Forest Savannah Research Articles

Diversity, habitat and activity patterns of mesocarnivore assemblages in an Afrotropical protected forest savannah mosaic of Central Cameroon

AbstractLittle is known about the diversity and ecology of mesocarnivores in the Mpem and Djim National Parks in central Cameroon. Therefore, we undertook a rapid assessment using camera traps from September 2021 to December 2021. The main objective of our study was to collect data on the diversity, abundance and relative frequency of mesocarnivores per habitat type and their activity period using camera traps with a distance sampling method. In 1700 trap nights, we recorded 53 events of seven mesocarnivores, all belonging to the family of Viveridae, Herpesdidae and Felidae which yield 3.12 mesocarnivores per 100 days. The black‐legged mongoose (Bdeogale nigripes, Pucheran, 1855) exhibited the highest capture rate (CR, 0.88). The long‐nosed mongoose (Xenogale naso, Winton, 1901) was found in all habitats class and was the more active mesocarnivore. The Shannon‐Weaver diversity index (H) showed a high diversity of species in the community with high diversity in the near primary forest. We obtained a lower dominance of one species over the other, a lower richness and a more even distribution of species between habitats. Our results suggest a possible spatio‐temporal niche partitioning between the species recorded, with blotched genet (Genetta maculata, Gray, 1830), showing no clear peak of activity. However, the rarefaction curve indicates that the effort expended was insufficient, suggesting that additional sampling is required to obtain a reasonable estimate of species richness within our community. The activity patterns of the recorded mesocarnivores were generally similar to those reported elsewhere but suggest some behavioural flexibility. Although all these species are listed as Least Concern by the IUCN, the low number of recorded events may indicate that mesocarnivores may be threatened in this area if effective conservation strategies are not implemented.

Echoes of the Past: Unveiling the Kharga Oasis’ Cultural Heritage and Climate Vulnerability through Millennia

The civilization and tangible cultural heritage of the Kharga Oasis has a historical precedence over that of the old Nile Valley civilization. Approximately 12,000 years ago, a significant prehistoric migration occurred from the Kharga Oasis to the Nile Valley. This event was motivated by climate change and the southward shift of the Inter-Tropical Convergence Zone (ITCZ), which caused a shift in Egypt’s savannah forests from abundant vegetation to an extremely dry desert. The present study investigates the progressive deterioration of the tangible cultural and civilized legacy of the Kharga Oasis over the course of several millennia, positing that this phenomenon can be attributed to the area’s vulnerability to paleoclimatic fluctuations. The evaluation of the Kharga Oasis’ susceptibility to climate change was predicated on the scrutiny of petroglyphs that were unearthed at different sites within the Oasis. This analysis was reinforced by paleoclimate information and radiocarbon dating (C14). The utilization of an interdisciplinary approach yielded significant insights into the dynamic climate patterns and their effects on the Kharga Oasis across temporal scales. The results illustrated a noteworthy alteration in climate, which caused the conversion of the Oasis terrain from being heavily wooded to becoming arid, mainly due to extended periods of drought. The present research postulates a novel and alternate hypothesis concerning the archaeological chronology of human habitation in the Kharga Oasis from ancient eras, predicated on the analysis of pictorial depictions on rock surfaces. The findings of this study made a noteworthy contribution to the current corpus of knowledge regarding the vulnerability of the ancient Egyptian society to the impacts of climate variability. Moreover, the petroglyphs’ depictions provided a distinctive viewpoint on the climatic fluctuations that occurred in the Sahara and North Africa throughout the Holocene epoch, as well as the fundamental causative factors.

Evaluation and phenotypic plasticity of taro [Colocasia esculenta (l.) Schott.] genotypes for nutrient and anti-nutrient composition.

The study was carried out to determine the nutritional and anti-nutritional composition of taro genotypes and also determine the phenotypic plasticity of the genotypes in two agro ecological zones in Ghana. The towns and zones were Bunso in the semi deciduous forest (an upland) and Tano Dumasi in the forest savannah transition agro-ecological (a waterlogged area) zone in the Eastern and Ashanti regions respectively.Two (2) freshly harvested corms of each genotype from each location were assessed for their nutritional (moisture, protein, carbohydrate, ash and fat) and anti-nutritional (phytate, oxalate and tannin) composition Data collected were subjected to analysis of variance and AMMI analysis using GenStat 12 edition to assess the effect of genotype, environment and their interaction on the traits studied. Phenotypic plasticity for the genotypes and the traits studied was also calculated. Pearson correlation was also conducted to assess the relationship between the traits studied. There were significant differences among the genotypes for nutrient and anti-nutrient composition except for percentage fat, indicating enough genetic variability among the genotypes, giving room for good selection progress for development of taro varieties. A higher magnitude of the environment over genotype and genotype by environment interaction observed indicates the influence of environment in the expression of the nutritional and anti-nutritional traits. Observed varied phenotypic plasticity among the genotypes for the nutrient and anti-nutrients composition also indicates varied adaptation of the genotypes to the environment. Genotypes BL/SM/115, CE/MAL/32 and CE/IND/16 and hybrids KAO19 × CE/MAL/32 and CE/IND/16×KAO19, CE/IND/16 × BL/SM/10, and CE/IND/16 × BL/SM/115 which recorded high nutrients and low anti-nutrients content and were stable across the environments can be released to farmers for cultivation. They could also be included in breeding programs for the development of enhanced nutritional quality of taro in Ghana.

Land use land cover (LULC) degradation intensity analysis of Guinea savannah and mosaic Forest savannah zones in Ghana

Land use land cover (LULC) degradation intensity analysis of Guinea savannah and mosaic Forest savannah zones in Ghana

Spatial variability of the occurrence of lesions on cattle carcasses in association with pre-slaughter factors in the forest–savannah transition zone

Spatial variability of the occurrence of lesions on cattle carcasses in association with pre-slaughter factors in the forest–savannah transition zone

Nutrients status and soil microbial biomass C and N in charcoal production sites of derived savannah forest of southwestern Nigeria

Deforestation and other anthropogenic activities, including charcoal production affect several microbial activities and nutrients availability and status in the savannah forest soil of southwestern Nigeria. However, understandings of the microbial activities and soil nutrients availability in these sites have not been thoroughly studied. Therefore, the study aims to clarify the charcoal production effects on the microbial biomass carbon and nitrogen, nutrients status of charcoal production sites and the surrounding soils. Soil samples were collected to determine the microbial biomass contents in carbon and nitrogen (BC and BN), organic carbon of the soil (SOC), total nitrogen (TN), ammonium and nitrate nitrogen [(NH4+-N) and (NO3N)] in the soil layers between 0–15, 15–30 and 30 – 45 cm, under different locations of charcoal production and non-production sites (CPS and NPS) respectively. We found out that SOC, TN, C/N ratio, Bc and BN and the ratios of Bc/SOC and BN/TN were significantly higher in the NPS than in the CPS. The SOC, TN, BC and BN and the ratios of Bc/SOC and BN/TN declined significantly (P ˂ 0.05) with increase in depth in the two sites under different locations. However, NH4+-N and NO3N contents in the NPS were significantly lower compared to the CPS. The results of the analysis indicate better soil nutrients in term of SOC and TN in the NPS than CPS. It is therefore posited that NPS is healthier and can sustain soil microbial activities than CPS. Although, NPS is lower in inorganic nitrogen contents determined, CPS has the potential to reduce leaching of inorganic nitrogen and increases its availability in the derived savannah agro-ecological region of southwestern Nigeria. Effort must be made to mitigate the large-scale conversions of the native derived savannah forests for traditional charcoal production that contributes to environmental pollution; it is therefore useful to consider biochar strategy in order to mitigate global warming and manage soil health and productivity.

Differing local‐scale responses of Bolivian Amazon forest ecotones to middle Holocene drought based upon multiproxy soil data

ABSTRACTUncertainty remains over local‐scale responses of ecotonal Amazonian forests to middle Holocene drying due to the scarcity, and coarse spatial resolution, of lacustrine pollen records. This paper examines the palaeoecological potential of soil phytoliths, stable carbon isotopes and charcoal for capturing local‐scale ecotonal responses of different types of Bolivian Amazonian forest to middle Holocene climate change. Soil pits 1 m deep were dug at ecotones between rainforest, dry forest, Chaco woodland and savannah, and sampled at 5–10 cm resolution. Both phytolith and stable carbon isotope records indicate stability of dry forest–savannah ecotones over the last ca. 6000 years, despite middle Holocene drought, revealing the dominance of edaphic factors over climate in controlling this type of ecotone. In contrast, δ13C data reveal that rainforest–savannah ecotones were more responsive to climate change, with rainforest likely replaced by drought‐tolerant dry forest or savannah vegetation during the mid‐Holocene, consistent with regional‐scale lacustrine pollen records. However, such shifts are not apparent in most of our phytolith records due to insufficient taxonomic resolution in differentiating rainforest from dry forest. Charcoal data show that ecotonal dry forests experienced greater fire activity than rainforests and that recent high fire activity at all forest sites is unprecedented since at least the middle Holocene.

Pangolin hunting and trafficking in the forest–savannah transition area of Cameroon

AbstractPangolins have long been hunted for food and for their scales, but information on local hunting strategies in African range countries and the patterns of pangolin trafficking around sourcing areas is limited. Such knowledge is vital to inform monitoring approaches and conservation interventions. We administered questionnaires to 367 people from 20 villages around two national parks in Cameroon to gain insights into local hunting practices, and trading and trafficking patterns. We found that tracking was the preferred method of hunting pangolins. Trapping was also used, and setting traps on fallen logs and near burrows improved the likelihood of catching pangolins. The white-bellied pangolin Phataginus tricuspis was the most traded species, and the giant pangolin Smutsia gigantea was the most sought after. We found no evidence of trade in the black-bellied pangolin Phataginus tetradactyla. Most respondents stated that pangolin prices had increased over the last 5 years, and scarcity of pangolins was the primary reason given for this increase. We identified a pangolin scale trafficking network operating from rural communities to neighbouring cities. Although most respondents recognized that hunting pangolins is illegal, c. 30% indicated that they were engaged in pangolin hunting.

Impact of COVID 19 on Digital Marketing: A Systematic Study on Sub Saharan African

The spread of the COVID-19 pandemic has had massive impacts on digital marketing, notably in Sub-Saharan Africa, which had been the preferred method of marketing in recent years. The term "Sub-Saharan Africa" is used to describe the African countries south of the Sahara Desert. This includes the eco-region of the Sahel, which lies between the Sahara and the African tropical and forest savannah zones, and the island states off Africa's western and eastern borders. South Africa, Sudan, Nigeria, Kenya, and Angola are just a few of the 48 countries that make up Sub-Saharan Africa. This study seeks to determine the impact of COVID 19 on digital marketing in Sub-Saharan Africa. Utilizing systematic review and, especially, the quick review approach, this objective was accomplished. The study concluded that COVID 19 had both positive and negative impacts on digital marketing in Sub-Saharan Africa. Sales, advertising, and promotion via digital channels have increased, which is a positive development. As a result of the lockdown and the corona virus epidemic, people are more likely to conduct business on the internet. Enhanced internet marketing has helped firms in Sub-Saharan Africa expand their clientele, revenue, and profits.
 Unfortunately, many digital marketing firms' reputations were damaged because some users abused their access to various online services by engaging in fraudulent activities during the epidemic. Ad, marketing, promotional, and media spending have all been adjusted as a result of the global COVID-19 epidemic. The study concluded and suggested that Sub-Saharan businesses and government institutions must be courteous, employ digital marketing, and respond to consumers during cultural events like the COVID-19 pandemic. To keep consumers, brands must fix the problem while being positive. Adjusting marketing campaign and content timings, advertising language and visuals, and being aware of customers' growing concern may do this. Under the global pandemic, Sub-Saharan African (SSA) firms must rely more on digital sales or e-commerce to flourish.

Plasmodium malariae contributes to high levels of malaria transmission in a forest–savannah transition area in Cameroon

BackgroundMalaria control efforts are highly skewed towards Plasmodium falciparum while overlooking other Plasmodium species such as P. malariae. A better understanding of the role of Plasmodium species other than P. falciparum is needed to strengthen malaria elimination initiatives. The aim of the present study was to elucidate the contribution of P. malariae to malaria transmission in Cameroon.MethodsThe study was conducted in the Ngatti Health District, a forest–savannah transition area in the Adamawa Region, Cameroon. A total of 497 individuals aged from 1 to 85 years were diagnosed with malaria in November 2020 using a rapid diagnostic test (RDT) and microscopy. Adult mosquitoes were collected between September 2019 and March 2020 by indoor aspiration and identified morphologically and molecularly. The infection status of Plasmodium spp. was also determined by quantitative PCR, and dried blood spots were collected from 156 participants with the aim to detect different Plasmodium species by nested PCR.ResultsThe overall Plasmodium prevalence was 50.3%, 51.8% and 64.7%, as detected by microscopy, the RDT and PCR, respectively. Based on the PCR results, P. falciparum was the most prevalent species (43%); followed by co-infections P. falciparum/P. malariae (17%), P. falciparum/P. ovale (1.3%), P. falciparum/P. ovale/P. malariae (1.3%); and then by P. malariae mono-infection (2.5%). The same trend was observed using microscopy, with 35% of participants infected with P. falciparum, 11% co-infected with P. falciparum/P. malariae and 4% infected with P. malariae. The prevalence and parasite density of malaria infection varied significantly with age group (P < 0.05), with the highest prevalence rate observed in children aged 6–10 years (P = 0.0001) while the density of Plasmodium infection increased significantly in children aged < 5 years compared to the other age groups (P = 10−3). Among the 757 Anopheles mosquitoes collected, 737 (97.35%) were An. funestus sensu stricto, 15 (1.9%) were An. gambiae and 5 (0.6%) were An. hancocki. The Plasmodium species recorded at the head/thorax level were P. falciparum and P. malariae, with a sporozoite infection rate of 8.4%; the highest sporozoite infection rate was recorded at Mibellon village (13.6%).ConclusionThe results of this study reveal the significant contribution of P. malariae, in addition to P. falciparum, to the high malaria transmission rate in this region. These findings highlight the need to deploy initiatives to also tackle this Plasmodium species to eliminate malaria in the region.Graphical

Legal provision on the use of exotic species in forest restoration: eucalyptus leaf decomposition in different Brazilian savannah formations

The Brazilian federal law has established norms for vegetation protection in 2012 for the planting of exotic species for the restoration of altered areas. Given the large number of areas to be recovered in the savannah biome in Brazil (e.g., Cerrado), the use of fast-growing species and high biomass production (e.g., Eucalyptus spp.) has been earnestly considered. However, the recommendation of this exotic species must be scientifically supported. This work aimed to evaluate the decomposition process of eucalyptus leaf litter in three different phytophysiognomies in the Cerrado biome (Brazilian Savannah) with three different formation type: Typical Cerrado, Savannah Forest, and Gallery Forest. The leaf decomposition was evaluated by the litter bags that were collected from October 2017 to October 2018. The difference between the initial mass and the masses was evaluated at the different collection periods. After one year, we determined the decomposition rate and the constant k using the exponential equation proposed by Olson. The decomposition rate of eucalyptus leaves was high in the three Cerrado formations. The shortest decomposition time was observed in Gallery Forest. The results showed that the main types of Cerrado formation effectively assimilate the organic material to be deposited in the soil. Thus, the study demonstrated the feasibility and legal provision of using exotic species, e.g., eucalyptus in the arduous mission of recovering degraded forest environments

Reservoir sedimentation and spatiotemporal land use changes in their watersheds: the case of two sub-catchments of the White Volta Basin.

Reservoir storage is compromised by sedimentation for which reason it has become an important matter in reservoir operation and management. While many studies have investigated sediment deposition rate in reservoirs, few have analyzed reservoir sedimentation from their catchment's land use change perspective. Based on bathymetric survey conducted on two reservoirs in the White Volta Basin in 2020 and analysis of four Landsat satellite imagery (1986, 1996, 2006, and 2020) within their watersheds, this study assessed the land cover change within the watersheds to draw inferences on the rate of sedimentation of the reservoirs located downstream of their catchments. The results revealed rapid sedimentation in the small-sized reservoir (Vea), with an annual sedimentation rate of 0.304% and a nominal sedimentation rate of 0.17% for the mid-sized reservoir (Tono). Furthermore, the savannah forest within the Vea catchment declined drastically from 29.4% (1985) to 9.9% (2020) influenced by the rapid expansion of farmlands from 18.7% to 47.9% within the same period, respectively. On the other hand, the savannah forest within the Tono catchment declined from 34.7% (1985) to 21.6% (2020) due to farmland expansion from 19.2% to 39% within the same period, respectively. The higher sedimentation rate observed in the small-sized reservoir was observed to be worsened by extensive tree cover removal in its catchment. Therefore, land cover characteristics within a watershed have a significant bearing on the rate of sedimentation in the reservoirs located downstream of their catchment. Hence, adopting a multi-sectorial approach to dealing with land use management is necessary to sustain reservoirs' storage.

Cashew expansion holds potential for carbon stocks enhancement in the forest-savannah transitional zone of Ghana

Despite the scientific contributions of earlier studies to the understanding of shifts in land-use to cashew in the forest-savannah transition zone, some questions remain unanswered: (1) what is the extent of landscape-level conversions associated with cashew? (2) could the expansion of cashew in the forest-savannah transitional zone potentially serve as a carbon mitigation strategy relative to other land uses at the landscape level? and (3) how does the land use dynamics associated with cashew development hold implications for Ghana’s climate change mitigation strategies? The Wenchi Municipality was used as a case study. Landsat images for 2000, 2015 and 2020 were classified to produce land cover maps using the random forest algorithm to overall accuracies of 72.6 %, 86.9 % and 91.2 %, respectively. The InVEST software was used to estimate the carbon sequestered by each land cover class in the landscape. Finally, 150 cashew farmers, four focus group discussions and key experts were interviewed. The results show that cashew plantations had increased in the Municipality by 31103.05 ha between 2000 and 2020. The shift in land use towards cashew increased the Above Ground Carbon from 599956.73 tons to 1039402.32 tons between 2000 and 2020, representing 696219.15 tons (883.5 %) increase in the Municipality. According to the farmers, the shift in land use to cashew was mainly due to the available ready market and relative higher income. This suggests that, there is great potential for mitigating climate change in the forest-savannah transitional zone using cashew. Hence, Ghana needs to explore the gains associated with cashew plantations, particularly as it transforms low-income crops with challenging post-harvest and marketing constraints into relatively lucrative income generation cashew, which has major implications for improvements in livelihood and co-benefits for carbon stocks enhancement. Ultimately, as Ghana rolls out its Nationally Determined Contributions implementation among other forestry sector climate change mitigation interventions, it is important to consider the role of cashew as a major contributor to carbon stocks enhancement within the Forest–Savannah transitional zone. This study provides major decision support for formulating policies, interventions, and measures to promote climate change and livelihood improvement opportunities while rolling out safeguard measures to prevent further conversion of relatively high carbon stocks landscapes, such as the savannah woodlands within the forest-savannah transitional zone.

The resting behavior of malaria vectors in different ecological zones of Ghana and its implications for vector control

BackgroundIn sub-Saharan Africa there is widespread use of long-lasting insecticidal nets and indoor residual spraying to help control the densities of malaria vectors and decrease the incidence of malaria. This study was carried out to investigate the resting behavior, host preference and infection with Plasmodium falciparum of malaria vectors in Ghana in the context of the increasing insecticide resistance of malaria vectors in sub-Saharan Africa.MethodsIndoor and outdoor resting anopheline mosquitoes were sampled during the dry and rainy seasons in five sites in three ecological zones [Sahel savannah (Kpalsogo, Pagaza, Libga); coastal savannah (Anyakpor); and forest (Konongo)]. Polymerase chain reaction-based molecular diagnostics were used to determine speciation, genotypes for knockdown resistance mutations (L1014S and L1014F) and the G119S ace1 mutation, specific host blood meal origins and sporozoite infection in the field-collected mosquitoes.ResultsAnopheles gambiae sensu lato (s.l.) predominated (89.95%, n = 1718), followed by Anopheles rufipes (8.48%, n = 162) and Anopheles funestus s.l. (1.57%, n = 30). Sibling species of the Anopheles gambiae s.l. revealed Anopheles coluzzii accounted for 63% (95% confidence interval = 57.10–68.91) and 27% (95% confidence interval = 21.66–32.55) was Anopheles gambiae s. s.. The mean resting density of An. gambiae s.l. was higher outdoors (79.63%; 1368/1718) than indoors (20.37%; 350/1718) (Wilcoxon rank sum test, Z = − 4.815, P < 0.0001). The kdr west L1014F and the ace1 mutation frequencies were higher in indoor resting An. coluzzii and An. gambiae in the Sahel savannah sites than in the forest and coastal savannah sites. Overall, the blood meal analyses revealed that a larger proportion of the malaria vectors preferred feeding on humans (70.2%) than on animals (29.8%) in all of the sites. Sporozoites were only detected in indoor resting An. coluzzii from the Sahel savannah (5.0%) and forest (2.5%) zones.ConclusionsThis study reports high outdoor resting densities of An. gambiae and An. coluzzii with high kdr west mutation frequencies, and the presence of malaria vectors indoors despite the use of long-lasting insecticidal nets and indoor residual spraying. Continuous monitoring of changes in the resting behavior of mosquitoes and the implementation of complementary malaria control interventions that target outdoor resting Anopheles mosquitoes are necessary in Ghana.Graphical abstract

Three spatially separate records confirm the presence of and provide a range extension for the giant pangolin Smutsia gigantea in Kenya

AbstractPangolins are some of the most overexploited but least studied mammals. The giant pangolin Smutsia gigantea is the largest of the eight pangolin species, measuring up to 180 cm in length and weighing up to 40 kg. It is a nocturnal, solitary species that occurs at low densities and little is known regarding its biology and ecology. It is distributed widely across the rainforests and forest savannah mosaics of equatorial Africa but its exact range extent is unknown. Apart from a single record in Kenya predating 1971, the eastern limit of its range was thought only to extend to central Uganda and western Tanzania. Here we present three spatially separate records confirming the presence of this species in Kenyan Afromontane forests. The three records are c. 120 km apart and c. 500 km east of the nearest confirmed giant pangolin population in Uganda. These records represent a significant range extension for the species and highlight the biodiversity and conservation importance of the Afromontane forests of western Kenya.

Impact of rainfall variability and land-use changes on river discharge in Sanaga catchment (forest–savannah transition zone in Central Africa)

Abstract Climate change/variability and land-use changes are the main forcings of river discharges variability. However, an understanding of their simultaneous impacts on river discharges remains limited in some parts of the world like in Central Africa. To shed light on this issue, the objective of this article was to investigate the effects of rainfall variability and land-use changes on river discharges in the Sanaga watershed (at Song Mbengue and Nachtigal gauging stations) and some of its sub-watersheds (Mbakaou, Lom Pangar, Magba and Bamendjing) over the 5 or 7 recent decades (depending on the data availability). To achieve this goal, hydrometeorological data of the Sanaga watershed and sub-watersheds were analyzed using the Pettitt and Mann-Kendall tests. Likewise, land-use changes in the watershed and sub-watersheds were also analyzed using supervised classifications of Landsat satellite images of the watersheds at two periods (1984 and 2020). The results show that annual rainfall decreased throughout the Sanaga watershed. This decrease is only statistically significant for the Sanaga watershed at Nachtigal (−5%), for which the study focused on relatively longer hydropluviometric series, including the 1950 and 1960s (wet decades). However, although the rainfall decreased in this watershed, the flows increased insignificantly according to the tests used in most cases. The 2010s seems particularly concerned by this increase, including in the Sanaga watershed at Nachtigal, where the general trend is downward. The flows increase in the Sanaga watershed would be the consequence of the increase in impervious areas in the latter (between +181.3 and +1,300% for built and roads and between +4.1 and +11.9% for bare soils), which would compensate for the drop in precipitation by increasing runoff. These results could be used for long-term planning of water demand and use in this watershed, as well as for improving future simulations of flows.

Phenotypical characterization of African savannah and forest elephants, with special emphasis on hybrids: the case of Kibale National Park, Uganda

AbstractThe IUCN now recognizes the savannah Loxodonta africana and forest Loxodonta cyclotis elephants to be separate species. Despite ecological, behavioural and morphological differences, and different habitat ranges, genetic studies confirm that the two species and hybrids coexist in forest–savannah ecotones. However, the hybrid phenotypes have not yet been described. In this survey we examined whether the phenotypes of the two species and of hybrids can be distinguished. In the first step, we used a machine learning algorithm (K-nearest neighbours) to compare 296 reference images of African elephants from five forest areas and six savannah areas where hybrids have not been recorded, confirming that six morphological criteria can be used to distinguish the species with more than 90% confidence. In the second step, we analysed 1,408 videos of elephants from 14 camera traps in Sebitoli, in Kibale National Park, Uganda, part of the main hybridization area. We used a multiple correspondence analysis and a species assignment key, highlighting the presence of three categories of phenotypes. Compared to the savannah and forest phenotypes (36.8 and 12.1%, respectively), the intermediate phenotypes, which could include hybrids, were more frequent (51.1%). Further studies combining morphology and genetics of the same individuals will be necessary to refine this species assignment key to characterize phenotypes confidently. This non-invasive, fast and inexpensive phenotypical-based method could be a valuable tool for conservation programmes.

Lidar reveals pre-Hispanic low-density urbanism in the Bolivian Amazon

Archaeological remains of agrarian-based, low-density urbananism1–3 have been reported to exist beneath the tropical forests of Southeast Asia, Sri Lanka and Central America4–6. However, beyond some large interconnected settlements in southern Amazonia7–9, there has been no such evidence for pre-Hispanic Amazonia. Here we present lidar data of sites belonging to the Casarabe culture (around ad 500 to ad 1400)10–13 in the Llanos de Mojos savannah–forest mosaic, southwest Amazonia, revealing the presence of two remarkably large sites (147 ha and 315 ha) in a dense four-tiered settlement system. The Casarabe culture area, as far as known today, spans approximately 4,500 km2, with one of the large settlement sites controlling an area of approximately 500 km2. The civic-ceremonial architecture of these large settlement sites includes stepped platforms, on top of which lie U-shaped structures, rectangular platform mounds and conical pyramids (which are up to 22 m tall). The large settlement sites are surrounded by ranked concentric polygonal banks and represent central nodes that are connected to lower-ranked sites by straight, raised causeways that stretch over several kilometres. Massive water-management infrastructure, composed of canals and reservoirs, complete the settlement system in an anthropogenically modified landscape. Our results indicate that the Casarabe-culture settlement pattern represents a type of tropical low-density urbanism that has not previously been described in Amazonia.

Between forest and croplands: Nocturnal behavior in wild chimpanzees of Sebitoli, Kibale National Park, Uganda.

Some animal species have been presumed to be purely diurnal. Yet, they show flexibility in their activity rhythm, and can occasionally be active at night. Recently, it has been suggested that chimpanzees may rarely engage in nocturnal activities in savannah forests, in contrast to the frequent nocturnal feeding of crops observed at Sebitoli, Kibale National Park, Uganda. Here we thus aimed to explore the factors that might trigger such intense nocturnal activity (e.g. harsher weather conditions during daytime, low wild food availability or higher diurnal foraging risk) in this area. We used camera-traps set over 18 km2 operating for 15 months. We report activities and group composition from records obtained either within the forest or at the forest interface with maize fields, the unique crop consumed. Maize is an attractive and accessible food source, although actively guarded by farmers, particularly during daytime. Out of the 19 156 clips collected, 1808 recorded chimpanzees. Of these, night recordings accounted for 3.3% of forest location clips, compared to 41.8% in the maize fields. Most nocturnal clips were obtained after hot days, and most often during maize season for field clips. At night within the forest, chimpanzees were travelling around twilight hours, while when at the border of the fields they were foraging on crops mostly after twilight and in smaller parties. These results suggest that chimpanzees change their activity rhythm to access cultivated resources when human presence and surveillance is lower. This survey provides evidence of behavioral plasticity in chimpanzees in response to neighboring human farming activities, and emphasizes the urgent need to work with local communities to mitigate human-wildlife conflict related to crop-feeding.

Height-Diameter Relationship of Some Forest Species Exploited for Wood in the Natural Tropical Forest of the Congo Basin

To enrich knowledge on the growth dynamics of commercial forest species in the Congo Basin, a study was conducted in Cameroon, within a community forest in savannah forest transition zone (Zone 1) and within FMU 10 052 in dense semi-deciduous humid forest (Zone 2). It aimed to obtain, in 8 species, the height (H) of the tree from its diameter (D) more accessible: Entandophragma cylindricum (Meliacea), Eribroma oblongum, Sterculia rhinopetala et Triplochiton scleroxylon (Malvaceae); Erythrophleum suaveolens et Piptadeniastrum africanum (Fabaceae), Milicia excelsa (Moraceae) et Terminalia superba (Combretaceae). The destructive method was used. After felling and flushing out a tree, the dendrometric parameters were measured and/or calculated. In Zone 1, 6 species including T. scleroxylon were calibrated using 30 trees of each. In Zone 2, 45 trees of E. cylindricum, 99 of E. suaveolens and 82 of T. scleroxylon constituted the sample. At the 5% threshold (95% confidence interval), the height-diameter relationship is a linear model. In all species, the height of a tree is predicted by measuring its diameter through linear regression. In Zone 1 regression equation is: H(m) = 28.13 + 19.09 * D(m) for T. scleroxylon; H(m) = 12.35 + 30.38 * D(m) for S. rhinopetala; H(m) = 23.09 + 26.42 * D(m) for E. oblongum; H(m) = 14.86 + 20.92 * D(m) for P. africanum; H(m) = 14.98 + 24.78 * D(m) for T. superba and H(m) = 1.55 + 32.37 * D(m) for M. excelsa. In Zone 2, the relationship is: H(m) = 27.40 + 14.21 * D(m) for T. scleroxylon; H(m) = 7.79 + 20.18 * D(m) for E. cylindricum and H(m) = 20.08 + 9.74 * D(m) for E. suaveolens (probability associated with F < 0.0001). The influence of site parameters (biotic and abiotic) on the height-diameter relationship should be more studied in multilayers forests specifically in the Congo Basin.