Mean Species Abundance Research Articles

Global sustainability scenarios lead to regionally different outcomes for terrestrial biodiversity

Abstract Mitigating climate change (CC) and reversing biodiversity decline are urgent and interconnected global priorities. Strategies to address both crises must consider the relationships, synergies and trade-offs between key response measures, including sustainable production and consumption patterns, protected areas (PAs) and climate mitigation policy (CP). In this paper, we review a large set of scenarios (n = 96) from the Integrated Model to Assess the Global Environment (IMAGE) describing future development of land use, greenhouse gas emissions and their impact on CC and biodiversity. We calculate the global mean temperature increase (GMTI) and the Mean Species Abundance (MSA) of plants, a metric indicative of local terrestrial biodiversity intactness. The set includes scenarios with and without specific CP to address CC, PA for biodiversity and demand and supply sustainability measures such as increased energy efficiency and reduced meat consumption. Our findings indicate that scenarios with integrated measures can prevent biodiversity loss at the global scale, yet with clear regional differences. By 2050, 15 out of 30 (50%) scenarios with at least 30% of global land as PAs show positive MSA changes in grasslands and tropical non-forests (Grass & TnF), but only 1 (3%) does so in tropical forests (TF). We demonstrate that pasture and food/feed crops are the main drivers of MSA loss in Grass & TnF and that scenarios with high levels of PAs prevent land conversion and increase biodiversity. By 2100, 28 out of 46 (60%) scenarios with mitigation measures to restrict CC to 2 °C or less in 2100 result in positive MSA changes in TF, but only 13 (28%) do so in Grass & TnF, reflecting the larger impacts of land use change in the latter region. These results underscore the importance of time and regionally-tailored approaches to address the biodiversity and CC crises.

The Assessment of Biodiversity Changes and Sustainable Agricultural Development in The Beijing-Tianjin-Hebei Region of China

In the face of a series of challenges, such as climate change, population growth, and agricultural intensification, as well as the issue of how to promote sustainable development and guarantee food security, biodiversity, with its unique genetic, ecological, and traditional socio-cultural values, has become an important way to solve this dilemma. Urban biodiversity has continued to decline in recent decades due to rapid urbanization. The agroecosystem health of the Beijing-Tianjin-Hebei region, a typical urban agglomeration economic area, is facing a critical situation. Therefore, assessing the potential of ecosystem diversity in the Beijing-Tianjin-Hebei region and exploring the assessment mechanisms and methods of ecosystem health can provide theoretical support for biodiversity conservation and utilization. In this thesis, the overall ecosystem health of the Beijing-Tianjin-Hebei region was assessed based on the land cover data from 1992 to 2022 and the projected land cover data up to 2032, as well as using the habitat quality indicated by the Fragstats and InVEST models and the landscape pattern index, habitat quality, and mean species abundance (MSA) indicators of the GLOBIO module. The main results are as follows: Habitat quality and mean species abundance (MSA) in the Beijing-Tianjin-Hebei region were observed to show a continuous downward trend over 40 years from a landscape level perspective, and landscape fragmentation due to urbanization was the main reason. Habitat loss and habitat degradation caused by landscape fragmentation led to a decline in biodiversity. The spatial distribution of habitat quality in the Beijing-Tianjin-Hebei region is closely correlated with topography and landscape, being higher in the northwest and lower in the southeast, forming a clear spatial pattern that declined from 0.599 to 0.564 between 1992 and 2032. The mean species richness (MSA) value of the Beijing-Tianjin-Hebei region is significantly affected by infrastructure, especially road construction. With the continuous expansion of the road network, the MSA values in the region generally show a decreasing trend from 0.270 to 0.183 between 1992 and 2032. Based on the above results, it is recommended to carry out several aspects of agrobiodiversity conservation and ecosystem restoration.

Population size and conservation status of large terrestrial mammals in a West African protected area

AbstractTerrestrial large mammals are threatened in West and Central Africa due to trade and consumption. The species population size was estimated using diurnal distance sampling in Old Oyo National Park, Nigeria. Mean species abundance and density ranged from 631 ± 281 to 3320 ± 1163 individuals and 2.0661 ± 1.356 to 6.7525 ± 3.0376 individuals km−2 between sub‐habitat types, and from 258 ± 125 to 2671 ± 867 individuals and 0.9526 ± 0.6801 to 5.1377 ± 1.8988 individual km−2 between the ranges. Based on IUCN guidelines for local assessment, we classified 1 species as Vulnerable, 10 Near Threatened and 1 Least Concern. Long‐term population monitoring and education programmes are crucial.

Bottom-up global biodiversity metrics needed for businesses to assess and manage their impact.

Ensuring that companies can assess and manage their impacts on biodiversity will be crucial to solving the current biodiversity crisis, and regulatory and public pressure to disclose these impacts is increasing. Top-down intactness metrics (e.g., Mean Species Abundance) can be valuable for generating high-level or first-tier assessments of impact risk but do not provide sufficient precision or guidance for companies, regulators, or third-party assessors. New metrics based on bottom-up assessments of biodiversity (e.g., the Species Threat Abatement and Restoration metric) can accommodate spatial variation of biodiversity and provide more specific guidance for actions to avoid, reduce, remediate, and compensate for impacts and to identify positive opportunities.

Effect of environmental drivers of fish assemblage and diversity patterns in temporal scale in Mongra Reservoir: A case study from one of the tributaries of Mahanadi Basin, Central India

AbstractInfluence of seasonal variations in environmental parameters on fish assemblage and species diversity patterns was studied in a tropical reservoir of Central India during March 2021 to February 2022. A total of 41 species belonging to 7 orders, 15 families and 29 genera were recorded with highest diversity during post‐monsoon season compared to the pre‐monsoon season and monsoon season. The fish abundance similarity between the monsoon and post‐monsoon reached a maximum of 89%. Seasonal variations in the mean species abundance, Simpson dominance index, Shannon diversity index, Pielou's evenness index and Margalef's richness index were determined. One‐way ANOVA revealed a significant difference (P < 0.05) at the temporal scale. There was a significant seasonal difference in species abundance (P = 0.0006) and evenness index (P = 0.02) among the diversity indices. During the study period, three ‘vulnerable’ species, three ‘near threatened’ species and two ‘endangered’ species were caught. Carnivore dominance was evident throughout the year in the trophic guild of fishes. The Pearson correlation test revealed that water pH, dissolved oxygen, sediment organic carbon and clay percentage were positively correlated to all four diversity indices. Simpson and Margalef species richness diversity indices were positively correlated to sediment pH. Fish abundance was positively associated with sediment pH, silt, phosphorus and nitrogen content. Canonical correspondence analysis was used to investigate the relationships between fish assemblages and environmental conditions. Among the 19 physicochemical parameters, nine (dissolved oxygen, total dissolved solids, conductivity, transparency, hardness, phosphate and chlorophyll‐a, sediment nitrogen and phosphorus) characteristics were shown to be statistically significant (P < 0.05) in determining fish diversity. Dissolved oxygen, total dissolved solids, conductivity, transparency, hardness, phosphate and chlorophyll‐a of water and sediment nitrogen and phosphorus qualities were the key factors for the species abundance. The reservoir boasts a diverse fish population that allows multi‐species fishing and generates revenue for numerous local fishers. Fish habitats should be protected in order to maintain diversity and long‐term ecological benefits.

Land use diversification may mitigate on-site land use impacts on mammal populations and assemblages.

Land use is a major cause of biodiversity decline worldwide. Agricultural and forestry diversification measures, such as the inclusion of natural elements or diversified crop types, may reduce impacts on biodiversity. However, the extent to which such measures may compensate for the negative impacts of land use remains unknown. To fill that gap, we synthesised data from 99 studies that recorded mammal populations or assemblages in natural reference sites and in cropland and forest plantations, with or without diversification measures. We quantified the responses to diversification measures based on individual species abundance, species richness and assemblage intactness as quantified by the mean species abundance indicator. In cropland with natural elements, mammal species abundance and richness were, on average, similar to natural conditions, while in cropland without natural elements they were reduced by 28% and 34%, respectively. We found that mammal species richness was comparable between diversified forest plantations and natural reference sites, and 32% lower in plantations without natural elements. In both cropland and plantations, assemblage intactness was reduced compared with natural reference conditions, but the reduction was smaller if diversification measures were in place. In addition, we found that responses to land use were modified by species traits and environmental context. While habitat specialist populations were reduced in cropland without diversification and in forest plantations, habitat generalists benefited. Furthermore, assemblages were impacted more by land use in tropical regions and landscapes containing a larger share of (semi)natural habitat compared with temperate regions and more converted landscapes. Given that mammal assemblage intactness is reduced also when diversification measures are in place, special attention should be directed to species that suffer from land use impacts. That said, our results suggest potential for reconciling land use and mammal conservation, provided that the diversification measures do not compromise yield.

Application of the CZ-Globio Model in Beskydy Protected Landscape Area

Abstract Spatially oriented simulation models have not yet been applied to the territory of Beskydy Protected Landscape Area (PLA) to assess the state of biodiversity at a local scale. The CZ-GLOBIO model, which is adapted to the conditions of the Czech Republic, was used as a tool to assess habitat degradation using four selected drivers. The aim of the article is to apply the CZ-GLOBIO model for biodiversity status assessment in Beskydy PLA at the biotope level using detailed habitat data. The result of the application of the model is the evaluation of the state of biodiversity and the risk of its degradation using the Mean Species Abundance (MSA) index. Values are obtained for each segment as well as the average value for the entire territory. The results of biodiversity modelling are available by five maps and five tables with output Mean Species Abundance (MSA) values. Understanding the spatial distribution of the resulting MSA values contributes to the landscape-level habitat assessment of Beskydy PLA. This can serve as a basis for further policy decisions in the environmental field.

Contaminant curiosity and pollutant puzzles: Conceptual insights in ecotoxicity and practical implementation of higher-tiered risk assessment.

Abstract Since the soil quality Tool for Risk Identification, Assessment and Display (TRIAD) approach introduced the “three lines of evidence” accounting for chemical, toxicological and ecological stressors to explain adverse effects in biota, the assessment of contaminant risks in the environment has significantly evolved. The concept of chemical speciation, related to water characteristics, boosted the understanding of the role of free-ion activities in the overall accumulation of pollutants in biota. New modeling concepts (e.g. biotic ligand models) and measuring techniques were developed. This in turn triggered widespread research addressing the quantitative role of sediment in the overall water quality, focusing on redox interfaces. For contaminant mixtures in river catchments, complex relations between (bio)availability of compounds, including nutrients, help to explain aquatic toxicity. Variation in ecological patterns and processes across environmental or spatiotemporal gradients occur, which may identify ecological factors that influence contaminant fate and effects. Empirical evidence by meta-analysis and theoretical underpinning by modelling showed relationships between population growth rates and carrying capacities, across chemicals and across species. The potentially affected fraction of species may be related to the mean species abundance, an often-used indicator in global change studies. Knowledge gaps remain on how pollutants travel through ecological communities and which species and species-relationships are affected. Outdoor experimental systems that examine the natural environment under controlled conditions may be useful at the higher biological level to investigate the impact of stressors on a variety of species, including mutual interactions.

Response of dung beetle diversity to remediation of soil ecosystems in the Ecuadorian Amazon.

Efforts to alleviate the negative effects of oil spills in the Ecuadorian Amazon include remediation activities such as cleaning, reshaping, and revegetation of polluted areas. However, studies of the diversity of biological communities in these hydrocarbon-degraded ecosystems have never been carried out. Here, we evaluated the diversity of dung beetles on remediated soil ecosystems (Agricultural Soils and Sensitive Ecosystems) and on non-contaminated soils (Natural Forests and Palm Plantations). The study was conducted in Sucumbíos and Orellana provinces, in the Ecuadorian Amazon at four sampling sites per ecosystem type (a total of 16 sites). At each sampling site, six pitfall traps remained active for 120 consecutive h per month for 1 year. We collected 37 species and 7,506 individuals of dung beetles. We observed significant differences in mean species abundance, richness, and diversity between non-contaminated soil ecosystems and remediated soil ecosystems, with Natural Forests presenting the highest values, and Agricultural Soils the lowest values. Regarding sampling month, we also found significant differences among ecosystems, which were also higher in Natural Forests. The results suggest that hydrocarbon-degraded ecosystems tend to conserve lower beetle diversity one year after remediation highlighting the importance of Natural Forests for the conservation of tropical biodiversity. Therefore, dung beetle diversity could be used for future landscape management of these hydrocarbon-degraded ecosystems.

Multilevel driving factors affecting ecosystem services and biodiversity dynamics on the Qinghai-Tibet Plateau

Understanding the driving factors of ecosystem services and biodiversity (ESB) is necessary for sustainable ecosystem management. Previous studies have analyzed many individual factors affecting ESB on the Qinghai-Tibet Plateau (QTP). However, there is limited knowledge on the scale dependence of the driving factors at different levels. In this study, we selected and assessed vegetation carbon uptake reduction (VCR), water supply index (WSI), and mean species abundance (MSA) on the QTP during 2000–2020, which can represent carbon sequestration, water yield ecosystem services, and biodiversity intactness, respectively. Then, we unutilized the hierarchical linear model (HLM) to determine the impacts of natural factors at the eco-functional zone level and socioeconomic factors at the city level on the three indices. The results showed that the spatial distribution of VCR and WSI had a generally gradual declining trend, and MSA had an increasing trend from the southeast to the northwest from 2000 to 2020. At the eco-functional zone level, degradation of forest and grassland had the greatest, most negative effects on carbon uptake and MSA. Potential evapotranspiration rather than precipitation had the strongest and most positive influence on the WSI. At the city scale, rural per capita net income, GDP, and meat production dominated the decrease in VCR, WSI, and MSA, respectively. The eco-functional zone was nested into the city, population, and economic controlled ESB mainly through its effect on land use, especially grassland. VCR and MSA were mainly affected by natural factors, while WSI was affected by socioeconomic factors. Overall, our study provides a reference for analyzing the multilevel factors that affect the sustainability of ESB.

The impact of imidacloprid and thiacloprid on the mean species abundance in aquatic ecosystems

Neonicotinoids are currently the most widely used and sold insecticides in the world, providing effective pest control. Risk assessment of these and other pesticides by lab-based indicators is common. Yet, empirically and theoretically underpinning of extrapolation to indicators used in field surveys is severely limited. Consequently, the aim of our study was to quantify the toxicological and ecological impact of the neonicotinoids imidacloprid and thiacloprid to aquatic invertebrates. We derived Species Sensitivity Distributions (SSDs) based on chronic LC50 data and Mean Species Abundance Relationships (MSARs), comparing these lab-based approaches to field data as well. MSARs are changes in mean species abundance (MSA) as a function of chemical exposure, providing insight into the overall decline of a community. The MSA expresses the mean abundance of species in disturbed conditions relative to their abundance in undisturbed habitat. The medians of the SSD of imidacloprid and thiacloprid for the different species were 16.45 μg/L and 26.40 μg/L, respectively. HC50s of the MSAR of imidacloprid and thiacloprid were 4.25 μg/L and 5.12 μg/L, respectively. The three taxonomic groups tested (insects, crustaceans and mollusks) did not differ significantly in sensitivity for imidacloprid and thiacloprid, both according to the SSDs and MSARs derived. Quantile exposure-response curves (99%-tile) were plotted showing the relative abundance (RA) of aquatic invertebrate species at increasing imidacloprid levels. The 99%-tile of the Relative Abundances (RA99) of species and corresponding imidacloprid concentrations monitored in field surveys in the Netherlands was significantly lower than the Potentially Affected Fraction (PAF) calculated from the SSD. Yet, the MSA was similar to the RA99, suggesting that MSAR is an ecologically meaningful relationship for toxic stress estimated from lab data. Future efforts should be directed to additional empirical underpinning as well as determining the relationship of PAF to other metrics for ecosystem diversity and productivity.

All shallow coastal habitats matter as nurseries for Mediterranean juvenile fish

Coastal zones are ecosystems of high economic value but exposed to numerous disturbances, while they represent nurseries for many fish species, raising the issue of the preservation of their functions and services. In this context, the juvenile fish assemblages of all types of habitats present in shallow coastal zones were studied on the south-east coast of France using underwater visual censuses in warm (June–July 2014) and cold (April 2015) periods. A total of fourteen habitat types were characterized, which could be grouped into three broad categories, rocky substrates (natural and artificial), sedimentary bottoms with all levels of granulometry, and seagrass beds including Cymodocea nodosa and Posidonia oceanica meadows; the ecotones or interfaces between the three broad habitat categories were individualized as particular habitat types. The abiotic and biotic descriptors of the 14 habitat types individualized did not vary with time, except for a higher cover percentage and canopy height of macrophytes in the warm period, which increased the three-dimensional structure of some habitats. The taxonomic composition and density of juvenile fish assemblages were analyzed using both multivariate and univariate descriptors, after grouping the 57 fish species recorded into 41 well-individualized taxa. Juvenile fishes were recorded in all habitat types, with higher mean species richness and abundance during the warm than the cold period. The richest habitats in terms of both fish species richness and abundance were the natural rocky substrates and the interfaces between Posidonia beds and the other habitats. Although juvenile fish assemblage composition differed among habitat types and between periods, the most abundant fish species were Atherina sp., Sarpa salpa, Gobiidae, Symphodus spp., Pagellus spp. and several Diplodus species, which colonized 7 up to 14 different habitat types (depending on taxa) during their juvenile life. Most species settled in one or a few specific habitats but rapidly colonized adjacent habitats when growing. This study provided evidence of the role of all types of shallow coastal habitats as fish nurseries and their varying pattern of occupation in space and time by the different juvenile stages. It highlighted the importance of the mosaic of habitats and interfaces for the complete development of all juvenile life stages of fishes, and for the preservation of a high diversity of coastal fish assemblages and fisheries resources in the Mediterranean Sea.

Assessing Habitat Vulnerability and Loss of Naturalness: Applying the GLOBIO3 Model in the Czech Republic

Global and regional biodiversity loss is caused by several drivers including urban development, land use intensification, overexploitation of natural resources, environmental pollution, and climate change. The main aim of our study was to adapt the GLOBIO3 model to the conditions of the Czech Republic (CR) to assess loss of naturalness and biodiversity vulnerability at the habitat level on a detailed scale across the entire CR. An additional aim was to assess the main drivers affecting the biodiversity of habitat types. The GLOBIO3 model was adapted to CZ-GLOBIO by adapting global to local scales and using habitat quality and naturalness data instead of species occurrence data. The total mean species abundance (MSA) index of habitat quality, calculated from the spatial overlay of the four MSA indicators by our new equation, reached the value 0.62. The total value of MSA for natural and near-natural habitats was found to be affected mainly by infrastructure development and fragmentation. Simultaneously, intensity of land use change and atmospheric nitrogen deposition contributed primarily to the low total value of MSA for distant natural habitats. The CZ-GLOBIO model can be an important tool in political decision making to reduce the impact of the main drivers on habitat biodiversity in the CR.

Realised rather than fundamental thermal niches predict site occupancy: Implications for climate change forecasting.

Thermal performance traits are regularly used to make forecasts of the responses of ectotherms to anthropogenic environmental change, but such forecasts do not always differentiate between fundamental and realised thermal niches. Here we determine the relative extents to which variation in the fundamental and realised thermal niches accounts for current variation in species abundance and occupancy and assess the effects of niche-choice on future-climate response estimations. We investigated microclimate and macroclimate temperatures alongside abundance, occupancy, critical thermal limits and foraging activity of 52 ant species (accounting for >95% individuals collected) from a regional assemblage from across the Western Cape Province, South Africa, between 2003 and 2014. Capability of a species to occupy sites experiencing the most extreme temperatures, coupled with breadth of realised niche, explained most deviance in occupancy (up to 75%), while foraging temperature range and body mass explained up to 50.5% of observed variation in mean species abundance. When realised niches are used to forecast responses to climate change, large positive and negative effects among species are predicted under future conditions, in contrast to the forecasts of minimal impacts on all species that are indicated by fundamental niche predictions.

Mean Species Abundance as a Measure of Ecotoxicological Risk.

Chemical pollution of surface waters is considered an important driver for recent declines in biodiversity. Species sensitivity distributions (SSDs) are commonly used to evaluate the ecological risks of chemical exposure, accounting for variation in interspecies sensitivity. However, SSDs do not reflect the effects of chemical exposure on species abundance, considered an important endpoint in biological conservation. Although complex population modeling approaches lack practical applicability when it comes to the routine practice of lower tier chemical risk assessment, in the present study we show how information from widely available laboratory toxicity tests can be used to derive the change in mean species abundance (MSA) as a function of chemical exposure. These exposure–response MSA relationships combine insights into intraspecies exposure–response relationships and population growth theory. We showcase the practical applicability of our method for cadmium, copper, and zinc, and include a quantification of the associated statistical uncertainty. For all 3 metals, we found that concentrations hazardous for 5% of the species (HC5s) based on MSA relationships are systematically higher than SSD‐based HC5 values. Our proposed framework can be useful to derive abundance‐based ecological protective criteria for chemical exposure, and creates the opportunity to assess abundance impacts of chemical exposure in the context of various other anthropogenic stressors. Environ Toxicol Chem 2020;39:2304–2313. © 2020 The Authors. Environmental Toxicology and Chemistry published by Wiley Periodicals LLC on behalf of SETAC.

Species-abundance distributions and Taylor’s power law of fluctuation scaling

Two widely investigated areas of theory in ecology over the past half century are species-abundance distributions (SADs) and Taylor’s power law of fluctuation scaling (TL). This paper connects TL with a classic SAD, MacArthur’s broken-stick model. Each of these models is more than 60 years old, but apparently the connection has not been observed previously. For large numbers of species, the broken-stick model asymptotically obeys TL with exponent 2: the variance of species abundance equals the square of the mean species abundance. Equivalently, in the broken-stick model, the coefficient of variation of abundance is asymptotically 1. Because both the broken-stick model and TL have interpretations and applications beyond ecology, the connection established here has broader than purely ecological interest. This simple but previously unnoticed relationship between the broken-stick model and the power-law variance function raises the question of how other species-abundance distributions are related to power law or other variance functions.

Potential biodiversity change in Central Asian grasslands: scenarios for the impact of climate and land-use change

Central Asian grasslands are extensively used for pastoral livestock grazing. This traditional land use is nowadays characterized by intensifying grasslands into more productive pastures. This change affects biodiversity and diminishes grasslands’ ecological role. Biodiversity impacts are probably also exacerbated by climate change. These changes in biodiversity are poorly studied in Central Asia. Here, we estimated potential biodiversity changes in the Central Asian grasslands using the latest shared socio-economic pathways and the representative concentration pathways (i.e., SSP-RCP scenario framework). We selected scenarios with contrasting socio-economic and climate conditions (i.e., SSP1-RCP4.5, SSP3-RCP8.5, SSP4-RCP4.5, and SSP5-RCP8.5) and further detailed the land-use scenarios for the region using stakeholders’ input. We indicated future biodiversity by the mean species abundance indicator. The contrasting scenario combinations showed that grasslands’ biodiversity will decline under each scenario. The strongest impact on biodiversity is expected in SSP5-RCP8.5, where half of the grasslands are likely to lose most of their local originally occurring species by 2100. The lowest impact is expected in SSP4-RCP4.5. Our study stresses the potential vulnerability of this region to increasing land-use intensity and climate change. These impact projections can help regional decision makers to develop and implement better biodiversity-conservation and sustainable management policies for these grasslands.

Temporal changes in bird communities of wind-affected coniferous mountain forest in differently disturbed stands (High Tatra Mts., Slovakia)

In November 2004 a large windstorm affected forests dominated by Norway spruce (Picea abies (L.) H. Karst, 1881) in the High Tatras National Park, Slovakia, and was followed by a wildfire (2005) and bark beetle outbreak. In this study we investigate temporal changes of breeding bird community (their species richness, density and diversity) as well as different nest-position guilds, in relation to disturbance type. Bird species composition was surveyed in two periods (2006 and 2007, and 2017 and 2018) using the point count method on four plots differing by disturbance type – undisturbed forest, unlogged windthrow, salvage logged windthrow and burnt salvage logged windthrow. A total of three visits per point and breeding season were performed at forty point count sites. We also assessed the successional shift in habitat characteristics between the two monitored periods. In total, 55 bird species and 2059 individuals were recorded on the plots during the study. We observed no effect of disturbance type on mean species richness, abundance and Simpson’s diversity per point; however, those characteristics did significantly increase over the study duration. While differently disturbed points had previously differed in their (nest-position) guild number and diversity, the differences between them disappeared over time. We found different trajectories of temporal change in the composition of the species communities and guild diversity in relation to disturbance type, but in a similar direction. During the first period, the greater the initial differences in the severity of disturbance among the disturbance types, the greater the differences were in the composition of bird communities; however, the differences gradually diminished as the forests regenerated. Alterations in habitat structure caused by natural and anthropogenic disturbance and by subsequent succession were the most probable reasons for the altered bird communities and observed patterns of recovery.

Assessing land-based mitigation implications for biodiversity

The Paris Agreement to keep global temperature increase to well-below 2 °C and to pursue efforts to limit it to 1.5 °C requires to formulate ambitious climate-change mitigation scenarios to reduce CO2 emissions and to enhance carbon sequestration. These scenarios likely require significant land-use change. Failing to mitigate climate change will result in an unprecedented warming with significant biodiversity loss. The mitigation potential on land is high. However, how land-based mitigation options potentially affect biodiversity is poorly understood. Some land-based mitigation options could also counter the biodiversity loss. Here we reviewed the recently scientific literature to assess twenty land-based mitigation options that are implemented in different mitigation pathways to comply with the Paris Agreement for their biodiversity impacts by using the Mean Species Abundance (MSALU) indicator for land use. We showed the likely land-use transition and potential MSALU changes for each option, compared their carbon sequestration opportunities (tC per ha) and assessed the resulting biodiversity change in two case scenarios. Our results showed that most options benefit biodiversity. Reforestation of cultivated and managed areas together with restoration of wetlands deliver the largest MSALU increases, if land is allowed to reach a mature state over time. A quarter of the assessed options, including intensification of agricultural areas and bioenergy with carbon capture and storage, decreased MSALU. Options, such as afforestation and reduced deforestation, either positively or negatively affected MSALU. This depends on their local implementation and adopted forest-conservation schemes. Comparing the different options showed that avoiding deforestation by implementing agroforestry at the expense of pastures delivered both the largest MSALU increases and the highest carbon sequestration opportunities. However, agroforestry that leads to deforestation, enhanced carbon sequestration slightly but with a marginal MSALU increase. This stresses the importance of avoiding forest conversion. Our study advances the understanding on current and future benefits and adverse effects of land-based mitigation options on biodiversity. This certainly helps biodiversity conservation and determines the regions with large land-based mitigation potential.

Response of Understory Bird Feeding Groups to Deforestation Gradient in a Tropical Rainforest of Cameroon

Birds are crucial in maintaining the balance of many ecosystems and provide various ecological services. Understanding their sensitivity to human disturbances should be prioritized in understudy areas for effective conservation practices. Using mist nets, this study characterized mostly understory bird communities (insectivorous, frugivorous, granivorous, and nectarivorous birds) in three habitat types (pristine forest, selectively logged forest, and young oil palm plantation) in the Talangaye rainforest, Southwest Cameroon. A total of 845 birds belonging to 27 families and 85 species were recorded in the three habitats after 294 h of mist netting. Overall, the mist-netted community was largely dominated by insectivores, followed by frugivores, nectarivores, granivores, and carnivores. Although mean species richness, abundance, and Simpson diversity index did not vary significantly among habitat types, mean species abundance and diversity index decreased in selectively logged forest and young oil palm plantation and species richness increased in both habitats. The species richness, abundance, and diversity index for insectivorous and frugivorous birds were lowest in the young oil palm plantations. For granivores, species richness and abundance increased following selective logging and the establishment of oil palm plantation. The highest mean species richness and diversity index in nectarivores were recorded in the young oil palm plantations. The study showed that selective logging and establishment of oil palm plantation had variable effects on the bird communities in the Talangaye rainforest. Also, the frugivorous birds appeared to be more sensitive to both types of disturbances, while the insectivores were more sensitive to habitat loss/conversion.