Submontane Forest Research Articles

A new cloud forest tree Lychnodiscus bali (Sapindaceae), Critically Endangered from the Bali-Ngemba Forest Reserve, NW Region, Cameroon

SummaryWe describe and illustrate Lychnodiscus bali Cheek (Sapindaceae), a new species to science, from the Bali Ngemba Forest Reserve of NW Region Cameroon, the last major remnant of cloud forest in the Bamenda Highlands of Cameroon, recently evidenced as a Tropical Important Plant Area (TIPA or IPA). Confined on current evidence to upper submontane forest, the new species is threatened by expanding habitat clearance for farms and is assessed as Critically Endangered. A small tree, attaining 3 – 4 m height, it is the first new species to be added to this Guineo-Congolian tree genus in 50 years, the third recorded from Cameroon and takes the number of species in the genus to eight. It has the highest known altitudinal range (1700 – 1950 m alt.) of any species of the genus. We discuss its discovery in the context of other recently discovered and highly threatened or even extinct plant species in the Cameroon Highlands, and the importance of their conservation. The new species was previously identified as Lychnodiscus grandifolius Radlk., but differs in the shorter length of the distal leaflets (12 – 18 cm vs 22 – 39 cm long); in the abaxial leaf surface lacking glands (vs glands flat and conspicuous); in being sparsely hairy all over (vs glabrous except the main veins) and in its larger flowers, 8 – 11 mm long at anthesis (vs 5 – 7 mm long). We present an identification key of the species of Lychnodiscus and discuss their classification in the context of recent molecular phylogenetic and phylogenomic studies. The authors contend that Lychnodiscus Radlk., previously placed in Cupanieae by Radlkofer, should now be placed in the reconstituted Nephelieae in the revised 2021 intrafamilial classification of Buerki et al., probably close to the genera Aporrhiza Radlk. and Laccodiscus Radlk. However, until the genus is included in molecular studies this cannot be confirmed and a sister relationship remains speculative.

Elevational shifts in tree community composition in the Brazilian Atlantic Forest related to climate change

AbstractQuestionClimate change induces shifts in species distributions, ultimately changing community composition. Mountains are especially sensitive to climate change, and tree species are predicted to move towards higher elevations, but observed changes are not always unidirectional. The diversity and complexity of tropical and subtropical systems limits our understanding of climate‐induced responses of subtropical mountain forests. Here, we investigated migration trends in tree community composition along an elevational gradient, and between the transition from lowland to montane forests in subtropical forests.LocationBrazilian Atlantic Forest.MethodsWe used thermal affiliations of 627 tree species to calculate community temperature scores (CTS) for different life‐history stages of trees in 96 permanent plots. We compared CTS of different life‐history stages across space and time.ResultsMost tree communities (58%) did not show a significant difference of CTS between life‐history stages, indicating a non‐migration trend. On the other hand, 27% of tree communities showed upward migration and 15% downward migration. Upward migration was more common in montane forests, and downward migration in lowland forests. Our temporal analysis shows significant changes in CTS values for juvenile communities with 0.36°C decrease in lowland forests and 0.34°C increase in montane forests.ConclusionsContrasting results between lowland and montane forest communities indicate that the transition zone influences migration patterns and may reflect differences in species’ thermal limitations, as well as by non‐thermal factors such as biotic interactions. Our findings provide the first evidence of climate change‐induced community shifts in the Brazilian Atlantic Forest. We demonstrated that upward migration trends were predominantly observed in montane–upper mountain forests, while downward migrations were noted in lowland–submontane forests. The thermophilization of montane forests may suggest an increased risk of reduction for cold‐demanding species under climate change scenarios.

Variation in fern species richness, assemblages and morphology along a tropical riparian humidity gradient: an example from Borneo

ABSTRACT Riparian vegetation experiences a little spatial distance humidity gradient, especially in the hyper-humid tropics. In Borneo, with almost no seasons and rather constant local climatic conditions, the riparian plant species show a wide range of morphological and physiological adaptations. This study assesses the adaptation strategies of ferns along a riparian humidity gradient in the submontane forest of Sarawak, Malaysia (Borneo). The species richness and cover, morphological traits, leaf area, leaf perimeter, leaf dissection, leaf elongation ratio, and stomatal density of 63 fern species were surveyed in six study areas along six stream transects. Significant trends in species richness and species cover were identified along the six transects, and changes in morphological traits such as leaf area, leaf perimeter, and leaf dissection were also discovered. With increasing distance from the streams (i.e. decreasing humidity), ferns tended to show longer leaves and a lower stomatal density. We conclude that the morphological traits of fronds change significantly within a short tropical riparian humidity gradient. This reveals variations in the energy investment and adaptation efficiency of ferns within a tropical forest microsite.

Food resource partitioning between males and females of Volcano Sunbird (Cinnyris preussi) on Mount Cameroon

Competition for nectar is expected to result in feeding niche differentiation. Here, we targeted the sexually size-dimorphic Volcano Sunbird (Cinnyris preussi) on Mount Cameroon. We investigated whether males and females feed on different plant species, whether females with shorter bills than males prefer shorter flowers, and whether larger dominant males visit more energetic flowers that produce higher amounts of nectar sugars. We also asked whether feeding niches were spatially separated along the elevation gradient and whether this separation varied between the two contrasting seasons. We collected data on the frequency of visits to individual plant species and analyzed the male-to-female ratios in the mist-netted dataset. In addition, we estimated production of nectar sugar in individual habitats and seasons. Despite the large dataset collected, encompassing 6476 bird–plant interactions, our findings did not provide evidence of differences in the spectra of the visited plant species. In addition, females did not visit flowers with shorter tubes, nor did males visit flowers that produced higher amounts of sugars. However, we observed a sex-specific dispersion of sunbirds during the wet season. During the dry breeding season, both males and females feed mainly in nectar-rich montane and submontane forests. In the wet season, the production of nectar sugar in these habitats decreased dramatically, and females largely disappeared. In contrast, female activity increased in the lowest and highest parts of the altitudinal range. Our findings on elevational movements are important in the current context, in which species face potential threats from habitat destruction and climate change.

Allometric models for estimating above- and below ground biomass of individual trees in Cameroonian submontane forest

This study is the first to develop allometric models for estimating above-ground biomass (AGB) and below-ground biomass (BGB) of individual trees based on destructive sampling procedures in the montane tropical forests of Central Africa. As Cameroon is committed to Reducing Emissions from Deforestation and Forest Degradation (REDD) initiatives, it is particularly important for the country to develop such models. The data used for the modeling covered a wide range of tree species (34) and diameters at breast height (dbh) from 6 to 117 cm. The AGB and BGB models were developed from 60 and 30 tree samples, respectively. The developed AGB models explained a large part of the biomass variation (Pseudo-R2 0.80-0.87) and performed well when tested over different size classes. A model with dbh, basic wood density and total tree height (h) as independent variables is generally recommended for application if appropriate information on h is available. Tests of previously developed AGB models with modeling data, where large mean prediction errors occurred, generally demonstrated the importance of developing local models. BGB models performed reasonably well over different size classes, and biomass per unit area will probably be appropriately estimated when applying them. Some of the challenges related to the estimation BGB for small trees mean, however, imply that, the models may need to be recalibrated if more data becomes available.

Keita (Aptandraceae-Olacaceae s.l.), a new genus for African species previously ascribed to Anacolosa, including K. deniseae sp. nov., an Endangered submontane forest liana from Simandou, Republic of Guinea

SummaryWe show that the two continental African species previously ascribed to the genus Anacolosa, differ in so many architectural, floral and vegetative characters from the remaining species of the genus (which occur from Madagascar to the western Pacific, including the type) that they clearly represent a separate genus. The African genus represented by these two species is unique within the Olacaceae s.l. (excluding Erythropalaceae) in being a climber (vs shrubs or trees in Anacolosa sensu stricto). Climbing in the two African species is achieved by perennial hook-like structures formed by a combination of five separate traits each of which is unknown elsewhere in the Olacaceae s.l. We formally delimit, describe and name this new African genus as Keita. Placement is tentatively in Aptandraceae but confirmation by molecular studies is required. We describe a new species from Guinea as Keita deniseae sp. nov. and transfer the Central African (Democratic Republic of Congo (DRC), Republic of Congo & Gabon) species from Anacolosa to the new genus as Keita uncifera comb. nov. Keita deniseae is assessed using the IUCN (2012) criteria as Endangered due to the threat of clearance or degradation of forest habitat for mining and agriculture, while K. uncifera is assessed as Least Concern in view of its large range, number of locations and low levels of threat. We review the discovery of Keita deniseae in the light of other recent discoveries of new taxa in both Simandou and the Republic of Guinea.

Estimation of ammonia deposition to forest ecosystems in Scotland and Sri Lanka using wind-controlled NH3 enhancement experiments

Ammonia (NH3) pollution has emerged as a major cause of concern as atmospheric concentrations continue to increase globally. Environmentally damaging NH3 levels are expected to severely affect sensitive and economically important organisms, but evidence is lacking in many parts of the world. We describe the design and operation of a wind-controlled NH3 enhancement system to assess effects on forests in two contrasting climates. We established structurally identical NH3 enhancement systems in a temperate birch woodland in the UK and a tropical sub-montane forest in central Sri Lanka, both simulating real-world NH3 pollution conditions. Vertical and horizontal NH3 concentrations were monitored at two different time scales to understand NH3 transport within the forest canopies. We applied a bi-directional resistance model with four canopy layers to calculate net deposition fluxes. At both sites, NH3 concentrations and deposition were found to decrease exponentially with distance away from the source, consistent with expectations. Conversely, we found differences in vertical mixing of NH3 between the two experiments, with more vertically uniform NH3 concentrations in the dense and multi-layered sub-montane forest canopy in Sri Lanka. Monthly NH3 concentrations downwind of the source ranged from 3 to 29 μg m−3 at the UK site and 2–47 μg m−3 at the Sri Lankan site, compared with background values of 0.63 and 0.35 μg m−3, respectively. The total calculated NH3 dry deposition flux to all the canopy layers along the NH3 transects ranged from 12 to 162 kg N ha−1 yr−1 in the UK and 16–426 kg N ha−1 yr−1 in Sri Lanka, representative of conditions in the vicinity of a range of common NH3 sources. This multi-layer model is applicable for identifying the fate of NH3 in forest ecosystems where the gas enters the canopy laterally through the trunk space and exposes the understorey to high NH3 levels. In both study sites, we found that cuticular deposition was the dominant flux in the vegetation layers, with a smaller contribution from stomatal uptake. The new facilities are now allowing the first ever field comparison of NH3 impacts on forest ecosystems, with special focus on lichen bio-indicators, which will provide vital evidence to inform NH3 critical levels and associated nitrogen policy development in South Asia.

A new insular species of Begonia (Begoniaceae) from São Paulo State, Brazil

Begonia schizostya, a new species of Begonia sect. Astrothrix from São Paulo state, Brazil is described. Begonia schizostyla is morphologically similar to Begonia bullatifolia and Begonia crispula, with which it is compared. The new species grows in Ombrophilous Dense Submontane Forest, over rocks inside the primary forest of São Sebastião Island. Description, comparisons with related species, etymology, taxonomic comments, illustration and localization map of the new species are provided.

Ecological Correlates for Endemic and Threatened Amphibians in the Uluguru Nature Forest Reserve, Tanzania

Information on habitat characteristics for endemic and threatened amphibians along the altitudinal gradient in the Uluguru Nature Forest Reserve (UNFR) is limited. We assessed habitat characteristics associated with the occurrence of endemic and threatened amphibians in the Uluguru Nature Forest Reserve between April and June 2022. Bucket pitfall traps, time-constrained audio-visual surveys, plots and opportunistic searching were used to study amphibians in 6 sites along elevational gradient from 600 m to 2100 m a.s.l. Eighteen amphibian species were recorded, thirteen of them being endemic to the Eastern Arc Mountains, two near-endemic and three widely distributed. Among the species recorded, seven are categorized as threatened as per IUCN Red List. We observed more endemic and threatened amphibians in the submontane forests (1200–1800 m) than in other sites. Negative correlations existed between temperature, canopy cover, leaf litter cover and leaf litter depth and species richness, whereas positive correlations existed between humidity and species richness. No single factor was responsible for the occurrence of endemic and threatened amphibians in the Uluguru Nature Forest Reserve. This is only a snapshot survey on the occurrence of threatened and endemic amphibians and their associated habitat features in the northern part of the Uluguru Nature Forest Reserve. A long-term monitoring of these amphibian species is recommended especially at this era of unprecedented forest loss and degradation.

Classification of forest and shrubland vegetation in central and eastern Euxine Turkey and SW Georgia

AbstractQuestionsWhat are the main vegetation types of forest and shrubland vegetation in central and eastern Euxine Turkey and SW Georgia? What are the main environmental factors affecting their diversity? What is their syntaxonomic position? Can we integrate them into the European vegetation classification system?LocationCentral and eastern Euxine Turkey and SW Georgia.MethodsWe collected 3104 vegetation plots of forest and shrubland vegetation in the study region and performed Two‐Way Indicator Species Analysis (TWINSPAN) classification. We described vegetation types based on the classification results, expert knowledge and information from literature sources. We defined diagnostic species and prepared distribution maps for each vegetation type. To determine the most significant environmental variables on floristic differentiation, we used canonical correspondence analysis. Detrended correspondence analysis with passive projection of most significant environmental variables was run to interpret the environmental variation of vegetation types.ResultsThe studied vegetation was divided into 29 vegetation types related to seven main vegetation groups: relict Mediterranean forests and shrubland (mainly along the coastline, beside some inland localities), lowland to submontane forests, central Euxine mountain forests, eastern Euxine (Colchic) mountain forests, subeuxine forests, azonal riparian forests and subalpine and alpine shrubland. Elevation is the most important factor causing the differentiation in vegetation. It is followed by longitude and latitude. Among climatic variables, temperature seasonality, annual precipitation and precipitation of the wettest quarter are the most significant factors for vegetation differentiation. These factors correlate with the reduction of maritime climate and geomorphological features.ConclusionsVegetation types mostly correspond to the syntaxa accepted in the EuroVegChecklist. However, some of them do not appear in the EuroVegChecklist since they appear only beyond Europe. We described three syntaxa as new: Abietion equi‐trojani, Querco cerridis‐Carpinion orientalis and Piceo orientalis‐Fagenion orientalis. The study revealed high vegetation diversity of the region that should be taken into consideration in ecosystem management and used as a reference in restoration and mitigation of the effects of global changes.

Trichoglottis quadriga (Orchidaceae: Epidendroideae: Vandeae: Aeridinae), a new species from Central Highlands of Sri Lanka

Trichoglottis quadriga is described as a new species from the montane and sub-montane forests, between 900–1800 m elevations in Central Highlands of Sri Lanka. It is morphologically similar to Vietnamese endemic, T. canhii, but differs significantly in having 4-flowered racemes (vs. 5–12-flowered racemes); longer, terete spur, 3.2 mm long and 1.2 mm in diameter with bi-lobed apex (vs. shorter, broadly conical spur, 1.4–1.8 mm long and 1.2–1.5 mm in diameter near the base with roundish apex) and larger labellum, 5.5 mm long and 3.5 mm wide (vs. labellum 3.8–4.0 mm long, 1.8–2.0 mm wide). Colour plates, line drawing and field identification key are provided along with detailed taxonomic description, notes on habitat, ecology and distribution. A preliminary assessment of extinction risk according to the IUCN guidelines is also provided for the new species.

Mapping spatial microclimate patterns in mountain forests from LiDAR

Forests create unique microclimates that have the potential to serve as microrefugia for species under climate change. Yet, our understanding of the heterogenous thermal patterns at the forest floor of complex landscapes (e.g., in mountain forests) remains incomplete. We here used Light Detection and Ranging (LiDAR) for predicting summer temperature offsets in a mountain forest landscape in the European Alps. We calibrated models on a network of 150 microclimate loggers that were combined with data from 15 meteorological stations to estimate the maximum, mean, and minimum temperature offsets, using LiDAR-derived metrics of forest structure and topography as predictors. Models predicted summer temperature offsets with an R²/RMSE of 0.50/3.15 °C for maximum temperature, 0.51/0.41 °C for mean temperature and 0.55/0.57 °C for minimum temperature. Forest canopy openness and elevation were most important for predicting temperature offsets. The mean offset ranged from – 1.9 °C to 2.7 °C (mean of - 0.3 °C), but both minimum and maximum offsets varied considerably, with some forests even having warmer maximum and colder minimum temperatures than open areas. This was particularly prominent in forests of the subalpine zone, which are characterized by open canopies and a considerable presence of coniferous shrubs. In contrast, submontane forests with largely closed canopies had mostly colder maximum and warmer minimum temperatures within forests compared to open areas. Analysing the development of temperature offsets with time since disturbance, we found that recently disturbed forests had higher maximum temperatures compared to open areas, but they recovered to closed forest conditions within two decades. We conclude that mountain forests exhibit complex microclimate patterns that vary strongly with forest type and canopy openness. We further highlight that disturbances are an important driver of spatiotemporal dynamics in forest microclimate. Finally, temperature offset maps such as the ones generated here have strong potential to improve the robustness of species distribution models and to assess climate risks for biodiversity.

Predicting suitable habitat for the endangered Javan Gibbon in a submontane forest in Indonesia

Species distribution modeling is an essential tool for understanding the ecology of species and has many applications in conservation. Using maximum entropy (MaxEnt) modeling, we identify the key factors shaping the potential distribution of the endangered Javan Gibbons Hylobates moloch in one of the main remnant habitats, Gunung Halimun Salak National Park (GHSNP), Indonesia, using presence-only data collected between October and November 2015, and in April and May 2016. Maxent results showed that forest canopy density and annual temperature were the principal variables predicting the distribution of Javan Gibbons, with contribution scores of 53.9% and 35.6%, respectively. The predictive distribution map indicated that suitable habitat for Javan Gibbons is not uniformly distributed within GHSNP, i.e., suitable habitat is not located evenly throughout the region, with some areas more suitable than others. Highly suitable habitat comprises the largest proportion of habitat, with 42.1% of GHSNP classified as highly suitable habitat, whereas 24.7% was moderately suitable, and 33.2% of habitat was of low suitability for Javan Gibbons. Priority should be given to increasing habitat quality in degraded areas and law enforcement patrols to reduce degradation in peripheral regions of the park as part of the conservation management strategy.

VARIATION IN THE COMPOSITION AND STRUCTURE OF NATURAL LOWLAND FORESTS AT BODOGOL, GUNUNG GEDE PANGRANGO NATIONAL PARK, WEST JAVA, INDONESIA

An analysis of the composition and structure of lowland natural forests was carried out in Bodogol, Gunung Gede Pangrango National Park (GGPNP). The two study plots (P1CS and P2CS) were located on Cisuren and one plot (P3CP) on Cipadaranten hill. We recorded 107 species and 48 families with an average basal area of 19.73 m2/ha, and an average density of 348 trees/ha. The species richness was poorer than those of the typical lowland rainforests of Kalimantan and Sumatra but comparable to those of the montane forests of Java. The IUCN-Red Listed species were Castanopsis argentea and Castanopsis tungurrut (critical) and Saurauia bracteosa (vulnerable). Based on the two dominant species, the forests can be designated as the Maesopsis eminii-Syzygium acuminatissimum association and Syzygium acuminatissimum-Lithocarpus korthalsii association. Maesopsis eminii was dominant in P1CS (IV= 56.46%) and P3CP (IV=55.94%), while Syzygium acuminatissimum in P2CS (IV= 43.67%). Maesopsis eminii was a strongly aggressive and invasive species, that endangered the purity of the natural forest GGPNP, therefore, it must be eradicated. Vertically, P2CS and P3CP consisted of four strata, while P1CS had three strata. This one-hectare study can be considered as a minimal area to reflect the floristic representation of lowland forest and submontane forest.

A massive Critically Endangered cloud forest tree, Microcos rumpi (Grewiaceae) new to science from the Rumpi Hills, SW Region, Cameroon

SummaryWe describe Microcos rumpi (Grewiaceae) a massive new species to science from the Rumpi Hills of SW Region Cameroon, a proposed Tropical Important Plant Area. Confined on current evidence to submontane forest, the species is threatened by expanding habitat clearance for farms and is assessed as Critically Endangered. A large tree, attaining 35 – 40 m height, and 80 cm trunk diam. at 1.3 m above ground, its biomass is calculated as in the range of 7 – 8 metric tonnes. It is the third tree species of the genus recorded from Cameroon and only the fourth recorded west of D.R. Congo. A key to these four species is presented.The concept of Microcos in Africa in relation to Grewia is discussed, and three new combinations are made, transferring three species names from Grewia to Microcos: Microcos louisii (R.Wilczek) Cheek, M. evrardii (R.Wilczek) Cheek and M. schmitzii (R.Wilczek) Cheek.

The Habitat Analysis of Sunda Clouded Leopard (Neofelis diardi Cuvier 1823) in Batutegi Protection Forest Lampung

Sunda clouded leopard (Neofelis diardi Cuvier, 1823) is a predator that threatened by habitat fragmentation due to the conversion of forest into residential and agricultural areas. One of the habitats of sunda clouded leopard in Sumatra is in the Batutegi Protection Forest. This research aimed to identify the habitat functions of sunda clouded leopard and its characteristic. Data were collected by direct observation using vegetation plots, line transect, camera trapping, and indirect observation to determine signs of animal activities. Vegetation and canopy openness analysis was used to describe the habitat characteristic, while data of potential prey were analyzed using species diversity and abundance indices. The results show that hunting area for sunda clouded leopard was an area with dense canopy cover (64,67%). Resting area and cover area for sunda clouded leopard were areas with very dense canopy cover (78,64% and 73,43%). Potential prey diversity and abundance with higher rate found in lowland forest (H’=2,35), while the lower rate found in sub-montane forest (H’=1,81).

Tree species composition along environmental and disturbance gradients in tropical sub-montane forests, Tanzania.

Understanding the environmental and disturbance determinants of tree species dominance and community composition in an ecosystem, is important for informing management and conservation decisions, through maintaining or improving the existing forest composition and structure. This study was carried out to quantify the relationship between forest tree composition structure and environmental and disturbance gradients, in a tropical sub-montane forest of Eastern Usambara. Vegetation, environmental, and anthropogenic disturbance data for 58 plots across Amani and Nilo nature forest reserves were obtained. Agglomerative hierarchical cluster analysis and canonical correspondence analysis (CCA) were used to identify plant communities and analyze the influence of environmental variables and anthropogenic disturbances on tree species and community composition respectively. Four communities were identified and CCA results showed that the variation was significantly related to elevation, pH, Annual mean temperature, temperature seasonality, phosphorus nutrients and pressures from adjacent villages and roads. Likewise, environmental factors (climate, soil and topography) explained the most variation (14.5%) of tree and community composition in relation to disturbance pressure (2.5%). The large and significant variation in tree species and community patterns explained by environmental factors suggests a need for site-specific assessment of environmental properties for biodiversity conservation plans. Similarly, the intensification of human activities and associated impacts on natural environment should be minimized to maintain forest species composition patterns and communities. The findings are useful in guiding in policy interventions that focus on minimizing human disturbances in the forests and could aid in preserving and restoring the functional organization and tree species composition of the sub-tropical montane forests.

Diversification of spiny-throated reed frogs (Anura: Hyperoliidae) with the description of a new, range-restricted species from the Ukaguru Mountains, Tanzania.

The spiny-throated reed frog species group is a small radiation of Hyperolius frogs from East Africa. Unlike many members of the genus which have relatively wide distributions, these species tend to be small-range endemics found in montane and submontane forests. Recent discovery of a golden-hued frog with the clade-specific traits of spines on their gular discs prompted a morphological and genetic exploration of the distinctness of this new lineage and relationships to other members of the clade. Genetic (mitochondrial and nuclear loci) results resolved many sister-relationships, but deeper nodes in the phylogeny were poorly resolved. A reduced-representation genome-wide Single Nucleotide Polymorphism (SNP) dataset was able to fully resolve the phylogenetic relationships within this clade, placing this new lineage, here named after the mountain range in which is it found-H. ukaguruensis sp. nov., as an early diverging lineage within the group. This new species is distinct from all other spiny-throated reed frogs, necessitating further understanding as a single-mountain endemics vulnerable to habitat loss and potential decline. Morphometric analyses identify clear morphological characteristics that are distinct for the herein described species, most noticeably in that the eyes are significantly smaller than other members of the genus for which we have samples.

Floristic diversity, composition and dominance across Amazonian forest types respond differently to latitude

AbstractAimThe latitudinal biodiversity gradient is considered a first‐order biogeographical pattern for most taxonomic groups. Latitudinal variation in plant diversity is not always consistent, and this could be related to the particular characteristics of different forest types. In this study, we compare latitudinal changes in floristic diversity (alpha diversity), composition (beta diversity) and dominance across different tropical forest types: floodplain, terra firme and submontane forests.LocationWestern Amazonia (Ecuador, Peru and Bolivia).TaxonWoody plants.MethodsWe inventoried 1978 species and 31,203 individuals of vascular plants with a diameter at breast height ≥ 2.5 cm in 118 0.1‐ha plots over an 1800 km latitudinal gradient in three different forest types. The relationships between alpha diversity, latitude and forest type were analysed using generalised linear mixed models. Semi‐parametric permutational multivariate analysis of variance was used to investigate the effects of latitude and forest type on beta diversity. Dominant species abundances were correlated with non‐metric multidimensional scaling ordination axes to reflect their contributions in shaping changes in beta diversity.ResultsAlpha diversity increased towards equatorial latitudes in terra firme and submontane forests but remained relatively constant in floodplains. Beta diversity of all forest types changed with latitude, although less clearly in floodplains. Also, in floodplain forests, there were fewer dominant species contributing to beta diversity and more species homogeneous along the gradient.Main ConclusionsLatitudinal diversity patterns are manifested in alpha and beta diversity since latitude summarizes climatic and edaphic changes. However, we found different responses of each forest type. In floodplain forests, inundation regime is a stronger predictor than latitude, limiting floristic diversity and composition. Changes in dominant species abundance over gradients explained species composition, but floodplain forests harboured more homogeneous dominant species than well drained forests. It is key to study environmental trends and habitat characteristics of each forest type to understand their species diversity and dominance patterns.

Duguetia leucotricha (Annonaceae), a new species from the Atlantic Coastal Forest of Brazil

A new species of Annonaceae, Duguetia leucotricha M.L.Bazante & Maas, from lowland to submontane forests of southern Bahia, Brazil, is described. It differs from other species of the genus mainly by the dense greyish white stellate hairs on vegetative and reproductive structures, rather widely-spaced flowers, the large bract in the upper part of the well-developed pedicel, sepals and petals almost equal in length, and the few-carpellate fruits with rounded apex of the areoles. Commentaries concerning its morphological aspects and relationships of affinity, geographic distribution, conservation status and photos are provided, as well as a key to all Atlantic Coastal Forest species of Duguetia.