Genetic diversity and historical biogeography of the Maltese wall lizard,Podarcis filfolensis (Squamata: Lacertidae)

Podarcis filfolensis is an endemic lizard from the Maltese archipelago. There is evidence of human-mediated decline and even extirpation of some insular populations of this species. However, information about the intraspecific genetic diversity and phylogeographic patterns of this species is limited. Here we analyze genetic markers from a multi-locus dataset (mtDNA, 2,533 bp; nuclear c-mos gene, 353 bp; 11 microsatellites) for individuals from extant populations of P. filfolensis. Despite generally low genetic variability, two main mitochondrial groupings were clearly identified. In general, individuals from the main island of Malta were genetically distinct from those from Gozo, Comino, Cominotto and Small Blue Lagoon Rock, and also from Linosa and Lampione individuals. Three genetic clusters were detected based on microsatellite data: one was found at higher frequency on Malta, while the other two included samples from the remaining islands, showing some concordance with the mtDNA pattern. A time-calibrated Bayesian tree for the principal mitochondrial lineages indicated strong statistical support for two P. filfolensis lineages that originated in the Pleistocene (105.4–869 Ka). We show that these lineages largely meet the criteria for recognition as evolutionary significant units despite some recent admixture (possibly due to recent translocations between islands). Human disturbance, low genetic variability, evidence of bottlenecks and extirpation on one island indicate that a thorough review of the current conservation status of P. filfolensis would be timely.     

Genetic variation and differentiation in the lizard, Podarcis wagleriana (Reptilia: Lacertidae)

The electrophoretic variation at 26 presumptive gene loci was investigated in populations of Podarcis ivagleriana from Sicily, the Aegadian Islands, and the Aeolian Islands. For interspecific comparison, samples of the closely related lizard P. sicula from the same geographic area were also used. Population heterogeneity analyses carried out by the estimation of F-statistics and Nei's standard genetic distance, showed a high genetic homogeneity within P. sicula, but a noticeable genetic differentiation within P. wagleriana. In the latter species, Nei's D ranged from 0 to 0.212, and this is because the Aeolian populations were quite distinct from those inhabiting Sicily and the Aegadian Islands. Fixed differences identified at three loci (Ck, Ada, Gp-4) contributed to a relatively high value of Nei's standard genetic distance between the two population groups (D= 0.147). This value is very similar to those found comparing pairs of well-recognized biological species included in the genera Podarcis and Lacerta. Estimation of the time of evolutionary divergence shows that the Aeolian and Sicilian populations of P. wagleriana have been isolated geographically for a long time (0.7 Myr according to Nei's formula; 2 Myr according to Sarich's calibration), indicating evolutionary divergence at the species level. Based on genetic and biogeographic data, it is suggested the recognition of full specific status for the Aeolian populations, for which the name P. rajfonei comb. nova (Aeolian wall lizard) is proposed. Electrophoretic data and comparative species distributions suggest that (1) Podarcis sicula recently colonized the Aeolian Islands, and (2) it has competed successfully with P. rajfonei in this area, greatly reducing the range of the latter and causing the extinction of most of its populations. In fact, P. sicula is widespread in the Aeolian Archipelago, while P. rajfonei is confined at present to one large island (Vulcano) and three tiny islands (Strombolicchio, Scoglio Faraglione, La Canna). This can be considered a classic example of competitive exclusion of a native form (P. rajfonei) by a species accidentally introduced by man (P. sicula).     

Uptake of phosphate from soils and fertilizers as affected by soil P availability and solubility of phosphorus fertilizers

Fertilizers labelled with ³²P were used to measure amounts of phosphorus, P_s and P_F, taken up by Lolium perenne from available soil P and from P fertilizer respectively, when applied at a rate of 66 mg P·(kg soil^–1) in greenhouse experiments. The quantity P_s of phosphorus taken up from soil in the presence of P fertilizer was compared to the quantity P_o taken up from soil without P fertilizer. The quantity (P_s–P_o) is positive for low P_o values, i.e. in soils poor in available phosphorus, but is negative for high P_o values indicating that an input of P fertilizer can induce a decrease in the utilization of available soil phosphorus. Moreover, for a given soil, the quantity (P_s–P_o) depends on the chemical form of the fertilizer. The standard method of evaluation of P fertilizer efficiency is based on the assumption that P_s=P_o, but P_s can differ from P_o. This result can explain the contradictory data published from field experiments about the efficiency of the various P fertilizers.     

Microbial Biomass and Community Composition Involved in Cycling of Organic Phosphorus in Sediments of Lake Dianchi,Southwest China

Organic phosphorus (P_o) was a major fraction of phosphorus (P) in sediments of lakes, and microbes were involved in most of its relevant biogeochemical cycling. Forms and quantification of P_o were investigated by sequential fractionation in 18 sediments of Lake Dianchi, Southwest China. Microbial biomass and community structure in these sediments were determined by phospholipid fatty acids (PLFAs). Distribution of P_o fractions were in the rank order that humic P_o > nucleic acid and polyphosphate > residual P > Ca-Al-P_o > Fe-P_o > sugar P_o > acid soluble P_o > H₂O-P_o. The recoveries of P_o and P_i in these detailed sequential fractions including residual P shows that the total contents of P_o in sediments of lakes were overestimated by the Standards, Measurements and Testing (SMT) protocol (ignition method). Microbial biomass including Gram-positive bacteria (14.4–20.0%), Gram-negative bacteria (32.7–38.4%), microeukaryotes (14.9–24.4%), aerobic bacteria (43.6–55.8%), anaerobic bacteria (0–2.9%) and type ? methanotrophs (17.6–24.4%) were assigned. Microbial mass and their composition were strongly correlated with H₂O-P_o, Fe-P_o, nucleic acid and polyphosphate, and humic P_o, though residual P was likely inert for microbes in sediments. The formation and degradation of P_o was closely related with microbial activities in sediments. These findings have implications for understanding the role of microbes on cycling of P_o and organic matter in sediments of lakes.     

Circadian organization in the ruin lizard Podarcis sicula: the role of the suprachiasmatic nuclei of the hypothalamus

The effects of electrolytic lesions to the suprachiasmatic nuclei of the hypothalamus (SCN) on circadian rhythms of locomotor activity were examined in ruin lizards Podarcis sicula maintained in constant darkness and constant temperature (29°C). All lizards (N=15) in which the lesion damaged 80% or more of the SCN became behaviorally arrhythmic. On the contrary, locomotor rhythms persisted in all cases (N=11) when the SCN remained intact and lesions were confined to neighbouring regions of the preoptic area. Taken together with previous work which demonstrates that the pineal and the retinae are not essential for the persistence of circadian locomotor rhythmicity in Podarcis sicula and with recent evidence showing the homology between the SCN of lizards and those of mammals the present results strongly support the view that the SCN of Podarcis sicula contain the primary pacemaker(s) for locomotor rhythms.Abbreviations DD constant darkness - LL constant light - SCN suprachiasmatic nuclei of the hypothalamus - PH nucleus periventricularis hypothalami - OC optic chiasm - te length of circadian activity - freerunning circadian period     

Iron(III) nitrate complexes with linear pentacoordinate ligands and their base hydrolysis products

The complexes, Fe(saldpt)NO₃, [Fe(salmedpt)]₂(NO₃)(OH), Fe(saldien)NO₃, and Fe(salmedien)NO₃·CH₂Cl₂, have been prepared. Solid state properties (IR spectra, Mössbauer spectra and magnetic moments) and solution properties (electronic spectra, PMR spectra, conductivities and cyclic voltammograms) have been measured. The saldpt and saldien compounds when reacted with aqueous KOH formed Fe(saldpt)sal and Fe(saldien)OC₂H₅·H₂O. Single crystals of Fe(saldpt)sal were prepared and examined. Crystal data: Fe(saldpt)sal: monoclinic, space group P2₁/c(#14), a=12.486(5), b=18.502(8), c=10.870(5) Å, β=104.23(3)°, V=2434(2) ų, Z=4, D_c=1.40 g cm⁻³, R=0.0473 (R_w=0.0681) for 317 parameters and 2107 data with F_o² > 3σ(F_o²).     

Allozyme diversity in pheasants (<Emphasis Type="Italic">Phasianus</Emphasis> spp.) from breeding stations in Serbia

The pheasant breeds are widely used for restocking of natural populations depleted by hunting. The pheasant population number decline was detected during the 1970s in many hunting areas of Europe. One of its possible reasons might be the loss of adaptability in populations originating from breeding stations, which was caused by inbreeding depression. The aim of this paper was the analysis of genetic variability in pheasant populations from three breeding stations in Vojvodina province (Serbia) by means of allozyme diversity detection. The allozyme variability analysis of pheasants from all three breeding stations revealed polymorphisms at nine loci: Ldh-1, Mor-1, Mor-2, Es-1, Mod-2, Pgd, Gpi-2, Odh, and Sod. The analysis of individuals from three different breeding stations showed mean values of observed heterozygosity of H _o=0.137, polymorphism P _95%=30%, and H/P ratio H/P=0.430, which indicate a normal level of genetic variability for bird populations. Comparative analysis of three pheasant populations showed a high level of interpopulation differentiation.     

A monte carlo approach to population dynamics of cells in a HIV immune response model

Summary Using a direct Monte Carlo simulation, population growth of helper T-cells (N _H) and viral cells (N _v) is studied for an immune response model with an enhanced spatial inter-cellular interaction relevant to HIV as a function of viral mutation. In the absence of cellular mobility (P _mob=0), the helper T-cells grow nonmonotonically before reaching saturation and the viral population grows monotonically before reaching a constant equilibrium. Cellular mobility (P _mob=1) enhances the viral growth and reduces the stimulative T-cell growth. Below a mutation threshold (P _c), the steady-state density of helper T-cell (p _H) is larger than that of the Virus (p _v); the density difference Δp _o(=pV−pH) remains a constant at P _mob=1 while −Δp _o→0 as P _mut→P _c at P _mob=0. Above the mutation threshold, the difference Δp _o in cell density, grows with ΔP=P _mut−P _c monotonically: ΔP _o ∞ (ΔP)^β ≃ with β≈0.574±0.016 in absence of mobility, while Δp _o≈6(ΔP) with P _mob=1.     

Vasa protein is localized in the germ cells and in the oocyte-associated pyriform follicle cells during early oogenesis in the lizard <Emphasis Type="Italic">Podarcis sicula</Emphasis>

The vasa gene, first identified in Drosophila, is a key determinant for germline formation in eukaryotes. Homologs of vasa have been identified and linked to germline development, in many invertebrates and vertebrates. Here, we analyze the distribution of Vasa in early germ cells (oogonia and oocytes) and previtellogenic ovarian follicles of the lizard Podarcis sicula. During most of its previtellogenic growth, the oocyte in this lizard species is structurally and functionally integrated through intercellular bridges with special follicle cells called pyriform cells. The pyriform cells function similarly to Drosophila nurse cells, but are somatic in origin. In the oogenesis of P. sicula, Vasa is initially highly detected in the oogonia, but its levels decrease in early stage oocytes before the onset of pyriform cell differentiation. In the later stages of oogenesis, the high level of Vasa is related with the nurse function of the pyriform follicle cells. These observations suggest that cells of somatic origin are engaged in the synthesis of Vasa in the oogenesis of this lizard.     

Patterns of cranial ontogeny in lacertid lizards: morphological and allometric disparity

We explored the ontogenetic dynamics of the morphological and allometric disparity in the cranium shapes of twelve lacertid lizard species. The analysed species (Darevskia praticola, Dinarolacerta mosorensis, Iberolacerta horvathi, Lacerta agilis, L. trilineata, L. viridis, Podarcis erhardii, P. melisellensis, P. muralis, P. sicula, P. taurica and Zootoca vivipara) can be classified into different ecomorphs: terrestrial lizards that inhabit vegetated habitats (habitats with lush or sparse vegetation), saxicolous and shrub‐climbing lizards. We observed that there was an overall increase in the morphological disparity (MD) during the ontogeny of the lacertid lizards. The ventral cranium, which is involved in the mechanics of jaw movement and feeding, showed higher levels of MD, an ontogenetic shift in the morphospace planes and more variable allometric patterns than more conserved dorsal crania. With respect to ecology, the allometric trajectories of the shrub‐climbing species tended to cluster together, whereas the allometric trajectories of the saxicolous species were highly dispersed. Our results indicate that the ontogenetic patterns of morphological and allometric disparity in the lacertid lizards are modified by ecology and functional constraints and that the identical mechanisms that lead to intraspecific morphological variation also produce morphological divergence at higher taxonomic levels.     

The structure and properties of tetrakis(tironato)cerate(IV), Na12[Ce(C6H2O2(SO3)2)4]·9H2O·6C3H7NO

The title complex, prepared in 1 M NaOH, was crystallized from hot N,N-dimethylformamide/ ethanol solutions to give Na₁₂[Ce(C₆H₂O₂(SO₃)₂)₄]· 9H₂O·6DMF. The purple—brown crystals were examined by X-ray diffraction while inside quartz capillaries filled with DMF, (λ_max 425 nm, ϵ 3664; λ_sh 520 nm, ϵ 2240) and belong to space group Pbca, Z=8 with a=21.846(4), b=17.348(2), c=43.103- (6) Å, V=16.335(7) ų, D_c=1.693 gcm^t−3, D_o=1.725 g cm^t−3. Diffractometer data were collected using Mo Kα radiation to 2θ=43^o. For 7331 independent data with F_o²>3σ(F_o²) full matrix least squares refinement converged to unweighted and weighted R factors of 0.072 and 0.110, respectively, with a mixture of anisotropic and isotropic thermal parameters. The disordered DMF atom parameters were not refined. The structure consists of discrete monomeric Ce(C₆H₂S₂O₈)₄¹²⁻ units with 12 Na⁺ counter cations and 10 H₂O molecules (two with half occupancy), and 6 DMF molecules of solvation filling up spaces between cations and anions. Cerium(IV) is in a general position with a coordination polyhedron close to the trigonal-faced dodecahedron, D_2d, with the angles between the two BAAB trapezoids of 2.3^o and 3.7^o. The average CeO(A) distance, 2.363(9) Å is longer than the average CeO(B) distance, 2.326(15)Å, with the reverse being true for one of the four tironato ligands. The average ring OCeO angle is 67.9(1)^o. The cerium (IV) complex is found by cyclic voltammetry to undergo a quasi-reversible one-electron reduction (in strongly basic solution with excess tiron) with Ef=−497 mV vs. SCE, hence the ratio of the formation constants for tetrakis(tironato)cerate(IV) to that for tetrakis(tironato)cerate(III), K_IV/K_III, is 10³³. Characterization of other tiron salts is reported.     

Evolutionary history of the Maltese wall lizard Podarcis filfolensis: insights on the ‘Expansion–Contraction’ model of Pleistocene biogeography

The expansion–contraction (EC) model predicts demographic and range contraction of temperate species during Pleistocene glaciations as a consequence of climate‐related habitat changes, and provides a paradigm for explaining the high intraspecific diversity found in refugia in terms of long‐term demographic stability. However, recent evidence has revealed a weak predictive power of this model for terrestrial species in insular and coastal settings. We investigated the Pleistocene EC dynamics and their evolutionary consequences on temperate species using the Maltese archipelago and its endemic lizard Podarcis filfolensis as a model system. The evolutionary and demographic history of P. filfolensis as inferred from mitochondrial and nuclear sequences data does not conform to the EC model predictions, supporting (i) demographic and spatial stability or expansion, rather than contraction, of the northern and southern lineages during the last glacial period; and (ii) a major role for allopatric differentiation primed by sea‐level dynamics, rather than prolonged demographic stability, in the formation of the observed genetic diversity. When combined with evidence from other Mediterranean refugia, this study shows how the incorporation of Pleistocene sea‐level variations in the EC model accounts for a reverse demographic and range response of insular and coastal temperate biotas relative to continental ones. Furthermore, this cross‐archipelago pattern in which allopatric diversity is formed and shaped by EC cycles resembles that seen between isolated populations within mainland refugia and suggests that the EC model, originally developed to explain population fluctuations into and out‐of refugia, may be appropriate for describing the demographic and evolutionary dynamics driving the high genetic diversity observed in these areas.     

Genetic Differentiation of the Giant Honey Bee (Apis dorsata) in Thailand Analyzed by Mitochondrial Genes and Microsatellites

Genetic diversity and population differentiation of the giant honey bee (Apis dorsata) in Thailand were examined. Six PCR-RFLP mitotypes were generated from digestion of the COI-COII, Cytb-tRNA^ser, ATPase6-8, and lrRNA genes with Dra I and Hin fI. Low genetic diversity (h=0.074, π=0.032%) and a lack of genetic population differentiation between A. dorsata originating from geographically different regions were observed from mtDNA polymorphisms (P > 0.05). In contrast, microsatellite (A14, A24, and A88) polymorphisms revealed a relatively high level of genetic diversity in A. dorsata (H _o=0.68–0.74, average number of alleles per locus=6.0–9.0). Both A24 and A88 indicated significant population differentiation between bees from the north-to-central region (north, northeast, and central regions), peninsular Thailand, and Samui Island.     

The concentration jump method

Lipophilic cationic fluorescent dyes (D) specifically stain the mitochondria of living cells. A perfusion chamber for cell cultures is described, which can be used to determine the kinetics of vital staining of the mitochondria of single selected cells in situ. In these experiments styrylpyridinium dyes and cultures of HeLa cells were used. The dyes differ strongly in their lipophilic properties; R _m values and the partition coefficients P _o/w between n-octanol (o) and water (w) were determined in order to characterize their lipophilicity. In the thermostat-regulated chamber the concentration of the dye C _D can be increased from C _D=0 to C _D>0 within a few seconds (concentration jump). Thus, the time t=0 for the beginning of the vital staining and the dye concentration in the cell medium during the staining experiment, C _D=const., are unambiguously defined. The concentration of the dye, C _b, which is bound to the mitochondria (b), is proportional to the intensity of the fluorescence I _b. On the other hand, the free dye molecules (f) in the aqueous medium exhibit practically no fluorescence, I _fI _b. The intensity of the fluorescence I=I _b was measured as a function of time t; the measured values were corrected for photobleaching. The fluorescence intensity I(t) at first increases linearly with t and reaches a saturation value for t . In the linear range of I(t) the flow J _o=(dI/dt)_o of the dye into the cell depends strongly on the dye concentration and increases linearly with C _D. The concentration range C _D=10^–9–10^–5 M at 37° C was investigated. From the linear correlation between J _o and C _D it follows that the kinetics of the vital staining of mitochondria is controlled by diffusion. At t=0 the flow of the xenobiotic agent through the cell membrane determines the rate of staining. The slope dJ _o/dC _D of the plot J _o vs C _D describes the efficiency of dye accumulation at the mitochondria and strongly increases with increasing lipophilicity of the dye molecules. Thus lipophilic dyes pass through the cell membrane more easily than less lipophilic molecules.     

岛屿生境下黄毛鼠种群的遗传变异

岛屿具有独特的生态系统,常被生态学家和进化生物学家视为研究生物进化的天然实验室,岛屿生物地理学也受到了越来越多科学家的关注。对舟山群岛8个面积不等岛屿的黄毛鼠(Rattus losea)种群进行了调查,分析了8个种群的遗传变异特征,对探讨岛屿理论中的种群动态和种群分化具有重要意义。采用线粒体分子标记技术,利用PCR扩增得到D-loop区基因序列815 bp,在330个黄毛鼠样本中共识别出15个单倍型,平均核苷酸多样性(P_i)为0.001,平均单倍型多样性(H_d)为0.364,表明舟山群岛黄毛鼠种群的遗传多样性较低。Tajima′s D中性检验显示除了小盘峙种群,均为显著负值(P0.01),表明种群受到了自然选择的作用,历史上发生过种群扩张。AMOVE显示,群体间的遗传分化指数平均值为0.745,处于较高的分化水平,表明遗传变异主要来自种群间,占74.5%。基于线粒体D-loop区序列构建的系统发育树和中值网络都表明8个岛屿的黄毛鼠种群起源于两个母系。此外,Mental检验显示不同岛屿种群间的遗传距离与岛屿间地理距离之间存在显著正相关关系(r=0.6077,P=0.004),种群遗传多样性与岛屿面积并未发现显著相关性(r=0.6255,P=0.1840)。研究结果可为岛屿黄毛鼠种群的微观演化以及一些岛屿物种的进化理论提供参考。     

Genetic diversity and differentiation between Palearctic and Nearctic populations of Aedimorphus (=Aedes) vexans (Meigen, 1830) (Diptera,Culicidae)

Genetic diversity was studied at allozyme loci in two Palearctic and one Nearctic population of Aedimorphus (=Aedes) vexans, a species of public health and veterinary importance. The population from Serbia was the most polymorphic (P= 35%) with the highest observed heterozygosity (H_o= 0.027). The lowest observed heterozygosity (H_o= 0.010) was obtained for the Nearctic population. All analyses based on individual (STRUCTURE analysis) and population level (pairwise F_ST,Nm values, AMOVA, Nei's D value) revealed significant structuring between Nearctic and Palearctic populations, indicating a lack of gene flow and thus, the presence of independent gene pools. Taxon‐specific alleles at the diagnostic Ao, Hk‐2, Hk‐3, Hk‐4, Idh‐1, and Idh‐2 loci were used for identification and separation of Nearctic and Palearctic populations. Population genetics study provided valuable information on the correct distinction of Am. vexans populations and their adaptive potential that could find a future use in the studies of vector competence and development of vector‐control strategies.     

Changes in soil phosphorus fractions following positive and negative phosphorus balances for long periods

The effect of phosphorus (P) balance (addition, in both fertilizers and farmyard manure (FYM), minus removal in crops) on eight soil P fractions determined by sequential extraction, was measured on archived soils from various long-term experiments run by Rothamsted Experimental Station in the United Kingdom. It has been established unequivocally that, for all the soils investigated, no one of the eight P fractions was increased or decreased during long periods of P addition or depletion, respectively. However, changes were mainly in the resin (24–30%) and the inorganic (P_i) component of the four fractions extracted sequentially by 0.5 M NaHCO₃, 0.1 M NaOH, 1.0 M NaOH, 0.5 M H₂SO₄ (41–60%). For the sandy loam there were also consistent changes in the organic (P_o) fraction (25%), especially that extracted by bicarbonate, presumably because the soil contained only a little clay and presumably had low sorption capacity. When the soils were cropped without P addition the largest proportional change was in the P extracted by resin, 0.5 M NaHCO₃ and 0.1 M NaOH, suggesting that the P in these fractions is readily available, or has the potential to become available, for crop growth. This was supported by changes in the overall P balance. On the heavier textured soils, 50–80% of the change in total soil P (P_T) was in these fractions; on the sandy soil this increased to more than 90%. The change in the sum of the first five fractions accounted, on average, for 90% of the P balance. However these changes in the P in the plough layer frequently left large amounts of P unaccounted for in some of the excessively P enriched soils. The amount of P_i extracted by resin and bicarbonate (P_i(r+b)) ranged between 14 and 50% of the sum of the P_i fractions. Soils with the lower percentages were those known to be most responsive to P fertilizers. P_i(r+b) accounted for an average of 70% of the P balance (negative) in P depleting soils where crop offtake was not offset or exceeded by annual P additions (positive balance). The ratio between P_i(r+b) and P_i(sum) could be a guide in defining soils deficient in P and those which are excessively enriched.     

Vitamin D content in Alaskan Arctic zooplankton,fishes, and marine mammals

We postulated that dietary ingestion of vitamin D may be used by some Alaskan Arctic marine mammal species in addition to, or instead of, cutaneous production to meet nutritional requirements. Zooplankton (n=5) sampled near Kaktovik, Alaska, contained no measurable vitamin D₂ or D₃, but did contain provitamin D (7‐dehydrocholesterol), the cutaneous precursor for previtamin D₃ in mammals. Fillets and livers from five fish species were sampled near Barrow, Alaska, and evaluated for vitamin D₃ content (no vitamin D₂ was detected). Differences in vitamin D₃ content appeared significant (P≤0.10) among fish livers (Kruskal‐Wallis [H test]=8.25, df=4, P=0.08) and among fish fillets (H=7.80, df=4, P=0.01). We also found significant differences in several pairwise comparisons (Mann‐Whitney U‐test) of vitamin D₃ levels in fillets and livers. Blubber from six species of marine mammals had no detectable vitamin D₂. The H test results for blubber vitamin D₃ concentration were highly significant: 28.12, df=5, P<0.001. There were also significant differences in vitamin D₃ content from blubber in pairwise comparisons of primarily invertebrate feeders (bowhead whale (Balaena mysticetus) [mean=4.20 SD±1.10 ng/g], and Pacific walrus (Odobenus rosmarus divergens) [5.43±2.82 ng/g]) vs. primarily piscivorous feeders (ringed seal (Phoca hispida) [746.57±493.00 ng/g] and beluga whale (Delphinapterus leucas) [426.00±174.92 ng/g]) and a semiaquatic terrestrial carnivore (polar bear (Ursus maritimus) [406.17±311.70 ng/g]). The bearded seal (Erignathus barbatus) had intermediate blubber vitamin D₃ concentration (156.83±139.25 ng/g), which may reflect an intermediate‐type feeding strategy or an artifact of the small sample size. Zoo Biol 23:33–43, 2004. © 2004 Wiley‐Liss, Inc.     

Allometric relationships for estimating the aboveground phytomass and leaf area of mangrove Kandelia candel (L.) Druce trees in the Manko Wetland, Okinawa Island, Japan

Allometric relationships for estimating the phytomass of aboveground organs (stem, branches, leaves and their sum) and the leaf area in the mangrove Kandelia candel (L.) Druce were investigated. The variable D_0.1²H (D_0.1 stem diameter at a height of H/10, H tree height) showed better accuracy of estimation than D² (D, DBH) or D²H. A moderate relationship was found when the branch weight, leaf weight and leaf area were plotted against D_B² (D_B stem diameter at a height of clear bole length). A strong linear relationship was found between leaf area and leaf weight (R²=0.979). The aboveground weight (w_T) showed a strong relationship when plotted against D_0.1²H (R²=0.958), but very weak relationships were obtained against D² (R²=0.300) and D²H (R²=0.316). The w_T also showed a proportional relationship (R²=0.978) to D_0.1²H with a proportional constant of 0.04117 kg cm^–2 m^–1 (R²=0.978). Taking into account the allometric relationships of the weight of aboveground organs or leaf area per tree to different dimensions, such as D², D²H, D_B² and D_0.1²H, a standard procedure for estimating the biomass and leaf area index in the K. candel stand, including the shorter trees, is proposed.     

Coarse-grained population structure in Central European sculpin (Cottus gobio L.): secondary contact or ongoing genetic drift?

Population genetic affinities of 261 European sculpins Cottus gobio L. across the Rhenanian-Danubian and the Rhenanian-Rhónian watersheds were assessed by horizontal agarose-gel electrophoresis of up to 20 allozyme systems (encoded by 29 genetic loci). Polymorphism P_mean= 0.0689 (range: 0.000-0.1379), and heterozygosity H_e(mean)= 0.0167 (range: 0.000-0.0507) indicated low genetic variability within local stocks from single streams. Significant genetic distances D_mean= 0.1917 ± 0.0336 (D_max= 0.2407), based on differential fixation at 3–6 loci (Acp-1**, Pgdh**, Fh**, Est-1**, Gpi-2**, and Pgm-1**) distinguished populations from the Neckar catchment basin from those of the Hochhrein-Oberrhein and Danube basins. Differential fixation of alleles and pronounced genetic distances also separated sculpins of the Rh6nian tributary Doubs from Neckarian populations (D_men= 0.2131 ± 0.0033; Ah**, Acp-1**, Fh**), of the Doubs from the Danube (D_mean= 0.2177 ± 0.0028; Gpi-2**, Pgm-1**, Pgdh**, Ah**), and of the Doubs from the Hochrhein-Oberrhein (D_mean= 0.1780; Pgm-1**, Pgdh**, Ah**). Genetic distances between streams within these drainages proved low (Neckar: D_men= 0.0047 ± 0.0014, Danube: D_mean= 0.026 ± 0.0179, Rhine: D_mean= 0.0308). Screening of another 16 small-size samples consisting of 55 sculpins for nine diagnostic loci (Aat-2**, Acp-1**, Acp-2**, Ah**, Est-1**, Fh**, Gpi-2**, Pgdh** and Pgm-1**) confirmed the genetic homogeneity of sculpins within the Danubian and Neckarian drainage systems, but Neckarian sculpins were similar to those from the river Main. Populations from Hochrhein-Oberrhein resembled the Danubian stock but contained a decreasing frequency of ‘Neckarian’ markers when approaching the Danubian region. The genetic divergence between Neckarian, Danubian and Rhdnian sculpins suggests the existence of hitherto neglected taxa of anteglacial divergence.