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Subsequent Seasons (subsequent + season)
Selected AbstractsBENTHIC AND PLANKTONIC ALGAL COMMUNITIES IN A HIGH ARCTIC LAKE: PIGMENT STRUCTURE AND CONTRASTING RESPONSES TO NUTRIENT ENRICHMENT,JOURNAL OF PHYCOLOGY, Issue 6 2005Sylvia Bonilla We investigated the fine pigment structure and composition of phytoplankton and benthic cyanobacterial mats in Ward Hunt Lake at the northern limit of High Arctic Canada and the responses of these two communities to in situ nutrient enrichment. The HPLC analyses showed that more than 98% of the total pigment stocks occurred in the benthos. The phytoplankton contained Chrysophyceae, low concentrations of other protists and Cyanobacteria (notably picocyanobacteria), and the accessory pigments chl c2, fucoxanthin, diadinoxanthin, violaxanthin, and zeaxanthin. The benthic community contained the accessory pigments chl b, chl c2, and a set of carotenoids dominated by glycosidic xanthophylls, characteristic of filamentous cyanobacteria. The black surface layer of the mats was rich in the UV-screening compounds scytonemin, red scytonemin-like, and mycosporine-like amino acids, and the blue-green basal stratum contained high concentrations of light-harvesting pigments. In a first bioassay of the benthic mats, there was no significant photosynthetic or growth response to inorganic carbon or full nutrient enrichment over 15 days. This bioassay was repeated with increased replication and HPLC analysis in a subsequent season, and the results confirmed the lack of significant response to added nutrients. In contrast, the phytoplankton in samples from the overlying water column responded strongly to enrichment, and chl a biomass increased by a factor of 19.2 over 2 weeks. These results underscore the divergent ecophysiology of benthic versus planktonic communities in extreme latitudes and show that cold lake ecosystems can be dominated by benthic phototrophs that are nutrient sufficient despite their ultraoligotrophic overlying waters. [source] Breeding success in Blue Tits: good territories or good parents?JOURNAL OF AVIAN BIOLOGY, Issue 3 2001Robert Przybylo Territorial quality and parental quality are usually assumed to be the main sources of variation in the reproductive success of passerine birds. To evaluate their relative importance for variation in breeding time (itself an important factor for breeding success), clutch size and offspring condition at fledging, we analysed six years of data from a Blue Tit Parus caeruleus population breeding on the island of Gotland, Sweden. Hatching dates and the condition of offspring were consistent for territories between years and accounted for 30% and 33% of the variation in these variables, respectively. After removing the effect of territory quality, none of the breeding parameters were significantly repeatable for individual females, but offspring condition was repeatable for males, accounting for 28% of variation. For females breeding on the same territory in subsequent seasons (combined effect of individual and territory quality) only hatching date was repeatable (45% of variation accounted for). In males, the combined effect of individual and territory quality was repeatable for offspring condition and accounted for 33% of variation, but this result was only marginally significant. Consistency of the peak frass-fall date for individual frass collectors over the study period suggests that repeatable hatching dates on territories may be related to the relationship between timing of breeding and timing of peak food availability on territories. Our results suggest that territory quality is more important than parental quality for breeding success in the Blue Tit, and that male (but not female) quality makes a considerable contribution to reproductive success. [source] A RESIDENT POPULATION OF INDO-PACIFIC BOTTLENOSE DOLPHINS (TURSIOPS ADUNCUS) IN AMAKUSA, WESTERN KYUSHU, JAPANMARINE MAMMAL SCIENCE, Issue 1 2002Miki Shirakihara Abstract Residency patterns and population size were examined for Indo-Pacific bottlenose dolphins (Tursiops aduncus) in the coastal waters of Amakusa-Shimoshima Island, western Kyushu, Japan, from summer 1994 to fall 1998. A total of 203 individuals were identified. The number of newly identified individuals barely increased after the first 1.5 yr. The identified individuals in one season were frequently resighted with percentages of mostly over 60% during the subsequent seasons. Most of the dolphins off Amakusa were yearround residents, although the total range of their habitat was unknown. The population size estimated by the mark-recapture technique was 218 individuals with a CV of 5.41% in 1995,1997. The group commonly consisted of more than 100 individuals. The large group size was thought to be a response to feeding on schooling fishes. [source] Control of woolly aphid, Eriosoma lanigerum (Hausmann) (Hemiptera: Pemphigidae) on mature apple trees using insecticide soil-root drenchesAUSTRALIAN JOURNAL OF ENTOMOLOGY, Issue 1 2003Adrian H Nicholas Abstract Woolly aphid, Eriosoma lanigerum, is an important pest of apples that infests both the aerial and root parts of the tree. Root colonies are protected from the pesticide sprays applied during the growing season and the climatic effects of winter. Consequently, root colonies are a major source of aerial re-infestation in the following spring. Imidacloprid, the first of a new group of insecticides from the chloronicotinyl family, is known to provide excellent control of woolly aphid on trees up to 7-years-old when applied as a root soil drench. This study compared the effects of a single application of chlorpyrifos, imidacloprid, pirimicarb or vamidothion, applied as a root drench over four growing seasons. A soil wetting agent was added to each chemical to improve soil saturation and penetration. Imidacloprid provided excellent control of woolly aphid on the trees that were 17-years-old at the start of the study and continued to do so for four seasons. Pirimicarb appeared to offer some suppression of woolly aphid during the first season but not in subsequent seasons, while chlorpyrifos and vamidothion failed to control woolly aphid in any season. The potential role for imidacloprid in IPM programs is discussed. [source] Repeatability of size and fluctuating asymmetry of antler characteristics in red deer (Cervus elaphus) during ontogenyBIOLOGICAL JOURNAL OF THE LINNEAN SOCIETY, Issue 2 2007L. BARTO Fluctuating asymmetry (FA) has been suggested as a measure of the sensitivity of development to a wide array of genetic and environmental stresses. It has been also suggested that antlers in red deer could be important during social and rutting displays. We used antler measurements of 51 males that were measured over subsequent seasons, from 3,8 years of age, and analysed three antler traits: antler weight, length, and the number of antler tines (antler size). We calculated absolute and relative FA. All three size traits were highly significantly intercorrelated. By contrast to this, the FA of the three traits, did not show such relationships. With increasing age, antler size and FA also increased. When testing the repeatability of FA and antler size, there was a principal difference in the pattern between FA and antler size, with the latter being much more consistent than the former. This suggests that antler size, not FA, may be a good predictor of the bearer's quality in mate selection. This fits well with the good-genes hypothesis that the development of extravagant secondary sexual characters can be an honest advertisement of heritable male quality. © 2007 The Linnean Society of London, Biological Journal of the Linnean Society, 2007, 91, 215,226. [source] | ||||||||||