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1.
Glob Chang Biol ; 30(8): e17483, 2024 Aug.
Artículo en Inglés | MEDLINE | ID: mdl-39171768

RESUMEN

The role of plant biodiversity in stabilizing ecosystem multifunctionality has been extensively studied; however, the impact of soil biota biodiversity on ecosystem multifunctional stability, particularly under multiple environmental changes, remains unexplored. By conducting an experiment with environmental changes (adding water and nitrogen to a long-term grazing experiment) and an experiment without environmental changes (an undisturbed site) in semi-arid grasslands, our research revealed that environmental changes-induced changes in temporal stability of both above- and belowground multifunctionality were mainly impacted by plant and soil biota asynchrony, rather than by species diversity. Furthermore, changes in temporal stability of above- and belowground multifunctionality, under both experiments with and without environmental changes, were mainly associated with plant and soil biota asynchrony, respectively, suggesting that the temporal asynchrony of plant and soil biota has independent and non-substitutable effects on multifunctional stability. Our findings emphasize the importance of considering both above- and belowground biodiversity or functions when evaluating the stabilizing effects of biodiversity on ecosystem functions.


Asunto(s)
Biodiversidad , Pradera , Plantas , Suelo/química , Ecosistema , Microbiología del Suelo , Biota , Nitrógeno/análisis
2.
J Exp Biol ; 227(13)2024 Jul 01.
Artículo en Inglés | MEDLINE | ID: mdl-38856174

RESUMEN

Organisms regularly adjust their physiology and energy balance in response to predictable seasonal environmental changes. Stressors and contaminants have the potential to disrupt these critical seasonal transitions. No studies have investigated how simultaneous exposure to the ubiquitous toxin methylmercury (MeHg) and food stress affects birds' physiological performance across seasons. We quantified several aspects of energetic performance in song sparrows, Melospiza melodia, exposed or not to unpredictable food stress and MeHg in a 2×2 experimental design, over 3 months during the breeding season, followed by 3 months post-exposure. Birds exposed to food stress had reduced basal metabolic rate and non-significant higher factorial metabolic scope during the exposure period, and had a greater increase in lean mass throughout most of the experimental period. Birds exposed to MeHg had increased molt duration, and increased mass:length ratio of some of their primary feathers. Birds exposed to the combined food stress and MeHg treatment often had responses similar to the stress-only or MeHg-only exposure groups, suggesting these treatments affected physiological performance through different mechanisms and resulted in compensatory or independent effects. Because the MeHg and stress variables were selected in candidate models with a ΔAICc lower than 2 but the 95% confidence interval of these variables overlapped zero, we found weak support for MeHg effects on all measures except basal metabolic rate, and for food stress effects on maximum metabolic rate, factorial metabolic scope and feather mass:length ratio. This suggests that MeHg and food stress effects on these measures are statistically identified but not simple and/or were too weak to be detected via linear regression. Overall, combined exposure to ecologically relevant MeHg and unpredictable food stress during the breeding season does not appear to induce extra energetic costs for songbirds in the post-exposure period. However, MeHg effects on molt duration could carry over across multiple annual cycle stages.


Asunto(s)
Metabolismo Energético , Plumas , Compuestos de Metilmercurio , Muda , Estrés Fisiológico , Animales , Plumas/efectos de los fármacos , Compuestos de Metilmercurio/toxicidad , Muda/efectos de los fármacos , Estrés Fisiológico/efectos de los fármacos , Metabolismo Energético/efectos de los fármacos , Gorriones/fisiología , Metabolismo Basal/efectos de los fármacos , Masculino , Estaciones del Año , Femenino
3.
Proc Biol Sci ; 290(1990): 20221909, 2023 01 11.
Artículo en Inglés | MEDLINE | ID: mdl-36629106

RESUMEN

Linking local to regional ecological and evolutionary processes is key to understand the response of Earth's biodiversity to environmental changes. Here we integrate evolution and mutualistic coevolution in a model of metacommunity dynamics and use numerical simulations to understand how coevolution can shape species distribution and persistence in landscapes varying in space and time. Our simulations show that coevolution and species richness can synergistically shape distribution patterns by increasing colonization and reducing extinction of populations in metacommunities. Although conflicting selective pressures emerging from mutualisms may increase mismatches with the local environment and the rate of local extinctions, coevolution increases trait matching among mutualists at the landscape scale, counteracting local maladaptation and favouring colonization and range expansions. Our results show that by facilitating colonization, coevolution can also buffer the effects of environmental changes, preventing species extinctions and the collapse of metacommunities. Our findings reveal the mechanisms whereby coevolution can favour persistence under environmental changes and highlight that these positive effects are greater in more diverse systems that retain landscape connectivity.


Asunto(s)
Biodiversidad , Simbiosis , Extinción Biológica , Fenotipo , Ecosistema
4.
Plant Cell Environ ; 46(9): 2606-2627, 2023 09.
Artículo en Inglés | MEDLINE | ID: mdl-37283560

RESUMEN

The combined study of carbon (C) and oxygen (O) isotopes in plant organic matter has emerged as a powerful tool for understanding plant functional responses to environmental change. The approach relies on established relationships between leaf gas exchange and isotopic fractionation to derive a series of model scenarios that can be used to infer changes in photosynthetic assimilation and stomatal conductance driven by changes in environmental parameters (CO2 , water availability, air humidity, temperature, nutrients). We review the mechanistic basis for a conceptual model, in light of recently published research, and discuss where isotopic observations do not match our current understanding of plant physiological response to the environment. We demonstrate that (1) the model was applied successfully in many, but not all studies; (2) although originally conceived for leaf isotopes, the model has been applied extensively to tree-ring isotopes in the context of tree physiology and dendrochronology. Where isotopic observations deviate from physiologically plausible conclusions, this mismatch between gas exchange and isotope response provides valuable insights into underlying physiological processes. Overall, we found that isotope responses can be grouped into situations of increasing resource limitation versus higher resource availability. The dual-isotope model helps to interpret plant responses to a multitude of environmental factors.


Asunto(s)
Carbono , Oxígeno , Isótopos de Carbono , Isótopos de Oxígeno , Hojas de la Planta/fisiología , Agua
5.
Theor Popul Biol ; 152: 1-22, 2023 08.
Artículo en Inglés | MEDLINE | ID: mdl-37172789

RESUMEN

Predicting the adaptation of populations to a changing environment is crucial to assess the impact of human activities on biodiversity. Many theoretical studies have tackled this issue by modeling the evolution of quantitative traits subject to stabilizing selection around an optimal phenotype, whose value is shifted continuously through time. In this context, the population fate results from the equilibrium distribution of the trait, relative to the moving optimum. Such a distribution may vary with the shape of selection, the system of reproduction, the number of loci, the mutation kernel or their interactions. Here, we develop a methodology that provides quantitative measures of population maladaptation and potential of survival directly from the entire profile of the phenotypic distribution, without any a priori on its shape. We investigate two different systems of reproduction (asexual and infinitesimal sexual models of inheritance), with various forms of selection. In particular, we recover that fitness functions such that selection weakens away from the optimum lead to evolutionary tipping points, with an abrupt collapse of the population when the speed of environmental change is too high. Our unified framework allows deciphering the mechanisms that lead to this phenomenon. More generally, it allows discussing similarities and discrepancies between the two systems of reproduction, which are ultimately explained by different constraints on the evolution of the phenotypic variance. We demonstrate that the mean fitness in the population crucially depends on the shape of the selection function in the infinitesimal sexual model, in contrast with the asexual model. In the asexual model, we also investigate the effect of the mutation kernel and we show that kernels with higher kurtosis tend to reduce maladaptation and improve fitness, especially in fast changing environments.


Asunto(s)
Adaptación Biológica , Modelos Genéticos , Reproducción Asexuada , Genética de Población , Fenotipo , Evolución Biológica , Ambiente
6.
J Eukaryot Microbiol ; 70(6): e12996, 2023.
Artículo en Inglés | MEDLINE | ID: mdl-37577763

RESUMEN

The tropical Andes are a species-rich and nitrogen-limited system, susceptible to increased nitrogen (N) inputs from the atmosphere. However, our understanding of the impacts of increased N input on belowground systems, in particular on protists and their role in nutrient cycling, remains limited. We explored how increased N affects protists in tropical montane rainforests in Ecuador using high-throughput sequencing (HTS) of environmental DNA from two litter layers. In addition, we manipulated the amount of arbuscular mycorrhizal fungi (AMF) and mesofauna, both playing a significant role in N cycling and interacting in complex ways with protist communities. We found that N strongly affected protist community composition in both layers, while mesofauna reduction had a stronger effect on the lower layer. Changes in concentration of the AMF marker lipid had little effect on protists. In both layers, the addition of N increased phagotrophs and animal parasites and decreased plant parasites, while mixotrophs decreased in the upper layer but increased in the lower layer. In the upper layer with higher AMF concentration, mixotrophs decreased, while in the lower layer, photoautotrophs increased and plant parasites decreased. With reduced mesofauna, phagotrophs increased and animal parasites decreased in both layers, while plant parasites increased only in the upper layer. The findings indicate that to understand the intricate response of protist communities to environmental changes, it is critical to thoroughly analyze these communities across litter and soil layers, and to include HTS.


Asunto(s)
Micorrizas , Animales , Micorrizas/genética , Bosque Lluvioso , Nitrógeno , Ecuador , Microbiología del Suelo , Hongos , Eucariontes , Suelo , Plantas
7.
Ann Behav Med ; 57(3): 193-204, 2023 04 05.
Artículo en Inglés | MEDLINE | ID: mdl-35861123

RESUMEN

BACKGROUND: Human activities have changed the environment so profoundly over the past two centuries that human-induced climate change is now posing serious health-related threats to current and future generations. Rapid action from all scientific fields, including behavioral medicine, is needed to contribute to both mitigation of, and adaption to, climate change. PURPOSE: This article aims to identify potential bi-directional associations between climate change impacts and health-related behaviors, as well as a set of key actions for the behavioral medicine community. METHODS: We synthesized the existing literature about (i) the impacts of rising temperatures, extreme weather events, air pollution, and rising sea level on individual behaviors (e.g., eating behaviors, physical activity, sleep, substance use, and preventive care) as well as the structural factors related to these behaviors (e.g., the food system); and (ii) the concurrent positive and negative roles that health-related behaviors can play in mitigation and adaptation to climate change. RESULTS: Based on this literature review, we propose a first conceptual model of climate change and health-related behavior feedback loops. Key actions are proposed, with particular consideration for health equity implications of future behavioral interventions. Actions to bridge the fields of behavioral medicine and climate sciences are also discussed. CONCLUSIONS: We contend that climate change is among the most urgent issues facing all scientists and should become a central priority for the behavioral medicine community.


Asunto(s)
Cambio Climático , Modelos Teóricos , Humanos , Conductas Relacionadas con la Salud
8.
Mol Syst Biol ; 17(12): e10597, 2021 12.
Artículo en Inglés | MEDLINE | ID: mdl-34928547

RESUMEN

To respond to fluctuating conditions, microbes typically need to synthesize novel proteins. As this synthesis relies on sufficient biosynthetic precursors, microbes must devise effective response strategies to manage depleting precursors. To better understand these strategies, we investigate the active response of Escherichia coli to changes in nutrient conditions, connecting transient gene expression to growth phenotypes. By synthetically modifying gene expression during changing conditions, we show how the competition by genes for the limited protein synthesis capacity constrains cellular response. Despite this constraint cells substantially express genes that are not required, trapping them in states where precursor levels are low and the genes needed to replenish the precursors are outcompeted. Contrary to common modeling assumptions, our findings highlight that cells do not optimize growth under changing environments but rather exhibit hardwired response strategies that may have evolved to promote fitness in their native environment. The constraint and the suboptimality of the cellular response uncovered provide a conceptual framework relevant for many research applications, from the prediction of evolution to the improvement of gene circuits in biotechnology.


Asunto(s)
Bacterias , Escherichia coli , Escherichia coli/genética , Fenotipo , Asignación de Recursos
9.
Glob Chang Biol ; 28(22): 6653-6664, 2022 11.
Artículo en Inglés | MEDLINE | ID: mdl-36002985

RESUMEN

Agricultural ecosystems are facing increasing environmental changes. Revealing ecological stability of belowground organisms is key to developing management strategies that maintain agricultural ecosystem services in a changing world. Here, we collected soils from adjacent pairs of maize and rice fields along large spatial scale across Eastern and Southeast China to investigate the importance of core microbiota as a predictor of resistance of soil microbiome (e.g. bacteria, fungi and protist) to climate changes and nutrient fertilization, and their effect on multiple ecosystem functions, representing key services for crop growth and health in agro-ecosystems. Soil microbiome in maize soils exhibited stronger resistance than that in rice soils, by considering multiple aspects of the resistance index, for example, community, phylogenetic conservation and network complexity. Community resistance of soil microbiome showed a geographic pattern, with higher resistance at lower latitudes, suggesting their stronger resistance in warmer regions. Particularly, we highlighted the role of core phylotypes in enhancing the community resistance of soil microbiome, which was essential for the maintenance of multifunctionality in agricultural ecosystems. Our results represent a significant advance in linking core phylotypes to community resistance and ecosystem functions, and therefore forecasting agro-ecosystems dynamics in response to ongoing environmental changes. These suggest that core phylotypes should be considered a key factor in enhancing agricultural sustainability and crop productivity under global change scenarios.


Asunto(s)
Microbiota , Oryza , Agricultura , Ecosistema , Filogenia , Suelo , Microbiología del Suelo , Zea mays
10.
Am J Epidemiol ; 190(10): 2116-2123, 2021 10 01.
Artículo en Inglés | MEDLINE | ID: mdl-33984858

RESUMEN

Urbanization, a major force driving changes in neighborhood environments, may affect residents' health by influencing their daily activity levels. We examined associations of population density changes in urban areas with adults' physical activity changes over 12 years using data from the Australian Diabetes, Obesity and Lifestyle Study (1999-2012). The analytical sample contained 2,354 participants who remained at the same residential address throughout the study period in metropolitan cities and regional cities (42 study areas). Census-based population density measures were calculated for 1-km-radius buffers around their homes. Population density change was estimated using linear growth models. Two-level linear regression models were used to assess associations between changes in population density and changes in self-reported walking and physical activity durations. The average change in population density was 0.8% per year (range, -4.1 to 7.8) relative to baseline density. After adjustment for confounders, each 1% annual increase in population density was associated with 8.5-minutes/week (95% confidence interval: 0.6, 16.4) and 19.0-minutes/week (95% confidence interval: 3.7, 34.4) increases in walking and physical activity, respectively, over the 12-year study period. Increasing population density through urban planning policies of accommodating population growth within the existing urban boundary, rather than expanding city boundaries, could assist in promoting physical activity at the population level.


Asunto(s)
Ejercicio Físico , Conductas Relacionadas con la Salud , Densidad de Población , Características de la Residencia/estadística & datos numéricos , Urbanización/tendencias , Adulto , Australia , Ciudades , Planificación Ambiental , Femenino , Humanos , Modelos Lineales , Estudios Longitudinales , Masculino , Persona de Mediana Edad , Factores de Tiempo , Caminata
11.
Glob Chang Biol ; 27(18): 4392-4402, 2021 Sep.
Artículo en Inglés | MEDLINE | ID: mdl-34089542

RESUMEN

Anthropogenic nitrogen (N) emissions and deposition have been increasing over past decades. However, spatiotemporal variations of N deposition levels and major sources remain unclear in many regions, which hinders making strategies of emission mitigation and evaluating effects of elevated N deposition. By investigating moss N contents and δ15 N values in southwestern (SW) China in 1954-1964, 1970-1994, and 2005-2015, we reconstructed fluxes and source contributions of atmospheric ammonium ( NH 4 + ) and nitrate ( NO 3 - ) deposition and evaluated their historical changes. For urban and non-urban sites, averaged moss N contents did not differ between 1954-1964 and 1970-1994 (1.2%-1.3%) but increased distinctly in 2005-2015 (1.6%-2.3%), and averaged moss δ15 N values decreased from +0.4‰ to +3.3‰ in 1954-1964 to -1.9‰ to -0.7‰ in 1974-1990, and to -4.8‰ to -3.6‰ in 2005-2015. Based on quantitative estimations, N deposition levels from the 1950s to the 2000s did not change in the earlier 20 years but were elevated substantially in the later 30 years. Moreover, the elevation of NH 4 + deposition (by 12.2 kg-N/ha/year at urban sites and 4.6 kg-N/ha/year at non-urban sties) was higher than that of NO 3 - deposition (by 6.0 and 2.9 kg-N/ha/year, respectively) in the later 30 years. This caused a shifted dominance from NO 3 - to NH 4 + in N deposition. Based on isotope source apportionments, contributions of combustion-related NH3 sources (vehicle exhausts, coal combustion, and biomass burning) to the elevation of NH 4 + deposition were two times higher than volatilization NH3 sources (wastes and fertilizers) in the later 30 years. Meanwhile, non-fossil fuel NOx sources (biomass burning, microbial N cycles) contributed generally more than fossil fuel NOx sources (vehicle exhausts and coal combustion) to the elevation of NO 3 - deposition. These results revealed significant contributions of combustion-related NH3 and non-fossil fuel NOx emissions to the historical elevation of N deposition in SW China, which is useful for emission mitigation and ecological effect evaluation of atmospheric N loading.


Asunto(s)
Contaminantes Atmosféricos , Nitrógeno , Contaminantes Atmosféricos/análisis , China , Monitoreo del Ambiente , Nitrógeno/análisis , Estaciones del Año
12.
Environ Monit Assess ; 193(8): 528, 2021 Jul 28.
Artículo en Inglés | MEDLINE | ID: mdl-34322744

RESUMEN

Canalization carried out during petroleum exploration is contributing to environmental changes in the Niger Delta. We carried out a study on five decades of canalization in Olero Creek, Benin River, from 1980 to 2020. The study site covered an area of 36.40 km2. Satellite imageries of five epochs (1980, 1990, 2000, 2010, and 2020) and Shuttle Radar Topographic Mission (SRTM) of 2000, which provided digital elevation models (DEMs) of the study area were collected and analyzed using ERDAS IMAGINE 9.2 and ArcGIS 10.6 software. We found that the total length of dredged canal increased from 14.14 km in 1980 to 61.07 km in 2020, spoil banks doubled from 2.05 km2 in 1980 to 4.13 km2 in 2020, and direct wetland loss doubled from 3.76 km2 in 1980 to 7.57 km2 in 2020, with the largest increase occurring between 1990 and 2000. The land use/land cover, topography, and hydrology of the area also changed. Water bodies that originally accounted for 1.17% of the study area in 1980, increased to 22% in 2020, Rhizophora racemosa fringing the waterbodies increased from 11% in 1980 to 47% in 2020, and Rhizophora mangle decreased from over 55% in 1980 to about 23% in 2020. The results of digital elevation model show that the surface area is undulating with the relative topography of the study site ranging from - 5 to 40 m. We conclude that canalization during petroleum exploration was contributing to land use, topographic, and hydrologic changes in the study area.


Asunto(s)
Hidrología , Petróleo , Benin , Monitoreo del Ambiente , Niger , Ríos , Humedales
13.
Environ Monit Assess ; 193(4): 160, 2021 Mar 04.
Artículo en Inglés | MEDLINE | ID: mdl-33661407

RESUMEN

Human actions often alter natural environments, causing homogenization of micro-habitats and, consequently, the loss or replacement of species. Our research evaluates how the effects of environmental integrity and the physical and chemical characteristics of streams influence the adult Odonata community in a region of the Amazon, in western Pará. The data were obtained in 15 streams of first and second order in the municipality of Santarém, Pará, between October and December 2014 (dry season) and between March and May 2015 (rainy season). A total of 544 specimens were collected, distributed in 23 genera, 35 species. Significant differences were observed in the composition of Odonata based on the integrity of streams, and species are replaced as the habitat integrity gradient is reduced, with species that need more preserved conditions extinct locally, making room for generalist species. However, only Psaironeura tenuissima was an indicator of more preserved sites, while Argia sp.1 and Mnesarete smaragdina were indicative of altered sites. None of the variables had any influence on the richness or abundance of Odonata.


Asunto(s)
Odonata , Animales , Biodiversidad , Ecosistema , Ambiente , Monitoreo del Ambiente , Humanos , Estaciones del Año
14.
Reg Environ Change ; 21(2): 35, 2021.
Artículo en Inglés | MEDLINE | ID: mdl-34720738

RESUMEN

Small-scale fisheries are critically important for livelihoods around the world, particularly in tropical regions. However, climate variability and anthropogenic climate change may seriously impact small-scale fisheries by altering the abundance and distribution of target species. Social relationships between fishery users, such as fish traders, can determine how each individual responds and is affected by changes in fisheries. These informal cooperative and competitive relationships provide access, support, and incentives for fishing and affect the distribution of benefits. Yet, individuals' actions and impacts on individuals are often the primary focus of the economic analyses informing small-scale fisheries' formal management. This focus dismisses relevant social relationships. We argue that this leads to a disconnect between reality and its model representation used in formal management, which may reduce formal fisheries management's efficiency and efficacy and potentially trigger adverse consequences. Here, we examine this argument by comparing the predictions of a simple bioeconomic fishery model with those of a social-ecological model that incorporates the dynamics of cooperative relationships between fish traders. We illustrate model outcomes using an empirical case study in the Mexican Humboldt squid fishery. We find that (1) the social-ecological model with relationship dynamics substantially improves accuracy in predicting observed fishery variables to the simple bioeconomic model. (2) Income inequality outcomes are associated with changes in cooperative trade relationships. When environmental temperature is included in the model as a driver of species production dynamics, we find that climate-driven temperature variability drives a decline in catch that, in turn, reduce fishers' income. We observe an offset of this loss in income by including cooperative relationships between fish traders (oligopoly) in the model. These relationships break down following species distribution changes and result in an increase in prices fishers receive. Finally, (3) our social-ecological model simulations show that the current fishery development program, which seeks to increase fishers' income through an increase in domestic market demand, is supported by predictions from the simple bioeconomic model, may increase income inequality between fishers and traders. Our findings highlight the real and urgent need to re-think fisheries management models in the context of small-scale fisheries and climate change worldwide to encompass social relationship dynamics. SUPPLEMENTARY INFORMATION: The online version contains supplementary material available at (10.1007/s10113-021-01747-5).

15.
Bioessays ; 40(4): e1700137, 2018 04.
Artículo en Inglés | MEDLINE | ID: mdl-29522656

RESUMEN

Cells and tissues are continuously exposed to a changing microenvironment, hence the necessity of a flexible modulation of gene expression that in complex organism have been achieved through specialized chromatin mechanisms. Chromatin-based cell memory enables cells to maintain their identity by fixing lineage specific transcriptional programs, ensuring their faithful transmission through cell division; in particular PcG-based memory system evolved to maintain the silenced state of developmental and cell cycle genes. In evolution the complexity of this system have increased, particularly in vertebrates, indicating combinatorial and dynamic properties of Polycomb proteins, in some cases even overflowing outside the cell nucleus. Therefore, their function may not be limited to the imposition of rigid states of genetic programs, but on the ability to recognize signals and allow plastic transcriptional changes in response to different stimuli. Here, we discuss the most novel PcG mediated memory functions in facing and responding to the challenges posed by a fluctuating environment.


Asunto(s)
Epigénesis Genética/genética , Proteínas del Grupo Polycomb/metabolismo , Animales , Ciclo Celular/genética , Ciclo Celular/fisiología , División Celular/genética , División Celular/fisiología , Cromatina/genética , Cromatina/metabolismo , Proteínas del Grupo Polycomb/genética
16.
Molecules ; 25(17)2020 Sep 03.
Artículo en Inglés | MEDLINE | ID: mdl-32899230

RESUMEN

Terrestrial hot springs are of great interest to the general public and to scientists alike due to their unique and extreme conditions. These have been sought out by geochemists, astrobiologists, and microbiologists around the globe who are interested in their chemical properties, which provide a strong selective pressure on local microorganisms. Drivers of microbial community composition in these springs include temperature, pH, in-situ chemistry, and biogeography. Microbes in these communities have evolved strategies to thrive in these conditions by converting hot spring chemicals and organic matter into cellular energy. Following our previous metagenomic analysis of Pisciarelli hot springs (Naples, Italy), we report here the comparative metagenomic study of three novel sites, formed in Pisciarelli as result of recent geothermal activity. This study adds comprehensive information about phylogenetic diversity within Pisciarelli hot springs by peeking into possible mechanisms of adaptation to biogeochemical cycles, and high applicative potential of the entire set of genes involved in the carbohydrate metabolism in this environment (CAZome). This site is an excellent model for the study of biodiversity on Earth and biosignature identification, and for the study of the origin and limits of life.


Asunto(s)
Manantiales de Aguas Termales/microbiología , Metagenómica , Consorcios Microbianos/genética , ADN/genética , ADN/aislamiento & purificación , Bases de Datos Genéticas , Enzimas/metabolismo , Italia , Metagenoma , Anotación de Secuencia Molecular , Filogenia
17.
Am Nat ; 194(5): 613-626, 2019 11.
Artículo en Inglés | MEDLINE | ID: mdl-31613674

RESUMEN

Evolutionary ecology studies have increasingly focused on the impact of intraspecific variability on population processes. However, the role such variation plays in the dynamics of spatially structured populations and how it interacts with environmental changes remains unclear. Here we experimentally quantify the relative importance of intraspecific variability in dispersal-related traits and spatiotemporal variability of environmental conditions for the dynamics of two-patch metapopulations using clonal genotypes of a ciliate in connected microcosms. We demonstrate that in our simple two-patch microcosms, differences among genotypes are at least as important as spatiotemporal variability of resources for metapopulation dynamics. Furthermore, we show that an important proportion of this effect results from variability of dispersal syndromes. These syndromes can therefore be as important for metapopulation dynamics as spatiotemporal variability of environmental conditions. This study demonstrates that intraspecific variability in dispersal syndromes can be key in the functioning of metapopulations facing environmental changes.


Asunto(s)
Análisis Espacio-Temporal , Tetrahymena thermophila/fisiología , Ecosistema , Genotipo , Modelos Biológicos , Dinámica Poblacional , Tetrahymena thermophila/genética
18.
Mol Phylogenet Evol ; 130: 380-396, 2019 01.
Artículo en Inglés | MEDLINE | ID: mdl-30240912

RESUMEN

Exploring the effects of orographic events and climatic shifts on geographic distribution of organism in the Hengduan Mountains Region (HMR) and its eastern adjacent area is crucial to the understanding of the environmental changes to organismal evolution. To gain further insight into these processes, we reconstruct evolutionary history of ten species in Allium section Sikkimensia, distributed across regions abovementioned. Using chloroplast and nuclear sequence variation of 79 populations of these ten Allium species with known morphological preferences, we elucidate the phylogenetic relationship, divergence time, ancestral area and genetic structures. Climatic variables analysis, Isolation by distance (IBD) and environment (IBE) and Species distribution modeling (SDM) were analyzed along different genetic clades. These analyses indicated that the initial split of Sikkimensia was triggered by climate changes following Qinghai-Tibet Plateau sensu lato (QTPsl) uplift during the late Miocene. Subsequently, divergences within lineage (lineage A)/among lineages (lineage C and D) in Sikkimensia may be induced by the intense uplift of the HMR around 3-4 Ma and abrupt intensifying of the Asian monsoon regimes. Furthermore, Sikkimensia populations exhibited lopsided demographic history in the Last Glacial Maximum (LGM), as was indicated by the expansion of their range in the QDM and contraction in the HMR. Our findings appear to suggest that the HMR uplift could have strengthened the orographic difference between the HMR and its eastern adjacent area and led to a colder climate in the HMR, while geological topography also played an important role for taxa to respond the climate change that had taken place in the HMR and its eastern adjacent area during the Pleistocene.


Asunto(s)
Allium/genética , Evolución Biológica , Ecosistema , China , ADN de Cloroplastos/genética , Variación Genética , Haplotipos/genética , Filogenia , Filogeografía , Tamaño de la Muestra
19.
Glob Chang Biol ; 25(1): 174-186, 2019 01.
Artículo en Inglés | MEDLINE | ID: mdl-30549201

RESUMEN

There is an increasing evidence that smallholder farms contribute substantially to food production globally, yet spatially explicit data on agricultural field sizes are currently lacking. Automated field size delineation using remote sensing or the estimation of average farm size at subnational level using census data are two approaches that have been used. However, both have limitations, for example, automatic field size delineation using remote sensing has not yet been implemented at a global scale while the spatial resolution is very coarse when using census data. This paper demonstrates a unique approach to quantifying and mapping agricultural field size globally using crowdsourcing. A campaign was run in June 2017, where participants were asked to visually interpret very high resolution satellite imagery from Google Maps and Bing using the Geo-Wiki application. During the campaign, participants collected field size data for 130 K unique locations around the globe. Using this sample, we have produced the most accurate global field size map to date and estimated the percentage of different field sizes, ranging from very small to very large, in agricultural areas at global, continental, and national levels. The results show that smallholder farms occupy up to 40% of agricultural areas globally, which means that, potentially, there are many more smallholder farms in comparison with the two different current global estimates of 12% and 24%. The global field size map and the crowdsourced data set are openly available and can be used for integrated assessment modeling, comparative studies of agricultural dynamics across different contexts, for training and validation of remote sensing field size delineation, and potential contributions to the Sustainable Development Goal of Ending hunger, achieve food security and improved nutrition and promote sustainable agriculture.


Asunto(s)
Colaboración de las Masas/estadística & datos numéricos , Granjas , Imágenes Satelitales , Agricultura
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