Title: Tradeoffs and synergies between ecosystem services, agrobiodiversity and agroforestry
1Tradeoffs and synergies between ecosystem
services, agrobiodiversity and agroforestry
African Regional Workshop on Sustainable Use of
Biological Diversity, UNON, 12-15 December 2006
2Agrobiodiversity includes all components of
biological diversity of relevance to food and
agriculture as well as the components of
biological diversity that constitute the
ecosystem the variety and variability of
animals, plants and micro-organisms, at the
genetic, species and ecosystem levels, which
sustain the functions, structure and processes of
the agro-ecosystem. including trees that are
part of the food system and all trees that play
roles in ecosystem function.
Agroforestry deliberately managed trees on
farms and in agricultural landscapes.
Ecosystem services benefits that people derive
from ecosystems, including provisioning services
(including food), regulating services, cultural
services and supporting services.
3Agroforestry is an example and driver of
agrobiodiversity at various scales plot
scale farm / household scale landscape or
ecosystem scale food system scale Dagmar
Mithoefer
43. Agroforestry, diversity of soil organisms,
food production services and effects on the water
cycle at the plot scale results from Sileshi
and Mafangoya Applied Soil Ecology 33 49-60
(2006)
Tephrosia candida fallow Nutrient Cycling by
Leaf Litter BNF Deep capture
5Kalunga site (on-farm)
Msekera site (on-station)
Beetles
Beetles
80
70
Earthworms
Earthworms
Ants
Ants
70
Millipedes
Millipedes
60
60
50
50
40
Number per square meter .
Number per square meter .
40
30
30
20
20
10
10
0
0
Acacia
Acacia
Gliricidia
Caliandra
Gliricidia
Caliandra
Leucaena
Leucaena
Pure maize
Pure maize
Maize grown in improved fallows harbours more
populations compared with monoculture maize
(Sileshi Mafongoya, 2006)
6Agroforestry and watershed function plot-level
results from Western Kenya
7Runoff Losses Yields
mm t/ha t/ha
95/98 CC w/o P 367 105a 1.1a
CC w/ P 255 43b 2.8b
IFr/C -P 325 80a 1.4a
IFr/C P 232 38b 2.9b
8Agroforestry systems have lower yield than maize
with fertilizer, but higher infiltration (esp on
station)
Site Treatment Infiltration (mm/min) Maize yield (t ha-1)
Msekera (on station) Pure maize 1.7b 4.3a
Gliricidia 2.0a 2.4a
Acacia 1.9a 2.4a
Leucaena 2.9a 2.1a
Caliandra 2.1a 1.5a
Kalunga Pure maize 3.6a 6.2 a
(on farm) Gliricidia 3.9a 4.3 b
Acacia 4.0a 2.6 c
Leucaena 3.8a 2.0 c
Caliandra 3.4 1.4 c
Adapted from Sileshi Mafongoya, 2006 Applied
Soil Ecology 33 49-60
9Carbon sequestration in the soil
- Soil C differed according to soil depth across
various species. - 60 100cm layer stored largest C.
- Species with higher storage Sesbania sesban, T.
candida, L. collinsi. - Most important factors in soil storage are
species, soil texture and depth.
10 ASB Partnership for the humid tropica forest
margins
11400
Primary Forest
300
Managed forest
Vegetation Carbon
200
Tree-based systems
(Mg ha-1)
100
Crops, Pastures, Grasslands
0
100
Soil Carbon
From ASB Climate Change Working Group,Palm et al.
12- Biodiversity Plot measurements in Bungo District,
Jambi - Saida and Gregoir Vincent, in prep
Total number of trees gt 15 cm DBH encountered
13Landscape and catchment scale relationships
1. Some evidence of biodiversity contributing to
regulating and cultural ecosystem services
2. Some evidence of biodiversity contributing to
productive services, particularly for the poor
and particularly in stress times (Dagmar
Mithoefer)
14Agroforestry and Biodiversity Conservation
- Agroforestry contributes to biodiversity
conservation through four major pathways - Reducing pressure on natural forests (Schroth et
al. 2004) - Providing habitat for native plant and animal
species, and (Schroth et al 2004) - Serving as a benign matrix land use for
fragmented landscapes (Schroth et al 2004) - Commercialization and deliberate management can
serve as a means of controlling historical
introductions of invasive tree species. (Mwangi
and Swallow)
15Improved fallows
Clearing
Miombo woodlands
Grass fallow
continuous cropping
Poor yields
NPK Fertilizer
Improved fallow
Improved yields
16Rotational Woodlots Acacia species yield approx
100t/ha after 5 years Reducing pressure from the
tobacco sector on miombo woodlands
17Agroforestry for habitat Shade coffee
Shade coffee supports diversity of avifauna in
the landscape.
18LIVE FENCES
Fencing is a major cause of deforestation in
drier areas.
Live fences are alternatives to dead fenceslimit
tree clearanceand are sources of income .
Jatropha
19Harvey et al. 2005
20Commercialization and deliberate management can
serve as a means of controlling historical
introductions of invasive tree species. (Mwangi
and Swallow)
21Mwangi Swallow, 2005
22Wrap-up Productive land uses are associated
with a wide range of ecosystems services, with
tree-based systems having potential for providing
ecosystem services intermediate between protected
areas and monocrop agriculture. Different
ecosystem services emerge at the landscape and
ecosystem levels requiring good understanding
of landscape dynamics. An agrobiodiversity
approach requires ecosystem analysis, as well as
food system analysis.