306 Abstracts

Does colour matter? Flower colour polymorphism, pollinator Radar data, Google Earth and Google Earth Engine were used in the visitation and reproductive success in the endemic petricola refinement of the forest layer.

S.L. Payne, C.T.S. Symes, E.T.F. Witkowski doi:10.1016/j.sajb.2018.02.110 School of Animal, and Environmental Sciences, University of the Witwatersrand, Private Bag 3, Wits 2050, Johannesburg, South Africa Do positive interactions expand the upper distributional limits of E-mail address: [email protected] (S.L. Payne) species on Marion Island?

Aloe petricola is a stemless aloe, endemic to Nelspruit and M.J. Raath, P.C. Le Roux surrounds (Mpumalanga Province, South Africa). During the winter Department of Plant and Soil Sciences, University of Pretoria, Private flowering period, individual produce different colour poly- Bag X20, Pretoria 0002, South Africa morphs, namely red-white, orange-yellow and red-yellow. The E-mail address: [email protected] (M.J. Raath) flowers suggest bird-pollination, and the aloe is regularly visited by birds; most frequently by Dark-capped Bulbul Pycnonotus Biotic interactions may strongly shape species’ distributions as tricolor, White-bellied Cinnyris talatala and Cape White-eye they contribute to determining species’ realized niches, potentially Zosterops virens. However, it is unclear if the birds are selecting either constraining or expanding the range of conditions under flowers based on the floral characteristics that might differ between which species occur. This study examined whether fine-scale plant- polymorphs. Visitors to in a sub-population of Aloe petricola plant interactions scale up to shape plant species distributions with varying colour polymorphs on Pullen Farm, 35 km east using Azorella selago Hook., a widespread cushion plant (compact, of Nelspruit, were recorded with camera traps during the flowering hemispherical plants that create favourable microhabitats by ame- season of 2017. volumes and concentrations were measured liorating stresses) and the rest of the vascular flora from the sub- for each polymorph. The effect of floral characteristics of the Antarctic Marion Island as a model system. We assessed the different colour polymorphs on bird visitation, as well as the elevational distribution of vascular plant species when growing in subsequent reproductive success, will be assessed. Other factors association or away from A. selago to test how the interaction with that could affect reproductive output will also be considered, this cushion plant species affect species’ ranges along: 1) twenty including individual plant size, distance between neighbouring, island-scale altitudinal transects, and 2) twenty-one landform-scale flowering A. petricola individuals and patch flowering density of the altitudinal transects. The upper distributional limits of most species sub-population. did not differ significantly in the presence and absence of A. selago at either spatial scale. However, at the island-scale, A. selago had a doi:10.1016/j.sajb.2018.02.109 positive effect on the upper range limit of one species, Aceana magellanica (mean difference = + 26 m), and had a strong positive effect on another species, Colobanthus kerguelensis (+ 104 m) in The significance of using satellite imagery to refine and assess transects located on the south slope aspect of the island. Therefore, issues within the forest component of the vegetation map of although A. selago strongly impacts some fine-scale species patterns, South Africa (VEGMAP 2012) these local impacts could only scale up to shape the distribution of certain vascular plant species on Marion Island. Thus, plant-plant M. Qabaqaba, A. Dayaram interactions have the potential to mediate range shifts by expanding ’ fl South African National Biodiversity Institute, Kirstenbosch National species upper distributional limits, although the in uence of these fi Botanical Gardens, Rhodes Drive, Newlands, Private Bag X7, Claremont interactions may be species-speci c. 7735, Cape Town, South Africa E-mail address: [email protected] (M. Qabaqaba) doi:10.1016/j.sajb.2018.02.111

The National Vegetation Map of South Africa, Lesotho and Swaziland (VEGMAP) is a map of groups of plant communities Fighting aging through elastase inhibition using South African across South Africa. The first time the communities were delineated aquatic plants was in 2006 and several different satellite images and techniques a a b a were used to delineate the extent of the plant communities. P.G. Radebe , B.D. Fibrich , B. Madikizela , N. Lall a Therefore, there were some inaccuracies in the delineation. Some Department of Plant and Soil Sciences, University of Pretoria, Pretoria of these inaccuracies were improved in the 2009 and 2012 VEGMAP 0002, South Africa b updates but some still remain. The Inaccuracies in the 2012 version Water Research Commission of South Africa, 4 Daventry Street, become evident when the layer is overlaid with satellite imagery. In Lynnwood Manor, Pretoria 0001, South Africa some cases forest areas are not mapped while in other scenarios E-mail address: [email protected] (P.G. Radebe) non-forest areas are mapped as Forest. While the mapping was a good approximation of forest, it still required improvements. Elastase is an enzyme belonging to the chymotrypsin family Improving the delineation of forests in the VEGMAP was one of of proteases. It is responsible for the degradation of the structural our focus areas for version 2017. Delineating forest extent using components of the dermis, such as elastin. After cleavage of elastin, satellite imagery and automated processes can be quicker and less elastase causes wrinkle formation and the skin starts to sag. Plants expensive, but it cannot be used to differentiate between forests are known to be a potential solution to fight skin aging, due to the and other structurally similar vegetation such as thicket. For these fact that certain plant extracts are capable of defending the skin from areas we needed to invest in the time consuming task of heads-up aging via the inhibition of enzymatic degradation. Nine indigenous digitising using the all available datasets (including historical South African aquatic plants were investigated for their potential to imagery where available) to make decisions about the texture, inhibit the activity of the elastase enzyme. These plants were chosen shape and pattern of forest patches. Basemaps from Esri ArcMap because the medicinal properties of South African aquatic plants are such as Landsat 8 views, the national South African imagery and not fully studied whereas most terrestrial plants are widely studied.