scholarly journals Differing Responses to Rainfall Suggest More Than One Functional Type of Grassland in South Africa

2018 ◽  
Vol 10 (12) ◽  
pp. 2055 ◽  
Author(s):  
Catherine Van den Hoof ◽  
Michel Verstraete ◽  
Robert Scholes
Keyword(s):  
Climate Change ◽  
South Africa ◽  
Spatial Scales ◽  
Annual Rainfall ◽  
Mean Annual Precipitation ◽  
Spatial And Temporal Variability ◽  
Arid Zones ◽  
Monthly Precipitation ◽  
Good Tool ◽  
Grassland Productivity

Grasslands, which represent around 40% of the terrestrial area, are mostly located in arid and semi-arid zones. Semiarid ecosystems in Africa have been identified as being particularly vulnerable to the impacts of increased human pressure on land, as well as enhanced climate variability. Grasslands are indeed very responsive to variations in precipitation. This study evaluates the sensitivity of the grassland ecosystem to precipitation variability in space and time, by identifying the factors controlling this response, based on monthly precipitation data from Climate Hazards Group InfraRed Precipitation with Station data (CHIRPS) and the Fraction of Absorbed Photosynthetically Active Radiation (FAPAR) data from the Multi-angle Imaging SpectroRadiometer-High Resolution (MISR-HR) datasets, used as proxy for productivity, at 60 grassland sites in South Africa. Our results show that MISR-HR products adequately capture the spatial and temporal variability in productivity at scales that are relevant to this study, and they are therefore a good tool to study climate change impacts on ecosystem at small spatial scales over large spatial and temporal domains. We show that combining several determinants and accounting for legacies improves our ability to understand patterns, identify areas of vulnerability, and predict the future of grassland productivity. Mean annual precipitation is a good predictor of mean grassland productivity. The grasslands with a mean annual rainfall above about 530 mm have a different functional response to those receiving less than that amount of rain, on average. On the more arid and less fertile soils, large inter-annual variability reduces productivity. Our study suggests that grasslands on the more marginal soils are the most vulnerable to climate change.

Influence of historical and contemporary habitat changes on the population genetics of the endemic South African parrot Poicephalus robustus

2019 ◽  
Vol 30 (2) ◽  
pp. 236-259
Author(s):  
WILLEM G. COETZER ◽  
COLLEEN T. DOWNS ◽  
MIKE R. PERRIN ◽  
SANDI WILLOWS-MUNRO
Keyword(s):  
Climate Change ◽  
South Africa ◽  
Spatial Scales ◽  
Population Decline ◽  
Source Population ◽  
Population Bottlenecks ◽  
Eastern Cape ◽  
Forest Patches ◽  
In The Wild ◽  
Fragmented Forests

SummaryThe Cape Parrot Poicephalus robustus is a habitat specialist, restricted to forest patches in the Eastern Cape (EC), KwaZulu-Natal (KZN) and Limpopo provinces of South Africa. Recent census estimates suggest that there are less than 1,600 parrots left in the wild, although historical data suggest that the species was once more numerous. Fragmentation of the forest biome is strongly linked to climate change and exploitation of the forest by the timber industry. We examine the subpopulation structure and connectivity between fragmented populations across the distribution of the species. Differences in historical and contemporary genetic structure of Cape Parrots is examined by including both modern samples, collected from 1951 to 2014, and historical samples, collected from 1870 to 1946. A total of 114 individuals (historical = 29; contemporary = 85) were genotyped using 16 microsatellite loci. We tested for evidence of partitioning of genotypes at both a temporal and spatial scales by comparing shifts in allelic frequencies of historical (1870–1946) and contemporary (1951–2014) samples across the distribution of the species. Tests for population bottlenecks were also conducted to determine if anthropogenic causes are the main driver of population decline in this species. Analyses identified three geographically correlated genetic clusters. A southern group restricted to forest patches in the EC, a central group including birds from KZN and a genetically distinct northern Limpopo cluster. Results suggest that Cape Parrots have experienced at least two population bottlenecks. An ancient decline during the mid-Holocene (∼ 1,800-3,000 years before present) linked to climate change, and a more recent bottleneck, associated with logging of forests during the early 1900s. This study highlights the effects of climate change and human activities on an endangered species associated with the naturally fragmented forests of eastern South Africa. These results will aid conservation authorities with the planning and implementation of future conservation initiatives. In particular, this study emphasises the Eastern Cape mistbelt forests as an important source population for the species and calls for stronger conservation of forest patches in South Africa to promote connectivity of forest taxa.

The Impact of Climate Change and Variability on Small-Scale Peri-Urban Horticultural Farmers in Domboshawa, Zimbabwe

2019 ◽  
pp. 46-69
Author(s):  
Vincent Itai Tanyanyiwa
Keyword(s):  
Climate Change ◽  
Smallholder Farmers ◽  
Climate Change Impacts ◽  
Annual Rainfall ◽  
Small Scale ◽  
Spatial And Temporal Variability ◽  
Clear Understanding ◽  
Rainfall Events ◽  
Climate Change And Variability ◽  
Dry Spells

Zimbabwe is a semi-arid country reliant on regular rains (November-April). Mean annual rainfall is low, and many rivers in the drier parts of the country are not perennial. In the small-scale horticultural sector, irrigation becomes handy. Rainfall exhibits spatial and temporal variability. This scenario is characterized by shifts in the onset of rains, increases in frequency and intensity of heavy rainfall events, increases in the proportion of low rainfall years, decreases in low-intensity rainfall events, and increases in the frequency and intensity of mid-season dry spells. Drought have increased in frequency and intensity. Agriculture is the main source of income for most smallholder farmers who depend on rain-fed cropping and livestock rearing. Adaptation of agriculture to climate variability and change impacts is vital for livelihood. To develop appropriate strategies and institutional responses to climate change adaptation, a clear understanding of climate change impacts on smallholder farmers at farm-level is vital.

The Impact of Climate Change and Variability on Small-Scale Peri-Urban Horticultural Farmers in Domboshawa, Zimbabwe

2022 ◽  
pp. 1535-1553
Author(s):  
Vincent Itai Tanyanyiwa
Keyword(s):  
Climate Change ◽  
Smallholder Farmers ◽  
Climate Change Impacts ◽  
Annual Rainfall ◽  
Small Scale ◽  
Spatial And Temporal Variability ◽  
Clear Understanding ◽  
Rainfall Events ◽  
Climate Change And Variability ◽  
Dry Spells

Zimbabwe is a semi-arid country reliant on regular rains (November-April). Mean annual rainfall is low, and many rivers in the drier parts of the country are not perennial. In the small-scale horticultural sector, irrigation becomes handy. Rainfall exhibits spatial and temporal variability. This scenario is characterized by shifts in the onset of rains, increases in frequency and intensity of heavy rainfall events, increases in the proportion of low rainfall years, decreases in low-intensity rainfall events, and increases in the frequency and intensity of mid-season dry spells. Drought have increased in frequency and intensity. Agriculture is the main source of income for most smallholder farmers who depend on rain-fed cropping and livestock rearing. Adaptation of agriculture to climate variability and change impacts is vital for livelihood. To develop appropriate strategies and institutional responses to climate change adaptation, a clear understanding of climate change impacts on smallholder farmers at farm-level is vital.

scholarly journals Assessment of Local Climate Change: Historical Trends and RCM Multi-Model Projections Over the Salento Area (Italy)

Water ◽  
2018 ◽  
Vol 10 (8) ◽  
pp. 978 ◽  
Author(s):  
Marco D’Oria ◽  
Maria Tanda ◽  
Valeria Todaro
Keyword(s):  
Climate Change ◽  
Climate Models ◽  
Climate Model ◽  
Heat Waves ◽  
Regional Climate ◽  
Warm Season ◽  
Annual Rainfall ◽  
Maximum Temperature ◽  
Monthly Precipitation ◽  
Local Climate

This study provides an up-to-date analysis of climate change over the Salento area (southeast Italy) using both historical data and multi-model projections of Regional Climate Models (RCMs). The accumulated anomalies of monthly precipitation and temperature records were analyzed and the trends in the climate variables were identified and quantified for two historical periods. The precipitation trends are in almost all cases not significant while the temperature shows statistically significant increasing tendencies especially in summer. A clear changing point around the 80s and at the end of the 90s was identified by the accumulated anomalies of the minimum and maximum temperature, respectively. The gradual increase of the temperature over the area is confirmed by the climate model projections, at short—(2016–2035), medium—(2046–2065) and long-term (2081–2100), provided by an ensemble of 13 RCMs, under two Representative Concentration Pathways (RCP4.5 and RCP8.5). All the models agree that the mean temperature will rise over this century, with the highest increases in the warm season. The total annual rainfall is not expected to significantly vary in the future although systematic changes are present in some months: a decrease in April and July and an increase in November. The daily temperature projections of the RCMs were used to identify potential variations in the characteristics of the heat waves; an increase of their frequency is expected over this century.

scholarly journals Streamflow into Beijing and Its Response to Climate Change and Human Activities over the Period 1956–2016

Water ◽  
2020 ◽  
Vol 12 (3) ◽  
pp. 622 ◽  
Author(s):  
Xing Mu ◽  
Hao Wang ◽  
Yong Zhao ◽  
Huan Liu ◽  
Guohua He ◽  
...  
Keyword(s):  
Climate Change ◽  
Human Activities ◽  
Potential Evapotranspiration ◽  
Spatial Scales ◽  
Meteorological Data ◽  
Kendall Test ◽  
Spatial And Temporal Variability ◽  
Annual Streamflow ◽  
Significant Downward Trend ◽  
Human Effects

Streamflow is likely affected by climate change and human activities. In this study, hydro-meteorological data from six rivers upstream of Beijing, namely, the Yongdinghe, Baihe, Heihe, Chaohe, Juhe, and Jumahe Rivers, were analyzed to quantify the spatial and temporal variability of streamflow and their responses to climate change and human activities over the period of 1956–2016. The Mann–Kendall test and moving t-test were used to detect trends and changing points of the annual streamflow. Results showed that the streamflow into Beijing experienced a statistically significant downward trend (p < 0.05), abruptly changing after the early 1980s, owing to climate and human effects. The climate elasticities of the streamflow showed that a 10% decrease in precipitation would result in a 24.5% decrease in total streamflow, whereas a 10% decrease in potential evapotranspiration would induce a 37.7% increase in total streamflow. Human activities accounted for 87% of the reduction in total streamflow, whereas 13% was attributed to climate change. Lastly, recommendations are provided for adaptive management of water resources at different spatial scales.

scholarly journals Rainfall and river flow trends for the Western Cape Province, South Africa

2019 ◽  
Vol 115 (9/10) ◽  
Author(s):  
Rakhee Lakhraj-Govender ◽  
Stefan W. Grab
Keyword(s):  
Climate Change ◽  
South Africa ◽  
River Flow ◽  
Supply And Demand ◽  
Temporal Distribution ◽  
Annual Rainfall ◽  
Western Cape ◽  
Western Cape Province ◽  
Winter Rainfall ◽  
Intergovernmental Panel

Climate change has the potential to alter the spatio-temporal distribution of rainfall, subsequently affecting the supply and demand of water resources. In a water-stressed country such as South Africa, this effect has significant consequences. To this end, we investigated annual and winter rainfall and river flow trends for the Western Cape Province over two periods: 1987–2017 and 1960–2017. Annual rainfall for the most recent 30-year period shows decreasing trends, with the largest magnitude of decrease at the SA Astronomical Observatory rainfall station (-54.38 mm/decade). With the exception of the significant decreasing winter rainfall trend at Langewens (-34.88 mm/decade), the trends vary between stations for the period 1960–2017. For the period 1987–2017, statistically significant decreasing winter trends were found at four of the seven stations, and range from -6.8 mm/decade at Cape Columbine to -34.88 mm/decade at Langewens. Similarly, the magnitudes of decreasing winter river flow at Bree@Ceres and Berg@Franschoek are greater for the more recent 30-year period than for 1960–2017. Correlation coefficients for Vilij@Voeliv rainfall and four river flow stations Berg@Franschoek, Bree@Ceres, Wit River@Drosterkloof and Little Berg@Nieuwkloof) are stronger for shorter periods (i.e. 1987–2017 and 2007–2017) than that for the longer period, 1960–2017. The Intergovernmental Panel on Climate Change emphasises the importance of studies to assist with model prediction uncertainties. To this end, our study expands the understanding of regional hydrological responses to rainfall change in the water stressed region of the Western Cape Province.

scholarly journals Assessment of smallholder farmers’ perception and adaptation response to climate change in the Olifants catchment, South Africa

2021 ◽  
Author(s):  
Mary Funke Olabanji ◽  
Nerhene Davis ◽  
Thando Ndarana ◽  
Anesu Gelfand Kuhudzai ◽  
Dawn Mahlobo
Keyword(s):  
Climate Change ◽  
South Africa ◽  
Smallholder Farmers ◽  
Meteorological Data ◽  
Group Discussion ◽  
Kendall Test ◽  
Adaptation Strategies ◽  
Annual Rainfall ◽  
Climate Data ◽  
Climate Trend

Abstract Climate change is expected to affect the livelihood of rural farmers in South Africa particularly the smallholder farmers, due to their overwhelming dependence on rain-fed agriculture. This study examines smallholder farmers' perception of climate change, the adaptation strategies adopted and factors that influences their adaptive decisions. The unit of data collection was household interview and focus group discussion. Climate data for the Olifants catchment (1986–2015) were also collected to validate farmers' perception of climate change with actual climate trend. Data collected were analysed using descriptive statistics, Mann–Kendall trend, Sen's slope estimator and multinomial logit regression model. Results revealed that smallholder farmers are aware of climate change (98%), their perception of these changes aligns with actual meteorological data, as the Mann–Kendall test confirms a decreasing inter-annual rainfall trend (−0.172) and an increasing temperature trend (0.004). These changes in temperature and precipitation have prompted the adoption of various adaptation responses, among which the use of improved seeds, application of chemical fertilizer and changing planting dates were the most commonly practised. The main barriers to the adoption of adaptation strategies were lack of access to credit facility, market, irrigation, information about climate change and lack of extension service. The implication of this study is to provide information to policy-makers on the current adaptation responses adopted by farmers and ways in which their adaptive capacity can be improved in order to ensure food security.

scholarly journals Spatial and Temporal Variability in Rainfall Erosivity Under Alpine Climate: A Slovenian Case Study Using Optical Disdrometer Data

2021 ◽  
Vol 9 ◽  
Author(s):  
Nejc Bezak ◽  
Sašo Petan ◽  
Matjaž Mikoš
Keyword(s):  
Temporal Variability ◽  
Large Scale ◽  
Annual Rainfall ◽  
Mean Annual Precipitation ◽  
Rainfall Erosivity ◽  
Spatial And Temporal Variability ◽  
Strongly Correlated ◽  
Erosion Rates ◽  
Precipitation Events

Rainfall erosivity is one of the most important parameters that influence soil erosion rates. It is characterized by a large spatial and temporal variability. For example, in Slovenia, which covers around 20,000 km2, the annual rainfall erosivity ranges from less than 1,000 MJ mm ha−1 h−1 to more than 10,000 MJ mm ha−1 h−1. Drop size distribution (DSD) data are needed to investigate rainfall erosivity characteristics. More than 2 years of DSD measurements using optical disdrometers located at six stations in Slovenia were used to investigate the spatial and temporal variability in rainfall erosivity in Slovenia. Experimental results have indicated that elevation is a poor predictor of rainfall erosivity and that erosivity is more strongly correlated to the mean annual precipitation. Approximately 90% of the total kinetic energy (KE) was accounted for in about 35% of 1 min disdrometer data. The highest 1 min intensities (I) and consequently also KE values were measured in summer followed by autumn and spring. The local KE-I equation yielded an acceptable fit to the measured data in case of all six stations. The relatively large percentage of 1 min rainfall intensities above 5 mm/h can at least partially explain some very high annual rainfall erosivity values (i.e., near or above 10,000 MJ mm ha−1 h−1). Convective and large-scale precipitation events also result in various rainfall erosivity characteristics. The station microlocation and wind impacts in case of some stations yielded relatively large differences between the data measured using the optical disdrometer and the pluviograph. Preliminary conclusions have been gathered, but further measurements are needed to get even better insight into spatial and temporal variability in rainfall erosivity under Alpine climate in Slovenia.

scholarly journals Multi-Criteria Decision Framework to Evaluate Bias Corrected Climate Change Projections in the Piracicaba River Basin

2021 ◽  
Author(s):  
Camila Billerbeck ◽  
Ligia Monteiro da Silva ◽  
Silvana Susko Marcellini ◽  
Arisvaldo Méllo Junior
Keyword(s):  
Climate Change ◽  
River Basin ◽  
Climate Models ◽  
Regional Climate ◽  
Climate Change Impacts ◽  
Regional Climate Models ◽  
Annual Rainfall ◽  
Monthly Precipitation ◽  
Climate Change Effects ◽  
Piracicaba River

Abstract Regional climate models (RCM) are the main tools for climate change impacts assessment in hydrological studies. These models, however, often show biases when compared to historical observations. Bias Correction (BC) are useful techniques to improve climate projection outputs. This study presents a multi-criteria decision analysis (MCDA) framework to compare combinations of RCM with selected BC methods. The comparison was based on the modified Kling-Gupta efficiency (KGE’). The criteria evaluated the general capability of models in reproducing the observed data main statistics. Other criteria evaluated were the relevant aspects for hydrological studies, such as seasonality, dry and wet periods. We applied four BC methods in four RCM monthly rainfall outputs from 1961 to 2005 in the Piracicaba river basin. The Linear Scaling (LS) method showed higher improvements in the general performance of the models. The RCM Eta-HadGEM2-ES, corrected with Standardized Reconstruction (SdRc) method, achieved the best results when compared to the observed precipitation. The bias corrected projected monthly precipitation (2006-2098) preserved the main signal of climate change effects when compared to the original outputs regarding annual rainfall. However, SdRc produced significant decrease in monthly average rainfall, higher than 45% for July, August and September for RCP4.5 and RCP8.5 scenarios.

scholarly journals Assessment of Seasonal and Annual Rainfall Trends and Variability in Sharjah City, UAE

2016 ◽  
Vol 2016 ◽  
pp. 1-13 ◽  
Author(s):  
Tarek Merabtene ◽  
Mohsin Siddique ◽  
Abdallah Shanableh
Keyword(s):  
Climate Change ◽  
Temporal Variability ◽  
Low Frequency ◽  
Annual Rainfall ◽  
Spatial And Temporal Variability ◽  
Rainfall Trend ◽  
Significant Drop ◽  
Statistical Measures ◽  
Rainfall Trends ◽  
The Impact

Although a few studies on rainfall spatial and temporal variability in the UAE have been carried out, evidence of the impact of climate change on rainfall trends has not been reported. This study aims at assessing the significance of long-term rainfall trends and temporal variability at Sharjah City, UAE. Annual rainfall and seasonal rainfall extending over a period of 81 years (1934–2014) recorded at Sharjah International Airport have been analyzed. To this end, several parametric and nonparametric statistical measures have been applied following systematic data quality assessment. The analyses revealed that the annual rainfall trend decreased from −3 mm to −9.4 mm per decade over the study periods. The decreasing annual rainfall trend is mainly driven by the significant drop in winter rainfall, particularly during the period from 1977 to 2014. The results also indicate that high probability extreme events have shifted toward low frequency (12.7 years) with significant variations in monthly rainfall patterns and periodicity. The findings of the present study suggest reevaluating the derivation of design rainfall for infrastructure of Sharjah City and urge developing an integrated framework for its water resources planning and risk under climate change impacts scenarios.

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