Connectivity through allochthony: Reciprocal links between adjacent aquatic and terrestrial ecosystems in South Africa
- Richoux, Nicole B, Moyo, Sydney, Chari, Lenin D, Bergamino, Leandro, Carassou, Laure, Dalu, Tatenda, Hean, Jeffrey W, Sikutshwa, Likho, Gininda, Simphiwe, Magoro, Mandla L, Perhar, Gurbir, Ni, Felicity, Villet, Martin H, Whitfield, Alan K, Parker, Daniel M, Froneman, P William, Arhonditsis, George, Craig, Adrian J F K
- Authors: Richoux, Nicole B , Moyo, Sydney , Chari, Lenin D , Bergamino, Leandro , Carassou, Laure , Dalu, Tatenda , Hean, Jeffrey W , Sikutshwa, Likho , Gininda, Simphiwe , Magoro, Mandla L , Perhar, Gurbir , Ni, Felicity , Villet, Martin H , Whitfield, Alan K , Parker, Daniel M , Froneman, P William , Arhonditsis, George , Craig, Adrian J F K
- Date: 2015
- Subjects: To be catalogued
- Language: English
- Type: text , report
- Identifier: http://hdl.handle.net/10962/438363 , vital:73454 , ISBN 978-1-4312-0679-7 , https://wrcwebsite.azurewebsites.net/wp-content/uploads/mdocs/2186-1-15.pdf
- Description: An important aspect of the dynamics of nutrients and pollutants in natural systems is captured in the concept of allochthony, founded on the observation that nutrients and energy in a variety of forms are transferred between adjacent habitats, com-munities and ecosystems that are not routinely considered as connected. Different forms of nutrients and energy move across the conceptual boundaries of habitats via organisms’ activities or physical processes such as wind or water currents, and these transfers can represent important food subsidies. Such cross-partition ecolog-ical subsidies can augment the nutritional condition, biomass and biodiversity of communities, particularly where local production (or autochthony) alone may be inadequate to support local food webs. Furthermore, organic subsidies can influ-ence population dynamics, community interactions and ecosystem processes, and can represent dominant flux inputs in ecosystem budgets. Our intention was to ex-plore organic nutrient fluxes in relation to a primarily lotic (i.e. flowing) aquatic sys-tem at the scale of a hydrological catchment.
- Full Text:
- Date Issued: 2015
- Authors: Richoux, Nicole B , Moyo, Sydney , Chari, Lenin D , Bergamino, Leandro , Carassou, Laure , Dalu, Tatenda , Hean, Jeffrey W , Sikutshwa, Likho , Gininda, Simphiwe , Magoro, Mandla L , Perhar, Gurbir , Ni, Felicity , Villet, Martin H , Whitfield, Alan K , Parker, Daniel M , Froneman, P William , Arhonditsis, George , Craig, Adrian J F K
- Date: 2015
- Subjects: To be catalogued
- Language: English
- Type: text , report
- Identifier: http://hdl.handle.net/10962/438363 , vital:73454 , ISBN 978-1-4312-0679-7 , https://wrcwebsite.azurewebsites.net/wp-content/uploads/mdocs/2186-1-15.pdf
- Description: An important aspect of the dynamics of nutrients and pollutants in natural systems is captured in the concept of allochthony, founded on the observation that nutrients and energy in a variety of forms are transferred between adjacent habitats, com-munities and ecosystems that are not routinely considered as connected. Different forms of nutrients and energy move across the conceptual boundaries of habitats via organisms’ activities or physical processes such as wind or water currents, and these transfers can represent important food subsidies. Such cross-partition ecolog-ical subsidies can augment the nutritional condition, biomass and biodiversity of communities, particularly where local production (or autochthony) alone may be inadequate to support local food webs. Furthermore, organic subsidies can influ-ence population dynamics, community interactions and ecosystem processes, and can represent dominant flux inputs in ecosystem budgets. Our intention was to ex-plore organic nutrient fluxes in relation to a primarily lotic (i.e. flowing) aquatic sys-tem at the scale of a hydrological catchment.
- Full Text:
- Date Issued: 2015
Sexing adult pale-winged starlings using morphometric and discriminant function analysis
- Henry, Laurence, Biquand, Véroniquee, Craig, Adrian J F K, Hausberger, Martine
- Authors: Henry, Laurence , Biquand, Véroniquee , Craig, Adrian J F K , Hausberger, Martine
- Date: 2015
- Subjects: To be catalogued
- Language: English
- Type: article
- Identifier: http://hdl.handle.net/10962/465458 , vital:76611 , https://doi.org/10.1371/journal.pone.0135628
- Description: Accurate sexing of birds is vital for behavioral studies but can be a real problem in the field, especially for monomorphic species. Our goal here was to characterize the morphology of male and female monomorphic pale-winged starlings (Onychognathus nabouroup), a South African sturnid whose plumage is sexually monomorphic. Morphological measurements of genetically sexed animals indicated that males were statistically larger than females for five measurements: Mass, tail length, tarsus length and wing length. By using a Discriminant Function Analysis based on the measurements taken by one ringer, we were able to predict correctly the sex of 81.10% of the birds of data collected in the field and 77.9% of museum skins independently of year of capture and ringer. The model developed here should be useful for further field studies of this species.
- Full Text:
- Date Issued: 2015
- Authors: Henry, Laurence , Biquand, Véroniquee , Craig, Adrian J F K , Hausberger, Martine
- Date: 2015
- Subjects: To be catalogued
- Language: English
- Type: article
- Identifier: http://hdl.handle.net/10962/465458 , vital:76611 , https://doi.org/10.1371/journal.pone.0135628
- Description: Accurate sexing of birds is vital for behavioral studies but can be a real problem in the field, especially for monomorphic species. Our goal here was to characterize the morphology of male and female monomorphic pale-winged starlings (Onychognathus nabouroup), a South African sturnid whose plumage is sexually monomorphic. Morphological measurements of genetically sexed animals indicated that males were statistically larger than females for five measurements: Mass, tail length, tarsus length and wing length. By using a Discriminant Function Analysis based on the measurements taken by one ringer, we were able to predict correctly the sex of 81.10% of the birds of data collected in the field and 77.9% of museum skins independently of year of capture and ringer. The model developed here should be useful for further field studies of this species.
- Full Text:
- Date Issued: 2015
The importance of winter-flowering Aloe ferox for specialist and generalist nectar-feeding birds
- Kuiper, Timothy R, Smith, Diane L, Wolmarans, Milena H L, Jones, Sara S, Forbes, Ross W, Hulley, Patrick E, Craig, Adrian J F K
- Authors: Kuiper, Timothy R , Smith, Diane L , Wolmarans, Milena H L , Jones, Sara S , Forbes, Ross W , Hulley, Patrick E , Craig, Adrian J F K
- Date: 2015
- Subjects: To be catalogued
- Language: English
- Type: article
- Identifier: http://hdl.handle.net/10962/465538 , vital:76618 , https://doi.org/10.1071/MU14054
- Description: The abundance of consumers and the availability of resources are often linked, and birds are known to track food resources at a variety of spatial and temporal scales. This study describes the seasonal influx of nectar-feeding birds during flowering in a 51-ha stand of Aloe ferox in the Eastern Cape, South Africa, over 5 years (2008–09 and 2011–13). Bimonthly point counts of birds were conducted before (April—May), during (June—July) and after (August) flowering, which occurs during the austral winter. The abundance of nectar-feeding birds increased significantly during flowering each year, whereas monthly abundances of non-nectarivores were unrelated to flowering. Models fitted to bird count-data revealed a significant interaction between feeding guild (nectarivorous versus non-nectarivorous species) and the percentage of flowering A. ferox over the 5 years of the study, confirming that these guilds responded differently to flowering events. Malachite Sunbirds (Nectarina famosa), which are specialist nectarivores, responded consistently to flowering of A. ferox each year, despite the low sugar concentrations of A. ferox nectar. The arrival of nectar-feeding birds en masse during flowering, and the number of bird species (16) observed feeding on A. ferox nectar, suggest that this plant is an important source of nutrition for birds at a time when other food resources are likely to be scarce.
- Full Text:
- Date Issued: 2015
- Authors: Kuiper, Timothy R , Smith, Diane L , Wolmarans, Milena H L , Jones, Sara S , Forbes, Ross W , Hulley, Patrick E , Craig, Adrian J F K
- Date: 2015
- Subjects: To be catalogued
- Language: English
- Type: article
- Identifier: http://hdl.handle.net/10962/465538 , vital:76618 , https://doi.org/10.1071/MU14054
- Description: The abundance of consumers and the availability of resources are often linked, and birds are known to track food resources at a variety of spatial and temporal scales. This study describes the seasonal influx of nectar-feeding birds during flowering in a 51-ha stand of Aloe ferox in the Eastern Cape, South Africa, over 5 years (2008–09 and 2011–13). Bimonthly point counts of birds were conducted before (April—May), during (June—July) and after (August) flowering, which occurs during the austral winter. The abundance of nectar-feeding birds increased significantly during flowering each year, whereas monthly abundances of non-nectarivores were unrelated to flowering. Models fitted to bird count-data revealed a significant interaction between feeding guild (nectarivorous versus non-nectarivorous species) and the percentage of flowering A. ferox over the 5 years of the study, confirming that these guilds responded differently to flowering events. Malachite Sunbirds (Nectarina famosa), which are specialist nectarivores, responded consistently to flowering of A. ferox each year, despite the low sugar concentrations of A. ferox nectar. The arrival of nectar-feeding birds en masse during flowering, and the number of bird species (16) observed feeding on A. ferox nectar, suggest that this plant is an important source of nutrition for birds at a time when other food resources are likely to be scarce.
- Full Text:
- Date Issued: 2015
The timing of moult in males and females of the monomorphic Pale-winged Starling Onychognathus nabouroup
- Craig, Adrian J F K, Bonnevie, Bo T, Hausberger, Martine, Henry, Laurence
- Authors: Craig, Adrian J F K , Bonnevie, Bo T , Hausberger, Martine , Henry, Laurence
- Date: 2015
- Subjects: To be catalogued
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/443805 , vital:74155 , https://hdl.handle.net/10520/EJC177689
- Description: Pale-winged Starlings Onychognathus nabouroup inhabit the arid western interior of southern Africa and moult-breeding overlap may occur. We collected field data in two successive years on the moult of individual birds, whose sex was confirmed by genetic techniques. Small samples revealed a non-significant tendency for the moult of females in the early stages of wing moult to be more advanced than that of males in both years, but also clear evidence that the starting date of moult differed in the two years. In this species the moult schedule may thus be variable at both the individual and the population levels.
- Full Text:
- Date Issued: 2015
- Authors: Craig, Adrian J F K , Bonnevie, Bo T , Hausberger, Martine , Henry, Laurence
- Date: 2015
- Subjects: To be catalogued
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/443805 , vital:74155 , https://hdl.handle.net/10520/EJC177689
- Description: Pale-winged Starlings Onychognathus nabouroup inhabit the arid western interior of southern Africa and moult-breeding overlap may occur. We collected field data in two successive years on the moult of individual birds, whose sex was confirmed by genetic techniques. Small samples revealed a non-significant tendency for the moult of females in the early stages of wing moult to be more advanced than that of males in both years, but also clear evidence that the starting date of moult differed in the two years. In this species the moult schedule may thus be variable at both the individual and the population levels.
- Full Text:
- Date Issued: 2015
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