Comparative studies of vegetative anatomy in the Theaeeae of Sri Lanka

Anatomical characters of the mature leaf blade, petiole, young stem and wood were examined in order to substantiate taxonomic boundaries between genera and species of Theaeeae in Sri Lanka. Two species of Temstroemia , one of Adinandra , four of Eurya and two of Gordonia were studied.
The presence of sclereids in most organs of the plant was found to be a common character within the family. However, three distinct types of sclereid are reported. Two basic types of stomata, anomocytic and gordoniaceous, are recognized. The origin of phellogen in the young stems is pericyclic in Gordonia and subepidermal in the other three genera. The species within these genera also appear to have several distinctive characters of their own. Important wood characters have been tabulated in order to illustrate the primitive and advanced characters. Gordonia , especially, exhibits anatomical features which are quite different from those of Temstroemia, Adinandra send Eurya.     

The Cladocera of Sri Lanka (Ceylon), with remarks on some species

The freshwater Cladocera of Sri Lanka has been revised based on the study of over 700 zooplankton samples collected from all habitat types during 1965–1980. The cladoceran fauna is represented by six families; members of the families Polyphemidae, Leptodoridae and Holopedidae are absent. The common temperate genus Daphnia is rare.Sixty-two species have been recorded from Sri Lanka. Of these, five are new records. Remarks on a few species are given with illustrations. The distribution of Cladocera in different types of habitats is discussed. The greatest species diversity was found in ponds. The Sri Lankan fauna is numerically and in species diversity typical of tropical cladoceran fauna. It resembles the southern Indian fauna very closely except for the absence in Sri Lanka of the genera Acroperus and Camptocercus.     

Threats to the indigenous freshwater fishes of Sri Lanka and remarks on their conservation

Sixty-two freshwater dispersant (26 endemic), 26 saltwater dispersant and 20 exotic fishes have been recorded from Sri Lanka's inland waters. The discovery of nine new species of freshwater fish during the past decade suggests that Sri Lanka's fish fauna is not yet well known and that further discoveries can be expected. All the new species, and almost all the endemic ones, have been recorded from forested areas in the foothills of the southwestern wet zone and the Knuckles hills. The known ranges of many species are exceedingly small; almost all of them are habitat specialists. 25 species have at least two strong habitat preferences (in almost all case, shade being one), though a majority (32 species) have none. Habitat alteration is therefore the greatest threat to their survival.Eight freshwater fish species are considered endangered and a further five, vulnerable. Three species are rare, 18 common and 13 abundant. All but two of the endangered species and all the vulnerable species are endemic in Sri Lanka. Nine species are each restricted to only one drainage basin, and seven have a known range < 50 km². Three species of diadromous gobies known only from small populations are considered vulnerable.Examination of the existing threats suggest that deforestation, the widespread dispersion of exotics, pollution caused by agricultural chemicals and increasing pressure from the food fishery present the greatest threats to fish populations. While the endemic fishes are restricted to or most abundant in the wet zone, the overwhelming extent (> 95%) of Sri Lanka's nature reserve areas are in the dry zone. A programme to maintain self-sustaining captive populations of the endangered species is urgently necessary.     

The seasonality of monsoonal primary productivity in Sri Lanka

The relationship between phytoplankton primary production and seasonality of physico-chemical parameters were examined for five man-made lakes in the dry-zone of Sri Lanka. Sri Lanka experiences two monsoons dividing the year into four meteorological seasons: — the North East (October–December) and South West (April–June) monsoons and the two inter-monsoons. A significant log linear relationship was found between Secchi disc depth and the depth of the euphotic zone which was lowest during the NE monsoon. Maximum mean photosynthetic rate ranged from 0.935 ± 0.067 SE to 0.479 mg O₂l^–1 h^–1 ± 0.115. Gross primary productivity which ranged from 0.378 g O₂ m^–2 h^–1 in the NE monsoon to 0.980 g O₂ m^–2 h^–1 in the SW monsoon showed significant season variation. This is shown to be determined either directly or indirectly by the light regime.     

The Freshwater Zooplankton of Sri Lanka,with a Discussion of Tropical Freshwater Zooplankton Composition

Based on the study of over 500 zooplankton samples collected in Sri Lanka (Ceylon) during 1965–1974, the species composition from different habitats is analysed. The zooplankton assemblage is typically tropical with relatively few species of Cladocera and Copepoda. The Rotifera include a large number of species of the genus Brachionus. The limnetic zooplankton resembles the pond zooplankton closely in that all the eurytopic species found in the different types of habitats, including ponds, also occur in the limnetic zooplankton. The large Cladocera belonging to the genus Daphnia are very rare. In general, large zooplankters are absent. The size composition of the zooplankton has a smaller range than in temperate regions. This is due to the absence of large-sized zooplankton species. The reasons for the differences in species variety and size composition between zooplankton of temperate and tropical regions is perhaps due to a number of factors. These include the effects of high and uniform temperatures, food availability and predation by fish and invertebrates.     

Anthropophagy and aggregation behaviour of the sandfly Phlebotomus argentipes in Sri Lanka

ABSTRACT. The visceral leishmaniasis (VL) vector Phlebotomus argentipes Annandale & Brunetti is widely distributed throughout the Indian sub-continent and S.E. Asia. The absence of VL in areas such as Sri Lanka has been attributed to the zoophilic nature of P.argentipes , since they were not recorded biting man.
Field studies on P. argentipes were undertaken in the central highlands of Sri Lanka, near Kandy, in May 1988. Male sandflies outnumbered females on cows by 19:1, and were regularly spaced at all densities. This behaviour is considered analagous to swarming in other Nematocera. However, all-night human-biting catches show the biting rate to be similar (mean=8.4, range 2–25 bites per night over ten consecutive nights) to that in N.E. India where VL is endemic. This anthropophagy was maintained during laboratory colonization.     

Movements of some indigenous riverine fish in Sri Lanka

The migratory movements of reproductive potamodromus fish established in man-made tropical lakes in the dry zone of Sri Lanka were determined. It was shown that the nine indigenous riverine species do not spawn in these lakes but move into the upstream channels when sexually mature. The pattern of upstream movement was found to be species-specific although most species showed a diurnal periodicity. It is suggested that the development of totally lacustrine forms of riverine species is very unlikely to occur in the man-made lakes of Sri Lanka because of their relatively short duration time.     

Helicobacter pylori in School Children From the Western Province of Sri Lanka

Background. Little is known about the prevalence of Helicobacter pylori in Sri Lanka and nothing is known about its prevalence in children. Therefore the prevalence of H. pylori in a group of school children in Sri Lanka was determined. Materials and Methods. The presence of H. pylori colonisation was determined by detection of faecal antigen and salivary antibody (IgG) by enzyme immuno assay, in 184 children aged between 5 and 19 years, in the Western Province‐Colombo district of Sri Lanka. Results. Overall, only 12/184 (6.5%) had detectable H. pylori antigen in their stools and were considered infected with H. pylori, while 51/184 (27.7%) had H. pylori IgG in saliva. H. pylori salivary IgG declined with age while H. pylori antigen detection increased with age. H. pylori infection, as determined by salivary antibody (66%), was greater in children living in overcrowded conditions, although this was not statistically significant. Conclusion. The prevalence of H. pylori among school children in Sri Lanka was 6.5% by detection of faecal antigen and 27.7% by detection of salivary antibody, respectively. Initial infection with H. pylori appeared to occur in early childhood whilst active disease began in late childhood. Overcrowding appears to facilitate the transmission of the organism. Overall the prevalence of H. pylori was low in Sri Lanka compared with other countries in South‐east Asia.     

Constraints to the implementation of biological control in Sri Lanka

Sri Lanka is a tropical island with a rich diversity of arthropods, with many species of indigenous natural enemies of economic pests. However, no extensive island wide surveys have been carried out for natural enemies of major crop ecosystems and only a few of the indigenous natural enemies are reported useful for augmentation biological pest control by massive field releases of laboratory-produced insects. Most successful biological control programs on the island are importation (i.e. classical) biological control programs, where established exotic natural enemies control certain pest populations in valuable crops. There is growing interest in the use of native natural enemies in pest management, thus creating a need for intensive research on the ecology of indigenous natural enemies and development of infrastructure and technology to produce natural enemies for augmentation. This paper examines constraints and opportunities for implementation of biological control in Sri Lanka.     

Seasonality of mortality in Sri Lanka: Biometeorological considerations

The seasonal variation of mortality in Sri Lanka was studied in relation to meteorological variables. Time series data of the total monthly number of deaths in men and women from 1976 to 1980 were analyzed by power spectrum analysis of the fast Fourier transformation method in the areas of Colombo (lowland area, altitude 7 m) and Nuwara-Eliya (highland area, altitude 1890 m), respectively. In the Colombo area, where the mean temperature was always high (mean, 27.5 °C), a seasonal variation in mortality of 6 months was validated by power spectrum analysis with peak times in June and November. These mortality peaks corresponded to those of the amounts of rainfall which also showed an identical predominant period of 6 months. In the Nuwara Eliya area, where the mean temperature was always low at about 15–16 °C, a seasonal variation of approximately 3 months was found in addition to the 6 months' periodicity. The comparison of the power spectrum pattern of mortality with those of meteorological variables suggested that the amount of rainfall was associated with the seasonal variation of mortality in the Nuwara-Eliya area. In conclusion, the seasonality of mortality in Sri Lanka, a typical tropical zone country, was related to seasonal variation in the amount of rainfall, or a humidity factor, but not to mean temperature.     

Elemental concentrations in a tropical montane rain forest in Sri Lanka

As a preliminary to studies on biogeochemistry of a tropical montane rain forest at about 1800 m altitude in Sri Lanka, the concentrations of 17 chemical elements in different forest compartments, i.e. in leaves of six floristically dominant tree species, undergrowth, litter, and soil at 0–10 cm and 11–60 cm depth were determined. Foliar chemical differences between species were large. Mean leaf water content, mean leaf area per leaf, and specific leaf weight of each species were also determined. Calcium seems to be used in relatively large quantities by these plants. Phosphorus concentration in all compartments was consistently low. A few species investigated appeared to concentrate aluminium and silicon at high amounts. Concentration differences between compartments were significant only for certain elements. Location effect on the concentrations in soil was considerable for most of the elements studied. When studying plant-soil chemical interactions in these forests, species-level concentrations must be taken into account as the species-specific chemical differences are obscured when treated as canopy leaves.     

Karyosystematic studies onRubiaceae: Chromosome counts from Sri Lanka

Chromosome numbers for 16 different taxa ofRubiaceae from Sri Lanka are presented. Counts for 13 species, including 5 genera and 1 tribe, are new. The results are listed, compared with available literature data and discussed in regard to their systematical importance.     

Anti-Rhinosporidial Antibody Levels in Patients with Rhinosporidiosis and in Asymptomatic Persons,in Sri Lanka

The only report hitherto, from India in 1982, on anti-rhinosporidial antibody levels in patients with rhinosporidiosis recorded that antibody was not detected in Indian patients. The present report describes the use of the dot-ELISA assay of serum anti-rhinosporidial IgG, IgM and IgA and salivary sIgA in patients with diverse clinical presentations, in rural asymptomatic persons who had bathed in ground waters that probably harboured the causative pathogen, Rhinosporidium seeberi, and in laboratory persons who were exposed to R. seeberi. Ultrasonic extracts of purified endospores and sporangia of R. seeberi were used as antigen. The geometric mean (reciprocal) titres of serum antibody detected in patients were IgM 142.1, IgG 178.5, IgA 84.6, with ranges of 0-640, 30-960 and 0-160 respectively, salivary sIgA titres ranged from 0 to 18 with a mean of 4.6. The levels of antibody had no correlation with the site, the number of sporangia, duration and recurrence of the disease. Asymptomatic persons from the same endemic area as patients showed mean titres of IgM 89.6, IgG 69.1, IgA 95.5, with salivary sIgA titres of 3.1. Asymptomatic personnel who had been working in a laboratory where rhiniosporidial work was being done, showed mean titres of 169.6 IgM, 62.8 IgG, and 6.5 salivary sIgA. These results indicate that an anti-rhinosporidial antibody response occurs in rhinosporidial patients, as well as in asymptomatic persons who were exposed to R. seeberi in the environment. Anti-R. seeberi antibody does not appear to be protective in rhinosporidiosis since appreciable titres were present in patients with recurrent, single, multiple or disseminated lesions of long duration.     

Sublineages of Beijing Strain of Mycobacterium tuberculosis in Sri Lanka

Strains of the Beijing/W genotype of Mycobacterium tuberculosis have been responsible for large outbreaks of tuberculosis around the world, sometimes involving multi-drug resistance. It has been shown that more recently evolved Beijing sublineages are prone to cause outbreaks. Furthermore Beijing is the single predominant cluster in Sri Lanka. The present study identifies that recently evolved sublineages of Beijing strains are present in the study population. The majority of Beijing isolates (92.85%) were pan-susceptible. However, these findings may have important implications for the control and prevention of tuberculosis in Sri Lanka.     

A survey of glucose-6-phosphate-dehydrogenase deficiency in the North Central Province of Sri Lanka (formerly Ceylon).

A high frequency of the G6PD deficient gene was detected in the North Central Province of Sri Lanka. The frequency in the ancient villages is much higher than that of the recently colonised areas. The Sinhalese and Ceylon Moors have a significantly higher frequency as opposed to the Ceylon Tamils. The distribution appears to be related to a history of exposure to malarial endemicity.     

Relationship of environmental changes in central Sri Lanka to possible prehistoric land-use and climate changes

A radiocarbon-dated pollen-analysed peat sequence from the Horton Plains (> 2000 m a.s.l.), in central Sri Lanka, together with physical and chemical parameters (organic carbon, mineral magnetics, carbon isotopes and phytoliths), indicates major environmental changes during the last 24,000 years. The results suggest that a mobile life form, i.e. a hunter–forage culture, predominated in an open landscape, associated with xerophytic vegetation, e.g. Chenopodium spp. at  17.5 ka BP. Incipient management of cereal plants and slash-and-burn techniques seem to have prevailed between 17.5 and 13 ka BP, which was indigenous and associated with grazing. Evidence of systematic cereal cultivation in the form of oat and barley pollen grains is found from the late Pleistocene ( 13 ka BP). This is the earliest evidence of farming activities noted in Sri Lanka as well as in south Asia. After 13 ka BP, cereal cultivation was associated with an increase in humidity. With a later abrupt increase in aridity, agricultural land-use decreased from  8 to  3.6 ka BP, when the area appears to have been almost deserted. After a severe middle Holocene arid phase (i.e. 5.4–3.6 ka BP), the agricultural activity with a limited extension was again initiated by  2.9 ka BP. During the next  900 years, cultivation ceased allowing the upper montane rain forest to dominate. Between 0.2 and 0.15 ka BP, new phases of agricultural activities were undertaken and potato cultivation took place lately, between 1950 and 1969 AD.     

Vegetation survey of the Wasgomuwa National Park,Sri Lanka: analysis of the Wasgomuwa Oya Forest

Three types of forests were recognised (high, disturbed and open) based on the openings in the canopy in a Tropical Monsoonal Forest at the Wasgomuwa National Park, Sri Lanka. The analysis of these forests showed that the species composition varied between forest types. The shrub vegetation, not only was very characteristic but was also a major component in each forest, unlike in the tropical rain forest. The exact role of the shrubs in the dynamics of the tropical monsoon forests is not established, but is suggested that it may act as a buffer during the dry periods under a semi deciduous canopy. The sapling composition differed from the tree vegetation and indicated that the species composition may change with time in this forest. Mosaic theory or the patch dynamics may best explain the dynamics of this tropical monsoon forest which is a mixture of forest types. More studies are required before generalisations can be made of tropical monsoon forests.     

Bryophytes of Sri Lanka: a review of past exploration and taxonomic research and priorities for the future

This overview presents a historical summary of the past collectors of bryophytes (mosses, liverworts and hornworts) in Sri Lanka, formerly Ceylon, and some of the researchers who studied and published the results of their explorations. The first British collectors of the early nineteenth century were linked with the development of the Botanic Garden and herbarium in Peradeniya, of which George Gardner and George Thwaites made the greatest contributions, resulting in three publications by William Mitten on both mosses and liverworts. By the mid-nineteenth century, collectors from other countries took the lead, firstly Johannes Nietner from Germany and Odoardo Beccari from Italy. By the early twentieth century, Victor Schiffner from Austria and Max Fleischer from Germany became the leading bryologists throughout SE Asia, and both visited Ceylon. Fleischer’s work was part of a monographic revision of all mosses resulting in many new genera and species. After Fleischer, the most important bryologist was the German Theodor Herzog, who was the first to describe the ecological structure and bryological richness of different forest zones in southern Ceylon, with insight into forest loss from agricultural and population expansion, and a summary of biogeographical links of the bryoflora. The English bryologist H.N. Dixon took over from Mitten in describing many new moss species. Since independence in 1948, bryology in Sri Lanka has had major input from some local bryologists, such as B.A. Abeywickrama, as well as several important visitors, notably H. Inoue from Japan, C.C. Townsend from England, P.P.M. Tixier from France, and Maurice Onraedt from Belgium. Awareness in Sri Lanka of the need to taxonomically revise the extensive and scattered herbarium collections, has led to the running of some bryophyte workshops and training of new Sri Lankan bryologists. The ultimate goal of these efforts is to produce the first comprehensive bryophyte flora of the country, and priorities for future work are outlined.     

Nontimber forest product gathering in Ritigala forest (Sri Lanka): Household strategies and community differentiation

Sri Lanka has a long tradition of forest product use. The relationship of people with a dry zone forest was studied using a sample of 48 households in two villages that varied in distance to the forest and access to the market. All households interviewed collected subsistence forest products and a majority of them also collected commercial products. The daily peak-season income from commercial gathering was 4.5 to 7.7 times the daily labor wage. There is a strong gender specialization, with commercial gathering dominated by men whereas subsistence gathering is almost exclusively the task of women. The average forest-derived household income in the village closer to the forest and with better market access was nearly double that of the other village. Family size as a proxy of labor availability was the main discriminating factor between those households who did and those who did not gather commercial products. A small inverse relationship between forest gathering and size of household agricultural land (particularly paddy rice) was observed. No clear relationship was found between total household income and forest derived income, contradicting the view that commercial forest gathering is an exclusive activity of the poorest households.     

Some aspects of photosynthetic characteristics in a set of perennial irrigation reservoirs located in five river basins in Sri Lanka

Phytoplankton primary productivity of eleven irrigation reservoirs located in five river basins in Sri Lanka was determined on a single occasion together with light climate and nutrient concentrations. Although area-based gross primary productivity (1.43–11.65 g O₂ m^–2 d^–1) falls within the range already established for tropical water bodies, net daily rate was negative in three water bodies. Light-saturated optimum rates were found in water bodies, with relatively high algal biomass, but photosynthetic efficiency or specific rates were higher in water bodies with low algal biomass, indicating nutrient limitation or physiological adaptation of phytoplankton. Concentrations of micronutrients and algal biomass in the reservoirs are largely altered by high flushing rate resulting from irrigation release. Underwater light climate and nutrient availability control the rate of photosynthesis and subsequent area-based primary production to a great extent. However, morpho-edephic index or euphotic algal biomass in the most productive stratum of the water column is not a good predictor of photosynthetic capacity or daily rate of primary production of these shallow tropical irrigation reservoirs.