anthropogenic influences
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2021 ◽  
Vol 66 (3) ◽  
pp. 105-122
Author(s):  
Maria Zachwatowicz

The transformations of cultural landscapes are related to and result from environmental conditions and human impacts. The article describes the main directions of land cover changes in the vicinity of Pińczów in the years 1839–2000. The identified land use patterns were shown and discussed against the background of natural landscape characteristics, and anthropogenic influences associated with socio-political and economic situation of the region in the analyzed period.


2021 ◽  
Vol 194 (1) ◽  
Author(s):  
Paulo T. F. Albuquerque ◽  
Thierry Fredou ◽  
Roberto L. Barcellos ◽  
Julyanne T. B. Melo ◽  
Gilberto N. Arruda ◽  
...  

Author(s):  
Yu Zhang ◽  
Zengchao Hao ◽  
Xuan Zhang ◽  
Fanghua Hao

Abstract Remarkable increases in compound dry and hot events (CDHEs) have been observed in different regions in recent decades. However, the anthropogenic influence on the long-term changes in CDHEs at the global scale has been largely unquantified. In this study, we provide evidence that anthropogenic forcings have contributed to the increased CDHEs over global land areas. We compare the spatial and temporal changes in CDHEs based on climate model simulations from Coupled Model Intercomparison Project Phase 6 (CMIP6) and observations from different datasets. Results show observed occurrences of CDHEs have increased over most regions across global land areas during 1956–2010 relative to 1901–1955. In addition, we find a temporal increase in observed occurrences of CDHEs averaged over global land areas and different continents (except Antarctica) for the period 1901–2010 (with a larger increase during 1951–2010). The spatial and temporal changes in historical all-forcing simulations (with both anthropogenic and natural components) are overall consistent with observations, while those in historical natural-forcing simulations diverge substantially from observations, heightening the key role of anthropogenic forcings in increased CDHEs. Furthermore, we use the probability ratio (PR) to quantify the contribution of anthropogenic forcings to the likelihood of CDHEs since the mid-20th century (1951–2010). We find anthropogenic influences have increased the risk of CDHEs in large regions across the globe except for parts of Eurasia and North America. Overall, our study highlights the important role of anthropogenic influences in increased CDHEs from a global perspective. The mitigation of climate change is thus paramount to reduce the risk of compound dry and hot events.


2021 ◽  
Vol 40 (4) ◽  
pp. 357-363
Author(s):  
Tashkhanim Rakhimova ◽  
Nodira Rakhimova ◽  
Vasila Sharipova ◽  
Natalya Beshko ◽  
Hayitov Rizamat

Abstract The problem of preserving the biological diversity of the Earth is attracting increasing attention of the world scientific community. Rare plant species, as the most vulnerable part of the flora, are under the greatest threat of extinction. In the study of this group of plants, population methods are increasingly being used. Revealing the number, structure, efficiency of self-renewal and resistance of populations of rare plants in relation to anthropogenic influences creates the basis for developing effective measures for their protection. The aim of the study was to assess the current state of coenopopulations of some rare endemic species – Acantholimon nuratavicum Zakirov ex Lincz. (Plumbaginaceae), Cousinia pseudolanata Popov ex Tscherneva (Asteraceae), Lepidolopha nuratavica Krasch. (Asteraceae) included in the Red Book of Uzbekistan. The results showed that in the ecological–coenotic conditions of the Navoi region, the studied coenopopulations are normal and incomplete. Ontogenetic spectra of coenopopulations are centred and left sided, with a peak for middle-aged and young generative individuals, which is associated with the ecological conditions of habitation and anthropogenic pressure.


2021 ◽  
Author(s):  
Lisa Kaser ◽  
Arianna Peron ◽  
Martin Graus ◽  
Marcus Striednig ◽  
Georg Wohlfahrt ◽  
...  

Abstract. Terpenoid emissions above urban areas are a complex mix of biogenic and anthropogenic emission sources. In line with previous studies we found that summertime terpenoid emissions in an alpine city were dominated by biogenic sources, but especially at lower temperatures the anthropogenic influences were non-negligible. Inter-seasonal emission measurements revealed consistency for monoterpenes and sesquiterpenes, but a large difference in isoprene between the summers 2015 and 2018. Standardized emission potentials for monoterpenes and sesquiterpenes were 0.12 nmol m-2 s-1 and 3.0·10-3 nmol m-2 s-1 in 2015 and 0.11 nmol m-2 s-1 and 3.4·10-3 nmol m-2 s-1 in 2018, respectively. Observed isoprene emissions were about four times higher in 2018 than in 2015. This factor decreased to 2.3 after standardizing isoprene emissions to 30 °C air temperature and photosynthetic active radiation (PAR) of 1000 μmol m-2 s-1. Based on emission model parameterizations, increased leaf temperatures can explained ~50 % of these differences, but standard emission potentials remained higher in 2018, when a heat wave persisted. Potential other reasons for the differences such as emission parameterization, footprint changes, water stress conditions and tree trimming are investigated.


Climate ◽  
2021 ◽  
Vol 9 (11) ◽  
pp. 163
Author(s):  
Frank Stefani

The paper aims to quantify solar and anthropogenic influences on climate change, and to make some tentative predictions for the next hundred years. By means of double regression, we evaluate linear combinations of the logarithm of the carbon dioxide concentration and the geomagnetic aa index as a proxy for solar activity. Thereby, we reproduce the sea surface temperature (HadSST) since the middle of the 19th century with an adjusted R2 value of around 87 percent for a climate sensitivity (of TCR type) in the range of 0.6 K until 1.6 K per doubling of CO2. The solution of the double regression is quite sensitive: when including data from the last decade, the simultaneous occurrence of a strong El Niño and of low aa values leads to a preponderance of solutions with relatively high climate sensitivities around 1.6 K. If these later data are excluded, the regression delivers a significantly higher weight of the aa index and, correspondingly, a lower climate sensitivity going down to 0.6 K. The plausibility of such low values is discussed in view of recent experimental and satellite-borne measurements. We argue that a further decade of data collection will be needed to allow for a reliable distinction between low and high sensitivity values. In the second part, which builds on recent ideas about a quasi-deterministic planetary synchronization of the solar dynamo, we make a first attempt to predict the aa index and the resulting temperature anomaly for various typical CO2 scenarios. Even for the highest climate sensitivities, and an unabated linear CO2 increase, we predict only a mild additional temperature rise of around 1 K until the end of the century, while for the lower values an imminent temperature drop in the near future, followed by a rather flat temperature curve, is prognosticated.


2021 ◽  
Vol 8 (11) ◽  
Author(s):  
A. J. Marais ◽  
K. Lloyd ◽  
H. A. Smit-Robinson ◽  
L. R. Brown

The white-winged flufftail is listed as critically endangered, and limited knowledge about the species' ecology has been identified as a limiting factor to effectively conserving the bird. Little is known about the vegetation inhabited by the white-winged flufftail, which hampers the identification and management of its habitat. This study presents a fine-scale classification and description of the vegetation of wetland sites where the bird is known to be present. A plant phytosociological study was conducted to describe the plant communities and vegetation structure of the habitat. Three sites were selected at Verloren Valei Nature Reserve and two at Middelpunt Wetland, Mpumalanga, South Africa, shortly after the white-winged flufftail breeding season. A total of 60 sample plots were placed within the study sites, where all plant species present were recorded and identified. Other aspects such as plant height, water depth and anthropogenic influences were also documented. A modified TWINSPAN analysis resulted in the identification of three sub-communities that can be grouped into one major community. The Cyperaceae, Asteraceae and Poaceae families dominate the vegetation, with the sedges Carex austro-africana and Cyperus denudatus being dominant, and the grasses Leersia hexandra and Arundinella nepalensis co-dominant. The broad habitat structure consisted of medium to tall herbaceous plants (0.5–0.7 m) with shallow slow-flowing water.


Author(s):  
Ju Hyeon Lee ◽  
Sae Yun Kwon ◽  
Runsheng Yin ◽  
Laura M. Motta ◽  
Aaron Y. Kurz ◽  
...  

2021 ◽  
Vol 786 ◽  
pp. 147574
Author(s):  
Meichen Jiang ◽  
Yuexin He ◽  
Conghe Song ◽  
Yuepeng Pan ◽  
Tong Qiu ◽  
...  

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