Drought: A Common Environmental Disaster

Droughts have been identified as an environmental hazard by environmentalists, ecologists, hydrologists, meteorologists, geologists, and agricultural experts. Droughts are characterised by a decrease in precipitation over a lengthy period, such as a season or a year, and can occur in virtually all climatic zones, including both high and low rainfall locations. This study reviewed drought-related impacts on the environment and other components particularly, in South Africa. Several attempts have been made using innovative technology such as earth observation and climate information as recorded in studies. Findings show that the country is naturally water deficient, which adds to the climate fluctuation with the average annual rainfall in South Africa being far below the global average of 860 mm per year. Drought in South Africa’s Western Cape Province, for example, has resulted in employment losses in the province’s agriculture sector. According to the third quarterly labor force survey from 2017, the agricultural industry lost almost 25,000 jobs across the country. In the Western Cape province, about 20,000 of these were lost which has a direct impact on income generation. Many of these impacts were linked to drought events.

Phylogeography of Myrica nana: the Wumeng Mountains as a natural geographical isolation boundary on the Yunnan-Guizhou Plateau

The Yunnan-Guizhou Plateau (YGP) is characterized by the distinctive isolated habitat of limestone Karst Islands and features the Wumeng Mountains (Mts), which divide the YGP into the two Plateaus of Yunnan and Guizhou. This study aims to assess the effects of past geographic and environmental isolation and climate fluctuation on the flora distribution in the YGP. To this effect, we analyzed the phylogeographical pattern and genetic structure for Myrica nana, a vulnerable species endemic to the YGP, based on chloroplast and nuclear ribosomal DNA sequence. The results suggest that the genetic and haplotype network structures are divided into at least two groups—cpDNA haplotype H2 (or nrDNA haplotypes h1, h2, and the native haplotype) mainly distributed to the east of the Wumeng Mts, and cpDNA haplotype H1 and haplotypes H3–H10 (or nrDNA haplotype h3) distributed to the west of the Wumeng Mts. A deep genetic split was noted within the two groups to reach 25 steps, especially for the cpDNA fragment variation. The east–west divergence reveals the existence of a natural geographical isolation boundary in the form of the Wumeng Mts, which divides the YGP into the Yunnan and Guizhou Plateaus. Therefore, there existed at least two glacial refugia during the Quaternary glacial period, along with a genetic diversity center, and at least two large geographic protection units for the vulnerable species of M. nana, distributed throughout the eastern and western sides of the Wumeng Mts. This study not only clarifies that the phylogeographical pattern and genetic structure for M. nana can be attributed to geographic and environmental isolation and climate fluctuation, but it also proposes an effective strategy to protect vulnerable species and the important wild flora of the YGP.

Spatiotemporal Response of Vegetation to Rainfall and Air Temperature Fluctuations in the Sahel: Case Study in the Forest Reserve of Fina, Mali

Forests constitute a key component of the Earth system but the sustainability of the forest reserves in the semi-arid zone is a real concern since its vegetation is very sensitive to the climate fluctuation. The understanding of the mechanisms for the vegetation–climate interaction is poorly studied in the context of African Sahel. In this study, the characteristics of the vegetation response to the fluctuations of precipitation and temperature is determined for the forest reserve of Fina. Rainfall estimates, air temperature and NDVI were re-gridded to a same spatial resolution and standardized with respect to their respective long-term mean. Lag-correlations analysis was used to estimate lag times between changes of climate variables and vegetation response at both seasonal and interannual bases. Results show increasing tendency of NDVI started from the 1990s coinciding the recovery of the rainfall from the 1980s drought, and the obtained correlation (r = 0.66) is statistically significant (p value < 0.01). The strongest responses of vegetation to rainfall and temperature fluctuations were found after 30 and 15 days, respectively. Moreover, at a shorter time lag (e.g., 15 days), more pronounced vegetation responses to both rainfall and temperature were found in agriculturally dominated land while at a longer time lag (e.g., 30 days), a stronger response was observed in Bare-dominated land. The vegetation response to the climate fluctuation is modulated by the land-use/cover dynamics.

Spatiotemporal Response of Vegetation to Rainfall and Temperature fluctuations in the Sahel. Case study in the Forest Reserve of Fina, Mali

Forests constitute a key component of the Earth system but the sustainability of the forest reserves in the semi-arid zone is a real concern since its vegetation is very sensitive to the climate fluctuation. The understanding of the mechanisms for the interaction vegetation-climate is poorly studied in the context of African Sahel. In this study, the characteristics of the vegetation response to the fluctuations of precipitation and temperature is determined for the forest reserve of Fina. Rainfall estimates, air temperature and NDVI are used to establish the lag correlations between fluctuations of vegetation and climate variables at both seasonal and interannual bases. Results shows increasing tendency of NDVI started from the 1990s coinciding the recovery of the rainfall from the 1980s drought and the obtained correlation(r=0.66) is statistically significant (pvalue&lt;0.01). The strongest responses of vegetation to rainfall and temperature fluctuations were found after 30 and 15 days, respectively. Moreover, at shorter time lag (e.g. 15 days) more pronounced vegetation responses to both rainfall and temperature were found in agricultural dominated land while at longer time lag (e.g. 30 days) stronger response was observed in Bare dominated land. The vegetation response to the climate fluctuation is modulated by the land use/cover dynamics. Keywords: NDVI, Rainfall, Air temperature, vegetation response, Fina Forest Reserve, Mali.

The study of multivariance in realization of the plum graft and rootstock combinations adaptivity systems to the changing conditions of environment in the Krasnodar region with the use of digital technologies

The study of rootstocks group, providing the average vigor of growth for the grafted fruit plants, discovered their significant influence on the frost hardiness of the “graft-rootstock” system. The adaptivity of the plum varieties in the different graft and rootstock combinations was studied according to the “frost hardiness” criterion in the stages of the winter and spring development of the flower buds. The computer maps of the plum efficient allocation were created on the studied rootstocks, permitting to lay down the plantings with the lesser risks in the terms of climate fluctuation. It was established, that in the south of Russia the climatic conditions to cultivate Stanley variety on PK SK 1 rootstock, as compared with the rootstock of cherry plum seedling, mostly often used in industrial plantings of plum are mostly favorable. The conducted research contributes to isolation and allocation of the most adaptive graft and rootstock combinations based on their frost hardiness and, consequently, regularity of fruit-bearing and yielding capacity.

Water management and wheat yields in ancient China: Carbon isotope discrimination of archaeological wheat grains

The evaluation of ancient crop production and its response to climate change is key to exploring the ancient demographic and social changes. Wheat is currently the third most widely cultivated crop worldwide and was a major component across of the agricultural systems of the ancient Eurasia. In this study, the Δ13C values of 116 charred wheat grains from 28 archaeological sites, with direct AMS 14C dating of 3952 ± 66 to 389 ± 73 cal yr BP, across northern China are reported. The result shows that the Δ13C values estimated wheat yields ranged from 0.5 to 2.5 Mg ha−1, during the past 4000 years. The water supply and grain yield of wheat cultivation is the highest in China during the Bronze Age; however, the water supply and yield were significantly affected by climate fluctuation in the middle-late Holocene. No significant long-term trend of increasing wheat yield is observed over this interval, but a correlation between Δ13C values estimated wheat yield and cyclical climate changes can be noted.