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1.
An Acad Bras Cienc ; 93(suppl 3): e20201067, 2021.
Artículo en Inglés | MEDLINE | ID: mdl-34468489

RESUMEN

The lowlands of mid-latitude South America comprise complex temperate ecoregions characterized by a unique biodiversity. However, the processes responsible for shaping its species diversity are still largely unknown. Turnera sidoides subsp. carnea is a variable subspecies occurring in the lowlands of northeastern Argentina and Uruguay, extending to southern Paraguay and Brazil. It constitutes a good model to perform evolutionary studies. Here we used an integrative approach to understand the process of diversification within this subspecies and to increase the knowledge concerning patterns and processes responsible for shaping the species diversity in the temperate lowlands of South America. The results provided strong evidences that this subspecies is an autopolyploid complex per se, being in an active process of intrasubspecific diversification. Morphological and genetic data show that the diversity of T. sidoides subsp. carnea is in congruence with the great past and present abiotic and biotic variability of the mid-latitude South American lowlands. The evolutionary history of this subspecies is consistent with past fragmentation and allopatric differentiation at diploid level. Geographic isolation and local adaptation would have promoted strong morphological, ecological, and genetic differentiation, resulting in two morphotypes and different genetic groups indicative of incipient speciation.


Asunto(s)
Turnera , Argentina , Biodiversidad , Brasil , Diploidia , Filogenia , América del Sur
2.
Sci Total Environ ; 792: 148075, 2021 Oct 20.
Artículo en Inglés | MEDLINE | ID: mdl-34465033

RESUMEN

Polychaetes are one of the most diverse groups of marine organisms, characterized by high species richness, diversity of feeding guilds, life styles, and mobility types. Marine annelids are useful indicators of ecosystem responses to changes in environmental conditions. The aim of our study was to assess the influence of natural and anthropogenic factors on functional diversity of polychaete communities in the Gulf of Guinea, a large marine ecosystem (LME) located in West Africa. This area can be considered as a model marine ecosystem affected by various human influences, such as pollution associated with the oil industry. Material was collected in 2012 across the coast of Ghana. Samples were gathered along four transects, each with six sampling stations (25-1000 m depth range). Analyses of functional richness and evenness, based on generalized linear mixed-effect models and hierarchical partitioning, allowed for complex assessments of the interactions between polychaete communities and environmental factors (e.g., sediments, total organic matter, salinity, fluorescence, oxygen, concentration of toxic metals, total hydrocarbons). Overall species richness of polychaetes was outstandingly high, with 253 species recorded. Functional richness decreased along a depth gradient, while functional evenness increased with depth, and was positively correlated with Ba content, which reached the highest values in the upper bathyal. Gravel content was an important factor in shaping functional composition of shallow water communities. High values of functional richness observed in the shallows may be an expression of high stability of this ecosystem, at the same time indicating its high resilience. Elevated concentrations of lead also influenced community structure at a local scale. Our study demonstrated how a complex set of factors operating along a depth gradient can influence the functional composition of communities. These results are crucial for future management of industrial and environmental protection activities in this region.


Asunto(s)
Organismos Acuáticos , Ecosistema , Biodiversidad , Conservación de los Recursos Naturales , Ghana , Humanos
3.
Braz J Biol ; 83: e243666, 2021.
Artículo en Inglés | MEDLINE | ID: mdl-34495145

RESUMEN

Brazil is the world's richest country in biodiversity, including mammal species. In the Brazilian Cerrado biome, mammalian diversity is vast, with about 251 species, 32 of them are endemic and 22 listed as threatened species. In this work, we investigated species diversity of medium- and large-sized mammals in the private protected area RPPN Pontal do Jaburu (RPPN-PJ) and its surroundings, which is a flooded area located in an important biological corridor in the Cerrado-Amazon ecotone zone, a priority area for biodiversity conservation in Brazil. We used camera-trapping, active search (night and day), and track survey during dry season (Apr - Aug 2016). We recorded 29 mammal species, being the Carnivora order the most representative with 11 species. Regarding threat status, 35.7% of the recorded species were listed as threatened in Brazil and 32.1% worldwide. We highlight the high relative frequency of threatened species records such as Tapirus terrestris, Panthera onca, Blastocerus dichotomus, Pteronura brasiliensis, Priodontes maximus, and other, as well as the presence of the newly described aquatic mammal species Inia araguaiaensis. We stress the importance of RPPN-PJ and its surroundings for mammal conservation, which include complex habitats (wetlands) located in an important ecotone zone.


Asunto(s)
Mamíferos , Humedales , Animales , Biodiversidad , Brasil , Conservación de los Recursos Naturales , Especies en Peligro de Extinción
5.
Nature ; 597(7874): 7-8, 2021 09.
Artículo en Inglés | MEDLINE | ID: mdl-34465911
6.
Nat Commun ; 12(1): 5226, 2021 09 01.
Artículo en Inglés | MEDLINE | ID: mdl-34471105

RESUMEN

Marine phytoplankton and zooplankton form the basis of the ocean's food-web, yet the impacts of climate change on their biodiversity are poorly understood. Here, we use an ensemble of species distribution models for a total of 336 phytoplankton and 524 zooplankton species to determine their present and future habitat suitability patterns. For the end of this century, under a high emission scenario, we find an overall increase in plankton species richness driven by ocean warming, and a poleward shift of the species' distributions at a median speed of 35 km/decade. Phytoplankton species richness is projected to increase by more than 16% over most regions except for the Arctic Ocean. In contrast, zooplankton richness is projected to slightly decline in the tropics, but to increase strongly in temperate to subpolar latitudes. In these latitudes, nearly 40% of the phytoplankton and zooplankton assemblages are replaced by poleward shifting species. This implies that climate change threatens the contribution of plankton communities to plankton-mediated ecosystem services such as biological carbon sequestration.


Asunto(s)
Biodiversidad , Calentamiento Global , Biología Marina , Plancton/clasificación , Animales , Regiones Árticas , Cambio Climático , Ecosistema , Cadena Alimentaria , Fitoplancton , Temperatura , Zooplancton
9.
Environ Monit Assess ; 193(10): 647, 2021 Sep 14.
Artículo en Inglés | MEDLINE | ID: mdl-34519882

RESUMEN

Land managers need reliable metrics for assessing the quality of restorations and natural areas and prioritizing management and conservation efforts. However, it can be difficult to select metrics that are robust to sampling methods and natural environmental differences among sites, while still providing relevant information regarding ecosystem changes or stressors. We collected herbaceous-layer vegetation data in wetlands and grasslands in four regions of the USA (the Midwest, subtropical Florida, arid southwest, and coastal New England) to determine if commonly used vegetation metrics (species richness, mean coefficient of conservatism [mean C], Floristic Quality Index [FQI], abundance-weighted mean C, and percent non-native species cover) were robust to environmental and methodological variables (region, site, observer, season, and year), and to determine adequate sample sizes for each metric. We constructed linear mixed effects models to determine the influence of these environmental and methodological variables on vegetation metrics and used metric accumulation curves to determine the effect of sample size on metric values. Species richness and FQI varied among regions, and year and observer effects were also highly supported in our models. Mean C was the metric most robust to sampling variables and stabilized at less sampling effort compared to other metrics. Assessment of mean C requires sampling a small number of quadrats (e.g. 20), but assessment of species richness or FQI requires more intensive sampling, particularly in species-rich sites. Based on our analysis, we recommend caution be used when comparing metric values among sites sampled in different regions, different years, or by different observers.


Asunto(s)
Conservación de los Recursos Naturales , Ecosistema , Biodiversidad , Monitoreo del Ambiente , Estaciones del Año , Humedales
11.
J Hazard Mater ; 416: 125850, 2021 08 15.
Artículo en Inglés | MEDLINE | ID: mdl-34492801

RESUMEN

This study aims to unravel the microbial responses to Cr(VI) stress in anaerobic ammonium oxidation (anammox) reactor. The result showed that anammox process could tolerate 2 mg/L Cr(VI) after acclimation, while 5 mg/L Cr(VI) stress resulted in significant inhibition on anammox bacterial activity. Ca. Jettenia was the predominant anammox genus, whose abundance showed a decreasing tendency with increasing Cr(VI) dosage. Cr(VI) addition resulted in significant and irreversible changes in microbial community structure, and increased the relative influence of stochastic processes on community assembly. Furthermore, rare subcommunity contributed greatly to biodiversity of whole community (90.35%), while abundant subcommunity were more similar to the whole community. Importantly, Cr(VI) exposure caused greater variations in rare subcommunity compared with abundant one, indicating that rare taxa were more sensitive to Cr(VI) stress. This was further confirmed by ABT model, which showed higher relative influence of Cr(VI) on rare subcommunity. In addition, results suggested that rare taxa play essential roles in whole community stability, because of their great contribution to species richness and community variations, and keystone roles in ecosystem network. Moreover, network analysis showed that conditionally rare taxa frequently and positively interacted with abundant taxa, which may contribute to the community resilience to Cr(VI) stress.


Asunto(s)
Cromo , Microbiota , Bacterias/genética , Biodiversidad , Cromo/toxicidad , Oxidación-Reducción
12.
Ecol Lett ; 24(11): 2301-2313, 2021 Nov.
Artículo en Inglés | MEDLINE | ID: mdl-34472694

RESUMEN

The history of species immigration can dictate how species interact in local communities, thereby causing historical contingency in community assembly. Since immigration history is rarely known, these historical influences, or priority effects, pose a major challenge in predicting community assembly. Here, we provide a graph-based, non-parametric, theoretical framework for understanding the predictability of community assembly as affected by priority effects. To develop this framework, we first show that the diversity of possible priority effects increases super-exponentially with the number of species. We then point out that, despite this diversity, the consequences of priority effects for multispecies communities can be classified into four basic types, each of which reduces community predictability: alternative stable states, alternative transient paths, compositional cycles and the lack of escapes from compositional cycles to stable states. Using a neural network, we show that this classification of priority effects enables accurate explanation of community predictability, particularly when each species immigrates repeatedly. We also demonstrate the empirical utility of our theoretical framework by applying it to two experimentally derived assembly graphs of algal and ciliate communities. Based on these analyses, we discuss how the framework proposed here can help guide experimental investigation of the predictability of history-dependent community assembly.


Asunto(s)
Cilióforos , Biodiversidad , Redes Neurales de la Computación , Plantas
14.
Ambio ; 50(11): 1991-2008, 2021 Nov.
Artículo en Inglés | MEDLINE | ID: mdl-34519957

RESUMEN

We present climate-dependent changes in the high-mountain forest ecotone, old-growth forests, alpine phytocenoses, and deglaciated forelands in the Aktru glacial basin (Altai Republic, Russia). A number of independent sources (variations in upper treeline altitude, dendrochronological data, analysis of lacustrine sediments and botanical and geographical studies linked with the dynamics of glacial-dammed lakes in the Chuya and Kurai intermountain depressions) suggest Holocene temperatures reached about 4 °C higher than today. Unlike the European Alps, glaciers in the continental Altai Mountains disappeared before forming again. Also, the upper altitudinal limit of mountain forests during the Holocene was greater than in the European Alps. The high variability of mountain ecosystems in southern Siberia suggests their potential instability in a currently changing climate. However, periglacial successions associated with the strong continental climate and glacier retreat represent an area of increasing biodiversity and plant cover. The historical and current sensitivity of the continental mountains to climate variations which exceeds that of the European Alps requires greater understanding, environmental protection, and increased social responsibility for the consequences of anthropogenic contributions to climate change: the isolated Altai areas contribute little to climate changes, but are greatly affected by them.


Asunto(s)
Biodiversidad , Cambio Climático , Ecosistema , Cubierta de Hielo , Bosques , Federación de Rusia
15.
Oecologia ; 197(2): 511-522, 2021 Oct.
Artículo en Inglés | MEDLINE | ID: mdl-34535833

RESUMEN

Although functional and phylogenetic diversities are increasingly used in ecology for a variety of purposes, their relationship remains unclear, and this relationship likely differs among taxa, yet most recent studies focused on plants. We hypothesize that communities may be diverse in functional traits due to presence of: many phylogenetic lineages, trait divergence within lineages, many species and random functional variation among species, weak filtering of traits in favorable environments, or strong trait divergence in unfavorable environments. We tested these predictions for taxa showing higher (ants), or lower (spiders, ground beetles) degrees of competition and niche construction, both of which might decouple functional traits from phylogenetic position or from the environment. Studying > 11,000 individuals and 216 species from coastal heathlands, we estimated functional as minimum spanning trees using traits related to the morphology, feeding habits and dispersal, respectively. Relationships between functional and phylogenetic diversities were overall positive and strong. In ants, this relationship disappeared after accounting for taxonomic diversities and environments, whereas in beetles and spiders taxonomic diversity is related to functional diversity only via increasing phylogenetic diversity. Environmental constraints reduced functional diversity in ants, but affected functional diversity only indirectly via phylogenetic diversity (ground beetles) and taxonomic and then phylogenetic diversity (spiders and ground beetles). Results are consistent with phylogenetic conservatism in traits in spiders and ground beetles. In ants, in contrast, traits appear more phylogenetically neutral with any new species potentially representing a new trait state, tentatively suggesting that competition or niche construction might decouple phylogenetics from trait diversity.


Asunto(s)
Artrópodos , Escarabajos , Arañas , Animales , Biodiversidad , Escarabajos/genética , Ecosistema , Humanos , Filogenia
16.
Oecologia ; 197(2): 353-364, 2021 Oct.
Artículo en Inglés | MEDLINE | ID: mdl-34546495

RESUMEN

Beta-diversity was originally defined spatially, i.e., as variation in community composition among sites in a region. However, the concept of beta-diversity has since been expanded to temporal contexts. This is referred to as "temporal beta-diversity", and most approaches are simply an extension of spatial beta-diversity. The persistence and turnover of individuals over time is a unique feature of temporal beta-diversity. Nakadai (2020) introduced the "individual-based beta-diversity" concept, and provided novel indices to evaluate individual turnover and compositional shift by comparing individual turnover between two periods at a given site. However, the proposed individual-based indices are applicable only to pairwise dissimilarity, not to multiple-temporal (or more generally, multiple-unit) dissimilarity. Here, individual-based beta-diversity indices are extended to multiple-unit cases. In addition, a novel type of random permutation criterion related to these multiple-unit indices for detecting patterns of individual persistence is introduced in the present study. To demonstrate the usage the properties of these indices compared to average pairwise measures, I applied them to a dataset for a permanent 50-ha forest dynamics plot on Barro Colorado Island in Panama. Information regarding "individuals" is generally missing from community ecology and biodiversity studies of temporal dynamics. In this context, the methods proposed here are expected to be useful for addressing a wide range of research questions regarding temporal changes in biodiversity, especially studies using traditional individual-tracked forest monitoring data.


Asunto(s)
Biodiversidad , Bosques , Colorado , Ecología , Humanos , Panamá
17.
Mar Environ Res ; 171: 105459, 2021 Oct.
Artículo en Inglés | MEDLINE | ID: mdl-34478970

RESUMEN

Increased rainfall has become a key threat in recent decades for subtropical coastal regions. On sandy beaches that are associated with streams and rivers, the intensification of freshwater inputs is expected to reduce the salinity of interstitial waters and affect benthic biodiversity. Large freshwater gradients are promoted by river mouths and also change beach morphodynamic and sediment organic contents, which are covariates that have hindered the understanding of salinity-specific effects on benthic species in previous studies. Here, we aimed to assess how salinity reduction affects macrobenthic communities at small spatial scales to control the effects of environmental covariates. We assessed the macrofaunal spatial changes across few-meters gradients of freshwater influence (30 m) that were promoted by small streams (~2 m wide) within three subtropical beaches in southeastern Brazil. Our results showed that salinity was the only environmental factor that explained the macrofaunal variations across such small-scale gradients. We noted that salinity reductions decrease the overall macrobenthic abundance and richness in the first 15 m close to streams. Such variations are associated with changes in polychaete abundance (mainly Scolelepis squamata), which form larger patches with 1200-2800 individuals/m2 only at sites with high salinity (greater than 25). We also found that a salinity reduction from 33 to 20 may promote a decrease of 85% in polychaete abundance near the streams. Nevertheless, salinity reductions did not affect crustacea abundance across the gradient. In the current global change context, these results suggest that freshwater input has great potential to impact polychaete patches, reduce macrobenthic biomass and secondary production and thus threaten important beach functions and services, such as bioturbation and food provision for the top predators.


Asunto(s)
Poliquetos , Salinidad , Animales , Biodiversidad , Agua Dulce , Humanos , Ríos
18.
Mar Environ Res ; 171: 105458, 2021 Oct.
Artículo en Inglés | MEDLINE | ID: mdl-34478971

RESUMEN

Coastal habitat mosaics are among the most productive ecosystems around the globe, with many ecological and social-economic services provided. Their natural challenging conditions have always been a subject of concern for ecologist and conservationist, with a particular interest in understanding how its spatial and temporal dynamics influence ecosystem functioning. In this context, we aimed to assess tropical coastal dynamics using an integrative approach, measuring the different facets of fish diversity across space (habitats) and time (seasons). Three different estuarine systems and their adjacent areas in the southwestern Atlantic were monthly sampled between July 2017 and June 2018, in a sampling design that encompassed three different coastal mosaics with three habitat types (mangroves, seagrass and sandy beaches), and both seasons of the studied region (dry and rainy). Taxonomic, phylogenetic, and functional diversity were then evaluated with equivalent diversity measures to allow comparisons between them. Different patterns of species occurrence and distribution were found between habitats and seasons, which resulted in different effects on the abundance-weighted diversity dimensions. Although taxonomic diversity of habitats was greater during the rainy season (p = 0.03), a seasonal increase in phylogenetic diversity was only observed in the sandy beach habitat (p = 0.04). In contrast for the functional diversity, no significant differences were found among habitats in both seasons (p = 0.15), indicating high levels of redundancy. Our results showed that patterns in the occurrence and abundance of tropical fish species among habitats that comprise a coastal mosaic have different effects on distinct diversity dimensions. More precisely, for tropical coastal systems with marked seasonality, both habitats and season appear to play a synergic role in the maintenance of ecosystem functioning by enhancing functional and phylogenetic redundancy.


Asunto(s)
Ecosistema , Peces , Animales , Biodiversidad , Filogenia , Lluvia , Estaciones del Año
20.
Mar Environ Res ; 171: 105477, 2021 Oct.
Artículo en Inglés | MEDLINE | ID: mdl-34520892

RESUMEN

We investigated stratigraphic changes in mollusk death assemblages and geochemistry in sediment cores from four seagrass beds and one unvegetated site in the Gulf of Guanahacabibes (GG), NW Cuba. There was a transition from mangrove to seagrass beds, associated with sea level rise ∼6000 years ago. Sediment accumulation rates during the last century showed a general rise, but increased sharply after ∼1980, likely because of human activities. The GG displayed overall high mollusk γ-diversity, and our estimate of 189 species is biased toward the low end. High ß-diversity was driven by inter-site differences in grain size, vegetation cover, and nutrient input. Spatial heterogeneity within the basin influenced downcore abundance and diversity metrics, highlighting the influence of local drivers. Herbivorous gastropods dominated in seagrass beds and suspension feeder bivalves were dominant on sandy bottom. In the top parts of cores, species richness declined at two sites that were subject to high, human-mediated bulk sedimentation rates and eutrophication. Conservation measures are needed to preserve this hotspot of marine diversity.


Asunto(s)
Biodiversidad , Plomo , Animales , Cuba , Sedimentos Geológicos , Humanos , Moluscos
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