Photographic evidence of fire-induced shifts from dwarf-shrub- to grass-dominated vegetation in Nama-Karoo.
South African Journal of Botany 101 (November 2015): 148-152. https://doi.org/10.1016/j.sajb.2015.06.002
The Nama-Karoo is a semi-arid inland biome in South Africa dominated by dwarf shrubs with grasses, shrubs, geophytes and herbs at varying levels of abundance. The position of the Nama-Karoo/grassland boundary is determined in part by rainfall amount, and in recent years there has been an increase in grassiness, correlated with good rains. This has allowed wildfires, an unusual occurrence, to burn at several sites in the central and eastern regions of the biome. The general effect of fire has been to convert dwarf shrublands to grassland with the extirpation of several nonsprouters species. A collection of photographs describes this effect. It is anticipated that these nonsprouters will recolonise by seed over time, but could be eliminated if fire frequency is high enough to eliminate their seedbank. It is predicted that if grassy conditions persist in the Nama-Karoo, then fire will be an important factor that shapes the Nama-Karoo/grassland boundary.
On the origin of southern African subtropical thicket vegetation.
South African Journal of Botany 2005, 71(1): 1–23.
Volltext (PDF): https://core.ac.uk/download/pdf/82504194.pdf
The origin and affinities of southern African subtropicalt hicket have been misunderstood and neglected. This formation was only recognised as a biome distinct from savanna and karoo in the mid 1990s. One hypothesis states that it is a young vegetation type, assembled from forest, savanna and karoo elements after Holoceneclimatic amelioration. Others have suggested anancient history for thicket. Here we review fossil and phylogenetic data in order to provide a better assessment of the origins of thicket. Albeit patchy, thefossil data are suggestive of a Palaeogene origin for this formation. A review of molecular phylogenetic data of extant thicket lineages indicated three major patterns:(i) ancient Cretaceous elements, including Encephalartos and the Strelitziaceae, (ii) basally branching lineages — many of which dominate contemporary thicket — that evolved in the Eocene (e.g.in the Celastraceae, Sapindaceae, Didiereaceae, Crassulaceae: Cotyledonoideae), and (iii) lineages derived from adjacent biomes that diversified in thicket in association with Neogene climatic deterioration (e.g. Aizoaceae, Asteraceae). We provide a narrative account of the evolution of thicket, which concludes that it is an ancient formation, extending back at least to the Eocene and derived initially from elements in the forest formations that prevailed in Upper Cretaceous and early Palaeogene times. As a biome, thicket is not uniquely southern African, being part of a formation that was globally widespread in the Eocene and which is extant in many parts of the world. Future research on the origins of thicket should focus on providing dates for major dichotomies as a complement to the rapid emergence of molecular phylogenies, as well as data on the genetic variation in populations of taxa categorised as ancient or young, and widespread or range-restricted.
Forest Vegetation of Northern Japan and the Southern Kurils.
In: KOLBEK, J. et al.: Forest Vegetation of Northeast Asia: 231-261.
Geobnotany Series Vol. 28. Springer Science+Business Media Dordrecht.
ISBN 978-90-481-6312-0; ISBN 978-94-017-0143-3 (eBook); DOI 10.1007/978-94-017-0143-3.
The composition and geographical distribution of major forest types of northern Japan, including the southem Kuril Islands, are summarized, along with phytogeographical relationships of the major forest types to the forests of the adjacent Korean Peninsula, northeastern China and the Russian Far East. Two major forest zones appear, a cool-temperate forest zone and a boreal forest zone, as well as a subalpine forest belt in mountains of northern Japan. The cool-temperate forest zone includes five major climax forest types: Fagus japonica forest, Quercus serrata forest, Fagus crenata forest, Quercus mongolica forest and Abies sachalinensis-Quercus mongolica forest. This zone covers almost all of lowland northern Japan. The boreal forest zone includes three major climax forest types: Picea jezoensis-Abies sachalinensis forest, Picea glehnii forest and Larix gmelinii forest. This zone occurs in central Hokkaido and on the southern Kuril Islands. The subalpine forest belt includes three major forest types: Abies mariesii forest, Betula ermanii forest and Pinus pumila thicket. Phytogeographically, the Quercus serrata forest and Quercus mongolica forest are the principal forest types of cool-temperate deciduous broad-leaved forest in northeastern Asia. The Fagus crenata forest is a snow-induced, non-zonal climax. The Abies sachalinensis-Quercus mongolica forest is the most essential forest type of the Pan-Mixed Forest Zone (sensu Tatewaki), together with the Quercus mongolica forest. The Picea jezoensis-Abies sachalinensis forest composes the eastern and southernmost extension of the boreal evergreen forest zone in northeastern Asia. The subalpine Abies mariesii forest is endemic to northern Japan, while the Betula ermanii forest occupies the area of highly oceanic climate in northeastern Asia. Finns punula thicket is a homologue of the Larix gmelinii-Pinus pumila forest in continental northeastern Asia. The south to north zonation of forest types in lowland northern Japan corresponds to the following sequence: Quercus serrata forest, Quercus mongolica forest, Abies sachalinensis-Quercus mongolica forest, and Picea jezoensis-,Abies sachalinensis forest.
Die Ufervegetation - Geschichte, Funktionen und Pflege.
Broschüre, 12 Seiten, 17 Fotos / Grafiken.
FAUNAFOCUS 28/2016. Hrsg.: Wildtier Schweiz.
Fliessgewässer – und seien sie noch so klein – sind wichtige Verbindungsachsen in stark genutzten Landschaften, sofern sie von einer strukturreichen, natürlichen Ufervegetation begleitet werden. Wo Wasser und Land eng verzahnt ineinandergreifen, entstehen sehr artenreiche Lebensräume, Leitlinien mit guter Deckung für mobile Tiere, Kinderstuben und Verstecke für Fische, Krebse und kleine Wasserlebewesen. Auch viele Pflanzen nutzen den Uferstreifen als Ausbreitungsweg. Heute ist die Ufervegetation zwar oft zerstört, doch kann sie wieder ihre angestammte Funktion übernehmen, wenn sie entsprechend gestaltet und gepflegt wird. Wie das geht und was dabei zu beachten ist, wurde von Irene Weinberger in der neuesten Ausgabe von FaunaFocus sehr anschaulich dargestellt.
Impact of the black rhinoceros (Diceros bicornis minor ) on a local population of Euphorbia bothae in the Great Fish River Reserve, South Africa.
African Journal of Ecology 47 (4): 509–517, December 2009
In the Great Fish River Reserve, South Africa, black rhinoceros (Diceros bicornis minor) feed extensively on a local population of Euphorbia bothae. Maintaining the endangered black rhinoceros and the protected E. bothae population are both conservation priorities of the reserve. Therefore, the sustainability of this plant–animal interaction was investigated by comparing population characteristics, browsing incidence and intensity within the reserve and in an adjacent exclosure without access to rhino. Fixed-point photographs showed that over a 2-month period 36.6% of 213 monitored plants were browsed, with an average biomass loss of 13%, and 1% were destroyed. Of 26 plants re-photographed after approximately 3 years, 70% showed a decrease in biomass, averaging 37.8% over this period. In this time span, 19% of the monitored plants died. Small plants (<45 cm) were over-represented in the rhino-browsed area, whereas the fraction of reproductively active plants and overall plant density were found to be lower than in the adjacent exclosure. No evidence of short-term compensatory growth in response to browsing was found for E. bothae. This study indicates that, with the current population size, rhinos are overexploiting the E. bothae population and special measures should be taken to prevent local extinction.
Continued decline in tree euphorbias (Euphorbia tetragona and E. triangularis) on the Great Fish River Reserve, Eastern Cape, South Africa.
African Journal of Ecology 48 (4): 923–929.
Article first published online: 10 NOV 2010
A dramatic decline averaging 43% over a 4-year period has occurred in tree Euphorbia (Euphorbia tetragona and Euphorbia triangularis) populations on the Great Fish River Reserve, South Africa. These changes are evident from data gathered by general vegetation monitoring methods as well as from a focused study of four tree Euphorbia populations. The decline from 2003 to 2007 was more marked for E. triangularis than for E. tetragona and was accompanied by a general absence of seedlings and a reduced presence of younger age classes of both species, decreasing the proportion of younger trees in the populations. The role of megaherbivores, specifically the black rhinoceros, in these changes is well established. However, the impact of baboon activity, leading to damage to tree crowns and upper branches, is also substantial, especially on E. triangularis populations. Damaged crowns were recorded significantly more often for E. triangularis than for E. tetragona, and the damage frequency increased with decreasing tree height. Thus, our work provides the first evidence that these two closely related Euphorbia species may be affected differently by herbivory.
Alien trees, shrubs and creepers invading indigenous vegetation in the Hluhluwe-Umfolozi game reserve complex in Natal.
Bothalia 1983 Vol. 14 No. 3/4 pp. 949-959. ISSN 0006-8241.
The results of a survey and monitoring programme conducted in the Hluhluwe-Umfolozi Game Reserve Complex in Natal are presented. The area consists of 900 km2 of savanna and forest vegetation. Twenty alien tree, shrub and creeper species currently invading indigenous vegetation within the Complex are listed. Herbaceous aliens were not surveyed. An analysis of the habitats being invaded by these alien plants is presented and it is concluded that riverine and forest-edge habitats are those most seriously threatened by alien plant infestations. The distribution, nature and history of the infestations of each species are summarized. Distribution maps given for the eight species which are currently most important in the Complex. The potential threat posed by each species is estimated and the species are ranked in order of priority for contro action. The South American composite, Chromolaena (Eupatorium) odorata, is identified as being the alien species currently posing the greatest threat to natural vegetation in the Complex. The Asian tree, Melia azedarach, is considered the second most important alien species invading the area. It is concluded that both these species should be declared noxious weeds throughout the Republic and that research into their biological control is urgently required.
Das Naturschutzgebiet Federsee. Ein Führer durch Landschaftsgeschichte und Ökologie.
Silberburg Verlag, Tübingen. ISBN 978-3-87407-747-7. 126 Seiten Brosch.
Das Federseemoor in Oberschwaben ist das größte zusammenhängende Moorgebiet in Baden-Württemberg und damit eine der faszinierendsten Landschaften Südwestdeutschlands. Der neue Naturführer von Hans Günzl erklärt anschaulich die ökologischen Zusammenhänge dieser sensiblen Naturlandschaft. Das völlig neu überarbeitete Standardwerk des Ökologen und Zoologen Hans Günzl ist sowohl fachkundiger Naturführer als auch spannendes Lesebuch zugleich. Das reich bebilderte Buch gehört in die Tasche eines jeden Federsee-Besuchers.
Africa - A Natural History.
170 Seiten, 300 Farbfotos, Landkarten.
Southern Book Publishers (Pty.) Ltd. ISBN 1-86812-520-3.
Documenting the wild variance and natural extravagance of the African continent, this book takes the reader on a journey through the seven major habitats of Africa: savanna, dryland, forest, highland, Cape heathland, the fresh waters, and the coastal zones. Detailed descriptions of the mammals, birds, reptiles and amphibians, fish and vegetation that make each habitat their home, accompany each chapter.