scholarly journals Spatio–Environmental Analysis of Vespula germanica Nest Records Explains Slow Invasion in South Africa

Insects ◽  
2021 ◽  
Vol 12 (8) ◽  
pp. 732
Author(s):  
Ruan Veldtman ◽  
Derek Daly ◽  
Gerard F. H. v. G. Bekker
Keyword(s):  
South Africa ◽  
Hot Spot ◽  
Moisture Stress ◽  
Geographic Area ◽  
Annual Rainfall ◽  
General Distribution ◽  
Maximum Temperature ◽  
Distribution Area ◽  
Moisture Index ◽  
Vespula Germanica

Investigating the distributions of invasive species in marginal habitats can give clues to the factors constraining invasive spread. Vespula germanica is the most widely distributed of all the invasive Vespids, which in the Southern Hemisphere typically have large extensive invasive populations. In contrast, the invasion into South Africa has been slow and is still confined to a small geographic area. Here we analyse the distribution of all recent nest records in South Africa (n = 405). The distance to main rivers, mean annual rainfall, summer normalised difference moisture index (NDMI) values, and mean annual temperatures (average, minimum, maximum, and summer maximum temperature) was measured for every nest. We find that value ranges of these variables are different between the value ranges recorded for nests, the general distribution area of the wasp, and the area of absence. Optimised Hot Spot Analysis was used to quantify spatial structure in the measured climatic variables. Generally, factors related to moisture stress set the environmental limits of V. germanica’s landscape distribution. Due to the strong preference of nesting sites close to river courses, for higher rainfall conditions, medium to medium-high NDMI values, and lower mean annual temperatures, it is unlikely that V. germanica will be able to spread uniformly where it is currently found in South Africa.

scholarly journals Impacts of Rainfall and Temperature Changes on Smallholder Agriculture in the Limpopo Province, South Africa

Water ◽  
2021 ◽  
Vol 13 (20) ◽  
pp. 2872
Author(s):  
Sydney Shikwambana ◽  
Ntokozo Malaza ◽  
Karabo Shale
Keyword(s):  
Climate Change ◽  
South Africa ◽  
Crop Production ◽  
Smallholder Farmers ◽  
Aridity Index ◽  
Scenario Planning ◽  
Limpopo Province ◽  
Annual Rainfall ◽  
Remotely Sensed Data ◽  
Moisture Index

The intensity and frequency in the recurrence of extreme climate events are compounding the vulnerability of smallholder farmers, who have always lacked the resources to adapt. The increasing temperatures and decreasing rainfall are exacerbating water scarcity challenges through drought recurrence. There is an urgent need for pathways that lead towards Sustainable Development Goals, mainly Goals 1 (no poverty) and 2 (zero hunger) in poor rural communities. This study assessed rainfall and temperature trends from 1960 to 2018 and their impacts on crop production in the Mopani and Vhembe Districts of Limpopo Province, South Africa. Trend analysis was used to analyse rainfall patterns, as well as the trends in temperature recorded for the past 58 years. The climate moisture index (CMI) and runoff estimates were used to assess the degree of aridity and water availability, respectively. Geographic Information Systems (GIS) and remotely sensed data were used to assess the changes over time. The total annual rainfall has declined significantly while annual minimum and maximum temperatures have increased significantly during the period under observation. An aridity index of −0.70 calculated for the study areas classifies the districts as dry and water scarce. The results of the analysis also indicate that the districts are climate change hot spots, and are highly vulnerable to the impacts of climate change. The changes are compounding water and food insecurity. Policy and decision-makers should focus on enhancing adaptation and resilience initiatives in the study areas through systematic, transformative, and integrated approaches, such as scenario planning, circular economy, and nexus planning.

The Biology of Mediterranean-Type Ecosystems

2018 ◽  
Author(s):  
Karen J. Esler ◽  
Anna L. Jacobsen ◽  
R. Brandon Pratt
Keyword(s):  
Climate Change ◽  
South Africa ◽  
Invasive Species ◽  
Habitat Loss ◽  
Endemic Species ◽  
Geographic Area ◽  
Cutting Edge ◽  
Wide Range ◽  
The Mediterranean ◽  
Mediterranean Type Ecosystems

The world’s mediterranean-type climate regions (including areas within the Mediterranean, South Africa, Australia, California, and Chile) have long been of interest to biologists by virtue of their extraordinary biodiversity and the appearance of evolutionary convergence between these disparate regions. Comparisons between mediterranean-type climate regions have provided important insights into questions at the cutting edge of ecological, ecophysiological and evolutionary research. These regions, dominated by evergreen shrubland communities, contain many rare and endemic species. Their mild climate makes them appealing places to live and visit and this has resulted in numerous threats to the species and communities that occupy them. Threats include a wide range of factors such as habitat loss due to development and agriculture, disturbance, invasive species, and climate change. As a result, they continue to attract far more attention than their limited geographic area might suggest. This book provides a concise but comprehensive introduction to mediterranean-type ecosystems. As with other books in the Biology of Habitats Series, the emphasis in this book is on the organisms that dominate these regions although their management, conservation, and restoration are also considered.

scholarly journals Spatiotemporal Evolution of Fractional Vegetation Cover and Its Response to Climate Change Based on MODIS Data in the Subtropical Region of China

2021 ◽  
Vol 13 (5) ◽  
pp. 913
Author(s):  
Hua Liu ◽  
Xuejian Li ◽  
Fangjie Mao ◽  
Meng Zhang ◽  
Di’en Zhu ◽  
...  
Keyword(s):  
Vegetation Cover ◽  
Minimum Temperature ◽  
Maximum Temperature ◽  
Distribution Area ◽  
Spatiotemporal Pattern ◽  
Climate Factors ◽  
Important Indicator ◽  
Fractional Vegetation Cover ◽  
Annual Minimum Temperature ◽  
Total Study Area

The subtropical vegetation plays an important role in maintaining the structure and function of global ecosystems, and its contribution to the global carbon balance are receiving increasing attention. The fractional vegetation cover (FVC) as an important indicator for monitoring environment change, is widely used to analyze the spatiotemporal pattern of regional and even global vegetation. China is an important distribution area of subtropical vegetation. Therefore, we first used the dimidiate pixel model to extract the subtropical FVC of China during 2001–2018 based on MODIS land surface reflectance data, and then used the linear regression analysis and the variation coefficient to explore its spatiotemporal variations characteristics. Finally, the partial correlation analysis and the partial derivative model were used to analyze the influences and contributions of climate factors on FVC, respectively. The results showed that (1) the subtropical FVC had obvious spatiotemporal heterogeneity; the FVC high-coverage and medium-coverage zones were concentratedly and their combined area accounted for more than 70% of the total study area. (2) The interannual variation in the average subtropical FVC from 2001 to 2018 showed a significant growth trend. (3) In 76.28% of the study area, the regional FVC showed an increasing trend, and the remaining regional FVC showed a decreasing trend. However, the overall fluctuations in the FVC (increasing or decreasing) in the region were relatively stable. (4) The influences of climate factors to the FVC exhibited obvious spatial differences. More than half of all pixels exhibited the influence of the average annual minimum temperature and the annual precipitation had positive on FVC, while the average annual maximum temperature had negative on FVC. (5) The contributions of climate changes to FVC had obvious heterogeneity, and the average annual minimum temperature was the main contribution factor affecting the dynamic variations of FVC.

scholarly journals Changing boundaries: Overcoming modifiable areal unit problems related to unemployment data in South Africa

2016 ◽  
Vol Volume 112 (Number 3/4) ◽  
Author(s):  
Gina Weir-Smith ◽  
◽  
Keyword(s):  
South Africa ◽  
Rural Areas ◽  
Census Data ◽  
Metropolitan Areas ◽  
Geographic Area ◽  
Areal Unit ◽  
Areal Interpolation ◽  
Unemployment Data ◽  
Municipal Boundaries ◽  
Longitudinal Comparison

Abstract The longitudinal comparison of census data in spatial format is often problematic because of changes in administrative boundaries. Such shifting boundaries are referred to as the modifiable areal unit problem (MAUP). This article utilises unemployment data between 1991 and 2007 in South Africa to illustrate the challenge and proposes ways to overcome it. Various censuses in South Africa use different reporting geographies. Unemployment data for magisterial districts of census 1991 and 1996 were re-modelled to the 2005 municipal boundaries. This article showed that areal interpolation to a common administrative boundary could overcome these reporting obstacles. The results confirmed more accurate interpolations in rural areas with standard errors below 3300. Conversely, the largest errors were recorded in the metropolitan areas. Huge increases in unemployment between 1996 and 2001 statistics were also evident, especially in the metropolitan areas. Although such areas are more complex in nature, making it more difficult to accurately calculate census data, the increase in unemployment could also be the result of census taking methods. The article concludes that socio-economic data should be available at the smallest possible geographic area to ensure more accurate results in interpolation. It also recommends that new output areas be conceptualised to create a seamless database of census data from 1991 to 2011 in South Africa.

scholarly journals Vegetation change (1988–2010) in Camdeboo National Park (South Africa), using fixed-point photo monitoring: The role of herbivory and climate

Koedoe ◽  
2013 ◽  
Vol 55 (1) ◽  
Author(s):  
Mmoto L. Masubelele ◽  
Michael T. Hoffman ◽  
William Bond ◽  
Peter Burdett
Keyword(s):  
South Africa ◽  
Fixed Point ◽  
National Parks ◽  
Vegetation Cover ◽  
National Park ◽  
Vegetation Change ◽  
Growth Form ◽  
Annual Rainfall ◽  
Management Interventions

Fixed-point photo monitoring supplemented by animal census data and climate monitoring potential has never been explored as a long-term monitoring tool for studying vegetation change in the arid and semi-arid national parks of South Africa. The long-term (1988–2010), fixed-point monitoring dataset developed for the Camdeboo National Park, therefore, provides an important opportunity to do this. Using a quantitative estimate of the change in vegetation and growth form cover in 1152 fixed-point photographs, as well as series of step-point vegetation surveys at each photo monitoring site, this study documented the extent of vegetation change in the park in response to key climate drivers, such as rainfall, as well as land use drivers such as herbivory by indigenous ungulates. We demonstrated the varied response of vegetation cover within three main growth forms (grasses, dwarf shrubs [< 1 m] and tall shrubs [> 1 m]) in three different vegetation units and landforms (slopes, plains, rivers) within the Camdeboo National Park since 1988. Sites within Albany Thicket and Dwarf Shrublands showed the least change in vegetation cover, whilst Azonal vegetation and Grassy Dwarf Shrublands were more dynamic. Abiotic factors such as drought and flooding, total annual rainfall and rainfall seasonality appeared to have the greatest influence on growth form cover as assessed from the fixed-point photographs. Herbivory appeared not to have had a noticeable impact on the vegetation of the Camdeboo National Park as far as could be determined from the rather coarse approach used in this analysis and herbivore densities remained relatively low over the study duration.Conservation implications: We provided an historical assessment of the pattern of vegetation and climatic trends that can help evaluate many of South African National Parks’ biodiversity monitoring programmes, especially relating to habitat change. It will help arid parks in assessing the trajectories of vegetation in response to herbivory, climate and management interventions.

scholarly journals A Spatial Analysis of Tuberculosis Related Mortality in South Africa

2021 ◽  
Vol 18 (22) ◽  
pp. 11865
Author(s):  
Dan Kibuuka ◽  
Charles Mpofu ◽  
Penny Neave ◽  
Samuel Manda
Keyword(s):  
Public Health ◽  
South Africa ◽  
Mortality Rate ◽  
Spatial Epidemiology ◽  
Hot Spot ◽  
Mortality Rates ◽  
Cold Spot ◽  
The South ◽  
Female Population ◽  
Death Rates

Background: South Africa, with an estimated annual tuberculosis (TB) incidence of 360,000 cases in 2019, remains one of the countries with the largest burden of TB in the world. The identification of highly burdened TB areas could support public health policy planners to optimally target resources and TB control and prevention interventions. Objective: To investigate the spatial epidemiology and distribution of TB mortality in South Africa in 2010 and its association with area-level poverty and HIV burden. Methods: The study analysed a total of 776,176 TB deaths for the period 2005–2015. Local and global and spatial clustering of TB death rates were investigated by Global and Local Moran’s Indices methods (Moran’s I). The spatial regression analysis was employed to assess the effect of poverty and HIV on TB mortality rates. Results: There was a significant decrease in TB mortality rate, from 179 per 100,000 population in 2005 to 60 per 100,000 population in 2015. The annual TB mortality rate was higher among males (161.5 per 100,000 male population; (95% confidence interval (CI) 132.9, 190.0) than among females (123.2 per 100,000 female population; (95% CI 95.6, 150.8)). The 35–44 age group experienced higher TB mortality rates, regardless of gender and time. Hot spot clusters of TB mortality were found in the South-Eastern parts of the country, whereas cold spot clusters were largely in the north-eastern parts. Tuberculosis death rates were positively associated with poverty, as measured by the South African Multidimension Poverty Index (SAMPI) as well TB death rates in the neighbouring districts. Conclusion: The findings of this study revealed a statistically significant decrease in TB deaths and a disproportionate distribution of TB deaths among certain areas and population groups in South Africa. The existence of the identified inequalities in the burden of TB deaths calls for targeted public health interventions, policies, and resources to be directed towards the most vulnerable populations in South Africa.

scholarly journals Caucasian clover was more productive than white clover in grass mixtures under drought conditions

2000 ◽  
pp. 183-188 ◽  
Author(s):  
A.D. Black ◽  
R.J. Lucas
Keyword(s):  
White Clover ◽  
Festuca Arundinacea ◽  
Perennial Grass ◽  
Moisture Stress ◽  
Annual Rainfall ◽  
Grass Species ◽  
Pasture Production ◽  
Trifolium Ambiguum ◽  
Dry Conditions ◽  
Schedonorus Phoenix

This experiment compared the productivity of caucasian or white clover when established with five perennial grass species over 6 years in a dry lowland environment. Hexaploid 'Endura' caucasian clover or 'Grasslands Demand' white clover were sown in December 1994 with high endophyte 'Yatsyn' perennial ryegrass, 'Grasslands Wana' cocksfoot, 'Grasslands Advance' tall fescue, 'Grasslands Gala' grazing brome, or 'Grasslands Maru' phalaris into a deep, fertile silt loam. Initial establishment of clovers was poor with ryegrass and grazing brome. Some volunteer white clover established in all 10 treatments. After the first 14 months, no irrigation was applied over the following 4 years. Sheep grazed plots about six times each year. The legume cover in 15-month-old pastures was higher when sown with white clover (29%) than caucasian clover (21%) but dry conditions during 1997/1998 (60% of 680 mm mean annual rainfall) and 1998/1999 (66% of mean rainfall) decreased the percentage of legume in white clover pastures. In February 1998 and March 1999, legume contributed 37% and 21% of the dry matter (DM) in caucasian clover pastures, but only 4% and 1% in pastures sown with white clover. Rainfall during the sixth season (1999/2000) was more favourable (111% of mean rainfall). Total DM production from July 1999 to June 2000 was 10.0 t DM/ha from caucasian clover pastures and 8.7 t DM/ha from pastures sown with white clover. The mean proportion of legume in white clover pastures ranged from 9% when sown with ryegrass and phalaris to 1% with cocksfoot. In contrast, mean caucasian clover legume contents were similar across all grass treatments at 20%, but reached 46% with cocksfoot during summer. It was concluded that caucasian clover is more tolerant of summer moisture stress than white clover when in association with perennial grass species. Keywords: botanical composition, Bromus stamineus, Dactylis glomerata, legume content, Lolium perenne, moisture stress, pasture production, Phalaris aquatica, Schedonorus phoenix syn. Festuca arundinacea, Trifolium ambiguum, T. repens

scholarly journals Variability and Trends of Temperature and Rainfall Over Three Agro-Ecological Zones in North Shewa, Central Ethiopia

2020 ◽  
Author(s):  
Ashenafi Hailu Shekuru ◽  
Arega Bazezew Berlie ◽  
Yechale Kebede Bizuneh
Keyword(s):  
Crop Production ◽  
Smallholder Farmers ◽  
Annual Rainfall ◽  
Maximum Temperature ◽  
Upward Trend ◽  
Central Ethiopia ◽  
Ecological Zones ◽  
Annual Minimum Temperature ◽  
Rainfall Anomalies ◽  
Agro Ecological Zones

Abstract This study aims to analyze variability and trends of temperature and rainfall over three agro-ecological zones (AEZs) in Central Ethiopia. Gridded rainfall and temperature data, recorded on daily basis for 35 years (1979 - 2013) at 30 meteorological stations, were used for analysis. While Mann–Kendall test was applied to analyze the trends in rainfall and temperature, Sen’s slope estimator was used to determine the magnitude of change. The study detected an upward trend of 0.07°C/annum (p < 0.001) in mean annual maximum temperature at Kolla AEZ. It also showed an upward trend of 0.06/year (p < 0.001) for both Dega and Woina Dega AEZs. Mean annual minimum temperature exhibited an upward trend of 0.03°C/year at Kolla (p < 0.001), Woina Dega (p < 0.05), and Dega (p < 0.01), signifying a 1.05°C increase between 1979 and 2013. Results from precipitation concentration index (PCI) revealed highest percentage (97.1%) of irregular distributions in annual rainfall pattern at Kolla AEZ, followed by Woina Dega (82.9%). Standardized rainfall anomalies (SRA) computed in the study also showed higher percentage (28.6%) of drought in Kolla AEZ, which experienced drought once in every 3 or 4 years. The study revealed negative annual rainfall anomalies for 18 years in Kolla and 16 years in both Dega and Woina Dega AEZs. The reduced precipitation and rise in temperature could trigger wide-ranging influences on agricultural practices and crop production of smallholder farmers. Policymakers and stakeholders should give priority in designing and introducing pro-poor plus geographically differentiated adaptive strategies.

TIN-Copula bias correction of climate modeled daily maximum temperature in the MENA region

2021 ◽  
Author(s):  
Georgia Lazoglou ◽  
George Zittis ◽  
Panos Hadjinicolaou ◽  
Jos Lelieveld
Keyword(s):  
Hot Spot ◽  
Maximum Temperature ◽  
Daily Maximum Temperature ◽  
Dependence Structure ◽  
Daily Maximum ◽  
Model Output ◽  
Mena Region ◽  
Data Set ◽  
Variable Nature ◽  
Copula Method

&lt;p&gt;Over the last decades, the use of climate models in the projection and assessment of future climate conditions, both on global and regional scales, has become common practice. However, inevitable biases between the simulated model output and observed conditions remain, mainly due to the variable nature of the atmospheric system, and limitations in representing sub-grid-scale processes that need to be parameterized. The present study aims to test a new approach for increasing the accuracy of daily climate model output. We apply the recently introduced TIN-Copula statistical method to the results of a state-of-the-art global Earth System Model (Hadley Centre Global Environmental Model version 3 - HadGEM3). The TIN-Copula approach is a combination of Triangular Irregular Networks and Copulas that focuses on modeling the whole dependence structure of the studied variables. The study area of the current application is the Middle East and North Africa (MENA) region, a prominent global climate change hot-spot. Considering the lack of accurate and consistent observational records in the MENA, we used the ERA5 reanalysis dataset as a reference. The results of the study reveal that the TIN-Copula method significantly improves the simulation of maximum temperature, both on annual and seasonal time scales. Specifically, the HadGEM3 model tends to overestimate the ERA5 temperature data in the major part of the MENA region. This overestimation is mainly evident for the lower values of the studied data sets during all seasons, while in summer the overestimation is found in the whole data set. However, after the use the TIN-Copula method, the differences between the simulated maximum temperature and the ERA5 data were minimized in more than the 85% of the studied grids.&lt;/p&gt;

Clivia mirabilis (Amaryllidaceae: Haemantheae) a new species from Northern Cape, South Africa

Bothalia ◽  
2002 ◽  
Vol 32 (1) ◽  
pp. 1-7 ◽  
Author(s):  
J. P. Rourke
Keyword(s):  
South Africa ◽  
New Species ◽  
Vegetative Growth ◽  
Mediterranean Climate ◽  
Nature Reserve ◽  
Late Summer ◽  
Distribution Area ◽  
Early Autumn ◽  
Northern Cape ◽  
A New Species

Clivia mirabilis Rourke is a new pendulous tubular-flowered species from Oorlogskloof Nature Reserve in Northern Cape. Its distribution area is some 800 km outside the previously accepted range of the genus Clivia. This sun-tolerant species is adapted to an arid Mediterranean climate, producing vegetative growth in winter and maturing its seeds rapidly in late summer/early autumn to synchronize with the arrival of winter rains.

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