Late Dry Season Research Articles

Reproductive phenology of timber tree species in the Yungas Piedmont Forest of Argentina

The tree reproductive phenology in the seasonal neotropical forest is driven by many abiotic and biotic factors and provides information to understand the biological processes of ecosystems. The Yungas Piedmont Forest in Argentina is one of the areas with the greatest biodiversity and timber resources in the country. However, limited knowledge of the reproductive phenology of these species has resulted in inadequate management plans and protocols. In this study, we observed the reproductive phenology of eight timber tree species in the Yungas Piedmont Forest over a two-year period and evaluated the relationship between local climatic conditions (temperature, precipitation, and photoperiod) and reproductive phenology. In the Yungas Piedmont forest, the reproductive phenology of timber tree species presented intermediate intensity, and short duration. The reproductive phenology of each species was seasonal and mainly modulated by photoperiod. Concerning the timing of each phenophase, we found interspecific variation in reproductive phenological strategies. Flowering occurred mainly during the late dry season up to early wet season and fruiting had two annual intensity peaks, one per season. This study provides valuable information on the phenological patterns of economically important tree species in the Andean Forest, and it is essential for underpinning conservation and restoration actions in the Yungas forests.

Carbon-dioxide-driven increase in foliage projective cover is not the same as increased woody plant density: lessons from an Australian tropical savanna

Carbon accounting in tropical savannas relies on a good understanding of the effects of atmospheric carbon dioxide (CO2) and land management on foliage projective cover (FPC) and vegetation structure. We used generalised additive modelling to track changes in Autumn Persistent Green (APG, a satellite-image-derived measure of FPC) in six vegetation types on Cape York Peninsula, Australia, over an 18-year period, and examined the influence of fire and grazing land tenure. We then used field monitoring and variography (analysis of spatial autocorrelation) in a smaller study area to determine whether changes in APG reflected vegetation structural change. APG increased through the 18-year study period and was significantly influenced by vegetation type, recent fire history and grazing land tenure. Residual year-on-year increases suggest CO2 fertilisation was the main driver of APG increase. APG was reduced by fires in the previous year, with early dry season fires having greater impact than late dry season fires, particularly in grassland and rainforest. This is consistent with leaves being most fire sensitive early in the year, when they are actively growing, than in the late dry season, when they are dormant. As seedlings and suckers would be particularly fire-sensitive, early fires may therefore be more effective than late fires at preventing woody encroachment. We demonstrated that variography provides a good indication of whether APG increases are caused by increases in FPC alone, or by an increase in tree density. We found support for increased woody plant density in grasslands, and that this increase was most pronounced on grazing lands. Conversely, we found no support for stem density increases in the dominant eucalypt woodland, despite APG increases being highest in this vegetation type. Hence, increases in FPC cannot always be equated to increases in woody biomass, and may occur in their absence. This conclusion has serious implications for global carbon accounting.

Using digital photography to monitor changes in biocrusts and ground cover in a savanna rangeland

Biocrusts form a living soil cover in Australia’s northern savannas, delivering essential ecosystem services. More accessible tools are needed to quantify and monitor ground cover, including biocrusts, as current methodologies are time-consuming, expensive, or specialised. At Victoria River Research Station (Northern Territory, Australia), long-term fire research plots were used to monitor the response of low vegetative ground and soil covers for different burning intervals and seasons. Mobile phone photographs were analysed using machine-learning software and a derived decision tree-based segmentation model (DTSM). The resulting data were compared to visual in-field assessment by trained researchers. Visual assessments and photographs were taken at two time points during the post-fire recovery period, mid-wet and dry seasons, at three burning intervals (2, 4, and 6 years) and for two different burning times, early or late dry season. DTSM-derived grass and litter cover were statistically similar to field observations in the burnt and unburnt plots. Biocrust cover derived from DTSM also matched field observations in fire treatments and unburnt control plots in the dry season, except when obscured by grass or litter. In the wet season, DTSM underestimated biocrust cover in some treatments, and DTSM did not detect biocrust obscured under dense grass cover. Nevertheless, biocrust pigment analysis confirmed a significant presence of biocrusts both on seemingly bare soil and under the grass canopy. We concluded that mobile phone photographs are suitable for monitoring dry-season ground cover. When similar colours of grass and litter cover were combined, the modelled accuracy reached 95–97%. With some refinements, DTSM analysis of photographs could accurately quantify the impact of fire disturbance on biocrusts and grass cover. However, it would be advantageous to improve the model by additional field records to determine how much biocrust occurs under the grass. This study provides land managers with an efficient method of recording ground cover over time to aid land-condition assessments.

Nutritive value and herbage mass of Pueraria phaseoloides (tropical kudzu) in un-utilized open grasslands in north-eastern and central Trinidad and Tobago

Pueraria phaseoloides is an important forage for ruminants in the tropics. However, its nutritive value and availability in areas easily accessed by ruminants and ruminant farmers in Trinidad and Tobago is unknown. This study, therefore, evaluated the effects of harvest date and location on the nutritive value, herbage mass and crude protein yield of P. phaseoloides in un-utilized open grasslands in three locations with high livestock density in Trinidad. Pueraria phaseoloides herbage (whole fraction and leaf) trailing on the upper canopy of open un-utilized grasslands were harvested in the late wet season of 2019 (October - November), early dry (January - February) and early wet (July - August) seasons of 2020 following a stratified random sampling scheme. The crude protein (CP) concentrations of P. phaseoloides leaves (235 g/kg DM) and whole fraction (217 g/kg DM) were highest in Wallerfield during the early wet season. Neutral detergent fibre (NDF), acid detergent fibre (ADF) and lignin were lowest in the early dry season (P < 0.01). Crude protein yield (376–478 kg CP ha−1) and herbage mass (1,742–2,654 kg DM ha−1) were highest during the late wet and early dry season, respectively. In vitro organic matter digestibility (IVOMD) of P. phaseoloides leaf (548–598 g/kg) and whole fraction (549 –580 g/kg) were highest in the late wet season. It was, therefore concluded that open un-utilized grasslands in Trinidad and Tobago produced significant amount of P. phaseoloides herbage year-round to support ruminant livestock production. However, the nutritive value, herbage mass and CP yield of P. phaseoloides herbage were highest during the late wet and early dry seasons.

Ovarian cycle, reproductive performance and breeding seasonality of Amazonian yellow-footed tortoises (Chelonoidis denticulatus) in the wild

Studies of the reproductive functional morphology of chelonians are important to understand the reproductive physiology, anatomy, and endocrinology of these species. However, data on the reproduction of this group have been difficult to obtain because of their cryptic habits and as a result the consequent inefficiency of conventional field methods in detecting individuals in the wild. In this study, we obtained reproductive organs from 347 adult female yellow-footed tortoises (Chelonoidis denticulatus), one of the most hunted and traded land vertebrates in South America, donated by local sellers in a wild meat market in the Peruvian Amazon. We described the species’ reproductive cycle and the influence of climatic factors on reproductive performance. Of the sampled females, 116 (33.4%) were gravid and 231 (66.6%) were non-gravid, including 215 vitellogenic (62.0%) and 16 non-vitellogenic (4.6%). The mean number of ovarian follicles per female declined from 28.5 (<10 mm diameter), to 7.1 follicles (20–40 mm) to 3.2 follicles> 40 mm. Gravid females had in average 3.7 shelled eggs in the oviduct, with a mean egg diameter of 53.7 mm. The estimated annual reproductive potential in gravid females was 5.1 eggs per clutch, ranging from one to 22 eggs. There was a strong positive relationship between the diameter of shelled eggs and the straight carapace length of gravid females. The final phase of the folicular growth, the most demanding energetic process in chelonian reproduction, correlated with annual rainfall peak, while oviposition was estimated to occur in the dry season. The yellow-footed tortoise should be considered an opportunistic seasonal breeder, though capable of reproducing throughout the year. Reproductive yields are linked to climatic events that influence food availability in the environment. To improve the sustainable use of this species, adult females should be harvested primarily during reproductive quiescence, from the end of the laying period in the late dry season to the mid-rainy season when large follicles appear, to avoid taking gravid females. Our results are useful not just to better understand the reproductive biology of terrestrial chelonians but can inform the conservation management of harvested species.

The threatened Gouldian finch preferentially forages in prescribed burnt savannas

Background The granivorous finches of Australia’s tropical savannas heavily rely on a sequence of perennial and annual grass seed production to feed throughout the year. An increase in late dry season wildfires has been suggested to detrimentally effect seed production sequence and has been attributed to poor physiological condition and a reduction in fitness of granivorous finches. Early dry season prescribed burning is an asset protection management strategy often implemented to reduce the incidence of late dry season wildfire, but has also been shown to improve the abundance and nutritional quality of grass seed Aims To assess whether the Gouldian finch (Chloebia gouldiae) preferentially used areas that were subject to early dry season prescribed burning over areas that were not burnt. Methods The creation of a landscape mosaic across the landscape with varying fire histories. Then the assessment of individual finch movement and site utilisation using VHF-radio telemetry transmitters, detected by an array of static receivers deployed across the landscape. Key results Finches significantly preferred to forage in areas burnt in the early season every 2–3 years. Conclusions The study demonstrates that early dry season prescribed burning creates preferred foraging habitat patches for Gouldian finches within savanna fire mosaics.

Assessment of facilities and slaughter figures of livestock species in Oko-Oba central abattoir Ifako-Ijaye, Agege Lagos State, Nigeria

Abattoirs are needed to centralize slaughter processes and ensure surveillance of animal diseases at slaughter in order to avoid zoonotic transmission to humans through meat consumption. Inadequate facilities and hygiene at abattoirs can result in the contamination of meat and cause occupational hazards to workers. The objectives of this study were to assess the conditions of the facilities and the daily slaughter figures of livestock species at Oko-oba abattoir, Ifako-ijaye, Agege Lagos State. The study was conducted for three seasons from August 2020 to April 2021. A structured questionnaire was used to collect information on the study area, while daily visits, physical observation and interviews were used to collect data. Data collected were analyzed using descriptive statistics of frequencies and percentages. Cattle was the most commonly slaughtered species (92.34 %), followed by goat (6.34 %), sheep (1.15 %) and camel (0.18 %) in the late wet season (August - September). Cattle, goat, sheep and camel were slain in decreasing order during the early dry season (October - December) (90.17 %, 8.38 %, 1.40 % and 0.04 % respectively). In the late dry season (January - April), the cattle were recorded to have 88.00 %, goat 10.92 %, sheep 1.07 % and camel 0.01 %. It was determined that the season had no impact on the types of livestock slaughtered. Cattle were the most butchered species regardless of the seasons studied, followed by goats, sheep and camels. The abattoir also lacks several fundamental amenities that are expected of a standard abattoir, and those that are present are either non-functional or inadequate.

Pyric Herbivory and the Nexus Between Forage, Fire and Native and Introduced Large Grazing Herbivores in Australian Tropical Savannas

Earth’s tropical savannas typically support high biomass of diverse grazing herbivores that depend on a highly fluctuating resource: high-quality forage. An annual wet–dry cycle, fire and herbivory combine to influence forage quality and availability throughout the year. In the savannas of northern Australia, a depauperate suite of large native (marsupial) herbivores (wallaroos [Osphranter spp.] and the agile wallaby [Notamacropus agilis]) compete for resources with non-native large herbivores introduced in the late nineteenth century, particularly bovines (feral and managed cattle [Bos spp.] and feral water buffalo [Bubalus bubalis]) that now dominate the landscape. Anecdotal reports of recent population declines of large macropods and negative impacts of bovines highlight the need to better understand the complex relationship between forage, fire and abundance of native and introduced large herbivores. The pyric herbivory conceptual model, which posits complex feedbacks between fire and herbivory and was developed outside Australia, predicts that native and introduced large herbivores will both respond positively to post-fire forage production in Australian savannas where they co-occur. We used grazing exclosures, forage biomass and nutrient analyses and motion-sensor camera-trapping to evaluate the overall robustness of the pyric herbivory model in the Australian context, specifically whether forage quantity and quality are impacted by herbivory, season and fire activity, and which forage attributes most influence large grazing herbivore abundance. Forage quantity, as measured by live, dead and total herbaceous biomass and proportion of biomass alive, was higher inside herbivore exclosures, even at relatively low densities of herbivores. Forage quality, as measured by fibre content, was not affected by herbivory, however, crude protein content of live herbaceous biomass was greater outside herbivore exclosures. Recent fire was an important predictor of all measures of forage quantity and quality. Recent fire occurrence decreased overall quantity (biomass) but increased quality (decreased fibre content and increased crude protein content); late dry season fires resulted in forage with the highest crude protein content. The predictions of the pyric herbivory conceptual model are consistent with observations of the feeding behaviour of introduced bovines and some large macropods in northern Australian savannas, lending support to the global generality of pyric herbivory in fire-prone grassy biomes.

Resistance of termite mounds to variation in long-term fire regimes across semi-arid African savannas.

Fire regimes are expected to change with climate change, resulting in a crucial need to understand the specific ways in which variable fire regimes impact important contributors to ecosystem functioning, such as mound-building termites. Termite mounds and fire are both important agents of savanna ecosystem heterogeneity and functioning, but there is little understanding of how they interact across savanna types. We used very high-resolution LiDAR remote sensing to measure the size and distribution of termite mounds across approximately 1300 ha of experimental burn plots in four South African savanna landscapes representing a wide range of fire treatments differing in seasonality and frequency of burning. In nutrient-poor granitic savannas, fire had no impact on termite mound size, densities and spatial distributions. In nutrient-rich basaltic savannas with high mammalian herbivore abundance and intermediate rainfall, very frequent fires caused a decrease in termite mound size, whereas in arid nutrient-rich basaltic savannas, fires that occurred at intermediate frequencies and in transitional seasons (i.e. late dry season and late wet season) decreased the degree of spatial overdispersal exhibited by mounds. Overall, our results suggest that termite mounds are resistant to variation in fire seasonality and frequency, likely indicating that ecosystem services provided by mound-building termites will be unaffected by changing fire regimes. However, consideration of changes to termite mound size and distribution could be necessary for land managers in specific savanna types, such as nutrient-rich soils with high mammalian herbivore abundance.

Modelling the longitudinal distribution, abundance, and habitat use of the giant freshwater shrimp (Macrobrachium spinipes) in a large intermittent, tropical Australian river to inform water resource policy

Abstract Water development threatens rivers and their biodiversity. Amphidromous shrimp are particularly vulnerable as they require migration between freshwater and estuaries to complete their life cycle. The Fitzroy River is a large tropical intermittent river undergoing water development that is home to the amphidromous shrimp Macrobrachium spinipes (cherabin), yet little is known about its habitat use and flow‐ecology making it difficult to inform sustainable water‐take. We investigated habitat associations, distributional patterns suggestive of amphidromy, and the influence of water availability by sampling main channel and floodplain pools along a 350‐km river length during 2 contrasting flow years. Applying a size‐specific abundance model, we estimated abundance per size class, site, and year. We then predicted abundance at the landscape scale with remotely sensed water to reveal the impact of water availability on the meta‐population. Our model revealed that juveniles were in greatest abundance in downstream main channel pools, whereas adults were in greatest abundance in upstream floodplain pools. Abundance varied by year with lower numbers predicted in the low‐flow year. Longitudinal and habitat patterns remained when our pool‐level results were scaled to the landscape, and the positive relationship of abundance to wet‐season flow was strengthened. The predominance of smaller cherabin in the lower reaches of the river provides indirect support for an estuarine nursery and amphidromous life history; however, small individuals observed in landlocked pools, during late dry season suggests possible within‐river recruitment. The importance of water development policies that protect wet‐season flow and passage along the Fitzroy River is supported by this work. These types of policies are likely to be important for this and other amphidromous shrimp species across Australia, Southeast Asia and further afield. Further research detailing the species life history and describing flow–recruitment relationships will be important contributions to understanding this important taxonomic group and refining policies for current and future water resource development.

Reprint of: Influence of trees on landscape temperature in semi-arid agro-ecosystems of East Africa

In the Dodoma region of Tanzania, overexploitation of natural resources has led to a severe land degradation and, consequently, to the need to restore local ecosystems. Within the possible strategies, the farmer managed natural regeneration agroforestry is strongly being promoted in the area. To validate the utilisation of this practise, this research aims (i) to assess the benefits of trees on microclimate studying the relationship between land surface temperature (LST) and tree canopy cover (TCC) in farmlands and (ii) to propose an operative tree density threshold to be set as objective by restoration activities in the area. Data collected with an unmanned aerial vehicle were integrated with Landsat 8 and Sentinel 2 satellite imagery. LST was retrieved through the practical single channel algorithm and TCC was calculated with a supervised classification. Pixel-based analyses at a resolution of 30 m and 10 m were performed, and the resulting data statistically analysed through the coefficient of determination, the Kruskal–Wallis test, and the Dunn test. Results showed that the TCC of the surveyed areas was 5.1%, and a significant decrease in LST of 1.32 °C (p < 0.01) was found in the areas with the highest TCC, during the late dry season. From these preliminary analyses, a threshold of 10% TCC is suggested for farmlands in this agroecological zone to bring beneficial microclimate changes in terms of temperature. Considering the average plant phenotype characteristic of the area, it corresponds to a tree density of 50 trees ha−1.

NESTING OF THE GREATER YELLOW-HEADED VULTURE (CATHARTES MELAMBROTUS) IN EASTERN PERU

The Greater Yellow-headed Vulture (Cathartes melambrotus) is one of the less known cathartids (Cathartiformes, Cathartidae), especially in its reproductive biology, being the only species in the family that does not have nest description. Here I describe the discovery of one nest located in a cavity 55 m above the ground on a 70 m high x 130 m wide cliff at 1.230 masl. in the eastern rainforest of central Peru. The nest was found during late dry season (October 31, 2019), and contained a well-developed chick (50-60 days old) which was being fed by the parents. The habitat surrounding the nesting site presented thinned forests for shade of coffee crops, banana and citrus plantations and remnants of adult secondary forest in the streams.

Flexible drought deciduousness in a neotropical understory herb.

PremiseAdaptive divergence across environmental gradients is a key driver of speciation. Precipitation seasonality gradients are common in the tropics, yet drought adaptation is nearly unexplored in neotropical understory herbs. Here, we examined two recently diverged neotropical spiral gingers, one adapted to seasonal drought and one reliant on perennial water, to uncover the basis of drought adaptation.MethodsWe combined ecophysiological trait measurements in the field and greenhouse with experimental and observational assessments of real‐time drought response to determine how Costus villosissimus (Costaceae) differs from C. allenii to achieve drought adaptation.ResultsWe found that drought‐adapted C. villosissimus has several characteristics indicating flexible dehydration avoidance via semi‐drought‐deciduousness and a fast economic strategy. Although the two species do not differ in water‐use efficiency, C. villosissimus has a more rapid growth rate, lower leaf mass per area, lower stem density, higher leaf nitrogen, and a strong trend of greater light‐saturated photosynthetic rates. These fast economic strategy traits align with both field‐based observations and experimental dry‐down results. During drought, C. villosissimus displays facultative drought‐deciduousness, losing lower leaves during the dry season and rapidly growing new leaves in the wet season.ConclusionsWe revealed a drought adaptation strategy that has not, to our knowledge, previously been documented in tropical herbs. This divergent drought adaptation evolved recently and is an important component of reproductive isolation between C. villosissimus and C. allenii, indicating that adaptive shifts to survive seasonal drought may be an underappreciated axis of neotropical understory plant diversification.

Multi-temporal spectral reflectance of tropical savanna understorey species and implications for hyperspectral remote sensing

• Spectra of savanna understorey vegetation species over phenological seasons. • Separability of functional groups, and species, depended on season. • Informs species separation and timing for drone-based hyperspectral captures. • VNIR drone spectral range excludes foliar traits such as cellular water absorption. The relationship between species phenology and spectral separability is essential to determine the optimal remote sensing sampling period to maximise spectral separability of vegetation species. However, this relationship in many native grasses, introduced grasses and herbs, shrubs, and vine species in tropical savannas is unknown. We measured the in-situ hyperspectral response of monospecific vegetation stands of several understorey species representing different functional groups over phenological stages (throughout dry and wet seasons) using a non-imaging spectrometer. We present a spectral library of both native and introduced species of a tropical savanna environment. We analysed the data using continuum removal to highlight absorption features. Most understorey species displayed a photosynthetic spectral response with increased greenness at the end of the wet season that progressively declined as vegetation dried out. For some species, there were seasonally dependent differences in absorption features with spectral differences between the late wet and early dry season, and late dry and early wet seasons. We resampled the data to the spectral range typical of drone-mounted hyperspectral sensors (i.e., 150 bands between 400 and 1000 nm), which omits the water absorption features of the SWIR. These findings suggest an ideal sampling period for measuring outdoor canopy reflectance of understorey species, which will promote methodological improvements of hyperspectral data capture. The use of a VNIR only hyperspectral sensor will exclude the important regions of the spectrum for plant spectral identification including non-pigment bands for water, nitrogen and cellulose. The results have implications for determining the completeness of rehabilitation assessing reestablishment among indigenous species across mine sites under rehabilitation.

An analysis of the recent fire regimes in the Angolan catchment of the Okavango Delta, Central Africa

BackgroundThis paper presents an analysis of fire regimes in the poorly studied Angolan catchment of the Okavango Delta in Botswana. We used MODIS data to examine the frequency and seasonality of fires over 20 years (from 2000 to 2020) in three dominant vegetation types (miombo woodlands, open woodlands and grasslands, and short closed to open bushlands), and in areas where people were present, and where they were absent.ResultsThe median fire return intervals for both open woodlands and grasslands and short bushlands were relatively short (1.9 and 2.2 years respectively). In miombo woodlands, fires were less frequent (median return periods of 4.5 years). Human population density had no discernible effect on the fire return intervals, but about 14% of the miombo woodlands experienced no fires over 20 years. Ongoing shifting cultivation within miombo woodlands has led to structural changes and the introduction of fire into this vegetation type where fires were rare or absent in the past. About 12% of the miombo did not burn during the period examined where people were present, whereas close to 20% of the sites remained unburnt where people were absent. This suggests that people did not change the fire return interval in any of the vegetation types studied, but that they altered the amount of the landscape that is flammable in miombo vegetation. Fires occurred between June and September, with a peak in the late dry season (August and September).ConclusionsHistorical research indicates that late dry-season fires are detrimental to miombo woodlands, and our analysis suggests that degradation in parts of the catchment has led to the introduction of fire to this previously fire-free and fire-sensitive vegetation type. Deforestation of miombo woodlands, and the consequent introduction of fire, is a cause for concern with respect to the ecological stability of the Okavango Delta. Managers should therefore aim to protect the remaining closed-canopy miombo stands from further clearing and to attempt to shift the timing of burns to the early dry season to reduce their intensity.

The impact of alpha male replacements on reproductive seasonality and synchrony in white‐faced capuchins ( Cebus imitator )

Objectives Reproductive seasonality is typically associated with ecological factors, but it can also be related to social factors, such as alpha male replacements (AMR). Such events can produce distinct birth peaks outside of the ecological peak, potentially increasing hardship for mother and infant and ultimately reducing fitness. We examined the impact of AMRs on birth seasonality, birth synchrony, and infant survival in the Santa Rosa population of white-faced capuchins (Cebus imitator). Materials and Methods We analyzed 33 years of data on seven capuchin groups to test whether AMRs and births occur seasonally and whether birth seasonality changes following AMRs. Using sliding window analysis, we tested whether ecological conditions predict births in future months. We also tested whether birth period affects infant survival and likelihood of infanticide. Results AMRs shift birth seasonality from the ecological birth peak in the early wet season (late May–July) to a social birth peak during the late dry season (March–May), but they do not affect synchrony. In addition, we found that being born in the social peak significantly decreases infant survival relative to individuals born in the ecological and nonpeak periods. Discussion These findings suggest that Santa Rosa's predictable seasons can provide conception cues for female capuchins, but AMRs disrupt this ecological timing of conceptions. We suggest the increased infant mortality associated with the social birth peak is related to seasonal factors, including water scarcity and varying resource availability, and increased risk of infanticide, as the social birth peak overlaps with the AMR peak.

Smoke pollution must be part of the savanna fire management equation: A case study from Darwin, Australia

Savanna fire management is a topic of global debate, with early dry season burning promoted as a large-scale emissions reduction opportunity. To date, discussions have centred on carbon abatement efficacy, biodiversity and cultural benefits and/or risks. Here we use a case study of Darwin, Australia to highlight smoke pollution as another critical consideration. Smoke pollution from savanna fires is a major public health issue, yet absent so far from discussions of program design. Here, we assess the likely impacts of increased early dry season burning on smoke pollution in Darwin between 2004 and 2019, spanning the introduction and expansion of carbon abatement programs. We found increased smoke pollution in the early dry season but little change in the late dry season, contributing to a net annual increase in air quality standard exceedances. Geospatial analysis suggests this relates to increased burning in the path of early dry season trade winds. This study highlights the complex health trade-offs involved with any large-scale prescribed burning, including for carbon abatement.

Livestock feed markets across seasons in periurban areas of Niger: seller and buyer profiles, feed price and quality

Livestock productivity in West African Sahel is constrained by seasonal scarcity of feed and by its low quality in the dry season. Feed resources scarcity in the region has also been aggravated by the increase in livestock population, which has heightened the demand for feed, particularly in periurban areas. Livestock feed markets have thus sprung up in many cities and towns. To understand the dynamics of these markets, surveys were conducted in five of them in Maradi and five others in Niamey, Niger, in the early dry season (October-November 2019), late dry season (March-June 2020), and wet season (August-September 2020) with a semi-structured questionnaire. Results showed that diverse feed types were sold or bought, and mainly by adult male vendors or buyers, in both markets across seasons. The buyers gave as major reasons for purchasing livestock feed the insufficient household feed biomass, the poor-quality household feed, and the need for supplementary feeds to maintain and improve animal performance. Prices of livestock feeds at both markets varied significantly with season, market location and feed type. In both sites, prices of legume residues (cowpea hay, cowpea husk, groundnut haulm) were higher than the other feed types. Results further showed that there was no clear relationship between price and nutritional quality across seasons.

Integrated assessment of trypanosomosis challenge on cow health and milk based on The Gambia's agropastoralism

To improve understanding of African Animal Trypanosomosis (AAT) and associated host-parasite relationship's challenges on cow and milk, The Gambia was examined given its enzootic status. Based on an integrated assessment framework, semi-structured questionnaires which were pre-tested and then administered in five regions were used. Relationships among the investigated variables were statistically explored with Pearson chi-square test and strength of association quantified with Phi or Cramer's V coefficient. Rough coat, eye and nose discharge, loss of appetite and weight were more consistently observed as signs of AAT in infected lactating cows. Older cows with more than three calving (75.8%) were indicated as the most susceptible and there is no fixed number of times (85.2%) a cow is treated for AAT in a year. The most commonly recognized effect (91.7%) of AAT is milk reduction. Statistically significant positive but moderate relationship exist between milk reduction and late dry season (phi coefficient of 0.221), between milk contamination and early dry season (phi coefficient of 0.226), and also between wateriness and rainy season (phi coefficient of 0.220). Milk discolouration is not statistically related to any season with highest AAT infection rates. The need for integrated assessment of veterinary challenges based on factors such as herd affiliation status, ethnic affiliation, and farmers’ objectives before preventive veterinary and production interventions are designed or implemented is implied. Useful information to advance research in this direction are presented.

Short duration overnight cattle kraaling in natural rangelands: Does time after kraal use affect their utilization by wildlife and above ground grass parameters?

In east and southern Africa some private ranch owners are corralling (hereafter kraaling) cattle overnight for short periods (for example, seven days) in natural rangelands to create nutrient enriched hotspots which are attractive to large herbivores. However, the effect of season and time after kraal use (alt. age of nutrient enriched hotspots) on large herbivore use of these sites has not been examined. We collated the number of large herbivore sightings per day from camera traps during wet, early and late dry season in nutrient enriched hotspots of varying ages (1, 2, 3 and 4 years) and surrounding vegetation. In addition, above ground grass biomass and height in nutrient enriched hotspots was compared to that of the surrounding vegetation. Furthermore, we tested if repeated grazing in nutrient enriched hotspots stimulated grass compensatory growth. Large herbivore use of nutrient enriched hotspots was similar during wet, early and late dry season. Time after kraal use had a significant effect on mixed feeders (impala and African savanna elephant) utilization of nutrient enriched hotspots but not grazers (zebra and warthog) and browsers (giraffe and greater kudu). Both impala and African savanna elephants mostly used nutrient enriched hotspots one year after kraal use. Aboveground grass biomass and height were higher in surrounding vegetation than in nutrient enriched hotspots. Repeated clipping (proxy for grazing) resulted in compensatory aboveground grass biomass in nutrient enriched hotspots, which declined with time after kraal use. We concluded that nutrient enriched hotspots created through short duration overnight kraaling were important foraging sites for large herbivores.