Newman E.,Stellenbosch University |
Manning J.,South African National Biodiversity Institute |
Anderson B.,Stellenbosch University
Annals of Botany | Year: 2014
Background and AimsPollinator landscapes, as determined by pollinator morphology/behaviour, can vary inter- or intraspecifically, imposing divergent selective pressures and leading to geographically divergent floral ecotypes. Assemblages of plants pollinated by the same pollinator (pollinator guilds) should exhibit convergence of floral traits because they are exposed to similar selective pressures. Both convergence and the formation of pollination ecotypes should lead to matching of traits among plants and their pollinators.MethodsWe examined 17 floral guild members pollinated in all or part of their range by Prosoeca longipennis, a long-proboscid fly with geographic variation in tongue length. Attractive floral traits such as colour, and nectar properties were recorded in populations across the range of each species. The length of floral reproductive parts, a mechanical fit trait, was recorded in each population to assess possible correlation with the mouthparts of the local pollinator. A multiple regression analysis was used to determine whether pollinators or abiotic factors provided the best explanation for variation in floral traits, and pollinator shifts were recorded in extralimital guild member populations.Key ResultsNine of the 17 species were visited by alternative pollinator species in other parts of their ranges, and these displayed differences in mechanical fit and attractive traits, suggesting putative pollination ecotypes. Plants pollinated by P. longipennis were similar in colour throughout the pollinator range. Tube length of floral guild members co-varied with the proboscis length of P. longipennis.ConclusionsPollinator shifts have resulted in geographically divergent pollinator ecotypes across the ranges of several guild members. However, within sites, unrelated plants pollinated by P. longipennis are similar in the length of their floral parts, most probably as a result of convergent evolution in response to pollinator morphology. Both of these lines of evidence suggest that pollinators play an important role in selecting for certain floral traits. © 2013 © The Author 2013. Published by Oxford University Press on behalf of the Annals of Botany Company. All rights reserved.
Tolley K.A.,South African National Biodiversity Institute |
Tolley K.A.,Stellenbosch University |
Townsend T.M.,San Diego State University |
Vences M.,TU Braunschweig
Proceedings of the Royal Society B: Biological Sciences | Year: 2013
Oceanic dispersal has emerged as an important factor contributing to bio-geographic patterns in numerous taxa. Chameleons are a clear example of this, as they are primarily found in Africa and Madagascar, but the age of the family is post-Gondwanan break-up. A Malagasy origin for the family has been suggested, yet this hypothesis has not been tested using modern biogeographic methods with a dated phylogeny. To examine competing hypotheses of African and Malagasy origins, we generated a dated phylogeny using between six and 13 genetic markers, for up to 174 taxa representing greater than 90 per cent of all named species. Using three different ancestral-state reconstruction methods (Bayesian and likelihood approaches), we show that the family most probably originated in Africa, with two separate oceanic dispersals to Madagascar during the Palaeocene and the Oligocene, when prevailing oceanic currents would have favoured eastward dispersal. Diversification of genus-level clades took place in the Eocene, and species-level diversification occurred primarily in the Oligocene. Plio-Pleistocene speciation is rare, resulting in a phylogeny dominated by palaeo-endemic species. We suggest that contraction and fragmentation of the Pan-African forest coupled to an increase in open habitats (savannah, grassland, heathland), since the Oligocene played a key role in diversification of this group through vicariance. © 2013 The Author(s) Published by the Royal Society. All rights reserved.
Agency: Cordis | Branch: FP7 | Program: CP-IP | Phase: ENV.2009.1.3.1.1 | Award Amount: 8.23M | Year: 2010
Fire regimes result from interactions between climate, land-use and land-cover (LULC), and socioeconomic factors, among other. These changed during the last decades, particularly around the Mediterranean. Our understanding of how they affected fire regime in the past is limited. During this century temperatures, drought and heat waves will very likely increase, and rainfall decrease. These and further socioeconomic change will affect LULC. Additional areas will be abandoned due to being unsuitable for agriculture or other uses. Fire danger and fire hazard are very likely to increase, affecting fire regimes. FUME will learn from the past to understand future impacts. Mod. 1 we will study how LULC and socioeconomics changed and how climate and weather affected fire in dynamically changing landscapes. Fires will be mapped throughout Europe to determine hazard burning functions for LULC types. Since climate has changed, an attempt to attribute (sensu IPCC) fire regime change to climate, differentiating it from socioeconomic change, will be made. Mod. 2 will produce scenarios of change (climate, including extremes, land-use land-cover, socioeconomics, vegetation) for various emissions pathways and three time-slices during this century. With these and results from Mod.1, models and field experiments projected impacts on fire-regime and vegetation vulnerabilities will be calculated, including climate extremes (drought, heat-waves). Mod. 3 will investigate adaptation options in fire- and land-management, including restoration. Fire prevention and fire fighting protocols will be tested/developed under the new conditions to mitigating fire risks. A company managing fire will be a key player. Costs and policy impacts of changes in fire will be studied. Research will focus on old and new fire areas, the rural interface, whole Europe and the Mediterranean, including all Mediterranean countries of the world. Users will be involved in training and other activities.
Sirami C.,South African National Biodiversity Institute |
Sirami C.,University of Cape Town |
Monadjem A.,University of Swaziland
Diversity and Distributions | Year: 2012
Aim: This study investigates changes in bird communities between 1998 and 2008 in four savanna sites in Swaziland and the extent to which shrub encroachment is responsible for these changes. Location: Swaziland, southern Africa. Methods: Generalized estimated equations were used to estimate changes in bird species occurrence between 1998 and 2008. Remote sensing of aerial photographs/satellite images was used to assess vegetation changes during the same period. We assessed the role of shrub encroachment for bird communities by testing the relationship between change in species occurrence and species habitat using a general linear model. We also estimated species richness, colonization and extinction and used general linear models to test the effects of vegetation changes on these parameters. Results: More than half of the bird species showed a significant change in occurrence between 1998 and 2008: 32 species increased and 29 decreased. Change in species occurrence was significantly explained by species habitat. Species significantly increasing were mainly associated with wooded savanna, whereas species significantly decreasing were mainly associated with open savanna. Species richness decreased significantly, and this decrease was significantly explained by shrub cover increase at the plot scale (from 24% to 44% on average). Extinction at the plot scale was significantly influenced by the loss of grass cover, while colonization at the plot scale was influenced by tree cover increase. Main conclusions: This study represents the first evidence of temporal changes in bird communities owing to shrub encroachment in southern Africa. Despite its short time frame (10years), this study shows dramatic changes in both vegetation structure and bird community composition. This confirms the general concern for southern African bird species associated with open savanna if current trends continue. © 2011 Blackwell Publishing Ltd.
Bond W.J.,University of Cape Town |
Midgley G.F.,South African National Biodiversity Institute
Philosophical Transactions of the Royal Society B: Biological Sciences | Year: 2012
Savannahs are a mixture of trees and grasses often occurring as alternate states to closed forests. Savannah fires are frequent where grass productivity is high in the wet season. Fires help maintain grassy vegetation where the climate is suitable for woodlands or forests. Saplings in savannahs are particularly vulnerable to topkill of above-ground biomass. Larger trees are more fire-resistant and suffer little damage when burnt. Recruitment to large mature tree size classes depends on sapling growth rates to fire-resistant sizes and the time between fires. Carbon dioxide (CO 2) can influence the growth rate of juvenile plants, thereby affecting tree recruitment and the conversion of open savannahs to woodlands. Trees have increased in many savannahs throughout the world, whereas some humid savannahs are being invaded by forests. CO 2 has been implicated in this woody increase but attribution to global drivers has been controversial where changes in grazing and fire have also occurred. We report on diverse tests of the magnitude of CO 2 effects on both ancient and modern ecosystems with a particular focus on African savannahs. Large increases in trees of mesic savannahs in the region cannot easily be explained by land use change but are consistent with experimental and simulation studies of CO 2 effects. Changes in arid savannahs seem less obviously linked to CO 2 effects and may be driven more by overgrazing. Large-scale shifts in the tree-grass balance in the past and the future need to be better understood. They not only have major impacts on the ecology of grassy ecosystems but also on Earth-atmosphere linkages and the global carbon cycle in ways that are still being discovered. © 2012 The Royal Society.
News Article | April 20, 2016
Macowania is a group of yellow daisy shrubs occurring in the alpine-like regions of the Drakensberg and highlands of Ethiopia, Eritrea and Yemen. Doctoral student Joanne Bentley, University of Cape Town, studied the genetic relationships between the various Macowania species and relatives during her Masters degree studies. Her research led to the first collection of the poorly known species Macowania revoluta (known also as the Amathole Macowania) in about 40 years. The story of Macowania revoluta is published in the open access journal PhytoKeys. The Amathole Macowania appears to be an exceptionally important keystone species. This is because it forms one of the dominant members of the valuable mountain wetland communities and, thus, likely plays a very important role in wetland functioning and soil protection. It appears to be somewhat tolerant of woody alien species and a valuable pioneer species protecting its native co-habitants. Plants like this one buffer more sensitive plants from sudden changes in environment (such as forestry, alien invasion and fire), and provide an opportunity for the ecosystem to 'bounce back'. Restricted to the Amathole mountains in the Eastern Cape Province, South Africa, the Amathole Macowania was first collected sometime before 1870 by the pioneer botanist Peter MacOwan, and was well documented until around 1949. After that, except for one record in 1976, the plant quietly disappeared. "This was the first Macowania species that we found during our fieldtrip across the greater Drakensberg. We had combed several of the localities where it had been collected before; mostly from several decades ago, some from more than a century ago!" says Joanne Bentley. "We became increasingly doubtful about finding the plant, given the heavily transformed plantation landscape." "Ready to throw in the towel, we came across a peaty area on the margins of the forest and decided on one last investigation. We were lucky: it was growing prolifically! It was a very special moment." As it often happens, exciting discoveries come in bulk. Joanne's discovery of the plant in July 2010 was followed by another record in October 2010, by the Curator of the Schonland Herbarium, Tony Dold. In 2014 at least three additional localities were recorded along the popular Amathole Hiking Trail by Dr Ralph Clark, Rhodes University. A further record was added in 2015 by Vathi Zikishe, South African National Biodiversity Institute. The verdict: this is a very localised but patchily abundant species, and an ecologically valuable component of the Amathole flora. Listed as 'Data Deficient' in the Threated Plants List for South Africa, this string of modern records of the species also provided the first opportunity to get an idea of its ecology and abundance, as well as the first photographs. "The practical value of this species in local land restoration projects still needs to be explored, but the opportunities are exciting," says Dr Clark. "The discovery that this obscure endemic mountain plant is not only abundant, but is, in fact, fulfilling an extremely important ecological role, highlights the value of detailed mountain biodiversity research in southern Africa." Explore further: Pearl-flowered legume a surprise new find in the Cape Snowy Mountains, South Africa
News Article | January 27, 2016
The brown and green chameleon with scattered blue spots was found in four montane forest patches in the Udzungwa Mountains and Southern Highlands. The species, Kinyongia msuyae, is named for Charles A. Msuya, a pioneer of Tanzanian herpetology who collected the first known specimen attributable to this species and has spent most of his life studying Tanzania's reptiles and amphibians. The chameleon is described in the journal Acta Herpetologica 10(2): 111-120, 2015. Authors of the study include: Michele Menegon of the Museo delle Scienze in Trento, Italy; Simon P. Loader of the University of Roehampton in London; Tim Davenport and Sophy Machaga of WCS; Kim M. Howell of the University of Dar es Salaam; Colin R. Tilbury of South African National Biodiversity Institute; and Krystal A. Tolley University of Stellenbosch in South Africa. The authors say the discovery sheds more light on a region called the Makambako Gap, a supposed zoological barrier between the distinct faunas of the Southern Highlands and Eastern Arc Mountains that Davenport and WCS have long argued doesn't exist. Evidence from this new species points to even closer biological affinities between the Udzungwa and the Livingstone Mountains of the Southern Highlands. Tanzania's Southern Highlands has emerged as a hotbed of new discoveries in recent years. In 2003, WCS discovered the kipunji - a species of primate that turned out to be an entirely new genus - a first for Africa since 1923. And in 2012, WCS found Matilda's horned viper, a new variety of snake. "Along with our discoveries of the Kipunji, Matilda's horned viper and other reptiles and frogs, this new chameleon really seals the deal as regards the boundary of the Eastern Arcs," said Tim Davenport, Director of WCS's Tanzania Program and co-discoverer of the new chameleon. "It is very clear now that the so-called Makambako Gap doesn't exist zoologically, and that the Southern Highlands is every bit as biodiverse and endemic-rich as all other Eastern Arc Mountains. With its own unique fauna and flora the region thus warrants as much protection as we can possibly afford it."
Roux J.P.,South African National Biodiversity Institute
Adansonia | Year: 2011
Based on detailed morphological studies of a large number of herbarium specimens from various herbaria, a review of the fern genera Dryopteris and Nothoperanema in Madagascar and neighbouring Indian Ocean islands, including Saint Paul, is presented. Eleven species and a putative hybrid are recorded for the region, seven of these are considered endemic to the region. © Publications Scientifiques du Muséum national d'Histoire naturelle, Paris.
Roux J.P.,South African National Biodiversity Institute
Botanical Journal of the Linnean Society | Year: 2011
Elaphoglossum section Lepidoglossa in Africa, Macaronesia (Azores and Madeira), the mid-Atlantic Ocean Islands (St Helena, Gough and Tristan da Cunha Island groups) and the southern Indian Ocean Islands (Marion and Prince Edward Islands) is reviewed. Fifteen Elaphoglossum species from this region are ascribed to the section. A new species, Elaphoglossum rivularum, confined to the Chimanimani Mountains in eastern Zimbabwe and formerly ascribed to E. kuhnii from West Africa, is described. © 2010 The Linnean Society of London.
Ochyra R.,Polish Academy of Sciences |
Van Rooy J.,South African National Biodiversity Institute
Cryptogamie, Bryologie | Year: 2013
Bucklandiella lamprocarpa (Miill.Hal.) Bednarek-Ochyra & Ochyra is the only rheophytic representative of the genus in South Africa. Although this distinct and almost unmistakable species is bipolar in distribution, it is mostly an austral cool-temperate species ranging northwards along the alpine belts of South America and Africa. Examples are given of pan-Holantarctic mosses in the Cape Floristic Region and hypotheses put forward to explain this distribution pattern. The South African distribution of B. lamprocarpa is mapped and described in detail. © 2013 Adac. Tous droits réservés.