Fatty acid analyses provide novel insights on hippo defecation and consequences for aquatic food webs
- Authors: Dawson, Jessica , Pillay, Deena , Perissinotto, Renzo , Richoux, Nicole B
- Date: 2020
- Subjects: To be catalogued
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/454346 , vital:75337 , xlink:href="https://doi.org/10.1038/s41598-020-68369-5"
- Description: By defecating grasses into aquatic systems at massive scales and intensities, hippos can initiate complex changes to aquatic ecosystems. However, consequent effects on food webs are not well understood, particularly regarding shifts in basal resource contributions to consumer diets and their physiological condition. Here, we use fatty acid analysis to show that dense hippo aggregations and high dung loading are associated with (1) alterations to basal resource pools, (2) reduced quality of sediment organic matter and (3) increases in terrestrial and bacterial biomarker levels, but declines in those of diatoms in estuarine secondary consumers. While hippo defecation can increase boundary permeability between terrestrial and aquatic systems, our findings indicate that this may lead to a shift from a microphytobenthic food web base to one with increasing bacterial contributions to higher consumers. Our findings expand understanding of the mechanisms by which an iconic African megaherbivore indirectly structures aquatic ecosystems.
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- Date Issued: 2020
Modern supratidal microbialites fed by groundwater: functional drivers, value and trajectories
- Authors: Rishworth, Gavin M , Dodd, Carla , Perissinotto, Renzo , Bornman, Thomas G , Adams, Janine B , Anderson, Callum R , Cawthra, Hayley C , Dorrington, Hayley C , du Toit, Hendrik , Edworthy, Carla , Gibb, Ross-Lynne A , Human, Lucienne R D , Isemonger, Eric W , Lemley, David A , Miranda, Nelson A , Peer, Nasreen , Raw, Jacqueline L , Smith, Alan M , Steyn, Paul-Pierre , Strydom, Nadine A , Teske, Peter R , Welman, Peter R
- Date: 2020
- Subjects: To be catalogued
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/426008 , vital:72306 , xlink:href="https://doi.org/10.1016/j.earscirev.2020.103364"
- Description: Microbial mats were the dominant habitat type in shallow marine environments between the Palaeoarchean and Phanerozoic. Many of these (termed ‘microbialites’) calcified as they grew but such lithified mats are rare along modern coasts for reasons such as unsuitable water chemistry, destructive metazoan influences and competition with other reef-builders such as corals or macroalgae. Nonetheless, extant microbialites occur in unique coastal ecosystems such as the Exuma Cays, Bahamas or Lake Clifton and Hamelin Pool, Australia, where limitations such as calcium carbonate availability or destructive bioturbation are diminished. Along the coast of South Africa, extensive distributions of living microbialites (including layered stromatolites) have been discovered and described since the early 2000s. Unlike the Bahamian and Australian ecosystems, the South African microbialites form exclusively in the supratidal coastal zone at the convergence of emergent groundwater seepage. Similar systems were documented subsequently in southwestern Australia, Northern Ireland and the Scottish Hebrides, as recently as 2018, revealing that supratidal microbialites have a global distribution. This review uses the best-studied formations to contextualise formative drivers and processes of these supratidal ecosystems and highlight their geological, ecological and societal relevance.
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- Date Issued: 2020
Tufa stromatolite ecosystems on the South African south coast
- Authors: Perissinotto, Renzo , Bornman, Tommy G , Steyn, Paul-Pierre , Miranda, Nelson A F , Dorrington, Rosemary A , Matcher, Gwynneth F , Strydom, Nadine A , Peer, Nasreen
- Date: 2014
- Language: English
- Type: Article
- Identifier: vital:6490 , http://hdl.handle.net/10962/d1014585 , http://dx.doi.org/10.1590/sajs.2014/20140011
- Description: Following the first description of living marine stromatolites along the South African east coast, new investigations along the south coast have revealed the occurrence of extensive fields of actively calcifying stromatolites. These stromatolites have been recorded at regular distances along a 200-km stretch of coastline, from Cape Recife in the east to the Storms River mouth in the west, with the highest density found between Schoenmakerskop and the Maitland River mouth. All active stromatolites are associated with freshwater seepage streams flowing from the dune cordon, which form rimstone dams and other accretions capable of retaining water in the supratidal platform. Resulting pools can reach a maximum depth of about 1 m and constitute a unique ecosystem in which freshwater and marine organisms alternate their dominance in response to vertical mixing and the balance between freshwater versus marine inflow. Although the factors controlling stromatolite growth are yet to be determined, nitrogen appears to be supplied mainly via the dune seeps. The epibenthic algal community within stromatolite pools is generally co-dominated by cyanobacteria and chlorophytes, with minimal diatom contribution.
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- Date Issued: 2014
Eudicella trimeni Janson, 1884 (Coleoptera: Scarabaeidae: Cetoniinae: Goliathini): Description of larva with notes on conservation status, biology and taxonomy
- Authors: Perissinotto, Renzo , Orozco, Jesús (Entomologist)
- Date: 2013
- Subjects: Afrotropical , Goliathini , Eudicella trimeni , Scarab beetles , Fruit chafers , Flower chafers , Larva , Grubs , Rosenkäfer
- Language: English
- Type: Article
- Identifier: vital:6559 , http://hdl.handle.net/10962/d1006605 , http://africaninvertebrates.org/ojs/index.php/AI/article/view/307
- Description: Eudicella trimeni is reportedly one of the most endangered species of the genus, having been declared virtually extinct until recently. Present research has shown that the species occurs in an area wider than previously known. However, its habitat is disappearing at a fast rate and the Eastern Cape and KwaZulu-Natal populations appear to be sufficiently different from each other to warrant at least subspecies status and further investigation. Third instar larvae of the northern population were collected recently in the Karkloof Nature Reserve, KwaZulu-Natal. They were reared to adulthood under environmentally controlled conditions and are here described.
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- Date Issued: 2013
Revision of the genus Xiphoscelis Burmeister 1842 (Coleoptera Scarabaeidae Cetoniinae), with description of two new species and notes on its phylogeny and ecology
- Authors: Perissinotto, Renzo , Villet, Martin H , Stobbia, P
- Date: 2003
- Subjects: To be catalogued
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/442293 , vital:73973 , https://doi.org/10.1080/03946975.2003.10531184
- Description: Recent field work has shown that the genus Xiphoscelis Burmeister 1842 contains at least three species. The type species is re-described, and two new species are described, based on adult morphology. The distribution of all three Xiphoscelis species is mapped, and a phylogeny is proposed for the genus. Ecological data are presented and discussed in the context of the previously-reported association of members of this genus with termites.
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- Date Issued: 2003
Description of adult and larva of Ichnestoma pringlei n. sp. (Coleoptera: Scarabaeidae Cetoniinae), with notes on its biology and ecology
- Authors: Perissinotto, Renzo , Smith, Tamara J , Stobbia, P
- Date: 1999
- Subjects: To be catalogued
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/453815 , vital:75289 , https://doi.org/10.1080/03946975.1999.10539390
- Description: There are at present 10 described species in the primitive genus Ichnestoma Gory and Percheron 1833. These are all phylogenetic and geographic relicts of high evolutionary and conservation interest. The discovery of a new species, I. pringlei n. sp., and the first description of a larva (third instar) of this genus are reported here. New information is also presented on their life-cycle and on the dependence of their activities on rainfall patterns, particularly in the semi-arid region of the Karoo. In this region, larvae seem to take 2 years to complete growth and metamorphosis since they feed only after major rainfall events, while remaining inactive and deep underground during dry periods. Adults emerge from their cocoons only after summer rains of at least 15 mm. They lack functional mouth parts and are unable to feed. Their life span is only 3–5 days. Because females are completely flightless and unable to disperse, species of the genus are extremely vulnerable to environmental degradation. It seems likely that they may play a key role in the decomposition of dead plant matter, especially in dry and clay-rich soils where other primary decomposers are scarce.
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- Date Issued: 1999
The larva of Rhinocoeta sanguinipes (Gory and Percheron 1833) (Coleoptera Scarabaeidae) description and phylogenetic inferences
- Authors: Smith, Tamara J , Perissinotto, Renzo , Villet, Martin H
- Date: 1998
- Subjects: To be catalogued
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/453942 , vital:75299 , https://doi.org/10.1080/03946975.1998.10539365
- Description: The genus Rhinocoeta Burmeister 1842 is unusual among cetoniines, as adults do not feed on flowers or fruits. The biology and ecology of the genus are still completely unknown, and only for three of the six species representing the group have adults of both sexes been described. No information is available for the larval stages of any of the species. Here, we present the first discription of the third instar larvae of one of the species, Rhinocoeta sanguinipes (Gory and Percheron 1833). Cladistic analysis of larval characters confirms the primitive phylogenetic position of this species relative to a small sample of other South African cetoniines, and supports the hypothesis that the genus might belong in the subtribe Xiphoscelidina rather than the Cetoniina, thereby constituting part of a relict lineage derived directly from the most primitive Cetoniinae.
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- Date Issued: 1998
South African estuaries in the Anthropocene
- Authors: Perissinotto, Renzo
- Subjects: Estuaries -- South Africa , Geology, Stratigraphic -- Anthropocene , f-sa
- Language: English
- Type: text , Lectures
- Identifier: http://hdl.handle.net/10948/20977 , vital:29424
- Description: In the new geological epoch of total human dominance of the planet, already widely referred to as the “Anthropocene”, estuaries are among the most vulnerable ecosystems to the changes that man’s activities have imposed on the coastal zone. For the non-specialist, an estuary is a “semi-enclosed coastal body of water, which has a permanent or temporary connection with the open sea, and within which sea water is diluted with fresh water from land drainage”.
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