Encephalartos humilis

Assessor: Sarah Schumann

Sensitive in 2010
Yes
Family
Zamiaceae
Reason for the sensitivity status
This taxon is sensitive as it is threatened with illegal collection of wild individuals, causing population decline. Evidence shows that the Encephalartos genus is in high demand in international trade for ornamental and horticultural purposes as well as local medicinal purposes. The species has a small remaining population size with multiple existing threats, making it vulnerable to further population loss. Releasing data on this species can exacerbate threat and vulnerability.
This species is extremely rare in the wild and is known to be exploited, utilised or traded. The localities of remaining populations need to be protected to avoid any further exploitation, which is likely to drive it to extinction.
Exploitation extent
Significant - wild individuals of the species are known to be exploited, collected, traded or utilized in a targeted manner, and utilisation is widespread, affects the majority of wild populations and/or is causing rapid decline of the wild population.
Justification and references

All South African cycads as well as this species is included in Appendix I of the CITES Convention which lists all species threatened with extinction that are, or may be affected by trade. According to the SANBI Red List Assessment, this species is Vulnerable as it is more threatened by habitat loss as this species is less popular to trade however illegal collecting and harvesting for medicinal purposes is occurring (Donaldson 2009; Donaldson 2003). Cycad species are in trade demand and at risk from illegal collection (Smith 2014; Yeld 2014). Studies present strong evidence of ongoing and accelerating rates of decline in most cycad species due mainly to illegal removal (Okubamichael et al. 2016; Cousins & Witkowski 2017). Research shows that this species is among the 25 of 37 Encephalartos species that is being utilised for traditional medicine (Cousins, 2012). The CITES Trade Database has recorded the trade of the species from 1981-2019 for commercial, personal, scientific, artificial propagation and botanical garden purposes. Sourced from artificial propagation.

CITES trade statistics derived from the CITES Trade Database, UNEP World Conservation Monitoring Centre, Cambridge, UK.

Cousins, S.R., Williams, V.L., & Witkowski, E.T.F. 2012. Uncovering the cycad taxa (Encephalartos species) traded for traditional medicine in Johannesburg and Durban, South Africa. South African Journal of Botany78, 129–138. DOI:10.1016/j.sajb.2011.06.001

Cousins, S.R. and Witkowski, E.T.F., 2017. African cycad ecology, ethnobotany and conservation: a synthesis. The Botanical Review83(2), pp.152-194.

Donaldson, J.S. 2003. Cycads. Status survey and conservation action plan. IUCN/SSC Cycad Specialist Group, Gland, Switzerland; Cambridge, UK.

Donaldson, J.S. 2009. Encephalartos humilis I.Verd. National Assessment: Red List of South African Plants version 2020.1. 

Okubamichael, D. Y., S. L. Jack, J. D. Bösenberg, M. T. Hoffman & J. S. Donaldson. 2016. Repeat photography confirms alarming decline in south African cycads. Biodiversity Conservation 25(11): 2153–2170

Smith, D. 2014. 1 September 2014. South Africa's ancient cycad plants under threat from poachers. The Guardian. Available at: https://www.theguardian.com/world/2014/sep/01/ancient-cycad-plants-under-threat-poachers

Yeld, J. 2014. 7 August 2014. Cycad thieves strike again. IOL. Available at: https://www.iol.co.za/news/cycad-thieves-strike-again-1731799

Population vulnerability
Population is vulnerable: size is <= 2500 mature individuals OR the number of known subpopulations is <= 5 OR range is <= 100km2 OR species at risk of localised extinctions
Justification and references

According to the IUCN Red List, there are 4 500- 10 000 mature individuals remaining in the wild (Donaldson 2010). This species is thought to have declined by 30% in the last 90 years and is expected to decline a further 10% in the next 30 years from over-collecting and habitat loss to pine plantations (Donaldson 2009). Subpopulations are found within private nature reserves and conservancies however are small and fragmented. Donaldson (2003) deems its population decline and habitat reduction as high.

Donaldson, J.S. 2003. Cycads. Status survey and conservation action plan. IUCN/SSC Cycad Specialist Group, Gland, Switzerland; Cambridge, UK.

Donaldson, J.S. 2009. Encephalartos humilis I.Verd. National Assessment: Red List of South African Plants version 2020.1. 

Donaldson, J.S. 2010. Encephalartos humilisThe IUCN Red List of Threatened Species 2010: e.T41917A10594932. https://dx.doi.org/10.2305/IUCN.UK.2010-3.RLTS.T41917A10594932.en

Targeted demographics
Mature (breeding) individuals are killed, significantly weakened or are permanently removed from the wild, OR immature individuals are targeted and this significantly impacts mature (breeding) individuals.
Justification and references

The CITES Trade Database has recorded the trade of live individuals and seeds. Mature individuals are removed from the wild causing population decline (Donaldson 2009; Cousins 2012).

CITES trade statistics derived from the CITES Trade Database, UNEP World Conservation Monitoring Centre, Cambridge, UK.

Cousins, S.R., Williams, V.L., & Witkowski, E.T.F. 2012. Uncovering the cycad taxa (Encephalartos species) traded for traditional medicine in Johannesburg and Durban, South Africa. South African Journal of Botany78, 129–138. DOI:10.1016/j.sajb.2011.06.001

Donaldson, J.S. 2009. Encephalartos humilis I.Verd. National Assessment: Red List of South African Plants version 2020.1. 

Regeneration potential
This species has a slow population growth rate, or the growth rate varies depending on habitat, and there is a poor chance the wild populations will recover from exploitation OR a collector might feasibly harvest the entire extant population removing the chance of subsequent recruitment.
Justification and references

Research shows that cycads are generally long-lived, have slow growth rates, produce low numbers of offspring and have infrequent recruitment (Golding & Hurter 2003, Donaldson 2003, Cousins & Witowski 2017). Viable seed production in Encephalartos populations tends to decline with decreasing population size (Cousins & Witowksi 2017). Smaller subpopulations are more likely to experience declines than larger subpopulations as a result of fragmentation processes.  

Cousins, S.R. and Witkowski, E.T.F., 2017. African cycad ecology, ethnobotany and conservation: a synthesis. The Botanical Review83(2), pp.152-194.

Donaldson, J.S. 2003. Cycads. Status survey and conservation action plan. IUCN/SSC Cycad Specialist Group, Gland, Switzerland; Cambridge, UK.

Golding, J.S. and Hurter, P.J.H., 2003. A Red List account of Africa's cycads and implications of considering life-history and threats. Biodiversity & Conservation12(3), pp.507-528.