It has to…. Forested area suitable for oil palm cultivation There is strong overlapArea (,000 km2) 2,500 2,000 1,500 between land suitable for 1,000 500 0 oil palm cultivation & r il C ia u ia la ia ia G n n ar s o e a a r m es d az DR es Pe r b ue ys liv PN roo bo m ao ng am a n ian a do na pin ilan a a n L o in uy u u e t lli a tropical forests B , on o m z la o e o d ol Ven Ma B m G My C ur G G c i i h E V Ph T ong In C C a S ch C en Fr Country Tropical land area suitable for oil palm Reference: ‘Woods Hole Research Center (2007) Readiness for REDD: A preliminary global assessment of tropical forested land suitability for agriculture’.
To what extent is this possible?• Which species?• At what spatial scale? – Within an oil palm monoculture? – Within an oil palm concession? – Within a landscape dominated by oil palm?• On what time scale?• How can we influence this through management?
Biodiversity value of oil palm monoculture Reference: Foster et al In press
Biodiversity value of oil palm monoculture‘Across all taxa, a mean of only 15% of species recorded in primary forest were also found in oil palm plantations’ Reference: Fitzherbert et al (2008), TREE 23: 538-45.
How are different species affected?• Medium to large mammals – 10% regularly entered the oil palm monoculture (Maddox et al. 2007)• Small mammals – Forest primates, squirrels & tree shrews were absent in oil palm (Danielsen et al 1995) – Bat species richness was significantly lower in the oil palm (Fukuda et al 2009)• Birds – Between 5 – 53% forest bird species were also present in oil palm (Danielsen et al. 1995; Aratrakorn et al. 2006; Sheldon et al. 2010)• Invertebrates – Fewer beetle, ant & moth species in the oil palm plantations (Chung et al. 2000, Chey 2006; Brühl et al. 2009; Fayle et al. In press) – Higher numbers of bee species (Liow et al. 2001)
Which species can survive in oil palmmonoculture? WINNERS LOSERS•Non-forest species •Forest species•General habitat requirements •Specific habitat requirements•Lower Conservation Concern •Higher Conservation Concern•High Abundance •Absent or reduced abundance•Eg. Pests, invasive species •Eg. Critically Endangered species
Can we make oil palm monoculture morehospitable for biodiversity? • Epiphytic birds nest ferns support similar numbers pf ant species in oil palm and primary forest, despite ant species richness being much lower in the canopy (52% loss) and leaf litter (74% loss). – Could help to increase ant species richness by 15%, but few forest species – Increase insectivorous birds? (Fayle et al 2010) •Birds – epiphytic ferns & leguminous ground cover •Butterflies – weed cover •Natural forest cover remaining had a bigger influence over bird & butterfly diversity (Koh et al 2008)
Biodiversity within oil palm concessions• Concession area = 10,216 ha• Mature oil palm• Conservation area = 980 ha• Approx 7km from a National Park 215 species, including 49 HCV species 120 HCV Species 100 Non-HCV Species Number of Species 80 60 40 20 0 Birds Mammals Amphibians Reptiles Taxon
Biodiversity value of forest fragments Ecological theory predicts:• Smaller, more isolated fragments = fewer species, smaller populations• A Single Large reserve will support more species than Several Small (SLOSS) Why? Smaller fragments = – Greater exposure to edge effects – reduce habitat quality – Less habitat available, fewer niches – Higher chance of local extinction due to random events Isolated fragments = – Lower chance of immigration to ‘rescue’ populations from extinction
Effect of fragment area •Species & genetic diversity decreased with fragment size •Fragment size required to retain equivalent diversity to contiguous forest = >650ha (all species), 2,500ha (forest specialists), 10,000ha (genetic) (Struebig et al in press)•Species richness & diversity, decreased with fragment size•Genetic diversity of 1 butterfly species was not affected by fragment size•Fragment size required to support island endemics = 4,000ha•Some species were only recorded in the smaller fragments (Bickel et al 2006, Bickel et al 2007) •Small fragments (0.7ha – 8.7ha) supported fewer species & lower abundances of birds than contiguous forest, particularly species of conservation priority. •Species composition in fragments more similar to oil palm than contiguous forest. (Edwards et al 2010)
Effect of fragment isolation• Does distance between fragments predict diversity? – Butterflies = reduced species & genetic diversity – Bats = no effect on species or genetic diversity• Depends on the ability of different species to move through the oil palm matrix• Maintaining connectivity could be critical to ability to persist over the long term
The value of Large vs Small areas of habitat Land sharing Land sparing Large Small •Higher diversity & bigger •Contribute to landscape level populations diversity •No changes in species •Still support some HCV species composition - supports HCV •Promote landscape level species connectivity •More resilient over time •Several small patches support higher diversity than a single large for some species
How can we ensure oil palm & biodiversitycan co-exist? • Avoid the conversion & fragmentation of large contiguous areas of natural habitat • Retain key fragments of habitat within the oil palm matrix • Increase habitat complexity of oil palm crop
Why must oil palm & biodiversity co-exist? "To keep every cog and wheel is the first precaution of intelligent tinkering.“ - Aldo Leopold