Late Dry Season Research Articles

Effect of food limitation and reproductive activity on fecal glucocorticoid metabolite levels in banded mongooses

BackgroundGlucocorticoids mediate responses to perceived stressors, thereby restoring homeostasis. However, prolonged glucocorticoid elevation may cause homeostatic overload. Using extensive field investigations of banded mongoose (Mungos mungo) groups in northern Botswana, we assessed the influence of reproduction, predation risk, and food limitation on apparent homeostatic overload (n=13 groups, 1542 samples from 268 animals). We experimentally manipulated reproduction and regulated food supply in captive mongooses, and compared their glucocorticoid responses to those obtained from free-living groups.ResultsAt the population level, variation in glucocorticoid levels in free-living mongooses was explained by food limitation: fecal organic matter, recent rainfall, and access to concentrated anthropogenic food resources. Soil macrofauna density and reproductive events explained less and predation risk very little variation in glucocorticoid levels. Reproduction and its associated challenges alone (under regulated feeding conditions) increased glucocorticoid levels 19-fold in a captive group. Among free-living groups, glucocorticoid elevation was seasonal (occurring in late dry season or early wet season when natural food resources were less available), but the timing of peak glucocorticoid production was moderated by access to anthropogenic resources (groups with fewer anthropogenic food sources had peaks earlier in dry seasons). Peak months represented 12- and 16-fold increases in glucocorticoids relative to nadir months with some animals exhibiting 100-fold increases. Relative to the captive group nadir, some free-living groups exhibited 60-fold increases in peak glucocorticoid levels with some animals exhibiting up to 800-fold increases. Most of these animals exhibited 1- to 10-fold increases relative to the captive animal peak.ConclusionsBanded mongooses exhibit seasonal chronic glucocorticoid elevation, associated primarily with food limitation and secondarily with reproduction. Magnitude and duration of this elevation suggests that this may be maladaptive for some animals, with possible fitness consequences. In late dry season, this population may face a convergence of stressors (food limitation, agonistic encounters at concentrated food resources, evictions, estrus, mate competition, parturition, and predation pressure on pups), which may induce homeostatic overload.

A long-term assessment of fire regimes in a Brazilian ecotone between seasonally dry tropical forests and savannah

Abstract Fire is a recurrent phenomenon in semiarid seasonal ecosystems. The study of the relationship between fire and climate could provide new approaches for understanding fire dynamics in semiarid regions, which could be useful for strategically managing the loss and recovery of natural resources under threat. Here, we evaluated the patterns of fires occurrence in a semiarid Caatinga-Cerrado ecotone in the Northeast Region of Brazil by characterizing their spatiotemporal dynamics associated with climatic conditions. Using a temporal series of 306 Landsat images, we mapped a burned area database at a fine spatial resolution (30 m) from 1999 to 2017 in the Capivara-Confusoes Mosaic of protected areas and their surroundings. Fire seasonality was analyzed through climatic seasons, distinguishing between the rainy season (RS), early dry season (EDS), middle dry season (MDS) and late dry season (LDS), by analysis of the daily precipitation of ground-based stations in the area. We created yearly, seasonal and recurrence maps of burned areas to assess fire regimes. The results showed that the 48% of the area was burned during the 19-year long period considered. Serra das Confusoes National Park (SCoNP) had 302,644 ha burned, Serra da Capivara National Park (SCaNP) had 2056 ha burned and the ecological corridor had 215,718 ha burned. Most of the burned area was registered during the MDS (36% of the study area), there was almost no burned area in the EDS (

Seasonal movements and site utilisation by Asian water buffalo (Bubalus bubalis) in tropical savannas and floodplains of northern Australia

Abstract ContextThe Asian water buffalo (Bubalus bubalis) is an introduced herbivore of the savannas and floodplains of northern Australia. Despite the significant environmental damage caused by water buffalo, important cultural and commercial stakeholders request this species is managed rather than eradicated. However, gaps in knowledge of buffalo ecology limit effective policy and planning. AimsTo better understand how buffalo, at current population densities, respond to seasonally changing resources in the two key habitat types that they occupy in northern Australian – upland eucalypt savanna and seasonally inundated floodplain. MethodsSatellite telemetry was used to record the location of a single female buffalo from each of 11 independent clans every hour over a 12-month period. Generalised linear mixed modelling was used to assess the extent to which buffalo movements, activity-space and site revisitation correlated with forage quality (inferred from the normalised difference vegetation index – NDVI) and localised buffalo density. Key resultsAs the dry season progressed, forage quantity and quality within the activity-space of buffalo clans decreased. In response, buffalo inhabiting floodplain exhibited increased rates of movement and enlarged the size of their activity-space. This resulted in low repeated visitation of foraging areas in the late dry season and NDVI remained relatively high within these areas. In comparison, buffalo in upland savanna maintained similar rates of activity and occupied the same activity-space size throughout the year. This resulted in frequent revisitation of the same areas in the late dry season and NDVI reached as low as zero in these foraging areas. Clan size and localised buffalo density had no significant effect on measured movement parameters. ConclusionsBuffalo exhibited a behavioural strategy in upland savanna that resulted in acute removal of green herbaceous vegetation within a few kilometres of the clan’s permanent water source. Buffalo inhabiting the floodplain used multiple wallows that reduced grazing impacts, but likely resulted in hoof-derived impacts over a broad area. ImplicationsCurrent buffalo densities in Kakadu National Park appear to be well below carrying capacity but localised environmental degradation around permanent water sources remains severe in upland savanna.

‘We don’t want to drink that water’: cross-cultural indicators of billabong water quality in remote Indigenous Australia

Globally, many Indigenous people rely on surface waters for drinking due to limited access to safe or palatable water, cultural and spiritual reasons and belief in its healing properties. In northern Australia, Indigenous people from the remote community Ngukurr have raised concerns about drinking water from freshwater billabongs due to potential microbial contamination from feral ungulates (buffalo, pig, horse and cattle). In response to these concerns, a cross-cultural assessment of water quality and drinking water safety was undertaken. Indigenous biocultural indicators of water quality and perceptions of drinking water safety at billabongs were documented. In addition, Western scientific methods were used to assess billabong waters surrounding the Ngukurr community for the waterborne pathogens Cryptosporidium and Giardia. The results revealed that local Indigenous people make decisions about water quality and drinking water safety through visual indicators, seasonal knowledge and intuition. Giardia was only detected in the late dry season and Cryptosporidium was not detected during either the wet or dry season. The commonly held Indigenous perspective aligned with the pathogen results, whereby billabongs were safer to drink from in the early dry season then the late dry season. Boiling water when drinking from billabongs during all seasons is considered best practice to avoid ingestion of infective enteric pathogens.

Assessment of Surface Water Qualities in Ihetutu Mining Areas of Ishiagu, Nigeria, using Water Quality Index Model

The quality of surface water from rivers, streams and ponds around Ihetutu mining areas in Ishiagu, was evaluated using Water Quality Index (WQI) model, to assess their suitability for drinking purposes at different seasons. Surface water samples were collected in rainy, late rainy, dry and late dry seasons, from 10 cm below water surface of the streams, ponds, and mine pits into 1.0 L polyethylene bottles, rinsed thoroughly with deionized water. The samples were preserved at 4°C in an ice box and then transported to the laboratory for analysis. Samples were digested and analyzed, using standard methods for nine physico-chemical parameters including pH, Cl-, SO42-, NO3 -, DO, BOD5, Ca2+, Mg2+, K+. NESREA regulatory values for surface water were used as standard values while mean values of the physico-chemical parameters were used as observed values to determine the WQI for each sampling station. Ranges of the physico-chemical parameters were: pH = 6.52–7.49; Cl- = 13.70–795.25 mg/L; SO42- = 19.28-229.25 mg/L; NO3 - = 0.33–3.72 mg/L; DO = 5.72–8.76 mg/L; BOD5 = 12.19–18.20 mg/L; Ca2+ = 6.56–130.44 mg/L; Mg2+ = 2.06–20.89 mg/L; and K+ = 4.51-32.93 mg/L. Average and seasonal WQI values were found to be >100 which indicated that the surface water resources in the area were unsuitable for drinking, though Iyiogwe stream had a WQI value of 98 in the late dry season, indicating rather a very poor quality of its surface water. The results revealed that untreated mine wastewater, dumps, and other contaminants discharged from point and non-point sources into the rivers, streams, and ponds/pits were responsible for the extremely poor quality of the surface water, and must therefore be treated properly before use to avoid water related ailments. The study created a database for current status of surface water on Ihetutu hills, which can be used for the management of ponds/pits, stream and river water in the area, and the study of the impact of mining activities on the surface water qualities.

Seasonal fine fuel and coarse woody debris dynamics in north Australian savannas

Several studies have separately explored accumulation of the dominant fuels (grass, fine litter (<6mm diameter) and coarse woody debris (CWD, 6–50mm diameter)) in north Australian savannas. We report an analysis of two longitudinal datasets describing how these three fuel components covary in abundance throughout the year in eucalypt-dominated savanna over a rainfall gradient of 700–1700mm mean annual rainfall (MAR). Our observations concur generally with previous observations that litter accumulation results in a late dry season (LDS) peak in biomass, whereas cured grassy fuels typically are seasonally invariant, and CWD inputs are associated with stochastic severe wet season storms and dry season fires. The distinct LDS litter peak contributes significantly to the potential for LDS fires to be of higher intensity, burn more fuel per unit area and produce greater emissions relative to early dry season (EDS) fires. However, Australia’s current (2018) formal savanna burning emissions avoidance methodology erroneously deems greater EDS fine fuel (grass and fine litter) biomass in four of nine designated vegetation fuel types. The study highlights the need to develop seasonally dynamic modelling approaches that better account for significant seasonal variation in fine fuel inputs and decomposition.

Production and In Vitro Digestibility of Leucaena leucocephala Under Different Seasons and Planting Model Systems in Kupang Regency, Indonesia

Farmers in Kupang had 3 different Leucaena leucocephala plantations with each was planted under different local planting methods as their forage resource. In this research, we evaluate the production, nutritional content and in vitro digestibility of the L. leucocephala in all of the plantations during the early and late dry season as well as during rainy season. The first plantation was planted under Amarasi model (Amarasi plantation), where the L. leucocephala were planted in array; the second plantation was planted under Mamar Kering model (Mamar Kering plantation), where the L. leucocephala were planted by the natural fauna of the plantation; and the third plantation was planted under Selobua model (Selobua plantation), where the L. leucocephala were planted intercropping with crops. The harvest was done every four months from March 2016 to April 2017 by also following local harvesting practices (all of the branches and leaves were cut at 2-3 m above ground). The observed variables include dry matter (DM), organic matter (OM), crude protein (CP), neutral-detergent fiber (NDF), and acid detergent fiber (ADF) content, as well as the in vitro DM and OM digestibility of L. leucocephala . All of the obtained data were analyzed with nested ANOVA and followed with LSD test. The results showed that different planting model and season gave differences (P<0.01) to the DM, NDF, ADF, in vitro DM and OM digestibility. The study concluded that the Amarasi plantation had the highest production, while overall nutritional content and in vitro digestibility of L. leucocephala was better during rainy season, and the highest was found in Selobua plantation. Keywords: Amarasi, Mamar Kering, Selobua, forages, Leucaena leucocephala DOI : 10.7176/JBAH/10-2-05 Publication date: January 31 st 2020

Evaluation of Bottom Sediment Qualities in Ihetutu Minefield, Ishiagu, Nigeria

Bottom sediment qualities in Ihetutu minefield were assessed to ascertain the impact of Pb-Zn mining activities on the sediments from streams, rivers and ponds in the area. Levels of Cu, Zn, Fe, Ni, Mn, Pb, Cd and Cr and some physico-chemical parameters were measured in bottom sediments taken from four sampling stations (streams/mine pits) within Ihetutu minefield of Ishiagu which receives discharges from mining and human activities, and a control sampling station in Uturu (about 12 km away from study area). The study was conducted in four seasons (Rainy, Late Rainy, Dry, and Late Dry Seasons). Sample digestion was done with a temperature adjustable block digester. Heavy metal analysis was carried out with Flame atomic absorption spectrophotometer (FAAS) while other physico-chemical parameters were determined with standard field and laboratory procedures. Ranges of mean values of results obtained were; pH = 5.81 - 6.44, EC = 269.00 - 1545.00 μS/cm, Cl&#8722 = 43.30 - 112.33 mg/kg, alkalinity = 0.70 - 1.25 mg/kg, NO3- = 5.90 - 7.90 mg/kg, TOC = 0.81 - 1.75 mg/kg, TOM = 1.40 - 3.02 mg/kg, Cu = 4.74 - 50.93 mg/kg, Zn = 26.78 - 57.07 mg/kg, Fe = 1066.19 - 1764.05 mg/kg, Mn = 36.66 - 42.96 mg/kg, Ni = 4.02 - 17.19 mg/kg, Pb = 38.01 - 162.23 mg/kg, Cd = 1.01 - 25.90 mg/kg, and Cr = 1.23 - 1.62 mg/kg. Assessment of heavy metals pollution, using pollution indices revealed that Contamination factor ranged from moderate to very high degree of contamination while Pollution load index also showed a deterioration of bottom sediment qualities. Geoaccummulation index indicated moderate to very high pollution, especially with Cu, Zn, Pb, and Cd in the mine pit, while Enrichment factor indicated high enrichments and inputs from anthropogenic sources especially, the Pb-Zn mining activities. Pollution of the area by heavy metals was in the order of Fe > Pb > Zn > Mn > Cu > Ni > Cd > Cr. Highest positive correlation (r = 0.992) was between Pb and Cu while the highest negative correlation (r = &#87220.789) was between Ni and Mn. Analysis of variance (ANOVA) at significance level, α = 0.05, showed no statistically significant differences in the sampling stations (p > 0.05). Compared to background (control), DPR and other standard guidelines/values, bottom sediments from Ihetutu minefield were highly polluted with Pb, Zn and Cu especially at the mine site. The overall results from the study revealed that toxic substances released from the prolonged Pb-Zn mining activities in the study area have impacted negatively on the bottom sediments, thereby also possibly deteriorating the quality of lives of the bottom sediments dwelling organisms in the streams, rivers, and pits/ponds in the area.

Standing dead trees contribute significantly to carbon budgets in Australian savannas

Previous estimates of greenhouse gas emissions from Australian savanna fires have incorporated on-ground dead wood but ignored standing dead trees. However, research from eucalypt woodlands in southern Queensland has shown that the two pools of dead wood burn at similar rates. New field data from semiarid savannas across northern Australia confirmed that standing dead trees comprise about four times the mass of on-ground dead wood. Further, the proportion of total woody biomass comprising dead wood increases with decreasing fire frequency and a decreasing proportion of late dry season (August to December) fires. This gives scope for increasing the carbon stock in the dead wood pool with a reduced fire frequency. Following a previously published approach to quantify total dead wood loads in savannas, new and previously collected data on tree stand structures were used across the whole savanna zone to quantify dead wood loads in equilibrium with historic fire regimes. New parameters are presented for calculating dead wood dynamics including dead trees in Australia’s savannas.

Small mammal diversity is higher in infrequently compared with frequently burnt rainforest–savanna mosaics in the north Kimberley, Australia

Abstract ContextPopulations of native mammals are declining at an alarming rate in many parts of tropical northern Australia. Fire regimes are considered a contributing factor, but this hypothesis is difficult to test because of the ubiquity of fire. AimsThis preliminary study investigated relative abundance and richness of small mammals on a gradient of fire regimes in the Uunguu Indigenous Protected Area (north Kimberley, Australia). MethodsSpecies were sampled using 40 unbaited camera traps, positioned for a year on 20 transects crossing the rainforest–savanna boundary at locations with comparable environment and geology but varying fire history. The relative importance of the factors ‘fire frequency’, ‘late dry season fire frequency’, ‘time since burnt’ and ‘vegetation type’ as predictors of the number of small mammal species and detections was tested using Spatial Generalised Linear Mixed Models to account for spatial autocorrelation. Key resultsNine species of small mammals were observed. Mammals were more abundant and diverse in locations with low overall fire frequency, which was a better predictor than late dry season fire frequency or time since burnt. The model including fire frequency and vegetation explained the highest proportion of total variation in mammal diversity (R2=42.0%), with most of this variation explained by fire frequency alone (R2=40.5%). The best model for number of detections (R2=20.9%) included both factors. ConclusionsIn the north Kimberley, small mammals are likely to be more abundant and diverse in areas with low fire frequency. ImplicationsThis natural experiment supports the theory that frequent fires are contributing to the decline of small mammals observed across northern Australia.

The role of cross-border transhumance in influencing resident herders’ cattle husbandry practices and use of genetic resources

For centuries, the humid West African coastal country of Benin attracts cattle herders from neighboring Sahelian countries such as Niger, Burkina Faso and Nigeria. Each year, several thousands of cattle are trekked over hundreds of kilometers to Benin following established and non-established transhumance corridors. This cross-border mobility has been shown to play an important role in ensuring the productivity of the transhumant herds through adequate late dry season access to pastoral resources. Yet, its effects on the traditional agro-pastoral production systems that are encountered along the routes in Benin have never been explicitly investigated. Therefore, we collected socio-economic household data, herd characteristics and management data from 104 resident herders and 38 transhumant herders in 2 vegetation zones of Benin. To determine whether or not the proximity to transhumance corridors affects sedentary production systems, characteristics of cattle herds and farmers’ management practices were compared between villages close to (within a 25 km buffer) and far from (outside a 25 km buffer) transhumance corridors within and between vegetation zones using non-parametric statistical tests. Existing relationships between resident and transhumant herders were also identified and characterized. Subsequently, herd characteristics and management practices were compared between resident herders having relationships with transhumant herders and those without. Herd sizes of resident herders living close to transhumance corridors were larger (P < 0.01) than those of their counterparts living far away. Also, proximity to transhumance corridors had positive effects on herd management practices. The relationships between resident and transhumant herders were governed by a variety of interests including encampment/manuring contracts, exploitation of grazing lands and watering points, trading and bartering of cattle. This exchange of cattle is an important driver of change in the breed composition of local herds and represents an opportunity for resident herders to enhance their herds’ productivity through crossbreeding. However, the mere replacement or indiscriminate crossbreeding of local cattle breeds with those kept by transhumant herders threatens the sustainability of the traditional resident herding systems by increasing the risk of genetic erosion and loss of valuable adaptive traits in indigenous animal genetic resources.

Altitudinal and seasonal distribution of butterflies (Lepidoptera, Papilionoidea) in Cerro Bufa El Diente, Tamaulipas, Mexico.

Butterflies are one of the most recognized and useful groups for the monitoring and establishment of important conservation areas and management policies. In the present study, we estimate the richness and diversity, as well as the association value of submontane scrub, oak forest, and cloud forest species at Cerro Bufa El Diente, within the Sierra de San Carlos priority land region, located in the Central-western region of Tamaulipas, Mexico. Three sampling sites were established based on criteria of vegetation distribution per altitudinal floor. One site for each altitudinal floor and vegetation type. Sampling was carried out in permanent transects on a monthly basis at each site, using an aerial entomological net and ten Van Someren-Rydon traps, during four sampling periods: early dry season, late dry season, early wet season and late wet season. In total, 7,611 specimens belonging to six families, 20 subfamilies, 32 tribes, 148 genera and 243 species of the study area were collected. Nymphalidae was the most abundant family with 3,454 specimens, representing 45.38% of total abundance in the study area. Lower abundance was recorded in Hesperiidae (19.17%), Pieridae (16.41%), Lycaenidae (10.17%), Papilionidae (5.12%), and finally Riodinidae (3.74%). The highest species richness was presented in the family Hesperiidae with 34.57% of the total obtained species followed by Nymphalidae (30.45%), Lycaenidae (15.23%), Pieridae (9.88%), Papilionidae (5.76%), and Riodinidae (4.12%). Twenty-seven species were categorized as abundant, these species, Anaea aidea (Guérin-Méneville, 1844), Libytheana carinenta larvata (Strecker, 1878), Pyrgus oileus (Linnaeus, 1767), Mestra amymone (Ménétriés, 1857) and Phoebis agarithe agarithe (Boisduval, 1836) presented the highest number of specimens. Sixty-five species were considered common, constituting 41.73% of the total number of butterflies, 63 frequent (9.76% of the total abundance), 55 limited (2.54%) and 33 rare (0.43%). The greatest number of specimens and species, as well as alpha diversity, were presented on the lowest altitudinal floor, made up of submontane scrub, and decreased significantly with increasing altitude. According to the cluster analysis, low and intermediate altitude sites constitute an area of distribution of species that prefer tropical conditions, while the third-floor site forms an independent group of high mountain species. The greatest abundance and richness of species, as well as alpha diversity, was obtained during the last wet season, decreasing significantly towards the early dry season. Moreover, through the use of the association value, 19 species were designated as indicators, three for the last altitudinal floor, three for the intermediate and 13 for the first. The present work represents the first report of the altitudinal variation in richness, abundance and diversity of butterflies in the northeast of Mexico. These results highlight the importance of the conservation of this heterogeneous habitat and establish reference data for the diurnal Lepidoptera fauna of the region.

DETECTION OF ALGAL BLOOM IN THE COASTAL WATERS OF BORACAY, PHILIPPINES USING NORMALIZED DIFFERENCE VEGETATION INDEX (NDVI) AND FLOATING ALGAE INDEX (FAI)

Abstract. Boracay is a top tourist island in the Philippines known for its 4-km beach with powdery white sand. Recently, abundance of green algae, an indicator of high nutrient discharge, along the coastal waters of the island had led to concerns on its water quality and prompted its closure to allow ample time for rehabilitation. This study examined the algal bloom along the coastal waters of Boracay through the determination of Normalized Difference Vegetation Index (NDVI) and Floating Algae Index (FAI). ENVI and SNAP software were used to process the satellite images of Boracay obtained from its pre-closure to its reopening. Necessary corrections such as scaling to Top of Atmospheric radiance were applied. NDVI was calculated using orthotile images to determine vegetation and FAI was calculated using Sentinel-2A images. Secondary data showed that the coliform level decreased from 1 million to 18.1 MPN per 100 mL after the rehabilitation of Boracay. Lower NDVI and FAI index values were observed during the reopening of the island. The NDVI value decreased while the FAI value slightly increased on the 1st month of closure which was late dry season. Both NDVI and FAI values increased to their maximum during early wet season and eventually decreased during the reopening of Boracay. Results showed that the abundance of algae had lowered after the rehabilitation of Boracay. However, fluctuating NDVI and FAI values showed the possible seasonal effects on the algal bloom in the island. Further studies considering the other factors on algal blooms may be done.

Geo-Spatial Heat Index and Comfort Analysis of Port Harcourt City: An Approach to Environmental Health Care Delivery

This research examined the geo-spatial heat index and comfort analysis of Port Harcourt city as an approach to environmental health care delivery. Temperature data were generated from different land use types across days of the week in both wet (April to September) and dry (October to March) seasons. Heat index was derived when air temperature and dew point temperature of the locations were corresponded in the heat index chart or data logger calculator. Findings indicate that the city had experienced danger levels of discomfort above 41oC in the late dry season of January, February and March showing that heat cramps and heat exhaustion as well as heat stroke were probably to occur with continued activity of a person. On the other hand, early dry season of October, November and December had the best human comfort period of &lt; 26.7oC temperature except Thursday and Friday with caution level of 27 to 32°C in the city of Port Harcourt; though fatigue was possible as prolonged exposure could result to heat cramps. High residential/commercial and administrative/industrial land uses had the highest human discomfort indicating that those living in these land use types would suffer extreme hazard of heat stroke. However, recreation and rural sites were the most comfortable land use types. Young children and old people are generally in more danger to the heat effects as the city has exceeded the 27oC thermal comfort threshold. It is therefore recommended that city planners and development practitioners should implement urban green policy of tree planting with special attention to residential/commercial and administrative/industrial areas without further delay in order to cushion the deadly menace of urban heat in Port Harcourt city and its environs.

Participatory epidemiological survey of foot-and-mouth disease among some cattle diseases in some pastoral communities of Niger, north central, Nigeria

Foot-and-mouth disease (FMD) is known to cause significant financial losses, making it a threat to the livelihood and food security. Disease surveillance in pastoral areas are often difficult because human populations are relatively small and highly mobile, and requires considerable flexibility and commitment. Participatory epidemiological approach was used to assess relative burden, seasonality and perceived risk factors of FMD among other important cattle diseases in cattle population of pastoral communities of North-central, Nigeria. Nine pastoral communities and three key informants from each community were purposively selected for the survey between January and December 2014. Participatory rural appraisal tools were used for participatory exercises. Kendall’s Coefficient of Concordance W statistics was used for statistical analyses. Mean proportional piles (relative burden) of FMD (Boru,Chabo) was 17.2%, and pastoralists’agreement on the piles was strong (W=0.6855) and statistically significant (P<0.001). Key informants’ perceived risk factors for FMD were: keeping healthy cattle with sick ones (17.2%), high cattle density (16.8%), grazing cattle in areas of FMD outbreaks (12.4%), long distance trekking (10.3%), giving out cattle as gift or payment for dowry (8.2%), and cattle rustling (4.9%). The key informants agreement on the risk factors was strong (W=0.8372) and statistically significant (p<0.01). FMD occurred in all seasons, but more in late rainy season (Damina) and less in late dry season (Rani). Agreement on FMD seasonal occurrence was strong (W=0.8719) and statistically significant (P<0.01). This survey revealed the relative burden and seasonal impacts of FMD in pastoral herds in North-central Nigeria. FMD surveillance, control and prevention programmes that take these factors into consideration will be beneficial to the livestock industry. The combined use of Participatory epidemiological techniques and clinical record of cases is essential for cost effective disease surveillance, reporting and control strategies in Nigeria.Keywords: Burden, FMD, Fulani pastoralists, Participatory Epidemiology, season, Nigeria

Regional seasonality of fire size and fire weather conditions across Australia's northern savanna

Australia’s northern savannas have among the highest fire frequencies in the world. The climate is monsoonal, with a long, dry season of up to 9 months, during which most fires occur. The Australian Government’s Emissions Reduction Fund allows land managers to generate carbon credits by abating the direct emissions of CO2 equivalent gases via prescribed burning that shifts the fire regime from predominantly large, high-intensity late dry season fires to a more benign, early dry season fire regime. However, the Australian savannas are vast and there is significant variation in weather conditions and seasonality, which is likely to result in spatial and temporal variations in the commencement and length of late dry season conditions. Here, we assess the temporal and spatial consistency of the commencement of late dry season conditions, defined as those months that maximise fire size and where the most extreme fire weather conditions exist. The results demonstrate that significant yearly, seasonal and spatial variations in fire size and fire weather conditions exist, both within and between bioregions. The effective start of late dry season conditions, as defined by those months that maximise fire size and where the most extreme fire weather variables exist, is variable across the savannas.

TROPOMI reveals dry-season increase of solar-induced chlorophyll fluorescence in the Amazon forest

Photosynthesis of the Amazon rainforest plays an important role in the regional and global carbon cycles, but, despite considerable in situ and space-based observations, it has been intensely debated whether there is a dry-season increase in greenness and photosynthesis of the moist tropical Amazonian forests. Solar-induced chlorophyll fluorescence (SIF), which is emitted by chlorophyll, has a strong positive linear relationship with photosynthesis at the canopy scale. Recent advancements have allowed us to observe SIF globally with Earth observation satellites. Here we show that forest SIF did not decrease in the early dry season and increased substantially in the late dry season and early part of wet season, using SIF data from the Tropospheric Monitoring Instrument (TROPOMI), which has unprecedented spatial resolution and near-daily global coverage. Using in situ CO2 eddy flux data, we also show that cloud cover rarely affects photosynthesis at TROPOMI's midday overpass, a time when the forest canopy is most often light-saturated. The observed dry-season increases of forest SIF are not strongly affected by sun-sensor geometry, which was attributed as creating a pseudo dry-season green-up in the surface reflectance data. Our results provide strong evidence that greenness, SIF, and photosynthesis of the tropical Amazonian forest increase during the dry season.

A socio-economic study of Fasciola infections in cattle and sheep at the Etoudi slaughterhouse, Yaoundé, Cameroon.

A cross-sectional socio-economic study of fascioliasis in livestock was carried out at the Livestock Development Cooperation (SODEPA) slaughterhouse in Etoudi, Yaoundé during the periods covering the beginning and late dry season in the northern and eastern regions of Cameroon. A total of 768 cattle and 267 sheep were inspected for the presence of Fasciola species. The overall infection rate in cattle and sheep was 18% (n = 767) and 27% (n = 267), respectively. For the animals that were Fasciola positive, a total of 267.86 kg of liver in cattle was condemned, resulting in a loss of US$1124, while a total of 57 kg of liver was condemned from the sheep population, amounting to a loss of US$114. A total of US$76,097 was determined as losses incurred from condemnation of liver for both cattle and sheep per annum based on the total number slaughtered each year. The findings indicate that fascioliasis is present in cattle and sheep slaughtered in Cameroon and that it causes great economic losses due to condemnation of liver. The local climatic conditions, husbandry systems and the presence of snails (intermediate hosts) are probably the main factors influencing the incidence of the disease and may account for the epidemiological significance found in this study.

Does a bigger mouth make you fatter? Linking intraspecific gape variability to body condition of a tropical predatory fish.

In gape-limited predators, gape size restricts the maximum prey size a predator is capable to ingest. However, studies investigating the energetic consequences of this relationship remain scarce. In this study, we tested the hypothesis that gape-size variability influences individual body condition (a common proxy for fitness) in one of the largest freshwater teleost predators, the barramundi. We found that individual barramundi with larger gapes relative to body size had higher body condition values compared to conspecifics with smaller gapes. Body condition was highest soon after the wet season, a period of high feeding activity on productive inundated floodplains, and body condition decreased as the dry season progressed when fish were restricted to dry season remnant habitats. The increased condition obtained during the wet season apparently offsets weight loss through the dry season, as individuals with large gapes were still in better condition than fish with small gapes in the late-dry season. Elucidation of the links between intraspecific variability in traits and performance is a critical challenge in functional ecology. This study emphasizes that even small intraspecific variability in morphological trait values can potentially affect individual fitness within a species' distribution.

Estuarine ecocline function and essential habitats for fish larvae in tropical South Western Atlantic estuaries

Estuarine gradients rule the dispersal of larval fishes leading to community replenishment and the recruitment of juveniles to adult populations. Here, the variations in density and diversity of fish larvae communities were assessed to understand whether the seasonal variability of environmental forcings in two tropical estuaries express the estuarine function for larvae. Spatial differences ruled larval dispersal. Larval recruitment to the Caeté Estuary occurs in the upper estuary in the late-dry season. Species richness is higher when temperature, salinity and precipitation increase, while changes in diversity is more pronounced in the lower estuary due to salinity variability. Larval recruitment to the Goiana Estuary occurs in the lower estuary, with peaks during wet warmer conditions. Species richness and diversity are also higher seawards. Thus, the seasonal fluctuation of the salinity ecocline had a greater power to predict larvae distribution and diversity by retaining larvae in essential habitats with suitable environmental conditions.