Late Dry Season Research Articles

Assessment of Ambient Air Quality around Ihetutu Minefield, Ishiagu, Nigeria

This study assessed the levels of physicochemical characteristics and heavy metals in ambient air around Ihetutu community in Ishiagu, Nigeria, to evaluate the impact of prolonged Pb-Zn mining and several other related activities on air quality in the area. Particulates, heavy metals, microclimatic and gaseous parameters in ambient air were analyzed for the assessment. Sampling and quality measurements were done during rainy, late rainy, dry and late dry seasons between 2018 and 2019, from study and control areas. Samples were analyzed for particulates and heavy metals in the laboratory while microclimatic and gaseous parameters were measured in-situ using standard field equipment and procedures. Mean and seasonal concentrations of parameters were determined to evaluate the ambient air quality at various locations in the study area. Results showed high mean values of some parameters including; ambient temperature (35.19oC), Relative Humidity (65.78%), SO2 (0.33ppm), NO2 (0.30ppm), PM10 (89.73µg/m3), Cu (0.03mg/L), Zn (0.06mg/L), Fe (0.39mg/L), Mn (2.28mg/L), Ni (0.04mg/L) and Pb (0.05mg/L). Highest Noise level in the study area was 60.40 dB(A). SO2 and NO2 were below detection limits during the dry seasons, but with mean levels above daily average limits of DPR, NESREA, and WHO, due to their high levels during the rainy seasons, except at Amaonye Square. CO mean levels were above FMEnv daily average limit but within DPR limit. PM10 mean values were within NESREA recommended daily average limit while dry season values were above. Zn and Fe pollution along the stations were in the order of SAS3>SAS4>SAS5, while Pb pollution was SAS3>SAS4=SAS5. Generally, trend of heavy metal pollution was Mn>Fe>Pb>Zn>Cd=Cu=Ni. Highest positive correlation within the heavy metals was between Zn and Fe (r = 1.000). There were also no statistically significant differences in means of the parameters among sampling stations (p>0.05). The results revealed pollution of ambient air in the area by heavy metals and gaseous substances, especially around the mining sites and high traffic areas. Proper monitoring of the operations of mining companies and other artisan activities is recommended, to ensure that ambient air status in the area is excellent and within standard guidelines.

Climatic Records to Aid Urban Planning and Improvement of Thermal Comfort in Buildings: A Case Study on Agege-Lagos, Nigeria

The thermal comfort in a building enables the spread of communicable diseases or initiate skin irritations amongst others. Most models on thermal comfort have proven to be localized in the application, as thermal comfort depends on the climatic condition over a geographical area. Based on the above, there is the need to adopt the local method to understand the thermal comfort indexes in Agege. Thirty-nine years dataset (1980-2018) of temperature, relative humidity, wind speed, and wind direction was obtained from MERRA-NASA database for Agege, Lagos Nigeria. The dataset was divided into early dry season (i.e. September, October, November- SON), late dry season (i.e. December, January February-DJF), early wet season (i.e. March, April, May – MAM) and late wet season (i.e. June, July, August-JJA). It was observed that the effect of climate change was significant. Hence, it is recommended that the inhabitants of the area should go green by planting trees and shrubs. Also, there is a need to modify the urban plan to decongest the area.

Seasonal and Nutrient Supplement Responses in Rumen Microbiota Structure and Metabolites of Tropical Rangeland Cattle.

This study aimed to characterize the rumen microbiota structure of cattle grazing in tropical rangelands throughout seasons and their responses in rumen ecology and productivity to a N-based supplement during the dry season. Twenty pregnant heifers grazing during the dry season of northern Australia were allocated to either N-supplemented or un-supplemented diets and monitored through the seasons. Rumen fluid, blood, and feces were analyzed before supplementation (mid-dry season), after two months supplementation (late-dry season), and post supplementation (wet season). Supplementation increased average daily weight gain (ADWG), rumen NH3–N, branched fatty acids, butyrate and acetic:propionic ratio, and decreased plasma δ15N. The supplement promoted bacterial populations involved in hemicellulose and pectin degradation and ammonia assimilation: Bacteroidales BS11, Cyanobacteria, and Prevotella spp. During the dry season, fibrolytic populations were promoted: the bacteria Fibrobacter, Cyanobacteria and Kiritimatiellaeota groups; the fungi Cyllamyces; and the protozoa Ostracodinium. The wet season increased the abundances of rumen protozoa and fungi populations, with increases of bacterial families Lachnospiraceae, Ruminococcaceae, and Muribaculaceae; the protozoa Entodinium and Eudiplodinium; the fungi Pecoramyces; and the archaea Methanosphera. In conclusion, the rumen microbiota of cattle grazing in a tropical grassland is distinctive from published studies that mainly describe ruminants consuming better quality diets.

Broad-scale opportunistic movements in the tropical waterbird Anseranas semipalmata: implications for human-wildlife conflicts

ABSTRACT Waterbirds commonly undertake extensive movements in search of resources. While much is known about waterbird movements within temperate regions where resource distribution is seasonally predictable, less is understood about waterbird movements in tropical and subtropical environments where the temporal distribution of resource is less predictable. This knowledge is critical to understanding a species’ response to environmental and anthropogenic changes to natural habitats. Here, we investigated the movement behaviour of a tropical waterbird of northern Australia, the Magpie Goose (Anseranas semipalmata), seasonally utilising a recently developed mixed natural-anthropogenic landscape. Using satellite telemetry, we assessed the daily movements and space use of 18 individuals (4673 goose-days) to determine whether these individuals spent the year locally, migrated seasonally from further areas, or were transitory individuals from across northern Australia. Geese released from peri-urban and rural areas in the late dry season dispersed to both local (≤ 50 km) and distant (≤ 566 km) floodplain systems over the wet season. Tracked individuals returned to sites within the same floodplain systems in the wet season and within the same anthropogenic areas in the late dry season over consecutive years. Our results suggest that anthropogenic environments may provide predictable resources for Magpie Geese during a seasonal bottleneck of natural resources. We highlight the need to learn more about waterbird movement behaviour within tropical human-dominated landscapes to evaluate the likelihood that predictable resources could exacerbate human–wildlife conflicts, and the possible long-term effects on species population dynamics, behaviour and distribution.

Fenología de la especie amenazada Leptocereus scopulophilus (Cactaceae) en un bosque semideciduo de Cuba occidental

Antecedentes y Objetivos: Los estudios fenológicos han mostrado su utilidad para entender la dinámica de los ecosistemas y pueden ser útiles para la conservación de especies vegetales. En cactáceas son escasos los estudios que evalúan la fenología reproductiva y vegetativa, en particular sobre especies de bosques semideciduos. El presente estudio aborda diferentes aspectos de la fenología de Leptocereus scopulophilus, una cactácea amenazada y endémica presente en un bosque semideciduo de Cuba occidental. Este estudio tiene como objetivos principales caracterizar la fenología de L. scopulophilus, comparar su comportamiento interanual con diferentes regímenes de precipitación y evaluar las relaciones entre las fenofases y las variables ambientales. Métodos: Se seleccionaron 50 individuos adultos y se registraron, mensualmente durante tres años, el número de botones, flores, frutos, así como el crecimiento vegetativo y los retrocesos de una rama seleccionada al azar. Se evaluaron mensualmente el porcentaje de iluminación, la temperatura, la humedad relativa y las precipitaciones. Los patrones anuales e interanuales de cada fenofase fueron comparados mediante estadística circular. La relación existente entre variables ambientales y las fenofases se evaluó con una correlación de Spearman. Resultados clave: Los patrones de floración y fructificación resultaron unimodales con máximos desfasados en un mes. La floración coincidió con el final de la época seca y la fructificación ocurrió al inicio de la época lluviosa. El crecimiento vegetativo fue generalmente de forma aleatoria y simultáneo a la reproducción, mientras el retroceso de las ramas sucedió durante la época lluviosa. La variable más correlacionada con las fenofases fue la iluminación. Conclusiones: La apertura del dosel del bosque semideciduo donde habita L. scopulophilus favorece la reproducción y el crecimiento de sus ramas. Este evento estuvo modulado por la duración e intensidad de las lluvias de la temporada previa.

Restoring fish habitat values on a tropical agricultural floodplain: Learning from two decades of aquatic invasive plant maintenance efforts

Coastal managers are increasingly challenged with implementing expensive restoration and on-going maintenance programs to reinstate the services and values of floodplains as important fish nursery areas, but access to long-term data to assist with supporting success is lacking. An environmental levy (funded by farmers, Burdekin Shire Council, a local Natural Resource Management group, and Lower Burdekin Water Board) was enacted in 2003 to fund (approximately $20,000/yr AUD) an ongoing aquatic weed removal program (consisting of an aquatic plant weed harvester that removes floating vegetation to a nearby truck for composting in conjunction with boat weed spraying) designed to maintain the delivery of irrigation water as well as promoting productive fish habitat. We repeated a fish and water quality survey first performed in 2001/2002 (September 2017, May 2018) at 10 lagoons (three clear and seven turbid) on the Burdekin floodplain (north Queensland, Australia) to examine whether these maintenance efforts continue delivering the initial values set nearly 20 years ago. A total of 2267 fish from 24 species were caught, May 2018 (post-wet season) survey yielded more fish (24 species) than the September 2017 (late dry season) survey (19 species) which is close to the results of the 2001/02 survey (post-wet season, 17 species; late dry season, 16 species). A Hydrolab (September 2017) revealed that turbid and clear water lagoons had a similar rhythmic diel temperature cycle that posed no thermal risks to fish. Dissolved oxygen had distinct diel periodicity, with clear lagoons having the widest range, reaching established critical minimum thresholds for some floodplain fish, while turbid lagoons were generally less variable (presumably due to less oxygen demand from biological activity). While as long as sugarcane production occurs, excessive nutrients will necessitate continuance of the aquatic weed program; therefore, the funding model in place must remain. This study advocates the need for long-term maintenance programs facilitated by long-term partnerships, and serves as an exemplar model for managers looking to restore coastal floodplains but are challenged with persistent aquatic weed management issues, not only in Australia but also on floodplains elsewhere.

Investigation of native chicken mortality/loss in the free-range system: Causes, control measures and impact to farmers at the household level, Moyamba District, Southern Sierra Leone

The increase in mortality/loss of native chickens in the rural areas of Sierra Leone is posing a serious threat to the traditional chicken industry. Poultry farmers loss many chickens annually which hugely undercut their livelihood and social status. This research was therefore conducted to investigate the main causes of native chicken mortality/loss, control strategies and how it influences the livelihood of farmers in Moyamba district, Sierra Leone. The data was obtained through field survey, personal discussion and observation from randomly selected 300 participants in 6 villages. The findings revealed that 84.3% of the interviewed farmers were female while the overall illiteracy rate of the participants was 72.3%. The average number of the different livestock kept by the farmers were: 7.8 (chicken), 0.3 (duck), 0.6 (sheep), 0.2 (pig) and 3.4 (goat). 45.5% of the mortality/loss recorded from 2017-2018 was said to be caused by predators while 54.5% was caused by diseases/parasites and other factors (2017-2018). 33.0 and 32.0% of the mortality/loss occurred during the late dry and early rainy seasons while 20.0 and 15.0% occurred in the early dry and late rainy seasons respectively. Settlements along the grassland and forested areas reported a high incidence of predators while the river-line areas reported high cases of diseases/parasites. The main predators identified were hawk, red fox and eagle while Newcastle disease and lice were the most serious disease and parasites named respectively. The animal healthcare services are inadequate and therefore, traditional methods of controlling diseases/parasites and predators are widely adopted. The impact of mortality/loss to farmers at household level include low protein intake, loss of income, weak cultural/religious practices, loss of flock, food insecurity, increase in poverty and lack of job. Therefore, there is a need for effective and continuous implementation of disease/parasites control programs in the study areas by strengthening the veterinary and the extension services for better productivity and improved management practices.

Induction of long-lived potential aestivation states in laboratory An. gambiae mosquitoes

BackgroundHow anopheline mosquitoes persist through the long dry season in Africa remains a gap in our understanding of these malaria vectors. To span this period in locations such as the Sahelian zone of Mali, mosquitoes must either migrate to areas of permanent water, recolonize areas as they again become favorable, or survive in harsh conditions including high temperatures, low humidity, and an absence of surface water (required for breeding). Adult mosquitoes surviving through this season must dramatically extend their typical lifespan (averaging 2–3 weeks) to 7 months. Previous work has found evidence that the malaria mosquito An. coluzzii, survives over 200 days in the wild between rainy seasons in a presumed state of aestivation (hibernation), but this state has so far not been replicated in laboratory conditions. The inability to recapitulate aestivation in the lab hinders addressing key questions such as how this state is induced, how it affects malaria vector competence, and its impact on disease transmission.MethodsIn effort to induce aestivation, we held laboratory mosquitoes in climate-controlled incubators with a range of conditions that adjusted humidity (40–85% RH), temperature (18–27 °C), and light conditions (8–12 h of light) and evaluated their survivorship. These conditions were chosen to mimic the late rainy and dry seasons as well as relevant extremes these mosquitoes may experience during aestivation.ResultsWe found that by priming mosquitoes in conditions simulating the late wet season in Mali, and maintaining mosquitoes in reduced light/temperature, mean mosquito survival increased from 18.34 ± 0.65 to 48.02 ± 2.87 days, median survival increased from 19 (95% CI 17–21) to 50 days (95% CI 40–58), and the maximum longevity increased from 38 to 109 days (P-adj < 0.001). While this increase falls short of the 200 + day survival seen in field mosquitoes, this extension is substantially higher than previously found through environmental or dietary modulation and is hard to reconcile with states other than aestivation. This finding will provide a platform for future characterization of this state, and allow for comparison to field collected samples.

Relative Contribution of Precipitation and Air Temperature on Dry Season Drying in India, 1951–2018

AbstractSoil moisture plays an essential role in food production and land‐atmosphere feedback. However, the relative contribution of precipitation and air temperature on dry season (October–December) soil moisture has not been systematically examined in India. Using observations and simulations from the Variable Infiltration Capacity model, a significant (4%, p value = 0.04) decline in soil moisture (dry season drying hereafter) was found in a large part of India during the 1951–2018. The decline in the summer monsoon precipitation in India during 1951–2018 is mainly due to a decrease in rainfall during the late monsoon season (August–September). A substantial decline (−18.6%, p value = 0.009) in the late monsoon and (−26%, p value = 0.19) dry season precipitation was observed. A significant warming (0.75°C, p value = 0.002) has occurred during the dry season between 1951 and 2018. The relative contribution of decline in precipitation in the late monsoon (30%) and dry season (34%) is considerably higher than the dry season warming (15%). The previously unexplored role of climate warming on the dry season drying was analyzed using Maximum Covariance Analysis between precipitation and sea surface temperature, which suggests both large‐scale and localized influences. Climate warming over the Indian and Atlantic Oceans is associated with declining precipitation during the late monsoon and dry seasons over central India. Also, climate warming over land exacerbates the dry season drying by depleting soil moisture. The dry season drying over a large part of India contributed by climate warming has substantial implications for irrigation water management and groundwater abstraction.

What grass characteristics drive large herbivore feeding patch selection? A case study from a South African grassland protected area

The coexistence of a large herbivore community depends on the degree of overlap in the resource used by the different species composing it. We investigated the role of grass greenness, height, biomass and feeding patch status on feeding patch selection by ruminant black and blue wildebeest (Connochaetes gnou, Connochaetes taurinus), red hartebeest (Alcelaphus buselaphus) and non-ruminant plains zebra (Equus quagga) in a protected grassland in South Africa. Selection by ruminants was associated with grass greenness and grass height, <10 cm for black and blue wildebeest, and >11 cm for red hartebeest. The non-ruminant zebra were more generalist, but selected for wetlands in all seasons, as did red hartebeest and blue wildebeest. Each species modified its behaviour during the late dry season by searching more for biomass or accepting grass that was less green or longer. The presence of burnt patches did not affect patch selection by any study species. Accordingly, large herbivore resource use showed strong seasonal adaptations, wetlands were important for sustaining sympatric species in the study area, and none of the species used the exact same combination of resources.

Bovine trypanosomiasis and vectors in Lom and Djerem Division of East-Cameroon

Bovine trypanosomiasis is a major threat to the livestock sector of Cameroon. The main objective of this study was to determine the prevalence of bovine trypanosomes and vectors in the SODEPA Ranch of Ndokayo. A cross sectional parasitological survey was carried out in the late dry season, where blood was collected through the jugular vein of 390 cattle. The trypanosome detection in cattle blood was carried out using the buffy coat technique (BCT). An entomological prospection was carried out in the late dry season and early rainy season using two unbaited trap types notably Nzi (n = 4) and Vavoua (n = 4). The overall bovine trypanosomiasis prevalence was 2.82% and species specific prevalence included: Trypanosoma congolense (63.6%), Trypanosoma brucei (18.2%) and mixed species infections (T. congolense + T. brucei and T. brucei + T. vivax) (18.2%). Sixteen (16) species of flies were identified and grouped under six genera: Stomoxys, Ancala, Tabanus, Chrysops, Hematopota and Glossina. The overall trap apparent density (ADT) was 3.92 flies/trap/day, with a higher ADT in early rainy season than in the late dry season. The highest species richness was noticed with the genus Tabanus, while the highest ADT was found in Stomoxyini. The Nzi trap recorded a higher mean ADT for most fly vectors than Vavoua, except for Stomoxyini that rather recorded a higher ADT with the Vavoua trap. The present findings will instruct fly control authorities of Cameroon to better manage.

Gas composition and its daily changes within burrows and nests of an Afroalpine fossorial rodent, the giant root-rat Tachyoryctes macrocephalus

Fossorial mammals are supposed to face hypoxic and hypercapnic conditions, but such conditions have been rarely encountered in their natural burrow systems. Gas composition in burrows after heavy rains, deeper burrows and especially nest chambers, where animals usually spend most of the day, could be even more challenging than in shallow burrows. Such situations, however, have been rarely surveyed in the wild. In our study, we determined concentrations of O2, CO2 and CH4 in active burrows and nests of the giant root-rat Tachyoryctes macrocephalus, a large fossorial rodent endemic to the Afroalpine zone of the Bale Mountains in Ethiopia. We were able to determine the precise location of nests by tracking individuals equipped with radio-collars. To the best of our knowledge, this is the first study that analyses air samples taken directly from the nests of actually occupied burrow systems in any free-living fossorial mammal. We found no evidence for environmental hypoxia in the examined burrows and nests (range 19.7–21.6% O2). Concentrations of CO2 in the burrows increased after the burrows were plugged in the evening, but did not reach physiologically problematic levels. The highest CO2 concentrations in burrows were detected in the evening during a wet period (up to 0.44%). In root-rat nest chambers, the highest (but still harmless) CO2 concentrations (up to 1.31%) were detected in the morning (measured in the late dry season only) together with an elevated concentration (up to 13.5ppm) of CH4. Regular surface activity of giant root-rats, combined with the relatively large dimensions of their nest chambers and tunnels, and the absence of heavy soils, may contribute to harmless atmospheres within their burrow systems.

Spatial and temporal variation of fish community biomass and energy flow throughout a tropical river network

Abstract Accurately accounting for flows of energy through food webs is challenging because of the spatial and temporal variability associated with energy production and consumption. Wet–dry tropical rivers have a highly seasonal discharge regime where wet season flows allow access to energy sources (inundated wetlands) that are not available during the dry season when aquatic consumers are confined to disconnected waterholes. We combined measures of fish community biomass with previously published feeding guild specific stable isotope analyses to explore how opposing wet‐ and dry‐season habitat templates influence spatial and temporal trends in the sources of energy supporting fish biomass throughout a river network in the wet–dry tropics of northern Australia. Accounting for the relative contribution of each feeding guild to fish community biomass was a critical component of our analyses, as a single feeding guild (invertivore/piscivore) influenced spatial and temporal patterns in the sources of energy supporting overall fish biomass. During the early dry season, the reliance of fish communities on autochthonous sources of energy (periphyton) decreased from the upper to lower reaches of the river network, which correlates with increasing floodplain area and wet season inundation times. These patterns disappeared by the late dry season as fish in both upper and lower reaches became increasingly reliant on autochthonous sources produced within waterholes over the course of the dry season, indicating that the large wet‐season gains in fish biomass are maintained through the dry season by energy produced within waterhole refuges. Collectively these results indicate that a combination of autochthonous and allochthonous sources of energy work in unison to support fish community biomass throughout the Mitchell River catchment and that access to these sources of energy is dictated by seasonal patterns in discharge interacting with spatial variability in river geomorphology (channel geometry and floodplain area). Many rivers are experiencing decreased flows due to water resource development and more frequent and severe droughts. Thus, we suggest our study provides insight into how changes in discharge regime could influence food web energetics throughout river networks.

Prescribed burning benefits threatened mammals in northern Australia

Despite substantial investment in prescribed burning for biodiversity conservation there has been surprisingly little demonstration of its efficacy in achieving intended conservation aims for fauna. In the case of northern Australia’s threatened mammal fauna, most studies have reported negative responses to fire. We used satellite-derived fire scar imagery and small mammal survey data to compare fire regimes and threatened mammal abundance before and after implementation of broad-scale prescribed burning in north-western Australia. Specifically, we tested: (1) whether prescribed burning was effective in changing fire regimes; (2) whether all mammal species and functional groups responded to prescribed burning; and (3) what regional fire and environmental variables explained changes in mammal status. Low-intensity, patchy prescribed burning in the early dry season reduced the extent of high intensity late dry season wildfires. In sandstone habitats the abundance of all mammals, and the large marsupials and specialist rodent functional groups, increased concurrently with early dry season prescribed burning. All mammals and the small dasyurid functional group in woodland habitats also increased during this period. Early dry season prescribed burning extent was the strongest explanatory variable for mammal increases. Early dry season burning was also the strongest explanatory variable for woodland mammal abundance, but these mammals also had a positive association with extent of large patches of old growth vegetation (> 4 years since fire). Generalist rodents did not respond to prescribed burning and two other species declined following prescribed burning in one habitat. Generalist rodents and the two declining species had a negative association with extent of late dry season fire and a positive association with old growth vegetation (interacting with patch size). These results suggest an increased application of patchy early dry season prescribed burning of up to ca. 30% of the area will benefit positive fire responder species of threatened mammals including large specialist rock/arboreal rodents and most marsupial species. For mammals such as generalist terrestrial rodents with predominantly negative associations with fire, managers should seek to increase the size and extent of old growth vegetation.

Rio Doce Acoustic Surveys of Fish Biomass and Aquatic Habitat

ABSTRACTFollowing the failure of the Fundão mine tailings dam in Brazil, approximately 32 million cubic meters of Fe ore tailings were released into the downstream riverine system. The postevent monitoring surveys implemented the use of noninvasive acoustic methods to improve the understanding of the fish biomass distribution patterns and aquatic habitat condition of the impacted reaches of the Rio Gualaxo do Norte, Rio do Carmo, and Rio Doce. The primary focus of the program was to collect hydroacoustic measurements of fish biomass, which was accompanied by sonar imaging of aquatic habitats using high‐resolution side scan and downward imaging sonar at each site visited. The biannual surveys began in April 2017 and were fundamentally a multiple control–impact design because before data (prior to the dam failure event) were not available. Up to 22 sites were visited for each survey, including reservoir and river sites. Results indicate similar levels of instream habitat between control and impact river and reservoir sites. Average volumetric biomass was not significantly different between impact sites and their corresponding controls in the August 2018 survey (latest to date). Preliminary temporal analysis of the biomass data set collected indicates that either stable or increasing levels of biomass are detected at tailings impacted sites within the Rio Doce. Integr Environ Assess Manag 2020;16:615–621. © 2020 Hydrobiology QLD Pty Ltd. Integrated Environmental Assessment and Management published by Wiley Periodicals LLC on behalf of Society of Environmental Toxicology & Chemistry (SETAC)

Drivers of zooplankton dynamics in a small tropical lowland river

There is limited information available on the ecology of planktonic invertebrate assemblages of small tropical lowland rivers, despite zooplankton being a vital resource for larval fish. Herein we describe the spatial patterns and temporal dynamics of invertebrate zooplankton at 8 locations over a 25-month period in the lowland section of a short coastal river in the Australian Wet Tropics. Zooplankton were more abundant in slack than flowing waters and assemblages were dominated by Copepoda, but contained many less numerous taxa, including freshwater invertebrates at the more upstream sites. Taxonomic richness, total density and the densities of the most abundant taxa were greatest in the most downstream sites. Seasonal patterns in the density of zooplankton did not differ between the 2 years. Distance-based linear modelling of assemblages identified distance downstream and associated variables, such as salinity, as the most important environmental effects on zooplankton. The zooplankton assemblage in the lower Mulgrave River is strongly influenced by the incised nature of the river, perennial flows, the presence of slack waters, wet season floods and estuarine incursion. Zooplankton dynamics differ from the typical pattern of tropical floodplain systems in that their maximum proliferation occurs during the benign but productive late dry season.

Bee diversity in secondary forests and coffee plantations in a transition between foothills and highlands in the Guatemalan Pacific Coast.

BackgroundAlthough conservation of pristine habitats is recognized in many countries as crucial for maintaining pollinator diversity, the contribution of secondary forest conservation is poorly recognized in the Latin American context, such as in Guatemala. San Lucas Tolimán (SLT) is a high-quality coffee production region from the Atitlan Province, which has the second highest deciduous forest cover in Guatemala and pristine forest is prioritized for conservation. In contrast, secondary forest protection is undetermined, since these forests are normally removed or strongly affected by coffee farming practices. This situation may affect the diversity of native pollinators, mainly bees, which usually rely on the secondary forest for food resources.MethodsWe conducted a study to investigate the importance of secondary forests around the SLT coffee plantations (Coffea arabica L.) for pollinators. We compared bee diversity (richness, abundance and composition) in secondary forests of different age and coffee plantations with diverse farming techniques. Being the first study of pollinators in Guatemalan coffee plantations, we also recorded data for an entire year (2013–2014) in order to describe bee seasonality.ResultsWe found significant differences in bee diversity between the coffee plantations and secondary forests, particularly early secondary forests showed higher bee abundances but diversity indices were similar between different vegetation type plots. In the early dry season, secondary forests showed the greatest native bee diversity. During the late dry season, when the coffee was flowering, honey bees were dominant in the same plots. This study provides important management insights to support the conservation of pollinators, since our results offer guidelines to improve coffee production by increasing native pollinator diversity.

Fire regime in the Brazilian Savanna: Recent changes, policy and management

In 2019 Brazil recorded the highest wildland fire occurrence South America has seen for the last 15 years. Added to the Amazon, the Brazilian savanna (Cerrado) faces changes in fire regimes. Climatic changes and the recent weakening of environmental law enforcement are factors, but historic and large-scale trends and drivers of fire regimes must be analyzed. We discuss ecological and policy drivers of recent changes in fire regimes in the Cerrado, in order to highlight management strategies. The Cerrado has evolved with natural fires and anthropogenic fires are also common for millennia. In the past 50 years, wildfires tend to be concentrated in the late dry season and to occur every two / three years, causing serious damage in fire-sensitive vegetation. Apart from climatic variations, the drivers of wildfires are deforestation and fire suppression policies. Nearly half of the original vegetation of the Cerrado biome has disappeared largely due to agribusiness expansion. Fire is associated with deforestation in two ways: vegetation conversion to monocultures, and lack of fire management in the remaining native vegetation. Indeed, the attempts to exclude fires from this fire-prone ecosystem disrupted traditional fire management. Fire suppression policies lead to increased wildfire risks due to fuel load and the multiplication of sources of ignition (conflicts, roads). The recent advances in Integrated Fire Management in protected areas in the Cerrado are evident. However, the recent budget cuts by the Brazilian government in environmental management and research undermine the chances of decreasing occurrences of wildfires in this biodiversity hotspot.

Effect of different levels of supplementation after weaning on beef heifer development

The purpose of the study was to identify a cost-effective supplementation regimen to rear replacement heifers on transitional Cymbopogon-Themeda veld. A total of 120 Drakensberger heifers aged 6 - 7 months were randomly allocated to three supplementary treatment groups from 2011 - 2014. A three-phase supplementation programme was used while the production year was divided into three periods, namely summer (wet season) (approximately mid-December to March), winter (early dry season) (April to July), and late winter (late dry season) (August to approximately mid-December). The late winter treatments consisted of three levels of supplemental crude protein (CP), a percentage of protein derived from non-protein nitrogen (NPN) and metabolizable energy (ME), namely T1: 306 g CP/kg (47.4% NPN) + ME 7.4 MJ/kg; T2: 329 g CP/kg (70.72% NPN) + ME 6.89 MJ/kg; and T3: 475 g CP/kg (95.86% NPN) + ME 2.4 MJ/kg. In summer, T1 was supplemented with 164 g CP/kg (7% NPN) + ME 9 MJ/kg + 13 g P/kg; T2 with Voermol Superfos with 150 g CP/kg (13.6% NPN), ME 0 MJ/kg, and 50 g P/kg; T3: 0 g CP/kg, ME 0 MJ/kg, and 60 g P/kg. The traits were nutrient intake, supplement cost, mean bodyweight, weight gains/losses and mean BCS. The study concluded that feeding replacement heifers to traditional bodyweight increased development costs without improving production sufficiently. Veld that is in good condition together with a mineral (60 g P/kg) supplement in the wet season and a protein and mineral supplement (96% NPN) in the dry season gives the highest economic return.&#x0D; Keywords: beef heifers, post wean, supplementation

Listening and watching: Do camera traps or acoustic sensors more efficiently detect wild chimpanzees in an open habitat?

Abstract With one million animal species at risk of extinction, there is an urgent need to regularly monitor threatened species. However, in practice this is challenging, especially with wide‐ranging, elusive and cryptic species or those that occur at low density. Here we compare two non‐invasive methods, passive acoustic monitoring (n = 12) and camera trapping (n = 53), to detect chimpanzees Pan troglodytes in a savanna‐woodland mosaic habitat at the Issa Valley, Tanzania. With occupancy modelling we evaluate the efficacy of each method, using the estimated number of sampling days needed to establish chimpanzee absence with 95% probability, as our measure of efficacy. Passive acoustic monitoring was more efficient than camera trapping in detecting wild chimpanzees. Detectability varied over seasons, likely due to social and ecological factors that influence party size and vocalization rate. The acoustic method can infer chimpanzee absence with less than 10 days of recordings in the field during the late dry season, the period of highest detectability, which was five times faster than the visual method. Synthesis and applications. Despite some technical limitations, we demonstrate that passive acoustic monitoring is a powerful tool for species monitoring. Its applicability in evaluating presence/absence, especially but not exclusively for loud call species, such as cetaceans, elephants, gibbons or chimpanzees provides a more efficient way of monitoring populations and inform conservation plans to mediate species‐loss.