Forest Species Diversity Research Articles

Forest Structure and Tree Species Diversity of the Abasumba Globally Significant Biodiversity Area, Ghana

We studied the forest structure and tree species diversity with diameter-at-breast-height (dbh) ≥ 10 cm in the Abasumba Globally Significant Biodiversity Area Ghana. Sixteen 25 m * 25 m plots were demarcated and trees with dbh ≥ 10 cm were inventoried following International Plant Nomenclature Index. The characteristic three–storey structure of tropical forests was shown, 68.7% of trees were in the lower 4.5–18 m and middle 18–30 m storeys. A majority 91.4% of 342 trees was in the dbh of 10–30 cm and a least 8.6% of 32 trees in 31–60 cm had dbh ˃ 60 cm. Total of 46 species, 38 genera and 17 families, with mean Alpha, Shannon and Simpson’s Diversity indices of 13.9, 1.44 and 0.07 and importance value index of 300.0 for 374 trees ha-1 was recorded. Plant families Sterculiaceae, Meliaceae, Leguminosae, Ulmaceae and Bombacaceae was the majority encountered while Triplochiton scleroxylon, Cola millenii, Trichilia monadelpha, Hymenostegia afzelii, Celtis mildbraedii, Ceiba pentandra and Ficus sur was the most occurring species in 54.0% of the plots accounting for 52.0% of the IVI for all trees. Blighia sapida, Bridelia grandis, Dialium guineense, Draceana arborea, Ficus sur, Holarrhena floribunda, Holoptelea grandis, Margaritaria discoidea, Rauvolfia vomitoria, Trilepisium madagascariense, Vitex ferruginea, Ximenia americana and Xylia evansii had one individual in the 10,000 m2 area indicated that they are rare and should be given conservation priority in the forest reserve.

Monoculture plantations impede forest recovery: Evidence from the regeneration of lowland subtropical forest in Hong Kong

Anthropogenic disturbance has led to widespread clearance and degradation of tropical forests, and tree planting has been promoted as an effective solution for recovery. However, trees have been overwhelmingly planted in monocultures or low-diversity mixes and this is expected to have profound, lasting impacts on forest structure, diversity, and functioning. In this study, we tested the extent to which historical vegetation transition types (VTTs) constrain forest recovery in a secondary tropical landscape in Hong Kong, South China. To do so, we overlaid vegetation types (forest, shrubland, pine plantation, grassland) identified in aerial photographs taken in 1956 and 1963 of a 20-ha plot situated in Tai Po Kau Nature Reserve, allowing us to define six historic VTTs, namely: FF (forest to forest), GP (grassland to plantation), GS (grassland to shrubland), SS (shrubland to shrubland), SF (shrubland to forest), and SP (shrubland to plantation). We compared present-day forest structure and species diversity among these VTTs, as determined from a census conducted in 2015, using incidence- and abundance-based rarefaction and extrapolation, and we assessed species’ association within VTTs using a torus translation test. Our results reveal that stem density and species diversity in naturally regenerated forests were more similar to those of old-growth forest, whereas species diversity in areas occupied by pine plantations was significantly lower as compared with naturally regenerated areas. Despite 60 years of recovery, pine plantations were characterised by a significantly greater proportion of negatively associated species, and late-seral species were still predominantly confined to old-growth patches. Present-day species distribution is chiefly explained by the combined effects of topography and VTT (17.1%), with VTT alone explaining 4.4%. Our study demonstrates that VTT has a significant long-term impact on forest regeneration and community assembly and, importantly, that monocultural plantations (forest plantation) can greatly impede forest recovery. Remnant old-growth forest patches merit priority protection, and active restoration, including thinning and enhancement planting, is necessary to facilitate forest succession.

Response of Plant Species Diversity to Flood Irrigation in the Tarim River Basin, Northwest China

This study quantitatively analyzes the effects of flooding on the growth and species diversity of riparian forests along the Yarkant River and the Tarim River, Xinjiang, in northwest China, and provides important information for the efficient utilization of water and water resource management in arid regions. Monitoring of species diversity of riparian forests was conducted every year from 2016 to 2019 in the Xiamale forest district in the lower reaches of the Yarkant River, and in the Shaya forest district and the lunnan forest district in the upper and middle reaches of the Tarim River. The Pielou index, Shannon–Wiener index, Simpson index, and importance value were used to analyze the influence of flooding. The results showed the following: (1) After three years of flooding, indices for the lower reaches of the Yarkant River and Tarim River were significantly increased and 11 new plant species appeared. (2) With increasing distance from the river channel, plant density and species diversity decreased. Flooding trends are the main factors affecting the distribution of plant species and water is the main restricting factor that influences plant growth in arid areas; thus, desert riparian forests improved significantly after flooding. (3) Flooding increases the regeneration capacity and species diversity of plant communities in desert riparian forests. In order to maintain the current trend of ecological improvement, flooding irrigation must continue.

Species diversity pattern and its drivers of the understory herbaceous plants in a Chinese subtropical forest

Understory herbaceous plants are an important component of forest ecosystems, playing important roles in species diversity and forest dynamics in forests. However, the current understanding of the biodiversity of forest communities is mostly from woody plants, and knowledge of community structure and species diversity for understory herbaceous plants remains scarce. In a subtropical forest in China, we investigated understory vascular herbaceous diversity from 300 plots (5 × 5 m) in the main growing season. In this study, we analyzed the community structure and diversity pattern of the understory herbaceous community and linked the species diversity pattern to both abiotic and biotic environments. We found a rich diversity of understory herbaceous communities in this forest (81 species belonging to 55 genera), and floristic elements at the genus level were dominated by tropical elements, followed by temperate elements. The diversity pattern of the understory herbaceous showed a significant habitat preference, with the highest diversity in the lowland valleys and then followed by in middle slopes. In addition, herbaceous diversity was significantly affected by both abiotic factors (such as terrain convexity) and biotic factors (such as the diversity of surrounding woody plants). Our study indicated that species diversity of understory herbaceous showed a remarkable habitat preference, such as lowland valleys, and highlighted the importance of both abiotic and biotic environments in driving herbaceous diversity patterns in the subtropical forest understory.

Quantifying Temperate Forest Diversity by Integrating GEDI LiDAR and Multi-Temporal Sentinel-2 Imagery

Remotely sensed estimates of forest diversity have become increasingly important in assessing anthropogenic and natural disturbances and their effects on biodiversity under limited resources. Whereas field inventories and optical images are generally used to estimate forest diversity, studies that combine vertical structure information and multi-temporal phenological characteristics to accurately quantify diversity in large, heterogeneous forest areas are still lacking. In this study, combined with regression models, three different diversity indices, namely Simpson (λ), Shannon (H′), and Pielou (J′), were applied to characterize forest tree species diversity by using GEDI LiDAR data and Sentinel-2 imagery in temperate natural forest, northeast China. We used Mean Decrease Gini (MDG) and Boosted Regression Tree (BRT) to assess the importance of certain variables including monthly spectral bands, vegetation indices, foliage height diversity (FHD), and plant area index (PAI) of growing season and non-growing seasons (68 variables in total). We produced 12 forest diversity maps on three different diversity indices using four regression algorithms: Support Vector Machines (SVM), Random Forest (RF), K-Nearest Neighbors (KNN), and Lasso Regression (LR). Our study concluded that the most important variables are FHD, NDVI, NDWI, EVI, short-wave infrared (SWIR) and red-edge (RE) bands, especially in the growing season (May and June). In terms of algorithms, the estimation accuracies of the RF (averaged R2 = 0.79) and SVM (averaged R2 = 0.76) models outperformed the other models (R2 of KNN and LR are 0.68 and 0.57, respectively). The study demonstrates the accuracy of GEDI LiDAR data and multi-temporal Sentinel-2 images in estimating forest diversity over large areas, advancing the capacity to monitor and manage forest ecosystems.

Tree community structure, carbon stocks and regeneration status of disturbed lowland tropical rain forests of Assam, India

Tropical rain forests are global hotspots of biodiversity and key climate change regulators. Despite the decades of conservation efforts, tropical forests are increasingly under continuous threat from human activities. Therefore, understanding the impact of anthropogenic disturbances on biodiversity is necessary for better conservation and management. This study focused on a tropical rainforest located in Kakoi reserve, Assam, in the northeastern Himalayas, aiming to compare tree species composition, diversity, carbon stocks, and regenerating status in two forest sites experiencing disturbance regimes. A total of 55 tree species representing 36 genera and 26 families were recorded in the study area. The tree species richness was slightly higher in moderately disturbed (MD) Dirgha than in the highly disturbed (HD) Kakoi-Rajgarh forest. Tree density and basal area were 582 and 446 individuals ha−1, 38.43, and 32.63 m2 ha−1, respectively, in MD-Dirgha and HD-Kakoi-Rajgarh. Forest stand structure followed a typical reverse J-shaped trend in both sites, with a lesser density of large girth-class (>330 cm girth at breast height) individuals in HD-Kakoi-Rajgarh, reflecting the influence of past onsite disturbances. The analysis of the regeneration strata depicted that seedling and sapling density was 1.8 and 1.4 times lower in HD-Kakoi-Rajgarh compared to MD-Dirgha. Above-ground biomass and total carbon stocks were maximum in MD-Dirgha, followed by HD-Kakoi-Rajgarh. About 63.64% of the recorded tree species, including Critically Endangered Vatica lanceifolia are under IUCN Red List Categories, thus stressing the need for conservation. Our findings suggest that conserving species diversity and carbon reserves in tropical forests would principally depend on minimizing forest loss and degradation.

Some of the Mechanisms for Coexistence of Tree Species Diversity in Tropical Forests: A Review of Effects of Tree Density Dependence

Tree communities contribute to maintenance of species diversity in tropical forests. Coexistence of many tree species is not without competition. Therefore, coexistence of tree species and size diversities occur sequentially or simultaneously in tropical natural forests. Understanding coexistence and competition mechanisms of tree species requires knowledge of interactions within and between species. However, many conservation efforts and strategies failed due to inability to identify and maintain functional coexistence mechanisms among tree species in the forest. Also, most trees died because of pressure on their habitats and not because of limiting growth resources. Hence, species identity, minimum distance and size of the neighbouring trees which are responsible for coexistence of competing trees in most tropical forests have not been explicitly reviewed. Therefore, this review evaluated some of the density dependent mechanisms for coexistence of tree species alpha diversity in tropical forests. Many interactive mechanisms are responsible for coexistence tree species in tropical forests. Inter- and intra-specific competitions are the most significant and both facilitate positive and negative density dependence. Therefore, switching from negative to positive density dependence may occur in some situations. Positive and negative density effects regulate species abundance and coexistence through conspecific and heterospecific structures. Aggregates of conspecific and heterospecific neighbours constitute forest spatial structure. Negative density interactions are mutually exclusive and basically ranged from effect of species identity of neighbours, distance to neighbours and tree size of the neighbours to reference trees in the community structures. Some mechanisms shorten distances for heterospecific than conspecific interactions. Conspecific structures improved survival and growth of rare tree species. Interactive mechanisms in tree community and population structures facilitate species diversity and size inequality, respectively.

长白山暗针叶林群落物种多样性维持机制

PDF HTML阅读 XML下载 导出引用 引用提醒 长白山暗针叶林群落物种多样性维持机制 DOI: 10.5846/stxb202202210407 作者: 作者单位: 作者简介: 通讯作者: 中图分类号: 基金项目: 国家自然科学基金项目（32001312） Species diversity maintenance mechanism of dark coniferous forests community in Changbai Mountain Author: Affiliation: Fund Project: The National Natural Science Foundation of China (General Program, Key Program, Major Research Plan) 摘要 | 图/表 | 访问统计 | 参考文献 | 相似文献 | 引证文献 | 资源附件 | 文章评论 摘要:植物群落物种多样性维持机制一直是生态学研究的热点话题，其中生态位理论和中性理论是被普遍接受的两种理论观点，但是目前关于生态位理论和中性理论在群落物种多样性维持中的相对重要性还没有统一定论。基于长白山暗针叶林群落数据，采用单物种-面积关系模型探究特定树种对邻域物种丰富度的影响，并借助同质性和异质性泊松零模型检验其显著性。（1）群落水平上，在3-15 m空间尺度上，促进种占据优势地位，在>15 m空间尺度上，中性种逐渐取代促进种起主导作用，抑制种比例较低，并且随着空间尺度变化幅度不大。（2）物种水平上，采用同质性泊松零模型检验树种对邻域物种丰富度的影响，臭冷杉、花楷槭、青楷槭在0-20 m空间尺度上对邻域物种丰富度增加起促进作用，黄花落叶松、鱼鳞云杉在0-20 m空间尺度上抑制了邻域物种丰富度增加。花楸树、黑桦和硕桦在全部研究尺度上表现为中性种，髭脉槭、大青杨、红松等在不同研究尺度上表现为不同的作用效果。剔除了生境过滤作用的异质性泊松零模型检验结果与同质性泊松零模型结果差异不显著，表明研究样地内生境过滤作用对多样性格局形成影响不大，各树种间的相互作用对群落物种组成影响较大，进一步证明了生态位理论能够解释长白山暗针叶林物种多样性维持。 Abstract:The maintenance mechanism of plant community species diversity has always been a hot topic in ecological research. Niche theory and neutral theory are two widely accepted theoretical viewpoints, but the relative importance of niche theory and neutral theory in the maintenance of community species diversity has not been unified. Based on the data of dark coniferous forest community in Changbai Mountain, this study used the individual species-area relationship model (ISAR) to explore the impacts of specific tree species on neighborhood species richness, and used homogeneity and heterogeneity Poisson zero model to test its significance. The results showed that:(1) at the community level, in the 3-15 m spatial scale, the promoting species occupied the dominant position. At scale >15 m, the neutral species gradually replaced the accumulators, the proportion of repellers species was low, and the change range with the spatial scale was small. (2) At the species level, the homogeneity Poisson zero model was used to test the influence of tree species on the neighborhood species richness. At the spatial scale of 0-20 m, Abies nephrolepis, Acer ukurunduense and Acer tegmentosum promoted the increase of species richness in the neighborhood, while Larix olgensis and Picea jezoensis inhibited the increase of neighborhood species richness. Sorbus pohuashanensis, Betula dahurica and Betula costata were neutral species at the scale of 0-20 m. Acer barbinerve, Populus cathayana, and Pinus koraiensis showed different effects on different scales. There was no significant difference between the results of heterogeneity Poisson null model excluding habitat filtering and homogeneous Poisson null model, indicating that habitat filtering had little effect on the formation of diversity pattern in the study plot. It was mainly due to the interaction between tree species contributed to the species composition structure of the community, which further proved that niche theory could explain the maintenance of species diversity in dark coniferous forest of Changbai Mountain. 参考文献 相似文献 引证文献

Spatial variation and determinants of woody plant species diversity in a semi-humid evergreen broad-leaved forest in the Jizu Mountains, Yunnan

Spatial variation and determinants of woody plant species diversity in a semi-humid evergreen broad-leaved forest in the Jizu Mountains, Yunnan

Understorey species distinguish late successional and ancient forests after decades of minimum human intervention: A case study from Slovenia

The main species composition drivers in temperate deciduous forests are environmental conditions, a stand's age and the site history, e.g., the succession stage and past land use, as well as disturbance regime and current management. We compared plant species diversity and composition in late successional and ancient forests, co-occurring on the same small river island applying species accumulation curves and nonmetric multidimensional scaling, respectively. Given the island's geomorphological characteristics, we expected these to be very similar before human intervention in the past. The forests experienced differing disturbance regimes in the past, while over the last 30 years, human intervention has been the same and reduced to a minimum. The ancient forest in this study had two major characteristics defining it as old, mature forest: continuity of presence for more than 200 years and specific composition. The late successional forest experienced major disturbance in the 20th century and was allowed natural regeneration by bordering on the ancient forest, representing a potential species pool, and by decades of minimum human intervention. Our results showed that, even though there was no difference in species richness, we could still detect differences between the forests, particularly in the abundance and species composition of the understorey, among which geophytes had the most indicative importance. To make our results useful on a broader scale, we composed from the literature a species list of plants indicative for ancient forest and tested its application. These results are important for distinguishing between old and mature secondary stands and particularly for identifying old forest stands, which should be conserved and, in the case of fragmented landscapes, included in a network connecting forest fragments.

Islandization and species diversity of semi-humid evergreen broad-leaved forests in the Central Yunnan Plateau

Islandization and species diversity of semi-humid evergreen broad-leaved forests in the Central Yunnan Plateau

The Zoʻé perspective on what scientists call “forest management” and its implications for floristic diversity and biocultural conservation

Indigenous perspectives on forest management are grounded in traditional ecological knowledge (TEK), so that socioculture influences the ways Indigenous Peoples transform their landscapes. However, how socioculture structures Indigenous perspectives on forest management is unclear. Moreover, little is known about the influence of Indigenous landscape transformations on forest succession and floristic diversity. Here, we test hypotheses from biocultural and ecological theories suggesting that: (i) key social-ecological relationships with specific taxa structure Indigenous perspectives on forest management; (ii) such relationships guide sustainable management that generates resilient forest regrowth; and (iii) this management promotes floristic diversity by acting as an intermediate disturbance. We collected information about cosmology, occupation history and management among the Zoʻé, in Brazilian Amazonia. We also carried out floristic inventories in old-growth forests and in old Zoʻé swidden-fallow areas to analyze forest structure and alpha- and beta-diversity along a gradient of forest successional stages. We show that the Zoʻé perspective on forest management is structured by an ethical principle involving a social-ecological relationship with different beings, especially the spider monkey (<em>Ateles</em> sp.). This relationship generates mobility among the Zoʻé that allows forest regrowth in their fallow areas, so that in 28 years, forest basal area may equal that of old-growth forests. Also, Zoʻé forest management has increased alpha- and beta-diversity by increasing species richness and diversity in intermediate secondary forests and promoting floristic turnover at the landscape-level. These results show that some aspects of Zoʻé cosmology influence forest disturbance regimes that generate a sustainable social-ecological system, therefore being key for Zoʻé well-being and local biodiversity conservation. We believe that Indigenous perspectives about forest management should be included in forest conservation efforts aimed at protecting Amazonian biocultural diversity, thus valuing TEK and engendering sustainable social-ecological systems.

Assessing Forest Cover Distribution, Species Diversity, and Richness of the Buffer Zone for Strategic Forest Management Planning for Nimule National Park, South Sudan

Assessing Forest Cover Distribution, Species Diversity, and Richness of the Buffer Zone for Strategic Forest Management Planning for Nimule National Park, South Sudan

Tree Species Diversity and Carbon Stock in Community and Religious Forests of Rupandehi, Nepal

Forest is one of the most important natural resources of the ecosystem which contributes in biodiversity conservation as well as plays a significant role in maintaining the earth’s climate by sequestrating atmospheric carbon. Tropical forests are rich in biodiversity and store large amounts of carbon. The studied Bolbum Community Forest (BCF) and Brahmakumari Global Religious Forest (BGRF) lie in tropical region between the altitudes 120 and 300 m asl in Rupandehi District of Nepal. The main objective of this research was to assess and compare tree diversities and carbon stocks in two different management regimes, namely, community forest and religious forest. Stratified random sampling technique was used for data collection. The allometric equation biomass-diameter regression (Model II) was used for estimation of carbon stock of tree species while Simpson and Shannon-Wiener indices were used to measure tree species diversity. The results showed that the carbon stock value was 27.15 t.ha-1 in BCF and 40.94 t.ha-1 in BGRF. The community forest had lower value of tree carbon stock than that of the religious forest. However, tree diversity was higher in BCF (25) than in BGRF (20). Shorea robusta was found to be the single dominant species in BGRF with higher basal area (102.24 m².ha-1) and contributed 56% of the carbon stock. The contribution of carbon stock of two co-dominant tree species in BCF were 32% for Shorea robusta and 26% for Terminalia anogeissiana. There was significant (p=0.05) positive relationship of carbon stock with basal area and DBH in both forest types.

Diversity and structure of forest species in Sarazin, Center Department, Haiti

The present study carried out in secondary tropical forests of Sarazin, 2nd communal section of Mirebalais, Haiti aims to describethe diversity and structure of forest species to promote their conservation. A systematic sampling consisting of four transects of10,000 m long and 1,000 m wide was carried out, in each one five square plots were evaluated (20 plots). The diversity of forestspecies was characterized by calculating diversity indices. The structure of the forest species was described through the distributionof individuals by diameter class with a width of 10 cm and by height class with a width of 5 m. The surveys show that the studyarea has a partial specific richness of 40 species divided into 38 genera and 23 families. The Fabaceae family was the mostrepresentative with 11 species, and the most abundant species was Prosopis juliflora. Natural and human disturbances influence thediametrical and vertical structure. The structural analysis showed that, despite the existence of a reasonable number of species, inmost cases they are trees in minimal quantities, small and sporadically distributed. Despite disturbances correlated withanthropogenic activities and extreme weather events, Sarazin's tropical forests have shown some resilience.

Fire and tree species diversity in tropical peat swamp forests

Tropical peat swamp forests contain diverse plant communities that support many endangered flora and fauna species. These forests are increasingly threatened by disturbances such as drainage, logging, and subsequent fire, yet little is known about tree species recovery from these threats.Tree species richness and diversity were measured in peat swamp forests of Central Borneo regenerating naturally after fires from 139 chronosequence plots. Our findings indicated that two to three decades after fire, similar levels of richness and diversity to relatively undisturbed reference forest are reached within sites. However, when averaged across landscapes our modelling shows that fires of average frequency of 50 years, or even 100 years, can substantially suppress tree species richness and diversity. Thus, even rare fires can reduce the species richness and diversity of tropical peat swamp forests.Two groups of tree species drove the difference in richness and diversity between disturbed and reference forests: ‘decreasers’, occupying recently burnt forest and declining with fire exclusion, and ‘increasers’, that were only present in less disturbed forests and absent or rare in recently burnt forests. The decreasers were more common than the increasers.We conclude that peat swamp forests can recover adequately from fires through natural regeneration, and it is possible that artificial planting may speed up this process. Where possible, excluding fire from tropical peat forests will help to maintain the diversity of these threatened ecosystems and promote their recovery.

Dietary Diversity of Sumatran Elephants (Elephas Maximus Sumatrensis) At Elephant Training Center Way Kambas National Park

The Sumatran elephant (Elephas maximus sumatrensis) is a rare animal that is threatened with extinction, so conservation is needed. Elephant Training Center (PLG) Way Kambas National Park is one form of in situ conservation. The availability of natural food is one of the factors that determine the success of conservation. The purpose of this study was to determine the composition and diversity of forest community species as elephant feeding habitats, and to determine the types of plants that elephants eat. Purposive sampling was used to collect data using nested plots, 1 x 1 m2 for seedlings and undergrowth, 5 x 5 m2 for saplings, 10 x 10 m2 for poles and 20 x 20 m2 for trees. The results showed that the vegetation making up the forest as a grazing habitat for Sumatran elephants consisted of 27 species belonging to 19 families. The vegetation that elephants eat is Symplocos thwaitesii, Imperata cylindrica, Colopogonium sp., Bridelia monoica, Vitex pinnata, Shorea sp., Pennisetum purpureum, Gluta renghas, Mimosa pudica, and Melastoma. The most widely available plant species belong to the Poaceae and Leguminoceae families. The diversity index of the seedling level of 2.49 was categorized as high, while the vegetation level of sapling, poles, and trees was categorized as low. Meanwhile, the evenness index at the seedling, sapling, pole and tree levels was categorized as high. The richness index for all levels of growth is categorized as moderate.

Microclimate, soil chemistry, and microbiota fail to explain Euphorbia dendroidesJanzen‐Connell pattern in a shrubland

AbstractNegative plant–soil feedback can cause density and distance effects that lead to Janzen–Connell (JC) distribution. The JC hypothesis has been proposed to explain the high species diversity in tropical forests, but it has been rarely tested in species‐rich Mediterranean shrublands. In this study, we assessed whether the JC hypothesis could explain Euphorbia dendroides recruitment pattern under conspecific conditions, that is, mother plant and the canopy of Pistacia lentiscus, Juniperus phoenicea, Myrtus communis, Rosmarinus officinalis, and Olea europaea. We examined whether soil chemistry and/or soil microbiota, characterized by both bacterial and fungal communities, explained the observed JC pattern. We also explored differences in microclimate among shrub species by monitoring air temperature and light availability at different times of the year. Euphorbia recruits were almost absent under the canopy of conspecifics, being more abundant at the edge of the canopy, which fits the JC pattern. Interestingly, we also found a high density of Euphorbia recruitment under heterospecific canopies, that is, O. europaea and J. phoenicea, but a very low density under other heterospecific canopies, for example, R. officinalis and P. lentiscus. Although shrubs have a species‐specific microbiota signature under their canopy, neither the accumulation of species‐specific pathogens nor soil chemical properties explain the observed JC pattern. Despite finding that shrubs buffer high temperatures in summer, the observed microclimatic difference failed to explain the recruitment pattern. We conclude that JC is prevalent in this species‐rich Mediterranean shrubland, but the underlying mechanism remains to be investigated and clarified.

Spatially explicit assessment of genetic variation to inform conservation effort for an endangered Mediterranean conifer, Cedrus atlantica.

Preserving the genetic diversity of forest species is critical for maintaining their adaptive potential and allowing for generation turnover in forest ecosystems. Considering an uncertain future, it is necessary to establish reliable genetic conservation strategies to optimize the genetic variation preserved within populations in a spatially explicit context to assist decision-makers. Hence, we aimed to incorporate genetic information into spatially designed conservation actions. Cedrus atlantica is a large, long-lived conifer native to the mountains of North Africa, threatened by extinction. The relevant genetic units for conservation were selected using Bayesian analysis. The relative contribution of the populations to the genetic pool that maximized the species' genetic diversity was calculated to design an optimal seed bank. Finally, the relationship between the genetic composition and bioclimatic variables was estimated and projected throughout the study area under current and future climatic conditions. Three relevant genetic units were found for C.atlantica conservation that maximizes genetic diversity in a spatial context. Bioclimatic variables with the highest influence on genetic composition were closely related to climate warming and decreased soil water availability. We identified the role of genetic markers in designing a reliable conservation strategy for forest trees considering climate change, increased deforestation, and aridity. Projections of genetic composition due to the climate in the study region of North Africa provide spatially explicit guidance for optimizing the selection and preservation of seed banks.

Impact of human foraging on tree diversity, composition, and abundance in a tropical rainforest

AbstractTropical forest tree communities are structured by a range of large‐scale drivers including elevation, certain high‐impact anthropogenic activities (e.g., deforestation), and fires. However, low‐impact human activities such as foraging may also be subtly but notably altering the composition of tropical forest tree communities. The study assessed the (i) differences in species diversity, patterns of relative abundance, and pairwise beta diversity between trees with edible and inedible fruits and seeds along an elevation gradient, and (ii) impact of human foraging on the forest tree communities in Oban Division of Cross River National Park, Nigeria. Fifteen permanent 40 by 40 m plots were established along an elevational gradient (120–460 m above mean sea level). All trees of 0.1 m diameter at breast height (dbh) and above were measured, identified, and, with the aid of structured questionnaires, classified into those with edible and inedible fruits/seeds. A total of 35 edible species with density of 128 stems/hectare and basal area of 11.99 m2/hectare, and 109 inedible species with density of 364 stems/hectare and basal area of 22.42 m2/hectare were sampled. However, the evenness of edible and inedible species was similar at pooled and plot levels. For inedible species, there was a positive relationship between pairwise beta diversity and elevation, and this was driven mainly by turnover. In contrast, edible species exhibited a non‐significant trend between elevation and beta diversity. Thus, the study showed that human foraging of edible fruits may have subtly influenced patterns of species diversity and community structure in this tropical forest.