Bio: Amy-Leigh Wilson is an academic researcher from University of KwaZulu-Natal. The author has contributed to research in topics: Frugivore & Tauraco corythaix. The author has an hindex of 9, co-authored 23 publications receiving 223 citations.
TL;DR: Nutritional composition was investigated in various indigenous fruit species that avian frugivores feed on in KwaZulu-Natal Afromontane and coastal forests to provide an understanding of the inter-relationships between indigenous fruit and frugovores in South Africa.
TL;DR: Small populations of A. pruinosa are viable in terms of pollination processes and should be protected from more direct threats, such as habitat alteration.
Abstract: Small populations of many plant species have been shown to exhibit ecological Allee effects. These effects are expected to be pronounced in plants which are obligate outcrossers and rely on pollinators which forage preferentially in larger populations with greater nectar availability. We examined the breeding and pollination systems, level of pollen limitation and seed production in populations of a threatened “ornithophilous” species, Aloe pruinosa. Experimental hand-pollinations showed that A. pruinosa is genetically self-incompatible and thus an obligate outcrosser. Experimental exclusion of birds from inflorescences did not affect seed production, suggesting that insects are effective pollinators. Supplemental hand-pollinations in several populations showed that seed production in A. pruinosa is not pollen limited. Further, there were no significant relationships between population size and any measure of reproductive success in this Aloe species. Small populations of A. pruinosa are thus viable in terms of pollination processes and should be protected from more direct threats, such as habitat alteration.
TL;DR: The results suggest that Knysna and purple-crested turacos are legitimate seed dispersers of fleshy-fruited invasive plants, while rose-ringed parakeets are mainly seed predators.
Abstract: Avian frugivores play a key role in seed dispersal of many plant species, including invasive alien plants. We assessed the effect of gut passage on the germination of selected invasive alien plant species in South Africa. Fruits of four fleshly-fruited invasive alien plant species: Solanum mauritianum, Cinnamomum camphora, Psidium guajava, and Morus alba, were fed to two species of indigenous turacos, Knysna (Tauraco corythaix) and purple-crested (Gallirex porphyreolophus) turacos, and to invasive rose-ringed parakeets (Psittacula krameri). Seed retention time was determined as this can influence both seed dispersal and germination success. Germination success of ingested seeds was compared with that of manually de-pulped seeds, as well as to seeds in whole fruit. The germination success of seeds of all the invasive plant species increased significantly after ingestion by both turaco species compared with seeds from whole fruits. Germination success of manually de-pulped seeds did not differ significantly from that of turaco ingested seeds. In contrast, seed passage through the digestive tract of rose-ringed parakeets significantly reduced germination success and viability of ingested invasive plant species. Our results suggest that Knysna and purple-crested turacos are legitimate seed dispersers of fleshy-fruited invasive plants, while rose-ringed parakeets are mainly seed predators. Although seed predation by rose-ringed parakeets negatively affects the reproductive success of these plants, it is unlikely that this will suppress the spread of these invasive alien plants in South Africa as they are already well established. Furthermore, they can facilitate dispersal by seed regurgitation and dropping uneaten fruits away from the parent plant. Similar trends could be expected for indigenous seeds that rose-ringed parakeets feed on and therefore these birds remain a negative influence within invaded ecosystems.
TL;DR: Seed ingestion by Knysna Turacos did not influence the rate at which seeds germinated in 83% of the tree species, but ingested Ficus lutea and Ficus natalensis seeds germine significantly sooner than whole fruit seeds.
TL;DR: The results suggest that Knysna Turacos show seasonal thermoregulatory responses that represent cold defense rather than energy conservation, which is contrary to what was expected.
TL;DR: This study test the climatic variability hypothesis for endotherms, with a comprehensive dataset on thermal tolerances derived from physiological experiments, and uses these data to assess the vulnerability of species to projected climate change.
Abstract: The relationships among species' physiological capacities and the geographical variation of ambient climate are of key importance to understanding the distribution of life on the Earth. Furthermore, predictions of how species will respond to climate change will profit from the explicit consideration of their physiological tolerances. The climatic variability hypothesis, which predicts that climatic tolerances are broader in more variable climates, provides an analytical framework for studying these relationships between physiology and biogeography. However, direct empirical support for the hypothesis is mostly lacking for endotherms, and few studies have tried to integrate physiological data into assessments of species' climatic vulnerability at the global scale. Here, we test the climatic variability hypothesis for endotherms, with a comprehensive dataset on thermal tolerances derived from physiological experiments, and use these data to assess the vulnerability of species to projected climate change. We find the expected relationship between thermal tolerance and ambient climatic variability in birds, but not in mammals—a contrast possibly resulting from different adaptation strategies to ambient climate via behaviour, morphology or physiology. We show that currently most of the species are experiencing ambient temperatures well within their tolerance limits and that in the future many species may be able to tolerate projected temperature increases across significant proportions of their distributions. However, our findings also underline the high vulnerability of tropical regions to changes in temperature and other threats of anthropogenic global changes. Our study demonstrates that a better understanding of the interplay among species' physiology and the geography of climate change will advance assessments of species' vulnerability to climate change.
Bournemouth University1, Landcare Research2, University of Exeter3, The Lodge4, Ghent University5, University of Birmingham6, Met Office7, University of Melbourne8, University of Basel9, University of Picardie Jules Verne10, Natural England11, University of Otago12, University of York13, University of Cambridge14
TL;DR: In this paper, the authors provide an overview of microclimatic processes and summarise the available methods of measuring and modelling microclimate data for incorporation in ecological research, highlighting pitfalls to avoid emerging novel methods and the limitations of some techniques.
Abstract: Most ecological studies of the effects of climate on species are based on average conditions above ground level (measured by meteorological stations) averaged across 100 km2 or larger areas. However, most terrestrial organisms experience conditions in a much smaller area at the ground surface or within vegetation canopies, the climate of which can be very different to large-scale averages. Therefore, to accurately characterise the climatic conditions suitable for species, it is essential to include microclimate information. Microclimates are affected by the shape of the landscape, including the steepness and aspect of slopes, height above sea level, proximity to the sea or inland water, and whether a site is in a valley or at the top of a hill. Plants also modify the conditions found within or below their canopies, with the structure of vegetation playing an important role. The recent increase in the availability of microsensors and remotely sensed data at appropriate resolutions has led some ecologists to begin to include microclimate information within a variety of contexts; however the field can be confusing and intimidating and mistakes are often made along the way. In this chapter, we provide an overview of microclimatic processes and summarise the available methods of measuring and modelling microclimate data for incorporation in ecological research. We highlight pitfalls to avoid emerging novel methods and the limitations of some techniques. We also consider future research directions and opportunities within this emerging field.
TL;DR: Previous evidence for the importance of hornbills, bulbuls, elephants, gibbons, civets, and fruit bats in seed dispersal is reinforced, and it is suggested that the roles of green pigeons, macaques, rodents, bears, and deer were previously underestimated.
TL;DR: Data is reviewed that support the role of LAN as an endocrine disruptor in humans to be considered in treatments and lifestyle suggestions, and the potential for ecosystem-wide effects of artificial LAN is discussed.