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1.
Ying Yong Sheng Tai Xue Bao ; 35(4): 1083-1091, 2024 Apr 18.
Artigo em Chinês | MEDLINE | ID: mdl-38884243

RESUMO

We quantified the lag time of vegetation response to drought in the Pearl River basin (PRB) based on the standardized precipitation evapotranspiration index (SPEI) and normalized difference vegetation index (NDVI), and constructed a vegetation loss probability model under drought stress based on the Bayesian theory and two-dimensional joint distribution. We further quantitatively evaluated the spatial variations of loss probability of four vegetation types (evergreen broadleaf forest, mixed forest, grassland, and cropland) under different drought intensities. The results showed that the drought risk in eastern West River, the upper reaches of North River and East River, and southern Pearl River Delta was obviously higher than that in other regions during 1982-2020. The response time of vegetation to drought in high-altitude areas in the upper reaches of PRB (mostly<3 month) was generally shorter than that in low altitude areas (>8 month). Drought exacerbated the probability of vegetation loss, with higher vulnerability of mixed forest than the other three vegetation types. The loss probability of vegetation was lower in northwestern PRB than that in central PRB.


Assuntos
Secas , Ecossistema , Florestas , Rios , Árvores , China , Árvores/crescimento & desenvolvimento , Estresse Fisiológico , Pradaria , Modelos Teóricos , Teorema de Bayes , Poaceae/crescimento & desenvolvimento
2.
Sci Total Environ ; 944: 173925, 2024 Sep 20.
Artigo em Inglês | MEDLINE | ID: mdl-38866162

RESUMO

Climate change and human activities drive widespread shrub encroachment in global grassland ecosystems, particularly in the Eurasian steppe. Caragana shrubs, the primary contributors to shrub encroachment in this region, play a crucial role in shaping the ecosystem's structure and function. Future changes in the suitable distribution range of Caragana species will directly affect the ecological security and sustainable socio-economic development of the Eurasian steppe ecosystem. We used an ensemble modeling approach to predict Caragana shrub-dominated plant communities' current and future distribution in three major steppe subregions: the Black Sea-Kazakhstan steppe, the Tibetan Plateau steppe, and the Central Asian steppe. We assessed the potential risk of Caragana shrub encroachment by predicting changes in the suitable distribution area of 19 Caragana shrub species under future climate changes. Our research findings suggest that the expansion of Caragana species in different subregions of the Eurasian steppe is influenced by the effects of climate change in various ways. The distribution of Caragana species is primarily influenced by precipitation and temperature, and the global human modification (ghm) has a significant impact on the Central Asian and Tibetan Plateau subregions. Minimal changes are expected in the Black Sea-Kazakhstan subregion, a slight increase on the Tibetan Plateau, and a substantial rise in the Central Asian subregion, which suggests a higher potential risk of Caragana species shrub encroachment in that area. Our research provides valuable insights into the response of Caragana shrub encroachment to changing climates and human activities. It also has implications for the sustainable management of different areas of the vast Eurasian steppe ecosystem.


Assuntos
Caragana , Mudança Climática , Pradaria , Monitoramento Ambiental , Ecossistema
3.
J Environ Manage ; 360: 121191, 2024 Jun.
Artigo em Inglês | MEDLINE | ID: mdl-38759552

RESUMO

Understanding the dynamics of urban landscapes and their impacts on ecological well-being is crucial for developing sustainable urban management strategies in times of rapid urbanisation. This study assesses the nature and drivers of the changing urban landscape and ecosystem services in cities located in the rainforest (Akure and Owerri) and guinea savannah (Makurdi and Minna) of Nigeria using a combination of remote sensing and socioeconomic techniques. Landsat 8 datasets provided spatial patterns of the normalised difference vegetation index (NDVI) and normalised difference built-up index (NDBI). A household survey involving the administration of a semi-structured questionnaire to 1552 participants was conducted. Diminishing NDVI and increasing NDBI were observed due to the rising trend of urban expansion, corroborating the perception of over 54% of the respondents who noted a decline in landscape ecological health. Residential expansion, agricultural practices, transport and infrastructural development, and fuelwood production were recognised as the principal drivers of landscape changes. Climate variability/change reportedly makes a 28.5%-34.4% (Negelkerke R2) contribution to the changing status of natural landscapes in Akure and Makurdi as modelled by multinomial logistic regression, while population growth/in-migration and economic activities reportedly account for 19.9%-36.3% in Owerri and Minna. Consequently, ecosystem services were perceived to have declined in their potential to regulate air and water pollution, reduce soil erosion and flooding, and mitigate urban heat stress, with a corresponding reduction in access to social services. We recommend that urban residents be integrated into management policies geared towards effectively developing and enforcing urban planning regulations, promoting urban afforestation, and establishing sustainable waste management systems.


Assuntos
Ecossistema , Floresta Úmida , Nigéria , Conservação dos Recursos Naturais , Pradaria , Humanos , Urbanização , Guiné
4.
Planta ; 260(1): 2, 2024 May 18.
Artigo em Inglês | MEDLINE | ID: mdl-38761315

RESUMO

MAIN CONCLUSION: Leaf vein network cost (total vein surface area per leaf volume) for major veins and vascular bundles did not differ between monocot and dicot species in 21 species from the eastern Colorado steppe. Dicots possessed significantly larger minor vein networks than monocots. Across the tree of life, there is evidence that dendritic vascular transport networks are optimized, balancing maximum speed and integrity of resource delivery with minimal resource investment in transport and infrastructure. Monocot venation, however, is not dendritic, and remains parallel down to the smallest vein orders with no space-filling capillary networks. Given this departure from the "optimized" dendritic network, one would assume that monocots are operating at a significant energetic disadvantage. In this study, we investigate whether monocot venation networks bear significantly greater carbon/construction costs per leaf volume than co-occurring dicots in the same ecosystem, and if so, what physiological or ecological advantage the monocot life form possesses to compensate for this deficit. Given that venation networks could also be optimized for leaf mechanical support or provide herbivory defense, we measured the vascular system of both monocot and dicots at three scales to distinguish between leaf investment in mechanical support (macroscopic vein), total transport and capacitance (vascular bundle), or exclusively water transport (xylem) for both parallel and dendritic venation networks. We observed that vein network cost (total vein surface area per leaf volume) for major veins and vascular bundles was not significantly different between monocot species and dicot species. Dicots, however, possess significantly larger minor vein networks than monocots. The 19 species subjected to gas-exchange measurement in the field displayed a broad range of Amax and but demonstrated no significant relationships with any metric of vascular network size in major or minor vein classes. Given that monocots do not seem to display any leaf hydraulic disadvantage relative to dicots, it remains an important research question why parallel venation (truly parallel, down to the smallest vessels) has not arisen more than once in the history of plant evolution.


Assuntos
Folhas de Planta , Folhas de Planta/anatomia & histologia , Colorado , Feixe Vascular de Plantas/anatomia & histologia , Feixe Vascular de Plantas/fisiologia , Xilema/anatomia & histologia , Xilema/fisiologia , Pradaria , Magnoliopsida/fisiologia , Magnoliopsida/anatomia & histologia , Carbono/metabolismo , Ecossistema
5.
Sci Rep ; 14(1): 5489, 2024 03 06.
Artigo em Inglês | MEDLINE | ID: mdl-38448478

RESUMO

Ecological compensation has emerged as a crucial institutional framework for managing the interplay between ecological preservation and economic development in China. This study focuses on the specific case of grassland ecological compensation to investigate the protection of rights and interests of non-governmental subjects. By utilizing data derived from questionnaire responses, this study examines the legal rights, obligations, and responsibilities associated with grassland ecological compensation. Statistical techniques such as Z-distribution, chi-square test, and non-parametric measures of correlation are employed to analyze the collected data, which are presented using tables and graphs. Furthermore, this research evaluates the current state of rights and interests of compensation subjects engaged in ecological compensation practices, aiming to enhance our comprehension and assessment of the extent to which the ecological compensation system safeguards the rights and interests of individuals. The findings show that a substantial number of respondents see current grassland ecological compensation methods in China as reasonable but insufficient, indicating a need for method diversification. There's a clear preference for a shared responsibility model over government-only funding, especially in regions with large grassland areas. This highlights the necessity for adaptable laws and a legal framework that accommodates diverse stakeholder needs. Additionally, the importance of clear property rights is emphasized for sustainable land use. The study suggests legislative reform towards a more equitable and effective approach to grassland conservation, providing valuable recommendations for refining and advancing the ecological compensation system.Author name 1 (Ziqi Liu) mismatch between ms and metadata. We have foolowed metadata. Kindly check and confirm.The metadata is right. Thank you.


Assuntos
Desenvolvimento Econômico , Pradaria , Humanos , China , Coleta de Dados , Ecossistema
6.
New Phytol ; 241(6): 2410-2422, 2024 Mar.
Artigo em Inglês | MEDLINE | ID: mdl-38214451

RESUMO

Uncertainty persists within trait-based ecology, partly because few studies assess multiple axes of functional variation and their effect on plant performance. For 55 species from two semiarid grasslands, we quantified: (1) covariation between economic traits of leaves and absorptive roots, (2) covariation among economic traits, plant height, leaf size, and seed mass, and (3) relationships between these traits and species' abundance. Pairs of analogous leaf and root traits were at least weakly positively correlated (e.g. specific leaf area (SLA) and specific root length (SRL)). Two pairs of such traits, N content and DMC of leaves and roots, were at least moderately correlated (r > 0.5) whether species were grouped by site, taxonomic group and growth form, or life history. Root diameter was positively correlated with seed mass for all groups of species except annuals and monocots. Species with higher leaf dry matter content (LDMC) tended to be more abundant (r = 0.63). Annuals with larger seeds were more abundant (r = 0.69). Compared with global-scale syntheses with many observations from mesic ecosystems, we observed stronger correlations between analogous leaf and root traits, weaker correlations between SLA and leaf N, and stronger correlations between SRL and root N. In dry grasslands, plant persistence may require coordination of above- and belowground traits, and dense tissues may facilitate dominance.


Assuntos
Ecossistema , Pradaria , Ecologia , Sementes , Plantas , Folhas de Planta
7.
Sci China Life Sci ; 67(2): 403-413, 2024 Feb.
Artigo em Inglês | MEDLINE | ID: mdl-37606847

RESUMO

Global climate change has led to the decline of species and functional diversity in ecosystems, changing community composition and ecosystem functions. However, we still know little about how species with different resource-use strategies (different types of resource usage and plant growth of plants as indicated by the spectrum of plant economic traits, including acquisitive resource-use strategy and conservative resource-use strategy) would change in response to climate change, and how the changes in the diversity of species with different resource-use strategies may influence community-level productivity. Here, using long-term (1982-2017) observatory data in a temperate grassland in Inner Mongolia, we investigated how climate change had affected the species richness (SR) and functional richness (FRic) for the whole community and for species with different resource-use strategies. Specifically, based on data for four traits representing leaf economics spectrum (leaf carbon concentration, leaf nitrogen concentration, leaf phosphorus concentration, and specific leaf area), we divided 81 plant species appearing in the grassland community into three plant functional types representing resource-acquisitive, medium, and resource-conservative species. We then analyzed the changes in community-level productivity in response to the decline of SR and FRic at the community level and for different resource-use strategies. We found that community-level SR and FRic decreased with drying climate, which was largely driven by the decline of diversity for resource-acquisitive species. However, community-level productivity remained stable because resource-conservative species dominating this grassland were barely affected by climate change. Our study revealed distinctive responses of species with different resource-use strategies to climate change and provided a new approach based on species functional traits for predicting the magnitude and direction of climate change effects on ecosystem functions.


Assuntos
Ecossistema , Pradaria , Mudança Climática , Plantas , China , Biodiversidade
8.
Sci Total Environ ; 912: 169358, 2024 Feb 20.
Artigo em Inglês | MEDLINE | ID: mdl-38135064

RESUMO

Grazing exclusion has been implemented worldwide as a nature-based solution for restoring degraded grassland ecosystems that arise from overgrazing. However, the effect of grazing exclusion on soil nitrogen cycle processes, subsequent greenhouse gas emissions and underlying mechanisms remain unclear. Here, we investigated the effect of four-year grazing exclusion on plant communities, soil properties, and soil nitrogen cycle-related functional gene abundance in an alpine meadow on the Qinghai-Tibet Plateau. Using an automated continuous-flow incubation system, we performed an incubation experiment and measured soil-borne N2O, N2, and CO2 fluxes to three successive "hot moment" events (precipitation, N deposition, and oxic-to-anoxic transition) between grazing-excluded and grazing soil. Higher soil N contents (total nitrogen, NH4+, NO3-) and extracellular enzyme activities (ß-1,4-glucosidase, ß-1,4-N-acetyl-glucosaminidase, cellobiohydrolase) are observed under grazing exclusion. The aboveground and litter biomass of plant community was significantly increased by grazing exclusion, but grazing exclusion decreased the average number of plant species and microbial diversity. The N2O + N2 fluxes observed under grazing exclusion were higher than those observed under free grazing. The N2 emissions and N2O/(N2O + N2) ratios observed under grazing exclusion were higher than those observed under free grazing in oxic conditions. Instead, higher N2O fluxes and lower denitrification functional gene abundances (nirS, nirK, nosZ, and nirK + nirS) under anoxia were found under grazing exclusion than under free grazing. The N2O site-preference value indicates that under grazing exclusion, bacterial denitrification contributes more to higher N2O production compared with under free grazing (81.6 % vs. 59.9 %). We conclude that grazing exclusion could improve soil fertility and plant biomass, nevertheless it may lower plant and microbial diversity and increase potential N2O emission risk via the alteration of the denitrification end-product ratio. This indicates that not all grassland management options result in a mutually beneficial situation among wider environmental goals such as greenhouse gas mitigation, biodiversity, and social welfare.


Assuntos
Desnitrificação , Gases de Efeito Estufa , Tibet , Ecossistema , Pradaria , Solo , Microbiologia do Solo , Óxido Nitroso/análise
9.
Braz. j. biol ; 84: e253215, 2024. tab
Artigo em Inglês | LILACS, VETINDEX | ID: biblio-1360216

RESUMO

Frequencies, magnitudes, and distributions of occurrence can affect the events. The problem can be worse or the solution better if greater frequencies and magnitudes are presented with aggregated distribution in the production system. Indices, hence, are used to assist in decision-making on certain issues. The system formed by Caryocar brasiliense Camb. (Malpighiales: Caryocaraceae), a typical and economically important Brazilian Cerrado tree species, and its several arthropods are adequate to evaluate a new index. This study aimed to test an index to identify the loss and solution sources and their importance in the system's loss or income gain. The index is: Percentage of Importance Indice [...] separated the loss sources [e.g., Edessa rufomarginata De Geer, 1773 (Hemiptera: Pentatomidae) on fruits = 41.90%)] on the percentage of reduction of fruit production (e.g., 0.13%), calculated the attention level (e.g., 0.10/fruit), with a total lost production of 1.35% (≈ 307 total lost fruits). The % I.I. also separated the solution sources [e.g., Zelus armillatus (Lep. and Servi., 1825) (Hemiptera: Reduviidae) = 55.48%), the non-attention level (e.g., Z. armillatus: 0.394 for E. rufomarginata on fruit), with total income gain of 0.56% (≈ 128 total saved fruits) on the natural system (e.g., C. brasiliense trees). This index can calculate losses or the effectiveness of the solutions monetarily. Here I test the % I.I., an index that can detect the key loss and solution sources on the system, which can be applied in some knowledge areas.


Frequências, magnitudes e distribuição de ocorrência pode afetar os eventos. O problema pode ser pior ou a solução melhor se maiores frequências e magnitudes forem apresentadas com distribuição agregada no sistema de produção. Índices, então, são usados para assistir na decisão de certas questões. O sistema formado pelo Caryocar brasiliense Camb. (Malpighiales: Caryocaraceae), uma espécie arbórea típica e economicamente importante do Cerrado brasileiro, e seus diversos artrópodes são adequados para avaliar um novo índice. A motivação deste trabalho foi testar um índice capaz de identificar as fontes de perda e de soluções, e suas importâncias em termos de perdas ou ganhos no sistema. O índice é: percentagem de importância [...] separou as fontes de perda [ex., Edessa rufomarginata De Geer, 1773 (Hemiptera: Pentatomidae) em frutos = 41,90%)] na percentagem de redução na produção de frutos (ex., 0,13%), calculando o nível de atenção (ex., 0,10/fruto), com um total de perda de produção de 1,35% (≈ 307 frutos totais perdidos). O % I.I. também separou as fontes de solução [ex., Zelus armillatus (Lep. and Servi., 1825) (Hemiptera: Reduviidae) = 55,48%)], o nível de não atenção (ex., Z. armillatus: 0,394 para E. rufomarginata em fruto), com total de ganho de 0,56% (≈ 128 total de frutos salvos) no sistema natural (ex., árvores de C. brasiliense). Esse índice pode calcular essas perdas ou a eficácia das soluções monetariamente. Aqui eu testo o % I.I., um índice capaz de detectar fatores chaves de perda e de soluções no sistema, capaz de ser aplicado em algumas áreas do conhecimento.


Assuntos
Artrópodes , Brasil , Pradaria , Economia , Malpighiales
10.
New Phytol ; 240(5): 2035-2049, 2023 Dec.
Artigo em Inglês | MEDLINE | ID: mdl-37691273

RESUMO

Recent studies on root traits have shown that there are two axes explaining trait variation belowground: the collaboration axis with mycorrhizal partners and the conservation ('fast - slow') axis. However, it is yet unknown whether these trait axes affect the assembly of soilborne fungi. We expect saprotrophic fungi to link to the conservation axis of root traits, whereas pathogenic and arbuscular mycorrhizal fungi link to the collaboration axis, but in opposite directions, as arbuscular mycorrhizal fungi might provide pathogen protection. To test these hypotheses, we sequenced rhizosphere fungal communities and measured root traits in monocultures of 25 grassland plant species, differing in age. Within the fungal guilds, we evaluated fungal species richness, relative abundance and community composition. Contrary to our hypotheses, fungal diversity and relative abundance were not strongly related to the root trait axes. However, saprotrophic fungal community composition was affected by the conservation gradient and pathogenic community composition by the collaboration gradient. The rhizosphere AMF community composition did not change along the collaboration gradient, even though the root trait axis was in line with the root mycorrhizal colonization rate. Overall, our results indicate that in the long term, the root trait axes are linked with fungal community composition.


Assuntos
Micorrizas , Rizosfera , Raízes de Plantas/microbiologia , Pradaria , Micorrizas/fisiologia , Plantas/microbiologia , Fungos/fisiologia , Microbiologia do Solo , Solo
11.
J Environ Manage ; 345: 118797, 2023 Nov 01.
Artigo em Inglês | MEDLINE | ID: mdl-37591103

RESUMO

Conserving plant species diversity is crucial to the sustainable development of human beings. Nevertheless, the trends toward declining species numbers and homogenization of species distributions have become increasingly evident. The monetary value of species diversity can make stakeholders put more serious attentions on the protection of species diversity, but which is difficult to evaluate. This paper combined survey data and ecological data obtained through plot sampling and geographic information system methods, to assess the value of plant species diversity in permanent grasslands for local herders who are the direct users of grasslands, and whose livelihoods and well-beings are tightly related with the ecosystem of grasslands. Based on the life satisfaction approach, we found that the monetary value of one plant species for each herder household is equivalent to 9.8% of the annual household income on average, which increases to 15.9% when the level of species evenness is higher. The results of a heterogeneity analysis revealed that the value of plant species diversity varies significantly among different groups of households. Our research introduced a new method to quantify the value of species diversity for stakeholders. The estimation of monetary value of plant species diversity will have far-reaching influence on stakeholders and policymakers involved in protecting species diversity of permanent grasslands.


Assuntos
Ecossistema , Pradaria , Humanos , Biodiversidade , Plantas , Desenvolvimento Sustentável
12.
Nature ; 620(7973): 358-365, 2023 Aug.
Artigo em Inglês | MEDLINE | ID: mdl-37468624

RESUMO

Archaeogenetic studies have described two main genetic turnover events in prehistoric western Eurasia: one associated with the spread of farming and a sedentary lifestyle starting around 7000-6000 BC (refs. 1-3) and a second with the expansion of pastoralist groups from the Eurasian steppes starting around 3300 BC (refs. 4,5). The period between these events saw new economies emerging on the basis of key innovations, including metallurgy, wheel and wagon and horse domestication6-9. However, what happened between the demise of the Copper Age settlements around 4250 BC and the expansion of pastoralists remains poorly understood. To address this question, we analysed genome-wide data from 135 ancient individuals from the contact zone between southeastern Europe and the northwestern Black Sea region spanning this critical time period. While we observe genetic continuity between Neolithic and Copper Age groups from major sites in the same region, from around 4500 BC on, groups from the northwestern Black Sea region carried varying amounts of mixed ancestries derived from Copper Age groups and those from the forest/steppe zones, indicating genetic and cultural contact over a period of around 1,000 years earlier than anticipated. We propose that the transfer of critical innovations between farmers and transitional foragers/herders from different ecogeographic zones during this early contact was integral to the formation, rise and expansion of pastoralist groups around 3300 BC.


Assuntos
Agricultura , Civilização , Pradaria , Animais , Humanos , Agricultura/economia , Agricultura/história , Ásia , Civilização/história , Domesticação , Europa (Continente) , Fazendeiros/história , História Antiga , Cavalos , Comportamento Sedentário/história , Invenções/economia , Invenções/história
13.
J Environ Manage ; 343: 118225, 2023 Oct 01.
Artigo em Inglês | MEDLINE | ID: mdl-37244103

RESUMO

Forest-grassland ecotones are a mosaic of grassland, savanna, and upland forest. As such, landowners may have opportunities to choose to manage their lands for multiple objectives. We estimated the economic returns from managing forest and rangeland in southeastern Oklahoma, USA to produce different combinations of timber, cattle forage, and white-tailed deer (Odocoileus virginianus Zimmermann) browse for a 40-year period. We further conducted a survey to understand landowner perceptions of obstacles to adopting active management that involve timber harvest and prescribed fire. The highest net return was obtained from the treatment with harvested timber that was burned every four years (uneven-aged woodland/forest) because it had the greatest gross return from a combination of timber (46%), cattle forage (42%), and deer browse (11%). The return from this treatment was greater than that for managed for timber only (closed-canopy forest) or prioritizing cattle and deer (savanna). Survey results suggested that landowners were aware of the benefits of active management but that the majority (66%) considered cost a major obstacle in the management of their forest or rangeland. In particular, women forestland owners and older landowners considered cost an obstacle. Our findings advocate integrated timber, cattle, and deer management as the best economic strategy within the forest-grassland ecotone and for targeted outreach and landowner education related to the benefits of active management.


Assuntos
Cervos , Animais , Feminino , Bovinos , Pradaria , Florestas , Software
14.
Can Rev Sociol ; 60(3): 479-501, 2023 08.
Artigo em Inglês | MEDLINE | ID: mdl-37073548

RESUMO

In this paper, we examine the intersections of parental support and family socioeconomic background within an undergraduate sample (N = 596) in a mid-sized Canadian Prairie city. Coresidence, financial support, and parental and professional financial advice are examined as types of 'family capital' that may be distributed unequally across socioeconomic groups. In keeping with previous literature, findings showed that students whose parents had university education and higher incomes received more robust coverage of their housing and school expenses. Students whose parents were university-educated were also more likely to be living with a parent, though no relationship was found between parental income and coresidence. Contrasting with previous literature, few relationships were found between socioeconomic background and receipt or influence of financial advice. These results contribute to the literature by generalising claims about family capital to a Canadian student sample, where relatively few studies have empirically examined intergenerational transfers as mechanisms for transmitting privilege during the transition to adulthood. With increasing demands for higher education and simultaneous declines in government subsidisation of its costs, disparate access to family capital is likely to intensify the reproduction of social inequality across generations.


Dans cet article, nous examinons les intersections entre le soutien parental et les antécédents socioéconomiques de la famille au sein d'un échantillon d'étudiants de premier cycle (N = 596) dans une ville canadienne de taille moyenne des Prairies. La coresidence, le soutien financier et les conseils financiers parentaux et professionnels sont examinés en tant que types de ' capital familial ' susceptibles d'être répartis de manière inégale entre les groupes socioéconomiques. Conformément à la littérature antérieure, les résultats ont montré que les étudiants dont les parents ont fait des études universitaires et ont des revenus plus élevés bénéficient d'une couverture plus solide de leurs frais de logement et de scolarité. Les étudiants dont les parents ont fait des études universitaires sont également plus susceptibles de vivre avec un parent, bien qu'aucune relation n'ait été établie entre le revenu des parents et la coresidence. Contrairement à la littérature précédente, peu de liens ont été établis entre le milieu socio-économique et l'obtention ou l'influence des conseils financiers. Ces résultats contribuent à la littérature en généralisant les affirmations sur le capital familial à un échantillon d'étudiants canadiens, où relativement peu d'études ont examiné empiriquement les transferts intergénérationnels en tant que mécanismes de transmission des privilèges pendant la transition vers l'âge adulte. Avec l'augmentation de la demande d'enseignement supérieur et la diminution simultanée des subventions gouvernementales pour ses coûts, l'accès disparate au capital familial est susceptible d'intensifier la reproduction de l'inégalité sociale entre les générations.


Assuntos
Pradaria , Pais , Humanos , Canadá , Fatores Socioeconômicos , Estudantes , Apoio Financeiro
15.
Braz J Biol ; 83: e272087, 2023.
Artigo em Inglês | MEDLINE | ID: mdl-37075434

RESUMO

Heavy metal toxicity is becoming an increasing concern for environmental, human and animal health. The current research analyzed the lead (Pb) contamination in the food chain under three different irrigation sources (ground, canal, and wastewater). Soil, plant and animal samples were collected from the Jhang district of Pakistan and processed with an atomic absorption spectrophotometer. Lead concentration varied in the samples as: 5.22-10.73 mg/kg in soil, 2.46-10.34 mg/kg in forages and 0.736-2.45 mg/kg in animal samples. The observed lead concentration in forage and animal blood samples was higher than the standard limits. The pollution load index (0.640-1.32) in soil showed that lead contamination mainly took place at the wastewater irrigating sites. Bio-concentration factor values (0.313-1.15) were lower than one in all samples except Zea mays, showing that lead metal was actively taken up by Zea mays tissues from the soil. Enrichment factor values ranged from 0.849-3.12, showing a moderate level of lead enrichment. Daily intake and health risk index varied between 0.004-0.020 mg/kg/day and 0.906-4.99, respectively. All the samples showed maximum lead concentration at the wastewater irrigating site compared to the ground or canal water application sites. These results recommended that consistent application of wastewater for forage irrigation must be avoided to prevent health hazards associated with lead in the animal and human food chain. Government must implement adequate strategies to protect the animal and human health from the harms of toxic heavy metals.


Assuntos
Metais Pesados , Poluentes do Solo , Humanos , Animais , Chumbo , Solo , Metais Pesados/análise , Gado , Águas Residuárias , Pradaria , Poluentes do Solo/toxicidade , Poluentes do Solo/análise , Medição de Risco , Monitoramento Ambiental/métodos
16.
Environ Entomol ; 52(2): 279-285, 2023 04 18.
Artigo em Inglês | MEDLINE | ID: mdl-36745143

RESUMO

Habitat fragmentation is considered an important threat to biodiversity, increasing species exposure to edge effects. The Brazilian Cerrado savanna is considered a biodiversity hotspot and has been converted to small, isolated fragments due to human activities. Ant communities and colony survivorship are known to be affected by edge effects in Cerrado, but to date there is no information on the genetic diversity of ant colonies at the edge of fragmented areas. Here, we investigate if colony genetic diversity and structure of Odontomachus chelifer (Latreille) ants (Hymenoptera: Formicidae) are subject to edge effects in a Cerrado reserve in southeast Brazil. Using microsatellites, we evaluated the number of breeders (queens and males) and the genetic diversity in O. chelifer colonies located in the interior versus edge of a Cerrado fragment. All O. chelifer nests had multiple queens, which presented a low mating frequency. The number of breeders and most estimates of genetic diversity did not differ between colonies at the edge versus interior of the fragment. Genetic structure was not influenced by nest location as well. However, we detected a small and positive increase in the observed heterozygosity in colonies located at fragment edges. High heterozygosity is thought to be particularly important in fast-changing environments, such as edges, providing an advantage for genetic diversity. Further investigation is needed to assess in greater detail how habitat loss affects O. chelifer biology. Our study is a first step toward elucidating edge effects on genetic diversity of ant colonies, a topic still poorly explored in tropical environments.


Assuntos
Formigas , Humanos , Animais , Formigas/genética , Pradaria , Brasil , Ecossistema , Variação Genética
17.
Environ Sci Pollut Res Int ; 30(17): 50549-50566, 2023 Apr.
Artigo em Inglês | MEDLINE | ID: mdl-36792859

RESUMO

Several studies have identified deforestation as a major cause of environmental degradation, but little is known about the asymmetric effect of the environmental cost of forest rents. To fill this gap, our study uses the nonlinear autoregressive distributed lag (NARDL) model and asymmetric causality test to examine the environmental implication of forest rents in the Guinean Forest-Savanna Mosaic of Nigeria over the period 1990:Q1 to 2016:Q4. The empirical results show that forest rents increase CO2 emissions when the shock to forest rents is positive and decreases CO2 emissions when the shock to forest rents is negative. The results further show evidence of asymmetric effects of crop production, fossil fuel energy consumption, and economic growth on CO2 emissions. Moreover, the effects of both positive and negative shocks in economic growth are elastic, suggesting that CO2 emissions respond in a larger magnitude to a 1% positive or negative shock in economic growth. While the positive shock to crop production and economic growth stimulates CO2 emissions, their negative shocks dampen CO2 emissions. In addition, the positive (negative) shocks to fossil energy consumption exert upward (downward) pressure on CO2 emissions. Furthermore, the asymmetric causality test divulges that a positive change in forest rents causes a negative change in CO2 emissions and a negative change in forest rents causes a positive change in CO2 emissions. Based on these findings, the study recommends the need for policymakers to formulate sound policies to protect the forests and transit toward clean energy consumption to minimize energy-related CO2 emissions in the country.


Assuntos
Dióxido de Carbono , Pradaria , Dióxido de Carbono/análise , Papua Nova Guiné , Desenvolvimento Econômico , Fontes Geradoras de Energia
18.
Artigo em Inglês | MEDLINE | ID: mdl-36674129

RESUMO

Soil moisture plays an important role in ecology, hydrology, agriculture and climate change. This study proposes a soil moisture prediction model, based on the depth and water balance equation, which integrates the water balance equation with the seasonal ARIMA model, and introduces the depth parameter to consider the soil moisture at different depths. The experimental results showed that the model proposed in this study was able to provide a higher prediction accuracy for the soil moisture at 40 cm, 100 cm and 200 cm depths, compared to the seasonal ARIMA model. Different models were used for different depths. In this study, the seasonal ARIMA model was used at 10 cm, and the proposed model was used at 40 cm, 100 cm and 200 cm, from which more accurate prediction values could be obtained. The fluctuation of the predicted data has a certain seasonal trend, but the regularity decreases with the increasing depth until the soil moisture is almost independent of the external influence at a 200 cm depth. The accurate prediction of the soil moisture can contribute to the scientific management of the grasslands, thus promoting ecological stability and the sustainable development of the grasslands while rationalizing land use.


Assuntos
Pradaria , Solo , Água/análise , Agricultura/métodos , Desenvolvimento Sustentável , China
19.
Environ Manage ; 71(2): 405-420, 2023 02.
Artigo em Inglês | MEDLINE | ID: mdl-36471000

RESUMO

Clarifying the behavior motivation of herders participating in grassland governance has important theoretical and practical significance for the construction of ecological civilization and economic development in pastoral areas. Based on the data from 425 households in the Inner Mongolia Autonomous Region, this paper constructs a Double-Hurdle model to explore the impact of informal institutions and environmental emotion (individual emotion, collective emotion, and intergenerational dependence) on herders' grassland governance. The results show that informal institutions promote herders' willingness and payment for participating in grassland governance, and collective emotions hinder herders' participation, showing a "free-ride" mentality. Informal institutions moderate the relationship between collective emotions and grassland governance behavior. Informal institutions also help herders understand the collective sense of responsibility and morality behind grassland protection, thereby reducing the "free-ride" mentality. Therefore, it is necessary to maintain the informal institutions' role as a "glue" in the traditional culture of pastoral areas and to promote the realization of policy goals.


Assuntos
Conservação dos Recursos Naturais , Pradaria , Motivação , China , Humanos
20.
J Environ Manage ; 327: 116883, 2023 Feb 01.
Artigo em Inglês | MEDLINE | ID: mdl-36455444

RESUMO

Grassland degradation has caused increasingly prominent conflict between ecological environment conservation and socioeconomic development in the Qilian Mountains, China. How to effectively trade-offs and synergies to ecological and socioeconomic is essential to achieving the sustainable development of the grassland ecosystem. However, few studies have addressed the trade-offs and synergies of grassland ecosystem services in terms of coupling the natural ecosystem and the socioeconomic system. Therefore, we constructed an index of the analyzed trade-offs and synergies of grassland ecosystem services from the perspective of "ecological-production-living" functions (EPLFs) and analyzed the spatial-temporal characteristics of grassland EPLF trade-off and synergy relationships based on the data from the implementation of three conservation policies in the Qilian Mountains from 2003 to 2020. The results showed evident spatial and temporal differentiation of the grassland EPLFs. The ecological function was consistent with the production function, trending upward initially and then decreasing. The living function showed a trend of continuous increase. The spatial pattern of grassland EPLFs showed that the northwest and southeast were more active than the middle of the Qilian Mountains, and the regional gradient difference was apparent. The trade-off and synergy relationships of grassland EPLFs have obvious spatial correlations as well; spatial differences were evident under different conservation policies. With national park construction, the synergistic relationship gradually weakened and the trade-off relationship gradually strengthened. These results suggest that the policy of ecological priority increased trade-offs and reduced synergies among EPLFs was not conducive to coupling and coordinating grassland EPLFs for development in the Qilian Mountains. Our study also demonstrates that maintaining moderate grassland grazing pressure and the appropriate number of herdsmen is crucial to sustainably develop the grassland ecosystem in the Qilian Mountains, and further research into coupling mechanisms for grassland EPLFs is needed to reduce trade-offs and increase synergies with grassland ecosystem services.


Assuntos
Ecossistema , Pradaria , Conservação dos Recursos Naturais , Desenvolvimento Sustentável , China
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