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Nativa ◽  
2021 ◽  
Vol 9 (5) ◽  
pp. 588-593
Author(s):  
Aguinaldo Joaquim Mário ◽  
Sailon Augusto Roia Mesa ◽  
Caetano Miguel Lemos Serrote

O estudo foi realizado na Reserva Florestal de Mecubúri, em Moçambiquee, visando avaliar os efeitos das atividades antrópicas sobre a cobertura florestal. Áreas de queimada, agrícola e de exploração florestal foram comparadas com uma área controle em termos de composição e fitossociologia. Em cada área, foram estabelecidas, de maneira sistemática, parcelas quadrangulares de 20 x 20 m, distantes 20 m uma da outra, sendo realizado o levantamento da vegetação adulta e da regeneração. Foram determinados índices de similaridade, diversidade e riqueza. Os resultados indicaram existir dissimilaridade entre as áreas, sendo que as espécies Julbernardia globiflora, Diplorhynchus condylocarpon, Brachystegia utilis, Millettia stuhlmannii, Afzelia quanzensis, Burkea africana e Cussonia arborea destacaram-se em termos de abundância, frequência, dominância, Índice de Valor de Importância (IVI) e regeneração. O maior número de árvores por hectare foi encontrado na área de controle e o menor número foi encontrado na área agrícola. Com base no índice de dispersão de Morisita, a maior parte das espécies distribui-se de forma aleatória e agrupada. A distribuição diamétrica das árvores seguiu o padrão de J-invertido, característico de florestas naturais.  As práticas de queimadas, agricultura e exploração florestal contribuem na redução da cobertura florestal na Reserva Florestal de Mecubúri. Palavras-chave: fitossociologia; conservação; desmatamento.   The effect of anthropic activities on forest coverage in the Mecubúri Forest Reserve, Mozambique   ABSTRACT: The study was carried out in the Mecubúri Forest Reserve, Mozambique, with the purpose of evaluating the effects of human activities on the forest cover. Burning, agricultural and logging areas were compared with a control area in terms of composition and phytosociology. In each area were systematically established 20 x 20 m quadrangular plots, 20 m apart from each other, in which were carried out the survey of adult vegetation and regeneration. The similarity, diversity and richness indices were determined. The results showed that there is dissimilarity between the areas and the species Julbernardia globiflora, Diplorhynchus condylocarpon, Brachystegia utilis, Millettia stuhlmannii, Afzelia quanzensis, Burkea africana e Cussonia arborea stood out in terms of abundance, frequency, dominance, Importance Value Index (IVI) and regeneration. The largest number of trees per hectare was found in the control area, and the smallest number was found in the agricultural area. Based on the Morisita dispersion index, most species have random and clustered distribution. The diametric structure of the trees followed the inverted-j, typical of natural forests. Burning, agriculture and logging contribute to the reduction of forest cover in the Mecubúri Forest Reserve. Keywords: phytosociology; conservation; deforestation.


Water ◽  
2021 ◽  
Vol 13 (22) ◽  
pp. 3189
Author(s):  
Iurii Kolesnichenko ◽  
Larisa G. Kolesnichenko ◽  
Sergey N. Vorobyev ◽  
Liudmila S. Shirokova ◽  
Igor P. Semiletov ◽  
...  

In order to foresee possible changes in the elementary composition of Arctic river waters, complex studies with extensive spatial coverage, including gradients in climate and landscape parameters, are needed. Here, we used the unique position of the Ob River, draining through the vast partially frozen peatlands of the western Siberia Lowland and encompassing a sizable gradient of climate, permafrost, vegetation, soils and Quaternary deposits, to assess a snap-shot (8–23 July 2016) concentration of all major and trace elements in the main stem (~3000 km transect from the Tom River confluence in the south to Salekhard in the north) and its 11 tributaries. During the studied period, corresponding to the end of the spring flood-summer baseflow, there was a systematic decrease, from the south to the north, of Dissolved Inorganic Carbon (DIC), Specific Conductivity, Ca and some labile trace elements (Mo, W and U). In contrast, Dissolved Organic Carbon (DOC), Fe, P, divalent metals (Mn, Ni, Cu, Co and Pb) and low mobile trace elements (Y, Nb, REEs, Ti, Zr, Hf and Th) sizably increased their concentration northward. The observed latitudinal pattern in element concentrations can be explained by progressive disconnection of groundwaters from the main river and its tributaries due to a northward increase in the permafrost coverage. A northward increase in bog versus forest coverage and an increase in DOC and Fe export enhanced the mobilization of insoluble, low mobile elements which were present in organo-ferric colloids (1 kDa—0.45 µm), as confirmed by an in-situ dialysis size fractionation procedure. The chemical composition of the sampled mainstream and tributaries demonstrated significant (p < 0.01) control of latitude of the sampling point; permafrost coverage; proportion of bogs, lakes and floodplain coverage and lacustrine and fluvio-glacial Quaternary deposits of the watershed. This impact was mostly pronounced on DOC, Fe, P, divalent metals (Mn, Co, Ni, Cu and Pb), Rb and low mobile lithogenic trace elements (Al, Ti, Cr, Y, Zr, Nb, REEs, Hf and Th). The pH and concentrations of soluble, highly mobile elements (DIC, SO4, Ca, Sr, Ba, Mo, Sb, W and U) positively correlated with the proportion of forest, loesses, eluvial, eolian, and fluvial Quaternary deposits on the watershed. Consistent with these correlations, a Principal Component Analysis demonstrated two main factors explaining the variability of major and trace element concentration in the Ob River main stem and tributaries. The DOC, Fe, divalent metals and trivalent and tetravalent trace elements were presumably controlled by a northward increase in permafrost, floodplain, bogs, lakes and lacustrine deposits on the watersheds. The DIC and labile alkaline-earth metals, oxyanions (Mo, Sb and W) and U were impacted by southward-dominating forest coverage, loesses and eluvial and fertile soils. Assuming that climate warming in the WSL will lead to a northward shift of the forest and permafrost boundaries, a “substituting space for time” approach predicts a future increase in the concentration of DIC and labile major and trace elements and a decrease of the transport of DOC and low soluble trace metals in the form of colloids in the main stem of the Ob River. Overall, seasonally-resolved transect studies of large riverine systems of western Siberia are needed to assess the hydrochemical response of this environmentally-important territory to on-going climate change.


Forests ◽  
2021 ◽  
Vol 12 (11) ◽  
pp. 1551
Author(s):  
Jiaqi Zhang ◽  
Xiangjin Shen ◽  
Yanji Wang ◽  
Ming Jiang ◽  
Xianguo Lu

The area and vegetation coverage of forests in Changbai Mountain of China have changed significantly during the past decades. Understanding the effects of forests and forest coverage change on regional climate is important for predicting climate change in Changbai Mountain. Based on the satellite-derived land surface temperature (LST), albedo, evapotranspiration, leaf area index, and land-use data, this study analyzed the influences of forests and forest coverage changes on summer LST in Changbai Mountain. Results showed that the area and vegetation coverage of forests increased in Changbai Mountain from 2003 to 2017. Compared with open land, forests could decrease the summer daytime LST (LSTD) and nighttime LST (LSTN) by 1.10 °C and 0.07 °C, respectively. The increase in forest coverage could decrease the summer LSTD and LSTN by 0.66 °C and 0.04 °C, respectively. The forests and increasing forest coverage had cooling effects on summer temperature, mainly by decreasing daytime temperature in Changbai Mountain. The daytime cooling effect is mainly related to the increased latent heat flux caused by increasing evapotranspiration. Our results suggest that the effects of forest coverage change on climate should be considered in climate models for accurately simulating regional climate change in Changbai Mountain of China.


2021 ◽  
Author(s):  
Zongxuan Liu ◽  
Wei Xia ◽  
Bo Sun ◽  
Changlu Guo ◽  
Zhizhou Zhang

Abstract Human language diversity, as a biological phenotype, shall be genetically linked with language gene polymorphism. Meanwhile, this phenotype is historically shaped by local geographical/social factors. But how many language gene polymorphisms have direct correlations with some geography/society characteristics during the long-run evolution of human languages is an interesting question and largely remains uninvestigated. This study selected a series of geography/society factors (including 13 geographical factors and 21 social factors) from 26 countries and 111 single nucleotide polymorphisms (SNPs) randomly selected from 13 language genes. Principal component analysis (PCA) was performed to explore their potential correlations. Preliminary but interesting results were obtained as follow. (1) Most geographical parameters are concentrated into one cluster in the PCA diagram. The cluster contains 12 parameters that are positively correlated with each other; (2) PCA diagrams divide social parameters into four clusters, among which exist positive and negative correlations; (3) The strongest positive correlations were observed at one of ATP2C2 gene SNPs (ATP-1: rs78371901); the strongest negative correlations were found at one of NFXL1 gene SNPs (NFX-6: rs1440228); and the least correlations with language gene SNPs were observed at four geography/society factors: aash (Annual average rainfall), fore (Forest coverage), pden (Population density of the country) and rway (Runway traffic mode).


Author(s):  
Yerko Castillo ◽  
Carlos Oyarzun

Water supply is one of the largest and most valued ecosystem services from forests. This paper presents a systematization of scientific studies about the effects generated by exotic fast-growing forest plantations of Pinus radiata D. Don and of Eucalyptus spp. on water yield in south-central Chilean watersheds (33 - 41ºS), at different spatial and temporal scales. We compiled scientific studies that have at least one year of observations on small and large catchments and experimental plots. Studies in experimental plots of Pinus radiata plantations show that annual evapotranspiration increase from south (40° S) to north (33° S), while in this northernmost site almost the entire incoming precipitation was evapotranspired, and the percolated water was negligible. Studies of water balance in small catchments document a negative linear relationship between total streamflow and forest plantations coverage. Catchments with forest coverage of Pinus or Eucalyptus spp. store less water than catchments with mixed species, mainly due to high interception loss, more net evapotranspiration and reduced percolation. Forest management can alter the accumulation of water in the catchment (soil and groundwater) and forest cover is the fundamental factor in the dynamics water accumulation. Long-term studies focused on changes in forest coverage from native forest to forest plantations in large catchments located in the Mediterranean area (33 - 38º S) of Chile show a sustained reduction in water yield, especially during summertime.


Animals ◽  
2021 ◽  
Vol 11 (9) ◽  
pp. 2692
Author(s):  
Hannes Bergmann ◽  
Katja Schulz ◽  
Franz J. Conraths ◽  
Carola Sauter-Louis

A detailed understanding of environmental risk factors for African swine fever (ASF) in wild boar will be not only essential for risk assessments but also for timely and spatially informed allocation of resources in order to manage wild boar-targeted ASF control measures efficiently. Here, we review currently known environmental risk factors that can influence the occurrence of ASF virus infection in wild boar when compared to disease occurrence in wild boar of a non-exposed reference scenario. Accordingly, the exposure of wild boar to environmental risk factors related to (1) climate, (2) land cover, (3) human activity, (4) wild boar and (5) ASF were evaluated. As key environmental risk factors in this review, increased ASF occurrence in wild boar was associated with seasonal patterns, forest coverage, presence of water, human presence, farming activities, wild boar density and ASF nearness. The review highlights inconsistencies in some of these risk factor associations with disease detection in space and time and may provide valuable insights for the investigation of ASF transmission dynamics. The examined risk information was applied to consider potential improvements of the ASF control strategy in wild boar regarding disease surveillance, hunting, wild boar carcass searches and ASF barrier implementation.


2021 ◽  
Author(s):  
José L. J. Ledesma ◽  
Anna Lupon ◽  
Eugènia Martí ◽  
Susana Bernal

Abstract. In forest headwater streams, metabolic processes are predominately heterotrophic and depend on both the availability of carbon (C) and nitrogen (N) and a favourable C:N stoichiometry. In this context, hydrological conditions and the presence of riparian forests adjacent to streams can play an important, yet understudied role determining dissolved organic carbon (DOC) and nitrate (NO3−) concentrations and DOC:NO3− molar ratios. Here, we aimed to investigate how the interplay between hydrological conditions and riparian forest coverage drives DOC and NO3− supply and DOC:NO3− stoichiometry in an oligotrophic headwater Mediterranean stream. We analysed DOC and NO3− concentrations, and DOC:NO3− molar ratios during both base flow and storm flow conditions at three stream locations along a longitudinal gradient of increased riparian forest coverage. Further, we performed an event analysis to examine the hydroclimatic conditions that favour the transfer of DOC and NO3− from riparian soils to the stream during large storms. Stream DOC and NO3− concentrations were generally low (overall average ± SD was 1.0 ± 0.6 mg C L−1 and 0.20 ± 0.09 mg N L−1), although significantly higher during storm flow compared to base flow conditions in all three stream sites. Optimal DOC:NO3− stoichiometry for stream heterotrophic microorganisms (corresponding to DOC:NO3− molar ratios between 4.8 and 11.7) was prevalent at the midstream and downstream sites under both flow conditions, whereas C-limited conditions were prevalent at the upstream site, which had no surrounding riparian forest. The hydroclimatic analysis of large storm events highlighted different patterns of DOC and NO3− mobilization depending on antecedent soil moisture conditions: drier antecedent conditions promoted rapid elevations of riparian groundwater tables, hydrologically activating a wider and shallower soil layer, and leading to relatively higher increases in stream DOC and NO3− concentrations compared to events preceded by wet conditions. These results suggest that (i) increased supply of limited resources during storms can promote in-stream heterotrophic activity during high flows, especially during large storm events preceded by dry conditions, and (ii) C-limited conditions upstream were gradually overcome downstream, likely due to higher C inputs from riparian forests present at lower elevations. The contrasting spatiotemporal patterns in DOC and NO3− availability and DOC:NO3− stoichiometry observed at the study stream suggests that groundwater inputs from riparian forests are essential for maintaining in-stream heterotrophic activity in oligotrophic, forest headwater catchments.


2021 ◽  
Vol 13 (16) ◽  
pp. 8857
Author(s):  
Longhao Wang ◽  
Jiaxin Jin

Satellite-based land cover products play a crucial role in sustainability. There are several types of land cover products, such as qualitative products with discrete classes, semiquantitative products with several classes at a predetermined ratio, and quantitative products with land cover fractions. The proportions of land cover types in the grids with coarse resolution should be considered when used at the regional scale (e.g., modeling and remote sensing inversion). However, uncertainty, which varies with spatial distribution and resolution, needs to be studied further. This study used MCD12, ESA CCI, and MEaSURES VCF land cover data as indicators of qualitative, semiquantitative, and quantitative products, respectively, to explore the uncertainty of multisource land cover data. The methods of maximum area aggregation, deviation analysis, and least squares regression were used to investigate spatiotemporal changes in forests and nontree vegetation at diverse pixel resolutions across China. The results showed that the average difference in forest coverage for the three products was 8%, and the average deviation was 11.2%. For forest cover, the VCF and ESA CCI exhibited high consistency. For nontree vegetation, the ESA CCI and MODIS exhibited the lowest differences. The overall uncertainty in the temporal and spatial changes of the three products was relatively small, but there were significant differences in local areas (e.g., southeastern hills). Notably, as the spatial resolution decreased, the three products’ uncertainty decreased, and the resolution of 0.1° was the inflection point of consistency.


This study was conducted at Ukhiya Upazila of Cox’s Bazar district to find out the socio-environmental impacts due to Rohingya refugee's invasion of the study area. Both the quantitative and qualitative tools were used to analyzed data and information, in order to assess these impacts. According to the finding, 3918 acre natural and 1879 acre man-made forest coverage was damaged due to Rohingya refugees sheltering in the study area. This study finds out that 42% of the refugees living in the Kutupalong sheltering area are directly dependent on the forest for cooking wood of 1411 tons/day. Moreover, Rohingya`s are significantly affecting other natural resources including soil, agricultural land, and surface and ground-water of the study area. In fact, they using 18.26 million liters of water per day and the ground-water level has been depleted by 25 meters during the time period of 25 August 2017 to February 2018. Furthermore, ~9000 hectares of farming land with local crops (Boro, Aman, Betel leaf) and fruits had been permanently damaged as impacts of Rohingya migration on the area studied. We measured the noise level surroundings of the Rohingya camps, which was 1.5 times higher than the DoE recommended value for the residential area. Various life-threatening diseases were also identified towards the refugees among them diphtheria was most alarming. Moreover, Rohingya are also involved in various antisocial activities including smuggling, drug trafficking, robbery, snatch, theft, etc. Such societal degradation might trigger multiplicative impacts on the environment and overall socio-economic circumstances of the whole Teknaf area.


2021 ◽  
Vol 9 (7) ◽  
pp. 1516
Author(s):  
Maria Razzauti ◽  
Guillaume Castel ◽  
Jean-François Cosson

In nature, host specificity has a strong impact on the parasite’s distribution, prevalence, and genetic diversity. The host’s population dynamics is expected to shape the distribution of host-specific parasites. In turn, the parasite’s genetic structure is predicted to mirror that of the host. Here, we study the tandem Puumala orthohantavirus (PUUV)–bank vole system. The genetic diversity of 310 bank voles and 33 PUUV isolates from 10 characterized localities of Northeast France was assessed. Our findings show that the genetic diversity of both PUUV and voles, was positively correlated with forest coverage and contiguity of habitats. While the genetic diversity of voles was weakly structured in space, that of PUUV was found to be strongly structured, suggesting that the dispersion of voles was not sufficient to ensure a broad PUUV dissemination. Genetic diversity of PUUV was mainly shaped by purifying selection. Genetic drift and extinction events were better reflected than local adaptation of PUUV. These contrasting patterns of microevolution have important consequences for the understanding of PUUV distribution and epidemiology.


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