The genus Crataegus L.: an ecological and molecular study

This study aimed at the indentification of the species and genotypes of the genus Crataegus in Syria and determination of the genetic relationships among them based on the analysis of genomic and chloroplast DNA (cpDNA) using ISSRs and CAPS techniques. Morphological characterization carried out on 49 Crataegus samples collected from different geographical regions of Syria revealed four Crataegus species: C. monogyna, C. sinaica, C. aronia and C. azarolus. In the dendrogram constructed for those samples based on ISSRs (20 primers), all samples that belong to C. monogyna were clustered in one cluster. Samples of the other three species were overlaped in another cluster. Two samples of these were the most distant from all other samples in the dendrogram and were suggested to represent hybrid species or subspecies. When CAPS technique was applied on four Crataegus samples that represent the four suggested species using 22 cpDNA regions and 90 endonucleases, no polymorphism was detected neither in amplification products sizes nor in restriction profiles. The inability of detection of variation in cpDNA among species suggested can be attributed to the low level of evolution of the cpDNA in the genus, and to the possibility that some of these species are either subspecies or hybrids since the cpDNA is inherited through one parent only.     

Influence of sediment fertility on morphological variability of Vallisneria spiralis L.

One homogeneous and three heterogeneous nutrient enrichment treatments were imposed to investigate the growth responses of Vallisneria spiralis L. Morphological features of V. spiralis differed significantly between different nutrient patches. Roots elongated in nutrient-poor patches, and the specific root length (SRL) also increased significantly. Stolon length, diameter and leaf length and width increased significantly in nutrient-rich patches. Total plant biomass of V. spiralis grown in the homogeneous and three heterogeneous treatments on average were 2.9, 3.0, 3.9 and 2.3 fold higher than that grown in the control treatment. Number of ramets per clone was significantly higher in the heterogeneous treatments than in the homogeneous treatment. In three varying heterogeneous treatments, ramet biomass in nutrient-rich patches was 2.7, 4.3 and 3.0 fold higher than in nutrient-poor patches; however, ramet number was not affected by sediment nutrients, resulting in bigger ramets in nutrient-rich patches. The biomass allocation established adaptive plasticity to heterogeneous environments. The maximum value of biomass allocation to underground parts reached 16% in nutrient-rich patches, whereas the minimum value of underground parts reached 20% in nutrient-poor patches. Results demonstrate that clonal V. spiralis can maintain itself preferentially in favourable nutrient-rich sediments, whereas nutrient-poor conditions could be escaped by plastic biomass allocation.     

Competitive interactions between Fucus spiralis L. and F. vesiculosus L. (Fucales,Phaeophyta)

Fucus spiralis forms a conspicuous belt in the upper intertidal on rocky shores of the NW Atlantic. The objective of this study was to determine whether competition among congeners plays a role in restricting the distribution of F. spiralis to the upper shore. A replacement series design was used to test the growth performance of F. spiralis and F. vesiculosus in monocultures and in mixtures set up in the mid shore level on an exposed rocky coast. For F. spiralis and F. vesiculosus, all individual and relative crowding coefficients were < 1 and > 1, respectively. Hence, F. vesiculosus succeeded relative to F. spiralis in all mixtures tested. This finding was confirmed by graphical analysis. Ratio diagrams showed that the outcome of long term interaction among the species is extinction of F. spiralis. The results lead to the conclusion that interaction among congeners is a major determinant of the restricted distribution of F. spiralis.     

The ecological study of memory.

The study of memory has long been dominated by the structural tradition, and especially by the experimental analysis of mechanisms of information processing. That dominance may soon be brought to an end by the progress of neuroscience, which offers more direct ways of studying the mechanisms in question. At that point functional issues may move to centre stage. Those issues include the act of remembering and its social functions, the skills and presuppositions of the remembered, the interaction of those skills and presuppositions with the particular material being remembered, and the determinants of accuracy and confabulation in recall.     

An ecological study of chimpanzees in a savanna woodland

From May, 1964, to September, 1965, the author made ecological and sociological studies of wild chimpanzees (Pan troglodytes) in Western Tanzania, East Africa. The vegetation of this area belongs to theBrachystegia andIsoberlinia savanna woodland. During the dry season, chimpanzees go out into the open forest and chiefly eat the hard seeds ofJulbernardia, Brachystegia, Isoberlinia, Pterocarpus, etc.The continuity of the group of chimpanzees is not stable but temporary, as has been reported byGoodall, etc. The author termed such a temporary group nomadic group. A big nomadic group, such as that consisting of 43 individuals at Filabanga, seems to be one unit of a chimpanzee's society.The nomadic range of the chimpanzees in the savanna woodland covers about 100 km² (201 km² in the Kasakati area). This is greater than that of the chimpanzees living in the forest, and such a large range has not been previously known among other non-human primates.This study was made possible by the Overseas Scientific Research Fund of the Ministry of Education.     

An ecological study of Hanuman langurs,Presbytis entellus

A troop of 23 Hanuman langurs was studied for a year in the dry deciduous forest at Dharwar, South India. The size of the territory and the home range of the troop was reduced due to a new-group formation during the period of this study, but the area size per each member of the troop did not change much. No distinct seasonal use of different parts of the range was observed. There was a tendency toward increased activities, especially feeding, toward the evening. However, feeding was frequently observed during the daytime. The langurs ate leaves, stalks, shoots, buds, flowers, and the fruit of many plant species, and they well utilized the common and abundant species in the area as food. The langurs spent 20% to 40% of the daytime on the ground. And they moved longer distances on the ground than they did in trees. When feeding on the ground, they changed food plants more frequently, moving more often and longer distances, than when feeding in trees. The home range of the langur troop overlapped with that of a troop of bonnet monkeys, but the relations between the two species were rather peaceful.The field work on which this report is based was financed by a Rockefeller Foundation grant, RF 60229, for the study on the behavior of Indian monkeys.     

An ecological study of three fresh water ponds of Hyderabad-India

Summary The fluctuation of pH, calcium and bicarbonate contents of water were influenced by dissolved carbon dioxide. Invariably the concentration of calcium and bicarbonate were complementary to each other, but on certain occasions sodium and iron also behaved like calcium towards bicarbonate.The accumulation of soluble organic matter in water depended largely on the density of phytoplankton population and also on magnesium and the Ca/Mg ratio.The concentration of nitrate increased in these waters either after the early rains or towards the end of monsoon season. Possibly it depended on the nature of the catchment area and on the intensity of bacterial activity.The salinity and total solid contents of water varied together. Waters sustained more total solids when the pH was around 7.8. The % soidum and % Cl + NO₃ fluctuated directly with salinity and apparently indicated pollution of animal origin. Sodium and chlorides showed a direct relationship.Part of the thesis approved for the Ph.D. Degree of the Osmania University, 1969.     

Phototrophic biodeteriogens on lithoid surfaces: An ecological study

For two strains, the green alga Pleurococcus CVB4 and the cyanobacterium Lyngbya CCB2, isolated from the pioneering algal biocoenosis present on a marble statue, we determined the optimum range of growth in selective cultural media in relation to pH, light intensity, and temperature, together with the ability of these organisms to colonize stone surfaces that differed either in the structure-texture or in the physico-chemical composition of the various lithotypes. The results showed a higher capacity of the green alga to withstand environmental factor changes. For both organisms the preferential colonization of the stone surface was correlated primarily, together with the environmental factors (pH, temperature, irradiance), to the physical characteristics (roughness and porosity) and secondarily to the chemical composition of the assayed lithotypes.     

The genus <Emphasis Type="Italic">Crataegus</Emphasis> L.: An ecological and molecular study

This study aimed at the indentification of the species and genotypes of the genus Crataegus in Syria and determination of the genetic relationships among them based on the analysis of genomic and chloroplast DNA (cpDNA) using ISSRs and CAPS techniques. Morphological characterization carried out on 49 Crataegus samples collected from different geographical regions of Syria revealed four Crataegus species: momogyna, C. sinaica, C. aronia and C. azarolus. In the dendrogram constructed for those samples based on ISSRs (20 primers), all samples that belong to C. monogyna were clustered in one cluster. Samples of the other three species were overlaped in another cluster. Two samples of these were the most distant from all other samples in the dendrogram and were suggested to represent hybrid species or subspecies. When CAPS technique was applied on four Crataegus samples that represent the four suggested species using 22 cpDNA regions and 90 endonucleases, no polymorphism was detected neither in amplification products sizes nor in restriction profiles. The inability of detection of variation in cpDNA among species suggested can be attributed to the low level of evolution of the cpDNA in the genus, and to the possibility that some of these species are either subspecies or hybrids since the cpDNA is inherited through one parent only.     

Biometrical and ecological observations on Cistus salvifolius L.

Abstract

Biometrical observations on Cistus salvifolius L. (Cistaceae), a species with a very variable morphology, are presented: data, collected in Sicily, are relative to three environments in which populations of Cistus salvifolius live: garigue, maquis, pinewood. Measurements are compared with other ones, found in the literature, and in some cases they disagree or supply useful indications. On the basis of the different light regimes in the three environments, and of the parameters in which the difference among the three populations is most evident, some observations about the reaction to shade in Cistus salvifolius were made. On the basis of the few data collected, the intraspecific differences were given a possible explanation with the light factor: these differences are relative to morphological parameters such as leaf area, petiole length, stem length, and also to “derived” parameters such as specific leaf area and petiole length/leaf length ratio.     

An ecological basis for the conservation management of Polygonatum verticillatum (L.) All. (Convallariaceae)

Summary

Populations of Polygonatum verticillatum were studied in Scotland and south-west Scandinavia. Soil fertility and light appear to be the most important factors determining vegetative vigour and reproductive potential affecting rhizome size and flower production. Differences between the two geographic areas and between different habitats are discussed in the context of the rarity of P. verticillatum in Scotland and the need for informed conservation.     

An ecological study of the viper Vipera berus in southern Britain

A general ecological study was made of the Northern viper (adder) in Dorset. The principal aim was to obtain a detailed account of its seasonal activity and then to relate this to its habitat and other requirements. 166 marked individuals were studied in the field for at least three seasons and additional information was obtained from 194 post-mortem examinations and from studies of live individuals in an enclosure. It was found the viper occupies two distinct habitats, high, dry ground for winter hibernation and low-lying damp river meadows in the summer. Feeding essentially occurs from June to August and breeding is restricted by the short active season to alternate years. This study forms part of the research being carried out to help with the conservation of the British reptiles on the National Nature Reserves in this part of England.     

Trichinella spiralis in an agricultural ecosystem. II. Evidence for natural transmission of Trichinella spiralis spiralis from domestic swine to wildlife

Epidemiological investigations of an outbreak of trichinellosis were carried out in a domestic swine herd and it was established that the parasite also occurred in rats, and in skunks, opossums, and raccoons. Because considerable uncertainty exists regarding the role of sylvatic trichinellosis as a reservoir for the synanthropic cycle, studies were conducted to determine the genetic nature of the various isolates from this ecosystem. Pig infectivity trials, isoenzyme analyses, and repetitive DNA sequence analyses were performed. The results showed that all isolates from the farm environs were genetically similar and that they are related to Trichinella spiralis isolated from domestic pigs. The implication of these findings, in contrast to studies on isolates from wildlife elsewhere, is that this parasite is transmitted from domestic swine to sylvatic hosts and that any control or eradication efforts must take into account the potential for reinfection of hogs from wild animals.