Analysis of trends, recurrences, severity and frequency of droughts using standardised precipitation index: Case of OR Tambo District Municipality, Eastern Cape, South Africa

Abstract

South Africa is susceptible to droughts. However, little documentation exists on drought occurrence in South Africa at national, provincial and municipal administrative boundaries. This study profiles hydrological drought in OR Tambo District Municipality from 1998 to 2018, computing frequency, severity and intensity in order to show areas of high vulnerability. Data used were obtained from South African Weather Services. Standardised precipitation index (SPI) was calculated using the Meteorological Drought Monitor (MDM) software. Results showed a wide variation in monthly precipitation throughout the year. Coastal areas receive higher rainfall than inland municipalities. The study revealed that Nyandeni experienced the highest drought frequency of 62%, Mhlontlo (58%), King Sabatha Dalindyebo Municipality (57%), Ngquza Hill (55%) and Port St Johns Municipality showing the least at 52%. Hydrological drought severity frequency and duration varied between seven days and nine weeks. Drought intensity class exposed the annual average intensity for the five local municipalities represented as follows: KSDM (–0.71), PSJM (–0.99), Ngquza Hill (–0.81), Nyandeni (–0.71) and Mhlontlo (–0.62). The longest drought duration across OR Tambo was experienced in 2014 with durations varying from 3 to 11 weeks across the municipalities. OR Tambo District Municipality is susceptible to hydrological droughts and the extent varies across local municipalities. Results could be used for both adaptation planning and mitigating the impacts of future droughts. In addition, they could assist in guiding allocation of drought relief resources in ways that prioritise drought prone and vulnerable municipality.

Review of In-Situ and Remote Sensing-Based Indices and Their Applicability for Integrated Drought Monitoring in South Africa

“…This information is crucial for preparedness, adaptation, and mitigating the impacts of future droughts at the local municipality scale. The authors concurred with Tfwala et al (2018) and Botai et al (2016), amongst others, that the SPI has a potential to be a useful tool when forecasting and estimating the frequency, duration, and intensity of droughts [54].…”

Fungal Species and Mycotoxins Associated with Maize Ear Rots Collected from the Eastern Cape in South Africa

“…For example, the AN district will experience cooler climatic conditions as it is found at a higher elevation close to a mountainous region [ 79 ]. The ORT district however experiences more humid conditions and moderate-to-high rainfall along its sub-tropical coast, but it also has pockets of mountainous areas [ 80 ]. Suboptimal environmental conditions can contribute to mycotoxins not being present at the two farms that had ear rots and mycotoxigenic species present.…”

The critical role of coastal protected areas in buffering impacts of extreme climatic conditions on bird diversity and their ecosystem services' provisioning in the Eastern Cape Province, South Africa

“…This finding is consistent with Karr (1976) who reported that seasonal variation in avian community structure decreases with increasing vegetation complexity—indeed, the Eastern Cape Wild Coast preserves complex and threatened vegetation patches (Mucina & Rutherford, 2006; Skowno et al, 2019). The coastal areas have climates that are more humid than inland climates in the Eastern Cape Province (Nkamisa et al, 2022; Landman et al, 2017), which has positive effects on plant‐based food recourses as well as the invertebrates (Karr, 1976): all of these may attract inland birds during periods of drought and food scarcity. Consistently, we found significantly higher records of bird species in 2018/2019 than in other years, which is partly because of a combination of observed extreme drought conditions and arrival of the migrant bird species.…”