Decrease In Species Richness Research Articles

Anthropogenic activities decrease functional richness over time, but not other functional aspects of the fish community in a tropical bay

Functional diversity can be used to help understanding the processes shaping biological communities and the effects of human disturbances on the ecosystem's services. Untangling these biological processes is crucial to apply effective policies aiming the biodiversity conservation. Temporal changes (1983–1985, 1999–2001 and 2017–2019) in five functional indices (functional richness, divergence, evenness, specialization and originality) of the fish communities in two zones (inner and outer) of shallow areas in a tropical bay heavily human-impacted in recent decades were evaluated. The tested hypothesis was that functional indices decrease over time, because of the environmental degradation. A substantial decrease in species richness and abundance in the more recent periods (1999–2002 and 2017–2019) compared to 1983–1985 was observed. However, the functional structure remained relatively stable, with the exception of functional richness that showed a significant decrease over time. The apparent stability in the other functional indices may be due to the presence of dominant and functionally redundant species over time that compensates for the loss of species while maintaining similar functions. It was also discovered that decreases in fish richness in shallow bay areas result in losses in functional richness, with resident fish and benthivorous species being the most affected by environmental degradation. By employing a comprehensive approach that integrates the use of functional indices and taxonomic diversity to assess temporal changes in the fish community, it provides a broader understanding of ecological processes. Such insights could prove invaluable in guiding the implementation of conservation strategies.

Intraspecific Trait Variation Regulates Biodiversity and Community Productivity of Shrublands in Drylands

Intraspecific variation (Intra-V) has played an important role in determining the responses of ecosystem functions to climate change. However, its specific role in the regulation of ecosystem functions during community assembly is less investigated. In this study, we conducted a transect survey in northwest China and determined different plant functional types, namely resource-conservative, medium, and resource-acquisitive strategies, which describe resource-use strategies of plants in multi-functional dimensions. Plant functional traits including canopy, wood density (WD), height, specific leaf area (SLA), and leaf nitrogen (N) and phosphorus (P) concentrations were determined. Ecological filters, including external filtering (assembly processes at the regional scale), internal filtering (assembly processes within a certain community), and functional redundancy, were employed to examine plant environment interactions. We found that with the decrease in environmental pressure, dominant shrub plants changed from conservative to acquisition species in drylands. Specifically, a benign environment (such as stable and adequate precipitation, loose soil, and increased acid deposition) significantly increased plant mean traits, such as SLA and WD of shrubs, especially for conservative strategy plants. In addition, a benign environment mainly reduced the functional redundancy of SLA (FRedSLA) by strengthening internal filtering and, ultimately, increased aboveground biomass but decreased species richness. Our results suggest that conservative strategy plants with stronger adaptability to the external environment may exhibit more competitive advantages and play a more important role in community construction under future climate scenarios of gradual warming and wetting in northwest China. Our results also revealed that trait-based Intra-V may be a more reasonable ecological filter than plant mean traits for predicting the structure and function of dryland ecosystems.

Ecological and socioeconomic impacts of Lantana camara invasion: A case study in central India

The study investigates the impact of Lantana camara, an invasive alien species, on biodiversity, agricultural productivity, and non-timber forest products (NTFP) in central India. The aggressive growth and spread of the weed have resulted in the displacement of native flora and fauna, leading to substantial ecological and economic consequences. Regression analysis reveals a statistically significant negative correlation between proximity to Lantana camara infested plots and average annual crop loss, with closer proximity resulting in higher crop destruction. Additionally, a Wilcoxon signed-rank test confirms substantial reductions in NTFP collection post-infestation, highlighting significant economic losses for local communities reliant on these resources. The study also employs linear and non-linear regression analyses to assess the impact of Lantana camara infestation on species richness across various vegetation species, revealing a consistent negative effect on biodiversity. ANOVA and SIMPER analyses further corroborate these findings, indicating significant decreases in species richness, particularly among NTFP species. The results underscore the urgent need for effective management strategies to mitigate the adverse ecological and socioeconomic effects of Lantana camara invasions, emphasizing conservation efforts and sustainable practices to support the livelihoods of affected communities.

Vrba was right: Historical climate fragmentation, and not current climate, explains mammal biogeography.

Climate plays a crucial role in shaping species distribution and evolution over time. Dr Vrba's Resource-Use hypothesis posited that zones at the extremes of temperature and precipitation conditions should host a greater number of climate specialist species than other zones because of higher historical fragmentation. Here, we tested this hypothesis by examining climate-induced fragmentation over the past 5 million years. Our findings revealed that, as stated by Vrba, the number of climate specialist species increases with historical regional climate fragmentation, whereas climate generalist species richness decreases. This relationship is approximately 40% stronger than the correlation between current climate and species richness for climate specialist species and 77% stronger for generalist species. These evidences suggest that the effect of climate historical fragmentation is more significant than that of current climate conditions in explaining mammal biogeography. These results provide empirical support for the role of historical climate fragmentation and physiography in shaping the distribution and evolution of life on Earth.

The overlooked margins: how cities impact diversity of plants and terrestrial invertebrates along urban streams

The effect of different urbanization levels on terrestrial biodiversity associated with riparian zones remains poorly studied, despite the important ecosystem services it provides in cities. Studies focused on aquatic ecosystems in urban streams reported decreases in ecological quality and species richness, and lack of sensitive taxa. Thus, we investigated the impact of urbanization on riparian zone flora and terrestrial invertebrates using as case studies nine urban streams spanning an urbanization gradient in the Portuguese city of Coimbra. An unexpectedly high number of taxa were identified (163 plants, 80 terrestrial invertebrates), 80% new registrations for the region and one endemic-rare plant. Yet, diversity varied across streams, β-diversity reaching 39% Bray-Curtis similarity and averaging 25%, due to many underrepresented terrestrial taxa (N = 62 observed only in one site). Variation across the urbanization gradient reached 59% in plants and 82% in terrestrial invertebrates. High numbers of non-native taxa (13%; N = 32), mostly plants, suggested urbanization factors, e.g. human interference and discharge variation, may have favored invasions. Indeed, constructed natural spaces along streams, like parks, supported less biodiversity. Moreover, plant richness, especially of riparian plants, was correlated negatively with percentages of surrounding impervious areas and positively with water quality. This shows urbanization has negative effects on riparian vegetation, and water quality impacts both aquatic and terrestrial communities. Our results stress urban streams as novel ecosystems constituted by high numbers of non-native taxa, and the significance of riparian zones for biodiversity preservation. Less intense intervention on riparian vegetation is recommended to increase biodiversity.

Disturbance and diversity: Lichen species richness decreases with increasing anthropogenic disturbance

Anthropogenic disturbance is rapidly increasing through habitat degradation, development, and deforestation. Gaps remain in understanding the effects of this disturbance on diverse and ecologically important organisms such as lichens. In North America, studies have focused on epiphytic macrolichens and catastrophic disturbance, largely ignoring microlichens and less severe disturbances. The Intermediate Disturbance Hypothesis predicts these moderate disturbances will lead to higher species richness. Here we examine the effects of anthropogenic disturbance in the form of land management on overall lichen richness, including microlichens, and on the species richness of eight lichen functional groups. The study draws on a comprehensive data set of 872 species, in 208 one-hectare plots throughout the Southern Appalachian Mountains, a global biodiversity hotspot in eastern North America. A habitat quality index based on an established forestry metric was used as a proxy for anthropogenic disturbance and was quantified using a 10-part score including categories such as percent native tree canopy cover and degree of fragmentation. Linear models were used to compare habitat quality scores to overall species richness and to species richness of functional groups. Rather than following the Intermediate Disturbance Hypothesis, all groups uniformly follow a negative linear relationship: as disturbance increases, species richness decreases. This pattern held even for widely variable functional groups such as morphotype. Effective conservation of lichen richness should prioritize the maintenance of existing older, less-disturbed stands within large, contiguously forested areas.

A multitaxa approach to biodiversity inventory in Matela protected area (Terceira, Azores, Portugal).

This manuscript is the first contribution of the project, "Matela - uma ilha de biodiversidade" ("Matela - an island of biodiversity"), that aims to restore the native vegetation within the Azorean Protected Area of the Terceira Island Nature Park known as the "Protected Area for the Management of Habitats or Species of Matela" (TER08), situated on Terceira Island, the Azores Archipelago, Portugal. This small fragment of native forest, positioned at a low-medium altitude (300-400 m a.s.l.), is facing some conservation impacts as a consequence of the spread of different invasive exotic plant species, mainly Pittosporumundulatum, Rubusulmifolius and Hedychiumgardnerianum. The database we present encompasses diverse taxonomic groups, including bryophytes, vascular plants, arthropods, birds and mammals. It is derived from intensive sampling campaigns conducted in 2022, but some data from a previous vascular plant survey in 2015 were also included. The objective of this study was to provide an updated inventory of bryophytes, vascular plants, arthropods, birds and mammals within this protected area. In this way we are providing the reference conditions necessary for the monitoring of the impacts of the current ongoing restoration efforts within the project "Matela - an island of biodiversity". Whenever feasible, the present inventory is juxtaposed with historical data from previous surveys conducted in Matela. In the realm of bryophytes, our analysis revealed the presence of 75 taxa, comprising 44 mosses and 32 liverworts. Amongst these, 71 were indigenous, while three remained indeterminate and one, Campylopusintroflexus, was identified as invasive. A comparison with previous historical data revealed a decrease in species richness, which was partially counterbalanced by the discovery of 23 new recorded species in the area.Regarding vascular plants, we distinguished 54 species, comprising 28 indigenous and 26 introduced taxa. Almost 80% of the inventoried species (n = 43) were newly documented in Matela.The study of arthropods encompassed a total of 103 taxa. Within the realm of soil arthropods, we documented eight indigenous and 25 introduced taxa, witnessing the disappearance of endemic species alongside a substantial increase in introduced ones between 2002 and 2022. Canopy arthropods, totalling 36 indigenous and 18 introduced taxa, exhibited few changes when compared with data from 2002. SLAM traps captured 24 indigenous and 15 introduced arthropod taxa and no historical data are available for comparison.As for avian species, we noted 12 indigenous birds and one introduced species, confirming the presence of most of the historical recorded native species.The mammalian census revealed eight introduced species, setting new precedents for Matela, alongside the identification of one endemic species: the Azorean endemic bat Nyctalusazoreum.

Black soldier fly bioconversion to cultivated meat media components using blue catfish gut microbiome

This study aimed to develop low-cost media for cell-cultivated seafood using gut-microbial community-assisted fermentation. Black soldier fly larvae (Hermetia illucens) were used as the substrate and exposed to gut microbial communities isolated from blue catfish (Ictalurus furcatus). Fermentation led to a decrease in species richness, with the loss of important chitinase and protease-producing genera such as Pseudomonas and Clostridiaceae. However, there was an increase in Paraclostridium and members of the Enterobacteriaceae. In addition, the effect of fermented hydrolysates from BSFL on the proliferation of zebrafish embryo fibroblasts was tested in comparison to fetal bovine serum (FBS) in in vitro cell cultivation. Lower concentrations of FBS resulted in decreased cell density and altered cell morphology. The supplementation of hydrolysate B at high peptide concentrations had cytotoxic effects on the cells, while at lower peptide concentrations, it improved cell proliferation only in cultures with 2.5 % FBS.

Habitat modifies the relationship between grass and herbivore species richness in a South African savanna.

The savanna ecosystem is dominated by grasses, which are a key food source for many species of grazing animals. This relationship creates a diverse mosaic of habitats and contributes to the high grass species richness of savannas. However, how grazing interacts with environmental conditions in determining grass species richness and abundance in savannas is still insufficiently understood. In the Kruger National Park, South Africa, we recorded grass species and estimated their covers in 60 plots 50 × 50 m in size, accounting for varying proximity to water and different bedrocks. To achieve this, we located plots (i) near perennial rivers, near seasonal rivers, and on crests that are distant from all water sources and (ii) on nutrient-rich basaltic and nutrient-poor granitic bedrock. The presence and abundance of large herbivores were recorded by 60 camera traps located in the same plots. Grass cover was higher at crests and seasonal rivers than at perennial rivers and on basalts than on granites. The relationship between grass species richness and herbivore abundance or species richness was positive at crests, while that between grass species richness and herbivore species richness was negative at seasonal rivers. We found no support for controlling the dominance of grasses by herbivores in crests, but herbivore-induced microsite heterogeneity may account for high grass species richness there. In contrast, the decrease in grass species richness with herbivore species richness at seasonal rivers indicates that the strong grazing pressure over-rides the resistance of some species to grazing and trampling. We suggest that the relationships between grasses and herbivores may work in both directions, but the relationship is habitat-dependent, so that in less productive environments, the effect of herbivores on vegetation prevails, while in more productive environments along rivers the effect of vegetation and water supply on herbivores is more important.

The role of abiotic and biotic factors within influencing macroinvertebrate communities in a subtropical eutrophic reservoir with thermal stratification

ABSTRACT In this study, we investigated the plankton, water, and macroinvertebrates in Nanwan Reservoir, a subtropical eutrophic reservoir with thermal stratification. We evaluated the status of macroinvertebrate communities and explored the relationships between macroinvertebrate community status and both abiotic and biotic factors. This reservoir exhibited the worst water quality and a high risk of algal blooms in the autumn, whereas it had the best water quality in the spring. The presence of thermal stratification adversely affected macroinvertebrate communities, leading to decreases in species richness, abundance, and diversity. The water characteristics and dominant macroinvertebrate species confirmed that the reservoir was experiencing progressive eutrophication. During the thermal stratification period, the reservoir exhibited a worse status of macroinvertebrate communities, accompanied by an abundance of plankton. The results of PLSR and the Spearman rank test revealed that several abiotic factors, such as water temperature, chlorophyll-a, soluble phosphate, pH, and transparency, as well as biotic factors including the abundance of protozoans, Cyanobacteria, phytoplankton, Bacillariophyta, and Euglenophyta, were the most important factors affecting macroinvertebrate communities. The results of PLS-SEM revealed that both abiotic factors and biotic factors had non-negligible effects on the status of macroinvertebrate communities, with higher effect from abiotic factors compared to biotic factors.

Multi-omics analyses reveal interactions between the skin microbiota and skin metabolites in atopic dermatitis.

Atopic dermatitis (AD) is one of the most common inflammatory skin diseases. Skin microecological imbalance is an important factor in the pathogenesis of AD, but the underlying mechanism of its interaction with humans remains unclear. 16S rRNA gene sequencing was conducted to reveal the skin microbiota dynamics. Changes in skin metabolites were tracked by LC-MS metabolomics. We then explored the potential mechanism of interaction by analyzing the correlation between skin bacterial communities and metabolites in corresponding skin-associated samples. Samples from 18 AD patients and 18 healthy volunteers (HVs) were subjected to 16S rRNA gene sequencing and LC-MS metabolomics. AD patients had dysbiosis of the skin bacterial community with decreased species richness and evenness. The relative abundance of the genus Staphylococcus increased significantly in AD, while the abundances of the genera Propionibacterium and Brevundimonas decreased significantly. The relative abundance of the genera Staphylococcus in healthy females was significantly higher than those in healthy males, while it showed no difference in AD patients with or without lesions. The effects of AD status, sex and the presence or absence of rashes on the number of differentially abundant metabolites per capita were successively reduced. Multiple metabolites involved in purine metabolism and phenylalanine metabolism pathways (such as xanthosine/xanthine and L-phenylalanine/trans-cinnamate) were increased in AD patients. These trends were much more obvious between female AD patients and female HVs. Spearman correlation analysis revealed that the genus Staphylococcus was positively correlated with various compounds involved in phenylalanine metabolism and purine metabolic pathways. The genera Brevundimonas and Lactobacillus were negatively correlated with various compounds involved in purine metabolism, phenylalanine metabolism and sphingolipid signaling pathways. We suggest that purine metabolism and phenylalanine metabolism pathway disorders may play a certain role in the pathogenic mechanism of Staphylococcus aureus in AD. We also found that females are more likely to be colonized by the genus Staphylococcus than males. Differentially abundant metabolites involved in purine metabolism and phenylalanine metabolism pathways were more obvious in female. However, we should notice that the metabolites we detected do not necessarily derived from microbes, they may also origin from the host.

Large-Scale Monitoring of Bird Communities along an Altitudinal Gradient in Two Central High Atlas Valleys

Altitude is one of the determinant factors that influence the spatial distribution of birds and their species richness. However, few investigations studied its influence on African bird communities over a wide gradient in North Africa. Considering this knowledge gap, 194 sampling points were carried out along altitudinal gradient (773 to 2595 m) in two adjacent mountainous valleys in the Central High Atlas of Beni Mellal in Morocco, Aït Bouguemmaz (AB), and Ahançal (OA). Each valley was divided into three altitudinal intervals (low, medium, and high zones). For each spatial subdivision, we studied the phenological cycle, in the sense that each valley underwent a four-season monitoring, during 2018 and 2019. The results showed 131 species in the study area in 43 families; both valleys had similar community richness, but they differed by the phenological status of their species. Indeed, the increase in altitude led to a decrease in bird species richness, while it does not show any correlation with abundance. In addition, richness and abundance increased during the high-productivity seasons (i.e., spring and summer). Although these results were expected, they provide an opportunity to compare these results with higher latitude communities in Europe and to better focus future large-scale investigations on the combined influence of latitude and altitude on birds.

Rarities pattern of vascular plants in the high-altitude forests of Indian western Himalaya: Conservation implications

The assessment of plant rarity patterns and mapping of endemic species is a challenging task, however, this kind of assessment having great conservation significance. In the present study, a classification system of rarity, considering biogeographical, ecological and abundance of species was developed along with assessing the vegetation composition. Following systematic random approach of vegetation sampling, three altitude transects were sampled within each 100 m interval in three possible aspects (North-West, North-East and South-West) in the high-altitude forested zone (2000–3300 m asl) of Kedarnath Wildlife Sanctuary (KWS). The study identified a total of 295 plant species (191 genera and 70 families) in the studied region. Considering different attributes of rarity, 8- rarity groups were used for identification of rare and endemic plants. Altogether, most of the species exhibited wide geographical distribution an attribute of commonness, and few of these have narrow distributions due to habitat specificity. The lower altitudinal zone exhibited the maximum floristic diversity (184 spp.; 62.4 %), and minimum in the higher zone (134 spp.; 45.4 %). Tree species richness decreases, and its endemic subset increased along the altitudinal gradient due to remoteness, habitat heterogeneity, isolation of the areas and other environmental factors. A sharp decline was observed in the tree species richness from lower (33 spp.; 84.6 %) to higher altitude (8 spp.; 20.51 %). The species to genera ratio in the entire altitudinal range was 1.2 for trees and 1.6 for shrubs and herbs. Rarity analysis of these native and endemic species has highlighted conservation priorities at local and regional scale.

Changes in taxonomic and functional composition of subalpine plant communities in response to climate change under contrasting conditions of bedrock and snow cover duration

AbstractQuestionsWe assessed interactions between climate change, bedrock types and snow cover duration on the trajectories of taxonomic and functional composition of subalpine plant communities. We predict (i) an increase in species richness on siliceous bedrock due to a reduced competition and a decrease in richness on calcareous bedrock due to increasing drought stress; (ii) decreasing snow cover duration should induce a higher shrub encroachment in hollows as compared to ridges; and (iii) increasing growing season temperature should induce taller sizes and more conservative growth traits, in particular in hollows.LocationSubalpine belt of the Grandes Rousses mountain range, southwestern Alps (France).Methods189 vegetation plots were sampled in 1997 and 2017–2018. The duration of snow cover was assessed during two years in 1995–1997 and five functional traits were measured on 108 species in 2021. We performed multivariate analyses, quantified community‐weighted means (CWM) of traits and used ANOVAs to detect responses to local‐scale factors and changes in snow cover, temperature and precipitation since 1997 according to a nearby meteorological station.ResultsOverall, taxonomic composition weakly changed and changes were more dependent on the position of communities along the snow cover duration gradient than on their bedrock type. The abundance of drought‐tolerant species increased at the border of hollows and there was, over all communities, a slight increase in the abundance of dwarf shrubs and tall herbaceous species, a strong decrease in short herbaceous species and, thus, an overall decrease in species richness. There were important overall changes in CWM of size traits, in particular leaf area which increased the most in hollows irrespective of bedrock types.ConclusionIn this subalpine site the effects of decreasing snow cover duration overwhelmed the effects of bedrocks, which may explain the overall increase in competitive species and decrease in species richness.

Substantial urbanization-driven declines of larval and adult moths in a subtropical environment.

Recent work has shown the decline of insect abundance, diversity and biomass, with potential implications for ecosystem services. These declines are especially pronounced in regions with high human activity, and urbanization is emerging as a significant contributing factor. However, the scale of these declines and the traits that determine variation in species-specific responses remain less well understood, especially in subtropical and tropical regions, where insect diversity is high and urban footprints are rapidly expanding. Here, we surveyed moths across an entire year in protected forested sites across an urbanization gradient to test how caterpillar and adult life stages of subtropical moths (Lepidoptera) are impacted by urbanization. Specifically, we assess how urban development affects the total biomass of caterpillars, abundance of adult moths and quantify how richness and phylogenetic diversity of macro-moths are impacted by urban development. Additionally, we explore how life-history traits condition species' responses to urban development. At the community level, we find that urban development decreases caterpillar biomass and adult moth abundance. We also find sharp declines of adult macro-moths in response to urban development across the phylogeny, leading to a decrease in species richness and phylogenetic diversity in more urban sites. Finally, our study found that smaller macro-moths are less impacted by urban development than larger macro-moths in subtropical environments, perhaps highlighting the tradeoffs of metabolic costs of urban heat favoring smaller moths over the relative benefits of dispersal for larger moths. In summary, our research underscores the far-reaching consequences of urbanization on moths and provides compelling evidence that urban forests alone may not be sufficient to safeguard biodiversity in cities.

Butterfly loss in urban landscapes and nature reserves

ContextUrbanization and landscape homogenization are main drivers causing biodiversity loss across the globe. The transformation of natural and semi-natural habitats into agro-environments and settlement areas causes the reduction of species diversity, and thus faunal homogenization. ObjectiveIn this study, we analyse changes in land-cover and habitat configuration and test for changes in species richness and community composition of butterflies in an urban area and a nature reserve. MethodWe analysed historical and recent aerial and satellite pictures, and studied the butterfly fauna for two areas in northern Austria, the urban area around Salzburg city and the nature reserve Bluntautal in close geographic proximity. For these analyses we consider the period 1946–2018. ResultsThe proportion of settlement area and forest increased in average by about 5%. Size of field copses increased and small-scale connectivity and thus landscape complexity decreased in both areas. In the same time span, we found a decrease in butterfly species richness for both areas, and in the nature reserve Bluntautal particularly for the past two decades by 50%. The species community composition changed significantly, with severe losses of specialist and xerothermophilic species which rely on open and extensively used ecosystems. ConclusionsThe findings underpin that the reduction of landscape complexity and the intensification of land-use including urbanization drives the loss of diversity of butterflies and changes in species composition, today dominated by some few generalist species. This trend is particularly observable for the nature reserve Bluntautal, where a large proportion of species diversity has disappeared in recent years despite nature conservation. This case underlines habitat management in nature reserves is needed to hold a high level of habitat quality and to preserve the entire species diversity.

Alterations in the Gut Microbiota in Chinese Patients With Intrahepatic Cholestasis of Pregnancy

Intrahepatic cholestasis of pregnancy (ICP) is a pregnancy‐specific liver disease and the second most frequent cause of jaundice in pregnancy, but the etiology of it is poorly understood. By collecting blood and fecal samples from 12 healthy pregnant women (CON group) and 32 ICP patients (ICP group) in China, we performed 16s rRNA gene sequencing and analyzed microbial diversity. The results showed a decrease in species richness of the ICP group compared to that in the CON group, with a significant difference in species diversity between the two groups. Differential analysis revealed the following biomarkers: s__unclassified__Megamonas, g__Megamonas, f__Selenomonadaceae, c__Bacilli, and o__Lactobacillales. Importantly, we found a decrease in species richness of Selenomonadaceae at the family level and decreased bacilli at the class level in ICP patients. Correlation network analysis and functional gene prediction were performed accordingly. Our data provided new information linking microbiota and ICP, and are possibly helpful for further exploration of the disease.

Relatório temático sobre espécies exóticas invasoras no Brasil: sumário para tomadores de decisão

Abstract Biological invasions are one of the major threats to biodiversity and good quality of life, resulting from the translocation of species by human action. There are more than 500 alien species currently invading ecosystems in Brazil, particularly plants and fishes, while little is known about invasive microorganisms. Although invasive alien species are present in all ecosystems in the country, most have been recorded in habitats with greater human interference, such as urban and peri-urban areas, farmland, dams, reservoirs, ports, and canals. Historically, the southern and southeastern regions of Brazil have had more invasive alien species, but there has been an increase in the number of invasive alien species in the central-western and northern regions in recent decades. The ornamental trade of plants and fishes as well as the illegal pet trade of wild mammals and reptiles are some of the main pathways for invasive species introduction and spread in Brazil. Breeding and cultivation systems that allow escape to natural areas are a relevant route of species introductions in freshwater ecosystems, while unintentional introductions from shipping and infrastructure are of extreme concern in marine ecosystems. The negative impacts of invasive alien species on the biota mainly include changes in community structure and local decrease in native species richness, mediated by predation, competition, and ecosystem changes. Most negative impacts are recorded for intentionally introduced species, such as fishes and plants, but unintentional introductions have led to impacts on good quality of life, with associated costs and impacts on human health. The management of biological invasions faces challenges that need to be overcome, such as the lack of public knowledge about the impact of invasive alien species, the popular appeal of charismatic invasive species or those used by humans, and the use of controversial control techniques. However, successful experiences of eradication and control in terrestrial and marine ecosystems have been recorded, some of them involving public engagement in management actions. Recognizing the issue as a cross-cutting public policy and developing ongoing governance experiences are fundamental goals for the management of invasive alien species in Brazil.

Global response of different types of grasslands to precipitation and grazing, especially belowground biomass

Precipitation and grazing both modify the structure and function of grassland. Although the effects of site-scale precipitation and grazing on vegetation communities have been investigated, the differences between different grassland types at the global scale are still not clear. Therefore, we conducted a global-scale meta-analysis synthesizing 107 field studies with different grassland types (savanna grassland, temperate grassland, cold grassland, and alpine grassland) to quantify the effects of global changes in precipitation and grazing on community structure and function of grassland types. Results showed that regardless of grassland type, increased precipitation increased species richness by 7.8%, decreased belowground biomass (BGB) by 20.0%, and increased aboveground biomass (AGB) by 22.9%, but interestingly, decreased precipitation increased BGB by 17.7%, decreased AGB by 22.8%, and decreased species richness by 13.7%. Species richness of global grassland vegetation was positively correlated with grazing intensity. The total vegetation community biomass (TB) increased by 11.7% under moderate grazing intensity, while the species diversity of global grassland vegetation increased by 10.7% under heavy grazing intensity. Increased precipitation had negatively impacted BGB in temperate grassland, while increased precipitation significantly increased cool grassland BGB. In savanna grasslands, vegetation AGB decreased with increasing precipitation. Our results highlight the impact of altered precipitation on grassland vegetation under different climate types. We suggest that future studies of grassland management should consider incorporating grazing intensity and climate type, which will help to protect grassland vegetation species diversity and predict future carbon dynamics.

Short-interval, high-severity wildfires cause declines in soil seed bank diversity in montane forests of south-eastern Australia

Wildfires in forested ecosystems are increasing in severity and extent. The adaptations many plants have acquired in response to their natural fire regime may not be sufficient to allow some species to persist. This could impact the forest understorey and its seed bank, which are vital reservoirs of biodiversity, and forest resilience in the face of global change. We present a case study of the montane forests of south-eastern Australia, an area subjected to an increase in frequency and severity of fires. We utilise field surveys and a soil seed bank germination study to investigate if short-interval, high-severity wildfires affect the understorey diversity in montane forests, and if the extant vegetation and the soil seed bank exhibit contrasting responses. We consider species diversity and plant functional traits to explore plant diversity in long unburned sites, and sites with one, two or three short-interval, high-severity fires in the past 25 years. With increasing fire frequency, we found a decrease in total species richness, Shannon’s diversity, and the richness of resprouters in the soil seed bank, contrasting a lack of response in the extant vegetation. Increased fire frequency shifted the species composition and the frequency of plant functional groups of both extant vegetation and soil seed bank towards a decrease in clonal resprouters and increase in grasses and other upright herbs. The frequency of wind-dispersed perennials and short-lived seeders and exotics increased sharply following single high severity burn, particularly in the soil seed bank, and remained elevated relative to long unburnt with subsequent fire. The combined species (extant vegetation plus soil seed bank) pool mirrored shifts in the frequency of functional groups in extant vegetation and soil seed bank. These findings highlight the importance of considering the soil seed bank when examining the effects of fire on fire-prone forests. Although a lack of response in the extant vegetation may be a buffering effect of the soil seed bank, the shift in the frequency of plant functional groups in the combined species pool suggests this cannot be maintained indefinitely. The increase in frequency and abundance of species characteristic of early successional states has implications for increased flammability and potential positive feedbacks between past fire and future fire, especially in a warming and drying climate. These shifts were independent of the fire response strategy of eucalypt canopy species raising significant questions of whether artificial re-seeding programs should extend beyond the current focus on obligate seeding forests and an obligate seeding tree.