THE BIG PICTURE

Tracking flora up a Madagascan massif

RALPH CLARK & ANDRINAJORO RAKOTOARIVELO visited the little-known Ankaratra massif to assess its potential as a test site to monitor Madagascar’s response to man-made threats, from deforestation and fire to invasive plants and climate change

PHOTOS BY ANDRINAJORO RAKOTOARIVELO

Tracking flora up a Madagascan massif

RALPH CLARK & ANDRINAJORO RAKOTOARIVELO visited the little-known Ankaratra massif to assess its potential as a test site to monitor Madagascar’s response to man-made threats, from deforestation and fire to invasive plants and climate change

PHOTOS BY ANDRINAJORO RAKOTOARIVELO
This all-in-one panorama of a section of the Ankaratra massif and its challenges, from about 2 200 metres, looks towards a small peak at 2 406 metres, with Tsiafajavona (2 643 metres) in the distance on the left.

 

Spectacular evenings amid the calls of Madagascar nightjars and starry views north towards the island’s capital Antananarivo are some of the more relaxed memories that we brought home with us from our trip to assess Ankaratra, a little-known extinct volcanic massif. It lies some 50 kilometres south west of Madagascar’s capital, Antananarivo, along the island’s north-south highland spine and just 17 kilometres away from the nearest small town, Ambatolampy.

The rolling hills around the base of Ankaratra reach about 1 500 to 1 600 metres high. We climbed up to about 2 000 metres and camped at what could have been the traditional site of the legend where, two or three centuries ago, a lovesick young man from the island’s lowland eastern forests planted a forest in exchange for the hand of the local princess. His chosen trees were the indigenous Weinmannia bojeriana (Cunoniaceae) trees – not too dissimilar from our southern African red alder (Cunonia capensis) or butterspoon tree.

It was a charming thought but locality information about the area of our campsite was, unfortunately, conflicting. We might not have been at the lovers’ grove, after all. Even if we were, it seems that the suitor’s forest had succumbed to the charcoal burners.

Left: Our days in camp at Ankaratra started early to make the most of our time for field work. Right: Weinmannia bojeriana (Cunoniaceae) is a common forest margin species at Anosiarivo forest on Ankaratra massif. Legend has it that a grove of these trees was planted by the suitor of a princess. Unfortunately, now the grove has been turned into charcoal. Only scattered shrubs were left in an open grassland where we camped. Photo by Ralph Clark

 

ON A KNIFE-EDGE

Only a few straggly weinmannia were left hanging on along the (now) grassy ridge where we camped. Fortunately, the nearby bulk of the Anosiarivo forest is still largely intact.

One estimate suggests that only a tenth of Madagascar’s original forests remain intact. The ancient practice of slash-and-burn agriculture, known here as tavy, and charcoal burning for fuel and profit have taken a heavy toll.

As part of the Afromontane Research Network’s regional partnership building for southern African mountain research, we were here to work with the Malagasy ecology research organisation, Association Vahatra. We would be assessing Ankaratra as part of looking for sustainable solutions for Malagasy high-elevation ecological systems.

Ankaratra is an emotional roller-coaster, perhaps representing much of the modern tragedy of Madagascar. Standing on a knife-edge ridge at 2 200 metres, on one side you gaze on intact montane forest with Madagascar cuckoo-rollers careering loudly over it. On the other side are smouldering charcoal pits in a devastated landscape that was the same intact forest not many months ago.

The emotional roller-coaster gets more complicated in the heathland, where the charcoal burners have done the favour of removing all the invasive patula pines. But the unmanaged fires have also reduced the original heath cloud-forest to resprouting remnants.

Meet our Ankaratra team, from left to right: Ralph Clark (Afromontane Research Unit), Ingahy Rafenomanana (Vondrona Ivon’ny Fampandrosoana) and Joro Rakotoarivelo (Afromontane Research Unit).

 

SIZING UP ANKARATRA

Ankaratra tops out at 2 643 metres, with its peak called Tsiafajavona, Malagasy for ‘never out of the mist’.

There are only two other higher massifs in Madagascar. Tsaratanana peaks with the volcano Maromokotro reaching the highest point in the island, 2 876 metres. Imarivolanitra or Pic Boby in the Andringitra massif is the island’s second-highest mountain at 2 658 metres.

Ankaratra is also higher than some of the highest national peaks in southern Africa, including:

Angola: Morro do Moco, 2 620 metres
Zimbabwe: Mount Nyangani, 2 592 metres
Namibia: Brandberg, 2 573 metres
Mozambique: Monte Binga, 2 440 metres

The area of the Ankaratra massif is 5 200 square kilometres, rather smaller than the Great Winterberg–Amathole in the Eastern Cape, for instance, at around 7 000 square kilometres. Only about 8 130 hectares (1.6%) is theoretically protected in the form of Manjakatompo Ankaratra Natural Resource Reserve. In turn, this is theoretically managed by the community group Vondrona Ivon’ny Fampandrosoana (VIF) but it is visibly lacking in capacity and resources.

We were guided by Ingahy Rafenomanana, also known as Dadafara, the local VIF representative, who has a deep historical lived experience in the area. He was an excellent guide and provided fascinating background contextual information on the area. Association Vahatra kindly arranged for us to use a vehicle and camping equipment and to enjoy amazing meals of rice and tilapia on the mountain prepared by Ledada.

IMMEDIATE CHALLENGES

Ankaratra, with its sinuous ridges radiating out from a central point like a starfish, represents a classic Afro-Malagasy socio-ecological challenge. Most of the indigenous evergreen forests that grow at altitudes between 1 600 and 2 000 metres have been turned into charcoal.

The largest remaining patch, Anosiarivo forest, south of the ridge on which we camped, looks likely to go that way, too. There was charcoal burning activity from 1 600 metres right up to 2 300 metres while we were there.

In fact, there is also ongoing debate about how woody Madagascar was historically. It is interesting to note that during his visit in 1888 to 1889, British botanist G.F. Scott Elliot (1862–1934) recorded forest occurring only in sheltered valleys and not being found everywhere in the mountainous area.

At an altitude of 1 600 to 2 000 metres, Anosiarivo forest is a high-elevation, Malagasy montane forest with elements typical, or very similar to Afromontane forest, together with completely unique Malagasy components. Photo by Ralph Clark

 

AT HOME IN THE FOREST

Although Anosiarivo forest is considered low in species compared to others in Madagascar, it is a rich high-elevation Malagasy version of Afromontane or Afro-temperate forest. Familiar features include a plectranthus ground-storey and tree-friends such as African holly (Ilex mitis).

 

Local Malagasy montane versions of ‘mainland familiars’ include:

  • The canopy-dominant Dicoryphe stipulacea, closely related in the sub-tribe Dicorypheae (Hamamelidaceae) to our local ‘underbush’ forest genus Trichocladus, the honeysuckle tree or rooihout
  • Malagasy tree-fuchsia (Halleria ligustrifolia)
  • Boxwood (possibly Myrsine mocquerysii)
  • Razafimandimbisonia minor – at some point Razafimandimbisonia was taxonomically separated from Alberta, and R. minor superficially resembles our Natal flame bush (Alberta magna).

Epiphytes are abundant, including mosses, ferns, and orchids. They include the two-rowed oberonia (Oberonia disticha), an orchid which is widespread in tropical Africa and the Indian Ocean islands but known in only one locality in South Africa – the Wolkberg in Limpopo. Despite the familiar links, there are many species that it would take us some time to get to know.

Top: This isolated fragment of Malagasy montane forest north of Anosiarivo forest has so far escaped the charcoal burning that has consumed most of the forest around it.  Bottom: We recorded this flowering Razafimandimbisonia minor tree on the edge of Anosiarivo forest at an altitude of 2 100 metres on the Ankaratra massif. It is widespread in mid to higher elevations in Madagascar and somewhat resembles the Natal flame bush.

ON THE WING

Although the resonating cry of the Madagascar cuckoo-roller replaces that of the mainland sombre bulbul or crowned hornbill, the general feel of Ankaratra is very much like mainland Africa – home from home.

Apart from the riveting cuckoo-rollers, and although there is a reasonable bird list of 69 species, the forest was not overly diverse in birds during our visit.

The spectacular Madagascar blue pigeons were a treat, however. Common newtonia was around and Madagascar brush warblers stalked us with their grating alarm call from the burnt margins. Madagascar bulbuls and Madagascar white-eyes were everywhere.

DEVASTATED: This erica-dominated heathland is found at an altitude of 2 200 metres or more on the Ankaratra massif. Heathland with shrubs and trees probably occurred in a zone between 2 200 and 2 400 metres high, lying between the montane forest and the sub-alpine moorland. It would likely have acted as cloud-forest as on other tropical African and western Indian ocean island mountains above 2 000 metres high.

RECOVERING: Heathland elements, including treelike erica, can be seen recovering from fire, at around 2 200 metres high on the Ankaratra massif. Ankaratra hosts at least five erica species, including a local endemic, E. bosseri , that grows at altitudes between 1 500 and 2 000 metres. Also seen in this picture are the sphagnum moss ground-storey and the non-indigenous sheep’s sorrel. 

HEATHLAND IN TROUBLE

Above the forest, from an altitude of 2 200 metres to about 2 400 metres, there was once extensive treelike heathland, perhaps two to four metres tall. It brought to mind the tall heathlands of Mount Karthala on Grande Comoro and Mount Elgon in Uganda.

A belt of heathland is typical of tropical African and western Indian ocean island mountains above 2 000 metres. It can be part of the transition between ecosystems (ecotonal) or have an identity (physiognomy) of its own between moist montane forest and moorland.

On Ankaratra, the individual species elements still seem to be present, including heath (Erica), bog moss (Sphagnum), hard fern (Blechnum), as well as some lucky tree fern (Cyathea). But the ecological structure has been devastated by annual uncontrolled fires.

Among the plants growing in the heathland zone at Ankaratra at about 2 300 metres above sea level, we recorded this geranium (probably G. arabicum), two erica species and a blechnum fern. 

BENEFITS OF FIRE FIGHTING

However, if fire is removed for a few years, it is very likely the heathland would bounce back quite quickly on its own, given the evidence of resprouting that we saw. This represents a low hanging fruit for any ecological restoration group who wants to do the right thing when it comes to woody restoration.

In fact, many conservation challenges in Madagascar could be solved through effective seasonal fire management. Allowing the heathland to recover would probably help reactivate a ‘cloud forest’ function that would recharge groundwater and increase the area’s water security.

HEATH & MOOR

Familiar flowering faces hanging on in the heathland include local species of dissotis, geranium and impatiens. But this landscape’s disturbed nature showed up in plants growing on waste land (ruderals) that were not indigenous, such as flatweed (Hypochaeris radicata) and sheep’s sorrel (Rumex acetosella). Malagasy stonechat, Madagascar mannikin and Madagascar fody were evident in these open areas, with Madagascar kestrel and yellow-billed kite around and about in the air.

Above the heath zone, from about 2 400 metres, is a mosaic of extensive sub-alpine moorland and stunted heathland. The relatively few references scattered in the literature suggest that this is rich in local endemic forbs, especially helichrysum, as well as several species from the umbellifers (Apiaceae), mints (Lamiaceae), mallows (Malvaceae) and grasses (Poaceae). Also listed were two endemic red-hot pokers (Kniphofia ankaratrensis and K. pallidiflora).

This moorland – on the highest reaches of the Ankaratra massif, above an altitude of 2 400 metres – has a high incidence of both endemic plants and animals. Intact heathland can also be seen at the bottom of the image and a fragment of montane forest at the lower left. The peak Tsiafajavona (2 643 metres) is the highest bump in the distance on the left.

RIPE FOR REDISCOVERY?

Back in 1927, the French botanist Joseph Perrier de la Bâthie (1873–1958), who specialised in Madagascan plants, listed about 30 endemics for the massif as a whole. This is comparable to endemism on SA’s Great Winterberg–Amathole.

But the question is are they still there? Six of the plants on Perrier de la Bâthie’s list are apparently still known only from the original collections deposited in herbaria which were designated type specimens and used to describe the species.

DRY SEASON

At least historically, ground orchids were abundant and diverse in this area. We were visiting during the dry season and it would be interesting to see what a summer visit would yield in this habitat today.
Visiting in the dry season also meant that it was difficult to tell what ecological condition the moorland was in and how it compares to an ‘original state’. That ‘original state’ is probably comparable in ecology and structure to high-elevation moorlands elsewhere in the Malagasy Afromontane region, especially considering G.F. Scott Elliot’s notes of profusions of wildflowers from his 1888–1889 visit.

Charcoal burning is the greatest threat to the social and ecological stability of the Ankaratra massif – this charcoal-burning pit was in the heathland zone just above the forest zone, at an altitude around 2 200 metres on Ankaratra.

UNDER PRESSURE

We saw signs of both fire and grazing by livestock during our visit. Poorly managed fire and grazing may be putting Ankaratra’s moorlands under pressure.

These moorlands are almost certainly a natural vegetation formation on these mountains rather than a result of deforestation, for example, and occasional fire is probably a natural phenomenon in the moorland. But sustainable rangeland and fire management would be necessary to maintain healthy grass cover, local endemic plant and animal populations, carbon stocks and optimal water catchment.

Our observations, supported by Google Earth images, indicate extensive bare ground and possible soil erosion in this zone. There was also perhaps some local cultivation up as high as 2 600 metres on Ankaratra’s western flanks that was reminiscent of seed potato cultivation in the Nyanga community lands on the slopes of Mount Rukotso in Zimbabwe. Some ‘familiar friends’ noted included lady’s mantle (Alchemilla), a very typical genus in high-elevation systems in Africa.

The end of another busy day’s field work and evening falls over our mountain camp on the Ankaratra massif. 

INVASIVE COCKTAIL

You don’t usually travel to Madagascar to see invasive species – but we were so struck by the similarity between the invasive cocktail on Ankaratra and along the eastern portion of southern Africa’s great escarpment that we could not ignore it.

On Ankaratra, we saw Australian acacias – including silver wattle (Acacia dealbata), black wattle (A. mearnsii) and Australian blackwood (A. melanoxylon) – up to elevations of about 2 000 metres. They typically grow in disturbed areas and along roads and are plantation escapees.

Mexican patula pine (Pinus patula), another plantation escapee, is well distributed at all elevations. We saw trees as high up as 2 400 metres.

Bugweed (Solanum mauritianum) is common along streams, in forest clearings and on forest edges. We even found some St Joseph’s lilies (Lilium formosanum) along the edges of Anosiarivo forest. Although a pretty plant, it is a poor replacement for the historical lover’s effort in planting the weinmannia grove.

At 2 000 m near Anosiarivo forest on the Ankaratra massif, we spotted this St Joseph’s lily, already an invasive species in South Africa – so it might also become a problem in higher elevations of Madagascar.

SUCCESSION WATCH

Looking ahead, we believe succession studies on Ankaratra would be very interesting – with the ericas providing the greatest conundrum. Within a matrix of dense erica thicket from 1 600 right up to 2 000 metres, natural forest regeneration is evident at various elevations where pressure has been removed for some time.

It is not clear if this is the same treelike erica species as in the heathland. In fact, there seem to be numerous erica species on Ankaratra including E. bosseri, which is endemic at lower elevations. Other ericas occurring on Ankaratra include E. macrocalyx, E. madagascariensis, E. minutiflora (for which Ankaratra is the type locality) and E. perhispida. This again suggests an original mosaic of vegetation in the montane belt and not just blanket forest.

But it would be interesting to test succession processes and what impact the erica’s fire-resistant (pyrophytic) qualities might have in the montane forest belt. The same applies to regeneration and succession of indigenous forest with and without invasive species as nursery plants.

KEEPING COUNT

Population censuses of endemic fauna and flora associated with the current vegetation conditions would be valuable. A large proportion of plant endemics, for instance, live in areas free of tree cover (open habitat). Ankaratra’s locally endemic amphibians, reptiles and invertebrates occur in forest, heathland or moorland, depending on elevation as well as vegetation types.

The contradictions and challenges of Ankaratra make for a fascinating laboratory of research and comparison with mainland African massifs under global change pressures. We hope to return soon!

Ralph Clark (clarkvr@ufs.ac.za) & Andrinajoro Rakotoarivelo are both part of the Afromontane Research Unit & UFS-QQ Risk & Vulnerability Science Centre, University of the Free State: QwaQwa Campus, South Africa. They also thank Sylvie Andriambololonera of Missouri Botanical Gardens for plant identification support.

The research exchange with Association Vahatra and Andrinajoro Rakotoarivelo’s research contract was supported by the UFS-QQ Risk & Vulnerability Science Centre, through NRF grant no.128386 to Ralph Clark as a South-South Global Change partnership.

The memorable evening view, looking west from our campsite on the Ankaratra massif – we hope to be back to continue our study of the pressures on Madagascar’s environment. 

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