Journal of Threatened Taxa | www.threatenedtaxa.org | 26 August 2020 | 12(11): 16614–16619

 

ISSN 0974-7907 (Online) | ISSN 0974-7893 (Print) 

doi: https://doi.org/10.11609/jott.5728.12.11.16614-16619

#5728 | Received 23 January 2020 | Final received 31 July 2020 | Finally accepted 06 August 2020

 

 

Evaluating threats and conservation status of South African Aloe

 

Samuel O. Bamigboye

 

Botany Department, School of Mathematical and Natural Sciences, University of Venda, 0950, South Africa.

reachtoba@gmail.com

 

 

 

Editor: Martin Potgieter, University of Limpopo, Sovenga, South Africa. Date of publication: 26 August 2020 (online & print)

 

Citation: Bamigboye, S.O. (2020). Evaluating threats and conservation status of South African Aloe. Journal of Threatened Taxa 12(11): 16614–16619. https://doi.org/10.11609/jott.5728.12.11.16614-16619

 

Copyright: © Bamigboye 2020. Creative Commons Attribution 4.0 International License.  JoTT allows unrestricted use, reproduction, and distribution of this article in any medium by providing adequate credit to the author(s) and the source of publication.

 

Funding: None.

 

Competing interests: The author declares no competing interests.

 

 

Abstract: South Africa is one of the biodiversity hotspots for Aloe in Africa.  This makes it important to evaluate the conservation status and threats to this genus.  The South African National Biodiversity Institute (SANBI) Red List was employed to evaluate these two factors.  Results revealed that 44% of all species in this genus are of conservation concern with the majority of them facing threats.  This study recommends that more attention such as strengthening the protection of these species and controlling the threats identified in this study should be given to species in this genus in terms of conservation management to reduce their risk of extinction.

 

Keywords: Asphodelaceae, biodiversity loss, extinction risk, hotspot, threatened species.

 

 

 

The genus Aloe belongs to the Asphodelaceae family (Cousins & Witkowski 2012).  Biodiversity hotspots for this genus in Africa are located in Ethiopia, Madagascar and southern Africa (Grace 2009), which coincide with Africa’s main biodiversity hotspots (Daru et al. 2013).

Aloes are important to any ecosystems where they are found (Cousins & Witkowski 2012).  Their nectar is a source of food for many insects (Nicolson & Nepi 2005; Botes et al. 2009a,b) and avians (Symes et al. 2008; Forbes et al. 2009).  They also modulate harsh environmental conditions, which facilitate colonization of the environment by other plant taxa (Wabuyele & Kyalo 2008).  Their mat-like root that is dense assist in preventing soil erosion (Smith & Van Wyk 2009).

Some species of this genus are traded commercially as cosmetics (Grace et al. 2015) and medicine (Bjorå et al. 2015).  This has led Aloe to become threatened, with the majority of species in this genus being included in the Convention on International Trade in Endangered Species of Wild Fauna and Flora (CITES) (Grace 2011).  This implies that conservation of the species in this genus should be given a high priority, especially in areas that are hotspots of this genus (Klopper & Smith 2013).

This study evaluated the conservation status and threats of Aloe in South Africa to determine which species in this genus are threatened, and to determine factors responsible for their risk of extinction.  Unlike some previous studies that mentioned the overall conservation status of the genus Aloe (e.g., Grace et al. 2009; Cousins & Witkowski 2012), this study showed the conservation status and threats each species of Aloe is facing using the South African National Red List, and also quantified in percentages species in this genus under different Red List categories and threat categories. 

 

Methods

This study used the SANBI Red List 2017 version to evaluate threats and conservation status of South African Aloe. The following percentages were calculated:  the species that are highly threatened, threatened and of conservation concern (Critically Endangered, Endangered, Vulnerable, Near Threatened, Rare, and Data Deficient); Aloe species that fall under different categories of threats (Habitat destruction, individual’s collection, invasive species occurrence, fire occurrence, overgrazing, and insect attack); species endemic and non-endemic to South Africa; threatened endemic species; and endemic species that are of conservation concern and different categories of threats (habitat destruction, individual’s collection, invasive species occurrence, fire occurrence, overgrazing, and insect attack) to endemic species.

 

Results and Discussion

Endemic and non-endemic species of the genus Aloe in South Africa

A total of 125 taxa belonging to the genus Aloe were listed in the South African National Red List; 61.6% of species in the genus Aloe found in the South African National Red List are endemic, while 38.4% are non-endemic.  Species endemism is an important factor to be considered in conservation because the loss of endemic species is of high significant impact in biodiversity loss in any geographic areas that they occur (Moraswi et al. 2019).  A population survey of endemic taxa should be encouraged to determine their population size, density, and distribution in order to reveal their current population trend.  This information will inform appropriate conservation measures, which are adaptive to local conditions.

 

Highly threatened, threatened, and species of conservation concern in South African Aloe

The various threat status categories of South African Aloe are: 52.8% (Least Concern), 10.4% (Rare), 2.4% (Data Deficient), 3.2% (Data Deficient, taxonomically problematic), 10.4% (Near Threatened), 11.2% (Vulnerable), 4% (Endangered), 5.6% (Critically Endangered), 44% are of conservation concern (Critically Endangered, Endangered, Vulnerable, Near Threatened, Rare, and Data Deficient).  Species that are highly threatened are referred to as Critically Endangered (Williams et al. 2013) because they are at the brink of extinction.  Aloe species in this study that falls into this category (Table 1) should be given quick conservation intervention such as preventing further collection by people, minimizing habitat loss, and improving on their regeneration potentials to prevent complete extirpation of their populations.  Some plant species are not threatened, but can be flagged and given priority in terms of conservation, and thus be referred to as species of conservation concern (Victor & Keith 2004).  Species of conservation concern in this study that are not threatened should be monitored to determine if they have become threatened (Table 1).  For instance Data deficient taxa could possibly be threatened (Moraswi et al. 2019).  This is why further efforts is required to obtain sufficient information about them in order to determine if they are threatened or not.

 

Threats to South African endemic and non-endemic Aloe species

Percentages of taxa in the genus Aloe in South Africa facing different types of threats are as follows: 41.6% are threatened by habitat destruction, 16.8% are threatened due to individual’s collection, 14.4% threatened by occurrence of invasive species, 5.6% are threatened because of fire occurrences, 11.2% are threatened by overgrazing, 0.8% threatened due to insect attack, while there are no threats found for 42.4% of the taxa.  Aloe species are generally threatened by habitat destruction and collection by people (Klooper et al. 2009), a situation also reflected in this study.  The collection by people are majorly due to medicinal uses and horticultural uses which might be affecting the wild population of these taxa (Grace 2011).  Enforcement of regulation restricting the collections of these taxa should be more encouraged.  It must be noted that a thorough assessment of those species for which their threats are unknown can significantly change the results pattern in the threat categories as presented above.

 

Threats to endemic species of South African Aloe

The results of the percentages of endemic species of South African Aloe facing different kind of threats are as follows: 57% are affected by habitat destruction, 23.4% affected by Individual’s collection, 17% are affected by invasive species, 9% by fire occurrence, 13% by overgrazing, while there are no threats found for 26% of the endemic species.  Habitat destruction and collection by people still stood out among the threats to endemic South African Aloe species.  It is recommended that species for whom their threats are not known (Table 1) be further assessed.  Thus, it is possible that a reassessment of these species can alter the results presented above. 

 

Conservation status of endemic species in South African Aloe

The results of the percentages of endemic Aloe taxa in South Africa on SANBI Red List threat status categories are as follows: 32.4% (Least Concern), 5.2% (Data Deficient taxonomically problematic), 2.6% (Data Deficient), 15.6% (Rare), 15.5% (Near Threatened), 14.3% (Vulnerable), 5.2% (Endangered) and 9.1% (Critically Endangered); 28.6% of the endemic species in this genus are threatened (Critically Endangered, Endangered, Vulnerable); 62.3% of the endemic species are of conservation concern (Critically Endangered, Endangered, Vulnerable, Near Threatened, Rare, and Data Deficient).  Endemic plant species are more vulnerable to extinction (Williams et al. 2013) because they are restricted to certain geographic regions and the total extirpation of their populations in that region automatically result in total extinction of the species (Bamigboye 2019).  This is also being clearly revealed in this study as all the Critically Endangered Aloe species in this study are endemic species, which further supports the notion that a more proactive conservation intervention should be given to these species.

 

Conclusion

This study presents the current conservation status, endemic status and threats that each species of Aloe in South African Red List are facing.  It also quantifies the percentages of species in this genus that fall into different SANBI Red List categories, threat categories, and endemism categories.  This study provides information on the species of Aloe in South Africa that need more conservation attention.  For instance the Critically Endangered species in this study that are all endemic species (Table 1) can be given higher priorities for conservation.  Conservation status of species changes over time (Bamigboye et al. 2016).  It is recommended that South African Aloe should be further evaluated to see if they have become more threatened in recent times or not.  A recent evaluation will also reveal if the ones that are not threatened on SANBI Red List are now threatened.

 

 

Table 1. List of Aloe species in South Africa, their SANBI Red List Status, their endemism status and their threats on SANBI Red List.

Species

SANBI Red List  status

Endemism status

Threats

Aloe aculeata Pole-Evans

Least Concern

Not endemic

No threat

Aloe affinis A.Berger

Least Concern

Not endemic

Habitat destruction

Aloe africana Mill.

Least Concern

Endemic

Habitat destruction

Aloe albida (Stapf) Reynolds

Near Threatened

Not endemic

Habitat destruction

Aloe alooides (Bolus) Druten

Least Concern

Endemic

Habitat destruction

Aloe ammophila Reynolds

Least Concern

Endemic

No threat

Aloe angelica Pole-Evans

Least Concern

Endemic

Habitat destruction

Aloe arborescens Mill.

Least Concern

Not endemic

No threat

Aloe arenicola Reynolds

Near Threatened

Endemic

No threat

Aloe barbara-jeppeae T.A.McCoy & Lavranos

Near Threatened

Endemic

Habitat destruction

Aloe bergeriana (Dinter) Boatwr. & J.C.Manning

Data Deficient

Not endemic

Habitat destruction

Aloe bowiea Schult. & J.H.Schult.

Critically Endangered

Endemic

Habitat destruction

Aloe braamvanwykii Gideon F.Sm. & Figueiredo

Endangered

Endemic

Habitat destruction

Aloe branddraaiensis Groenew.

Least Concern

Endemic

Habitat destruction

Aloe brevifolia Mill. var. brevifolia

Vulnerable

Endemic

Habitat destruction, invasive presence, individual’s collection

Aloe brevifolia Mill. var. depressa (Haw.) Baker

Data Deficient taxonomically problematic

Endemic

Habitat destruction

Aloe broomii Schönland var. broomii

Least Concern

Not Endemic

No threat

Aloe broomii Schönland var. tarkaensis Reynolds

Rare

Endemic

No threat

Aloe buhrii Lavranos

Vulnerable

Endemic

Individual’s collection, habitat destruction

Aloe castanea Schönland

Least Concern

Endemic

No threat

Aloe chabaudii Schönland var. chabaudii

Least Concern

Not endemic

No threat

Aloe challisii Van Jaarsv. & A.E.van Wyk

Vulnerable

Endemic

Individual’s collection, invasive presence

Aloe chlorantha Lavranos

Vulnerable

Endemic

Insect attack

Aloe chortolirioides A.Berger var. chortolirioides

Vulnerable

Not endemic

Habitat destruction, invasive presence, fire occurrences,

Aloe chortolirioides A.Berger var. woolliana (Pole-Evans) Glen & D.S.Hardy

Least Concern

Endemic

Habitat destruction, fire occurrences

Aloe claviflora Burch.

Least Concern

Not endemic

No threat

Aloe comosa Marloth & A.Berger

Least  Concern

Endemic

Individuals collection, habitat destruction

Aloe condyae Van Jaarsv. & P.Nel

Vulnerable

Endemic

Invasive presence

Aloe cooperi Baker

Least Concern

Not endemic

Habitat destruction, overgrazing, invasive presence

Aloe craibii Gideon F.Sm.

Critically Endangered

Endemic

Individual’s collection, fire occurrences, invasive presence, habitat destruction

Aloe cryptopoda Baker

Least Concern

Not endemic

No threat

Aloe dabenorisana Van Jaarsv.

Rare

Endemic

Individual’s collection

Aloe dewetii Reynolds

Least Concern

Not endemic

No threat

Aloe dominella Reynolds

Near Threatened

Endemic

Habitat destruction, overgrazing, fire occurrences, invasive presence

Aloe dyeri Schönland

Least Concern

Not endemic

No threat

Aloe ecklonis Salm-Dyck

Least Concern

Not endemic

Habitat destruction, invasive presence

Aloe excelsa A.Berger var. excelsa

Least Concern

Not endemic

No threat

Aloe falcata Baker

Least Concern

Not endemic

Individual’s collection, overgrazing

Aloe ferox Mill.

Least Concern

Not endemic

Individual’s collection, habitat destruction, overgrazing

Aloe fosteri Pillans

Least Concern

Endemic

No threat

Aloe fouriei D.S.Hardy & Glen

Data Deficient taxonomically problematic

Endemic

Habitat destruction, overgrazing

Aloe framesii L.Bolus

Near Threatened

Endemic

Habitat destruction

Aloe gariepensis Pillans

Least Concern

Not endemic

No threat

Aloe gerstneri Reynolds

Vulnerable

Endemic

Habitat destruction, Overgrazing

Aloe glauca Mill.

Least Concern

Endemic

No threat

Aloe globuligemma Pole-Evans

Least Concern

Not endemic

No threat

Aloe graciliflora Groenew.

Least Concern

Endemic

No threat

Aloe grandidentata Salm-Dyck

Least Concern

Not endemic

No threat

Aloe greatheadii Schönland var. davyana (Schönland) Glen & D.S.Hardy

Least Concern

Not endemic

No threat

Aloe greatheadii Schönland var. greatheadii

Least Concern

Not endemic

No threat

Aloe greenii Baker

Least Concern

Not endemic

No threat

Aloe hahnii Gideon F.Sm. & R.R.Klopper

Near Threatened

Endemic

Habitat destruction

Aloe hardyi H.F.Glen

Rare

Endemic

No threat

Aloe hereroensis Engl. var. hereroensis

Least Concern

Not endemic

No threat

Aloe humilis (L.) Mill.

Least Concern

Endemic

Habitat destruction, individual’s collection

Aloe inconspicua Plowes

Endangered

Endemic

Habitat destruction, overgrazing

Aloe integra Reynolds

Vulnerable

Not endemic

Habitat destruction, invasive presence, fire occurrences

Aloe jeppeae Klopper & Gideon F.Sm.

Least Concern

Endemic

No threat

Aloe kamnelii Van Jaarsv.

Rare

Endemic

No threat

Aloe karasbergensis Pillans

Least Concern

Not endemic

No threat

Aloe knersvlakensis S.J.Marais

Rare

Endemic

No threat

Aloe kniphofioides Baker

Vulnerable

Endemic

Habitat destruction, fire occurrences

Aloe komaggasensis Kritzinger & Van Jaarsv.

Vulnerable

Endemic

Individual’s collection, habitat destruction, overgrazing

Aloe komatiensis Reynolds

Endangered

Not endemic

Habitat destruction, invasive presence

Aloe kouebokkeveldensis Van Jaarsv. & A.B.Low

Rare

Endemic

No threat

Aloe krapohliana Marloth

Data Deficient

Endemic

Individual’s collection, habitat destruction, overgrazing

Aloe lettyae Reynolds

Endangered

Endemic

Habitat destruction, invasive occurrence, overgrazing, fire occurrences

Aloe linearifolia A.Berger

Near Threatened

Endemic

Habitat destruction, overgrazing

Aloe lineata (Aiton) Haw. var. lineata

Least Concern

Endemic

Habitat destruction

Aloe lineata (Aiton) Haw. var. muirii (Marloth) Reynolds

Least Concern

Endemic

No threat

Aloe littoralis Baker

Least Concern

Not endemic

No threat

Aloe longistyla Baker

Data Deficient

Endemic

Individual’s collection, habitat destruction, overgrazing

Aloe lutescens Groenew.

Least Concern

Not endemic

No threat

Aloe maculata All.

Least Concern

Not endemic

No threat

Aloe marlothii A.Berger subsp. marlothii

Least Concern

Not endemic

No threat

Aloe marlothii A.Berger subsp. orientalis Glen & D.S.Hardy

Least Concern

Not endemic

No threat

Aloe melanacantha A.Berger

Least Concern

Not endemic

No threat

Aloe meyeri Van Jaarsv.

Rare

Not endemic

No threat

Aloe micracantha Haw.

Near Threatened

Endemic

Habitat destruction, invasive presence

Aloe microstigma Salm-Dyck

Least Concern

Not endemic

No threat

Aloe minima Baker

Least Concern

Not endemic

Habitat destruction

Aloe modesta Reynolds

Vulnerable

Endemic

Habitat destruction, Invasive presence

Aloe monotropa I.Verd.

Vulnerable

Endemic

Individual’s collection

Aloe mudenensis Reynolds

Least Concern

Endemic

Habitat destruction

Aloe myriacantha (Haw.) Schult. & J.H.Schult.

Least Concern

Not endemic

Invasive occurrences

Aloe neilcrouchii R.R.Klopper & Gideon F.Sm.

Endangered

Endemic

Habitat destruction

Aloe neilcrouchii R.R.Klopper & Gideon F.Sm.

Critically Endangered

Endemic

Habitat destruction

Aloe nubigena Groenew.

Rare

Endemic

Habitat destruction

Aloe parvibracteata Schönland

Least Concern

Not endemic

No threat

Aloe pearsonii Schönland

Vulnerable

Not endemic

Overgrazing

Aloe peglerae Schönland

Critically Endangered

Endemic

Habitat destruction, individual’s collection

Aloe perfoliata L.

Least Concern

Endemic

No threat

Aloe petricola Pole-Evans

Least Concern

Endemic

Habitat destruction

Aloe petrophila Pillans

Rare

Endemic

No threat

Aloe pictifolia D.S.Hardy

Rare

Endemic

No threat

Aloe pluridens Haw.

Least Concern

Endemic

No threat

Aloe pratensis Baker

Least Concern

Not endemic

Habitat destruction, individual’s collection

Aloe pretoriensis Pole-Evans

Least Concern

Not endemic

Habitat destruction

Aloe prinslooi I.Verd. & D.S.Hardy

Near Threatened

Endemic

Individual’s collection and invasive presence

Aloe pruinosa Reynolds

Vulnerable

Endemic

Habitat destruction, individual’s collection, invasive occurrence

Aloe reitzii Reynolds var. reitzii

Near Threatened

Endemic

No threat

Aloe reitzii Reynolds var. vernalis D.S.Hardy

Critically Endangered

Endemic

Individual’s collection

Aloe reynoldsii Letty

Rare

Endemic

Individual’s collection

Aloe rupestris Baker

Least Concern

Not endemic

No threat

Aloe saundersiae (Reynolds) Reynolds

Critically Endangered

Endemic

Habitat destruction, overgrazing, fire occurrences

Aloe sharoniae N.R.Crouch & Gideon F.Sm.

Least Concern

Not endemic

Habitat destruction

Aloe simii Pole-Evans

Critically Endangered

Endemic

Habitat destruction, Invasive presence

Aloe soutpansbergensis I.Verd.

Rare

Endemic

Individual’s collection

Aloe speciosa Baker

Least Concern

Endemic

No threat

Aloe spectabilis Reynolds

Least Concern

Endemic

No threat

Aloe spicata L.f.

Least Concern

Not endemic

No threat

Aloe striata Haw.

Least Concern

Endemic

No threat

Aloe succotrina Lam.

Least Concern

Endemic

No threat

Aloe suffulta Reynolds

Least Concern

Not Endemic

No threat

Aloe suprafoliata Pole-Evans

Least Concern

Not Endemic

No threat

Aloe thompsoniae Groenew.

Rare

Endemic

No threat

Aloe thorncroftii Pole-Evans

Near Threatened

Endemic

Habitat destruction, invasive presence

Aloe thraskii Baker

Near Threatened

Endemic

Habitat destruction, individual’s collection

Aloe vanbalenii Pillans

Least Concern

Not endemic

No threat

Aloe vanrooyenii Gideon F.Sm. & N.R.Crouch

Least Concern

Endemic

No threat

Aloe verecunda Pole-Evans

Least Concern

Endemic

Habitat destruction

Aloe vogtsii Reynolds

Near Threatened

Endemic

Habitat destruction

Aloe vossii Reynolds

Data Deficient taxonomically problematic

Endemic

Habitat destruction, fire occurrences, Invasive presence

Aloe vryheidensis Groenew.

Data Deficient taxonomically problematic

Endemic

Habitat destruction

Aloe zebrina Baker

Least Concern

Not endemic

No threat

 

 

 

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