Syd Ramdhani

The World's Zoogeographical Regions Confirmed by Cross-Taxon Analyses

The worlds zoogeographical regions were historically defined on an intuitive basis, with no or a limited amount of analytical testing. Here, we aimed (a) to compare analytically defined global zoogeographical clusters for the herpetofauna, birds, mammals, and all these groups taken together (tetrapod vertebrates); (b) to use commonalities among these groups to propose an updated global zoogeographical regionalization; and (c) to describe the resulting regions in terms of vertebrate diversity and characteristic taxa. The clusters were remarkably uniform across taxa and similar to previous intuitively defined regions. Eleven vertebrate-rich (Nearctic, Caribbean, Neotropical, Andean, Palearctic, Afrotropical, Madagascan, Indo-Malaysian, Wallacean, New Guinean, Australian) and three vertebrate-poor (Arctic, Antarctic, Polynesian) zoogeographical regions were derived; the Neotropical, Afrotropical, and Australian had the highest numbers of characteristic tetrapod genera. This updated regionalization provides analytically accurate divisions of the world, relevant to conservation, biogeographical research, and geography education.

Effects of simulated acid rain on germination, seedling growth and oxidative metabolism of recalcitrant‐seeded Trichilia dregeana grown in its natural seed bank

Increased air pollution in a number of developing African countries, together with the reports of vegetation damage typically associated with acid precipitation in commercial forests in South Africa, has raised concerns over the potential impacts of acid rain on natural vegetation in these countries. Recalcitrant (i.e. desiccation sensitive) seeds of many indigenous African species, e.g. must germinate shortly after shedding and hence, may not be able to avoid exposure to acid rain in polluted areas. This study investigated the effects of simulated acid rain (rainwater with pH adjusted to pH 3.0 and 4.5 with 70:30, H2 SO4 :HNO3 ) on germination, seedling growth and oxidative metabolism in a recalcitrant-seeded African tree species Trichilia dregeana Sond., growing in its natural seed bank. The results suggest that acid rain did not compromise T. dregeana seed germination and seedling establishment significantly, relative to the control (non-acidified rainwater). However, pH 3.0 treated seedlings exhibited signs of stress typically associated with acid rain: leaf tip necrosis, abnormal bilobed leaf tips, leaf necrotic spots and chlorosis, reduced leaf chlorophyll concentration, increased stomatal density and indications of oxidative stress. This may explain why total and root biomass of pH 3.0 treated seedlings were significantly lower than the control. Acid rain also induced changes in the species composition and relative abundance of the different life forms emerging from T. dregeanas natural seed bank and in this way could indirectly impact on T. dregeana seedling establishment success.

Phylogeography of Schotia (Fabaceae): Recent Evolutionary Processes in an Ancient Thicket Biome Lineage

Schotia has a southern African distribution with a strong affinity to the thicket biome and is a potential indicator of thicket biogeography. This study uses DNA sequence data (from the chloroplast and nuclear genomes) to infer interspecific phylogenetic relationships, to elucidate the evolutionary history of Schotia, and to extrapolate findings to the history of the thicket biome. Four species of Schotia represented by multiple samples were nonmonophyletic for both chloroplast and nuclear markers. These results may be due to hybridization and/or incomplete lineage sorting, which also suggests a recent origin of Schotia morphospecies. The center of genetic and taxonomic diversity of Schotia is the Eastern Cape and partly the Western Cape, coinciding with the hub of present‐day thicket distribution. This region is hypothesized as being a refugial area for Schotia (and the associated thicket biome) during glacial periods, with expansion beyond this region during interglacial periods.

Global hotspots in the present-day distribution of ancient animal and plant lineages

The current distribution of biotic lineages that emerged in the deep time has both theoretical and practical implications, in particular for understanding the processes that have forged present-day biodiversity and informing local and regional-scale conservation efforts. To date however, there has been no examination of such patterns globally across taxa and geological time. Here we map the diversity of selected extant seed plant and tetrapod vertebrate lineages that were already in existence either in the latest Triassic or latest Cretaceous. For Triassic-age linages, we find concentrations in several regions – both tropical and temperate – parts of North America, Europe, East and South-east Asia, northern South America, and New Zealand. With Cretaceous-age lineages, high values are relatively uniformly distributed across the tropics, with peak the values along the Andes, in South-east Asia and Queensland, but also in the temperate Cape Mountains. These patterns result from a combination of factors, including land area, geographic isolation, climate stability and mass extinction survival ability. While the need to protect many of these lineages has been long recognised, a spatially-explicit approach is critical for understanding and maintaining the factors responsible for their persistence, and this will need to be taken forward across finer scales.

Epiphyte diversity on host trees in an urban environment, eThekwini Municipal Area, South Africa

Vascular epiphytes live non-parasitically on other plants and are a distinctive and intergral component of tropical forests. There is a general lack of studies examining epiphyte diversity in urban settings. The aim of this study was to document the diversity of epiphytes on host trees in the eThekwini Metropolitan Area (EMA). In addition, the number of individuals of each epiphyte, host tree circumference at breast height and height were recorded. In total, 30 epiphyte species from 12 families were recorded, with most epiphyte species belonging to the Moraceae (n = 8) and Araliaceae (n = 5). A total of 34 host species from 15 families were recorded. These numbers did not increase when considering herbarium material within the EMA sensu stricto. The highest epiphyte richness (n = 13) was reported on the palm Raphia australis. The high number of both alien host and epiphytic taxa are of concern. More studies are needed to understand how epiphyte/host interactions in the urban landscape are established and maintained.

How do alien plants fit in the space-phylogeny matrix?

Recent advances in the field of plant community phylogenetics and invasion phylogenetics are mostly based on plot-level data, which do not take into consideration the spatial arrangement of individual plants within the plot. Here we use within-plot plant coordinates to investigate the link between the physical distance separating plants, and their phylogenetic relatedness. We look at two vegetation types (forest and grassland, similar in species richness and in the proportion of alien invasive plants) in subtropical coastal KwaZulu-Natal, South Africa. The relationship between phylogenetic distance and physical distance is weak in grassland (characterised by higher plant densities and low phylogenetic diversity), and varies substantially in forest vegetation (variable plant density, higher phylogenetic diversity). There is no significant relationship between the proportion of alien plants in the plots and the strength of the physical-phylogenetic distance relationship, suggesting that alien plants are well integrated in the local spatial-phylogenetic landscape.

Vertebrate endemism in south-eastern Africa numerically redefines a biodiversity hotspot

We use numerical methods to explore patterns of vertebrate endemism in south-eastern Africa, refining the boundaries of the intuitively-defined Maputaland-Pondoland-Albany biodiversity hotspot, also proposing a zoogeographic regionalisation. An incidence matrix of 300 vertebrate species endemic to south-eastern Africa sensu lato in 37 operational geographic units were used in (a) phenetic cluster analysis (PCA) using the algorithm of unweighted pair-group method with arithmetic averages (phenetic approach), and (b) parsimony analysis of endemicity (PAE; parsimony approach), in order to numerically evaluate the bioregional delimitations. The analyses provide a valid biogeographical entity 37% larger than the Maputaland-Pondoland-Albany hotspot, but substantially (131%) higher in vertebrate endemicity viz. the Greater Maputaland-Pondoland-Albany (GMPA) region of vertebrate endemism. South-east Africa is recognised as a dominion in the global zoogeographical area hierarchy, with subordinate units including the GMPA province. Various spatially-based measures of endemism were mapped for vertebrate species restricted to the dominion, i.e. endemic to south-eastern Africa sensu stricto. Areas and centres of endemism detected respectively from PAE and PCA, within the south-east Africa dominion also support the refined boundary of the GMPA region of endemism, which provides a better spatial conservation priority compared to the Maputaland-Pondoland-Albany hotspot. Reptiles and amphibians are found to be the main drivers of the overall pattern of endemism, while the pattern in freshwater fish is the most distinctive. Our analyses also indicate a good congruence of the centres of endemism across different terrestrial vertebrate taxa.

Maize and pea germination and seedling growth responses to compost generated from biowaste of selected invasive alien plant species

Abstract Plant biowaste of alien species represents a potential resource for compost production. This study investigated the seed and seedling responses of maize and pea to composts generated from the biowaste of four invasive species in eThekwini, South Africa: Acacia podalyriifolia, Hedychium gardnerianum, Litsea glutinosa, and Tithonia diversifolia. Except for a 40% concentration of T. diversifolia, leachates of the biowaste from the four species had no marked effects on germination. In seedling growth studies, Berea Red soil (control) was supplemented with composts produced using combinations of the four species (A. podalyriifolia + T. diversifolia [T1], A. podalyriifolia + H. gardnerianum [T2], L. glutinosa + T. diversifolia [T3], and L. glutinosa + H. gardnerianum [T4]), and a commercial compost (T5). Carbon and nitrogen levels of the biowaste composts were higher than the control, while their associated C/N ratios were low enough to encourage microbial growth, facilitate rapid decomposition, and support plant growth. A comparison of percentage seedling production, growth rate, and biomass production between the commercial compost and alien biowaste treatments revealed all parameters to be statistically comparable among T5, T1, and T3 for maize, and between T5 and T1 for pea. These superior biowaste composts did not enhance growth relative to the commercial compost, but supported growth to the same extent. However, N and P levels in T1 and T3 were lower than the commercial compost and appear to have altered biomass allocation patterns in both species relative to the commercial compost. The results suggest that there is potential to use invasive alien plant biowaste to improve soil for agricultural purposes.