#PROTECT

Mossel Bay’s guardian buchu – scarcer than rhinos

JUNE 24, 2022 | Written & photographs by Sandra Falanga

Above: Diosma aristata, Mossel Bay’s endemic buchu, is red listed as Critically Endangered. A new population was discovered during the City Nature Challenge. The species faces threats such as urban encroachment, alien invasive plants and human irreverence. Conserving the species has so far saved a pocket of fynbos and all its plants and creatures from development.

Mossel Bay has its own endemic buchu species, Diosma aristata. It is scarcer than rhinos. Despite this, this little buchu is punching well above its weight. It has been the guardian of remnant fynbos on the edge of suburbia: it’s very presence is the only reason this patch has not been lost forever. And more recently, amidst great excitement, another population of more than 60 plants were found during the City Nature Challenge.

Diosma aristata is a small, upright bush. It has lime green leaves, with sharp pointy tips, creamy white flowers and it reseeds after fire. In fact, it needs fire to survive! Seeds are held in partitioned capsules which burst open when ready. Dispersal takes place directly around the plants and usually one finds the plants growing in clusters in fynbos.

Above: The eight hectares of the Diosma Reserve is flanked by suburbia, a patch of eucalyptus trees and veld. A proposed development planned for the near future may compromise its ecological integrity. It is the only property in the Mossel Bay district that the local municipality has agreed to conserve and manage.

Flanked by suburbia

This little buchu occurs in a very small area and grows ONLY in Heiderand, Mossel Bay. It is under severe threat due to its limited distribution, development, alien invasive species, poor management and non-inclusive planning – which contributes to its listing as Critically Endangered on the South African National Biodiversity Institute (SANBI) Red List. Eight hectares of fynbos have been set aside as a reserve for the species. But this Diosma Reserve is flanked by suburban homes, a church, a patch of invasive eucalyptus trees and a bit of veld.

The new population discovered early in May is nearby, on approximately 10 hectares in a beautiful meadow of fynbos. It is public property, zoned as Open Space II. The reserve and the new site can easily be (and should be) consolidated. Within the Mossel Bay district, the Diosma Reserve is the only property the municipality has undertaken to conserve formally.

Top: The rare and under threat endemic buchu, Diosma aristata, was found in this beautiful meadow of fynbos. The question now is: will planning decisionmakers allow for its survival or will it disappear under housing? Above: Rusty flowers of Elegia stipularis make for a photo stop with man’s best friend. Interim Garden Route Botsoc Chair, Dr Brendan Cole, came to see the new site where a population of the Critically Endangered Diosma aristata was recorded during the City Nature Challenge. This site can easily be combined into a greater ecological entity with the Diosma Reserve.

Our efforts to protect this species

On 7 June 2017, when the scary Knysna fire inferno started, a fire swept through this reserve as well. So there was huge relief when CapeNature, during its annual census of the species, found tiny little seedlings during their next count.

During this year’s census it was decided to explore ex situ cultivation options. BotSoc’s Conservation Manager Rupert Koopman put us in touch with the Kirstenbosch horticulturist and buchu expert, Roger Oliver. A posy of cuttings of the Diosma aristata (and some co-occurring buchu species) were delivered to him during May to plant off site.

Above: The Diosma Reserve is home to other species and creatures too, such as another buchu, Acmadenia heterophylla and a visiting Common Opal, Chrysoritis thysbe thysbe.

The ever-present threats

Rapid urban encroachment, edge- and island effects, indifferent town planning, lack of awareness and irreverent human abuse are the usual culprits. Rapid urbanisation is taking place in Mossel Bay, which is now a sought-after semigration destination.

There are, however, some actions being undertaken to protect the population. Clearing of alien invasive plants such as Rooikrans (Acacia cyclops) and Port Jacksons (Acacia saligna) by contractors take place from time to time. After the 2017 fire until lockdown, a collaboration of CapeNature, Outramps CREW (Custodians of Rare and Endangered Wildflowers) and the Fransmanshoek Conservancy rangers did regular hacks. The eradication requires urgent ongoing attention. Lately there is also unwelcome ingress of the neighbouring eucalypts.

Tipping of building rubble and garden refuse, rubbish and ‘skelms-on-scramblers’ prompted the municipality to curb access to the site, and as such they are now fencing the site sections at a time.

Above: Another buchu, Agathosma muirii, loved by the Cape honey bees, Apis mellifera ssp. capensis occur here. This buchu is one of the 14 red-listed plants in the Diosma Reserve. The SA Red List for Threatened Species gives its status as Vulnerable.

Development plans – why we’re worried

With natural veld in the vicinity, the little reserve has been able to function as an ecological entity until now. However, both the Diosma Reserve and the nearby new location fall within the intensification corridors to deliver on housing and business nodes and thus are in need of long-term protection.

There is pressure on the Mossel Bay Municipality to provide for the unprecedented demand for housing, but also actively manage the challenges of social issues and crime. In many instances open spaces, natural corridors and veld are perceived negatively by residents. The understanding of what biodiversity entails is just not present in the community either, which shows the need for engagement.

Left: Erica lasciva has four pointy bits on its stigma! It is one of the Ericas one sees in Heiderand, the suburb where Diosma aristata grows. Without the Diosma Reserve, Heiderand would soon just be a name and no longer reflect the abundance of Heide (Erica species) that once thrived in this suburb of Mossel Bay. Right: Erica pulchella – a demure beauty seen in both the Diosma Reserve and on the new Diosma site.

Why do we care

This conservation action is not only about preserving a single species: it’s about protecting habitats for a host of plants and creatures, many which we know and others we still don’t even know of. All of Mossel Bay’s natural areas are under severe threat and much has been lost already. This is a tragedy, as Mossel Bay’s vegetation is extremely diverse on a local level.

Had it not been for Diosma aristata there is no doubt that the fynbos would have disappeared under housing and golf estates long ago. The reserve is home to birds, ‘bokkies’, tortoises and many charismatic and unassuming plant species and 14 red-listed species have been recorded there.

This is OUR landscape and our veld, which is irreplaceable and should be a point of pride. There is a chance to make a globally significant green difference here, should we choose to.

Above: The delicate blue bells of Gladiolus rogersii is always a delight in spring.

Top: There are several Hermannia species in the Diosma Reserve and possibly three new undescribed species too. This is Hermannia flammula. The common name for Hermannias is doll’s rose or poprosie! Above: Hermannia saccifera is a very pretty ground cover flower. Cheerful when in flower it always makes one smile. So take a moment to kneel down and acknowledge its beauty by taking a photograph.

Sources:

– The Plight of Diosma aristata. Carlo van Tonder and AnneLise Schutte Vlok of Cape Nature. Presentation to Fynbos Forum 7-9 September 2021.

– Diosma Reserve’s 14 Red-Listed species

– PlantzAfrica

Above: Sandra Falanga, a BotSoc member and a member of the Outramps CREW group, delivered the cuttings of the Diosma aristata to Kirstenbosch horticulturist Roger Oliver. Top right: BotSoc’s Conservation Manager Rupert Koopman, who facilitated the communication between Sandra and Roger, joined them in May during the handover.