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PubMed2003

Molecular systematic analysis reveals cryptic tertiary diversification of a widespread tropical rain forest tree.

The broad geographic range of many Neotropical rain forest tree species implies excellent dispersal abilities or range establishment that preceded the formation of current dispersal barriers. In order to initiate historical analyses of such widespread Neotropical trees, we sequenced the nuclear ribosomal spacer (ITS) region of Symphonia globulifera L. f. (Clusiaceae) from populations spanning the Neotropics and western Africa. This rain forest tree has left unmistakable Miocene fossils in Mesoamerica (15.5-18.2 Ma) and in South America ( approximately 15 Ma). Although marine dispersal of S. globulifera is considered improbable, our study establishes three marine dispersal events leading to the colonization of Mesoamerica, the Amazon basin, and the West Indies, thus supporting the paleontological data. Our phylogeographic analysis revealed the spatial extent of the three Neotropical S. globulifera clades, which represent trans-Andes (Mesoamerica+west Ecuador), cis-Andes (Amazonia+Guiana), and the West Indies. Strong phylogeographic structure found among trans-Andean populations of S. globulifera stands in contrast to an absence of ITS nucleotide variation across the Amazon basin and indicates profound regional differences in the demographic history of this rain forest tree. Drawing from these results, we provide a historical biogeographic hypothesis to account for differences in the patterns of beta diversity within Mesoamerican and Amazonian forests.

Africa↗
PubMed2000

The process-based stand growth model Formix 3-Q applied in a GIS environment for growth and yield analysis in a tropical rain forest.

Managing tropical rain forests is difficult because few long-term field data on forest growth and the impact of harvesting disturbance are available. Growth models may provide a valuable tool for managers of tropical forests, particularly if applied to the extended forest areas of up to 100,000 ha that typically constitute the so-called forest management units (FMUs). We used a stand growth model in a geographic information system (GIS) environment to simulate tropical rain forest growth at the FMU level. We applied the process-based rain forest growth model Formix 3-Q to the 55,000 ha Deramakot Forest Reserve (DFR) in Sabah, Malaysia. The FMU was considered to be composed of single and independent small-scale stands differing in site conditions and forest structure. Field data, which were analyzed with a GIS, comprised a terrestrial forest inventory, site and soil analyses (water, nutrients, slope), the interpretation of aerial photographs of the present vegetation and topographic maps. Different stand types were determined based on a classification of site quality (three classes), slopes (four classes), and present forest structure (four strata). The effects of site quality on tree allometry (height-diameter curve, biomass allometry, leaf area) and growth (increment size) are incorporated into Formix 3-Q. We derived allometric relations and growth factors for different site conditions from the field data. Climax forest structure at the stand level was shown to depend strongly on site conditions. Simulated successional pattern and climax structure were compared with field observations. Based on the current management plan for the DFR, harvesting scenarios were simulated for stands on different sites. The effects of harvesting guidelines on forest structure and the implications for sustainable forest management at Deramakot were analyzed. Based on the stand types and GIS analysis, we also simulated undisturbed regeneration of the logged-over forest in the DFR at the FMU level. The simulations predict slow recovery rates, and regeneration times far exceeding 100 years.

Journal Article↗
PubMed1990

Ozone, acidic rain and soil magnesium effects on growth and foliar pigments of Pinus taeda L.

Height and diameter growth, biomass accumulation and leaf pigment concentrations were measured in loblolly pine (Pinus taeda L.) seedlings grown in soil containing 12 or 35 microg Mg g(-1) and exposed from May to October to subambient, ambient, or twice-ambient ozone (O(3)), and to simulated acidic rain with a pH of either 4.0 or 5.3. At the end of one growing season, height and diameter growth of seedlings exposed to twice-ambient O(3) were not statistically different from those of seedlings exposed to subambient O(3). Biomass of all plant parts was reduced by 7 to 16% in response to increasing O(3) concentration. No statistically significant growth responses to rain chemistry or soil magnesium status were observed, and there were no statistically significant interactive treatment effects. Needle pigment concentrations were not significantly affected by rain chemistry or soil Mg status and there were no visible signs of injury to needles that could be attributed to O(3) stress or Mg deficiency. Concentrations of chlorophyll a and b, and carotenes were 23, 30 and 21% higher (P </= 0.05) respectively, in seedlings exposed to twice-ambient O(3) than in seedlings from the other ozone treatments. There were no interactive treatment effects on needle pigment concentrations.

Journal Article↗
PubMed2006

Rain forest promotes trophic interactions and diversity of trap-nesting Hymenoptera in adjacent agroforestry.

1. Human alteration of natural ecosystems to agroecosystems continues to accelerate in tropical countries. The resulting world-wide decline of rain forest causes a mosaic landscape, comprising simple and complex agroecosystems and patchily distributed rain forest fragments of different quality. Landscape context and agricultural management can be expected to affect both species diversity and ecosystem services by trophic interactions. 2. In Central Sulawesi, Indonesia, 24 agroforestry systems, differing in the distance to the nearest natural forest (0-1415 m), light intensity (37.5-899.6 W/m(-2)) and number of vascular plant species (7-40 species) were studied. Ten standardized trap nests for bees and wasps, made from reed and knotweed internodes, were exposed in each study site. Occupied nests were collected every month, over a period totalling 15 months. 3. A total of 13,617 brood cells were reared to produce adults of 14 trap-nesting species and 25 natural enemy species, which were mostly parasitoids. The total number of species was affected negatively by increasing distance from forest and increased with light intensity of agroforestry systems. The parasitoids in particular appeared to benefit from nearby forests. Over a 500-m distance, the number of parasitoid species decreased from eight to five, and parasitism rates from 12% to 4%. 4. The results show that diversity and parasitism, as a higher trophic interaction and ecosystem service, are enhanced by (i) improved connectivity of agroecosystems with natural habitats such as agroforestry adjacent to rain forest and (ii) management practices to increase light availability in agroforestry, which also enhances richness of flowering plants in the understorey.

Animals↗
PubMed1991

Ocular manifestations of onchocerciasis in a rain forest area of west Africa.

The epidemiology and natural history of onchocerciasis and its ocular complications in rain forest areas are poorly understood. The present study was conducted on a rubber plantation in a hyperendemic area in the rain forest of Liberia, West Africa, where 800 persons were examined. The prevalence of infection was 84% overall 29% had intraocular microfilariae, and 2.4% were blind in one or both eyes. Onchocerciasis was the cause of all binocular blindness and one-third of all visual impairment. Over half of the visual impairment caused by onchocerciasis was due to posterior segment diseases. Chorioretinal changes were present in 75% of people, and included intraretinal pigment clumping in 52% and retinal pigment epithelium atrophy in 32%. Atrophy of the retinal pigment epithelium was associated with increasing age and severity of infection. Intraretinal pigment was strongly associated with anterior uveitis. There was a strong correlation between uveitis and the inflammatory chorioretinal sequelae: retinitis, intraretinal pigment, subretinal fibrosis, and optic neuropathy. These findings indicate that considerable visual impairment associated with rain forest onchocerciasis is common and is due largely to chorioretinal disease.

Adolescent↗
PubMedDate not supplied

A mitochondrial DNA phylogeny indicates close relationships between populations of Lutzomyia whitmani (Diptera: Psychodidae, Phlebotominae) from the rain-forest regions of Amazônia and northeast Brazil.

Phylogenetic analysis of all 31 described mitochondrial (cytochrome b) haplotypes of Lutzomyia whitmani demonstrated that new material from the State of Rondônia, in southwest Amazônia, forms a clade within a lineage found only in the rain-forest regions of Brazil. This rain-forest lineage also contains two other clades of haplotypes, one from eastern Amazônia and one from the Atlantic forest zone of northeast Brazil (including the type locality of the species in Ilhéus, State of Bahia). These findings do not favour recognizing two allopatric cryptic species of L. whitmani, one associated with the silvatic transmission of Leishmania shawi in southeast Amazônia and the other with the peridomestic transmission of Le. braziliensis in northeast Brazil. Instead, they suggest that there is (or has been in the recent past) a continuum of inter-breeding populations of L. whitmani in the rain-forest regions of Brazil.

Animals↗
PubMed2006

Nutrient regulation of organic matter decomposition in a tropical rain forest.

Terrestrial biosphere-atmosphere CO2 exchange is dominated by tropical forests, so understanding how nutrient availability affects carbon (C) decomposition in these ecosystems is central to predicting the global C cycle's response to environmental change. In tropical rain forests, phosphorus (P) limitation of primary production and decomposition is believed to be widespread, but direct evidence is rare. We assessed the effects of nitrogen (N) and P fertilization on litter-layer organic matter decomposition in two neighboring tropical rain forests in southwest Costa Rica that are similar in most ways, but that differ in soil P availability. The sites contain 100-200 tree species per hectare and between species foliar nutrient content is variable. To control for this heterogeneity, we decomposed leaves collected from a widespread neotropical species, Brosimum utile. Mass loss during decomposition was rapid in both forests, with B. utile leaves losing >80% of their initial mass in <300 days. High organic matter solubility throughout decomposition combined with high rainfall support a model of litter-layer decomposition in these rain forests in which rapid mass loss in the litter layer is dominated by leaching of dissolved organic matter (DOM) rather than direct CO2 mineralization. While P fertilization did not significantly affect mass loss in the litter layer, it did stimulate P immobilization in decomposing material, leading to increased P content and a lower C:P ratio in soluble DOM. In turn, increased P content of leached DOM stimulated significant increases in microbial mineralization of DOM in P-fertilized soil. These results show that, while nutrients may not affect mass loss during decomposition in nutrient-poor, wet ecosystems, they may ultimately regulate CO2 losses (and hence C storage) by limiting microbial mineralization of DOM leached from the litter layer to soil.

Biodegradation, Environmental↗
PubMedDate not supplied

Raine syndrome associated with cytomegalovirus infection.

Intracranial calcification, periosteal proliferation and microcephaly, which represent the clinical features of the congenital cytomegalovirus infection, can also be seen in a rare disorder named Raine syndrome. This clinical entity has been reported in eight families so far. Here, we report a new patient with clinical features of the Raine syndrome associated with cytomegalovirus infection. Although this may be a chance association only, the condition raised the question of whether early intrauterine CMV infection may contribute to the Raine phenotype.

Abnormalities, Multiple↗
PubMed2005

Constructed wetland attenuation of nitrogen exported in subsurface drainage from irrigated and rain-fed dairy pastures.

Nitrogen removal performance is reported for constructed wetlands treating subsurface drainage from irrigated and rain-fed dairy pastures in North Island, New Zealand. Flow-proportional sampling of inflow and outflow concentrations were combined with continuous flow records to calculate mass balances for the wetlands. Drainage flows from the irrigated catchment were 2.5-4 fold higher and N exports up to 5 fold higher per unit area than for the rain-fed catchment. Hydraulic and associated N loadings to the wetlands were highly pulsed, associated with rainfall, soil water status, and irrigation events. Transient pulses of organic nitrogen were an important form of N loss from the rain-fed landscape in the first year, and were very effectively removed in the wetland (> 90%). Median nitrate concentrations of approximately 10 g m(-3) in the drainage inflows were reduced by 15-67% during passage through the wetlands and annual nitrate-N loads by 16-61% (38-31 7 g N m(-2)y(-1)). Generation in the wetlands of net ammoniacal-N and organic-N (irrigated site) partially negated reduction in nitrate-N loads. The results show that constructed wetlands comprising 1-2% of catchment area can provide moderate reductions in TN export via pastoral drainage, but performance is markedly influenced by variations in seasonal loading and establishment/maturation factors.

Animals↗
PubMed2005

[Spatial and temporal pattern of Castanopsis fargesii seed rain in evergreen broad-leaved forest in Tiantong National Forest Park of Zhejiang, China].

Five mature plants of Castanopsis fargesii population were randomly chosen to study the spatial and temporal pattern of its seed rain in Tiantong National Forest Park, Zhejiang Province in 2003. The duration of seed rain observed from the five samples was about 45 days, from November 3rd to December 16th, with a distinguishable dropping peak between November 18th and 27th. The average seed rain density estimated from the traps deployed under the crown was 112.8 seeds.m(-2), ranging from 70 to 239.5 seeds.m(-2). Of the total acorns collected by seed traps, the viable accounted for 27.3%, the immature 25.7%, the eaten by rodents 5.0%, and the infected by larvae 42.0%. The acorns on the ground mainly distributed under the parent tree crown within 8 m from the trunk, and the spatial pattern of seed density on the ground fitted the quadratic distribution.

China↗
PubMedDate not supplied

Effect of artificial acid rain and SO2 on characteristics of delayed light emission.

The structure and function of chloroplast in plant leaves can be affected by acid rain and air pollution. The photosystem II in a plant is considered the primary site where light-induced delayed light emission (DLE) is produced. With the lamina of zijinghua (Bauhinia variegata L.) and soybean (Glycine max (L.) Merr.) as testing models, we studied the effects of artificial acid rain and SO2 on characteristics of DLE by using a home-made weak luminescence detection system. The results show that the changes in DLE intensity of green plants can reflect the changes in chloroplast intactness and function. With proper calibration, DLE may provide an alternative means of evaluating environmental acid stress on plants. The changes in DLE intensity may provide a new approach for the detection of environmental pollution and its impact on the ecosystem.

Acid Rain↗
PubMed2006

Role of simulated acid rain on cations, phosphorus, and organic matter dynamics in Latosol.

Acid rain is a serious environmental problem in the world and is of a particular concern in southern China where most of the soils are acidic. This study investigated the dynamics of cations, phosphorus (P), and soil organic matter (SOM) in the Latosol (acidic red soil) from south China under the influences of simulated acid rain (SAR). Laboratory experiments were performed by leaching the soil columns with SAR at pH levels ranging from 2.5 to 7.0 over a 21-day experimental period. Results show that about 34, 46, 20, and 77% of the original exchangeable soil Ca(+2), Mg(+2), K(+), and Na(+), respectively, were leached out by the SAR at pH 2.5 after 21 days. Two distinct patterns of the available phosphorus (AP) concentrations were observed: one at pH< or =3.5 and the other at pH > or = 4.0. At pH< or =3.5, concentrations of the AP increased from the beginning of the experiments to day 5, then decreased from day 5 to 15, and finally increased from day 15 to the end of the experiments. At pH > or = 4.0, concentrations of the AP increased consecutively from the beginning of the experiments to day 10 and decreased from day 10 to the end of the experiments. Such a finding is useful for agricultural practices since soil P is one of the most important macronutrients for plant growth. In general, SOM content decreased with time as the Latosol was leached by the SAR at all pH levels. A maximum concentration of soil fulvic acid was found after 15 days of the experiments due to the degradation of the SOM. A multiple regression analysis showed that a very strong relationship was obtained between the soil AP and the other three parameters (i.e., pH, SOM, and sorption P).

Acid Rain↗
PubMed2006

Seasonality of weather and tree phenology in a tropical evergreen mountain rain forest.

Flowering and fruiting as phenological events of 12 tree species in an evergreen tropical mountain rain forest in southern Ecuador were examined over a period of 3-4 years. Leaf shedding of two species was observed for 12 months. Parallel to the phenological recordings, meteorological parameters were monitored in detail and related to the flowering and fruiting activity of the trees. In spite of the perhumid climate of that area, a high degree of intra- and inter-specific synchronisation of phenological traits was apparent. With the exception of one species that flowered more or less continuously, two groups of trees could be observed, one of which flowered during the less humid months (September to October) while the second group started to initiate flowers towards the end of that phase and flowered during the heavy rains (April to July). As reflected by correlation coefficients, the all-time series of meteorological parameters showed a distinct seasonality of 8-12 months, apparently following the quasi-periodic oscillation of precipitation and related cloudiness. As revealed by power spectrum analysis and Markov persistence, rainfall and minimum temperature appear to be the only parameters with a periodicity free of long-term variations. The phenological events of most of the plant species showed a similar periodicity of 8-12 months, which followed the annual oscillation of relatively less and more humid periods and thus was in phase or in counter-phase with the oscillations of the meteorological parameters. Periods of unusual cold or dryness, presumably resulting from underlying longer-term trends or oscillations (such as ENSO), affected the homogeneity of quasi-12-month flowering events, fruit maturation and also the production of germinable seeds. Some species show underlying quasi-2-year-oscillations, for example that synchronise with the development of air temperature; others reveal an underlying decrease or increase in flowering activity over the observation period, influenced for instance by solar irradiance. As Ecuador suffers the highest rate of deforestation in South America, there is an urgent need for indigenous plant material for reforestation. A detailed knowledge of the biology of reproduction in relation to governing external factors (mainly climate) is thus required.

Altitude↗
PubMed2006

The influence of a coal-fired power plant in Turkey on the chemical composition of rain water in a certain region.

In this study, the chemical composition of the rainwater in Yatağan, which is a region surrounding a coal power plant was investigated from February to April 2002. Rainwater samples were obtained from Yatağan, located northwest of Muğla City in Turkey. pH values and concentrations of major ions (Ca(2+), Na(+), K(+), SO(2-)(4), NO(-)(3), NH(+)(4)) in the rainwater samples were analyzed. The pH varied from 5.1 to 7.9 with an average of 6.7 which was in alkaline range considering 5.6 as the neutral pH of cloud water in equilibrium with atmospheric CO(2). In the total of 30 rain events, only three events were observed with water in the acidic range (<5.6), which occurred after continuous rains. The equivalent concentration of components followed the order: Ca(2+) > SO(2-)(4) > Na(+) > NH(+)(4) > NO(-)(3) > K(+) > H(+). The anion and cation concentrations in the rainwater samples showed a high sulphate concentration (131 microEq/l), as well as high sodium (40 microEq/l) and calcium (298 microEq/l) concentrations. These values indicate that one probable source of the high sodium concentration is fly ash, after the coal burning process and the power plant can be effective on level SO(2-)(4) concentrations in rainwater. In addition, the dust-rich local and surrounding limestone environment might have caused the high concentration of Ca(2+) in rainwater of the Yatağan Basin. Due to a large contribution of these cations to the sulphate neutralization action, the rainwater of this region displays only a moderate acidity, which does not cause significant environmental impact.

Acid Rain↗
PubMed1993

A temporal analysis of rain-related crash risk.

The study presents empirical evidence of accident risk during and following rain events in the cities of Calgary and Edmonton, Canada. The matched sample approach is used to examine data for 169 rain events and over 15,000 accidents that occurred during the years 1979-1983. The overall accident risk during rainfall conditions was found to be 70% higher than normal. The data suggest that accident risk returns to normal as soon as the rainfall has ended, despite the lingering effects of wet road conditions.

Accidents, Traffic↗
PubMed1984

Effects of 2,4-dichlorophenoxyacetic acid in artificial acid rain on Brassica napus and Sinapis alba.

The effect of 2,4-dichlorophenoxyacetic (2,4-D) acid in artificial rain at pH 3.3 was examined for young plants of rape (Brassica napus L.) and white mustard (Sinapis alba L.). Plants were treated in a closed simulation chamber system with varying CO2 supply (198-418 ppm). Single or daily showers were applied for 20-30 min at varying 2,4-D concentrations (0, 0.03, 0.1, 0.5, and 2.5 mg liter-1). The plants were sampled 5 days after the last treatment. Epinasty was observed for Brassica at 0.5 mg liter-1 and for Sinapis at 0.1 mg liter-1 2,4-D. Leaf to stem dry weight ratios increased with increasing CO2 concentrations in the air and decreased following single treatments with 0.5 or 2.5 mg liter-1 2,4-D in the rain. Dose-effect relationships are proposed for both plant species. Leaf dry matter weights per area unit decreased with increasing CO2 concentrations, but were not significantly affected by the 2,4-D treatments.

2,4-Dichlorophenoxyacetic Acid↗
PubMed1989

Carcinogenic tryptophan pyrolysis products in airborne particles and rain water.

This is the first report that carcinogenic tryptophan pyrolysis products are present in airborne particles and rain water. The airborne particles were collected from August 1988 through October 1988 at 4 locations in Japan. The amounts of 3-amino-1,4-dimethyl-5H-pyrido[4,3-b]indole (Trp-P-1) and 3-amino-1-methyl-5H-pyrido[4,3-b]indole (Trp-P-2) in the air were 0.23 +/- 0.17 pg/m3 air (mean +/- SD, n = 18) and 0.16 +/- 0.15 pg/m3 air (n = 18), respectively. Moreover, these carcinogens were detected in rain water. These results indicate that Trp-P-1 and Trp-P-2 are ubiquitous environmental components.

Air Pollutants↗
PubMed1988

Relative contributions of late dry-season and early rains pasture contaminations with trichostrongyle eggs to the wet-season herbage infestation in eastern Nigeria.

Two worm-free grass paddocks, P1 and P2, were artificially contaminated in March and April-May, respectively, with bovine faeces containing known numbers of trichostrongyle (mainly Cooperia, Haemonchus and Trichostrongylus spp.) eggs in order to determine the relative contributions of late dry-season and early rains pasture contaminations to the wet-season herbage larval infestation in Nsukka, eastern Nigeria. The resulting herbage infestation was assessed by means of larval counts and tracer studies. A sudden rise in herbage infestation occurred simultaneously in both paddocks in late April, this apparently being determined by the onset of the first substantial rainfall of the wet season. Peak infestations in both paddocks also occurred simultaneously in May. The infestation in P1 was much larger, and the larval population persisted longer, than that in P2 and later gave rise to a second smaller peak in June. No L3 were recovered in herbage samples from either of the paddocks after the third week of July. Both paddocks were infective to goats in May-June, while P2 was also infective in July-August. The results suggest that in the Nigerian derived savanna the initial wet-season herbage infestation in pastures grazed by infected cattle during the dry and wet seasons will consist of L3 from late dry-season and early rains pasture contaminations, the former being the major contributor to the infestation. Consequently, pastures contaminated during the late dry season may not be safe for susceptible animals to graze at the start of the succeeding rainy season.

Ancylostomatoidea↗