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CHRISTINE REBER FUNK REGULA SCHMID‐HEMPEL PAUL SCHMID‐HEMPEL 《Molecular ecology resources》2006,6(1):83-86
We report the details and characteristics of a total of 44 novel microsatelllite loci for Bombus spp. Most of them are highly polymorphic in Bombus terrestris, and a high degree of polymorphism is also found where these primers have been tested in 10 other bumblebee species. These markers will therefore be useful for the genetic study of this group. 相似文献
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Separating the effects of climate and vegetation on evapotranspiration along a successional chronosequence in the southeastern US 总被引:3,自引:0,他引:3
PAUL C. STOY GABRIEL G. KATUL MARIO B. S. SIQUEIRA JEHN-YIH JUANG KIMBERLY A. NOVICK HEATHER R. McCARTHY A. CHRISTOPHER OISHI JOSHUA M. UEBELHERR HYUN-SEOK KIM RAM OREN 《Global Change Biology》2006,12(11):2115-2135
We combined Eddy‐covariance measurements with a linear perturbation analysis to isolate the relative contribution of physical and biological drivers on evapotranspiration (ET) in three ecosystems representing two end‐members and an intermediate stage of a successional gradient in the southeastern US (SE). The study ecosystems, an abandoned agricultural field [old field (OF)], an early successional planted pine forest (PP), and a late‐successional hardwood forest (HW), exhibited differential sensitivity to the wide range of climatic and hydrologic conditions encountered over the 4‐year measurement period, which included mild and severe droughts and an ice storm. ET and modeled transpiration differed by as much as 190 and 270 mm yr?1, respectively, between years for a given ecosystem. Soil water supply, rather than atmospheric demand, was the principal external driver of interannual ET differences. ET at OF was sensitive to climatic variability, and results showed that decreased leaf area index (L) under mild and severe drought conditions reduced growing season (GS) ET (ETGS) by ca. 80 mm compared with a year with normal precipitation. Under wet conditions, higher intrinsic stomatal conductance (gs) increased ETGS by 50 mm. ET at PP was generally larger than the other ecosystems and was highly sensitive to climate; a 50 mm decrease in ETGS due to the loss of L from an ice storm equaled the increase in ET from high precipitation during a wet year. In contrast, ET at HW was relatively insensitive to climatic variability. Results suggest that recent management trends toward increasing the land‐cover area of PP‐type ecosystems in the SE may increase the sensitivity of ET to climatic variability. 相似文献
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CHRISTIAN E. W. STEINBERG SHEKU KAMARA VALERIA YU. PROKHOTSKAYA LEVONAS MANUSADIANAS TATYANA A. KARASYOVA MAXIM A. TIMOFEYEV ZHANG JIE REA PAUL THOMAS MEINELT VINICIUS F. FARJALLA ALINE Y. O. MATSUO B. KENT BURNISON RALPH MENZEL 《Freshwater Biology》2006,51(7):1189-1210
1. This review focuses on direct and indirect interactions between dissolved humic substances (HS) and freshwater organisms and presents novel opinions and hypotheses on their ecological significance. Despite their abundance in freshwaters, the role of HS is still inadequately understood. These substances have been considered too large to be taken up by freshwater organisms. On the contrary, here we present evidence that dissolved HS are indeed taken up and interact directly and/or indirectly with freshwater organisms. 2. We show that dissolved HS exert a mild chemical stress upon aquatic organisms in many ways; they induce molecular chaperones (stress shock proteins), induce and modulate biotransformation enzymes and modulate (mainly inhibiting) the photosynthetic release of oxygen by freshwater plants. Furthermore, they produce an oxidative stress, which may lead to membrane oxidation. HS modulate the multixenobiotic resistance activity and probably other membrane‐bound pumps. This property may lead to the increased bioaccumulation of xenobiotic chemicals. Furthermore, they can modulate the numbers of offspring in a nematode and feminise fish and amphibians. The ecological consequences of this potential remain obscure at present. HS also have the potential to act as chemical attractants (as shown with a nematode). 3. In some macrophytes and algae we show that HS interfere with photosynthesis and growth. For instance, the presence of HS suppresses cyanobacteria more than eukaryotic algae. By applying a quantitative structure activity relationship approach, we show that quinones in the HS interfere with photosynthetic electron transport. We show that even Phragmites leachate can act as a kind of phytotoxin. HS also have the potential to suppress fungal growth, as shown with the water mould Saprolegnia parasitica and force the fungus to respond by spore production. 4. In very soft, humic freshwaters, such as the Rio Negro, Brazil, HS stimulate the uptake of essential ions, such as Na and Ca, at extremely low pH (3.5–4.0) and prevent the ionoregulatory disturbance induced by acid waters, thereby enabling fish to survive in these environments. 5. We discuss whether or not HS are directly utilised by aquatic microorganisms or via exoenzymes, which may be washed in from the terrestrial catchment. There is accumulating evidence that the quality of the HS controls microbial growth. In total, net‐heterotrophy may result from HS‐mediated suppression of primary production by the quinone structures and/or from HS‐mediated support of microbial growth. As there is also evidence that HS have the potential to support photoautotrophic growth and suppress microbial growth, the opposite community effect could result. Consequently, dissolved organic carbon (DOC) has to be chemically characterised, rather than simply measuring bulk DOC concentration. 6. In sum, dissolved HS interact with freshwater organisms in a variety of ways in unenriched humic lakes. In addition to the well known effects of HS on light regime, for example, and the direct and indirect supply with carbon (energy), other interactions may be much more subtle. For instance, HS may induce internal biochemical stress defence systems and have the potential to cause acclimatisation and even adaptation. We are just at the beginning of understanding these interactions between dissolved HS and freshwater organisms. 相似文献
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Abstract To characterize the structure and species density of termite assemblages in tropical forests, we developed a sampling protocol based on a single large quadrat (belt transect) that standardises sampling effort and area. Emphasizing the estimation of species richness, Roisin and Leponce (2004, Austral Ecology, 29 : 637–46) recommend sampling numerous small quadrats, and varying the number of quadrats depending on local species density. However, their method would result in the loss of standardisation and speed, taking up to four times longer to collect and process the samples. We show that even for a subtropical forest with low species density, our protocol produces robust results. 相似文献
89.
Detecting and predicting how populations respond to environmental variability are eminent challenges in conservation research and management. This is particularly true for wildlife populations at high latitudes, many of which demonstrate changes in population dynamics associated with global warming. The Falkland Islands (Southwest Atlantic) hold one of the largest Gentoo Penguin Pygoscelis papua populations in the world, representing c. 34% of the global population. The numbers of breeding Gentoo Penguins at the Falkland Islands have shown a high degree of inter‐annual variability since monitoring commenced in 1990. However, proximate causes of annual variability in breeding numbers have not been explored. Here we examine 21 years of Gentoo Penguin breeding surveys from the Falkland Islands and assess whether inter‐annual variability in the number of breeding pairs were correlated with proxies of environmental variability. There was a positive correlation between the number of breeding pairs and a broad‐scale climatic variation index, the Southern Oscillation Index (SOI). In turn, the SOI was significantly correlated with spring sea surface temperature anomalies, indicating a more immediate atmospherically forced response to El Niño Southern Oscillation variability in the Southwest Atlantic than previously reported. However, we also describe a non‐linear response to environmental variability that may highlight foraging plasticity and/or the complexity of regional ecosystem interactions that operate across a range of different scales. 相似文献
90.
KOH NAKAMURA TETSUO DENDA GORO KOKUBUGATA PAUL I. FORSTER GARY WILSON CHING‐I PENG MASATSUGU YOKOTA 《Biological journal of the Linnean Society. Linnean Society of London》2012,105(1):197-217
An antitropical distribution represents an intriguing disjunction, in which a given species or sister lineages occupy regions north and south of the tropics but are absent from the intervening areas. Solenogyne mikadoi endemic to the Ryukyu Archipelago is regarded as an Australian element. Testing the phylogenetic relationship with Australian congeners and discussing the onset timing and causes of the disjunction would potentially enhance the understanding of antitropical distribution. A nuclear ribosomal DNA phylogeny was reconstructed using Bayesian and most parsimonious criteria with allied genera. Solenogyne was monophyletic and clustered with Lagenophora huegelii endemic to Australia, indicating the antitropical distribution and Australian origin of Solenogyne. Multispecies coalescent analysis based on nuclear ribosomal DNA and chloroplast DNA indicated the divergence of S. mikadoi and Australian congeners in the Plio‐Pleistocene. Phylogenetic network analyses suggested that the ancestral lineage of S. mikadoi first colonized the southernmost island in the archipelago and then dispersed northward. The migration to the archipelago likely followed the flourishing of Solenogyne in open vegetation communities that radiated in south‐eastern Australia during the late Pliocene. This disjunction might arise through long‐distance dispersal across the tropics or, alternatively, through extinction in the tropics as a result of unsuitably high temperatures during climate oscillation and/or competitions from diverse tropical flora surviving since the early Tertiary. © 2011 The Linnean Society of London, Biological Journal of the Linnean Society, 2012, 105 , 197–217. 相似文献