). The water efflux was very high and showed a very high variation between the birds (mean 178 ml/day, SD+/-48 ml). Avocets with a low body mass (females) tended to have both higher water contents (in %) and higher water efflux rates than Avocets with a high body mass (males); A comparison with other studies reveals, that the field metabolic rates of waders during the breeding season are strongly influenced by the geographical position of their breeding sites and the related thermostatic costs
The causes of dispersal and the cost of carry‐over effects for an endangered bird in a dynamic wetland landscape
Spatial differences in breeding success in the pied avocet Recurvirostra avosetta: effects of habitat on hatching success and chick survival
I studied the breeding biology of pied avocets Recurvirostra avosetta in natural habitats (alkaline lakes), and in semi-natural sites (dry fishpond, reconstructed wetlands) in Hungary to relate habitat selection patterns to spatial and temporal variation in breeding success. Colonies were initiated earlier in semi-natural sites than in natural habitats, and earlier on islands than on the mainland. Hatching success was higher on islands than on the mainland, in semi-natural sites than in natural habitats, in colonies of at least 15 pairs than in smaller colonies, and for nests initiated earlier than later within a colony. Fledging success was higher in the wet years (1999-2000) than in the dry year (1998), decreased strongly by season in both habitats and increased with average daily temperature in the first week post-hatch in 1999-2000. Most pairs hatching young in semi-natural sites attempted to lead their chicks to feeding areas in natural habitats, whereas no such movement occurred in the opposite direction. Chick mortality due to predation was high during brood movements and only 23% of the pairs moving their young produced fledglings, compared to 43% for pairs remaining in semi-natural sites and 68% for pairs hatching and rearing young in natural habitats (total n=192 broods). These results suggest that semi-natural sites were more suitable for nesting, whereas natural habitats were more suitable for chick-rearing. The opposing trends in habitat-related breeding success between nesting and chick-rearing suggest sub-optimal habitat selection by Pied Avocets due to an incorrect assessment of the potential for successful reproduction of semi-natural sites, which may thus function as ecological traps