The potential impact of increasing vessel traffic and coastal development has led to concerns regarding the future of the Brazilian humpback whale Megaptera novaeangliae population. Our objective was to monitor humpback whale abundance in the Brazilian coastal breeding grounds in order to provide information to support future conservation strategies for this species. To this end, a 4 yr series (2002 to 2005) of aerial surveys was implemented. Abundance was estimated using standard line-transect methods. Data were analyzed using the software DISTANCE 5.0. Perpendicular sighting data were modeled using (1) the uniform function with cosine and simple polynomial adjustments, (2) the half-normal function with cosine, and (3) the hazard-rate function with cosine and a simple polynomial series expansion. The model that best fitted the data was selected according to Akaike's Information Criterion (AIC). We estimated the population off the Brazilian coast to be 6404 (CV = 0.11) ind. in 2005. Alternative scenarios are presented to permit the discussion of results obtained from different g (0) corrections (where g (0) is the probability of detecting an animal at distance 0). We confirmed what previous studies have shown, i.e. that the studied population is increasing, and it is expected that new areas will be occupied and conflicts of interests will arise. The results of this study support the Brazilian government's stance against whaling and should be used in national and international debate to help solve conflicts of interest and to find non-lethal solutions.
The waters surrounding Abrolhos Archipelago, Brazil, serve as one of several winter grounds for southern-hemisphere humpback whales (Megaptera novaeangliae). Development of tourism in this region has caused concern over disturbance effects to breeding and nursing whales. To document the chronology of humpback abundance around Abrolhos, three years of visualscan data obtained during July through November 1998-2000 were analyzed. During 1-hour scans, observers visually tracked all groups within 9.3km and nearly 360° around a land-based theodolite station to determine group size, composition and behavior. Including only groups of known size, hourly counts (n=462) of adult and calf humpback whales ranged from 0-31 and 0-9, respectively. Group size could not be determined for 255 of 2146 groups observed. Humpback whale abundance was seasonal: there were few in early July when surveys began, peaked in early September, and then gradually declined to zero by late November. Based on Poisson regression, the annual chronology of whale occupancy was relatively invariant. Peak counts averaged about 15 adult whales per hour. Although no evidence was found that the timing of peak counts varied, peak abundance varied among years, and more whales were seen during morning than afternoon. The mean number of adults per group did not vary over time (year, day of year, or time of day), but the likelihood of group size being indeterminate varied predictably. Thus, indices of abundance could be adjusted by assuming that the size of indeterminate groups equals mean group size. Calf abundance varied with adult abundance, and the proportion of groups with calves increased from July through November. The high frequency of groups containing a calf (49.8%) within 9.3km of the Abrolhos Archipelago demonstrated the importance of this area for calves, and proper management is recommended.Resumo As águas ao redor do Arquipélago dos Abrolhos, Brasil, são uma das muitas áreas de inverno para as baleias jubarte (Megaptera novaeangliae) no hemisfério sul. O desenvolvimento do turismo nessa região e seus efeitos nas atividades de reprodução e cria das baleias, causam preocupação. Para documentar a abundância cronológica de baleias jubarte ao redor de Abrolhos, foram analisados três anos de dados obtidos a partir de varredura visual entre julho e novembro de 1998 a 2000. Durante varreduras de uma hora, observadores acompanharam visualmente todos os grupos de baleias presentes em 9,3km e aproximadamente 360° em torno de um ponto fixo equipado com teodolito, para determinar tamanho, composição e comportamento dos grupos. Incluindo somente grupos com tamanho conhecido, as contagens de adultos e filhotes nas varreduras (n=462) variaram entre 0-31 e 0-9 respectivamente. O tamanho de grupo não pôde ser determinado em 255 dos 2146 grupos observados. A abundância foi sazonal: havia poucas baleias no início de julho quando as observações iniciaram, atingindo o pico no início de setembro e decaindo gradativamente até zero no final de novembro. Baseado ...
Cyclocephline scarabs and their host plants are documented as highly specialized plant-pollinator associations, with various fine-tuned adaptations. We studied the association between Philodendron adamantinum, a species endemic to the Espinhaço Range in Minas Gerais, South-East Brazil, and its exclusive pollinators. We focused on the pollination mechanism and reproductive success of P. adamantinum, analysed its floral scent composition, and performed field bioassays to verify the scent-mediated attraction of pollinators. The reproductive success of P. adamantinum depends on the presence of Erioscelis emarginata (Scarabaeidae, Cyclocephalini), its sole pollinator. At dusk, the inflorescences heat up to 18°C above the surrounding ambient air temperature and give off a strong sweet odour, from which 32 volatile compounds were isolated. Dihydro-β-ionone, the major constituent in the floral scent bouquet, lures individuals of E. emarginata when applied to scented artificial decoys, either alone or blended with methyl jasmonate. We attribute the low fruit set of P. adamantinum at our study sites to pollinator limitation of small and isolated populations and geitonogamic pollen flow of vegetatively generated clonal plant groups. The interaction between P. adamantinum and E. emarginata shows common traits typical of the known plant-pollinator associations involving cyclocephaline scarabs: the asymmetrical dependence of plants on their pollinators, and the scent-mediated interaction between flowers and beetles. In addition to updating the current catalogue of active compounds of cantharophilous pollination systems, further experimental studies should elucidate the role of the specific chemical compounds that attract pollinators along different time and biogeographic scales.
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