Forest Biodiversity Research Articles

Positive feedbacks and alternative stable states in forest leaf types

The emergence of alternative stable states in forest systems has significant implications for the functioning and structure of the terrestrial biosphere, yet empirical evidence remains scarce. Here, we combine global forest biodiversity observations and simulations to test for alternative stable states in the presence of evergreen and deciduous forest types. We reveal a bimodal distribution of forest leaf types across temperate regions of the Northern Hemisphere that cannot be explained by the environment alone, suggesting signatures of alternative forest states. Moreover, we empirically demonstrate the existence of positive feedbacks in tree growth, recruitment and mortality, with trees having 4–43% higher growth rates, 14–17% higher survival rates and 4–7 times higher recruitment rates when they are surrounded by trees of their own leaf type. Simulations show that the observed positive feedbacks are necessary and sufficient to generate alternative forest states, which also lead to dependency on history (hysteresis) during ecosystem transition from evergreen to deciduous forests and vice versa. We identify hotspots of bistable forest types in evergreen-deciduous ecotones, which are likely driven by soil-related positive feedbacks. These findings are integral to predicting the distribution of forest biomes, and aid to our understanding of biodiversity, carbon turnover, and terrestrial climate feedbacks.

Small oases below the canopy: The cooling effects of water-filled tree holes on the local microclimate in oak-dominated stands

The relevance of forests in mitigating biodiversity loss and the negative effects of climate change on the biota is largely shaped by below-canopy microclimatic conditions, which are buffered, cooler and more humid compared to adjoining open habitats. Water-filled tree holes (dendrotelms, DTs) are special tree-related microhabitats that host semi-aquatic communities and are important substrates or water sources for numerous taxa (e.g., birds, mammals, insects, fungi, bryophytes). Despite their microrefugia-role might be more pronounced under climate change-induced drought events, little is known about their microclimate and its potential drivers.In an abandoned Turkey oak-dominated coppice stand in Hungary, the microclimates of 80 paired dendrotelms and adjacent forest plots were measured in the summer of 2021. Compared to nearby open areas, under closed forests, air temperature maxima were up to 5 °C cooler, DTs had an additional negative offset of 2.5 °C and increased air humidity by 15 percentage points (5% vs. 20 %). The local microclimate of DTs and the adjacent closed forest differed significantly in means and extremes of air temperature, relative humidity and vapour pressure deficit, which was mainly driven by DT entrance area and water volume and seemed independent from local stand structure. On the contrary, nearby below-canopy microclimate was shaped by the distance from forest edge, incoming light and tree density. Water volume in DTs also influenced local forest microclimates up to 0.5–1 m from the entrances.As the frequency and severity of extreme weather events such as heatwaves are likely to intensify due to climate change, the importance of microhabitats and habitat trees for invertebrates and vertebrates will increase further, and will additionally contribute to the microclimatic refugia role of forests. Active protection of veteran trees under the scheme of continuous cover forestry or conservation-oriented management is essential facing climate change to mitigate its negative effects on forest biodiversity.

Assessment of plant biodiversity in tropical dry forests of Sialkot, Pakistan; insight into environmental, anthropogenic influence and conservation strategies

The tropical dry forests (TDF) have an enormously rich flora and fauna that offer various ecological services to the surrounding human societies. Biodiversity assessment is mandatory for implementing any sustainable forest management policy, which is why it is one of the important criteria and indicators currently used. Threats to TDF biodiversity are the primary challenges arising from environmental concerns caused by anthropogenic activity leading to global warming issues. The study aimed to investigate the vegetation assessment and several environmental and anthropogenic variables influencing forest biodiversity from 5 threatened forest sites of District Sialkot (Ghalotian, Kishan Garh, Daburgi Chanda Singh, Pir Kot, and Ghulab Garh), Pakistan. We collected 170 distinct plant species, including 135 dicots, 27 monocots, seven pteridophytes, and one bryophyte, categorized into 138 genera and 62 families, divided into 114 herbs, 32 trees, and 24 shrubs. The phytosociological analysis described the quantitative characteristics, including % frequency, % density, % cover, and importance Value Index (IVI) of all forest areas. Gulab Garh forest has the richest biodiversity forest area, and herbs are the dominant species that have been documented. Environmental factors such as temperature, precipitation, organic matter, soil pH, Ca+2, Mg+2, Na+, Cl−, and electric conductivity (EC) strongly affect forest vegetation investigated by principal coordinate analysis. Shannon and Simpson’s diversity indexes reveal that all sites contain loamy and sandy soil and display a significant relationship between alpha diversity and richness. Increasing trends in temperature and decreasing trends in rainfall suggested that climate significantly affects the Sialkot region’s plant biodiversity. SWOT analysis highlighted that population growth leads to increasing anthropogenic activities such as constructing housing societies and roads, inadequate farming, and excessive grazing, impacting the forest vegetation and altering TDF ecosystem properties/services and functioning. Our findings reinforce the vegetational assessment and importance of local forest biodiversity and significant environmental drivers that influence the plant species diversity in TDF areas. Future conservation strategies are suggested to reduce unlawful resource consumption, restore plant biodiversity in designated protected areas, and conserve rare species locally.

Measuring biodiversity with sound: How effective are acoustic indices for quantifying biodiversity in a tropical dry forest?

AbstractLarge‐scale biodiversity conservation and management necessitate rapid assessment tools and technologies. Indices derived from passive acoustic data offer a novel solution for rapid biodiversity monitoring. Although these indices quantify vocalizing biodiversity at a site, previous studies indicate inconsistencies in the indices' performance across different biomes. We tested the efficacy of seven acoustic indices—acoustic complexity index, acoustic diversity index, bioacoustic index (BI), acoustic entropy index, total entropy (H), normalized difference soundscape index, and number of peaks in an understudied biome, tropical dry forests, in central India. We measured the relationship between every index and a combination of these indices with a biodiversity metric, avian species richness. We found a weak correlation between individual indices and species richness (0.00 ≤ R ≤ 0.35), while a combination of indices was comparatively better at predicting species richness (R2 = 0.54). Although BI performed better than all other indices, our results indicate that acoustic indices do not accurately quantify avian species richness in this forest in central India. However, combining multiple indices increases their efficacy, limitedly. We recommend evaluating the efficiency of acoustic indices, especially in underrepresented habitats, before their application in avifauna‐based rapid acoustic surveys.

Identification of main variables in forest management for recovery of endemic species habitat in burned areas of southern Chile

Wildfires are among the most serious disturbances that affect forest biodiversity, damaging both flora and fauna. In some burned areas, vegetation recovery is a long and complex process that requires the support of restorative actions. This study evaluated changes in forest structural features after a fire that affect habitat suitability for Rhinocryptids, an endemic group of bird species that are indicators of biodiversity in the temperate forests of South America. The study area was the Malleco National Reserve, Chile, where the main ecosystems are temperate forests. Four species from the Rhinocryptidae family of birds were used as bioindicator species. This group of species is endemic to temperate forests in South America. After fires occurred in 2002 and 2015, affecting temperate forests dominated by several Nothofagus species, two field inventories were carried out in 2016 and 2018. These inventories recorded the presence of Rhinocryptids and some forests structural features. Differences between the two stages of forest regeneration were assessed using statistical tests (T-test and Wilcoxon–Mann–Whitney test) and a classification model was proposed to determine the presence of Rhinocryptidae species. The statistical analysis of forest structural features showed that the variables more relevant in the habitat recuperation are vertical stratification (p-value < 0.001) and understory cover (p-value = 0.053). The trained decision tree to predict the presence of Rhinocryptidae species had an accuracy of 65.22%. This model showed that the coexistence of more than one Rhinocryptidae species occurs when vertical stratification is not mono-stratified and the density is lower than 335 trees ha−1. Our results can help forest managers to consider forest structure as a suitable habitat for certain major wildlife species when implementing post-fire recovery plans.

Impact of fire severity on forest structure and biomass stocks using NASA GEDI data. Insights from the 2020 and 2021 wildfire season in Spain and Portugal

Wildfires have been progressively shrinking the C sink capacity of forest accelerating climate change effects on forest biodiversity, especially where megafires are recurrent and of increased frequency such as in the Mediterranean. Data from The Global Ecosystem Dynamics Investigation (GEDI) mission can inform on changes on forest structure to inform on fire impacts on vegetation. In this study, we assessed the performance of GEDI at measuring biomass and structural change from wildfires using the 2020/21 summer fire seasons in Spain and Portugal. The GEDI hybrid-inference method was used to calculate mean and total biomass in pre- and post-fire stages, while GEDI footprint data was further used to explain the fire severity classes derived from optical data. Our results showed the increasing impact of wildfires on biomass stocks and GEDI ecological metrics by increasing fire severity. More than over biomass stocks, severe fires substantially altered trends in structural metrics such as plant area volume density. The integration of GEDI metrics to explain fire severity had an accuracy of 52% considering five severity classes and an accuracy of 69% when considering the three main classes: unburned, moderate and high. Structural metrics from GEDI can be used to improve optical-based fire severity estimates used globally and to evaluate potential fire impacts based on time-series of GEDI tracks as showcased in the study, but also to measure forest recovery between fire seasons. The extension of GEDI is a major support for wildfire mapping efforts, integrated approaches to capture the increasing impact of fire on forest biodiversity and the monitoring of changes in carbon stocks.

“Biodiversity Offsetting” in Uganda’s Protected Areas: A Pathway to Restoration of Forest Biodiversity?

With limited national financing for conservation, there is an increasing interest in using biodiversity offset funds to strengthen protected area management. Offsetting measures can potentially be used in the restoration of degraded protected areas. However, there are concerns related to the uncertainty of restoration outcomes and time-lags before the expected benefits can be observed. Using a case of the Gangu Central Forest Reserve in central Uganda, we contribute empirical findings showing the potential and limitations of biodiversity offsetting by means of the restoration of a degraded forest reserve. We use forest cover change analysis and community surveys to determine forest changes after eight years of offset implementation, and forest inventories to analyse the current forest structure and composition to ascertain taxonomic diversity recovery. The results revealed that biodiversity offsetting led to a 21% increase in Tropical High Forest cover, and enhanced restoration of forest species composition and diversity. However, attaining permanence of the restoration benefits requires the regulation of community forest resource access and use. Strengthening forest management capacity to monitor the offset sites and compensating impacted communities for foregone forest resource benefits are crucial for the successful implementation of biodiversity offsets.

Motivation towards Conserving a Rich Forest Biodiversity

This research study interrogated the benefits that accrued to the Kaya Forest-neighbouring communities as the key motivator in the sustainable conservation of forests. While forests are threatened by deforestation and degradation worldwide due to the overemphasis of their direct economic benefits, socio-cultural considerations have in some cases, protected this rich ecosystem. A case study carried out in Kaya Forests of the Kwale County, Kenya has shown that intangible benefits, not considered in the direct harvest of forests, could be used to reverse the trend in the loss of forests. Data collected questionnaires, interviews, focus group discussions and observations has shown this to be the case. The findings of the study were such that sacred forests offered more benefits than the other forms of forests, and that there was equity in the sharing of these benefits among community members in this category. The study however, revealed that for sustainable conservation efforts, it was prudent to consider both the economic and social benefits of this resource as a whole. Consequently, the study is recommending the need to identify and repackage such benefits and to sensitize the community on the benefits that accrue from such arrangement.

Clear-cuts support the metapopulation of a critically endangered butterfly

Clear-cutting is believed to have a negative impact on forest biodiversity, but numerous studies have also shown its positive effects, especially in temperate and boreal regions. This phenomenon is mainly related to the creation of early successional habitats that serve as temporary meadows. Among the species that benefit the most are those associated with semi-natural grasslands, i.e. biotopes that have been disappearing from the landscape due to agricultural intensification. A good example is the Danube Clouded Yellow Colias myrmidone, one of the most endangered butterflies in Europe. Its last lowland metapopulation in the EU exists in the Knyszyn Forest (north-eastern Poland), but the species occurrence is limited to the eastern parts of this large forest complex. All currently known habitats are forest clear-cuts located mainly on former agricultural land, i.e. mostly extensively used pastures that were afforested in the 20th century. Chamaecytisus ruthenicus, the only local larval food plant of C. myrmidone, is currently found almost exclusively in first-generation forests. Logging allows the host plants to flourish, and clear-cuts are colonized by the butterfly. In 2022, intensive mark-release-recapture studies were carried out in the focal metapopulation. The estimated metapopulation size was 4643 adults, indicating a six-fold increase compared to previous studies conducted in 2017. This was plausibly mainly due to the increase in the area of potential habitats, as butterfly densities were very similar in both seasons. The improved connectivity between habitat patches resulted in a very high proportion of dispersing individuals successfully reaching other patches, which is in contrast to the dispersal mortality of ca. 50% observed five years earlier. A relatively high mobility was also observed in the case of the much smaller spring generation. To our knowledge, this is the first study to document a reversal of selection against dispersal and it demonstrates that such changes can occur relatively quickly, i.e. within a few generations. In order to ensure the long-term persistence of the viable C. myrmidone metapopulation and mitigate the negative effects of climate change, a network of stable forest-steppe-like habitats in combination with the creation of clear-cuts in forest stands with presence of C. ruthenicus would be optimal. To achieve this, we recommend leaving some selected clear-cuts without replanting to restore grasslands (through grazing and removal of excess trees, shrubs and invasive plants), while the suitability of ephemeral habitats could be improved through appropriate silvicultural measures.

Post‐drought community turnover and functional redundancy in a tropical forest understorey

AbstractQuestionsDrought events are increasingly frequent, threatening the biodiversity of tropical forests. The understorey comprises a large fraction of the total plant species richness of these systems with the presence of highly diverse angiosperm families. Here, we quantified the effects of a drought on abundance and functional structures and on the ecosystem functioning of Rubiaceae assemblages along a topographic gradient.LocationMata das Flores State Park, an Atlantic Forest fragment in southeast Brazil.MethodsTwo vegetation surveys were performed: one during an El Niño‐induced drought, and the other three years after this drought. Abundance and functional structures were assessed using the 16 most‐abundant species of Rubiaceae, which comprised 92% of the total abundance. A litter decomposition experiment was carried out to estimate the percentage of mass loss by the Rubiaceae species. We carried out Procrustes analyses on abundance and functional structures and used Generalized Linear Mixed Models to test the effects of drought and topographic habitats on taxonomic and functional compositions, and mass loss.ResultsWe found that the functional structure and mass loss remained constant despite significant changes in the abundance structure after the drought.ConclusionThe evidence points to the maintenance of ecosystem functioning through functional redundancy, because functionally similar less‐abundant species replaced each other after the drought. We show that swarms of species can maintain biological diversity and stability in ecosystem functioning under drought in the understorey of a tropical forest.

Modelling and Mapping of Forest Biodiversity Indicators Using Sentinel-2 and PlanetScope Remotely Sensed Data

Tropical montane forests harbour exceptionally high biodiversity yet face severe threats from human activities. Assessing forest biodiversity over large areas is crucial yet extremely challenging. Remote sensing provides an efficient monitoring solution, but few studies have focused on Tanzania's diverse, montane forests. We collected field data on tree species composition within 159 plots across montane forests in Tanzania's West Usambara region. We calculated species richness, evenness, and Shannon diversity index as indicators of tree diversity. Using Sentinel-2 and PlanetScope satellite imagery, we derived spectral, textural, and vegetation index predictors to model these indices via generalized additive models and extreme gradient boosting. PlanetScope-based XGBoost models performed best, explaining 19.7% of variation in Shannon diversity. Incorporating textural predictors further improved model accuracy. Despite inherent challenges in modelling complex tropical forests, our findings demonstrate promising potential of Sentinel-2 and PlanetScope for regional biodiversity monitoring where field surveys are limited. Further research could enhance these initial results by leveraging higher resolution data and increasing field sampling for effective monitoring of tropical biodiversity.

Sustainable Development versus Extractivist Deforestation in Tropical, Subtropical, and Boreal Forest Ecosystems: Repercussions and Controversies about the Mother Tree and the Mycorrhizal Network Hypothesis.

This research reviews the phenomenon of extractive deforestation as a possible trigger for cascade reactions that could affect part of the forest ecosystem and its biodiversity (surface, aerial, and underground) in tropical, subtropical, and boreal forests. The controversy and disparities in criteria generated in the international scientific community around the hypothesis of a possible link between "mother trees" and mycorrhizal networks in coopetition for nutrients, nitrogen, and carbon are analyzed. The objective is to promote awareness to generate more scientific knowledge about the eventual impacts of forest extraction. Public policies are emphasized as crucial mediators for balanced sustainable development. Currently, the effects of extractive deforestation on forest ecosystems are poorly understood, which requires caution and forest protection. Continued research to increase our knowledge in molecular biology is advocated to understand the adaptation of biological organisms to the new conditions of the ecosystem both in the face of extractive deforestation and reforestation. The environmental impacts of extractive deforestation, such as the loss of biodiversity, soil degradation, altered water cycles, and the contribution of climate change, remain largely unknown. Long-term and high-quality research is essential to ensure forest sustainability and the preservation of biodiversity for future generations.

Effects of clonal fragmentation on Pyrrosia nuda depend on growth stages in a rubber plantation.

Clonal fragmentation helps to assess clonal plants' growth resilience to human and environmental disturbance. Although clonal integration in epiphytes in tropical rubber plantations is important to understand their role in enhancing biodiversity and ecosystem services, research on this subject is limited. These plantations are typically monospecific economic forests that face increased anthropogenic disturbances. In this study, we selected the clonal fern Pyrrosia nuda to study its survival status, biomass, maximum quantum yield of photosystem II (Fv/Fm), and frond length in response to the level of clonal fragmentation in a tropical rubber plantation. The results showed that (1) clonal fragmentation significantly negatively affected the survival rate, biomass, and frond length of clonal plants, but with minimal effects on Fv/Fm at different growth stages; (2) the performance of a ramet (e.g., biomass or frond length) increased with ramet developmental ages and decreased with the number of ramets in a clonal fragment. The age-dependent impacts of clonal fragmentation provide insights into the biodiversity conservation of epiphytes and forest management in man-made plantations. Therefore, to better conserve the biodiversity in tropical forests, especially in environment-friendly rubber plantations, there is a need to reduce anthropogenic disturbances and alleviate the level of fragmentation.

Comparative assessment of woody species diversity, structure and carbon stock of PFM and Non-PFM forests and its implication for REDD+ in Ethiopia

Maintaining forest biodiversity and carbon sequestration potential of forest resources enhances the provision capacity of forest ecosystem services. Experience from around the world and in Ethiopia has shown that shifting forest management from state-centred to community-centred arrangement can result in a better forest stock. Therefore, this study examined the status of woody species diversity, regeneration and total living biomass carbon stock of forests under participatory forest management (PFM) and the adjacent state managed non-participatory forest management (Non-PFM) in South eastern Ethiopia and implications to REDD+. Data were collected from 89 (44 PFM and 45 Non-PFM) nested circular plots from four PFM and three Non-PFM selected forest sites with transects laid systematically. Tree DBH and height were measured, the number of saplings, seedlings, mature trees were counted and species names were recorded. Woody species diversity was estimated using shannon, simpson, and evenness diversity indices. A total of 29 and 23 woody species were recorded in PFM and Non-PFM forests, respectively. Woody species diversity did not show significant difference between PFM and Non-PFM forests but it was relatively higher in PFM forest. The density per hectare of seedlings, sapling and mature trees were significantly greater in PFM forest than in Non-PFM forest. The mean aboveground biomass carbon stock of PFM forest (225.50±26.54) was significantly greater than that of the Non-PFM (156.24±15.72) forest. Hence, managing forests through participatory approaches contributes to the enhancement of sustainable management and climate change mitigation potentials through reducing emission from deforestation and forest degradation.

Adaptive monitoring in action—what drives arthropod diversity and composition in central European beech forests?

Recent studies suggest that arthropod diversity in German forests is declining. Currently, different national programs are being developed to monitor arthropod trends and to unravel the effects of forest management on biodiversity in forests. To establish effective long-term monitoring programs, a set of drivers of arthropod diversity and composition as well as suitable species groups have to be identified. To aid in answering these questions, we investigated arthropod data collected in four Hessian forest reserves (FR) in the 1990s. To fully utilize this data set, we combined it with results from a retrospective structural sampling design applied at the original trap locations in central European beech (Fagus sylvatica) forests. As expected, the importance of the different forest structural, vegetation, and site attributes differed largely between the investigated arthropod groups: beetles, spiders, Aculeata, and true bugs. Measures related to light availability and temperature such as canopy cover or potential radiation were important to all groups affecting either richness, composition, or both. Spiders and true bugs were affected by the broadest range of explanatory variables, which makes them a good choice for monitoring general trends. For targeted monitoring focused on forestry-related effects on biodiversity, rove and ground beetles seem more suitable. Both groups were driven by a narrower, more management-related set of variables. Most importantly, our study approach shows that it is possible to utilize older biodiversity survey data. Although, in our case, there are strong restrictions due to the long time between species and structural attribute sampling.

Evaluating the definition and distribution of spring ephemeral wildflowers in eastern North America.

The herbaceous layer accounts for the majority of plant biodiversity in eastern North American forests, encompassing substantial variation in life history strategy and function. One group of early-season herbaceous understory species, colloquially referred to as spring ephemeral wildflowers, are ecologically and culturally important, but little is known about the prevalence and biogeographic patterns of the spring ephemeral strategy. We used observations collected by the Global Biodiversity Information Facility (GBIF) to quantify the ephemerality of 559 understory forb species across eastern North America and classify them according to a continuous ephemerality index (ranging from 0 = never ephemeral to 1 = always ephemeral). We then used this information to model where ephemeral forbs were most common across the landscape with the goal of identifying geographic and environmental drivers important to their distributions and ranges. Only 3.4% of all understory wildflower species were spring ephemerals in all parts of their range, and 18.4% (103 species) were ephemeral in at least part of their range. Spring ephemerals peaked in absolute species richness and relative proportion at mid latitudes. Spring ephemeral phenology is an important shade-avoidance strategy for a large segment of the total understory species in temperate deciduous forests. In North America, the strategy is relatively most important for forest understories at mid latitudes. The definitions of spring ephemerality we provide here serve as an important ecological context for conservation priorities and to evaluate responses of this biodiverse group to future environmental change.

Mixed-Species Stands Improve the Coordination between Leaf and Fine Root Traits in a Common Garden Experiment

The coordination between leaf and root traits is conducive to an integrated understanding of whole-plant ecological strategies and reveals how community composition and diversity contribute to defining the functions and services of ecosystems. However, there is limited understanding regarding the impact of species richness and trait categories on the coordination between leaf and root traits. Based on a 9-year common garden experiment, we investigated the leaf and fine root traits of 56 plots (25.8 m × 25.8 m) encompassing various trait categories (trait categories were defined according to the root depth, leaf habit, and mycorrhizal type) and different levels of species richness (1, 2, 4, 8) in the context of a forest biodiversity and ecosystem functioning experiment conducted in subtropical China (BEF-China). We found the following: (1) Our findings indicate that there was generally a significant difference in leaf traits, occasionally in absorptive root traits, and no difference in transport root traits between different trait categories. (2) Conversely, species richness significantly influenced all transport root traits except root nitrogen and most leaf and absorptive root traits. (3) The results demonstrated that trait categories played a crucial role in the coordination between leaf and fine root traits. Additionally, the coordination between leaf and fine root traits increased with higher species richness, particularly in deep-rooted, evergreen, and ectomycorrhizal fungi species. Furthermore, the coordination between leaf and fine root traits was significantly lower in monocultures compared to four- and eight-species mixtures. These results suggest that a significant mixture effect exists in the coordination between leaf and fine root traits due to the comprehensive and divergent capture of above- and belowground resources and reduced intraspecific competition. Therefore, compared to monocultures, mixed-species stands can enhance the coordination of leaf and fine root traits, and it is advisable to establish forests with mixtures of more than four species, dominated by deep-rooted, evergreen, and ectomycorrhizal fungi species, to maintain ecosystem stability and functional integrity.

Factors Affecting Radial Increment Dynamics in Lithuanian Populations of Common Juniper (Juniperus communis L.)

Although common juniper (Juniperus communis L.) is a widely spread species and important for the forest biodiversity and economy in many European countries, it remains one of the least studied coniferous species. This research is the first attempt to evaluate the factors affecting the increment of Juniperus communis in Lithuanian populations. The aim of this article is to evaluate the patterns of radial increment in Juniperus communis and to identify the key factors influencing the increment. We collected stem discs from 160 junipers in 8 stands distributed in the different regions of Lithuania and performed the tree-ring analysis. All studied junipers expressed a pronounced eccentricity of the stem. The results of our study revealed four patterns of Juniperus communis’ radial increment, which are strongly dependent on the granulometric properties of the soil and hydrologic conditions. The effect of climatic conditions on the Juniperus communis increment was strongly dependent on the terrain; however, most of the junipers had a positive reaction to the temperatures in April, July, and August and to the precipitation in February.

Patterns and drivers of tree species diversity in a coniferous forest of northwest China

IntroductionUnderstanding the pattern of species diversity and underlying ecological determinants driving a forest ecosystem is fundamental to conservation biology and forest management. Boreal forests play an irreplaceable role in providing ecosystem services and maintaining the carbon cycle globally, yet research attention remains disproportionately limited and lacking throughout time.MethodsBased on field measurement data from a large (25 ha) fully-mapped coniferous forest plot, the present study quantified patterns of species diversity and their determinants in Kanas of Xinjiang, northwest China. We applied linear regression analysis to test the effects of biotic and soil factors on alpha-diversity and local contribution of beta diversity (LCBD), and then we adopted path analysis to test the determinants that affected the species diversity index.Results and discussionOur results revealed that alpha-diversity indices did not vary greatly across different subplots, and richness value (between 2 and 6) was low in Kanas. Noteworthy is the discerned negative association between the average diameter at breast height (DBH) and species richness, suggesting that areas with smaller DBH values tend to harbor greater species richness. For beta-diversity, a higher value was observed in the substory layer (0.221) compared to both the canopy layer (0.161) and the understory layer (0.158). We also found that the species abundance distance matrix of biological and soil environmental factors were significantly correlated with species geographic distance matrices. More importantly, our results showed that average DBH and soil pH would affect the alpha diversity indices, and average DBH, soil Ph, average height and soil total Phosphorous would affect the beta diversity indices. Soil pH also indirectly affected the LCBDunder, LCBDsub, and LCBDcan (p ≤ 0.001), upon mediation of alpha diversity indices. Overall, our results provide crucial revelations about species diversity patterns in boreal forests, and insights that can support the protection of forest biodiversity in China.

Anthropogenic Pressures on Gorillas: A Case of Grauer’s Gorillas in Maiko National Park, the Democratic Republic of Congo

Anthropogenic activities put biodiversity under pressure, adversely affecting the forest ecosystem and wildlife habitats. Habitat disturbance and modification are among the main threats to animal populations in tropical forests. In the Democratic Republic of Congo (DRC), Grauer’s gorillas (Gorilla beringei graueri) are continuously threatened through forest encroachment for agricultural expansion, human settlements, new refugee camps, illegal logging, and mining across the country. Moreover, poaching and bushmeat trafficking continuously threaten gorillas’ existence. These drivers increase the proximity of humans and the risk of disease transmission. The emerging and existing zoonotic diseases, including Ebola, are continuously impacting gorillas’ lives. All of these pressures combined are disrupting natural behavior patterns and are leading to the decline in the Grauer’s gorillas’ population. Therefore, this review scrutinizes findings on the anthropogenic pressures on the habitats and survival of Grauer’s gorillas. Also, it is important to engage with people for the shared conservation role and ecotourism to support the conservation of forest biodiversity and Grauer’s gorillas’ habitats, particularly for the Maiko National Park in the DRC.