Occurrence and present status of coastal dolphins (Delphinus delphis and Tursiops truncatus) in the eastern Ionian Sea

• 1. Boat surveys aimed at studying short‐beaked common dolphins and common bottlenose dolphins in eastern Ionian Sea coastal waters were conducted between 1993 and 2003. During 835 survey days, 24 771 km of total effort was distributed within an area of 480 km², resulting in 428 common dolphin and 235 bottlenose dolphin sightings.
• 2. Individual photo‐identification was performed extensively throughout this study, making it possible to monitor the number of animals seen in the study area each year and their long‐term residency patterns.
• 3. Common dolphins declined across the study period, from 2.18 encounters/100 km in 1997 to 0.40 encounters/100 km in 2003. In contrast, there was a relatively stable presence of bottlenose dolphins, some individuals showing high levels of site fidelity and others using the area only occasionally.
• 4. The local decline of common dolphins and the low density of bottlenose dolphins appeared to reflect the general status of these cetacean species in the wider Mediterranean region, where common dolphins were classified as endangered in the IUCN Red List in 2003.
• 5. Based on the available evidence, we infer that the present unfavourable status of common dolphins in eastern Ionian Sea coastal waters is largely a consequence of prey depletion.

Copyright © 2005 John Wiley & Sons, Ltd.     

The relative influence of catchment and site variables on fish and macroinvertebrate richness in cerrado biome streams

Landscape and site-scale data analyses aid the interpretation of biological data and thereby help us develop more cost-effective natural resource management strategies. Our study focused on environmental influences on stream assemblages and we evaluated how three classes of environmental variables (geophysical landscape, land use and cover, and site habitat), influence fish and macroinvertebrate assemblage richness in the Brazilian Cerrado biome. We analyzed our data through use of multiple linear regression (MLR) models using the three classes of predictor variables alone and in combination. The four MLR models explained dissimilar amounts of benthic macroinvertebrate taxa richness (geophysical landscape R ² ≈ 35 %, land use and cover R ² ≈ 28 %, site habitat R ² ≈ 36 %, and combined R ² ≈ 51 %). For fish assemblages, geophysical landscape, land use and cover, site habitat, and combined models explained R ² ≈ 28 %, R ² ≈ 10 %, R ² ≈ 31 %, and R ² ≈ 47 % of the variability in fish species richness, respectively. We conclude that (1) environmental variables differed in the degree to which they explain assemblage richness, (2) the amounts of variance in assemblage richness explained by geophysical landscape and site habitat were similar, (3) the variables explained more variability in macroinvertebrate taxa richness than in fish species richness, and (4) all three classes of environmental variables studied were useful for explaining assemblage richness in Cerrado headwater streams. These results help us to understand the drivers of assemblage patterns at regional scales in tropical areas.     

Morphological and biochemical changes in the muscle of the marine shrimp Litopenaeus vannamei during the molt cycle

Morphological changes and biochemical composition of abdominal muscles over the molt cycle were investigated in juvenile Litopenaeus vannamei. Eight molt stages were characterized and clear uropod images are presented. Molt frequency was highly correlated with the age of the shrimp. Juvenile shrimps appeared to molt faster at one month of age (4.6 ± 0.5 days/cycle), slow to 11.8 ± 1.7 days/cycle at three months of age, and reach a long molt cycle at six months (17.2 ± 2.7 days/cycle). Myofiber cross-sectional images revealed specific morphological changes in abdominal muscle associated with each molt stage. Expanded fiber size was observed during intermolt stages. Water content and total soluble proteins were balanced throughout the molt cycle. Total DNA concentration increased in intermolt and premolt, while total RNA concentration remained stable except in late-premolt stages. SDS-PAGE analysis showed high levels of actin and myosin in postmolt, reaching a plateau in intermolt and declining in premolt. These results suggest the occurrence of muscle fiber rearrangement in both the premolt and postmolt stages. Abdominal muscle buildup occurs mostly during the intermolt stage.     

Space–time patterns of co‐variation of biodiversity and primary production in phytoplankton guilds of coastal marine environments

• 1. The relevance of biodiversity to ecosystem processes is a major topic in ecology. Here, we analyse the relationship between biodiversity and productivity of the nano‐ and micro‐phytoplankton guilds in coastal marine ecosystems.
• 2. The patterns of variation of species richness, diversity and primary productivity (as ¹⁴C assimilation) were studied in two marine areas: a eutrophic–mesotrophic area beside the River Po delta (northern Adriatic) and an oligotrophic area around the Salento peninsula (southern Adriatic–Ionian). The study was carried out at 23 sites in the northern area and at 45 sites in the southern area. Sites were arranged on expected spatial and temporal gradients of primary productivity variation, according to distance from the coast, optical depths and seasonal period.
• 3. 167 taxa were identified in the northern area and 153 taxa in the southern area. In both areas, the taxonomic composition of the nano‐ and micro‐phytoplankton guilds exhibited greater temporal than spatial variation. The latter was much higher in the southern area than in the northern area (average dissimilarity between stations being 70.7±0.8% and 44.7±4.2% respectively).
• 4. Primary productivity varied in space and time on the gradients considered. Phytoplankton species richness and diversity exhibited significant patterns of variation in space and time; overall, these were inversely related to the primary productivity patterns in the northern area, whereas they were directly related in the southern area.
• 5. The small individual size and the high turnover rate of phytoplankton are likely to underlie the observed relationships, which emphasized a threshold response to nutrient enrichment in agreement with the ‘paradox of enrichment’. Under resource enrichment conditions, the high turnover of producers leads to hierarchical partitioning of the available resources with an increasing dominance of a few species. Therefore, the relationship observed here seems likely to be explained by the complementarity hypothesis.

Copyright © 2003 John Wiley & Sons, Ltd.     

The evolutionary relationship between bere barley and other types of cultivated barley

Genetic Resources and Crop Evolution - We used genotyping-by-sequencing to investigate the evolutionary history of bere, the oldest barley variety still cultivated in Britain and possibly in all of...     

Phosphorus fractions and their availability in the sediments of eight tropical semiarid reservoirs

Journal of Soils and Sediments - We quantified the phosphorus (P) fractions and oxide content in the sediment of eight tropical semiarid reservoirs to assess how water-level decreases affect the...     

Separation of olive proteins combining a simple extraction method and a selective capillary electrophoresis (CE) approach: application to raw and table olive samples

A simple extraction method was developed to extract proteins from olive samples based on chloroform/methanol extraction followed by a protein precipitation with cold acetone. Then, a capillary electrophoresis (CE) method was carried out using an acid buffer (1 M formic acid at pH 2) to ensure a positive net charge for proteins and a neutral charge for potential interferents as polyphenols. The method developed was applied to raw and table olive samples. Interestingly, raw olive samples showed differences in protein profiles depending upon the botanical variety of olives and their geographical region. Protein profiles obtained for table olives also showed differences according to the sample treatment. Thus, a signal reduction in the electropherograms obtained for black olives was observed in comparison to those achieved for treated green olives. In this work, the use of protein profiles was demonstrated to be a powerful tool for studying variations among olive samples.     

Definition of priority areas for forest conservation through the ordered weighted averaging method

The general objective of this study was to evaluate the ordered weighted averaging (OWA) method, integrated to a geographic information systems (GIS), in the definition of priority areas for forest conservation in a Brazilian river basin, aiming at to increase the regional biodiversity. We demonstrated how one could obtain a range of alternatives by applying OWA, including the one obtained by the weighted linear combination method and, also the use of the analytic hierarchy process (AHP) to structure the decision problem and to assign the importance to each criterion. The criteria considered important to this study were: proximity to forest patches; proximity among forest patches with larger core area; proximity to surface water; distance from roads; distance from urban areas; and vulnerability to erosion. OWA requires two sets of criteria weights: the weights of relative criterion importance and the order weights. Thus, Participatory Technique was used to define the criteria set and the criterion importance (based in AHP). In order to obtain the second set of weights we considered the influence of each criterion, as well as the importance of each one, on this decision-making process. The sensitivity analysis indicated coherence among the criterion importance weights, the order weights, and the solution. According to this analysis, only the proximity to surface water criterion is not important to identify priority areas for forest conservation. Finally, we can highlight that the OWA method is flexible, easy to be implemented and, mainly, it facilitates a better understanding of the alternative land-use suitability patterns.     

Horse resistance to natural infestations of Anocentor nitens and Amblyomma cajennense (Acari: Ixodidae).

The objective of this study was to investigate some aspects of horse resistance to natural infestations of Anocentor nitens and Amblyomma cajennense over a 2-year period. Free-living stages of A. nitens were used to evaluate the influence of season of the year on horse resistance. Every 2 weeks, 10 selected engorged females, weighing 150-329 mg, were removed from naturally infested horses and were individually placed into glass tubes closed with a cotton stopper, and maintained in an incubator. The biological parameters evaluated varied according to the season of the year, i.e., reproductive efficiency, maximum larval survival (MLS) and egg-hatching rates were significantly lower in spring/summer than in fall/winter. At 14-day intervals, females of A. nitens and A. cajennense were counted on each side of the body of five mares. A comparison between the animal with the lowest infestation and the animal with the highest infestation showed greater differences in animals infested with A. nitens than those infested with A. cajennense. Ten animals were found to carry 64.9% of the total parasite burden of A. cajennense and 88.6% of the highest infestations of A. nitens females. A seasonal variation on intensity of horse resistance to A. nitens was observed during the study. However, this was not observed for A. cajennense. Cross-resistance was observed in animals with the highest total number of A. cajennense and the highest number of A. cajennense adults (r=0.817), larvae (r=0.756), and A. nitens females (r=0.799). These results led to the conclusion that changes in horse resistance to A. nitens occur seasonally. As far as the total population of A. cajennense and the female stage of A. nitens are concerned, horses develop cross-resistance.     

Experimental colonization of piglets and gilts with systemic strains of Haemophilus parasuis and Streptococcus suis to prevent disease.

Haemophilus parasuis and Streptococcus suis are both major causes of losses during the nursery period, especially in herds using the segregated early weaning system. In this system, only a few piglets may be colonized with the herd's prevalent systemic strain, which results in infection of naive penmates late in the nursery. In view of these factors, the objectives of this study were: (1) to evaluate the early colonization of piglets with the farm's prevalent systemic strain of H. parasuis and S. suis as an alternative method for disease prevention; and (2) to evaluate 2 different protocols for experimental colonization: direct colonization of piglets and colonization of piglets through nose-to-nose contact with inoculated sows. Haemophilus parasuis and S. suis isolates recovered from diseased nursery pigs were characterized by the rep-PCR technique and the herd's prevalent strains were used for colonization. Piglets in the experimentally colonized groups were inoculated at 5 days of age by the oral route using a spray pump. Sows were colonized at 2 weeks prior to farrowing using a similar protocol. Although both colonization protocols were successful in getting the piglets colonized, direct inoculation of 5-day-old piglets with the herd's systemic strains of H. parasuis and S. suis tended to be more effective in reducing the morbidity and the mortality than the colonization of piglets by nose-to-nose contact with inoculated sows.