Mount Cameroon Research Articles

Pollution of Water Resources by Agrochemicals in the Agroindustrial Areas at the South Western Flank of Mount Cameroon

This study aimed to assess the contribution of certain constituents of soluble agrochemical residues to surface and groundwater pollution in the study area. The constituents studied included Dissolved Oxygen (DO), Nitrate (NO3 - ), Phosphate (PO4 2-), Cadmium (Cd), Lead (Pb), and Nickel (Ni) in various water sources. Forty water samples were collected from both surface and groundwater. In-situ electronic meter measurements were used to determine the DO levels. The laboratory methods of Nitrogen Distillation and spectrophotometry were employed to measure the concentrations of NO3 - and PO4 2-, respectively. The concentrations of heavy metals were determined using Atomic Absorption Spectrometry. The results obtained during the wet season indicated that DO, NO3 - , and PO4 2- levels were within permissible limits. However, for Cd, Pb, and Ni, a significant proportion of values exceeded the permissible limits during this season (Cd: 95%, Pb: 95%, Ni: 35%), suggesting possible contamination of the water sources. Conversely, during the dry season, all parameters were within permissible limits, except for Pb, where 95% of its values exceeded the limit. These findings conclude that the application of agrochemicals in the agro-industrial areas has a notable impact on water resources, particularly during the wet season.

Association between malaria and undernutrition among pregnant women at presentation for antenatal care in health facilities in the Mount Cameroon region.

In resource limited settings, malaria and undernutrition are major public health problems in pregnancy. Therefore, this study assessed the association between malaria infection and undernutrition among pregnant women in the Mount Cameroon area. This cross-sectional study enrolled 1,014 pregnant women consecutively over a year. A structured questionnaire was used to collect socio-demographic information and clinical data. Maternal nutrition was assessed using dietary diversity (DD). Peripheral blood samples collected were used for the diagnosis of malaria parasitaemia by microscopy whereas haemoglobin (Hb) levels were determined using an Hb meter. Logistic regression was used to determine factors associated with malaria and dietary diversity. The prevalence of malaria infection and undernutrition was 17.8% and 89.6% respectively. In addition, of those infected with malaria, geometric mean parasite density was 301/μL of blood (range: 40-9280) while mean DD score was 3.57±0.82 (range: 1-7). The odds of being infected with malaria parasitaemia was highest among women enrolled in the rainy season (OR = 1.58, P = 0.043), who were farmers (OR = 2.3, P = 0.030), had a household size of < 4 individuals (OR = 1.48, P = 0.026) and who were febrile (OR = 1.87, P < 0.001). Also, attending clinic visits in Mutengene Medical Centre (OR = 2.0, P = 0.012) or Buea Integrated Health Centre (OR = 2.9, P = < 0.001), being < 25 years (OR = 2.4, P = 0.002) and a farmer (OR = 10.6, P = 0.024) as well as < 4 clinic visits (OR = 1.62, P = 0.039) were identified as predictors of undernutrition. Furthermore, the association between malaria and DD was statistically significant (P = 0.015). In this study, undernutrition was highly frequent than malaria infection. Thus, there is an urgent need to improve maternal awareness through nutritional counselling and health campaigns on the benefits of consuming at least five food groups. Besides, improved maternal dietary nutrient intake is likely to have impact on the burden of malaria parasite infection.

Geochemical characterisation of mangrove sediments in Tiko (SW, Cameroon, West Africa): Implication for provenance, paleoweathering and sediment maturity

Geochemistry was performed on clastic core sediments from the Tiko Mangroves estuary, South western region of Cameroon, to categorise the rock source composition, tectonic setting, past weathering intensity of the source area in relation to past climate and sediment maturity in relation to sedimentary cycle. Plots of La/Co, La/Sc, Cr/Th, discriminant function (DF1&2), TiO2vs Al2O3 and TiO2 vs Zr point to an acid (felsic) and mixed (intermediate) rock source composition for the Tiko sediments. The acid composition portrayed by the sediments is also confirmed by their LREE (Light rare earth elements) abundance, and a negative Europium anomaly on chondrite normalisation, while the intermediate (mix) composition reflects the multiple sources of the sediments (Douala Basin and basaltic debris from Mount Cameroon). Binary plots Discriminant function (A-P) M, and Discriminant function (A-P) MT signpost active tectonic domain for the studied sediments, that resulted from the tectonothermal of the Pan African orogenic history and eruptive activity of the mount Cameroon. The weathering indexes denoted as CIX (chemical index of weathering) and PIX (plagioclase index of weathering) for the Tiko sediments advocate an intense source area weathering in a humid hot climate. The PIX advocate a high-level plagioclase lixiviation. The low values of ICV (index compositional variation) less than 1 (<1) couple with correlation plots Zr/Sc vs Th/Sc, and Zr vs (La/Yb)N confirms that Tiko mangrove sediments are matured recycled sediments with compositional variations. This is the first comprehensive provenance study of mangrove ecosystem sediments in Cameroon.

The Influence of Organic Matter on Phosphorus Fixation in Soils from the Eastern Flank of Mount Cameroon

The maximum phosphate fixation (KF) and phosphorus sorption capacity (PSC) of soil samples collected from the surface and sub-surface horizons of five volcanic soil profiles from the eastern flank of Mount Cameroon were investigated before and after organic matter removal. The aim of this research was to investigate the influence of soil organic matter (OM) on phosphorus (P) fixation. The removal of soil OM from the soil samples was accomplished by the use of sodium hypochlorite. Phosphorus fixation studies were performed on the treated and untreated soil samples using calcium chlorite as the background electrolyte. Fixation data were interpreted with Freundlich adsorption isotherm. The results indicated that the removal of OM had an influence on both KF and PSC. Removal of soil OM decreased PSC and increased KF for all soils. The inhibition of aluminium oxide and the reduction of soil surface area after the removal of OM were the justifications for the increase in P fixation.

Determination of groundwater potential zones on the eastern slope of Mount Cameroon using geospatial techniques and seismoelectric method

In complex hard rock terrain where the population suffers from water scarcity, the use of site-specific single-method surface geophysical surveys to prospect for groundwater is a common practise. However, this has not completely solved the problem of drilling dry wells. To combat this failure, geospatial data and the analytical hierarchy process (AHP) are being used as supporting techniques to increase the chance of success. This study had the aim of generating a groundwater potential zones (GWPZ) map of the complex strato-volcanic terrain of Buea by integrating geospatial techniques, AHP, and the seismoelectric method. Five factors influencing groundwater recharge were used to define the groundwater potential zones. Via the AHP and weighted overlay methods, five classes of groundwater potential zones were delineated: very poor, poor, moderate, good, and very good. More than half of the study area has good to very good groundwater potential. Lastly, the GWPZ model is validated with an iso-conductivity map from a seismoelectric survey and existing static water level data. The iso-conductivity map revealed four main conductivity zones that correlate positively with the GWPZ map. The northwestern part of the study area is characterised by moderate groundwater potential, poor formation conductivity, and dry boreholes. There is an uneven distribution of groundwater and variable water table depth in the area. The results of this study are very encouraging, and the integrated approach used has proven to be efficient in determining groundwater potential zones in complex volcanic terrain.

Pselaphinae of the Cameroon Volcanic Line. Part 3. A new genus of Goniacerini (Coleoptera: Staphylinidae: Goniaceritae) from Mount Cameroon.

The new genus and species, Ewoma longiscapa gen. et sp. nov. of the pselaphine tribe Goniacerini based on specimens collected on Mount Cameroon are described and illustrated. The taxonomic position of the new genus within the tribe Goniacerini is discussed. The list of all genera of Goniacerini of sub-Saharan continental Africa with the number of species and the distribution as well as the list of all species known from Western Africa are given. The short overview of our knowledge of studies of the Pselaphinae of the sub-Saharan continental Africa is also provided.

Genomic analysis of Plasmodium falciparum isolates across different altitudinal zones along the slope of Mount Cameroon

BackgroundMalaria elimination is threatened by the emergence and rapid spread of drug resistance. Understanding the demographic history of Plasmodium falciparum and the genetic basis of adaptation to antimalarial treatment and host immunity is critical to elimination efforts. This study sought to characterize the diversity of P. falciparum isolates across different altitudes along the slope of Mount Cameroon.MethodologyUsing the Illumina next-generation sequencing platform P. falciparum isolates from low, intermediate and high altitudes along the slope of Mount Cameroon were studied to determine their genetic diversity, population structures, and signatures of selection in known drug resistance alleles.ResultsA total of 77,253 single-nucleotide polymorphisms were identified from 220 quality P. falciparum clinical isolates from high (24,214), intermediate (24,426), and low (28,613) altitude. About 49%, 48.2% and 30% of the parasite isolates from high, intermediate, and low altitudes, respectively had FWS values &amp;gt; 0.95 indicative of dominant mixed genotype infections and low population sub-structure with high potential for out-crossing. No significant difference was observed in within-host diversity while population structure analysis did not separate the isolates in the three major altitudinal groups by PCA, FST and admixtures, suggesting bidirectional gene flow among the populations. A total of 94 antigenic genes under balancing selection were detected in the area including vaccine candidate gene ama1, eba175, msp1, trap, dblmsp, and clag2. Moreover, 17 of these genes were identified to be under both recent positive directional and positive balancing selection including the prominent host immune target genes surfin 8.2, trap, and ama1. Recent directional selection analysis using integrated standardized haplotype score (iHS) did not detect any selection signatures in the Pfdhfr, Pfdhps, Pfmdr1, and PfK13 genes. Furthermore, no PfKelch13 validated mutation associated with artemisinin resistance was identified in this study and no structural divergence was noticed among the P. falciparum parasite populations across different altitudes around the Mount Cameroon region.DiscussionFindings revealed high genetic diversity and low population structure suggesting that malaria transmission remain high in the study area and parasite populations circulating around the slope of Mount Cameroon are homogenous.

Anaemia, iron deficiency and inflammation prevalence in children in the Mount Cameroon area and the contribution of inflammatory cytokines on haemoglobin and ferritin concentrations: a cross sectional study

BackgroundIron deficiency (ID) and anaemia of inflammation (AI) coexist where infections and nutritional deficiencies are common. The aim of this study was to determine burden of ID, anaemia, inflammation and AI in children in malaria endemic Limbe, Mount Cameroon as well as decipher the contribution of some inflammatory cytokines on the concentration of haemoglobin and ferritin.MethodsA total of 520 children aged ≤ 15 years old from the Limbe Health District (LHD) were randomly selected and examined in a cross-sectional study for iron deficiency, anaemia, inflammation and inflammation anaemia. Collected blood samples were used for full blood count and inflammatory marker analyses with the aid of a haemoanalyzer and ELISA machine, respectively. Spearman’s rank correlation analysis was used to determine the correlation between cytokines and haemoglobin while multiple linear regression analysis was used to evaluate the effects of inflammatory cytokines on haemoglobin and ferritin concentrations.ResultsThe overall prevalence of anaemia, ID, IDA, inflammation and AI were respectively, 67.5%, 34.6%, 12.9%, 63.1% and 30.2%. Children aged 12‒15 years (P = 0.001), enrolled from the community (P < 0.001), whose parents are civil servants (P < 0.001), living in a home with 6‒10 occupants (P = 0.016), afebrile (P < 0.001) and malaria negative (P = 0.007) had the highest prevalence of ID while, children ≤ 5 years old (P = 0.001), with a family size of 1‒5 occupants (P = 0.033) had the highest prevalence of AI. Haemoglobin concentration positively correlated with concentrations of IFN-γ (P < 0.001), TNF-α (0.045) and ferritin (P < 0.001) while a negative correlation was observed with IL-10 (P = 0.003). In the multiple linear regression analysis only IL-6 significantly (P = 0.030) influenced haemoglobin concentration.ConclusionsWhile IL-6 is of significance in the pathology of anaemia, iron deficiency and anaemia of inflammation are of moderate public health concerns in the Mount Cameroon area. Hence, appropriate intervention against anaemia, ID and AI should be directed at children ≤ 5 years and counterparts > 10 years old that bear the highest burden.

English

The survival of Protected Areas (PAs) in Cameroon is very much dependent on alternative economic benefits derived by local people living around these areas. This study was set out to assess the contributions of Mount Cameroon National Park (MCNP) activities to livelihood of the local people. To achieve this, a household survey was conducted using simple random sampling technic where each household was given equal opportunity of being selected to take part in the survey. Line transects questionnaires and a selection of some Participatory Rural Appraisal (PRA) tools were used to source information. A total of 600 questionnaires were administered in 10 villages. The results showed no significant contribution of MCNP activities to livelihood of the local people. Implemented innovative income programs had not yet attained optimum production level. Household income level was perceived to have increased slightly. Previous income activities that impacted negatively conservation such as small-scale logging and shifting cultivation have been abandoned and replaced mainly by innovative income programs such as agroforestry farming, mixed crop farming and sustainable debarking of Prunus africana. However, the sustainability of the innovative income activities would require a more practical match making approach for management. &nbsp; Key words: Protected areas, management, participatory rural appraisal, household income level.

Environmental impact assessment and statistical analysis of natural radioactivity in the slopes of Mount Cameroon area

Environmental impact assessment and statistical analysis of natural radioactivity in the slopes of Mount Cameroon area

Contribution of advanced edge detection filters for the structural mapping of the Douala Sedimentary Basin along the Gulf of Guinea

The Douala sedimentary basin (DSB) is an area of interest because of its hydrocarbon potential. Geophysical investigations in this basin are necessary to understand its structural features better. In this study, we aimed to highlight the major lineaments of the DSB by interpreting gravity data using advanced edge detection filters based on various combinations of the horizontal and vertical gradients of the field, namely the total horizontal gradient (THG), analytical signal (AS), theta map (TM), gradient amplitude of the vertical derivative (THG_VD), the tilt angle of the total horizontal gradient amplitude (TAHG) and a novel edge detector based on the soft sign function (SF). These filters were first tested on synthetic data of a simple density model to examine their effectiveness. The results show that the edges of the model structures can be visualized with greater accuracy using the TAHG and SF filters compared to the results from the others.&#x0D; Further, although the TAHG and SF filters produced good results in identifying shallow and deep structures, solutions from SF proved to be better at delineating edges. Next, we applied these edge detection filters to the residual gravity anomaly of the study area obtained after a filtering process on the complete Bouguer anomaly. The SF filter clearly and accurately identifies the major structural features. The existence and location of previously unidentified lineaments have been shown. Most of the lineaments of the DSB extracted by this study provide geometric information on the lateral distribution of depositional successions filling the basin. The structural features are mainly concentrically from the volcanic center of Mount Cameroon and show that the DSB has probably been affected by earthquakes from the permanent activities of the Cameroon volcanic line since the Cretaceous. The highlighted lineaments of the DSB obtained from this study may shed light on future studies to improve mineral/hydrocarbon exploitation and update the area's geological/tectonic information.

Changes in Bird Community Structure on Mount Cameroon Driven by Elevational and Vertical Gradients

The distribution of birds in the tropical mountains is important not only for testing fundamental scientific hypotheses, but also for bird conservation. In order to obtain knowledge on bird community structure within the tropical highland ecosystem, we used ground-to-canopy mist nets to assess bird species distribution along a vertical ground-to-canopy gradient for two elevational bands on Mount Cameroon. The study area included lowland forest (Drink Garri, 650 m a.s.l.) and montane forest (Mann’s Spring, 2200 m a.s.l.). We mist netted a total of 2658 individuals, including recaptures, belonging to 118 species from 50 genera. NLAG (net location above the ground), vegetation cover and locality significantly affected the bird communities. The composition of avian communities strongly differed between the two elevational bands. Species diversity considerably decreased with NLAG in both localities and increased with increased vegetation cover at the low elevation site. Species dietary guilds were significantly influenced by the seasonality, elevation, NLAG and vegetation cover. For most of the feeding guilds included in the study (frugivores, omnivores, insectivores, granivores and nectarivores), we found a negative correlation between the abundances and vegetation cover. Meanwhile, percentages of abundance of frugivores, nectarivores and omnivores showed a positive correlation with NLAG. We discuss the substantial changes in feeding guild structure along a vertical gradient and between two elevational bands. In conclusion, Mount Cameroon’s forest vegetation structure differs between two elevational bands and along vertical gradients from ground to canopy, considerably affecting the bird community structure.

Assessment and characterization of postharvest handling techniques in the value chain of Malay apple (Syzygium malaccense [L.] Merr. & L.M. Perry) in the Mount Cameroon region

The study examined the problem of excessive postharvest losses (PHLs) of Malay apples due to inadequate postharvest handling, which is hindering the growing demand for the fruit. The study surveyed 160 growers and 40 traders using semi-structured questionnaires to assess postharvest handling practices and propose storage techniques in the Mount Cameroon Region. Data were obtained via face-to-face interviews using semi-structured questionnaires. The data were analysed using descriptive and inferential statistics. Also, the effects of control (no application), hot water dip, 1-MCP, and Aloe vera gel treatments on the quality of Malay apples stored at room temperature for 24 days were examined using a completely randomised design. Chi-square results showed a significant (p< 0.05) association between sociodemographic factors [gender (χ2 = 25.004, p = 0.050), educational level (χ2 = 63.797, p = 0.034), and farming experience (χ2 = 48.87, p = 0.047)] and PHLs. Results showed that inadequate postharvest handling was leading to excessive PHLs, and appropriate postharvest techniques were necessary to maintain the fruit's quality and reduce losses. Significant differences were observed among harvesting, transportation and storage methods, packaging materials, and marketing methods, with harvest and storage showing higher PHLs of 40% and 35%, respectively. The study also found that 1-MCP and Aloe vera were effective in extending the storage life of Malay apples while maintaining quality. The study concluded that growers and traders should adopt proper postharvest techniques in their operations, including handpicking, and application of 1-MCP or Aloe vera gel coating to reduce PHLs and maintain fruit quality for 12 days. Overall, the study highlights the importance of better postharvest handling practices and storage techniques to reduce postharvest losses and improve the supply chain's efficiency. Future research could explore the applicability of these findings on other fruits and geographical locations, and investigate the underlying mechanisms that contribute to the effectiveness of these treatments.

Abundance variations within feeding guilds reveal ecological mechanisms behind avian species richness pattern along the elevational gradient of Mount Cameroon

AbstractTwo distinct diversity patterns are observed along tropical elevations: (a) decreasing number of species toward high elevations and (b) a hump‐shaped pattern with the peak at mid‐elevations. As diversity is likely supported by ecological capacity of the environment, decomposition of the overall richness into ecological facets and considering number of individuals within them is crucial for the proper understanding of richness patterns. We examined abundances of different avian guilds along the forested part of the elevational gradient on Mt. Cameroon. We (a) compared richness and abundance elevational patterns, (b) assessed the effective contribution of multiple guilds to richness and abundance patterns, and (c) assessed to what extent observed abundances of guilds differed from those expected by chance. We sampled birds in 2011–2015 during the dry season at seven elevations (30 m, 350 m, 650 m, 1100 m, 1500 m, 1850 m, 2200 m a.s.l.). For each assemblage, we estimated proportions of species and individuals that use particular diets, foraging modes, and feeding strata. We found that a rather decreasing pattern of species richness turns into a hump‐shaped one if we look at the total abundances, implying different mechanisms behind these patterns. The number of species and individuals thus do not seem to be directly related, contrary to “the more‐individuals hypothesis.” Abundances of foliage gleaners at mid‐elevations, nectarivores at high elevations, and frugivores at low elevations deviated from random expectations. Our results imply that parts of ecological space are filled separately by bird species and individuals along elevation of Mt. Cameroon.

Sub-microscopic Plasmodium falciparum parasitaemia, dihydropteroate synthase (dhps) resistance mutations to sulfadoxine–pyrimethamine, transmission intensity and risk of malaria infection in pregnancy in Mount Cameroon Region

BackgroundPlasmodium falciparum resistance to intermittent preventive treatment with sulfadoxine-pyrimethamine (IPTp-SP) continues to spread throughout sub-Saharan Africa. This study assessed the occurrence of microscopic and sub-microscopic P. falciparum parasitaemia, dihydropteroate synthase mutations associated with resistance to SP and maternal anaemia in the Mount Cameroon area.MethodsConsenting pregnant women living in semi-rural and semi-urban/urbanized settings were enrolled in this cross-sectional study. Socio-demographic, antenatal and clinical data were documented. Microscopic and sub-microscopic parasitaemia were diagnosed using peripheral blood microscopy and nested polymerase chain reaction (PCR) respectively. The dhps mutations were genotyped by restriction fragment length polymorphism analysis. The presence of A437G, K540E, and A581G was considered a marker for high-level resistance. Haemoglobin levels and anaemia status were determined.ResultsAmong the women, the prevalence of microscopic and sub-microscopic P. falciparum infection were 7.7% (67/874) and 18.6% (93/500) respectively. Predictors of microscopic infection were younger age (< 21 years) (AOR = 2.89; 95% CI 1.29–6.46) and semi-rural settings (AOR = 2.27; 95% CI 1.31–3.96). Determinants of sub-microscopic infection were the rainy season (AOR, 3.01; 95% CI 1.77–5.13), primigravidity (AOR = 0.45; 95% CI 0.21–0.94) and regular ITN usage (AOR = 0.49; 95% CI 0.27–0.90). Of the145 P. falciparum isolates genotyped, 66.9% (97) carried mutations associated with resistance to SP; 33.8% (49), 0%, 52.4% (76) and 19.3% (28) for A437G, K540E, A581G and A437G + A581G respectively. The A581G mutation was associated with ≥ 3 SP doses evident only among sub-microscopic parasitaemia (P = 0.027) and multigravidae (P = 0.009). Women with microscopic infection were more likely from semi-rural settings (AOR = 7.09; 95% CI 2.59–19.42), to report history of fever (AOR = 2.6; 95% CI 1.07–6.31), to harbour parasites with double resistant mutations (AOR = 6.65; 95% CI 1.85–23.96) and were less likely to have received 2 SP doses (AOR = 0.29; 95% CI 1.07–6.31). Microscopic infection decreased Hb levels more than sub-microscopic infection.ConclusionThe occurrence of sub-microscopic P. falciparum parasites resistant to SP and intense malaria transmission poses persistent risk of malaria infection during pregnancy in the area. ITN usage and monitoring spread of resistance are critical.

Occurrence and nutrient retention of aquatic macrophytes in roadside streams in the Mount Cameroon region

Roadside streams in the Mount Cameroon region are predisposed to nutrient enrichment from different anthropogenic activities carried out around catchment areas. The composition and diversity of aquatic macrophytes in three roadside streams in the MCR, the biomass, and nutrient accumulation of the most abundant aquatic macrophytes in one of the streams were assessed in order to better understand and quantify the benefits accruing from these macrophytes. Vegetation sampling was carried out along the transects at 50 m intervals, within which plots were laid. Quadrats of 1m by 1m were sub-sampled within each plot and all plants were identified and enumerated. Water, sediment, and plant samples were collected and analysed for nutrients using standard procedures (nitrogen and phosphorus). The results show that the aquatic vegetation of the roadside streams is limited to emergent (&gt; 98%) and floating-leaved life forms. A total of 47 aquatic macrophytes from 18 plant families were identified from the 3 studied wetlands in the Mount Cameroon region. Plant taxa with many representative species included Poaceae (8 species), Araceae (6), Acanthaceae (5), and Asteraceae (4). A high Shannon-Wiener diversity was recorded across study sites (H ≥ 2.9) with the highest in Ombe and the least in Bota. P. purpureum showed significantly higher biomass (p &lt; 0.05) compared to the other macrophytes. It had the highest fresh weight and dry weights (FW: 12.8±1.45 kg/m2 and DW: 0.81± 0.11kg/m2) relative to C. benghalensis and I. aquatica.TN content was highest in C. benghalensis (12.92 ± 0.67 g/kg). P. pupureum and I. aquatica didn’t differ significantly in their nitrogen content (P≤ 0.05) while all three species contained high phosphorus concentrations in their above-ground tissues. TP storage was in the order C. benghalensis &gt;P. purpureum&gt;I. aquatica. This suggests that aquatic macrophytes play vital roles in retaining phosphorus and nitrogen hence affecting water quality and nutrient dynamics of these streams. These nutrient-rich plants can be removed from the aquatic system by harvesting and used as fodder to prevent nutrient release into the water column through decomposition after plant dieback.

Occurrence and nutrient retention of aquatic macrophytes in roadside streams in the Mount Cameroon region

Occurrence and nutrient retention of aquatic macrophytes in roadside streams in the Mount Cameroon region

Characteristics of the Mount Cameroon seismicity for the 2005–2015 period (Cameroon, West-Central Africa)

Characteristics of the Mount Cameroon seismicity for the 2005–2015 period (Cameroon, West-Central Africa)

Ecological niches of epiphyllous bryophytes along Afrotropical elevation gradient

Understanding multiple environmental drivers governing tropical organisms' distribution and ecological niches is crucial for predicting their responses to ongoing rapid deforestation. While macroclimatic effects via energy and water availability are well predicted, less is known about locally modulating factors such as canopy structure, light and edaphic conditions. Here we show that minimum temperatures and ambient humidity drive the abundance and richness of leaf‐inhabiting epiphyllous bryophytes across 4‐km elevation gradient on Mount Cameroon, West Africa, separating epiphyll‐rich rainforests (0–2200 m a.s.l.) from epihyll‐poor fire‐driven afromontane savanna (2300–4000 m a.s.l.). However, local factors contribute more than half to the total abundance and richness variation, either directly (light) or indirectly (edaphic conditions) via their effects on host plant composition. The most abundant epiphyllous communities occur in vertically stratified upland rainforests between 600 and 1100 m elevation, where N‐fixing tree legumes dominate. Their canopy is relatively sparse, due to nutrient‐poor soils leached by high rainfall, leaving room for the development of diverse subcanopy tree and understory shrub and herb layers with epiphyll‐rich communities. Vertically homogenous lowland rainforests on fertile soils below 500 m, with dense overstory and shaded and species‐poor understory, have less developed epiphylls, as do seasonally dry montane forests between 2000 and 2300 m, or elephant fragmented forests between 1200 and 1600 m. We conclude that high temperature and humidity together with a vertically stratified canopy support epiphylls, whereas precipitation seasonality, disturbed vegetation with unstable microclimate, or dense, unstratified canopy discourage the development of epiphyllous communities. Our study illustrates that ecological niches of epiphyllous bryophytes are shaped by a complex interplay of multiple drivers, knowledge of which is essential for more realistic predictions of the impacts of current accelerated habitat loss on species distribution and diversity changes in the tropics.

Impact of altitude on spring macroinvertebrates and water quality in South West region of Cameroon

We evaluated the impact of altitude on the biodiversity and water quality of 13 springs located from 82 to 1,189 m a.s.l. on Mount Cameroon. The springs were of good chemical and ecological quality whatever the altitude. The analysis of the physicochemical variables showed low temperature levels (19.50 ± 2.09 °C), high turbidity (13.0 ± 7.17 FTU), and an acceptable mineralization level (324.95 ± 260.0 μS/cm), with high amounts of phosphate nutrients (0.83 ± 0.47 mg/L). We observed a strong seasonal effect, with a decrease in temperature and nutrient content during the dry season whereas pH and dissolved oxygen increased. A total of 10,265 organisms, distributed into 56 families, were collected. They mostly included insects (47.8%), closely followed by Arachnida (34.8%). Only two stygobite taxa were recorded, namely Darwinulidae and Stenasellidae. Total diversity slightly decreased with altitude, especially during the dry season. Despite lower temperature and more oxygen at higher altitudes, diversity, including EPT did not increase. Therefore, African fauna are less sensitive to rising temperature than the faunas of other areas of the world. This result may be explained either by the fact that African species are better adapted to warm, low-oxygen waters than species from other parts of the world, or by the absence of refuges in Mount Cameroon that are home to temperature-sensitive species. Consequently, the impact of climate change on aquatic macroinvertebrates in tropical Africa could be reduced.