APPENDIX S3: Dryland Ecosystem Services
Introduction
Dryland livelihoods rely on dryland ecosystem goods and services, whose delivery is
fundamentally constrained by water scarcity thereby limiting primary productivity
and nutrient cycling and all deriving services [1, 2l].
Supporting Services in Drylands:
The low basal vegetation cover typically found in drylands contributes little biomass
to the overall small soil organic matter (SOM) pool [3]. It also favors wind and
laminar water erosion causing loss of SOM. Low SOM reduces soil fertility and the
soil’s potential to retain soil moisture and mineral nutrients in the soil solution (low
cation exchange capacity); this in turn triggers nutrient loss and a slowdown in soil
nutrient cycling resulting in low primary production and slow plant growth. Since
most global drylands are rangelands, most aboveground primary production that is
consumed by livestock is recycled as milk, meet, wool, feces and urine (figure 2).
Regulating Services in Drylands
Dryland soils play an important role in climate regulation. First, they are important
sinks of organic and inorganic carbon, thus, considering the wide global extension of
dryland ecosystems [1], they contribute substantially to mitigating regional and global
scale greenhouse gas effects on climate. Secondly, low or degraded vegetation cover
changes the local energy-water balance, ultimately leading to less precipitation [4]
(figure 2).
Cultural services in Drylands
Peoples living in different drylands around the world have established strong identity,
connections to and knowledge of their lands and resources. Examples include the
development of genuine traditional water conservation and appropriation techniques
[5]. Hence, when introducing new management technologies, infrastructure,
government programs (subsidies) or other incentives, or imposing new governance
structures or institutions, it is fundamental to consider and integrate existing cultural
connections to the land and the diversity of cultural services. Alternatively, it is
important to ensure that any of these changes considers the establishment and
cultivation of new connections between cultural values and innovations [6, 7] (figure
2).
Provisioning Services of Drylands
With an increasing loss in vegetation cover and infiltration of precipitation water (see
above), people retain and store run-off water in earthen ponds and dams. This spatial
redistribution of water favors livestock and agricultural production.
Current status of different ecosystem services in Amapola DSES
Provisioning Services - Pine oak forests dominated by Pinus cembroides provide fuel
wood, construction material and piñon (pine seeds) for household use in both farming
livelihood types and as rangeland for extensive livestock production. Piñon
production mast years are every five years. In those years, the inhabitants of Amapola
and many people from nearby San Luis Potosi collect seeds en masse, because they
sell well ($10 per kg) at local markets. Pine seed harvest, deforestation and seedling
herbivory on pine seedlings increasingly cause a decline in pine tree abundance
(figure 4; figure S4.1).
Secondary grasslands offer forage for livestock production. High stocking
rates have triggered severe land degradation and gully formation in this land cover
type in the alluvial fans. Agricultural land offers diverse annual cereals and vegetable
crops for farmer use and more recently for animal production. Abandoned croplands
have been increasingly used to raise livestock. Gullies originating in the upper parts
of the alluvial fans connect secondary grasslands with croplands which when
unplanted (nine months of the year) are highly vulnerable to erosion, exacerbating the
process of degradation and soil loss.
Amapola has eight surface wells, all located in communal lands and with open
access and use rights by all community members. This freshwater is used as drinking
water and for household use. However, a detailed analysis of water quality indicates
that, though none of them was naturally enriched with or contaminated by heavy
metals from mining activities, 90% of the wells were contaminated with pathogenic
microbes.
Between 1960 and 2006, 16 earthen dams were constructed in the Amapola
watershed area to enhance livestock production as drinking water for animals and
occasionally for crop forage production. The dams were established at the base of
gullies. According to detailed household surveys, 73% of the population perceive that
the water level of the surface wells has decreased over the last 10 years. This is
probably the consequence of an increase in runoff and a simultaneous decline in water
infiltration rates and groundwater recharge.
Supporting and regulating services - Regarding variables regulating hydrological
processes, soil depth in grasslands in the alluvial fans was only a third of the soil
depth in the forest on rocky substrate. Active croplands had the highest soil depth
with almost 0.5 m (Appendix S3; Table S3.2). Soil bulk density was significantly
higher in grasslands compared to forest soils, at both soil depths. In croplands the top
15 cm were more compacted than soil at 15-30 cm. Soil depth and soil compaction
affected water infiltration rate, which was three to four times greater in forest soils
compared to soils of grassland and abandoned agriculture. However, in active
agriculture plots, infiltration rate was almost twice as high as in forests (Appendix S3;
Table S3.2). Annual surface runoff was similar in forest and active agriculture sites;
however, it was two to three times higher in grasslands (Appendix S3; Table S3.2).
Table S3.1: Supporting ecosystem services: soil depth, soil organic matter (SOM),
soil organic carbon (SOC), total nitrogen and potential nitrogen mineralization (slow
variables) at two soil depths, associated with management and land use types in
Amapola, Sierra San Miguelito.
Land use
Soil depth
SOM
SOC
Total Nitrogen
Potential N
(cm)
(t/ha)
(t/ha)
(t/ha)
mineralization rate
(mg NH4+/kg soil/day)
Pine-Oak
Forest
Grassland
Crop land
Abandoned
crop land
0-15
92.3±0.8a
54.3±6.5ª
3.2±0.40ª
15-30
80.6±0.96b
55.7±4.7a
2.9±1.2ª
0-15
68.1±1.49c
13.7±0.94d
1.8±0.8d
15-30
46.4±1.33c
6.4±1.0e
1.0±0.5e
0-15
61.6±1.05c
18.0±2.0c
2.0±1.1c
15-30
51.3±0.93c
24.4±2.1b
2.1±0.3c
0-15
28.3±2.4b
2.5±0.9b
15-30
19.1±1.7c
2.1±0.2c
0.97±0.10
0.20±0.06
0.22±0.07
Different letters indicate statistical difference among values in a column at P<0.05
(Tukey test), n=5.
Table S3.2. Regulating services: soil and vegetation characteristics influencing
hydrological processes, associated with management and land use types in Amapola,
Sierra San Miguelito, Mexico.
Land use
Observed soil
depth (cm)
Soil bulk
density
Plant cover
(%)
(g/cm3)
Infiltration
rate
(mm/hr)
Total
annual
runoff
(mm)
Pine-Oak
Forest
34 b
Grassland
19 c
0.80 ± 0.1c
18.2±2.5a
350 ± 10.8b
33.4 b
7.2±3.5b
95 ± 6.9c
96.2 a
Seasonal
660 ± 15a
36.2 b
annuals
80 ± 2.4d
0.96±0.2 c
1.49±0.8 a
1.33±0.5 a
Crop land
49 a
1.05±0.3 b
0.93±0.12 c
Abandoned
crop land
24 c
Different letters indicate statistical difference among values in a column at P<0.05
(Tukey test), n=5.
Table S3.3. Supporting and regulating services in two cropland types (subsidy, nosubsidy): soil depth, soil organic matter (SOM), soil organic carbon (SOC), total
nitrogen, soil bulk density and potential nitrogen mineralization rate observed at two
soil depths related to different crop management types (with and without subsidy).
Land use
Soil depth
(cm)
SOM (t/ha)
SOC
(t/ha)
Total
Nitrogen
(t/ha)
Soil bulk
density
(g/cm3)
Subsidy
0-15
3.1 ± 0.9b
23.2±2.1a
1.9±1.3a
1.3±0.2a
agriculture
15-30
3.0 ± 0.8b
13.5±2.9b
1.5±0.4b
1.1±0.1b
No subsidy
0-15
4.2 ± 1.2a
25.5±1.7a
2.6±0.9a
1.0±0.5b
agriculture
15-30
3.6 ± 0.9a
22.4±3.1a
2.0±0.2a
0.9±0.2b
Potential N
mineralization
rate
(mg NH4+/kg
soil/day)
25.4±0.6b
41.2±1.1a
Different letters among values in a column indicate statistical difference at P<0.05 (Tukey
test), n=5.
REFERENCES APPENDIX S3
[1] Safreil, U. Adeel, Z. Niemeijer, D. Puigdefabregas, J. White, R. Lal, R. Winslow, M. Ziedler,
J. Prince, S. Archer, E. & King, C. 2005 Dryland systems. In Ecosystems and human well-being:
current state and trends (ed. R. Hassan, R. Scholes, N. Ash) Millenium Ecosystem
Assessment, pp. 623-662. Island Press. Washington, D.C.
[2] Dougill, A. J. Lindsay, C. Stringer, J. L. Riddell, M. Rueff, H. Dominick, V. S. & Butt,
E. Lessons from Community-based payment for ecosystem service schemes: from forest
to grasslands. Phil. Trans. R. Soc. B, this issue.
[3] Lal, R. 2001 Soil carbon sequestration impacts on global climate change and food
security. Science 304, 1623-1627.
[4] Bonan, G. B. 2008 Ecological climatology: principles and applications. 2nd edition.
Cambridge University Press.
[5] Food and Agriculture Organization (FAO). 2009 Livestock keepers – guardians of
biodiversity. Animal Production and Health Paper. No. 167. Rome
[6] Chapin III, F. S., Folke, C. & Kofinas, G. P. 2009 A framework for understanding change. In
Principles of ecosystem stewardship (ed. F.S. Chapin, III, Kofinas, G.P. & Folke, C.), pp 3-28.
Springer, New York, N.Y.
[7] Berkes, F. Kofinas, G. O. & Stuart Chapin, F.S. III. 2009 Conservation, community, and
livelihoods: sustaining, renewing, and adapting cultural connections to the land. In Principles
of Ecosystem Stewardship (ed. F.S. Chapin III, G.P. Kofinas, C. Folke,), pp 129-147. Springer,
New York, N.Y.