scholarly journals Isolepis namaquana (Cypereae, Cyperaceae), a new endemic species from the winter rainfall area of South Africa

2011 ◽  
Vol 77 (1) ◽  
pp. 55-58 ◽  
Author(s):  
A.M. Muasya ◽  
J. Viljoen ◽  
C.H. Stirton
Author(s):  
Karen J. Esler ◽  
Anna L. Jacobsen ◽  
R. Brandon Pratt

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.


Phytotaxa ◽  
2014 ◽  
Vol 177 (5) ◽  
pp. 261 ◽  
Author(s):  
Neil R. Crouch ◽  
Mario Martínez-Azorín ◽  
Angela J. Beaumont ◽  
David Styles

A new South African endemic species, Stellarioides littoralis is described and illustrated, with data provided on morphology, ecology and distribution. The species appears to be closely related to S. longibracteata and whilst it shares in common an epigeal habit of the bulb with the latter species, several reproductive and vegetative morphological features clearly distinguish it. The affinities and divergences with other close allies are also discussed.


2021 ◽  
Vol 38 (5) ◽  
pp. 411-415
Author(s):  
Vhuthu Ndou ◽  
Ethel E Phiri ◽  
Frederik H Eksteen ◽  
Petrus J Pieterse

2013 ◽  
Vol 9 (3) ◽  
pp. 2309-2356 ◽  
Author(s):  
S. Weldeab ◽  
J.-B. W. Stuut ◽  
R. R. Schneider ◽  
W. Siebel

Abstract. We established a multi-proxy time series comprising analyses of major elements in bulk sediments, Sr and Nd isotopes and grain size of terrigenous fraction, and δ18O and δ13C in tests of Neogloboquadrina pachyderma (sinistral) from a marine sediment sequence recovered off the Orange River. The records reveal coherent patterns of variability that reflect changes in wind strength, precipitation over the river catchments, and upwelling of cold and nutrient-rich coastal waters off western South Africa. The wettest episode of the Holocene in the Winter Rainfall Zone (WRZ) of South Africa occurred during the "Little Ice Age" (700–100 yr BP). Wet phases were accompanied by strengthened coastal water upwellings, a decrease of Agulhas water leakage into the southern Atlantic, and a reduced dust incursion over Antarctica. A continuous aridification trend in the WRZ and a weakening of the southern Benguela Upwelling System (BUS) between 9000 and 5500 yr BP parallel with increase of dust deposition over Antarctica and an enhanced leakage of warm Agulhas water into the southeastern Atlantic. The temporal relationship between precipitation changes in the WRZ, the thermal state of the coastal surface water, and leakage of warm water in southern Atlantic, and variation of dust incursion over Antarctica suggests a causal link that most likely was related to latitudinal shifts of the Southern Hemisphere westerlies. Our results of the mid-Holocene time interval may serve as an analogue to a possible long-term consequence of the current and future southward shift of the westerlies that may result in a decline of rainfall over southwest Africa and a weakened upwelling with implication for phytoplankton productivity and fish stocks. Furthermore, warming of the coastal surface water as a result of warm Agulhas water incursion into the southern BUS may affect coastal fog formation that is critical as moisture source for the endemic flora of the Namaqualand.


2018 ◽  
Vol 19 (1) ◽  
pp. 127-142 ◽  
Author(s):  
R. C. Blamey ◽  
A. M. Ramos ◽  
R. M. Trigo ◽  
R. Tomé ◽  
C. J. C. Reason

Abstract A climatology of atmospheric rivers (ARs) impinging on the west coast of South Africa (29°–34.5°S) during the austral winter months (April–September) was developed for the period 1979–2014 using an automated detection algorithm and two reanalysis products as input. The two products show relatively good agreement, with 10–15 persistent ARs (lasting 18 h or longer) occurring on average per winter and nearly two-thirds of these systems occurring poleward of 35°S. The relationship between persistent AR activity and winter rainfall is demonstrated using South African Weather Service rainfall data. Most stations positioned in areas of high topography contained the highest percentage of rainfall contributed by persistent ARs, whereas stations downwind, to the east of the major topographic barriers, had the lowest contributions. Extreme rainfall days in the region are also ranked by their magnitude and spatial extent. The results suggest that although persistent ARs are important contributors to heavy rainfall events, they are not necessarily a prerequisite. It is found that around 70% of the top 50 daily winter rainfall extremes in South Africa were in some way linked to ARs (both persistent and nonpersistent). Overall, the findings of this study support similar investigations on ARs in the North Atlantic and North Pacific.


Bothalia ◽  
2009 ◽  
Vol 39 (1) ◽  
pp. 73-85 ◽  
Author(s):  
M. Becker ◽  
F. Albers

This contribution deals with the taxonomy and phylogeny of the  Pelargonium carnosum complex, a group of closely related taxa of Pelargonium L’Hér. section  Otidia (Sweet) DC. (Geraniaceae) that is distributed in the winter rainfall area of South Africa. According to molecular analyses via AFLP, P. adriaanii M.Becker F.AIbers,  P. carnosum (L.) L’Uér., P.  ferulaceum (C'av.) Willd. and P. polycephalum (E.Mey. ex Harv.) R.Knuth form a monophyletic clade. Although hybridization may occur between the taxa, three are assigned to specific rank. The fourth taxon, P. ferulaceum is recognized as a subspecies ot'P carnosum. As is implied from the occurrence of morphological intermediates and partly from molecular evidence,hybridization does not only occur among the taxa in this complex but also involves species closely related to this group  (P. panifiorum J.C.Wendl., P. laxum (Sweet) G.Don, P. dasyphyllum R.Knuth). For the taxa in the P. carnosum complex, distribution areas are delineated and diagnostic features that have until now remained obscure, are outlined.


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