Marsh Tit Poecile palustris territories in a British broad-leaved wood

We used individual colour-marking and territory mapping to quantify the spatial extent of 32 Marsh Tit Poecile palustris territories in Monks Wood, eastern England, during spring of the years 2002–04. A mean territory size of 4.1 ha was identified. All 2004 spring territories were located, allowing a breeding density of 14 pairs/km² to be calculated. Availability of airborne digital remote sensing (LiDAR) data for Monks Wood allowed the characterization of the canopy structure in territories and non-breeding areas using a three-dimensional canopy-height model. The difference between the mean canopy height of the 2004 territories and that of the unoccupied area of the study site in the same year was 1.8 m, or 14%. Sampling the unoccupied area, with hypothetical 'pseudo-territories', showed a statistically significant difference of 1.6 m (13%) between the mean canopy heights of the 'taller' 2004 territories and the unoccupied pseudo-territories. A comparison by field survey of tree and shrub species composition between the 2004 territories and pseudo-territories found no difference in species richness or the mean density of shrubs or mature trees (> 30 cm diameter at breast height, dbh). The mean density of medium-sized (5–30 cm dbh) and small (< 5 cm dbh) trees was, respectively, 1.9 and 3.9 times greater in the pseudo-territories, values that were statistically significant. Overall, Marsh Tits in Monks Wood appeared to require mature trees with a shrub layer beneath the top canopy, but avoided areas with large numbers of young and immature trees.     

Serological relationships among antigens of the BoLA and the bovine M blood group systems

Alloimmunizations with either lymphocytes or red cells from donor cows positive for BoLA w16 and blood group M' antigens into recipients negative for these antigens produced antisera reactive in the cytotoxic test with w16-positive lymphocytes and in the haemolytic test with M'-positive erythrocytes. Similarly, alloimmunizations of blood group M1-negative recipients with either lymphocytes or red cells from donor cows possessing the M1 blood group factor produced antisera specifically reactive with lymphocytes and erythrocytes from M1-positive cattle. Absorptions with either lymphocytes or erythrocytes from individual animals of the same M antigenic type as the donor removed all haemolytic and cytotoxic reactivity. The results indicate that blood group M' and BoLA w16 share a similar antigenic structure. Likewise, blood group M1 has an antigenically similar counterpart which is also part of the BoLA system.     

Sustainable forestry: A model of the effects of nitrogen removals in wood harvesting and fire on the nitrogen balance of regrowth eucalypt stands

Abstract Sustainable forest use is an integral part of Australia's recently adopted National Forest Policy; consequently, there is an urgent need for quantitative, ecologically based measures of sustainability. One process that may affect ecosystem sustainability is the removal of nutrients through forest harvesting and fire. This paper presents a model-based analysis of the combined consequences of harvesting and fire management practices for the nitrogen (N) budgets of managed forest ecosystems. The model, called N-BAL, evaluates the balance between N removals due to harvesting and fire (prescribed and regeneration burns), and N inputs (both natural and as added fertilizer), and leads to a criterion for the maintenance of site N reserves. That criterion can be used to estimate the accretion (or depletion) of site N over a single forest rotation, or to predict sustainable stem productivity for given N inputs and management practices. The analysis is applied to managed stands of karri (Eucalyptus diversicolor F. Muell.) in southwestern Australia to investigate whether natural N inputs are sufficient to maintain site N capital under current harvesting and fire practices. Model predictions for stands harvested at age 100 years with slash burns and regular prescribed burns range from a rotation-averaged depletion rate of 22 kg ha^?1 year^?1 to an annual accretion of 14 kg ha^?1 year^?1, depending on assumed N inputs and fire frequency and intensity. The mean annual N balance is highly sensitive to rates of natural N inputs, fire intensity and inter-fire period, and less sensitive to rotation length. These results are tentative and highlight the need for further research to improve estimates of several key model parameters and relationships.     

WIREWORM POPULATIONS IN RELATION TO CROP PRODUCTION: IV. POPULATION CHANGES DURING A BARE FALLOW

Changes in wireworm populations during a bare fallow were studied on twenty-three fields in 1943 and 1944. In every case populations were much reduced, sometimes to less than 10% of the original level. Wireworms of all sizes were affected, but the larvae less than 5 mm. in length were practically eliminated from the populations.
Evidence is presented that the reduction achieved is greater in fields ploughed in February and March than in fields ploughed in May.
As the populations in the grass 'controls' decline during the same period the entire reduction cannot be attributed to the fallow. The reduction in the bare fallow, however, differs from that in the controls in that it is permanent and continues through the autumn when the counts on the 'controls' are rising.
The practical implications of the results are discussed.     

Relationship of queen number and queen relatedness in multiple-queen colonies of the fire ant Solenopsis invicta

1. The relationship between the number of queens per nest and their relatedness was examined in the polygyne (multiple queens per nest) social form of the fire ant Solenopsis invicta .
2. No significant relationship between these two variables was found. Moreover, the overall average relatedness among nestmate queens was not significantly different from zero.
3. These findings indicate that polygyne nests of S. invicta do not represent closed societies. Furthermore, they are consistent with continual acceptance of non-nestmate queens throughout a colony's lifetime. This strategy differs from the expectation of kin selection theory that only related queens should be accepted as new reproductives within polygyne colonies.
4. The postulated acceptance of non-nestmate queens is associated with a decrease in the number of parasites, predators and diseases and a concomitant increase in the density of nests in introduced populations, suggesting that the permissive environment experienced by introduced fire ants may have decreased the relative importance of kinship as a stabilizing factor in the evolution of polygyny.