Late Rainy Season Research Articles

Evaluation of male reproductive hormones of Kalahari Red and Kalawad goat bucks as affected by age and season under tropical conditions.

Comprehensive understanding of reproductive hormones and environmental cues with their relationship is essential for efficient production in livestock sectors involving either assisted or natural reproductive methods. This study evaluated the effects of age and seasonal-associated changes in the blood concentrations of testosterone and follicle stimulating hormone (FSH) of male Kalahari Red (KR) andKalawad(KW)-crossbred goats. Based on a 2 × 3 × 4 factorial arrangement, a total of 42 bucks (KR n = 21 and KW n = 21) were allotted into three age groups (> 1 ≤ 2years, > 2 ≤ 3years and > 3 ≤ 4years) with seven KR bucks and seven KW bucks each per age group; reared under different seasons (early rainy, late rainy, early dry and late dry). The animals were managed semi-intensively, kept in an open-ventilated pen and subjected to same nutritional regime throughout the one-year experimental period. Follicle stimulating hormone and testosterone concentrations were analyzed in serum samples. Data obtained reproductive hormones were subjected to three-way Analysis of Variance using SAS 1999. Results show that breed had a significant effect (p < 0.05) on both serum FSH and testosterone concentrations. The highest FSH (0.49 ± 0.02ng/mL, 0.45 ± 0.01ng/mL, 0.41 ± 0.1ng/mL and 0.47 ± 0.07ng/mL) mean values (P > 0.05) were observed in KR in September, October, November and May, respectively while the highest (2.6 ± 0.02ng/mL) testosterone concentration in KW (p < 0.05) was obtained in December. Testosterone had irregular patterns between breeds and months of sampling. FSH was at peak (p > 0.05) in KR during the late rainy season at all ages while the values of FSH concentration in KW were not significantly different at all ages and seasons. The highest (2.05 ± 0.11ng/mL) serum testosterone mean value in KW peaked (p < 0.05) age > 3 ≤ 4years during the late rainy season. Testosterone concentration was lower and steady at all ages during rainy seasons in KR but started fluctuating during the early dry season. The least mean (0.62 ± 0.07ng/mL and 0.68 ± 0.05ng/mL) were recorded (p > 0.05) in KW during the late dry season at age > 2 ≤ 3 and > 3 ≤ 4years respectively. In KR and KW goat breeds raised under tropical condition, the high seasonal variations were responsible for the fluctuations in the reproductive hormones which resultantly altered or lowered the sexual activity of the animals at certain season(s).

Dormancy of a specialist herbivore, Anthonomus rufipennis (Coleoptera: Curculionidae), in a dry tropical forest.

The life history aspects of dormancy of the weevil Anthonomus rufipennis LeConte (Coleoptera: Curculionidae) were studied a 57-month period in a seasonally dry tropical forest of central Mexico. Weevil populations and their physiological status were monitored on both the reproductive host tree, Senna polyantha (Collad.) H.S: Irwin & Barneby (Fabales: Fabaceae) and the highly favored refuge host, Tillandsia recurvata L. (Poales: Bromeliaceae) or "ball moss." During the dry season, weevils were only found on the refuge host with a mean total density of 1.014 ± 2.532 individuals/ball moss (N = 1,681). Weevil densities on T. recurvata between early and late dry seasons were not significantly different, suggesting that dry season survival was relatively high. Weevils collected during these seasons revealed little reproductive development and relatively high-fat accumulation in both sexes. During 5 of 6 yr, densities of the weevils in T. recurvata dropped significantly during the early rainy seasons, when the reproductive host trees leafed out and began producing oviposition sites (flower buds). At this time, more males than females initially moved to vegetative trees and showed significant signs of reproductive development. Recolonization of ball moss by weevils began during the late rainy season when oviposition sites (flower buds) were still available. A proportion of the weevils remained on the reproductive host, suggesting that A. rufipennis is facultatively multivoltine. The methodologies and results of the study can serve as a model system for future studies of the dormancy of other insects in dry tropical forests and provide insight into the dormancy of other anthonomine weevils of economic importance.

On the importance of plant phenology in the evaporative process of a semi-arid woodland: could it be why satellite-based evaporation estimates in the miombo differ?

Abstract. The miombo woodland is the largest dry woodland formation in sub-Saharan Africa, covering an estimated area of 2.7–3.6 million km2. Compared to other global ecosystems, the miombo woodland demonstrates unique interactions between plant phenology and climate. For instance, it experiences an increase in the leaf area index (LAI) during the dry season. However, due to limited surface exchange observations in the miombo region, there is a lack of information regarding the effect of these properties on miombo woodland evaporation. It is crucial to have a better understanding of miombo evaporation for accurate hydrological and climate modelling in this region. Currently, the only available regional evaporation estimates are based on satellite data. However, the accuracy of these estimates is questionable due to the scarcity of field estimates with which to compare. Therefore, this study aims to compare the temporal dynamics and magnitudes of six satellite-based evaporation estimates – the Topography-driven Flux Exchange (FLEX-Topo) model, Global Land Evaporation Amsterdam Model (GLEAM), Moderate-Resolution Imaging Spectrometer (MODIS) MOD16 product, operational Simplified Surface Energy Balance (SSEBop) model, Thornthwaite–Mather climatic Water Balance (TerraClimate) dataset, and Water Productivity through Open access of Remotely sensed derived data (WaPOR) – during different phenophases in the miombo woodland of the Luangwa Basin, a representative river basin in southern Africa. The goal of this comparison is to determine if the temporal dynamics and magnitudes of the satellite-based evaporation estimates align with the documented feedback between miombo woodland and climate. In the absence of basin-scale field observations, actual evaporation estimates based on the multi-annual water balance (Ewb) are used for comparison. The results show significant discrepancies among the satellite-based evaporation estimates during the dormant and green-up and mid-green-up phenophases. These phenophases involve substantial changes in miombo species' canopy phenology, including the co-occurrence of leaf fall and leaf flush, as well as access to deeper moisture stocks to support leaf flush in preparation for the rainy season. The satellite-based evaporation estimates show the highest agreement during the senescence phenophase, which corresponds to the period of high temperature, high soil moisture, high leaf chlorophyll content, and highest LAI (i.e. late rainy season into the cool-dry season). In comparison to basin-scale actual evaporation, all six satellite-based evaporation estimates appear to underestimate evaporation. Satellite-based evaporation estimates do not accurately represent evaporation in this data-sparse region, which has a phenology and seasonality that significantly differ from the typical case in data-rich ground-truth locations. This may also be true for other locations with limited data coverage. Based on this study, it is crucial to conduct field-based observations of evaporation during different miombo species phenophases to improve satellite-based evaporation estimates in miombo woodlands.

Interdecadal change in the relationship between the South China late rainy season rainfall and equatorial Pacific SSTs

Abstract The South China (SC) late rainy season rainfall (SCLR) is important to people’s livelihoods and properties of this densely populated and economically developed region. Based on observation and reanalysis datasets, this study identifies that the relationship between the SCLR and equatorial Pacific SSTs (EPSSTs) experiences an interdecadal change around the late 1970s. The SCLR is negatively correlated with the eastern EPSSTs during 1948–1977 (the previous epoch) but positively correlated with the central EPSSTs during 1978–2022, especially during the last three decades 1993–2022 (the post epoch). This is due to the interdecadal change in El Niño flavors and EPSSTs-tropical Atlantic SSTs (TASSTs) relationship. With the increasing frequency of central Pacific El Niños in the post epoch, the El Niño-related warm SST anomaly center shifts from the eastern equatorial Pacific (EEP) to the central equatorial Pacific (CEP). Correspondingly, the anomalous cyclone exerted by the CEP warming reaches SC and causes rainfall surplus there (westward propagation pathway). In contrast, the EEP warming in the previous epoch can’t influence the SCLR through the westward propagation pathway, but through shifting the westerly jet southward via heating the tropical troposphere. The southward shifted westerly jet crashes the Qinghai-Tibet Plateau, triggering cyclonic circulations across the northern East Asia and North Pacific, which in turn cause anticyclonic circulations over the western SC and reduce SC rainfall (eastward propagation pathway). On the other hand, the CEP warming in the post epoch barely influence the SCLR through the eastward propagation pathway because of the enhanced negative relationship between EPSSTs and TASSTs.&amp;#xD;

Use of native and human-modified habitats by different mammal guilds in West Africa

Over millennia, mammals have coexisted with humans across the forest-savannah mosaics characterising part of West Africa. While some savannahs have long been used for rice cultivation in Guinea-Bissau, savannas and forests are now being rapidly converted into cashew monocultures. To understand how species cope with such land-use changes, we investigated how mammals make use of forest patches, cashew orchards and rice paddies over two contrasting periods: early and late rainy season. Using camera-trapping, we examined mammal diversity and trophic guild activity across seven landscapes, each with one sampling site per habitat type in Northern Guinea-Bissau. Based on 937 records from 21 species, species richness and activity were similar across habitat types, but generally higher in the late-rainy season. In this season, species composition differed between the cashew orchards and rice paddies. At the guild-level, carnivore activity was lower in the rice paddies than in forests, while herbivore activity was lower in the cashew orchards in comparison to that in forests in the early-rainy season. The relatively similar assemblage-wide diversity across habitat types seems to be enabled by the high habitat heterogeneity, but likely offset by previous extinctions from the area. Yet, guild-level habitat use highlighted the fundamental role of forests to sustain functionally healthy mammal assemblages. Maintaining habitat heterogeneity, including patches of native forests, seems to be key in optimizing the long-term conservation of mammal diversity in rural West Africa.

Relationship Between Fine Root Biomass and Soil Physico-chemical Properties of Grassland Ecosystem in Bhadrapur Municipality of Jhapa district, Eastern Nepal

This study investigated the distribution of fine root biomass and various soil properties in a grassland ecosystem within Bhadrapur Municipality, Nepal. Soil samples were systematically collected from randomly selected blocks in undisturbed, disturbed, and roadside areas during the late rainy season. Analyses included soil texture, moisture content, temperature, pH, and quantification of fine root biomass (FRB; &lt;5 mm diameter) within the top 15 cm soil depth. Results showed the mean FRB was significantly higher in undisturbed areas (7.77 t/ha) compared to disturbed (7.053 t/ha) and roadside (1.76 t/ha) areas. Across all sites, FRB exhibited a positive correlation with soil moisture content. Soil pH was slightly more acidic in undisturbed versus disturbed and roadside areas. Soil temperature demonstrated a positive correlation with FRB in undisturbed and roadside areas but a negative correlation in disturbed areas. Additionally, FRB negatively correlated with sand content in disturbed and roadside areas. The findings highlight how soil moisture is a key driver of fine root proliferation in this grassland ecosystem. Variations in soil texture, pH, and temperature between sites reveal their influence on root growth dynamics. Understanding these root-soil interactions has implications for sustainable grassland management, biodiversity conservation, and ecosystem resilience under changing environmental conditions.

Numerical assessment of changes in land–atmosphere interactions during the rainy season in South America using an updated vegetation map

AbstractLand Use and Land Cover Change (LULCC) is a key driver of changes in land–atmosphere interactions, playing an essential role in climate and weather patterns in South America (SA). This study used a modelling approach to assess the land–atmosphere changes introduced by LULCC over the Brazilian territory. Numerical experiments of early (2006), neutral (2004) and late (2008) rainy season onset years were performed in the Integrated BIosphere Simulator (IBIS) to assess the land‐surface parameters, and in Brazilian Atmospheric Model (BAM) to assess the atmospheric variables. The models were run with a natural (NAT) vegetation map and an updated (UP) vegetation map, which incorporated realistic Brazil deforestation up to the early 2000s. The differences between the two maps were particularly larger over 25°–15°S and 50°–40°W, where the Atlantic Forest and Cerrado biomes were replaced by pasture. IBIS experiments showed that over the area of larger LULCC there was an increase in albedo of up to 8% while reductions in net radiation, surface heat fluxes, surface temperature and surface roughness were noticed. Land–atmosphere feedbacks assessed with BAM experiments showed that LULCC contributed to a drier and colder (stable) atmosphere over central‐east SA that opposes the necessary conditions for the rainy season onset. The changes included increases in surface pressure and low‐level wind associated with reductions in 2 m temperature and surface roughness. These changes contributed to decrease the cloud formation and less precipitation in all three rainy season onset years, but particularly in the late rainy season onset year during September–October–November (SON). The atmospheric changes induced by LULCC show a pattern of dry atmosphere (reduced precipitation), similar to those of late onset years, and indicate that LULCC enhances the late rainy season onset condition over central‐east SA. Additionally, this study highlights the importance of considering up‐to‐date vegetation maps because these changes significantly affect both surface and atmospheric variables.

Machine learning system to assess rice crop change detection from satellite-derived RGVI due to tropical cyclones using remote sensing dataset

Tropical cyclones strike massive devastation of agricultural crops in South Asian countries practically every year. For assessing impacts on primary land use and land cover (LULC) classes of Patuakhali district in Bangladesh, this study utilized the Landsat-8 image dataset to compute change detection indices of a consistent cyclone landfall period in the late rainy season (October and November). Different stage of cyclones based on their wind speed (km/h) were also analyzed to explore agricultural crop change detection due to the tropical cyclone (TC) Bulbul (made landfall on November 9th, 2019). Three years later, cyclone Sitrang made landfall on October 24th, 2022, and was employed for the test results that the Bulbul's rice growth vegetation index (RGVI)-CD trained in the study's machine learning (ML) system. Therefore, the objective of this study was to determine rice crop changes from RGVI due to a cyclone (Bulbul) to evaluate growth change status by another cyclone (Sitrang) using machine learning system. In Patuakhali district, the rice crops were damaged mainly and affected in classification as moderately changed detected (MCD) 26.07%, very changed detected (VCD) 48.83%, and extremely changed detected (ECD) 17.73% in total agricultural lands area (1548.93 km2). It was also significantly monitored for the rice crops to change as rice growth vegetation index (RGVI)-CD related to cyclone wind speed (km/h), DEM, distance from the rivers, and shorelines. From the result, the symmetric regression of coefficient (R2) of (i) linear regression, (ii) fine tree, (iii) support vector machine, (iv) ensemble boosted trees, and (v) trilayered neural network were obtained 0.735, 0.734, 0.737, 0.756 and 0.736 as good-fitted test outcomes respectively. Applying the five machine learning models that were created from cyclone Sitrang, it was discovered that the test set in this system was accurate to the observed forecast with acceptable RMSE and MAE values. Therefore, study can be helpful for researchers creating new damaged and yield loss area assessment policies to help TC-affected farming communities, especially rice growers, prepare an effective emergency response plan for their socioeconomic needs fulfillment in the changing climate perspectives for attaining sustainable development.

Effects of strain and season on incubation parameters of Nigerian local guinea fowls

The study was conducted to determine the effects of strain and season on incubation parameters of Nigerian local guinea fowls. A total of three thousand six hundred (3600) fertile eggs (400 eggs per strain in each of the three seasons; early rainy, late rainy and early dry) generated from 144 matured guinea fowls (120 guinea hens and 24 guinea cocks) were used to obtained the following parameters; number of eggs set (NOES), number of fertile eggs (NOFE), number of dead in shell (NODIS), number of eggs hatched (NOEH), fertility (%) and hatchability (%). Data generated for the study were subjected to multivariate analysis of variance (MANOVA) of SPSS 25 (2017) to determine the effects of season and strain on incubation parameters. The results of the study showed that Pearl strain had significantly higher (p&lt;0.001) NOFE (320.00), NODIS (36.00), NOEH (274.89), fertility (80.00 %) and hatchability (85.91 %). Season wise, late rainy and early dry seasons had significantly higher (p&lt;0.001) values on most incubation parameters observed. The interaction effect of strain and season on incubation parameters of guinea fowls was not significant, except on NOEH (p&lt;0.001) where estimates obtained for Pearl at late rainy and early dry seasons had the highest values, while the least were observed in Lavender during early rainy, late rainy and early dry periods. In conclusion, Pearl strain of Nigerian local guinea fowl had the best results for incubation parameters during late rainy and early dry seasons than white and Lavender types.

Seasonal Variation in Aeromycoflora of Satpuda Botanical Garden, Nagpur (M. S.), India

Airborne mycoflora disperse through the air and deposited on different surfaces and germinates causing many diseases into host on which they land. The study of aeromycoflora of particular area provides the clear view about interaction of fungal spores in the form of disease on plants. For better understanding of this phenomenon, a systematic Aeromycological survey of Satpuda Botanical Garden, Nagpur has been conducted employing Gravity plate method for late rainy season (Sept.-2018) and late winter season (Jan- 2019). During survey, altogether 3101 colonies have been recorded on nutrient agar jelly which was classified into and 39 species belonging to19 genera. A count of 2345 colonies has been recorded in the month of Jan-2019 while 756 colonies in the month of Sept. -2018. Increase in species diversity &amp; spores concentration was reported in late winter in January-2019 (2345 colonies) against late rainy season in September-2018 (756 colonies).

The role of sex hormones and ROS values in the control of andrology in male double-spurred Francolin (&lt;i&gt;Francolinus bicalcaratus&lt;/i&gt;)

Background: This study explored the relationship between andrology, seasonal sex hormone fluctuations, and ROS values in adult male Francolinus bicalcaratus while establishing baseline parameters.&#x0D; Methods: Double-spurred Francolins (n=5 per season) were randomly selected in both dry and rainy seasons from their natural habitat. They were carefully stabilized with dewormer, antibiotics, and multivitamins, then acclimatized for two weeks at the Experimental Animal House, University of Ibadan, Nigeria. The birds were weighed, sedated, and 3 to 5 ml of blood was collected from the jugular vein in lithium heparinized bottles for serum sex hormone analysis. Testes were excised, weighed, washed with a 1.15% KCL solution, and processed for complete andrology and oxidative stress assays.&#x0D; Results: Sperm count, activity, and morphological characteristics peaked during late rainy seasons, coinciding with increased mating and hatchability. This correlated with high serum testosterone and low ROS titres in the testes. Conversely, early dry seasons witnessed declines in serum testosterone, sperm parameters, and hatchability due to increased ROS titres from food scarcity. Late dry seasons saw further declines in sex hormone levels and elevated ROS titres, leading to the absence of sperm cells.&#x0D; Conclusion: This study highlights how sex hormone and ROS titres influence sperm cell viability in double-spurred Francolins, with significant seasonal variations. These factors mainly support spermatogenesis and fertility during the breeding season, characterized by food abundance and cover. Dry season sex hormone values serve as baselines, while wet season sperm count and ROS levels represent baseline data for this bird species.

A bioassay of mine-affected soils and ameliorants in semi-arid rehabilitation

Global restoration is a priority given the onset of the United Nations’ decade for restoration. It is challenging to restore arid lands from mining impacts, especially where topsoil deficits exist. Successful rehabilitation is essential for alternative land use after mining. This bioassay aimed to establish whether and why some combinations of iron ore mine-affected soils and ameliorants are more effective in promoting plant growth than others. We examined the responses of one thousand radishes (Raphanus sativus) to five mine-affected soils and four soil ameliorations (soil improvement using fertiliser and organic matter) over two different seasons (early and late rainy seasons). We found that soil characteristics affected plant production regardless of amelioration and that some soil/amelioration combinations were significantly better than others. Topsoil ameliorated by moderate fertiliser application produced the best results. Waste rock could support germination and plant production when ameliorated with certain organic compost and fertiliser combinations. Untreated mine-affected soils had low to no plant production. Plant responses to the different soil/amelioration combinations were affected by season. Our findings suggest that area-specific bioassay investigations and their results could improve management decisions to achieve rehabilitation targets for mine-affected soils.

Summer Extreme Precipitation in Southern China from the Perspective of Moisture Static Energy

Abstract The extreme precipitation (EP) in the early and late rainy seasons in Southern China is investigated from the perspective of moist static energy (MSE). At the synoptic time scale, the EP is accompanied by the charge–discharge paradigm of the vertically integrated MSE (〈MSE〉); the positive 〈MSE〉 anomaly reaches the peak one day before EP and decreases quickly during the event. The charge–discharge paradigm of 〈MSE〉 is dominated by the horizontal and vertical advection, respectively. However, synoptic systems responsible for the 〈MSE〉 charge in the early and late rainy seasons are different due to the different horizontal distributions of climatological MSE in the lower troposphere caused by the northward migration of solar radiation and the monsoon system. At the interannual time scale, more EP in the early (late) rainy season is associated with the higher seasonal-mean 〈MSE〉 that can be caused by the anomalous anticyclone (cyclone) in the western North Pacific induced by the SST anomalies in the tropical Indian Ocean and central North Pacific (the tropical Pacific). The multimodel ensemble mean of CMIP6 models reproduces well the observed 〈MSE〉–EP relationship in both the historical and Shared Socioeconomic Pathway 5–8.5 (SSP5–8.5) runs. Moreover, the mean state of 〈MSE〉 increases in the SSP5–8.5 compared to historical runs along with more frequent occurrence of EP events. Hence, 〈MSE〉 can serve as a useful metric for studying EP in Southern China at various time scales.

ANALYSIS OF IMPACT OF RAINFALL AND TEMPERATURE VARIABILITY ON MALARIA INCIDENCE IN YAMALTU/DEBA LOCAL GOVERNMENT OF GOMBE STATE, NIGERIA.

Despite significant advancements achieved in the last two decades in reducing the worldwide impact of malaria, the disease still poses a substantial public health challenge. Moreover, there exists a growing apprehension that climate change could potentially broaden the regions conducive to disease transmission. This research focuses on investigating the impact of climate variability on malaria incidence in the Yamaltu/Deba Local Government Area (LGA) of Gombe State, Nigeria, from 2013 to 2022. Precipitation and temperature records were sourced from the Upper Benue River Basin Development Authority’s Dadin-Kowa Meteorological station, while confirmed uncomplicated malaria cases were obtained from the Gombe State Primary Healthcare Development Agency.The study entails an examination of the relationship between climate variability and malaria incidence in the study area. Pearson’s product-moment correlation coefficient was employed for this purpose. Furthermore, time series analysis was conducted to assess trends in rainfall, temperature, and malaria cases. The findings revealed an increasing trend in both rainfall and malaria cases, while maximum and minimum temperatures displayed negligible decreases over the specified period. Notably, correlation analysis unveiled a positive relationship between rainfall and malaria, with an r value of 0.319. Conversely, maximum and minimum temperatures exhibited a strong negative correlation, with r values of -0.152 and -0.534, respectively. Seasonal analysis highlighted a greater prevalence of malaria cases during the late rainy season, specifically in the months of July and October. October emerged as the month with the highest recorded malaria cases, totaling 44,351 cases, while May exhibited the lowest number of cases at 15,488. Given these findings, it is recommended to prioritize vector control initiatives and raise public awareness regarding the effective implementation of intervention measures, such as indoor residual sprays. These efforts are especially crucial during peak periods characterized by favorable weather conditions to mitigate malaria outbreaks effectively.

A Comparative Analysis of the Synoptic Conditions of Two Heavy Rainfall Cases West of the Pearl River Estuary

This paper compares the synoptic-scale circulation and thermodynamic conditions of two representative heavy rainfall cases that were concentrated west of the Pearl River Estuary under different seasonal backgrounds. The first case occurred in the early rainy season, with strong precipitation lasting for several hours. The second case occurred in the late rainy season, with extreme flash downpour in just two hours. The analysis reveals that the main cause was different for the two rainfall cases. The main cause of the first rainfall case was converging polar cold air and marine warm air that formed a synoptic scale front that drove the strong ascent. The main cause of the second case was a cold backflow from the Taiwan Strait, resulting in a sharply contrasting equivalent potential temperature front and triggering very strong upward motion. The moist potential vorticity (MPV) showed a negative value before both rainstorms, indicative of the importance of convective instability. A sandwich-like configuration of the MPV led to the development of strong vertical motion for the second case.

Radial Growth–Climate Relationship Varies with Spatial Distribution of Schima superba Stands in Southeast China’s Subtropical Forests

To understand the impact of climate change on the tree radial growth in Southeast China’s subtropical evergreen broadleaved forest, comparative research on the radial growth–climate associations of Schima superba was conducted. This dominant evergreen broadleaved tree species was examined at both its southern and northern distribution margins through dendroclimatology. The results showed that the radial growth of S. superba stands at a high elevation in the southern margin and stands in the northern margin were positively correlated with springtime temperatures, mostly in April (e.g., mean temperature: r = 0.630, p &lt; 0.05) and May (e.g., maximum temperature: r = 0.335, p &lt; 0.05), respectively. Meanwhile, the temperature in the late rainy season had a significant negative effect on the radial growth of S. superba stands in the southern margin, including high-elevation stands (e.g., the mean temperature in previous and current September: r = −0.437 and −0.383, p &lt; 0.05) and low-elevation stands (e.g., the mean temperature in previous August and October: r = −0.577 and −0.348, p &lt; 0.05). It was shown that temperature was the key climatic factor affecting the radial growth of S. superba, and the response of radial growth to temperature had obvious spatial differences. The findings indicate that the radial growth of S. superba stands in warm growth environments will be negatively impacted by future climate warming. On the contrary, the radial growth of S. superba stands growing in relatively cold growth environments may benefit from warmer spring. The results enhance the understanding of tree growth responses to climate change in the subtropical forests of China.

The Influence of Nitrogen and Phosphorus Addition on Growth of the Invasive C4 Grass Saccharum spontaneum

Invasive C4 grasses can inhibit the natural regeneration of secondary forest in tropical landscapes after the cessation of intensive use for grazing and agriculture. In Panama, invasive Saccharum spontaneum forms dense stands that require active management to re-establish forest successional processes. In this region, restoration strategies typically involve clearing grass cover manually and applying fertilizer prior to planting tree seedlings. However, if fertilizers alleviate nutrient limitation and enhance grass competition with tree seedlings, these practices may exacerbate the costs of Saccharum control and hamper restoration goals. Here, we evaluated how S. spontaneum responds to nitrogen and phosphorus addition in the field to determine whether S. spontaneum is nutrient limited in this system. S. spontaneum was limited by both nitrogen and phosphorus, as revealed through increased foliar nutrient concentrations. S. spontaneum biomass was significantly greater in both nitrogen and phosphorus addition plots after both the first growth period (early rainy season) and second growth period (late rainy season), with stronger effects of nutrient limitation during the second growth period for both N limitation and N and P co-limitation. Nutrient limitation in S. spontaneum highlights a potential risk of fertilizer applications during restoration, agriculture, and agroforestry activities in which invasion of this aggressive weed is a challenge to land management.

Structure and Phenology of Herbaceous Stratum in the Sahelian Rangelands of Senegal

This study describes the structure and phenology of Sahelian rangelands during the rainy season. It was undertaken on a grazed plot and a fenced plot. Measurements were taken every 10 days over two rainy seasons between July and October 2018 and between August and October 2019. The measurements included the phenological stage, the vegetative and flowering height, the coverage, and the phytomass. The results showed that phytomass did not systematically differ between grazed and fenced plots. Flowering started as early as mid-July, but most of the plants flowered in early October. Flowering and fruiting occurred earlier (based on the number of days after the first rain) in the late rainy season (2019) than in the early one (2018). These stages reached their peak in October; senescence began in October. Vegetative height, reproductive height, and coverage were similar between the two years. Height peaks were similar, but they were reached earlier (based on the number of days after the first rain) in the late rainy season than in the early one. Coverage peaks were similar (59.8% in the early rainy season vs. 65.8% in the late one). Vegetative height (around 30 cm), reproductive height (around 36 cm), and coverage (around 60%) reached their maximum in October, but reproductive height was greater than vegetative height. These parameters were lower at the grazed site compared to the fenced site, and flowering started earlier at the grazed site. The pasture had a negative impact on coverage, height, and early flowering. Structure and phenology were more sensitive than to changes in rainfall between years. Phenology results will help determine the best time to harvest the phytomass (phytomass stock), as the nutritional quality of the forage is known to decrease after fruiting.

Assessment of Pollution Status of River Ajali in Enugu State Using water quality index

The physico-chemical and microbial examination of Ajali River in Ezeagu Local Government Area (LGA) of Enugu State, South-eastern Nigeria, were carried out to assess the characteristics of the water for potability. Water samples were collected from three sampling points, including the one close to the brewery effluent discharge into the river and two different points that were affected by non-point sources. Altogether, eighteen samples were collected for two years during the dry, early and late rainy seasons. The physico-chemical, as well as microbial analyses of the samples, were determined following the standard methods. Significant spatial and seasonal variations (p<0.05) were clear for some physico-chemical parameters such as pH, phosphate, and sodium. Mean values of the Water Quality Index (WQI) were: dry season (104.23±9.75); early rainy season (113.22±8.78) and the late rainy season (102.58 ± 11.15). All the values are above 100 showing that the calculated WQI in all the seasons is not good however after the addition of lime, boiling and filtering to increase the quality.

Lichen biomonitoring of seasonal outdoor air quality at schools in an industrial city in Thailand

Poor air quality in school environments causes adverse health effects in children and decreases their academic performance. The main objective of this study was to use lichens as a biomonitoring tool for assessing outdoor air quality at schools in the industrial area of Laem Chabang municipality in Thailand. Thalli of the lichen Parmotrema tinctorum were transplanted from an unpolluted area to nine schools in the industrial area and to a control site. The lichens were exposed for four periods in the dry, hot, early rainy, and late rainy seasons, for 90days each. The concentrations of 14 elements, including As, Cd, Co, Cr, Cu, Fe, Mn, Mo, Ni, Pb, Sb, Ti, V, and Zn, were determined using inductively coupled plasma‒mass spectrometry (ICP‒MS), and 8 physiological parameters were measured. The concentrations of all 14 investigated elements were clearly higher at the schools than at the control site. The contamination factors (CFs) suggested that 9 out of the 14 elements, including As, Cd, Co, Cr, Cu, Mo, Pb, Sb, and Ti, heavily contaminated the school environments, especially Pb, the concentration of which was 3 to 11 times higher than at the control site. The most polluted time was the hot season as evidenced by the investigated elements, and the least polluted time was the late rainy season. The pollution load indices (PLIs) demonstrated that schools in the inner and middle zones clearly had higher pollution loads than the schools in the outer zone during the rainy seasons, while the hot and dry seasons showed similar pollution levels in all zones. The vitality indices (VIs) showed that the lower lichen vitalities at most schools were observed during the dry season and at the schools in the inner and middle zones. Accordingly, the air performance indices (APIs) revealed that poorer air quality at most schools was found during the dry season and at the schools in the inner and middle zones. This study clearly showed that the transplanted lichen P. tinctorum was an effective bioindicator of air quality in school environments. The results illustrated that all studied schools were contaminated by air pollutants; therefore, improving air quality at the schools is crucial and should be an urgent issue for maintaining good health and may benefit children's academic achievements and careers in the long run.