Structure of plant communities and cenopopulations of Astragalus serioceocanus Gontsch. on the shore of Lake Baikal

Plant communities with Astragalus sericeocanus have been studied. Data on the ontogenetic structure and quantity of cenopopulations, as well as the seed productivity of their individuals, are given. It has been revealed that the habitats on the northern shore of Lake Baikal are characterized by high phytocoenotic diversity with the dominance and codominance of A. sericeocanus. The state of cenopopulations and parameters of seed productivity indicate that the northern habitats of Lake Baikal have more favorable conditions due to the optimal climatic characteristics for the growth and development of the species.     

Ecological and biological features and prospects of protection of Menispermum dauricum DC. (Menispermaceae) in Western Transbaikalia

The condition of cenopopulations of the relict of nemoral (Pliocene) flora Menispermum dauricum DC. is considered. Three new habitats of the species are found in Western Transbaikalia. It is shown that, although the species is an ecotopic patient, local cenopopulations on mountain-steppe slopes are influenced by destructive exogenous geomorphological processes.     

Ontogenetic structure and vitality of the cenopopulations of <Emphasis Type="Italic">Oxytropis sulphurea</Emphasis> (Fisch. ex DC.) Ledeb. in different ecocenotic conditions of Rudny Altai and the Saur Ridge

This article presents the results of an analysis of ontogenetic and vitality structure of seven cenopopulations of Oxytropis sulphurea (Fisch. ex DC.) Ledeb. in the high-altitude conditions of Rydny Altai (Ivanovsky and Prohodnoi ridges) and the Saur Ridge. In the study of the demographic structure it has been determined that most populations from undisturbed habitats are characterized by left-side spectrums with maximums on juvenile or immature individuals. The changes in the structure of the studied ontogenetic spectrums of this species depend largely on the presence of anthropogenic influence. Grazing pressure has led to the formation of spectrums with a maximum on g₃ plants. The vitality type of the O. sulphurea populations varies from exuberant to depressed; the depressed and balanced types of vitality prevailed. Intensive seed propagation provides a stable existence of O. sulphurea in the high-mountain alpine zone. The results of our study show that O. sulphurea is an alpine-meadow species which has strict ecological and cenotic propensity for alpine meadows with the prevalence of Festuca kryloviana, Anthoxanthum alpinum, and Schulzia crinite and shrub tundras with Dryas oxyodonta.     

On the ecology of the species of the genus <Emphasis Type="Italic">Hylotelephium</Emphasis> H. Ohba promising for city phytodesign in the south Urals

The two-factor variance analysis revealed the statistically significant influence of the conditions of habitat and weather in the year of study on the majority of morphometric parameters of vegetative and generative sphere of four natural cenopopulations of Hylotelephium stepposum (Boriss.) Tzvel. and three cenopopulations of H. triphyllum (Haw.) Holub.     

Generalized spatial mark–resight models with incomplete identification: An application to red fox density estimates

相似文献   

Increased temperature disrupts chemical communication in some species but not others: The importance of local adaptation and distribution

Environmental conditions experienced by a species during its evolutionary history may shape the signals it uses for communication. Consequently, rapid environmental changes may lead to less effective signals, which interfere with communication between individuals, altering life history traits such as predator detection and mate searching. Increased temperature can reduce the efficacy of scent marks released by male lizards, but the extent to which this negative effect is related to specific biological traits and evolutionary histories across species and populations have not been explored. We experimentally tested how increased temperature affects the efficacy of chemical signals of high‐ and low‐altitude populations of three lizard species that differ in their ecological requirements and altitudinal distributions. We tested the behavioral chemosensory responses of males from each species and population to male scent marks that had been incubated at one of two temperatures (cold 16°C or hot 20°C). In high‐altitude populations of a mountain species (Iberolacerta monticola), the efficacy of chemical signals (i.e., latency time and number of tongue flicks) was lower after scent marks had been exposed to a hot temperature. The temperature that scent marks were incubated at did not affect the efficacy of chemical signals in a ubiquitous species (Podarcis muralis) or another mountain species (I. bonalli). Our results suggest that specific ecological traits arising through local adaptation to restricted distributions may be important in determining species vulnerability to climatic change.     

Traumatization of Kamchatka River Pacific salmon by lampreys

Salmon that enter the Kamchatka River are intensively traumatized by lamprey (from 12.0 to 74.0% in different years). An analysis of the frequency distribution of oral disk marks on salmon revealed two types of marks: (1) small (diameter < 2.2 cm, mainly of oval form, located in the middle of the fish in the upper part of the body) and (2) large (diameter > 2.2 cm, of roundish form, located in the front in the lower third of body). The small marks (type I) are mainly left by the Kamchatka lamprey Lethenteron camtschaticum. The second type of trauma is inflicted by large individuals of the Pacific lamprey Enthosphenus tridentatus in the 2nd and 3rd year of marine life. The most typical traumatic injuries caused by lamprey to salmon are described. Injury data are provided for six species of salmon, namely, sockeye, pink, chum, coho, chinook, and char.     

Population structure of Potentilla bifurca L. in the Altai-Sayan Mountain Region

Pollen characters were analyzed in 16 cenopopulations of Potentilla bifurca L. in five provinces of the Altai-Sayan Mountain Region. As a result, two groups of cenopopulations, western and eastern, have been recognized. Both groups are characterized by a high intrapopulation (44.7–63.9%) and a lower interpopulation (11.4–42.2%) variability. The observed similarity between groups of cenopopulations of P. bifurca from different geobotanical provinces is determined by their common origin from the Pliocene-Pleistocene steppe communities.     

Roles of Different Types of Excretions in Mediated Communication by Scent Marks of the Common Palm Civet, Paradoxurus hermaphroditus Pallas, 1777 (Mammalia, Carnivora)

We studied scent-marking behavior, olfactory response to various excretions (secretion of the perineal gland, urine, and feces), as well as the information content of these excretions in the common palm civet (Paradoxurus hermaphroditus Pallas, 1777). Six forms of scent-marking behavior have been described. The activity and proportion of forms of such behavior differ in males and females. Dragging the perineal gland and leaving the secretion on the substrate was most commonly observed in the animals of both sexes. The olfactory response of the palm civet varied in duration and depended both on animal sex and excretion type. The palm civet could distinguish animal species, sex, and familiar/unfamiliar individuals by the odor of the perineal gland secretion. Differences in the olfactory response of the palm civet to feces was observed only if they belonged to different species. The scent marks of the perineal gland were most significant in mediated communication by scent marks of the palm civet; they completely replicated the information of the urine marks.     

Home Range,Population Density,and Food Resources of Agouti paca (Rodentia: Agoutidae) in Costa Rica: A Study Using Alternative Methods1

Field studies of elusive mammals such as Agouti paca are difficult, and results are often biased and incomplete because the animals are nocturnal and avoid traps. By studying an A. paca population in a Pacific lowland forest of Costa Rica, we developed indirect observational methods to estimate population density and food resource utilization. To estimate population density, we divided the number of A. paca burrows found in a 12-ha census area by the average number of burrows utilized per individual from radiotelemetry data. We compared this estimate to independent population estimates obtained using two transect methods. Agouti paca density was estimated at 93 individuals/km² based on burrow number, and between 67 to 70 individuals/km² using transect methods. This discrepancy corroborates previous studies suggesting that transect methods underestimate population density. To identify food resources consumed by the species, we collected fruits and seeds with unambiguous A. paca teeth marks. The only animal in Central America with an incisor width similar to A. paca. is Dasyprocta variegata; in a comparison of both species, however, we found that A. paca had a significantly larger incisor width and that teeth marks of 4 mm or wider unambiguously indicated handling by this species. By applying this technique, food resources utilized by A. paca can be identified more easily than by direct observation. At our study site, we identified 33 plant species consumed by A. paca; 61 percent are new records for this animal. Our results suggest that A. paca plays a major, although not fully understood, ecological role in seed predation and dispersal.     

Assessment of Hedysarum theinum Krasnob. (Fabaceae) population status in Altai

The status of 22 Hedysarum theinum cenopopulations (CPs) located in subalpine and alpine vegetation belts in Kazakhstan and Altai Republic is assessed by a complex of traits. It is detected that conditions of the subalpine belt (12 CPs), where the point sum of organismal and population traits vary from high to average values, are the most favorable for this species. The pessimal state, characterized by the smallest values of most species parameters, is determined in the alpine vegetation belt at an altitude of about 2000 m above sea level in Rudnyi Altai (Kazakhstan) and a shrub community at the junction of alpine and subalpine belts on the edge of the H. theinum area in Russian Altai. A reactive-tolerant type of H. theinum population strategy is detected.     

Anatomical wood variation of Buddleja cordata (Buddlejaceae) along its natural range in Mexico

Buddleja cordata is an evergreen species of wide distribution in Mexico that is represented by shrubs and trees. Wood variability of B. cordata was evaluated in relation to plant size as well as latitude, altitude, soils, and climatic data. Canonical correlation analysis (CCA) showed that two canonical correlations are significant (Wilks' λ, p<0.0001) and explained 76% of total variance. Redundancy analysis revealed that the first pair of canonical variates are significant, thus the canonical variate, named distribution, represents a gradient of maximum temperature of the warmest period, annual temperature range, and latitude in its area of distribution; whereas the canonical variate named wood represents vessel density, fiber length, and plant size, best associated to the environmental gradient. Vessel density expressed by its distribution in latewood and porosity type showed that ring-porosity is common in individuals from high latitudes. Temperatures below zero or lack of rainfall during several months might induce porosity variability in B. cordata as suggested by CCA, but was not related to phenology since the species is evergreen along its latitudinal range. Plant size was also influenced by extreme temperature and rainfall. Shorter plants are distributed in the northern population or driest sites located in north-central Mexico, and in addition, fiber length followed an allometric relation with individuals' height. Wood characters in B. cordata as for simple perforation plate, helical thickenings, type of intervascular and vessel-ray pits, scanty paratracheal parenchyma, and heterogeneous type IIB rays were not correlated with plant size, climate, and soil parameters or species distribution. These features are common with other species of Buddleja.An erratum to this article can be found at     

Permanent plot research in wet meadows and cutting experiment

Vegetation mowing is usually recommended for preserving wet meadows, in particular for the prevention of land warping and brushwood encroachment. The concept and the methods for the study of the influence of different cutting rhythms on the vegetation of two wet meadows, as well as some short term results are presented. Cutting experiments with permanent plots have been undertaken in vegetation communities such as Orchio-Schoenetum nigricantis and Caricetum elatae, abandoned for many years. The strategy of the study was to have diverse but complementary methodological approaches in order to assess changes in the vegetation and species abundance, especially concerning the botanical composition, the vegetation structure and the species vitality. The methods include counting of plants or part of plants, morphometry of Phragmites communis, biomass measurements, phenological records, structure relevés with the point-intercept technique as well as classical vegetation relevés with coverage estimation.On a short term base we can conclude, on the whole, that the yearly winter cut treatment induces a better vitality (number of individuals, flowering, biomass) of the studied species, while in the control plots the vitality is low, due notably to the important layer of accumulating litter and the lack of light on the ground, which hamper soil warming. The yearly summer cut treatment and the winter cut made every three years show in general intermediate characteristics. Furthermore, the vegetation structure is noticeably different according to whether the vegetation is cut (with hay removal) or not. Concerning the methodology, it is concluded that a diverse approach is a good way to assess changes in the vegetation with a minimum loss of information. If the rather subjective method of vegetation relevés with cover estimation may be suitable for long term survey on permanent plots, more quantitative and objective techniques have to be set if short term or precise changes in the botanical composition, the species vitality and the biomass, as well as structural changes, are sought.This paper was presented at the meeting of the working Group for Succession on Permanent Plots, held in Bern (Switzerland), 4th–7th September 1991.     

Die Plastidenzahl als Merkmal bei der Kartoffel

Summary The average number of plastids in ten pairs of guard cells is a very useful aid for screening haploids among tetraploid plants fromS. tuberosum x S. phureja.In individual seedlings the stomatal plastid number decreases from the cotyledons to the first leaves. From the lower to the upper part of stems there exists a decreasing gradient for plastid number and an increasing gradient for the number of stomata per leaf area unit, whereas the stomatal length does not show a consistent trend.In the stomata, plastid number and stomatal length are positively correlated.Mean numbers of plastids in guard cells increase by a factor below 2 (1.8–1.9) after each doubling of the chromosome number.The stomatal plastid numbers of 48-chromosome breeding lines and of their haploid progenies show a clear positive correlation. The mean plastid numbers in various haploid families from different mother plants display significant differences.The origin of the cytoplasm (plasmone + plastome) fromS. demissum, S. stoloniferum, S. tuberosum, andigena forms ofS. tuberosum orS. spegazzinii in which the genome of the haploid is incorporated definitely influences the number of plastids in the guard cells.The stomatal numbers of plastids in 72 trisomic haploids show no significant deviation from the normal distribution of plastid numbers in haploids.Plastid number and stomatal length show a positive correlation in a population of 48 haploid lines and also in the same lines after doubling and quadrupling the chromosome number, the coefficient of regression decreasing with increasing ploidy level. In the above mentioned material there exists a strong positive correlation between the haploid and the corresponding homodiploid plants concerning stomatal length and the number of plastids.A comparison of the correlation stomatal length/plastid number at the 24-, 48- and 96-chromosome levels in three different genotypes reveals that some individuals are more sensitive to a rise in ploidy level than others and that the stomatal plastid number is a more reliable indicator of ploidy level than the stomatal length.We found some scattered polysomatic doubled stomata in leaf epidermissystems, stolons and tuber primordia of potatoes from various ploidy levels. The stomata at the border of the lamina are regularly endomitotically doubled, regardless of the original ploidy level.The hypothesis of a specific basic number of plastids for a given species, multiples of which should give origin to tissue-specific numbers, is criticized.High plastid numbers were negatively correlated with vitality. potatoes the possible correlation between plastid number in haploids and the direction of their original phyllotacticAs both the plastid number and the direction of the phyllotactic leaf spiral show some correlation with vitality in potatoes the possible correlation between plastid number in haploids and the direction of their original phyllotactic spiral was tried. The two groups with low and normal stomatal plastid numbers displayed almost equal distribution between left- and right-directed spirals; in the category with high plastid number, however, this relation was significantly displaced in favor of right spirals. It is tentatively proposed that both vitality and the direction of the phyllotactic spiral are governed by a common hormonal principle (pissibly auxins) which also influences the number of plastids.     

A nested parasite species subset pattern in tropical fish: host as major determinant of parasite infracommunity structure

The number of monogenean gill parasite species associated with fish hosts of different sizes is evaluated for 35 host individuals of the West African cyprinid Labeo coubie. The length of host individuals explains 86% of the total variation in monogenean species richness among individuals. Larger hosts harbour more species than smaller ones. The existence of a hierarchical association of parasite species in individuals of L. coubie is demonstrated. Monogenean infracommunities on larger fish hosts consist of all species found on smaller hosts plus those restricted to the larger size categories, suggesting some degree of compositional persistence among host individuals. The findings provide strong support for an interpretation of the relationship between monogenean parasite species richness and host body size in terms of a nested species subset pattern, thus providing a new record of repetitive structure and predictability for parasite infracommunities of hosts.After 15/01/1995, ORSTOM, BP 165 97323 Cayenne cedex Guyane France     

A simple laser photogrammetry technique for measuring Hector's dolphins (Cephalorhynchus hectori) in the field

The ability to measure and age individuals within a population has many important applications, for example, for examining growth and determining size class. We developed a simple photogrammetric system using two parallel lasers and a digital camera, in order to measure dorsal fin dimensions of free-ranging Hector's dolphins. Laser dots were projected onto the fin, providing scale, thus allowing measurement as well as simultaneous photo-ID of 34 individuals from fin nicks and other marks. Multiple measurements (≥5) were available for six individuals; these resulted in mean CVs of 3.71% for fin length and 3.76% for fin height. Errors due to variations in angle and measurement were quantified via photography of a fiberglass Hector's dolphin model. Allometric measurements and age data were collated from 233 autopsied Hector's dolphins. Using these data, fin length was found to be a better predictor of total length (females r²= 0.732, males r²= 0.678) than fin height. Gompertz age/length growth curves were fitted to these individuals. Linear regressions were used to estimate total length for 34 individuals from laser-metrically estimated fin base length. Individuals were then assigned one of three age categories. This system shows promise as a noninvasive way of measuring individuals, while allowing simultaneous photographic identification.     

Demography of the seedling bank of Manilkara zapota (L.) Royen,in a subtropical rain forest of Mexico

Selection of individuals in tropical trees, occurs mainly in the seedling phase, which in part explains the low densities of most species. The main objective of this work was to gain an insight into those factors that influence growth and survival of Manilkara zapota seedlings, one of the most abundant species in the lowland forests of Mexico and Central America. Eight 10-m² rectangular plots (5m×2m) were established, in which all < 35-cm-high M. zapota seedlings were marked, measured and enumerated at bimonthly intervals. In each census seedling height, number of leaves, length of largest leaf, type of damage and seedling death were registered. Seedling survival during 2 yr was high, reaching 82% including newly emerged seedlings. A maximum likelihood regression analysis showed that both number of leaves and length of largest leaf had a direct influence on seedling survival; however, neither type of damage nor seedling density and height had significant effect. Seedling height growth averaged 2.8 cm in the 2 yr of study. The combined effect of high seedling survival, reduced growth, and impact of physical damage mainly due to falling branches and leaves reveals the occurrence of a persistent seedling bank. Such a bank would contribute to recruitment of individuals in the juvenile and eventually in the adult stages. This seedling bank could explain the high density of individuals of M. zapota in the tropical forests of Mexico.     

Ribosomal DNA variation within and among individuals ofLisianthius (Gentianaceae) populations

Restriction endonuclease fragment analysis of nuclear ribosomal DNA (rDNA) was completed on 25 individuals each from seven populations of theLisianthius skinneri (Gentianaceae) species complex in Panama. Seven restriction enzymes were used to determine the amount and type of rDNA variation within and among individuals of the populations. No restriction site variation was seen within populations or individuals although site differences were seen among populations. Spacer length variation within and among individuals of populations was mapped to the internal transcribed spacer (ITS) region between the 18S and 5.8S rRNA genes, a region inLisianthius rDNA that previously was shown to exhibit length differences among populations. This is the first reported case of such variation within and among individuals of populations for the ITS region. Presence or absence of ITS spacer length variation is not correlated with levels of isozymic heterozygosity within populations. No detectable length variation within individuals or populations was seen in the larger intergenic spacer (IGS). Although populations varied with respect to IGS length, all individuals of a given population had a single and equivalent IGS length.     

Two new species of Acanthobothrium Beneden, 1849 (Tetraphyllidea: Onchobothriidae) from horn sharks in the Gulf of California,Mexico

Between 1993 and 1996, 26 individuals of two species of horn sharks were collected from the upper Gulf of California and their spiral intestines examined for onchobothriid tapeworms. Heterodontus francisci was found to host Acanthobothrium puertecitense n. sp. Based on the criteria of Ghoshroy & Caira (2001), this is a Category 4 species (with >15mm total length, >50 proglottids, >80 testes and a symmetrical ovary). It differs from the four Category 4 species previously reported from either the western Atlantic or eastern Pacific Oceans, including A. bajaense (emend.) which was described from H. francisci, in hook-shape, total length, number of proglottids, number of testes and number of columns of vitelline follicles. H. mexicanus was found to host Acanthobothrium santarosaliense n. sp., which, based on the criteria of Ghoshroy & Caira (2001) is a Category 3 species (with >15mm total length, >50 proglottids, >80 testes and an asymmetrical ovary). A. santarosaliense differs from the five Category 3 species previously reported from either the western Atlantic or eastern Pacific Oceans in its size, euapolytic nature, lack of dark matrix from the bases of the hooks, hook-shape, and distribution and number of testes. In addition to the difference in ovarian symmetry, A. puertecitense possesses fewer testes, fewer proglottids, is a shorter worm, possesses a more anterior genital pore and vitelline follicles which extend further forward anteriorly than in A. santarosaliense. This represents the first report of onchobothriids from H. mexicanus and the first report of onchobothriids from H. francisci in the Gulf of California. The apparent host-specificity of both new species should be viewed with caution until a greater sample of host individuals of both species can be examined. The fact that both new tapeworm species are known only from the Gulf is also considered to be a preliminary result, given the small sample of host individuals examined from these regions to date. This brings the total number of species of Heterodontus known to host Acanthobothrium to four and the total number of Acanthobothrium species described from heterodontiform sharks to five.     

Do different competitive abilities of three fern species explain their different regional abundances?

Question: Do different competitive abilities of three fern species explain their different regional abundances? Location: Estonia, Europe. Methods: The factorial pot experiment, in which single individuals of three fern species were grown in natural soil with 0, 2,4, and 8 neighbouring individuals of Deschampsia flexuosa. Results: The response patterns of different biomass fractions and morphological parameters of fern species were similar to each other. The diploid D. expansa was the most vulnerable to competition, while tetraploid D. carthusiana and D. dilatata were more tolerant. D. carthusiana allocated relatively more to below‐ground parts than the other two species and allocation to roots increased when neighbour density increased. For D. expansa and D. dilatata, allocation to below‐ground parts decreased at high neighbour density, while in D. dilatata also the relative length of the stipe increased. Thus, the response of D. carthusiana corresponds to a ‘persistence type’ and that of D. dilatata to a ‘foraging type’. Conclusions: Lower vulnerability of D. carthusiana to competition, compared to D. expansa, may explain the higher regional and local abundance of the former. The rarity of D. dilatata in Estonia, however, could rather be explained by the impact of climatic factors, since this species is near its northeastern distribution limit in Estonia.