Evaluating threats and conservation status of South African Aloe

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.


PLATINUM OPEN ACCESS
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 .
Some species of this genus are traded commercially as cosmetics  and medicine . 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 J TT 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 nonendemic 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 nonendemic. 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 J TT  (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.