Additive partitioning of plant species diversity in an agricultural mosaic landscape

In this paper, we quantify the effects of habitat variability and habitat heterogeneity based on the partitioning of landscape species diversity into additive components and link them to patch-specific diversity. The approach is illustrated with a case study from central Switzerland, where we recorded the presence of vascular plant species in a stratified random sample of 1'280 quadrats of 1 m² within a total area of 0.23 km². We derived components of within- and between-community diversity at four scale levels (quadrat, patch, habitat type, and landscape) for three diversity measures (species richness, Shannon index, and Simpson diversity). The model implies that what we measure as within-community diversity at a higher scale level is the combined effect of heterogeneity at various lower levels. The results suggest that the proportions of the individual diversity components depend on the habitat type and on the chosen diversity aspect. One habitat type may be more diverse than another at patch level, but less diverse at the level of habitat type. Landscape composition apparently is a key factor for explaining landscape species richness, but affects evenness only little. Before we can test the effect of landscape structure on landscape species richness, several problems will have to be solved. These include the incorporation of neighbourhood effects, the unbiased estimation of species richness components, and the quantification of the contribution of a landscape element to landscape species richness.     

Dynamics of anthocyanin and flavonol profiles in the ‘Crimson Seedless’ grape berry skin during development and ripening

‘Crimson Seedless’ grapes (Vitis vinifera L.) do not develop adequate berry colour in different parts of the world including Australia and USA leading to serious economic losses to the growers. In the present study, various anthocyanins and flavonols were identified in the skin of the ‘Crimson Seedless’ grape berries using LC/PDA/ESI-MS and their changes in the berry skin during development and ripening of ‘Crimson Seedless’ grape berries were investigated during 2005–2006 and 2006–2007. Eleven anthocyanins and two flavonols were identified in the berry skin using LC/PDA/ESI-MS. Of the anthocyanins identified, four anthocyanins including cyanidin 3-O-(6″-O-acetyl)-glucoside, peonidin 3-O-(6″-O-acetyl)-glucoside, malvidin 3-O-(6″-O-acetyl)-glucoside and malvidin 3-O-(6″-O-coumaroyl)-glucoside were not reported earlier. During both the years, the concentration of the 3-O-glucosides of delphinidin, petunidin, peonidin, and malvidin as well as the acetyl and coumaroyl esters of the 3-O-glucosides of cyanidin, peonidin, and malvidin in the berry skin increased during berry development and ripening. During 2006–2007, the concentration of cyanidin 3-O-glucoside in the berry skin increased during the early stages of berry ripening and subsequently declined till harvest while in 2005–2006, the concentration increased during the initial phase of berry ripening and remained relatively stable thereafter till harvest. The concentration of total anthocyanins in the berry skin was higher during 2006–2007 as compared to 2005–2006. During both years, the concentration of quercetin 3-O-glucoside in the berry skin increased during berry development and ripening while the concentration of quercetin 3-O-glucuronide in the berry skin decreased during the same period. To the best of our knowledge, this is the first report on the evolution of different anthocyanins and flavonols in the ‘Crimson Seedless’ berry skin during berry development and ripening.     

Molecular characterization of Hawaiian Sugarcane yellow leaf virus genotypes and their phylogenetic relationship to strains from other sugarcane-growing countries

Sugarcane yellow leaf virus (SCYLV) is the causal agent of the sugarcane disease Yellow leaf (YL), which was first reported in Hawaii. The presence of SCYLV was detected by tissue blot immunoassay and the Hawaiian sugarcane cultivars fell into susceptible cultivars (with SCYLV) and resistant cultivars (without SCYLV). RT-PCR showed recently that the resistant cultivars also contain the virus, however with a 100-fold lower virus titre than in the susceptible cultivars. SCYLV is present as whole genome (6 kb) or as two subgenomic sequences of 2.4 and 1.0 kb. Virus preparations from three Hawaiian cultivars (one resistant and two susceptible) were fully sequenced and the sequences were aligned to published, full and partial sequences. The phylograms corroborate previous findings that the so-called YLS-segment, which codes for the coat protein, shows the least genetic diversity, whereas the other sequence fragments A–D, representing the ORFs 0–5, expressed a two-fold higher diversity. The Hawaiian SCYLV-strains clustered together next to the Peru strain, apart from the BRA-strains and well apart from the REU-strains. We propose that the Hawaiian SCYLV should be considered as an independent group together with the Peru strain and known as HAW-PER. The sequences from the two susceptible cultivars had a deletion of 48 to 54 nt in ORF1, which codes for the gene silencing suppressor and a RNA-dependent RNA-polymerase. It is speculated that this deletion is important for the high proliferation rate of the virus in the susceptible plants.     

An epidemiological study of sheep deaths before and during export by sea from Western Australia

A study was conducted to record the deaths that occurred during export, and to examine the temporal pattern of pellet feeding in the feedlot and ascertain the variation in mortality between groups of sheep from different farms. Between November 1985 and April 1987, 5 cohorts of sheep were selected on arrival at a feedlot before live export by sea from Western Australia to the Middle East. Each cohort consisted of 4,118 to 9,612 Merino wethers from 15 to 35 farms (lines). There were few deaths during trucking to the feedlot (rate 0.9, range 0.0 to 3.0 per 10,000 sheep) and during lot-feeding (rate 6.2, range 1.2 to 12.2 per 10,000 sheep). Most of the deaths occurred aboard ship (rate 210.7, range 152.7 to 271.5 per 10,000 sheep). The proportion of sheep that ate pelleted feed increased with increasing length of time in the feedlot. By the end of lot-feeding the percentage of sheep that had not eaten pellets was 23.3, 4.4, 1.2, 2.1 and 0.2 in a representative sample of each of the 5 cohorts. It was considered that offering hay throughout lot-feeding was undesirable for the purpose of maximising the number of sheep that ate pellets before loading on the ship. Half of the deaths aboard ship occurred in 25% of 133 lines of sheep in the 5 cohorts. In each cohort the median per cent death rate (and range) per line was 1.3 (0.3 to 11.9), 1.1 (0.0 to 5.7), 1.8 (0.0 to 6.8), 2.3 (0.0 to 14.3) and 0.9 (0.1 to 5.4).(ABSTRACT TRUNCATED AT 250 WORDS)