African aloe ecology: A review

Cousins, Stephen; Witkowski, E.T.F.

doi:10.1016/j.jaridenv.2012.03.022

Cited by 69 publications

(44 citation statements)

References 72 publications

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“…gracilis var. decumbens (rambling aloes) and Aloe haemanthifolia (stemless aloe)), or occupy fire refugia ( Aloe perfoliata (creeping aloe) and Aloe brevifolia (dwarf aloe)) (Cousins & Witkowski ). However, the traits K. plicatilis possesses that confer fire survival, combined with its occupation of predominantly rocky sites, suggest that it adopts a dual fire survival strategy (both ‘avoidance’ and tolerance).…”

Section: Discussionmentioning

confidence: 99%

Beating the blaze: Fire survival in the fan aloe (Kumara plicatilis), a succulent monocotyledonous tree endemic to the Cape fynbos, South Africa

2015

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Fire is central to the ecology of Mediterranean-type climate ecosystems, but little is known about the fire ecology of succulent plants therein. This study investigated the fire ecology of an arborescent succulent monocot, Kumara plicatilis (L.) G. D. Rowley (Asphodelaceae), a Cape fynbos endemic. Habitat suitability was assessed to determine whether the species tolerates or 'avoids' fire, and fire survival traits (bark thickness and tissue water content) were measured. The population size structure and density of three K. plicatilis populations were assessed after natural fires, and resprouting potential was investigated. Kumara plicatilis adopts a dual fire survival strategy, occupying rocky sites to 'avoid' fire and possessing morphological features that afford fire tolerance, e.g. well-protected apical meristems and thick corky bark. Bark thickness of burned individuals in situ was similar to unburned plants, suggesting that K. plicatilis bark provides effective insulation against fire. Mortality rates were 64%, 40% and 11%, and decreased as rock cover at the population level increased. All three populations showed reduced plant density post-fire, with greater density reductions associated with lower rock cover. Small plants appear most vulnerable to fire damage due to lower absolute bark thickness and plant heights within the flame zone. Kumara plicatilis is an apical sprouter, recovering after fire or mechanical stem damage by onward growth from surviving stem apices, rather than resprouting. Post-fire population recovery therefore likely depends on inter-fire recruitment.

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Section: Discussionmentioning

confidence: 99%

Beating the blaze: Fire survival in the fan aloe (Kumara plicatilis), a succulent monocotyledonous tree endemic to the Cape fynbos, South Africa

2015

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“…Most aloes are self‐incompatible, therefore they rely on animal floral visitors for pollination (e.g. Cousins & Witkowski ; Payne et al . ).…”

Section: Introductionmentioning

confidence: 99%

“…). In return, aloes provide a nectar reward for many avian and insect species, especially during winter when alternative food sources are scarce (Symes & Nicolson ; Cousins & Witkowski ; Kuiper et al . ).…”

Section: Introductionmentioning

confidence: 99%

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Predation of fruit and seed of Aloe pretoriensis – A little known effect on reproductive output in aloes

2019

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The effect of seed predation by phytophagous/parasitoid wasps on the reproductive output of aloes is relatively unknown. In this study, conducted at a nature reserve in Pretoria East, South Africa, the range of insects utilising Aloe pretoriensis (Asphodelaceae) fruits and/or seeds and the impact of this usage on its reproductive output were investigated. Using a GLMM, we explored the effects of morphological features (e.g. floral display size) and selected ecological factors (viz. distance between the aloes and conspecifics and other surrounding vegetation) on fruit utilisation and seed predation. A variety of insect visitors to A. pretoriensis (mainly bees and wasps) were identified including a number of seed predators and parasitoids. Evidence of phytophagy in dissected flowers showed increasing evidence of fruit utilisation and seed predation over an 8-week period. Emergence boxes with infructescences revealed a range of insect phytophages (and their associated parasitoids) in the aloe fruits and seeds: the drosophilid fly, Apenthecia and six species of wasp -five of them associated with ultilisation of aloe fruits/seeds for the first time: Eurytoma aloineae (Chalcididae), Mesopolobus sp., Pteromalus sp., and c.f. Chlorocytus in the Pteromalidae, Bracon sp. (Braconidae) and Pediobius (Eulophidae). Fruit set ranged between 48% and 93%, with an average of 76%, while average percentage utilisation of fruits was 29%, ranging between 7% and 68%. Average seed set was 23 seeds per fruit and average percentage seed predation 21% (range: 0-51%). Fruit utilisation was found to be significantly negatively correlated with distance to the nearest flowering bush (usually Helichrysum kraussii), but display size did not significantly affect fruit utilisation, nor did distance to conspecifics. Aloe pretoriensis thus serves as host to a variety of phytophagous insects and their associated parasitoids, which impacts considerably on its reproductive output with possible implications for the future conservation of this aloe species.

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“…This aloe has a less bitter taste compared to other species because of lower concentration of aloin 3 . Aloe species are well characterized on the African Continent, Arabian Peninsula, Madagascar, and eastern Indian Ocean Islands 4 . Aloe, native to South Africa, is now spread worldwide.…”

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confidence: 99%

Effect of Carbon Sources and Sucrose Concentrations on Shoot Organogenesis of Aloe saponaria

Kim¹,

Baskar²,

Park³

2016

Biosci., Biotech. Res. Asia

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In the present study, the effect of various carbon sources and sucrose concentrations on in vitro organogenesis of Aloe saponaria was investigated and a rapid micropropagation protocol was developed from in vitro-derived meristem explants. Meristem explants were cultured in initial shoot regeneration media with five different carbon sources (fructose, glucose, lactose, maltose, and sucrose), and sucrose as the best carbon sources for shoot regeneration and shoot elongation was investigated at five different concentrations (

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African aloe ecology: A review

Cited by 69 publications

References 72 publications

Beating the blaze: Fire survival in the fan aloe (Kumara plicatilis), a succulent monocotyledonous tree endemic to the Cape fynbos, South Africa

Beating the blaze: Fire survival in the fan aloe (Kumara plicatilis), a succulent monocotyledonous tree endemic to the Cape fynbos, South Africa

Predation of fruit and seed of Aloe pretoriensis – A little known effect on reproductive output in aloes

Effect of Carbon Sources and Sucrose Concentrations on Shoot Organogenesis of Aloe saponaria

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