Spider ecology in the Erfenis Dam Nature Reserve, Free State Province: (Arachnida: Araneae)
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Date
2010-01
Authors
Fourie, Rene
Journal Title
Journal ISSN
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Publisher
University of the Free State
Abstract
English: Few spider studies have been done in the Grassland Biome of South Africa, even though it dominates the central part of South Africa. In September 2005, a study was initiated in Erfenis Dam Nature Reserve, Free State Province, to determine the impact of controlled burning on various faunal groups. Thus, the aim of this study was to determine the effect of controlled burning on ground-dwelling spider communities in the reserve. Pitfall traps were set out in six different sites in the reserve, with three sites located in the burned area and the other three sites in the unburned area. The traps were replaced every 30 days for one year between 21 September 2005 (day following burning) and 30 September 2006. During this period, a total of 5222 spiders representing 33 families and 121 species were collected. In the burned sites Gnaphosidae, Lycosidae, Caponiidae and Salticidae, were dominant in abundance, while Gnaphosidae, Lycosidae, Amaurobiidae and Corinnidae were dominant in the unburned sites. Monthly spider abundance and species richness were consistently lower in the burned grassland, suggesting that succession and colonisation processes are slow. Gnaphosidae and Lycosidae were present throughout the year in all six sites, indicating that they are either fire tolerant or fast colonisers.
The potential was recognised to expand the study to the sampling of grass- and foliage-dwelling spiders as well. This study was conducted from November 2005 until August 2007, with sampling done in the last week of every third month. Foliage spiders were collected from three different tree species (Acacia karroo, Rhus lancea and Rhus ciliata) by beating. During the period of two years a total of 496 foliage spiders were collected that represented 17 families and 54 species. Sweeps were done in four different grasslands (uniform Themeda triandra, mixed, weedy and woodland grasslands). During the period of two years a total of 1649 spiders were collected that represented 15 families and 84 species. The families that dominate the Grassland biome in abundance are the Araneidae, Philodromidae, Salticidae and Thomisidae, due mainly because of the vegetation structure and complexity. More spider species as well as individuals were collected from the grasslands than from the tree layers, but the tree layers had a greater diversity of spider families.
As part of the ground-dwelling spider study, the influence of termite activity on the activity of Ammoxenus amphalodes Dippenaar & Meyer (Ammoxenidae) was determined. A. amphalodes activity were concentrated in the two sites that had the greatest termite activity, especially that of Hodotermes mossambicus Hagen. Both A. amphalodes and H. mossambicus abundance were significantly influenced by soil type, which affects nest construction in H. mossambicus and foraging behaviour in A. amphalodes.
While sorting the traps for the study on ground-dwelling spiders, a species of Calommata (Atypidae) known as the African purse-web spider was found. In South Africa the genus was last collected in the 1920’s, when specimens were collected from several localities in Gauteng and the Soutpansberg. Subsequently, no material was collected until the recent discovery of a species in Groenkloof Nature Reserve in Gauteng in 2001, a male in the Blouberg Nature Reserve (Limpopo Province) and eight males found in pitfall traps in Erfenis Dam Nature Reserve. All of the material had previously been regarded as Calommata simoni Pocock, but examination of all available material indicated that at least six species occurred in the Afrotropical Region, four of which are described as new. Calommata transvaalica Hewitt is removed from synonymy with C. simoni and revalidated. C. meridionalis sp. n. showed a preference for soils with relative high clay content. Males of this species also showed most activity from October to November.
Afrikaans: Min studies oor spinnekoppe is al gedoen in die Grasland Bioom van Suid-Afrika, al domineer dit die sentrale gedeelte. In September 2005 is ’n studie begin te Erfenis Dam Natuur Reservaat, Vrystaat Provinsie, om die invloed van beheerde brande op verskeie fauna groepe te bepaal. Die doel van hierdie studie was om die effek van beheerde brande op grondlewende spinnekop gemeenskappe te bepaal in die reservaat. Pitvalle is uitgesit in ses verskillende lokaliteite in die reservaat, met drie lokaliteite wat geplaas was in die gebrande area en die ander drie in die ongebrande area. Die valle is elke 30 dae vervang vir een jaar tussen 21 September 2005 (dag na brand) en 30 September 2006. Gedurende hierdie tydperk is ‘n totaal van 5222 spinnekoppe, wat 33 families en 121 spesies verteenwoordig, versamel. In die gebrande areas was Gnaphosidae, Lycosidae, Caponiidae en Salticidae dominant, terwyl Gnaphosidae, Lycosidae, Amaurobiidae en Corinnidae dominant was in die ongebrande areas. Maandlikse spinnekop getalle en spesie rykheid was voortdurend laer in die gebrande grasland, wat voorstel dat suksessie en kolonisasie prosesse stadig is. Gnaphosidae en Lycosidae was regdeur die jaar teenwoordig in al ses lokaliteite, wat aandui dat hulle, of vuur tolerant, of vinnige koloniseerders is. Potensiaal is raakgesien om die studie te verbreed deur gras- en plantlewende spinnekoppe ook te versamel. Dié studie is gedoen vanaf November 2005 tot Augustus 2007, met opnames wat gedoen is in die laaste week van elke derde maand. Plantlewende spinnekoppe is versamel vanaf drie verskillende boom spesies (Acacia karroo, Rhus lancea en Rhus ciliata). In die tydperk is ’n totaal van 496 plantlewende spinnekoppe, wat 17 families en 54 spesies verteenwoordig, versamel. Veenetversameling is uitgevoer in vier verskillende grasvelde (eenvormige Themeda triandra, gemengde, onkruid en woudland graslande). ‘n Totaal van 1649 spinnekoppe, wat 15 families en 84 spesies verteenwoordig, is versamel. Die tipe plant strukture en kompleksiteit het die families; Araneidae, Philodromidae, Salticidae en Thomisidae, wat die Grasland bioom gedomineer het bepaal. Meer spinnekop spesies sowel as individue is versamel vanuit die graslande as van bome, maar die bome het ’n groter diversiteit van spinnekop families gehad. As ‘n deel van die grondlewende spinnekop studie, is bepaal die invloed van termiet aktiwiteit is op die aktiwiteit van Ammoxenus amphalodes Dippenaar & Meyer (Ammoxenidae). A. amphalodes aktiwiteit is gekonsentreer in die twee areas met die grootste termiet aktiwiteit, veral dié van Hodotermes mossambicus Hagen. Beide A. amphalodes en H. mossambicus volopheid is grootliks beïnvloed deur grondtipe, wat nes konstruksie affekteer in H. mossambicus en voedings gedrag in A. amphalodes. Met die pitval sortering vir die grondlewende spinnekop studie, is ‘n spesie van Calommata (Atypidae), ook bekend as die Afrika beurs-web spinnekop, gevind. In Suid-Afrika is die genus laas versamel in die 1920’s, toe eksemplare in verskeie lokaliteite in Gauteng en die Soutpansberge versamel was. Sedertdien is geen materiaal weer versamel nie tot die onlangse ontdekking van ’n spesie in die Groenkloof Natuur Reservaat in Gauteng in 2001, ’n mannetjie in die Blouberg Natuur Reservaat (Limpopo Provinsie) en die agt mannetjies wat versamel is in die pitvalle te Erfenis Dam Natuur Reservaat. Alle vorige materiaal was voorheen bekend as Calommata simoni Pocock, totdat alle beskikbare materiaal van nader ondersoek is en dit gevind is dat daar ten minste ses spesies in die Afrotropiese Streek voorkom. Vier hiervan word hier as nuwe spesies beskryf. Calommata transvaalica Hewitt is verwyder van sinonimie met C. simoni en word weer herken. C. meridionalis sp. n. het ‘n voorkeur vir grond met relatiewe hoë klei inhoud en mannetjies van hierdie spesie was meestal aktief vanaf Oktober tot November.
Afrikaans: Min studies oor spinnekoppe is al gedoen in die Grasland Bioom van Suid-Afrika, al domineer dit die sentrale gedeelte. In September 2005 is ’n studie begin te Erfenis Dam Natuur Reservaat, Vrystaat Provinsie, om die invloed van beheerde brande op verskeie fauna groepe te bepaal. Die doel van hierdie studie was om die effek van beheerde brande op grondlewende spinnekop gemeenskappe te bepaal in die reservaat. Pitvalle is uitgesit in ses verskillende lokaliteite in die reservaat, met drie lokaliteite wat geplaas was in die gebrande area en die ander drie in die ongebrande area. Die valle is elke 30 dae vervang vir een jaar tussen 21 September 2005 (dag na brand) en 30 September 2006. Gedurende hierdie tydperk is ‘n totaal van 5222 spinnekoppe, wat 33 families en 121 spesies verteenwoordig, versamel. In die gebrande areas was Gnaphosidae, Lycosidae, Caponiidae en Salticidae dominant, terwyl Gnaphosidae, Lycosidae, Amaurobiidae en Corinnidae dominant was in die ongebrande areas. Maandlikse spinnekop getalle en spesie rykheid was voortdurend laer in die gebrande grasland, wat voorstel dat suksessie en kolonisasie prosesse stadig is. Gnaphosidae en Lycosidae was regdeur die jaar teenwoordig in al ses lokaliteite, wat aandui dat hulle, of vuur tolerant, of vinnige koloniseerders is. Potensiaal is raakgesien om die studie te verbreed deur gras- en plantlewende spinnekoppe ook te versamel. Dié studie is gedoen vanaf November 2005 tot Augustus 2007, met opnames wat gedoen is in die laaste week van elke derde maand. Plantlewende spinnekoppe is versamel vanaf drie verskillende boom spesies (Acacia karroo, Rhus lancea en Rhus ciliata). In die tydperk is ’n totaal van 496 plantlewende spinnekoppe, wat 17 families en 54 spesies verteenwoordig, versamel. Veenetversameling is uitgevoer in vier verskillende grasvelde (eenvormige Themeda triandra, gemengde, onkruid en woudland graslande). ‘n Totaal van 1649 spinnekoppe, wat 15 families en 84 spesies verteenwoordig, is versamel. Die tipe plant strukture en kompleksiteit het die families; Araneidae, Philodromidae, Salticidae en Thomisidae, wat die Grasland bioom gedomineer het bepaal. Meer spinnekop spesies sowel as individue is versamel vanuit die graslande as van bome, maar die bome het ’n groter diversiteit van spinnekop families gehad. As ‘n deel van die grondlewende spinnekop studie, is bepaal die invloed van termiet aktiwiteit is op die aktiwiteit van Ammoxenus amphalodes Dippenaar & Meyer (Ammoxenidae). A. amphalodes aktiwiteit is gekonsentreer in die twee areas met die grootste termiet aktiwiteit, veral dié van Hodotermes mossambicus Hagen. Beide A. amphalodes en H. mossambicus volopheid is grootliks beïnvloed deur grondtipe, wat nes konstruksie affekteer in H. mossambicus en voedings gedrag in A. amphalodes. Met die pitval sortering vir die grondlewende spinnekop studie, is ‘n spesie van Calommata (Atypidae), ook bekend as die Afrika beurs-web spinnekop, gevind. In Suid-Afrika is die genus laas versamel in die 1920’s, toe eksemplare in verskeie lokaliteite in Gauteng en die Soutpansberge versamel was. Sedertdien is geen materiaal weer versamel nie tot die onlangse ontdekking van ’n spesie in die Groenkloof Natuur Reservaat in Gauteng in 2001, ’n mannetjie in die Blouberg Natuur Reservaat (Limpopo Provinsie) en die agt mannetjies wat versamel is in die pitvalle te Erfenis Dam Natuur Reservaat. Alle vorige materiaal was voorheen bekend as Calommata simoni Pocock, totdat alle beskikbare materiaal van nader ondersoek is en dit gevind is dat daar ten minste ses spesies in die Afrotropiese Streek voorkom. Vier hiervan word hier as nuwe spesies beskryf. Calommata transvaalica Hewitt is verwyder van sinonimie met C. simoni en word weer herken. C. meridionalis sp. n. het ‘n voorkeur vir grond met relatiewe hoë klei inhoud en mannetjies van hierdie spesie was meestal aktief vanaf Oktober tot November.
Description
Keywords
Grassland Biome, Burning, Tree species, Grasslands, Ammoxenus amphalodes, Calommata spp., Taxonomy, Arachnida -- South Africa -- Free State, Insects -- Ecology -- South Africa -- Free State, Dissertation (M.Sc. (Zoology and Entomology))--University of the Free State, 2010