Tradeoffs between income, biodiversity, and ecosystem functioning during tropical rainforest conversion and agroforestry intensification.
Losses of biodiversity and ecosystem functioning due to rainforest destruction and agricultural intensification are prime concerns for science and society alike. Potentially, ecosystems show nonlinear responses to land-use intensification that would open management options with limited ecological losses but satisfying economic gains. However, multidisciplinary studies to quantify ecological losses and socioeconomic tradeoffs under different management options are rare. Here, we evaluate opposing land use strategies in cacao agroforestry in Sulawesi, Indonesia, by using data on species richness of nine plant and animal taxa, six related ecosystem functions, and on socioeconomic drivers of agroforestry expansion. Expansion of cacao cultivation by 230% in the last two decades was triggered not only by economic market mechanisms, but also by rarely considered cultural factors. Transformation from near-primary forest to agroforestry had little effect on overall species richness, but reduced plant biomass and carbon storage by approximately 75% and species richness of forest-using species by approximately 60%. In contrast, increased land use intensity in cacao agroforestry, coupled with a reduction in shade tree cover from 80% to 40%, caused only minor quantitative changes in biodiversity and maintained high levels of ecosystem functioning while doubling farmers' net income. However, unshaded systems further increased income by approximately 40%, implying that current economic incentives and cultural preferences for new intensification practices put shaded systems at risk. We conclude that low-shade agroforestry provides the best available compromise between economic forces and ecological needs. Certification schemes for shade-grown crops may provide a market-based mechanism to slow down current intensification trends.
Steffan-Dewenter
Ingolf
I
Department of Agroecology, Georg-August-Universität Göttingen, Waldweg 26, 37073 Göttingen, Germany.
Kessler
Michael
M
Barkmann
Jan
J
Bos
Merijn M
MM
Buchori
Damayanti
D
Erasmi
Stefan
S
Faust
Heiko
H
Gerold
Gerhard
G
Glenk
Klaus
K
Gradstein
S Robbert
SR
Guhardja
Edi
E
Harteveld
Marieke
M
Hertel
Dietrich
D
Höhn
Patrick
P
Kappas
Martin
M
Köhler
Stefan
S
Leuschner
Christoph
C
Maertens
Miet
M
Marggraf
Rainer
R
Migge-Kleian
Sonja
S
Mogea
Johanis
J
Pitopang
Ramadhaniel
R
Schaefer
Matthias
M
Schwarze
Stefan
S
Sporn
Simone G
SG
Steingrebe
Andrea
A
Tjitrosoedirdjo
Sri S
SS
Tjitrosoemito
Soekisman
S
Twele
André
A
Weber
Robert
R
Woltmann
Lars
L
Zeller
Manfred
M
Tscharntke
Teja
T
D000383:Agriculture; D000818:Animals; D044822:Biodiversity; D002099:Cacao; D016468:Forestry; D007182:Income; D007313:Insecta; D018515:Plant Leaves / Q000502:physiology; D013045:Species Specificity; D014197:Trees / Q000502:physiology*; D014329:Tropical Climate