A Burning Question: Can Long-term Data Inform Fire Management in the Twenty-first Century? - Biodiversity Conservation and Environmental Change - page 66

will be needed to restore locally extinct species. For example, the palm ( Rhopalostyli sapida ),
the mistletoe Tupeia antarctica , and trees such as Dacrydium cupressinum , Aristotelia ser-
rata , Knightia excelsa , and Pseudowintera axillaris all persisted throughout the warmer con-
ditions of the MWP, and could survive in today's warming climate (Atkinson 2004, Wilmshurst
et al. 2013). Restoring podocarps, the main component of the coniferous, preanthopogenic
forest, may prove difficult, however, because soil composition may have been irreversibly
changed by forest clearance and subsequent enrichment by burrowing seabirds (Fukami
et al. 2006). Further challenges include the presence of alien plants, which outcompete native
flora and disrupt essential ecological processes like pollination (Wilmshurst et al. 2013).
Knowledge of landscape origins can dramatically affect management and conservation
targets, overturning assumptions and interpretations of present-day landscape patterns. It
has been argued, for example, that the entire island of Madagascar was forested and fire
free until the arrival of people about 2,000 years ago, but palaeoecological studies from
south-east Madagascar revealed a surprising history (Bond and Silander 2008, Willis et al.
2008, Virah-Sawmy et al. 2009a, b). The littoral forests of southeast Madagascar are among
the smallest and most diverse habitats in Madagascar and is confined to small isolated
patches, with high diversity and concentration of endemic (unique) species. These frag-
ments are are set in a matrix of fire-prone heathland, on a gently undulating landscape only
a few metres above sea level.
Though a top priority for conservation due to their limited extent, the littoral forests are
often perceived as doomed relics of a once extensive forest landscape. This interpretation has
been used to justify ilmenite mining in the remaining forest fragments. However, a multiproxy
palaeoecological approach from forest patches and the surrounding heathland matrix showed
contrasting vegetation histories. At one site, Mandena, the heathland was clearly of recent ori-
gin; about 1,500 years ago, closed forest had been replaced by grassland and ericaceous spe-
cies (Virah-Sawmy et al. 2009a) (Figure 4.4a). Evidence for fire at Mandena only occurred from
about 1,000 years ago, and was likely associated with human occupation. However, at the other
heathland site, St Luce, a unique, open woodland type with no modern analogue, was present
between 5,800 and 5,200 years ago, dominated by drought-sensitive species like Uapaca and
Symphonia . This woodland vegetation was replaced by ericoid grassland about 5,000 years
ago, predating the arrival of people by over 3,000 years. Furthermore, charcoal records show
that fire was present in both of these ecosystems, suggesting that fire was a natural part of
landscape dynamics (Figure 4.5b) (Virah-Sawmy et al. 2009a). The findings from St Luce are
helping to overturn the 'whole forest island' myth and degradation narrative that obscures
opportunities for conserving both heathlands and forest islands. The study also disproves the
idea that fire was introduced by people 2,000 years ago, and shows that fire-prone ericoid
grassland, which was previously thought to have been a degraded landscape resulting from
deforestation, is in fact a natural and legitimate part of the vegetation mosaic (Virah-Sawmy
et al. 2009a, b). This information could help to focus conservation attention on non-forested
habitats that are home to unique arrays of species that are adapted to openlands, as well as
incentivizing conservation of small forest islands, which are a long-standing and natural fea-
ture of the landscape (Bond and Silander 2008, Willis et al. 2008, Parr et al. 2014).