Effects Of Environmental Change Research Articles

Econometrics of Climate Change Research

The econometrics of climate change explores the intricate interplay between economic activity and climate dynamics, offering empirical insights into the causes, impacts, and mitigation of global climate change. This research applies advanced econometric techniques to quantify the economic consequences of environmental changes and evaluate the effectiveness of climate policies. By leveraging panel data models, time-series analysis, and causal inference methods, this study investigates critical topics such as the economic costs of extreme weather events, the efficacy of carbon pricing mechanisms, and the role of renewable energy adoption in mitigating climate risks. Additionally, this research incorporates machine learning techniques to enhance predictive accuracy in modeling future climate-economic interactions. Through rigorous empirical analysis, the study provides actionable recommendations for policymakers to design sustainable strategies that balance economic growth with climate resilience. The findings contribute to a deeper understanding of the socioeconomic dimensions of climate change, emphasizing the importance of evidence-based decision-making in addressing one of humanity’s most pressing challenges.

From lake to fisheries: Interactive effect of climate and landuse changes hit on lake fish catch?

Global warming and unpredictable nature possess a negative impact on fisheries and the daily activities of other habitats. GIS and remote sensing approach is an effective tool to determine the morphological characteristics of the lake. The present study addresses the interactive effect of climate and landuse changes hit on fish catch in lake fisheries. We used a combination of the landscape disturbance index, vulnerability index, and loss index to construct a complete ecological risk assessment framework based on the landscape structure of regional ecosystems. The results indicate an increase from around 45%–76% in the percentage of land susceptible to moderate to ecological severe risk in the landscape from 2004 to 2023. Since 1950, temperature changes have increased by 0.4%, precipitation has decreased by 6%, and water levels have decreased by 4.2%, based on the results. The results indicate that landuse, water temperature, precipitation, and water depth significantly impact the aquaculture system. The findings strongly suggest integrating possible consequences of environmental change on fish yield for governance modeling techniques to minimize their effects.

Innovative Solutions to Environmental Challenges: Exploring Fishermen's Perspectives on Technology-driven Conservation Efforts in Noveleta, Cavite

This phenomenological study explores the viewpoints of fishermen in Noveleta, Cavite, on technology-based conservation initiatives and their effects on local marine ecosystems and fishing methods. Using purposive sampling, seven participants offered valuable insights into the present condition of marine life, the implementation of cutting-edge solutions, and the impact of these technologies on their means of living. The study revealed several themes: The challenges of modern fishing conditions, including stricter laws, and the consequences of environmental changes, such as pollution and habitat damage. Fishermen also discussed how government rules impacted them and how new technologies like GPS and fish finders brought new challenges even as productivity rose. Furthermore, the discussion underscored significant concerns such as the necessity for efficient marine conservation, the impact of infrastructure developments on local communities compared to traditional practices, and the economic viability amidst shifting circumstances. This study highlights the complex connection between policy, technology, and traditional fishing methods, highlighting the importance of inclusive and sustainable approaches to conservation.

Combined cadmium and chromium isotopes record a collapse of bioproductivity across the Cretaceous—Paleogene boundary in the Danish basin

Cadmium (Cd) isotope signatures (δ114Cd) deduced from modern and ancient marine deposits are often used as a proxy for bioproductivity and for micronutrient cycling, whereas chromium (Cr) isotope signatures (δ53Cr) are used as a potential proxy for oxygenation. The Cretaceous—Paleogene (K/Pg) boundary records one of Earth's five big mass extinctions, which contains geochemical fingerprints of the Chixculub asteroid impact and is coeval with the Deccan Trap volcanism. Here we present for the first time a combined record of Cd and Cr isotopes from the Danish Basin to interrogate the effects on bioproductivity across the K/Pg boundary. The δ114Cd values range between −0.28‰ and 0.27‰ defining an average of 0.05‰ ± 0.24 (2σ, n = 87). Authigenic δ53Cr values range between 0.06‰ and 1.06‰ and define an average of 0.59‰ ± 0.51 (2σ, n = 81). An abrupt jump, across the K/Pg boundary layer, from consistently positively fractionated Cd and Cr isotope signatures recorded in Late Maastrichtian white chalks towards less positively fractionated δ114Cd values and heterogeneous δ53Cr values in the Early Danian carbonates, likely indicates a decrease in surface water bioproductivity. This decrease is accompanied by redox fluctuations in the water column as a consequence of environmental changes either related to the Chixculub impact event and/or to the Deccan volcanic eruptions coeval with this boundary. Assuming an efficient removal of Cd and Cr through consumption and/or adsorption by primary producers, or by incorporation into the skeleton/shells of calcifiers, and using the fractionation factor of Cd into carbonates, we reconstruct surface water conditions during the Late Masstrichtian—Early Danian that are compatible with those of modern oceans, with δ114Cd varying from 0.17 to 0.72‰. Overall, the combined Cr-Cd isotope fluctuations over the K/Pg boundary are consistent with a scenario characterized by climate-induced changes of nutrient availability and concomitant responses of primary production levels, ultimately related to the asteroid impact and to the proceeding volcanic activities that influenced the ocean's chemistry. We anticipate our results to point for further studies of other stratigraphic sections worldwide to reveal an extensive Cd-Cr record for the Cretaceous—Paleogene boundary and its corresponding collapse of bioproductivity and decreasing ocean oxygenation.

Ecological traits predict population trends of urban birds in Europe

The population dynamics of urban animals has been so far remarkably understudied. At the same time, urban species’ population trends can provide important information on the consequences of environmental changes in cities. We modelled long-term population trends of 93 bird species breeding in urban areas in 16 European countries as a function of species’ traits, characterising variability in their urbanization and ecology. We found that: (i) earlier colonisers have more negative population trends than recent colonisers; (ii) more urbanized open habitat species had more positive population trends than less urbanized open habitat species; (iii) highly urbanized birds breeding above the ground had more negative trends than highly urbanized ground breeders. These patterns can be explained by several processes occurring in cities as well as outside city borders. Namely, (i) pre-industrial colonisers might struggle to persist in rapidly changing urban areas, limiting their foraging and breeding opportunities of the birds. (ii) Open habitats are under pressure of intensive agricultural exploitation in rural areas, which may negatively affect populations of less urbanized birds. In contrast, urban areas do not experience such pressure keeping the trends of urbanized open habitat species more positive. (iii) Differences in population trends between highly urbanized ground and above-ground breeders suggest that the latter may lose their breeding opportunities in modern buildings that do not provide suitable breeding sites. Our results indicate that even once successful, city dwellers may not keep pace with changes in urban areas, but these areas may also provide suitable habitats for biodiversity.

The Strategic Renewal Model of Organizations Under Environmental Uncertainty (Case Study: Startup Organizations in the Payment Industry)

The concept of strategy is intertwined with environmental uncertainty. In fact, strategic management can be seen as a systematic approach to dealing with environmental turbulence and changes, ultimately ensuring business success and preventing the negative consequences of environmental changes in business. Therefore, many researchers and managers seek solutions to reduce the impact of uncertainty in order to make effective strategic decisions. Among the various methods that managers choose to manage environmental uncertainty, strategic renewal is considered one of the most effective approaches. Some businesses, such as payment startups, face greater environmental uncertainties due to the nascent nature of the industry on one hand and the nascent state of the organization on the other. The strategic management literature does not provide a comprehensive solution for the strategic renewal of nascent businesses. Hence, this study, using the case study research method and focusing on an active startup in the payment industry, aims to propose a model for the strategic renewal of payment startups operating in environments with high uncertainty. This research revealed that among environmental factors, certain factors lead to increased environmental uncertainty for startup businesses. Additionally, in this model, the components of the strategic renewal process, as well as the outcomes and consequences of implementing strategic renewal in these businesses, have been identified.

Simulation model for predicting ecological condition of urban areas at traffic intersections

This article substantiates the relevance of the development and use of digital tools that allow modeling objects and processes of transport systems to determine the environmental consequences of changes in their quantities and states. The use of methods of structural analysis, systematization, observation, statistical analysis of data allowed to establish all key objects of the system and their qualitative and quantitative indicators necessary to create a digital twin. The use of simulation modeling methods allowed to formalize the obtained results into models involved in the digital twin of the transport system. Using the graphical method, state diagrams were developed to demonstrate the transition of states of each object of the process depending on changes in environmental conditions. On the basis of the statistical analysis of pollutant emissions in the study area, a parametric model was developed for each pollutant factor.

Solastalgia mediates between bushfire impact and mental health outcomes: A study of Australia's 2019–2020 bushfire season

In 2019–2020, Australia experienced an unprecedented bushfire season that caused widespread environmental destruction across the continent, and especially to its south-east corner. Over two studies, we examine mental health outcomes of individuals impacted by bushfire, drawing on the concept of solastalgia – the sense of distress arising from unwanted environmental change – as a potential explanation for the mental health consequences of bushfire. In Study 1, we surveyed 2084 residents from the Australian Capital Territory and surrounding regions directly after the bushfire season. Participants were asked about exposure to the 2019–2020 bushfires, and to a previous regional fire of significance, experience of solastalgia, and five mental health indicators. In Study 2, we broaden our focus to all of Australia, and administer our measures with a nationally representative sample six months after the conclusion of the bushfire season (N = 1477). In both studies, we find the severity of reported bushfire impact is significantly associated with mental health, such that greater impact predicts poorer outcomes. Moreover, we find the experience of solastalgia mediates the relationship between bushfire impact and mental health and wellbeing. Experiencing solastalgia is a partial, but important, mechanism for understanding the impact of bushfire exposure on mental health and wellbeing. Importantly, people not directly impacted by a bushfire event also experience solastalgia and subsequent poorer mental health outcomes following bushfires. We suggest that future measurements of the impact of abrupt environmental change events, including bushfires, consider the role of solastalgia and localised environmental contexts in shaping the mental health impacts to the population.

Unravelling the influence of annual weather conditions and Mediterranean habitat types on acorn production, availability and predation

Seed production and survival are critical steps in the life cycle of plants, and could become bottlenecks for plant regeneration in case of failure. During regeneration many factors, both abiotic and biotic, intervene and interact with each other. After dispersal, environmental variation affects the success of the plant population, so seedling recruitment can display spatial variability. However, few studies of seed production and availability cover a range of habitat conditions (e.g. mature, transitional and post-fire habitats), which makes it difficult to evaluate the potential of site-production relationships. We study how the heterogeneity of habitat structure and composition affects the phenology, production and availability of acorns, mainly holm oak, in a Mediterranean Natural Park. Our results show that meteorological variables determine the phenology of acorn fall. Habitat types present temporal mismatches in falls since, for example, shrublands required a longer period of time for all seeds to fall. Furthermore, habitats with greater tree density and low understory complexity had higher production but smaller acorns. Lower densities promote higher acorn volume (seedling size) as a consequence of less intraspecific competition and more reserves for germination. The proportion of viable acorns available on the ground also decreased substantially in winter, when the proportion of infested acorns increase because the selective consumption of sound acorns by predators. Acorns from mixed forests and shrublands had less pre-dispersal predation by arthropods and post-dispersal predation by wild boar as a result of oak isolation and understory complexity. Conversely, rodents are more abundant in shrublands, where they find a greater diversity of anti-predator refuges and large nutritious acorns available in autumn and winter. Understanding the reproductive constraints imposed by time and space allows us to infer the consequences of environmental changes on population recruitment and persistence. We thus show that habitats with a high density of oak trees, less plant diversity and understory cover had a greater prevalence of infested acorns, thereby reducing recruitment viability. These habitats also had more available acorns on the ground for seed predators. Therefore, habitat type is an important factor affecting acorn production and should be taken into account in future studies.

Global leaf‐trait mapping based on optimality theory

AbstractAimLeaf traits are central to plant function, and key variables in ecosystem models. However recently published global trait maps, made by applying statistical or machine‐learning techniques to large compilations of trait and environmental data, differ substantially from one another. This paper aims to demonstrate the potential of an alternative approach, based on eco‐evolutionary optimality theory, to yield predictions of spatio‐temporal patterns in leaf traits that can be independently evaluated.InnovationGlobal patterns of community‐mean specific leaf area (SLA) and photosynthetic capacity (Vcmax) are predicted from climate via existing optimality models. Then leaf nitrogen per unit area (Narea) and mass (Nmass) are inferred using their (previously derived) empirical relationships to SLA and Vcmax. Trait data are thus reserved for testing model predictions across sites. Temporal trends can also be predicted, as consequences of environmental change, and compared to those inferred from leaf‐level measurements and/or remote‐sensing methods, which are an increasingly important source of information on spatio‐temporal variation in plant traits.Main conclusionsModel predictions evaluated against site‐mean trait data from > 2,000 sites in the Plant Trait database yielded R2 = 73% for SLA, 38% for Nmass and 28% for Narea. Declining species‐level Nmass, and increasing community‐level SLA, have both been recently reported and were both correctly predicted. Leaf‐trait mapping via optimality theory holds promise for macroecological applications, including an improved understanding of community leaf‐trait responses to environmental change.

Youth visions in a changing climate: Emerging lessons from using immersive and arts-based methods for strengthening community-engaged research with urban youth


 
 
 Despite increasing efforts, youth perspectives remain largely excluded from decision- making processes concerning their future and the social-ecological challenges they are set to inherit. While youth are a critical and powerful force for social change, many youths in underserved communities have limited access to appropriate information on the root causes and consequences of environmental change, in addition to an array of other complex social injustices. To address this, we embarked on a participatory action research process which focused on democratising research, science and the arts by facilitating experiential, immersive learning opportunities with the intention of eventually co-producing artifacts (in the form of participatory murals) in public spaces to facilitate longer term engagement with human nature futures. This article outlines and shares reflections on our process and offers insights for future engagement activities that seek to mobilise youth imaginaries and agency. We found participants were better engaged when conversations were (1) facilitated by other participants; (2) were outdoors and centred on public art; and (3) were happening in parallel with a hands-on activity. This contrasted with asking interview-type questions, or asking participants to write down their answers, which felt more like a test than a conversation, minimising participation. Key learnings included: the need to co-develop knowledge around enhancing climate literacy that is based on local realities; that multiple capacities and hives of activity already exist in communities and need to be mobilised and not built; that creative visioning and futuring can help identify options for change; and that many youths are seeking creative, immersive and safe spaces for co-learning and connection. Initiatives that aim to engage diverse voices should therefore be well- resourced so as to carefully co-design processes that start by acknowledging contextual differences and capacities within those contexts, and co-create immersive dialogues, in order to move away from test-like engagements which perpetuate power imbalances and discourage participation.
 
 

Hydrochemical and isotopic baselines for understanding hydrological processes across Macquarie Island.

Isotopic and hydrochemical data from lakes provide direct information on catchment response to changing rainfall, evaporation, nutrient cycling, and the health of ecosystems. These techniques have not been widely applied to lakes in the Southern Hemisphere high latitudes, including Southern Ocean Islands (SOIs) experiencing rapid, significant shifts in climate. Historical work has highlighted the localised nature of geochemical drivers in controlling the hydrochemical evolution of lakes, such as geology, sea spray contribution, vegetation, geographical location, and ice cover extent. The role of groundwater in lake hydrology and hydrochemistry has not been identified until now, and its omission will have major implications for interpreting soil-water-air processes affecting lakes. Here we present the first comprehensive, island-wide hydrochemical and isotopic survey of lakes on a SOI. Forty lakes were examined across Macquarie Island, using comparable methods to identify key environmental processes and their geochemical drivers. Methods include stable carbon (δ13CDOC: dissolved organic carbon and δ13CDIC: dissolved inorganic carbon), oxygen (δ18O), hydrogen (δ2H) and strontium isotopic ratios (87Sr/86Sr) in water. These provide essential baseline data for hydrological, biological, and geochemical lake processes. Lakes on the western side of the island are influenced by sea spray aerosols. In general, it was found that lakes at higher elevations are dilute and those located in lower elevation catchments have experienced more water-rock interactions. The hydrochemical and isotopic tracers suggest that lakes in lower elevations contain more terrestrial sourced ions that may be contributed from groundwater. Increasing temperatures and changing rainfall patterns predicted for the region will lead to shifts in nutrient cycles, and impact the island's unique ecosystems. Future research will focus on long-term monitoring to understand seasonal, annual, and long-term variability to test fundamental hypotheses concerning ecosystem function and the consequences of environmental change on SOIs.

Light-driven processes: key players of the functional biodiversity in microalgae.

Microalgae are prominent aquatic organisms, responsible for about half of the photosynthetic activity on Earth. Over the past two decades, breakthroughs in genomics and ecosystem biology, as well as the development of genetic resources in model species, have redrawn the boundaries of our knowledge on the relevance of these microbes in global ecosystems. However, considering their vast biodiversity and complex evolutionary history, our comprehension of algal biology remains limited. As algae rely on light, both as their main source of energy and for information about their environment, we focus here on photosynthesis, photoperception, and chloroplast biogenesis in the green alga Chlamydomonas reinhardtii and marine diatoms. We describe how the studies of light-driven processes are key to assessing functional biodiversity in evolutionary distant microalgae. We also emphasize that integration of laboratory and environmental studies, and dialogues between different scientific communities are both timely and essential to understand the life of phototrophs in complex ecosystems and to properly assess the consequences of environmental changes on aquatic environments globally.

Integrating Indigenous and scientific perspectives on environmental changes: Insights from boreal landscapes

Abstract Major environmental changes affect the health and capacity of ecosystems to sustain Indigenous people's well‐being in boreal landscapes. Collaboration between Indigenous communities and researchers could help assessing and mitigating the consequences of environmental changes. We used Driver Pressure State Impact (DPSI) conceptual models to compare the perspectives of Indigenous and scientific communities on environmental changes in boreal landscapes of Quebec, Canada. The Indigenous DPSI model emerged from interviews with local land‐use experts from two Indigenous communities. The scientific model was informed by the publication topics of expert researchers. We compared the Indigenous and scientific models and exposed convergences and divergences between perspectives. Forestry was identified as a major driver of change in both models. Most issues related to mining, hydro‐power and forest road development were specific to the Indigenous model. Climate change and wildfires were of greater interest in the scientific model. Convergences between the perspectives of Indigenous and scientific communities are conducive to collaborative research. Divergences could be addressed through reciprocal knowledge transfer activities, which would lead to research that better aligns with the concerns and needs of Indigenous communities. Read the free Plain Language Summary for this article on the Journal blog.

Consequence of Environmental Change on the Animal’s Health and Productivity: A Brief Review

The effects of climate change, especially global warming, can greatly affect the production performance and health of animals around the world. The national average temperature has increased by 1°C since 1970. Most livestock owners in the country feel that weather change is affecting farm animal production and health. The main impacts of weather change on animal production include feed shortages, water shortages, reduced livestock genomic resources, decreased productivity, and reduced mature weight and/or longer time to reach mature weight based on their significance. High temperatures resulting from environmental alteration may increase the level of development of few pathogens or parasites that found one or more life cycle levels outside the mammalian host. Besides, the spatial disposition and visibility of pasture and water are largely depending on the pattern and visibility of rainfall. Food and water shortages bestow to deduced livestock abundance and reproductive execution. These include slow growth rate of animals, loss of body condition, decreased milk yield, and poor reproductive performance of mature animals. Drought bulls that are debilitated and in poor physical condition cannot provide sufficient drought energy for plowing and thus hinder crop cultivation. Bush encroachment, as well as population pressure, leads to reduced availability of good pastures thus environmental change will have far-reaching consequences for animal yield and health, especially in vulnerable parts of nature where it is essential for nutrients and maintenance. Once more, the environmental change affects farm animal health through various mechanisms; which are effects on parasites, effects on hosts, and vectors, such as alters in precipitation and temperature schemes that can influence both the placement and ample of disease careers; and effects on micropaleontology, such as alteration of transmission levels between hosts. This study has focused to investigate the inherent impacts of environmental alteration on livestock health and productivity.

Re‐surveys reveal biotic homogenization of Orthoptera assemblages as a consequence of environmental change

AbstractAimBiodiversity loss is a major global challenge. While population trends of vertebrates are well documented, insect declines have not been sufficiently studied. We aim to identify changes in Orthoptera assemblages and the underlying drivers with a focus on land‐use and climate change.LocationCentral Europe.Time period2018 to 2020.MethodsWe resurveyed 199 study sites in which Orthoptera assemblages had been recorded between 1986 and 1999.ResultsOur results show a significant increase in species per site (α‐diversity), but simultaneously a homogenization of Orthoptera assemblages (decreasing Sorensen's β‐diversity). Highly mobile species significantly increased in site occupancy compared to species with low mobility. Some Orthoptera species showed significant altitudinal range shifts, including species with positive trends (i.e. expansion to higher altitudes) and negative trends (i.e. extinction at lower altitudes). Abandonment of extensively used grassland sites and the associated afforestation had negative effects on Orthoptera, underlining the importance of extensive grassland management. Protected areas had a high efficacy for conservation as trends in site occupancy were generally more positive in protected areas than in unprotected sites.Main conclusionsOur results provide insights into the patterns and drivers of orthopteran assemblage turnover, including major effects of agricultural land‐use change and climate change. These results are essential for implementing and adapting conservation action, as they show that traditional land‐use practices, protected areas and reduction of nitrogen input are important to preserve Orthoptera. The results also show that climate change is driving both range expansion and retraction of species. Therefore, insect monitoring is critical to understanding insect population trends and implementing the necessary actions.

The Effects of Environmental Changes on Plant Species and Forest Dependent Communities in the Amazon Region

We review the consequences of environmental changes caused by human activities on forest products and forest-dependent communities in the Amazon region—the vast Amazonas River basin and the Guiana Shield in South America. We used the 2018 and 2021 Intergovernmental Panel on Climate Change reports and recent scientific studies to present evidence and hypotheses for changes in the ecosystem productivity and geographical distribution of plants species. We have identified species associated with highly employed forest products exhibiting reducing populations, mainly linked with deforestation and selective logging. Changes in species composition along with a decline of valuable species have been observed in the eastern, central, and southern regions of the Brazilian Amazon, suggesting accelerated biodiversity loss. Over 1 billion native trees and palms are being lost every two years, causing economic losses estimated between US$1–17 billion. A decrease in native plant species can be abrupt and both temporary or persistent for over 20 years, leading to reduced economic opportunities for forest-dependent communities. Science and technology investments are considered promising in implementing agroforestry systems recovering deforested and degraded lands, which could engage companies that use forest products due to supply chain advantages.

Individual consistency in migration strategies of a tropical seabird, the Round Island petrel

BackgroundIn migratory species, the extent of within- and between-individual variation in migratory strategies can influence potential rates and directions of responses to environmental changes. Quantifying this variation requires tracking of many individuals on repeated migratory journeys. At temperate and higher latitudes, low levels of within-individual variation in migratory behaviours are common and may reflect repeated use of predictable resources in these seasonally-structured environments. However, variation in migratory behaviours in the tropics, where seasonal predictability of food resources can be weaker, remains largely unknown.MethodsRound Island petrels (Pterodroma sp.) are tropical, pelagic seabirds that breed all year round and perform long-distance migrations. Using multi-year geolocator tracking data from 62 individuals between 2009 and 2018, we quantify levels of within- and between-individual variation in non-breeding distributions and timings.ResultsWe found striking levels of between-individual variation in at-sea movements and timings, with non-breeding migrations to different areas occurring across much of the Indian Ocean and throughout the whole year. Despite this, repeat-tracking of individual petrels revealed remarkably high levels of spatial and temporal consistency in within-individual migratory behaviour, particularly for petrels that departed at similar times in different years and for those departing in the austral summer. However, while the same areas were used by individuals in different years, they were not necessarily used at the same times during the non-breeding period.ConclusionsEven in tropical systems with huge ranges of migratory routes and timings, our results suggest benefits of consistency in individual migratory behaviours. Identifying the factors that drive and maintain between-individual variation in migratory behaviour, and the consequences for breeding success and survival, will be key to understanding the consequences of environmental change across migratory ranges.

Driving mechanisms of climate-plant-soil patterns on the structure and function of different grasslands along environmental gradients in Tibetan and Inner Mongolian Plateaus in China

Grassland plants contribute to carbon fixation through photosynthesis, which can in turn produce plant biomass. Previous studies have demonstrated that vegetation productivity is enhanced by improved soil nutrient status in humid environments and is influenced by climate in arid environments. However, the responses of biomass productivity to different patterns of climate-plant-soil in different natural grassland ecosystems have not been clearly and comprehensively analyzed. In this study, we systematically explore the functional patterns of different grasslands, as well as the underlying mechanisms in the response to key climatic, soil, and plant factors. The survey range covered broad environmental gradients from humid, semi-arid, to arid environments in Tibetan and Inner Mongolian Plateaus. We found that the above- and belowground biomass production gradually decreased from humid, semi-arid, to arid environments. Biomass production was sensitive to climatic factors in different environments. However, compared to soil and plant factors, climate was always the most important factor determining biomass production in all grassland types. Furthermore, biomass production was regulated mainly by climate and soil characteristics in humid environments, but by climate in arid environments. Specifically, the corresponding limiting factors of each factor largely dominated the effects of the corresponding factors on different grasslands. For instance, the climate dominated by temperature negatively influenced the soil nutrient availability and then influenced the aboveground biomass production in alpine humid grasslands. These findings enhance our understanding of the heterogeneity of mechanisms of different grasslands along broad environmental gradients, which are crucial for predicting the effects and consequences of environmental change on terrestrial ecosystem functioning.

Spatiotemporal beta diversity of plankton species and their interactions in permanent and temporal waterholes in a semiarid savannah

ABSTRACT Freshwater communities can vary greatly across space and time. Studying these variations (i.e., spatial and temporal beta diversity) provides fundamental information on the processes that maintain diversity and on the consequences of environmental changes on communities. Recently, drying events have been shown to strongly affect the spatial and temporal beta diversity of temperate freshwater ecosystems, but the effects of such events are mostly unknown for freshwater communities in semiarid climates frequently submitted to drying up. In addition, studies have so far focused on variations in species composition (i.e., species beta diversity), but variations in species trophic interactions (i.e., food web beta diversity) can give additional insights on how community functioning varies in space and time. We combined species and food web perspectives to explore the spatiotemporal beta diversity of plankton species and their trophic interactions in waterholes undergoing different water level regimes: either an alternation between dry and water-full states, or a permanent water-full state due to water pumping. Our results show that waterholes with artificial water pumping do not differ from natural waterholes in their contribution to spatiotemporal beta diversity. Instead, beta diversity is strongly driven by temporal variations of species composition and food web structure during the dry season, which is characterized by degraded planktonic communities with a low richness, diversity, and connectance. Species- and interaction-based approaches give complementary information on the spatiotemporal beta diversity by highlighting different planktonic communities with contrasted functioning.