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131.
Mauricio Cantor Leonardo L. Wedekin Fábio G. Daura‐Jorge Marcos R. Rossi‐Santos Paulo C. Simões‐Lopes 《Marine Mammal Science》2012,28(1):63-83
This study represents the first attempt to study the population dynamics of Guiana dolphins (Sotalia guianensis), by evaluating a set of demographic parameters. The population of the Caravelas River estuary, eastern Brazil, was systematically monitored through a long‐term mark‐recapture experiment (2002–2009). Abundance estimates revealed a small population (57–124 dolphins), comprised of resident dolphins and individuals that temporarily leave or pass through the study area. Temporary emigration from the estuary to adjacencies (γ″= 0.33 ± 0.07 SE) and return rate (1 ?γ′= 0 .67) were moderate and constant, indicating that some dolphins use larger areas. Survival rate (?= 0.88 ± 0.07 SE) and abundance were constant throughout the study period. Power analysis showed that the current monitoring effort has high probability of detecting abrupt population declines (1 ?β= 0.9). Although the monitoring is not yet sensitive to subtle population trends, sufficient time to identify them is feasible (additional 3 yr). Despite such apparent stability, this population, as many others, inhabits waters exposed to multiple human‐related threats. Open and closed population modeling applied to photo‐identification data provide a robust baseline for estimating several demographic parameters and can be applied to other populations to allow further comparisons. Such synergistic efforts will allow a reliable definition of conservation status of this species. 相似文献
132.
Archival bottom‐mounted audio recorders were deployed in nine different areas of the western Mediterranean Sea, Strait of Gibraltar, and adjacent North Atlantic waters during 2006–2009 to study fin whale (Balaenoptera physalus) seasonal presence and population structure. Analysis of 29,822 recording hours revealed typical long, patterned sequences of 20 Hz notes (here called “song”), back‐beats, 135–140 Hz notes, and downsweeps. Acoustic parameters (internote interval, note duration, frequency range, center and peak frequencies) were statistically compared among songs and song notes recorded in all areas. Fin whale singers producing songs attributable to the northeastern North Atlantic subpopulation were detected crossing the Strait of Gibraltar and wintering in the southwestern Mediterranean Sea (Alboran basin), while songs attributed to the Mediterranean were detected in the northwest Mediterranean basin. These results suggest that the northeastern North Atlantic fin whale distribution extends into the southwest Mediterranean basin, and spatial and temporal overlap may exist between this subpopulation and the Mediterranean subpopulation. This new interpretation of the fin whale population structure in the western Mediterranean Sea has important ecological and conservation implications. The conventionally accepted distribution ranges of northeastern North Atlantic and Mediterranean fin whale subpopulations should be reconsidered in light of the results from this study. 相似文献
133.
《Free radical research》2013,47(1-2):7-18
Generation and reactivity of superoxide (02?) and hydroxyl (OH') radicals in enzymatic and radiolytic systems were investigated over the temperature range from 20o-50oC. The generation rate and reaction kinetics of both enzymatically and radiolytically produced superoxide radicals were determined by a cytochrome c reduction assay. For OH' radical reaction studies the degradation of hyaluronic acid was assayed. An increase in temperature leads to a greater reactivity of both radicals, but in the case of an enzymatic source a disproportionate increase in the rate of generation is observed. In the pulse radiolysis system, the reactivity of superoxide radicals was found to be stimulated 15-fold over the temperature range from 20oC to 60oC, although the activity of superoxide dismutase was only minimally increased (about 1.6-fold). The results are discussed with respect to the possible importance of active oxygen species to the biological effects of hyperthermia. 相似文献
134.
Morimoto T Kojima Y Toki T Komeda Y Yoshiyama M Kimura K Nirasawa K Kadowaki T 《Ecology and evolution》2011,1(2):201-217
The honey bee is a major insect used for pollination of many commercial crops worldwide. Although the use of honey bees for pollination can disrupt the habitat, the effects on their physiology have never been determined. Recently, honey bee colonies have often collapsed when introduced in greenhouses for pollination in Japan. Thus, suppressing colony collapses and maintaining the number of worker bees in the colonies is essential for successful long-term pollination in greenhouses and recycling of honey bee colonies. To understand the physiological states of honey bees used for long-term pollination in greenhouses, we characterized their gene expression profiles by microarray. We found that the greenhouse environment changes the gene expression profiles and induces immune-suppression and oxidative stress in honey bees. In fact, the increase of the number of Nosema microsporidia and protein carbonyl content was observed in honey bees during pollination in greenhouses. Thus, honey bee colonies are likely to collapse during pollination in greenhouses when heavily infested with pathogens. Degradation of honey bee habitat by changing the outside environment of the colony, during pollination services for example, imposes negative impacts on honey bees. Thus, worldwide use of honey bees for crop pollination in general could be one of reasons for the decline of managed honey bee colonies. 相似文献
135.
136.
The pathway for the aerobic catabolism of 1,3,5-trihydroxybenzene (phloroglucinol) by a new strain of Penicillium was investigated using both in vivo and in vitro cell-free systems. The fungal strain was isolated by enrichment on phloroglucinol and identified as P. simplicissimum (Oud) Thom. It grew optimally at pH 5.5 and 27°C with 119 mM (1.5%w/v) of phloroglucinol in a basal mineral salts medium. Vapours of the crystalline substrate placed in a Petri-plate lid supported the growth of the fungal colonies on the agar surface. Mycelia grown on phloroglucinol accumulated 1,2,4-trihydroxybenzene and resorcinol in the medium. Washed, resting mycelia grown on phloroglucinol, when resuspended in a buffer utilized oxygen in the presence of catechol, resorcinol, pyrogallol and phloroglucinol. A NADPH-dependent reductase in the cell-free extract reduced phloroglucinol to dihydrophloroglucinol. This electron donor could not be replaced by NADH. Resorcinol hydroxylase, phloroglucinol reductase, catechol-1,2-oxygenase, and catechol-2,3-oxygenase were detected in cell-free extracts of mycelia grown on phloroglucinol. The possible steps in the degradation of phloroglucinol are discussed. 相似文献
137.
Assessments of plant population dynamics in space and time have depended on dated records of fossil pollen synthesized on a subcontinental scale. Genetic analyses of extant populations have revealed spatial relationships that are indicative of past spatial dynamics, but lack an explicit timescale. Synthesis of these data requires genetic analyses from abundant dated fossil material, and this has hitherto been lacking. Fossil pollen is the most abundant material with which to fill this data gap. Here we report genetic analyses of fossil pollen retrieved from Holtjärnen postglacial lake sediment in Sweden and show that plastid DNA is recoverable from Scots Pine and Norway spruce pollen grains that are 100 and 10 000 years old. By sequencing clones from two short plastid PCR products and by using multiple controls we show that the ancient sequences were endogenous to the fossil grains. Comparison of ancient sequences and those obtained from an extant population of Scots pine establishes the first genetic link between extant and fossil samples in this species, providing genetic continuity through time. The finding of one common haplotype present in modern, 100-year old and 10 000-year old samples suggests that it may have persisted near Holtjärnen throughout the postglacial period. This retrieval of ancient DNA from pollen has major implications for plant palaeoecology in conifer species by allowing direct estimates of population dynamics in space and time. 相似文献
138.
陕南茶树栽培区域生态与地方品种分布 总被引:1,自引:0,他引:1
陕南秦巴山区是亚热带北缘地区。由于生态环境复杂,地区差异性大,茶树栽培与引种受到一定限制。大致以汉江谷地粮作区为界,南部大巴山北麓低山丘陵区为适栽区;北部秦岭南麓低山丘陵区则为次适栽区。地方茶树群体品种有7个,约由28个地方品种组成,呈斑、块状分布。 相似文献
139.
Alison Shapcott Heather James Laura Simmons Yoko Shimizu Lauren Gardiner David Rabehevitra Rokiman Letsara Stuart Cable John Dransfield William J. Baker Mijoro Rakotoarinivo 《Ecology and evolution》2020,10(6):3120-3137
Madagascar is home to 208 indigenous palm species, almost all of them endemic and >80% of which are endangered. We undertook complete population census and sampling for genetic analysis of a relatively recently discovered giant fan palm, the Critically Endangered Tahina spectablis in 2008 and 2016. Our 2016 study included newly discovered populations and added to our genetic study. We incorporated these new populations into species distribution niche model (SDM) and projected these onto maps of the region. We developed population matrix models based on observed demographic data to model population change and predict the species vulnerability to extinction by undertaking population viability analysis (PVA). We investigated the potential conservation value of reintroduced planted populations within the species potential suitable habitat. We found that the population studied in 2008 had grown in size due to seedling regeneration but had declined in the number of reproductively mature plants, and we were able to estimate that the species reproduces and dies after approximately 70 years. Our models suggest that if the habitat where it resides continues to be protected the species is unlikely to go extinct due to inherent population decline and that it will likely experience significant population growth after approximately 80 years due to the reproductive and life cycle attributes of the species. The newly discovered populations contain more genetic diversity than the first discovered southern population which is genetically depauperate. The species appears to demonstrate a pattern of dispersal leading to isolated founder plants which may eventually lead to population development depending on local establishment opportunities. The conservation efforts currently put in place including the reintroduction of plants within the species potential suitable habitat if maintained are thought likely to enable the species to sustain itself but it remains vulnerable to anthropogenic impacts. 相似文献
140.
Yoshiko Kono Kuo-Fang Chung Chih-Hui Chen Yoshikazu Hoshi Hiroaki Setoguchi Chang-Hung Chou Kazuo Oginuma Ching-I Peng 《Annals of botany》2012,110(6):1119-1135