72 research outputs found
Data for: Well-managed grassland heterogeneity promotes butterfly conservation in a corridor network
No full textThis file contains species data for butterflies and dominant plant assemblages, as well as environmental variables at each of the 37 sites
A taxonomic study of the genus cryptolepis (periplocoideae: apocynaceae)
No full textEnglish: Cryptolepis R.Br. (Apocynaceae, Periplocoideae) was taxonomically revised. Detailed descriptions of macro and micro-morphology, palynology, geographic distribution and ecological characteristics were presented. An identification key to the species was compiled and the nomenclature of all species was revised while all available type material was studied and lectotypes and neotypes were designated where necessary. Molecular phylogenetic analyses, based on the gene regions ITS, trnD–T and trnT–F, of representative species of 28 periplocoid genera and 22 Cryptolepis species were presented and the monophyly of Cryptolepis was evaluated.
Historically a total of 81 species names and four subspecies names were published for Cryptolepis. However, a large number of species names were later placed in synonymy or transferred to other genera, while several new combinations were published. This resulted in a total of 29 accepted Cryptolepis species at the commencement of this study. Three new species, C. ibayana, C. thulinii and C. villosa, resulted from this study and the latter two were described in this thesis. One species, C. producta, was synonymised with C. oblongifolia. Cryptolepis, therefore, comprises a total of 31 species at present.
In terms of species diversity, distribution and potential pharmaceutical and economic value, Cryptolepis is one of the most significant genera in the Periplocoideae. Cryptolepis grows throughout sub-Saharan Africa, the southern parts of Yemen, the island archipelago of Socotra, and southern Asia ranging from India to southern China, Taiwan, the Philippines and Indonesia. Most of the species grow in tropical forests or savannah, but 13 species are also adapted to arid environments.
The majority of Cryptolepis species are concentrated in four centres of diversity along the east coast of Africa and on Socotra. These hotspots are associated with both arid and forest refugia in areas which have been regarded as local centres of endemism for a number of other plant taxa. The phylogenetic analysis of Cryptolepis indicates that most of these hotspots were colonized repeatedly by different Cryptolepis groups. In addition to the influence of climate shifts, edaphic conditions and also fire had a significant influence on species diversity and distribution in Cryptolepis.
Macro and micro-morphological investigations indicated that numerous characters, including growth form, leaf shape and size, leaf epidermal characters, venation, inflorescence structure, floral structure and seed coat surface characters, are of diagnostic value at species level in Cryptolepis. However, the species can only be accurately identified by using a combination of these characters.
The molecular phylogenetic analyses revealed that Cryptolepis is paraphyletic and, in order to establish a monophyletic genus, it was proposed that the circumscription of the genus be broadened to include Parquetina as a synonym of Cryptolepis.
Several vegetative and reproductive characters showed a high degree of homoplasy, suggesting a high degree of morphological plasticity. This plasticity was also found at species level in C. oblongifolia, which showed significant variation in vegetative and reproductive features. This, together with a high tolerance for disturbance, has resulted in C. oblongifolia becoming the most widely distributed of all Cryptolepis species.Afrikaans: Cryptolepis R.Br. (Apocynaceae, Periplocoideae) is taksonomies hersien. Volledige beskrywings van die makro- en mikromorfologie, palinologie, geografiese verspreiding en ekologiese eienskappe is aangebied. 'n Uitkenningsleutel tot die spesies is opgestel, die nomenklatuur van al die spesies is hersien, terwyl alle beskikbare tipemateriaal bestudeer is en lekto- en neotipes is, waar nodig, aangewys. Molekulêre filogenetiese ontledings, gebaseer op die geenstreke ITS, trnD–T en trnT–F, van verteenwoordigende spesies van 28 periplokoide genusse en 22 Cryptolepis spesies is in die ondersoek ingesluit, en die monofilie van Cryptolepis is beoordeel.
Histories is 'n totaal van 81 spesies en vier subspesies name vir Cryptolepis gepubliseer. 'n Groot aantal van hierdie spesiesname is egter later in sinonomie geplaas of na ander genusse oorgeplaas, terwyl 'n aantal nuwe kombinasies gepubliseer is. Met die aanvang van die huidige studie was daar dus 'n totaal van 29 erkende spesies in Cryptolepis. 'n Verdere drie nuwe spesies, C. ibayana, C. thulinii en C. villosa, is die resultaat van hierdie studie, waarvan die laasgenoemde twee in hierdie proefskrif beskryf is. Een spesie, C. producta, is in sinonomie met C. oblongifolia geplaas. Gevolglik sluit Cryptolepis tans 'n totaal van 31 spesies in.
In terme van spesieverskeidenheid, verspreiding en potensiële farmaseutiese en ekonomiese belangrikheid is Cryptolepis een van die belangrikste genusse in die Periplocoideae. Cryptolepis kom dwarsdeur Afrika suid van die Sahara voor, maar ook in die suidelike deel van Jemen, in die Socotra eilandargipel en in suidelike Asië vanaf Indië tot suidelike Sjina, Taiwan, die Filippyne en Indonesië. Die spesies groei hoofsaaklik in tropiese woude of in savanna, maar 13 spesies word in droë omgewings aangetref.
Die meeste Cryptolepis spesies is in vier diversiteitsentrums langs die ooskus van Afrika en op Socotra gekonsentreer. Hierdie brandpunte word met beide droë- en woudtoevlugnisse geassosieer in gebiede wat beskou word as plaaslike sentrums van endemisme vir 'n aantal ander planttaksons. Die filogenetiese ontleding van Cryptolepis het getoon dat hierdie brandpunte ook herhaaldelik deur verskillende Cryptolepis spesiegroepe gekoloniseer is. Benewens die invloed van klimaatsverskuiwings, het edafiese toestande en ook vuur spesiesdiversiteit en verspreiding in Cryptolepis duidelik beïnvloed.
Makro- en mikromorfologiese ondersoeke het aangetoon dat 'n verskeidenheid eienskappe insluitende groeivorm, blaarvorm, blaar epidermale eienskappe, tipe bearing, bou van bloeiwyses, blomstruktuur en eienskappe van die saadhuid diagnostiese waarde op spesievlak in Cryptolepis besit. Die spesies kan egter slegs noukeurig geïdentifiseer word deur 'n kombinering van eienskappe te gebruik.
Die molekulêre filogenetiese ontledings het aangetoon dat Cryptolepis parafileties is en ten einde 'n monofiletiese genus daar te stel, is voorgestel dat die omskrywing van Cryptolepis uitgebrei word deur insluiting van Parquetina as 'n sinoniem.
Sekere vegetatiewe en voortplantingskenmerke het 'n hoë mate van homoplasie getoon, en het op 'n hoë mate van morfologiese plastisiteit gedui. Dit is veral op spesievlak in Cryptolepis oblongifolia waargeneem. Hierdie plastisiteit, gekoppel met die hoë mate van verdraagsaamheid teenoor versteuring, het tot gevolg gehad dat Cryptolepis oblongifolia die wydste verspreiding in die genus het
A taxonomic study of Cryptolepis (Apocynaceae) in southern Africa
No full textA taxonomic revision of Cryptolepis R.Br. (Apocynaceae, Periplocoideae) in southern Africa is presented. This revision comprises investigations into the micromorphology of pollen, translators, leaf anatomy, leaf epidermal surfaces and seed coat surfaces; macro-morphology of the plant parts; nomenclature, geographical distribution and ecological characteristics of the six species indigenous to southern Africa. The investigations resulted in descriptions with appropriate nomenclature and the compilation of an identification key for the six species. All available type specimens related to Cryptolepis in southern Africa were studied. Where holotype specimens could not be located lectotypes were designated from available isotypes or syntypes. Where no isotypes or syntypes could be located, neotypes were declared. In cases where only syntypes had been given by authors of species names, lectotypes were declared. Cryptolepis is widely distributed throughout the northern parts of southern Africa, with the largest concentration of species in the north-east of the region. Some species, such as C. oblongifolia, are common, while others have very restricted distribution ranges. C. delagoensis, for instance, is known from only six localities in southern Africa. Only C. decidua occurs in the desert and semi-desert habitats in the north-west of southern Africa, while the other five species inhabit savannah, sand forest, riverine -, afromontane - and coastal vegetation in the eastern parts of the region. In southern Africa Cryptolepis consists of slender climbers, occasionally small suffrutices or branching shrubs with white latex and interpetiolar ridges with dentate colleters. Leaves are opposite, decussate or rarely fascicled. A combination of leaf anatomy and leaf surface characteristics proved to be taxonomically useful for distinguishing the southern African species. The fruit consists of paired follicles. Seeds of Cryptolepis are adapted to anemochoric dispersal through a coma of hair at the micropylar end. All southern African species can be differentiated from each other using cellular arrangement and primary and secondary sculpture of their seed coat surfaces. Floral characteristics are taxonomically useful for distinguishing Cryptolepis from related genera. Cryptolepis is characterized by a distinct corolla tube, with corolla lobes always longer than the corolla tube, corona lobes arising just above the middle of the corolla tube, and usually included in the corolla tube, and stamens arising at the lower third of the corolla tube, with interstaminal discs always present. Two, semi-inferior, apocarpous ovaries are present. The styles unite to form a compound style and pentagonal style-head, on which five translators are formed by epithelial cells in grooves alternating with the stamens. The anthers are fused to the style head, forming a gynostegium. In the five species that occur in the eastern parts of the region flowers are arranged in cymes. Prominent, paired colleters are found at the inner bases of the sepals. The corona lobes may be oblong, clavate, deltoid or awl-shaped. The corona lobes are always included in the corolla tube, where they touch or fit tightly, forming a dome which closes off the lower corolla tube. Pollen characteristics and translator shape are similar for all five species and have little taxonomic value. C. decidua differs from the eastern species in that its flowers are solitary. The colleters at the inner sepal bases are replaced by trichomes. The corona lobes are filiform, do not form a dome over the lower corolla tube and may be exserted from the corolla tube mouth. Pollen tetrad shape and translator shape and size differ markedly from those of the other species. All these unique characteristics in C. decidua suggest that this species may not belong in Cryptolepis
Disturbance factors related to conservation of biodiversity in large-scale ecological networks
No full textThesis (PhD)--Stellenbosch University, 2014.ENGLISH ABSTRACT: Globally, habitat transformation causes biodiversity loss, with the transformed matrix often affecting the disturbance regime in remnant natural patches. In South Africa, significant parts of the Indian Ocean coastal belt and grassland biomes have been transformed into commercial forestry plantations of alien trees, which are detrimental to local biodiversity. Consequently, large scale ecological networks (ENs) of remnant natural vegetation, maintained areas (e.g. firebreaks) and special landscape features (e.g. rocky outcrops and wetlands) have been implemented among forestry compartments to offset the negative effect of this land use on biodiversity. Different grassland areas, which constitute a major portion of ENs, were managed in different ways, as governed by their primary purpose (e.g. fire protection or conservation). The overall aim of this study was to determine how grassland floral and grasshopper herbivore communities responded to different disturbances (mowing, burning and grazing), and how we can adjust management of the major disturbances to effectively conserve these major components of biodiversity in ENs.
Sampling was carried out in the commercial forestry ENs in the lower-elevation Zululand area and adjacent reserve area iSimangaliso Wetland Park, as well as in the forestry ENs in the higher-lying Midlands and adjacent iMpendle Nature Reserve. Both the reserves or protected areas (PAs) acted as reference sites, while other sites were chosen to represent the predominant disturbances in ENs at each locality: mowing, annual vs. longer-rotation burning, time since last fire, and domestic cattle grazing. In the Zululand subtropical grassland (chapter 2), I explored the effect of frequent mowing on firebreaks, and the effect of patch size and isolation on plant communities in non-firebreak natural areas of the EN. Frequent mowing resulted in plant species loss and a shift in species composition of firebreaks. Furthermore, small, isolated patches in the EN far away from the PA border had lower plant species richness and greater species turnover than wide, interconnected corridors near the PA border, which, in turn, was similar to reference sites in the PA. As plant species were lost from frequently-mown firebreaks and small, isolated patches in the EN, I recommend that this management practice should be confined to demarcated areas (e.g. forestry compartment edges and firebreaks) and that creation of wide, interconnected corridors should be prioritized when designing ENs.
In higher elevation Afromontane grassland (chapter 3), I investigated the effect of annual burning on plant communities in firebreaks by comparing them to less frequently burned grassland in the EN and PA, respectively. Grazing by domestic cattle was taken as an embedded factor for firebreak and less frequently burned sites in the EN. There were three firebreak types: annually-burned with heavy cattle grazing (plantation firebreaks), annually-burned with light cattle grazing (peripheral firebreaks), and annual burning without cattle grazing (PA firebreaks). Burned reference grassland in the EN and PA hosted plant communities that were similar in species richness, composition and turnover. This was also the case for lightly-grazed peripheral EN firebreaks and PA firebreaks. However, species composition and turnover of plantation EN firebreaks with heavy cattle grazing differed from that in the other two firebreak types. Although not significant (P12 months prior to sampling), ungrazed grassland in the PA. Burning and grazing both caused a change in plant species composition that went hand in hand with an increase in plant species richness and turnover. However, burning (burned vs. unburned) only affected plant communities in ungrazed grassland in the PA. Similarly, the presence of large mammalian grazers (EN vs. PA) only affected plant communities in unburned grassland. Unburned plant communities grazed by domestic cattle in the EN were similar to those in the PA grazed by indigenous black wildebeest, indicating that cattle grazing simulates, at least to some degree, the effect of indigenous ungulate grazing. Nevertheless, heavily-grazed grassland had less plant species than moderately-grazed grassland in the EN. I recommend that burning and grazing should continue in grassland ENs, as these natural disturbances are necessary to maintain diverse and dynamic ecosystems. Nevertheless, managers should instigate cattle grazing with caution, as high intensity grazing can be detrimental to conservation efforts.
In Chapter 5, I examined the effect of annual burning, cattle grazing (presence vs. absence) and time since last fire on grasshopper assemblages in Afromontane grassland. In general, grasshoppers benefitted from disturbance, and were remarkably resilient to different disturbance regimes. Grasshopper species richness and their abundance were both greatest in annually-burned firebreaks with light cattle grazing, and lowest in moribund grassland in the PA which had not been burned for several years. Yet, time since last fire only affected grasshopper communities in the absence of large grazers (in the PA). None of the individual disturbances had an effect on the grasshopper assemblage. Rather, these insects responded to the combined effect of annual burning with cattle grazing. Sites were similar in grasshopper species richness, composition and abundance whenever either annual burning or cattle were absent, which suggests that these two disturbances drive changes in the grasshopper assemblage in these grasslands. Although grasshoppers benefited from annual burning with light cattle grazing, I would not recommend this disturbance regime outside firebreaks. Rather, management of other grassland areas in the EN should adapt longer fire-return intervals with a rotational cattle grazing system, so that undisturbed habitat is provided for other sensitive taxa.
In conclusion, grassland plants and grasshoppers benefited from some form of disturbance, but were lost from small, isolated patches in the EN, as well as from areas with high disturbance frequency and intensity. Simulation of natural disturbances (moderate levels of fire and grazing) in wide, interconnected corridors is necessary for maintaining diverse and dynamic grassland ecosystem in ENs among commercial forestry plantations.AFRIKAANSE OPSOMMING: Omskepping van natuurlike habitat na lande of plantasies veroorsaak biodiversiteitsverlies wêreldwyd. Boonop het sulke veranderinge dikwels 'n effek op die versteurings binne-in oorblywende kolle natuurlike plantegroei wat verreikende gevolge kan hê. Groot gedeeltes van die Suid-Afrikaanse grasveldbioom is omskep in bosbou plantasies wat bestaan uit uitheemse bome wat 'n baie groot nadelige effek op plaaslike biodiversiteit het. Daarom is grootskaalse ekologiese netwerke (EN’e), wat bestaan uit oorblywende kolle natuurlike plantegroei, brandbane en spesiale habitattipes in die landskap (bv. rotsriwwe en vleilande), tussen bosbouplantasies geïmplimenteer met die doel om die negatiewe effek van plantasies op plaaslike biodiversiteit te verlig. Bestuur van grasvelde, wat 'n groot gedeel van EN’e uitmaak, wissel dikwels en hang af van hulle primêre doel (bv. beskerming van plantasies teen wegholveldbrande of natuurbewaring). Die doel van hierdie projek was om vas te stel hoe plant- en springkaangemeenskappe in grasvelde reageer op verskillende versteurings (grassny, brand en beweiding), en die optimale bestuur van die versteurings om die biodiversiteit in grasvelde beter te bewaar.
Steekproewe is geneem in EN’e tussen bosbouplantasies in die laagliggende Zululand en langsliggende wêrelderfenisgebied, iSimangaliso Wetland Park, asook in die hoërliggende Midlands en langsliggende iMpendle Natuurreservaat (NR). NR’e het as verwysing gedien waarteen die effek van grassny, frekwensie van brande, tydsverloop vanaf die laaste brand, en beweiding deur beeste, wat tipiese versteuringe in EN’e is, gemeet is.
In hoofstuk 2 het ek vasgestel wat die effek van grassnyfrekwensie op plantgemeenskappe in brandbane is, en hoe plantgemeenskappe in subtropiese grasveld in die res van die EN reageer op die grootte en strukturele isolasie van oorblywende kolle natuurlike plantegroei. 'n Hoë grassnyfrekwensie het 'n verandering in die spesiesamestelling van plantgemeenskappe in brandbane veroorsaak wat gepaard gegaan het met spesiesverlies. Terselfdertyd was daar minder plant spesies in klein, geïsoleerde kolle natuurlike plantegroei as wat daar in wyer, aaneenskakelende gange nader aan die natuurreservaatgrens was. Laasgenoemde het plantgemeenskappe bevat wat baie soortgelyk aan die in die natuurreservaat was. Daarom stel ek voor dat die skep van wye, aaneengeskakelde natuurlike habitat prioriteit moet geniet wanneer nuwe EN’e ontwerp word, en dat gras slegs gereeld gesny moet word in spesifieke, afgebakende areas (bv. brandbane). Die rede hiervoor is dat hierdie bestuurspraktyk nie bevorderlik was vir die bewaring van plantdiversiteit in EN’e nie. In hoofstuk 3 het ek gekyk hoe die plantgemeenskappe in brandbane daarop reageer om elke jaar gebrand te word deur hulle te vergelyk met Afrikaberg grasveld in die EN en NR wat minder gereeld gebrand word. Beweiding deur beeste is gesien as 'n integrale deel van die EN. Ek het onderskei tussen plantasiebrandbane met swaar beweiding, randbrandbane met ligte beweiding en brandbane in die NR sonder beweiding. Die plantspesiesamestelling van brandbane, met ligte of geen beweiding nie, het verskil van grasvelde wat minder gereeld gebrand word. Tog is die hoeveelheid plantspesies nie geraak nie. Alhoewel die plantgemeenskappe in ligbeweide brandbane soos die in onbeweide brandbane in die NR was, het die plantspesiesamestelling van beide verskille getoon wanneer hulle vergelyk is met plantasiebrandbane wat swaarder deur beeste bewei is. Plantspesierykheid in plantasiebrandbane was boonop heelwat laer as wat in NR grasvelde gevind is, en daar was heelwat meer kaal grond in plantasiebrandbane as in enige van die ander areas. Oor die algemeen het plantspesiesrykheid van brandbane nie daaronder gely om elke jaar gebrand te word nie, maar kwesbare plantgemeenskappe in brandbane het wel daaronder gely om swaar bewei te word. Daarom stel ek voor dat jaarlikse brande tot brandbane beperk word en dat beeste se toegang tot brandbane streng beheer word. In die hoofstuk 4 ondersoek ek die effek van beweiding deur beeste (teenwoordigheid teenoor afwesigheid, sowel as beweidingsintensiteit) op die plantspesiesrykheid en samestelling van gebrande en ongebrande Afrikaberg grasvelde wat minder gereeld gebrand word. Die minste plant spesies is aangeteken in ongebrande, onbeweide grasveld in die NR. Brande en beweiding het albei 'n effek op plantspesiesamestelling gehad wat gepaard gegaan het met 'n toename in plantspesiesrykheid. Plantgemeenskappe in grasvelde wat onlangs (<12 maande voor die steekproef geneem is) gebrand is, het slegs van die in ongebrande grasvelde verskil wanneer nie een van die twee areas bewei is nie. Op 'n soortgelyke trant het die teenwoordigheid van beeste (EN teenoor NR) slegs n effek gehad in ongebrande grasvelde. Ongebrande plantgemeenskappe in die EN wat deur beeste bewei is, was baie soos die in die NR wat deur swartwildebeeste bewei is. Dit dui daarop dat beeste die effek van inheemse wildsoorte tot 'n mate naboots. Des nieteenstaande die bogenoemde, het swaar-beweide grasvelde minder plantspesies gehad as grasvelde wat slegs matig bewei is. Ek stel voor dat brande en beweiding deel moet vorm van die bestuur van grasvelde in EN’e, want hierdie natuurlike versteuringe dra by tot 'n diverse, dinamiese grasveldekosisteem. Tog moet bestuurders versigtig wees wanneer hulle die plaaslike gemeenskap se beeste in EN’e toelaat, want swaar beweiding kan bewaringsinisiatiewe in die wiele ry. In hoofstuk 5 het ek die klem na springkane verskuif, en die effek van jaarlikse brande, beweiding deur beeste (teenwoordigheid teenoor afwesigheid) en tydsverloop sedert laaste brand op hierdie sensitiewe insekte in Afrikaberg grasvelde ondersoek. Alhoewel springkaangemeenskappe baat gevind het by versteuringe, het hulle nie beduidend gereageer op enige van die indiwiduele versteuringe nie. Die digste sprinkaan bevolking met die hoogste spesies diversiteit is aangeteken in brandbane in die EN wat liggies deur beeste bewei is. Darenteen is die laagste bevolking en spesies diversiteit aangeteken in grasvelde in die NR wat groot hoeveelhede dooie plantmateriaal bevat wat aandui dat hierdie grasvelde nie onlangs gebrand het nie. Springkaangemeenskappe in gebrande grasvelde het slegs van ongebrande grasvelde verskil wanneer nie een van die twee bewei is nie. Die sleutelkombinasie van versteuringe wat die rykheid en samestelling van springkaangemeenskape bepaal het, was 'n hoë brandfrekwensie (soos in brandbane) en beweiding deur beeste. Wanneer een van hierdie versteuringe afwesig was, was springkaangemeenskappe tussen verskillende areas dieselfde. Alhoewel springkaangemeenskappe daarby baat gevind het wanneer brandbane elke jaar gebrand en deur beeste bewei is, kan ek nie hierdie bestuurspraktyk vir die res van die EN aanbeveel nie. Grasvelde in die res van die EN behoort eerder minder gereeld (elke 2-4 jaar) gebrand en met 'n rotasiestelsel bewei word. Sodoende sal brandbane voorsien in die behoeftes van springkane, en die res van die EN in die behoeftes van sensitiewe taksa wat onversteurde habitat benodig om te floreer.
My slotsom is dat versteuringe nodig is om die volle diversiteit van plante en springkane en die dinamika binne-in grasvelde te bewaar. Tog verdwyn daar plantspesies uit areas met 'n hoë versteuringsintensiteit of frekwensie en klein, geïsoleerde kolle natuurlike plantegroei in die EN. Daarom beveel ek aan dat natuurlike versteuringe (brande en beweiding) matig toegepas moet word in wye, aaneengeskakelde gange in die EN. Hierdie benadering tot natuurbewaring kan biodiversiteit tussen bosbouplantasies beveilig teen verdere verlies.Doctora
Biodiversity value of grassland ecological networks in afforested areas, KwaZulu-Natal, South Africa
No full textThesis (MSc)--University of Stellenbosch, 2011.ENGLISH ABSTRACT: The current biodiversity crisis requires creative initiatives for mitigating further
biodiversity loss. The use of ecological networks (ENs) is such an initiative. The South
African forestry industry recognizes that there is loss of biodiversity at the smaller patch
scale, while attempting to mitigate this loss at the landscape scale by implementing largescale
ENs.
The aim of this study was to determine how representative grassland biodiversity in
ENs are of similar habitat in a nature reserves (NR). The study was conducted in the northeast
of the KwaZulu-Natal Province, adjacent iSimangaliso Wetland Park, which is a natural
World Heritage site. A systematic approach compared a wide range of taxa, namely plants,
decomposition macrofungi, vertebrates (birds and large mammals) and faunal manifestations
(e.g. molehills, dung and ant nests) between the EN and nature reserve, while controlling for
differences in disturbance regime. Species richness was compared using Mann-Whitney U
tests, while differences in species composition were determined using Correspondence
Analyses, Multi-Dimensional Scaling and Analyses of Similarity.
Grassland ENs had significantly less plant species. In addition, there were differences
in plant and fungi species composition. Differences were probably caused by (1) degree of
isolation i.e. proximity to source habitat patches in the surrounding matrix, and (2) habitat
quality. Habitat quality was determined by local disturbance regimes (e.g. grazing and fire)
and plantation-induced drought for plants, and size and amount of coarse woody debris for
fungi. In addition, significant differences in abundances of mole hills (NR>EN) and small
mammal burrows (EN>NR) might have had an effect on succession and regeneration of plant
communities.
There were differences in plant species composition between grassland EN and that at
the adjacent nature reserve. However, differences between EN and NR were small when
compared to differences between habitat types at the landscape spatial scale. It is concluded
that grassland ENs among forestry plantations contribute to biodiversity conservation in the
commercially-productive landscape. This approach to land use planning should be explored
for other commercial land uses.AFRIKAANSE OPSOMMING: Die huidige biodiversiteitskrisis vereis kreatiewe strategieë om ‘n verdere verlies in
biodiversiteit te bekamp. Ekologiese Netwerke (EN’e) is een voorbeeld van sulke kreatiewe
strategieë. Die Suid Afrikaanse bosbou-industrie erken die verlies in biodiversiteit wat
kenmerkend in plantasies gevind word. Implementering van grootskaalse EN’e kan egter die
verlies aan biodiversiteit, wat in plantasies ondervind word, temper.
Die doel van hierdie studie was om vas te stel hoe goed biodiversiteit in grasveld EN’e
soortgelyke habitat in ‘n nabygeleë natuurreservaat verteenwoordig. Die studie was uitgevoer
in die noordooste van KwaZulu-Natal, langs iSimangaliso Wetland Park wat ‘n
wêrelderfenisgebied is. Ons het ‘n stelselmatige benadering gevolg waartydens ‘n wye
verskeidenheid taksa, naamlik plante, makro-fungi, vertebrate (groot soogdiere en voëls) en
tekens van diere-aktiwiteit (bv. miersneste, dieremis en molshope), in die EN vergelyk is met
die van ‘n natuurreservaat terwyl ons vir verskillende versteuringe gekontrolleer het.
Spesiesrykheid is vergelyk met Mann-Whitney U toetse terwyl verskille in
spesiessamestelling vasgestel is met Correspondence Analyses, Multi-Dimensional Scaling en
Analyses of Similarity.
Daar was ‘n statisties beduidende verskil in die hoeveelheid spesies tussen grasveld
EN’e en die natuurreservaat. Grasveld EN’e het minder plant spesies gehad. Boonop was daar
verskille in die samestelling van plant en fungi gemeenskappe. Verskille was waarskynlik
veroorsaak deur (1) isolasie of die hoeveelheid nabygeleë habitatbronne in die omliggende
omgewing, en (2) habitat kwaliteit. Habitat kwaliteit word bepaal deur versteuringe (bv. brand
en beweiding) en die uitdrogingseffek van plantasies vir plante, en die hoeveelheid en grootte
van growwe houtagtige puin vir fungi. Daar was ook beduidende verskille in die hoeveelheid
molshope (NR>EN) en klein soogdier gate (EN>NR), wat moontlik ‘n effek kon hê op
suksessie en herstel van plantgemeenskappe.
Daar was verskille in plantspesiessamestelling tussen grasveld EN’e en die van die
langsliggende natuurreservaat. Hierdie verskille was egter klein wanneer dit vergelyk word
met die verskille tussen verskillende soorte habitatte in die landskap. Daarom kom ons tot die
gevolgtrekking dat grasveld EN’e tussen bosbouplantasies bydra tot die bewaring van
biodiversiteit in kommersiële landskappe. Hierdie benadering tot grondgebruik behoort verder
verken te word vir ander kommersiële bosbou en boerderypraktyke.Master
A taxonomic study of the genus cryptolepis (periplocoideae: apocynaceae)
No full textCryptolepis R.Br. (Apocynaceae, Periplocoideae) was taxonomically revised. Detailed descriptions of macro and micro-morphology, palynology, geographic distribution and ecological characteristics were presented. An identification key to the species was compiled and the nomenclature of all species was revised while all available type material was studied and lectotypes and neotypes were designated where necessary. Molecular phylogenetic analyses, based on the gene regions ITS, trnD–T and trnT–F, of representative species of 28 periplocoid genera and 22 Cryptolepis species were presented and the monophyly of Cryptolepis was evaluated. Historically a total of 81 species names and four subspecies names were published for Cryptolepis. However, a large number of species names were later placed in synonymy or transferred to other genera, while several new combinations were published. This resulted in a total of 29 accepted Cryptolepis species at the commencement of this study. Three new species, C. ibayana, C. thulinii and C. villosa, resulted from this study and the latter two were described in this thesis. One species, C. producta, was synonymised with C. oblongifolia. Cryptolepis, therefore, comprises a total of 31 species at present. In terms of species diversity, distribution and potential pharmaceutical and economic value, Cryptolepis is one of the most significant genera in the Periplocoideae. Cryptolepis grows throughout sub-Saharan Africa, the southern parts of Yemen, the island archipelago of Socotra, and southern Asia ranging from India to southern China, Taiwan, the Philippines and Indonesia. Most of the species grow in tropical forests or savannah, but 13 species are also adapted to arid environments. The majority of Cryptolepis species are concentrated in four centres of diversity along the east coast of Africa and on Socotra. These hotspots are associated with both arid and forest refugia in areas which have been regarded as local centres of endemism for a number of other plant taxa. The phylogenetic analysis of Cryptolepis indicates that most of these hotspots were colonized repeatedly by different Cryptolepis groups. In addition to the influence of climate shifts, edaphic conditions and also fire had a significant influence on species diversity and distribution in Cryptolepis. Macro and micro-morphological investigations indicated that numerous characters, including growth form, leaf shape and size, leaf epidermal characters, venation, inflorescence structure, floral structure and seed coat surface characters, are of diagnostic value at species level in Cryptolepis. However, the species can only be accurately identified by using a combination of these characters. The molecular phylogenetic analyses revealed that Cryptolepis is paraphyletic and, in order to establish a monophyletic genus, it was proposed that the circumscription of the genus be broadened to include Parquetina as a synonym of Cryptolepis. Several vegetative and reproductive characters showed a high degree of homoplasy, suggesting a high degree of morphological plasticity. This plasticity was also found at species level in C. oblongifolia, which showed significant variation in vegetative and reproductive features. This, together with a high tolerance for disturbance, has resulted in C. oblongifolia becoming the most widely distributed of all Cryptolepis species
Daily-life executive functions and bimanual performance in children with unilateral cerebral palsy
No full textAim: To explore daily-life reported executive functions and their relation with bimanual performance in children with unilateral cerebral palsy (CP). Method: In this cross-sectional study of 46 children with unilateral CP (mean age 11 years 10 months, standard deviation 2 years 10 months), executive functions were evaluated using the Behavior Rating Inventory of Executive Function (BRIEF) and bimanual performance with the Assisting Hand Assessment (AHA) and Children's Hand-use Experience Questionnaire (CHEQ). One-sample z-tests were used to compare participants' executive functions with population norms, while taking autism spectrum disorder (ASD, n = 16) as a comorbidity into account. Moreover, we used regression analysis to estimate the effect of manual ability (Manual Ability Classification System levels: I = 25, II = 15, III = 6) and having a comorbid diagnosis of ASD on executive functions (p < 0.05, R2). Lastly, non-parametric correlations (rs, p < 0.05) were calculated between the BRIEF, CHEQ, and AHA. Results: In general, executive functions in children with unilateral CP were poorer compared with the normative mean (p <= 0.024). However, when excluding participants with ASD, no difference compared with the normative mean was found. A significant effect of manual ability was found for Inhibition (p = 0.042), while ASD effects were found for most of the BRIEF subscales (p <= 0.001). Multiple significant correlations were found between the BRIEF and CHEQ (rs = -0.50 to -0.29), while only the BRIEF subscale Inhibition was significantly correlated with the AHA (rs = -0.35). Interpretation: A higher number of children with unilateral CP exhibit difficulties in daily-life executive functions, which appear to be mainly co-occurring with ASD. Manual ability was a significant factor of inhibition-related behavioural challenges. Furthermore, there seems to be a relation between impaired executive functions and decreased bimanual performance. The findings emphasize the importance of further research, including performance-based assessments of executive functions in children with unilateral CP.Founding:
The Flemish Research Foundation (FWO project, grant G0C4919N; FWO fellowship, grant 11PP224N).
Acknowledgements
The present study was funded by the Flemish Researc Foundation (FWO project, grant G0C4919N). Alexandra Kalkantzi, as shared first author, was supported by funding from the European Commission, Horizon Europe
Research and Innovation Action under grant agreement number 101057309, in the context of the AINCP project. Lize Kleeren, as shared first author, was funded by an FWO fellowship (grant 11PP224N). We thank all participants and their families for their willingness to take part in this study. We also thank Geert Molenberghs for his statistical advice and Nofar Ben Itzhak for her insights in the analyses
Fig 2 from: Joubert-Van der Merwe L, Pryke JS (2018) Is cattle grazing more important than landscape heterogeneity for grasshoppers in Afromontane grassland? Journal of Orthoptera Research 27(1): 13-21. https://doi.org/10.3897/jor.27.15027
No full textFig 3 from: Joubert-Van der Merwe L, Pryke JS (2018) Is cattle grazing more important than landscape heterogeneity for grasshoppers in Afromontane grassland? Journal of Orthoptera Research 27(1): 13-21. https://doi.org/10.3897/jor.27.15027
No full textFig 1 from: Joubert-Van der Merwe L, Pryke JS (2018) Is cattle grazing more important than landscape heterogeneity for grasshoppers in Afromontane grassland? Journal of Orthoptera Research 27(1): 13-21. https://doi.org/10.3897/jor.27.15027
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