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Spatial planning for a green economy: National-level hydrologic ecosystem services priority areas for Gabon

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Rapidly developing countries contain both the bulk of intact natural areas and biodiversity, and the greatest untapped natural resource stocks, placing them at the forefront of “green” economic development opportunities. However, most lack scientific tools to create development plans that account for biodiversity and ecosystem services, diminishing the real potential to be sustainable. Existing methods focus on biodiversity and carbon priority areas across large geographies (e.g., countries, states/provinces), leaving out essential services associated with water supplies, among others. These hydrologic ecosystem services (HES) are especially absent from methods applied at large geographies and in data-limited contexts. Here, we present a novel, spatially explicit, and relatively simple methodology to identify countrywide HES priority areas. We applied our methodology to the Gabonese Republic, a country undergoing a major economic transformation under a governmental commitment to balance conservation and development goals. We present the first national-scale maps of HES priority areas across Gabon for erosion control, nutrient retention, and groundwater recharge. Priority sub-watersheds covered 44% of the country’s extent. Only 3% of the country was identified as a priority area for all HES simultaneously, highlighting the need to conserve different areas for each different hydrologic service. While spatial tradeoffs occur amongst HES, we identified synergies with two other conservation values, given that 66% of HES priority areas intersect regions of above average area-weighted (by sub-watersheds) total forest carbon stocks and 38% intersect with terrestrial national parks. Considering implications for development, we identified HES priority areas overlapping current or proposed major roads, forestry concessions, and active mining concessions, highlighting the need for proactive planning for avoidance areas and compensatory offsets to mitigate potential conflicts. Collectively, our results provide insight into strategies to protect HES as part of Gabon’s development strategy, while providing a replicable methodology for application to new scales, geographies, and policy contexts.
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RESEARCH ARTICLE
Spatial planning for a green economy:
National-level hydrologic ecosystem services
priority areas for Gabon
Joshua Howard Goldstein
1
*, Heather Tallis
2
, Aaron Cole
3
, Steven Schill
4
, Erik Martin
5
,
Michael Heiner
6
, Marie-Claire Paiz
7
, Allison Aldous
8
, Colin Apse
9
, Barry Nickel
3
1Office of the Chief Scientist, The Nature Conservancy, Fort Collins, Colorado, United States of America,
2Office of the Chief Scientist, The Nature Conservancy, Santa Cruz, California, United States of America,
3Center for Integrated Spatial Research, University of California-Santa Cruz, Santa Cruz, California, United
States of America, 4Caribbean Program, The Nature Conservancy, Provo, Utah, United States of America,
5Eastern Conservation Team, The Nature Conservancy, Brunswick, Maine, United States of America,
6Development by Design, The Nature Conservancy, Fort Collins, Colorado, United States of America,
7Gabon Country Program, The Nature Conservancy, Libreville, Gabon, 8Oregon Program, The Nature
Conservancy, Portland, Oregon, United States of America, 9Africa Program, The Nature Conservancy,
Portland, Maine, United States of America
*jgoldstein@tnc.org
Abstract
Rapidly developing countries contain both the bulk of intact natural areas and biodiversity,
and the greatest untapped natural resource stocks, placing them at the forefront of “green”
economic development opportunities. However, most lack scientific tools to create develop-
ment plans that account for biodiversity and ecosystem services, diminishing the real poten-
tial to be sustainable. Existing methods focus on biodiversity and carbon priority areas
across large geographies (e.g., countries, states/provinces), leaving out essential services
associated with water supplies, among others. These hydrologic ecosystem services (HES)
are especially absent from methods applied at large geographies and in data-limited con-
texts. Here, we present a novel, spatially explicit, and relatively simple methodology to iden-
tify countrywide HES priority areas. We applied our methodology to the Gabonese Republic,
a country undergoing a major economic transformation under a governmental commitment
to balance conservation and development goals. We present the first national-scale maps of
HES priority areas across Gabon for erosion control, nutrient retention, and groundwater
recharge. Priority sub-watersheds covered 44% of the country’s extent. Only 3% of the
country was identified as a priority area for all HES simultaneously, highlighting the need to
conserve different areas for each different hydrologic service. While spatial tradeoffs occur
amongst HES, we identified synergies with two other conservation values, given that 66% of
HES priority areas intersect regions of above average area-weighted (by sub-watersheds)
total forest carbon stocks and 38% intersect with terrestrial national parks. Considering
implications for development, we identified HES priority areas overlapping current or pro-
posed major roads, forestry concessions, and active mining concessions, highlighting the
need for proactive planning for avoidance areas and compensatory offsets to mitigate
potential conflicts. Collectively, our results provide insight into strategies to protect HES as
PLOS ONE | https://doi.org/10.1371/journal.pone.0179008 June 8, 2017 1 / 21
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OPEN ACCESS
Citation: Goldstein JH, Tallis H, Cole A, Schill S,
Martin E, Heiner M, et al. (2017) Spatial planning
for a green economy: National-level hydrologic
ecosystem services priority areas for Gabon. PLoS
ONE 12(6): e0179008. https://doi.org/10.1371/
journal.pone.0179008
Editor: Judi Hewitt, University of Waikato, NEW
ZEALAND
Received: November 25, 2015
Accepted: May 23, 2017
Published: June 8, 2017
Copyright: ©2017 Goldstein et al. This is an open
access article distributed under the terms of the
Creative Commons Attribution License, which
permits unrestricted use, distribution, and
reproduction in any medium, provided the original
author and source are credited.
Data Availability Statement: The data for this
research are available from Figshare at: https://doi.
org/10.6084/m9.figshare.4986212.v1.
Funding: Funding was provided by the Anne Ray
Charitable Trust. The funder had no role in study
design, data collection and analysis, decision to
publish, or preparation of the manuscript. The
authors are not aware of any competing interests
on the part of the funder.
Competing interests: The authors have declared
that no competing interests exist.
part of Gabon’s development strategy, while providing a replicable methodology for applica-
tion to new scales, geographies, and policy contexts.
Introduction
As the global population approaches 9 billion people or more, major investments in infrastruc-
ture, energy, agriculture, and other sectors are projected to occur in the coming decades [1].
Where these investments occur and how they are operated will impact biodiversity and the
benefits nature provides to people, called ecosystem services [24]. A key global challenge fac-
ing society is how to achieve development goals while protecting the planet’s biodiversity and
human life-support systems [58].
To address this challenge, new science and policy approaches are emerging that integrate
conservation values into sustainable or “green” economic development pathways (e.g., [4,9,
10]). However, practice lags behind rhetoric, and key gaps remain in methods to identify and
create development plans that avoid sensitive biodiversity and ecosystem-service areas and
alter development activities for minimal impact [11].
Methods to identify priority areas for biodiversity across large geographies (e.g., countries,
states/provinces) have improved substantially over the past decade (e.g., [12,13]) and have
found increasing, but still slow uptake in development decisions (e.g., [9,14,15]). Similarly,
technological advances have enabled large area, high-resolution mapping of carbon stocks
related to global climate regulation (e.g., [16,17]).
Despite these advances, methods to identify priority areas across large geographies for
hydrologic ecosystem services (HES) remain at an earlier stage of development. HES refer to
the benefits to people produced by the effects of terrestrial ecosystems on freshwater resources
[18]. For example, one important HES for sustainable development is the provisioning of an
adequate supply of clean water, both for the role of clean water related to human health and
for the many uses of water such as agriculture and hydropower generation. Suitable HES
methods for large geographies are lacking, particularly in data-limited contexts, where using
sophisticated hydrologic models is constrained due to factors such as: insufficient data inputs,
limited ability to validate model outputs, lack of explicit connections of hydrologic processes
to ecosystem services and benefits to people, and difficulty with iterative modeling to identify
optimal priority areas. As such, simpler models that incorporate key features of an ecosystem
services analysis can be well suited to inform policy decisions related to coarse-scale spatial
planning in data-limited contexts [19,20].
Countries committed to sustainable development goals represent an ideal context for
advancing and applying these national-scale prioritization methods. The Gabonese Republic
(henceforth, Gabon) located in equatorial central Africa is exploring such planning efforts
now, motivated by high-level government commitments to sustainable development through
an “Emerging Gabon” strategy initiated by the president in 2010. This strategy includes a com-
mitment to protect and sustainably use the country’s natural resources for environmental pro-
tection, economic development, and human well-being [21,22]. In 2002, Gabon took steps to
protect its biodiversity resources through the establishment of a system of national parks cov-
ering ~10% of the country’s land base, setting a striking precedent. However, much more com-
prehensive planning is needed to enable the multi-faceted national commitment to a
sustainable natural resource future.
Hydrologic services priority areas in Gabon
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Abbreviations: HES, hydrologic ecosystem
services.
Here, we make a key advance towards these goals by creating and applying a simple, trans-
ferrable methodology for identifying HES priority areas, and evaluating their tradeoffs and
synergies with other environmental and development elements. We have generated the first
national-scale maps of HES priority areas across Gabon, providing decision-makers with pol-
icy-relevant, coarse-scale information about where ecosystems are currently providing critical
HES benefits to people that could be lost through unsustainable development activities.
The analysis addressed four questions: (1) At a national scale, where are the most important
regions to protect HES and to what extent and where do multiple HES overlap? (2) Are HES
priority areas the same to meet the needs of urban and rural communities? (3) To what extent
do HES priority areas overlap with other conservation priorities, particularly conservation val-
ues contained in the country’s terrestrial national parks and areas of high forest carbon stocks?
(4) To what extent are there potential conflicts between HES priority areas and current or pro-
posed development activities?
Methods
Gabon—Country overview and policy context
The country of Gabon is located in equatorial Central Africa and covers a land surface of
267,667 km
2
, which is approximately the size of the United Kingdom or the state of Colorado,
USA. The country is 85% forested and 87% of the total population of 1.63 million people live
in urban areas [23]. For decades, Gabon’s economy has been driven by oil exports, yet revenue
from this primary source is declining [21]. Manganese and timber are the other major exports
in this natural resource-rich country. Owing to its relatively low population yet economically
valuable natural resource exports, the country has a relatively high gross domestic product per
capita at US$ 14,747 (compared to, for example, US$ 3,404 in the neighboring country of
Congo) [23]. This wealth, however, is not evenly distributed as an estimated one-third of the
population is affected by poverty [21].
In 2010, President Ali Bongo Ondimba announced a plan called “Emerging Gabon” to
embark on a major transition to grow and diversify the economy away from its decades-long
dependence on oil exports. The plan aims to incorporate multiple industries, particularly
energy (i.e., expanding hydropower alongside continued oil extraction), mining, forestry, tour-
ism and agro-industrial operations [21]. Advancing these activities and building the transpor-
tation infrastructure to bring goods to market will have direct and indirect impacts on
ecosystems and their associated benefits to people. This situation highlights the challenging
reality of sustainable development that many rapidly developing nations, like Gabon, face:
how to develop natural capital without undermining biodiversity and ecosystem services.
Gabon is advancing its efforts for sustainable development through a national land-use
planning process and establishing new regulations and standards, among other policy efforts.
Our national-scale analysis of HES aimed to support these time-sensitive efforts by filling gaps
in existing information about where effective stewardship of Gabon’s ecosystems is most criti-
cal to ensure continued delivery of HES benefits for urban and rural populations and to avoid
unintended impacts from planned development activities.
Identifying priority areas for hydrologic ecosystem services
Conceptually, we defined HES priority areas as sub-regions of the country that provide the
highest levels of water quantity and quality benefits to people in both urban and rural commu-
nities. If ecosystems in these priority areas were heavily degraded through unsustainable land
use practices, we would expect there to be severe losses in the provision of HES and subsequent
Hydrologic services priority areas in Gabon
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impacts to people. We translated this working definition into a spatial methodology as
described below in the Hydrologic ecosystem services modeling section.
Our analysis focused on three HES: erosion control, nutrient retention, and groundwater
recharge. This selection was based on their importance in providing a clean supply of water to
people in Gabon; the potential for development activities to degrade that water supply (e.g.,
timber extraction, agricultural intensification, mining); and the availability of sufficient data
inputs for analysis. Taken together, the three HES provide an informative, though not exhaus-
tive, subset of services relevant to current and emerging policy decisions.
The erosion control analysis evaluated the contribution of functioning forests, wetlands, and
other ecosystems to retaining soil, and thereby reducing erosion and sediment runoff into
streams and rivers. The ecosystem service of erosion control can help prevent unintended
impacts from development activities to drinking water supply, fish habitat, and hydropower
reservoir longevity, amongst other erosion-related concerns. The analysis focused specifically
on sheetwash, rill, and gully and bank erosion, given our focus on HES that relate the effects of
terrestrial ecosystems on freshwater resources.
The groundwater recharge analysis evaluated the role of surface vegetation and soils in cap-
turing water and facilitating its movement into unconfined aquifers in places where the geo-
logic deposits are able to store and release water. Groundwater recharge to unconfined
aquifers is essential for replenishing the water supply that is tapped by small community wells
as well as larger commercial operations such as water bottling plants. This HES can help
increase the security of water supplies in communities serviced by wells, and potentially lower
extraction costs by minimizing the depth to the water table.
The nutrient retention analysis evaluated the role of functioning ecosystems in removing a
portion of the nitrogen and phosphorus contributed by non-point sources. This HES can pre-
vent surface water contamination associated with agricultural production and human and ani-
mal waste, and in doing so, potentially decrease water treatment costs and reduce nutrient-
related health risks. While nutrient loading into freshwater ecosystems from human land use
activities is not currently known to be a major threat in most of Gabon, expected agricultural
expansion and the growth of cities and villages will increase the importance of nutrient reten-
tion provided by ecosystems.
Hydrologic ecosystem services modeling
We modeled HES using the Resource Investment Optimization System (RIOS) v1.0.0b10 [24].
RIOS is a free and open-source software tool that prioritizes where and which types of
improved watershed stewardship activities will be most effective at achieving stakeholders’
conservation goals across multiple benefits [25]. We used RIOS to identify locations in Gabon
where activities that protect or maintain existing ecosystem functions are most beneficial to
the continued provision of the focal HES benefits. This represents a scientifically-grounded
but relatively simple modeling approach that could be deployed in other rapidly developing
countries which, like Gabon, are pursuing time-sensitive policy efforts for sustainable develop-
ment yet have relatively limited technical capacity and limited or coarse data necessitating a
simpler modeling framework to inform policy decisions. Below, we provide an overview of the
RIOS modeling framework with more details on the model structure and assumptions in S1
Appendix.
RIOS produces scores representing the likely effectiveness of activities across each user-
defined spatial unit in the planning region, which we defined as a 90-m pixel. Key inputs
include spatial data layers for biophysical factors, such as climate, soils, topography, land use /
land cover, and coefficients defining sediment, nitrogen, or phosphorus export and retention
Hydrologic services priority areas in Gabon
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values linked to land use / land cover categories (Figs 1and 2,Table 1). RIOS uses this infor-
mation to identify where conditions are predicted to be most favorable for protecting or
enhancing ecosystem services supply to people, based upon a systematic spatial analysis that
considers conditions on an individual pixel as well as the landscape context defined by the
hydrologic flow path. Specifically, for each pixel, the model evaluates net inputs from upslope
areas and net retention in downslope areas.
The RIOS modeling analysis used the following biophysical spatial data layers, which are
listed below with their data sources and in the same order as in Fig 1. More information is also
provided in S1 Appendix on how each data layer factors into the calculations for each HES:
1. Mean annual precipitation obtained from [26];
2. Rainfall erosivity obtained from [27]. Original cell values at 0.25˚ ×0.25˚ spatial resolution
were interpolated to a 90-m pixel size using a nearest neighbor resample to increase resolu-
tion at the country-scale relative to this continental dataset;
3. Mean annual evapotranspiration, which was obtained from the MOD16 Global Terrestrial
Evapotranspiration Data Set [28];
4. Potential groundwater recharge areas were identified based upon interpretation of the
national geology map [29], stream gage data, topography, land cover, and a nation-wide
water resources assessment.
5. Soil erodibility, for which values were defined based upon texture information from [30]
and additional guidance from the sediment retention model from [31];
6. Maximum soil depth, for which values were assigned based upon information from [30] to
approximate the soil depth to a restrictive layer;
7. Soil texture rank, for which values were assigned based upon texture information from [30]
to represent relative categories from coarse-grained to fine-grained;
8. Sub-watersheds, which we developed for our analysis to create hydrologically consistent poly-
gons sized 101–1,000 km
2
to summarize the RIOS model results to identify priority areas;
9. Land use / land cover, which was based upon information from [32]. To capture additional
features not represented and also changes that occurred since this base layer was published,
supplemental urban, industrial, agricultural, road, and wetland features were incorporated
from additional data sources and digitized using Google Earth and Microsoft Bing imagery
base maps. Areas of forest loss were obtained from [33].
Because ecosystem services describe the benefits from nature to people, it is important to
complement the biophysical inputs with information that accounts for where people live
across the country and from where on the landscape they receive benefits from ecosystems.
This concept is referred to as a “serviceshed” [34,35]. RIOS incorporates servicesheds and ben-
eficiary information in its prioritization calculations; more details on how these inputs were
generated are provided below in the Delineating HES servicesheds section.
All of these model components were used to generate normalized relative ranking scores
for each pixel in the landscape. To provide an illustrative example in the context of erosion
control, RIOS generates a high priority score for the protection of a forested pixel that is in a
location with (i) a high modeled upslope source of soil erosion entering the pixel, (ii) a low
modeled potential for downslope retention of eroded soil, and (iii) where the location of the
forested pixel will help to prevent erosion that would otherwise negatively impact important
areas for people living downstream (e.g., via a municipal water intake).
Hydrologic services priority areas in Gabon
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Fig 1. Spatial biophysical inputs for hydrologic ecosystem services modeling. Data sources are described in the main text.
https://doi.org/10.1371/journal.pone.0179008.g001
Hydrologic services priority areas in Gabon
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Delineating HES servicesheds. Gabon’s development strategy seeks to support urban
populations as they grow while also supporting and stabilizing rural populations. To reflect
these dual goals, we created two sets of servicesheds (Fig 3), allowing distinct analyses of HES
provision to the entire national population versus focusing on rural populations, given the lat-
ter’s more direct exposure to changes in the condition of ecosystem services. Furthermore,
lower population densities in rural areas dampen the importance of services provided to them
in a full national analysis (though a different approach was taken for groundwater recharge, as
described below). As such, this justifies the value of an assessment prioritizing rural popula-
tions, so their HES needs are not lost in the national-scale analysis that is more heavily
weighted towards Gabon’s urban populations.
One set of servicesheds, titled “all population”, was constructed to reflect the entire spatial
distribution of people across the country (Fig 3A). Because ~87% of Gabon’s population is
urbanized, this scenario heavily weights HES priority areas towards locations that benefit large
cities. To clarify and emphasize benefits or impacts to the smaller and more spatially distrib-
uted rural populations, we created another set of servicesheds titled “rural-weighted” (Fig 3B).
The rural-weighted servicesheds were created by excluding population data for Gabon’s three
largest cities (Libreville, Port Gentil, Franceville), which account for ~54% of the total
population.
For both sets, servicesheds for erosion control and nutrient retention were generally
defined as upstream source watersheds, because these services are important determinants of
the quality of drinking water supplies. To define these areas, we delineated sub-basins ranging
from 1,001 to 10,000 km
2
, derived from HydroSHEDs flow direction raster data at 3 arc-sec-
ond (90-m) resolution [36] using the flow accumulation and watershed commands in a GIS
[37]. This size range is approximately equivalent to 8-digit hydrologic unit code boundaries
(1,813 km
2
average size) in the US National Watershed Boundary Dataset [38]. We chose to
use sub-basins as the units for servicesheds, because hydrologic units are most appropriate for
Fig 2. Land use/land cover map for Gabon used in the analysis.
https://doi.org/10.1371/journal.pone.0179008.g002
Hydrologic services priority areas in Gabon
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evaluating HES, and they can be delineated upstream of points of human use or other impor-
tance (e.g., municipal water intakes).
Within each sub-basin, we estimated for each pixel the number of people downstream that
would benefit from a conservation activity on that pixel. To do this, we used: (i) the digital ele-
vation model from [36], which was used to produce hydrologic flow direction and accumula-
tion grids using the ArcGIS Spatial Analyst project raster, fill, flow direction, and flow
accumulation tools [37]; and (ii) the LandScan 2012High Resolution Global Population Data
Set, which provided the spatial distribution of ambient population (average over 24 hours)
[39]. To do this, LandScan spatially allocates census information using a dasymetric model.
The output of this process provided the weight for each pixel within each sub-basin in terms of
importance to beneficiaries for each serviceshed map.
Table 1. Normalized land use / land cover coefficients for the RIOS modeling. Based upon coefficients determined from literature review from [24,25].
More land use / land cover categories are listed here than in Fig 2, which groups multiple similar categories for display purposes (e.g., Agriculture). Higher val-
ues represent a greater level of impact for that factor (e.g., the highest sediment export value corresponds to the highest relative level of export acrossall land
use / land cover categories).
Land Use / Land Cover
General Category
Sediment
Export
Sediment
Retention
Nitrogen
Export
Nitrogen
Retention
Phosphorus
Export
Phosphorus
Retention
Vegetation
Rough Rank
Vegetation
Cover Rank
Dense moist forest 0.003 0.75 0.054 0.924 0.152 1 0.75 0.714
Mountain forest 0.003 0.75 0.074 0.924 0.041 1 0.75 0.714
Edaphic forest 0.003 0.94 0.662 0.498 0.195 0.626 0.75 1
Mangrove 0.003 0.87 0.106 1 0.029 0.626 0.75 1
Forest-savanna mosaic 0.003 0.83 0.054 0.588 0.008 0.653 0.163 0.357
Closed to open
deciduous woodland
0.003 0.75 0.054 0.924 0.01 1 0.5 0.714
Savanna woodland-Tree
savanna
0.003 0.83 0.054 0.588 0.008 0.653 0.163 0.357
Shrubland 0.5 0.505 0.006 0.515 0.011 0.367 0.069 0.357
Grassland 0.003 0.83 0.054 0.588 0.008 0.653 0.163 0.357
Aquatic grassland 0.003 0.94 0.022 0.498 0.007 0.626 0.75 1
Wetland 0.003 0.94 0.022 0.498 0.007 0.626 0.75 1
Water bodies 0.04 0.2 0 0.07 0 0.83 0.0001 0
Rural complex and young
secondary forest
0.111 0.81 0.057 0.73 0.065 0.816 0.471 0.843
Mosaic cultivated areas /
vegetation (herbaceous
or shrub)
0.111 0.81 0.057 0.73 0.065 0.816 0.471 0.843
Artificial surfaces and
associated areas (e.g.,
urban)
0.1 0.2 0.222 0.494 0.277 0.272 0.014 0.029
Village (population
2003 >10,000)
0.1 0.2 0.222 0.494 0.277 0.272 0.014 0.029
Village (population 2003
<= 10,000)
0.111 0.81 0.057 0.73 0.065 0.816 0.471 0.843
Road 0.5 0.13 0.127 0.116 0.38 0.136 0.001 0
Mine (active concession) 1 0.26 0.127 0.116 0.055 0.136 0.013 0.114
Forest loss (from Hansen
et al. 2013)
0.111 0.81 0.057 0.73 0.065 0.816 0.471 0.843
General Agriculture 0.19 0.84 0.138 0.802 0.142 0.796 0.163 0.814
Coffee 0.11 0.84 0.138 0.802 0.142 0.796 0.163 0.814
Sugarcane 0.24 0.84 0.105 0.802 0.074 0.796 0.163 0.814
https://doi.org/10.1371/journal.pone.0179008.t001
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We used this systematic approach to create servicesheds for rural communities and smaller
cities, since existing information on surface water supply boundaries was not available for the
entire country and these locations did not have infrastructure in place for trans-basin water
diversions. Rather, they largely draw surface water from their local surroundings. However,
for the “all population” scenario that included the largest cities of Libreville, Port Gentil, and
Franceville, we used information provided by the national electric and water utility (operated
by Socie
´te
´d’e
´nergie et d’eau du Gabon, SEEG) to identify intake points that did incorporate
trans-basin diversions. From these points, we delineated the source watershed areas that pro-
vide municipal water supply and then, as above, weighted each pixel by the effective down-
stream urban population.
For the ecosystem service of enhancing groundwater recharge, we took a different approach
to defining the serviceshed. Groundwater is both used by local communities and, in the case of
a large aquifer in the Bate
´ke
´plateau, exported as bottled water to locations across the country.
Because of this mix of local and exported uses, in the serviceshed input we placed an equal
weighting of importance for all of the potential groundwater recharge areas across the country.
As a result, the relative ranking scores we generated for groundwater recharge were not
affected by the location or density of people across the landscape. Accordingly, only one servi-
ceshed was included rather than separate ones for “all population” and “rural-weighted”.
Summarizing model results to identify priority areas. For the national-scale analysis,
our goal was to identify which sub-watersheds were more versus less important for protecting
HES. As such, we summarized the RIOS pixel ranking scores by calculating mean values
within sub-watersheds ranging from 101 to 1,000 km
2
(Fig 1H). This size range is approxi-
mately equivalent to 10-digit (588 km
2
average size) or 12-digit (104 km
2
average size) hydro-
logic unit code boundaries in the US National Watershed Boundary Dataset [38].
Fig 3. Servicesheds for erosion control, nitrogen retention, and phosphorus retention weighted by
downstream beneficiary population size. (A) “All population” serviceshed. (B) “Rural-weighted”
serviceshed. Pixel values represent the number of downstream people within each serviceshed that would
benefit from a watershed conservation activity on that pixel. Therefore, pixels with the highest values are
those with the largest downstream population.
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Hydrologic services priority areas in Gabon
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Furthermore, this size enabled division of priority areas within the larger servicesheds
described above (approximately 8 digit hydrologic unit code boundaries). We excluded sub-
watersheds that extend outside of Gabon’s boundary if less than one-third of the area was
inside Gabon. This was a conservative approach but practically resulted in very few sub-water-
sheds being eliminated from the analysis.
We further binned the sub-watershed results into five categories ranging from highest to
lowest priority for protecting each of the HES across the country. Each category represents
approximately 20% of the total area of the country. We deemed this quintile approach to be
appropriate for the study context given feedback from Gabonese stakeholders who we engaged
during the analysis. We defined the priority areas for each HES as being the top 20% category,
which represents the upper quintile (see Fig 4 in Results). In addition, for the “all population”
and “rural-weighted” scenarios, we created composite HES priority area maps by overlaying
the individual maps for each HES and identifying if a sub-watershed was prioritized for one or
multiple HES (see Fig 5 in Results).
For our analysis, we used the best available data inputs, but the least certain input was the
soils data [30]. As described above, we used the soils data to extract information for individual
spatial data inputs on three soil properties: soil erodibility, maximum soil depth, and soil tex-
ture (Fig 1E–1G). To guard against potential bias, we conducted a sensitivity analysis in which
we reran the entire priority area analysis described above but removing one of the soil property
inputs each time from the analysis. We observed minimal changes to the resulting priority
areas in each case, which increased our confidence that the priority areas were not unduly
influenced by uncertainty in individual properties from the underlying soils data.
Overlap of HES priority areas with other conservation and development
attributes
We quantified the degree to which the identified HES priority areas had tradeoffs or syner-
gies with important areas for two other important conservation interests in Gabon: (1) the
existing system of terrestrial national parks for its biodiversity protection and broader con-
servation benefits. Park boundaries were identified from a GIS layer provided by the
National Parks Agency (Agence Nationale des Parcs Nationaux, ANPN). While important
biodiversity benefits are found outside of parks, we focused on parks because of the official
commitment Gabon has made to protect these areas and mitigate threats (e.g., illegal extrac-
tive activities), which can in turn provide insight about the degree to which effective parks
management can also help protect HES priority areas; and (2) protecting forests with high
carbon stocks for their global climate change mitigation benefit. For each pixel in our analy-
sis, the total biomass carbon stock of forests (above- and belowground) was quantified using
data for Gabon from [16].
We also evaluated the degree to which the identified HES priority areas intersected with
areas important for current or proposed development activities. Given available data, we
focused our analysis on: (i) the current network of paved primary roads and the major road
alignments that are projected to be paved in the future, based upon data obtained in March
2015 from the national agency for major infrastructure planning, Agence Nationale des
Grands Travaux, ANGT, (ii) the location of currently active mines, and (iii) the location of all
forestry concessions, the subset that have sustainable certification as of March 2015 [40], and
information on forest cover loss in concessions from 2000 to 2013 based upon information
summarized from the high-resolution maps of global forest cover change produced by [33].
Information on potential new mining concessions and new agricultural concessions (e.g.,
palm oil or rubber plantations) was unavailable to incorporate into this analysis.
Hydrologic services priority areas in Gabon
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Results
HES priority areas at the national scale
The priority areas for each HES (representing the top 20% by area of sub-watersheds) are
spread throughout the country, with partially different patterns across the services and for the
“all population” versus “rural-weighted” scenarios (Fig 4). For reporting of results, we focus on
these priority areas, while providing in S1 Fig all of the sub-watershed results divided into
quintiles of highest to lowest priority. As we did not have information on thresholds to deter-
mine what levels of provision across the focal HES are critical to the population, and therefore
what amount of land area needs to be maintained to meet this need, the 20% area portfolios
should not be interpreted as a minimum area to retain in good condition. Rather, it should be
taken as a first, coarse-scale indication of areas in which HES are most sensitive to
development.
The results show the greatest spatial overlap in priority areas for erosion control and nutri-
ent retention (nitrogen and phosphorus), with groundwater recharge having substantially less
overlap. The portfolio created by combining priority areas for all three HES covers approxi-
mately 44% (or ~116,000 km
2
) of the country’s area for the “all population” scenario and 43%
(or ~115,000 km
2
) for the “rural-weighted” scenario (Fig 5). Notably, priority areas important
for all HES objectives in the same sub-watersheds are found in only a small portion of the
entire country, specifically 3% for the “all population” scenario and 1% for the “rural-
weighted” scenario.
Comparing results for the “all population” and “rural-weighted” scenarios shows that there
is 53% overlap between the two scenarios (Fig 5). This overlap is mostly driven by groundwater
recharge priority areas (which are not different between the two scenarios) and some addi-
tional areas for erosion control and nutrient retention. However, both erosion control and
nutrient retention priority areas show notable shifts between scenarios, meaning that protect-
ing these values for rural populations will require specific policy attention (Figs 4and 5).
Overlap of HES priority areas with other conservation and development
attributes
We evaluated the overlap of HES priority areas with two other indicators of conservation value
important in Gabon: (1) terrestrial national parks and (2) forest carbon stocks. Across the
approximately 3 million km
2
of parks, 38% intersects with an HES priority area in the “all pop-
ulation” scenario compared to 25% for the “rural-weighted” scenario (Fig 6). The greatest
overlap is for groundwater recharge priority areas and also for servicesheds for erosion control
and nutrient retention that support larger cities.
For forest carbon stocks, the mean area-weighted total stock across all sub-watersheds was
154 MgC ha
-1
. Relative to this value, 66% of the priority areas for the “all population” scenario
and 69% of the priority areas for the “rural-weighted” scenario have above average area-
weighted total forest carbon stocks. Groundwater recharge priority areas tended to fall in areas
with a greater fraction of savanna or forest/savanna mosaic, and therefore had lower carbon
stocks than fully forested areas.
We also evaluated the overlap of HES priority areas with three indicators of current human
activities and proposed development projects that had available data: primary paved roads
(existing and proposed alignments), active mines, and forestry concessions (Fig 7). Gabon has
a total of 1,672 km of existing primary paved roads as of March 2015 and there are proposed
projects to nearly double that length by adding 1,495 km of new major paved road alignments.
For existing roads, 66% of the total length goes through an HES priority area for the “rural-
Hydrologic services priority areas in Gabon
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Fig 4. Priority areas of sub-watersheds (top 20% by area) for each hydrologic ecosystem service. (A-C) Erosion control, nitrogen retention, and
phosphorous retention for the “all population” scenario. (D-F) Erosion control, nitrogen retention, and phosphorous retention for the “rural-weighted”
scenario. (G) Groundwater recharge for the single scenario (i.e., not weighted by population distribution). Grey lines show the boundaryof all the sub-
watershed polygons.
https://doi.org/10.1371/journal.pone.0179008.g004
Hydrologic services priority areas in Gabon
PLOS ONE | https://doi.org/10.1371/journal.pone.0179008 June 8, 2017 12 / 21
weighted” scenario compared to 46% for the “all-population” scenario. For proposed roads,
54% of the total length goes through an HES priority area for the “rural-weighted” scenario
compared to 37% for the “all-population” scenario.
The direct spatial footprint of active mining concessions in Gabon covers an estimated area
of 595 km
2
. Of this total active mining concession area, 44% intersects with an HES priority
area for the “rural-weighted” scenario, whereas there is very limited intersection (0.4%) for the
“all population” scenario (Fig 7A and 7B).
Forestry concessions cover an estimated area of 142,146 km
2
(or 53% of the country’s total
land surface), though only a portion of these concessions is active with localized harvest under-
way. Of this total forestry concession area, 39% intersects with an HES priority area for the
“rural-weighted” scenario compared to 35% for the “all population” scenario (Fig 7C and 7D).
In areas where harvesting activity is occurring, there is relatively greater potential for nega-
tive impacts on HES. Using data from [33], we calculated 997 km
2
of forest loss across all for-
estry concessions from 2000–2013 (which is 33% of the 3,058 km
2
of forest loss across the
entire country). Of this total, 47% occurs in areas of forestry concessions that intersect with
“rural-weighted” portfolio areas compared to 32% for the “rural-weighted” scenario. Over that
time period, this result indicates that there has been relatively less harvesting activity occurring
Fig 5. The portfolio of combined hydrologic ecosystem services priority areas. (A) “All population” scenario. (B) “Rural-weighted” scenario. (C)
Overlap between these scenarios. For (A) and (B), percentage areas (of the total country area) are reported for each unique combination of the HES
objectives. For (C), the percentage area of overlap and separation is reported across the two scenarios.
https://doi.org/10.1371/journal.pone.0179008.g005
Hydrologic services priority areas in Gabon
PLOS ONE | https://doi.org/10.1371/journal.pone.0179008 June 8, 2017 13 / 21
in prioritized versus not prioritized areas, with the signal stronger for the “all population”
scenario.
Sustainably certified forestry concessions identified from [40] cover an estimated area of
20,622 km
2
(or 15% of the total forestry concession area), and best management practices can
help mitigate potential conflict between forestry operations and HES. Of the total area of certi-
fied concessions, 47% intersects with an HES priority area for the “rural-weighted” scenario
and 42% for the “all population” scenario (Fig 7).
Fig 6. Overlap of hydrologic ecosystem services priority areas with other indicators of conservation value.
Overlap with national parks (shown in black outline) for (A) “all population” and (B) “rural-weighted” scenarios. All
other colors represent portfolio sub-watersheds as described in Fig 5. Overlap with forest carbon stocks below or
equal to (orange color) or above (purple color) the average sub-watershed total carbon stock across the country (154
MgC ha
-1
) for (C) “all population” and (D) “rural-weighted” scenarios.
https://doi.org/10.1371/journal.pone.0179008.g006
Hydrologic services priority areas in Gabon
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Discussion
We developed a novel analysis to identify national-scale HES priority areas to inform planning
for sustainable development. Our results provide the first such prioritization for HES across
Gabon, while providing a replicable methodology transferable to new geographies and policy
contexts. In doing so, we contribute to the advancement of science that can inform sustainable
Fig 7. Overlap of hydrologic ecosystem services priority areas with indicators of economic development activities. (A) “All
population” scenario with active mining concessions and roads. (B) “Rural-weighted” scenario with active mining concessions and roads. (C)
“All population” scenario with forestry concessions. (D) “Rural-weighted” scenario with forestry concessions.
https://doi.org/10.1371/journal.pone.0179008.g007
Hydrologic services priority areas in Gabon
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development decisions to ensure that the benefits people get from nature are quantified and
known to decision-makers (e.g., [41,42]).
Our results provide four overarching insights that could assist Gabonese decision-makers
in constructing a refined HES portfolio strategy from the matrix of information we provide in
this paper. First, there are important differences in the location of priority areas for different
HES, so creating a comprehensive portfolio that protects water supply and quality for urban
and rural communities will require careful selection of the most appropriate locations for each
HES. Areas that provide all HES examined in our analysis and thus protect multiple benefits
simultaneously covered only 1 to 3% of the country for the two scenarios (Figs 4and 5). While
these are efficient places to focus attention first, they are not sufficient. We also found limited
overlap in priority areas for groundwater recharge relative to erosion control and nutrient
retention, which was driven by the fact that areas identified as being suitable for groundwater
recharge are located in largely separate parts of the country from those places with the most
erodible soils, highest and most intense rainfall, and the most important servicesheds for ero-
sion control and nutrient retention (Figs 1and 3).
Second, additional efficient gains will be made for both urban and rural residents in the
~53% of sub-watersheds that were prioritized in both the “all population” and “rural-
weighted” scenarios (Fig 5). That said, selecting priority areas beyond where there is overlap
will be needed to reach the largest cities and the more spatially expansive rural populations.
The maps provided here can help policymakers identify where to best meet the needs of these
specific parts of the national population to advance Gabon’s goal to support and stabilize rural
communities while also securing services to growing urban areas.
Third, HES priority areas have some, but limited, potential to capture co-benefits for pro-
tecting high forest carbon stocks and biodiversity found in national parks (Fig 6). Synergies
were not substantial enough for carbon or parks to suggest that investments in any of these
individual benefits could serve as a comprehensive nationwide “umbrella” strategy for the oth-
ers. With respect to forest carbon, however, Gabon has high values from a global perspective
[16]. Therefore, our analysis should be interpreted with the perspective that protecting forests
in Gabon is broadly valuable for global climate change mitigation. With this recognition, HES
priority areas that overlap even average carbon stock areas could be considered as having sub-
stantial carbon co-benefits. In addition, further analysis is needed to better understand the
degree to which HES priority areas could support important elements of biodiversity in Gabon
that are not already covered by the existing system of terrestrial national parks, which we
focused on in our analysis.
Fourth, potential conflicts exist between development activities and HES priority areas, par-
ticularly for the “rural-weighted” scenario (Fig 7). This is not surprising because mining and
forestry activities are mostly located and planned in rural parts of the country, and also because
primary roads have long stretches through rural areas. Furthermore, while our overlap analysis
focused on the direct footprint of development activities, there are often much larger spillover
impacts such as roads facilitating indirect land use change [4] and mining requiring energy
and other resources from the surrounding landscape [43]. For all these reasons (and also
because spatial data sets were not available on all future development activities), our analyses
of potential conflicts provide components of a first screening at a national scale that can guide
where developing more detailed site-specific analyses is most needed.
In this context, effective policy frameworks and planning processes will be key to proac-
tively protect HES, reduce actual conflicts with development, and mitigate impacts that do
occur. The mitigation hierarchy—focused on avoiding, mitigating, and offsetting or compen-
sating for impacts—provides a policy framework to connect information on HES priority
areas to economic development decisions, since at least 56 countries have existing or are
Hydrologic services priority areas in Gabon
PLOS ONE | https://doi.org/10.1371/journal.pone.0179008 June 8, 2017 16 / 21
developing (as in the case of Gabon) national mitigation policies [44]. HES priority areas can
add to an understanding of where development should be avoided to minimize impacts, and
where mitigation offsets can be directed to maximize benefits and reduce offset costs. Further-
more, major financial institutions increasingly require adherence to the mitigation hierarchy
for projects they finance. Notably, the International Finance Corporation’s Performance Stan-
dard Number 6 now includes specific language on managing and mitigating impacts to ecosys-
tem services, in addition to biodiversity [45]. HES priority area information can be used to
come into compliance with this or similar ecosystem-service standards [46].
Our approach provides a means to blend systematic conservation planning for HES with
the mitigation hierarchy that can support sustainable development [9,47]. The HES priority
areas that we identified for Gabon are at a spatial resolution that should be interpreted as a
general indication of areas of importance, and could be used to inform broad-scale national
development plans. They should not, however, be considered as strict avoidance areas for spe-
cific development projects. Within the priority areas we identified, finer-scale analysis is neces-
sary to identify site-specific avoidance areas that have the most critical watershed features
warranting strict protection, as well as where development activities are most compatible.
Moving to offsets of residual impacts that occur from development activities, the delineation
of servicesheds provides a means to account for which populations will be harmed and which
could benefit from planned mitigation. From an equity perspective, the best option is to site
offsets that restore HES to the same affected populations rather than having offset activities
occur in other servicesheds resulting in a spatial transfer of benefits [35]. Residual impacts in
priority areas could also warrant higher offset ratios given their importance in protecting HES
for the country [20].
Future research could build upon our work in at least four ways:
1. For national governments to identify true priority areas and be assured that levels and loca-
tions of development are sustainable, they need to better understand the critical or thresh-
old levels of service provision needed. This would be equivalent to replacing our context-
relevant but arbitrary 20% area threshold for priority area identification with service provi-
sion thresholds that reflect future needs, preferences for, and alternatives for these services.
Such estimates need to be made while considering HES supply relative to demand and
incorporating the role of built infrastructure (e.g., water treatment plants) in providing
health, sanitation, and other services to people.
2. Analyses should move from evaluating priority areas based upon relative ranking scores to
absolute values (e.g., tons of avoided soil loss which reduces sedimentation and associated
costs to hydropower reservoirs and drinking water treatment plants). A modeling challenge
in data-limited geographies will be to acquire sufficient data to reflect key processes and to
validate more sophisticated model applications.
3. Conduct finer-scale analysis as described above to inform site-level decisions in priority
areas to allow consideration of HES for specific development projects.
4. Incorporate more ecosystem services (e.g., wild food harvest, flood mitigation, coastal and
marine services) and additional representations of important biodiversity areas (such as a
freshwater conservation portfolio or important but not legally protected terrestrial areas)
would give a more comprehensive view of conservation and human well-being outcomes
and impacts.
Our approach provides countries with a pathway for planning and policy efforts to consider
protection of HES as a core part of green economy and sustainable development strategies
Hydrologic services priority areas in Gabon
PLOS ONE | https://doi.org/10.1371/journal.pone.0179008 June 8, 2017 17 / 21
rather than these services being unintentionally harmed as a result of lack of information. Gen-
erating this information in a robust and decision-oriented way is a first step for bringing sci-
ence to decision-making. The ultimate measure of impact is demonstrating that this
information can inform smarter decisions about the role of ecosystem services, alongside bio-
diversity, in sustainable development trajectories.
Supporting information
S1 Appendix. Technical overview of the Resource Investment Optimization System
(RIOS).
(DOCX)
S1 Fig. Quintile scores for all sub-watershed polygons dividing the country into highest
(dark red) to lowest (dark blue) priority areas for each hydrologic ecosystem service. (A-C)
Erosion control, nitrogen retention, and phosphorous retention for the “all population” sce-
nario. (D-F) Erosion control, nitrogen retention, and phosphorous retention for the “rural-
weighted” scenario. (G) Groundwater recharge for the single scenario (i.e., not weighted by
population distribution). Grey lines show the boundary of all the sub-watershed polygons.
Each quintile represents approximately 20% of the total country area.
(TIF)
Acknowledgments
We thank Joe Fargione, Bronson Griscom, Justine Hausheer, Jonathan Higgins, Peter Kareiva,
Erik Lowe, Matt Miller, Paulo Petry, Adrian Vogl, and Stacie Wolny for constructive manu-
script suggestions and/or assistance with analyses throughout the process of this project. We
are also very grateful to professional staff and managers at the Gabonese National Parks
Agency (Agence Nationale des Parcs Nationaux, ANPN), at the National Research Center
(Centre National de la Recherche Scientifique et Technologique/Institut de Recherche Agro-
nomique et Forestière, CENAREST/IRAF), and the Ministry of Water and Forests (Ministère
des Eaux et Forets, MINEF), for their support and engagement in the development of the
Freshwater Atlas for Gabon, for which the analysis presented in this paper originated.
Author Contributions
Conceptualization: JHG HT AC SS EM MH MP AA CA BN.
Data curation: JHG HT AC SS EM MH AA BN.
Formal analysis: JHG HT AC SS EM MH AA BN.
Funding acquisition: HT MP CA.
Investigation: JHG AC SS EM MH AA.
Methodology: JHG HT AC SS EM MH AA BN.
Project administration: HT MP BN.
Resources: JHG AC SS EM MH AA.
Software: AC SS EM MH BN.
Supervision: HT MP.
Visualization: JHG AC SS EM BN.
Hydrologic services priority areas in Gabon
PLOS ONE | https://doi.org/10.1371/journal.pone.0179008 June 8, 2017 18 / 21
Writing – original draft: JHG HT AC SS EM MH MP AA CA BN.
Writing – review & editing: JHG.
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... The coast of Gabon contains Africa's third largest freshwater delta, and possibly one of the most intact across the continent if not globally . Wetlands of the Ogoou e delta, known as the Bas Ogoou e, and coastal habitats to the north and south are a complex mosaic of freshwater, estuarine and dryland habitats that provide a wealth of important ecosystem services for people and nature (Goldstein et al. 2017). They filter water and remove sediments and toxins that may arise from upstream urban areas and agricultural, forestry and mining operations; and they absorb water during the rainy season and minimize downstream floods to communities living in the riparian or floodplain zones (Coughanowr 1998). ...
... The purpose of this project was to develop an accurate map of wetland habitats in the region in and around the Bas Ogoou e, Gabon. While wetland habitats across the country play important roles in provisioning of ecosystem services (Goldstein et al. 2017), they cover only 22% of the project area (or only 15% if open water is excluded), in comparison to nearly 75% cover in terra firme forests. However, the less common wetland habitat types likely have an effect on regional biodiversity and water quality and quantity that is disproportionate to their relatively small total area. ...
... However, the less common wetland habitat types likely have an effect on regional biodiversity and water quality and quantity that is disproportionate to their relatively small total area. This includes critical fish, bird, mammal and invertebrate habitat, including habitat for migratory species; flood mitigation, water purification and groundwater recharge and carbon storage (Goldstein et al. 2017). For example wetland mosaics such as the Emergent Wetland type generally leads to high richness of wetland species because the diversity of habitats can support different species and different life stages of individual species over a relatively small area. ...
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Abstract Wetlands of coastal Gabon provide many ecosystems services including flood protection, water purification and wildlife habitat. Effective sustainable management of this coastal zone is hindered by a lack of accurate wetland maps. Here we describe a novel method used to map the wetland ecosystems of nearly 100 000 km2 of wetland and upland habitat mosaic in the delta of the Ogooué River using an object‐based classification of optical and radar satellite imagery based on training data collected from unmanned aerial vehicle and a post‐classification accuracy assessment using helicopter‐based video. We identified 15 land cover classes, of which nine were wetland. A stratified random sample accuracy assessment of the final classification yielded an overall accuracy of 0.80. Despite the important role that wetland habitats play for wildlife and ecosystem functioning across the region, our results indicate these wetlands cover only 22% of the project area. As expected, most of the wetland habitats are found close to major water bodies, including the Ogooué River, estuaries near the cities of Libreville and Port Gentil and coastal lagoons to the south of these cities. When considering the six Wetlands of International Importance designated under the Ramsar Convention within the project area, only 33% of mapped wetlands fall within the Ramsar site boundaries and only 10% of mapped wetlands fall within protected areas. Furthermore, within the Ramsar sites, only 31% of the land cover was classified as wetland. In order to better manage these wetland resources, more effective Ramsar boundaries would include the extensive wetland habitats found along the coast from Port Gentil south to Loango National Park. These data are now available for managers to improve wetland management within designated Ramsar sites and improving protection designations for vulnerable habitats, for example by protecting wetland connectivity and other ecosystem processes.
... Hydrological ecosystem services (HESs) are important to ecological management and protection within watersheds [1,2] and not only provide key natural resources to human society but also sustain freshwater ecosystem structure and ecological processes [2,3]. HESs include the provisioning of water in sufficient quality and quantity for agricultural, industrial, and residential uses and habitat provisioning for aquatic biota. ...
... Hydrological ecosystem services (HESs) are important to ecological management and protection within watersheds [1,2] and not only provide key natural resources to human society but also sustain freshwater ecosystem structure and ecological processes [2,3]. HESs include the provisioning of water in sufficient quality and quantity for agricultural, industrial, and residential uses and habitat provisioning for aquatic biota. ...
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Hydrological ecosystem services (HESs) such as water purification and water supply are important for providing other ecosystem services such as drinking water, recreation, and human health. Land use change caused by urbanization is a direct driver affecting the provision of HESs. The quantification and integration of HES into watershed management and urban planning have become increasingly important. In this study, we highlighted an integration of the InVEST and CLUE-S models to simulate and predict future changes of HES in a rapidly urbanizing lake basin, namely the Nansihu Lake basin of China. The spatiotemporal patterns of HESs including water yield, water purification, and sediment export in the past five decades (from 1980 to 2015) have been revealed through our integrated modeling approach. Furthermore, urbanization and land use change scenarios till 2030 were developed using land use, topography, climate, and soil data. It is found that due to the rapid expansion of urban land, water yield, total nitrogen (TN), and total phosphorus (TP) export has increased by 5.5%, 7.38%, and 7.02%, respectively, while the sediment export has decreased by 4%. As a result, the risks of flooding and water quality degradation increased. Under a hybrid ecological and farmland redline policy (EFRP) scenario, the HESs have all been significantly improved compared to the level in 2015. This research can help to predict the future changes in HESs for land use management and ecological and environmental protection in the Nansihu Lake basin.
... Traditionally, sophisticated hydrological models have been used to demonstrate how the execution of particular management activities can improve the delivery of hydrological ecosystem services (HES) across large geographic scales (Goldstein et al., 2017;Luke and Hack 2018). However, these approaches are constrained by factors such as; application effort, limited data availability for model implementation or validation and their inability to identify priority areas within a catchment for investment in EI (Goldstein et al., 2017). ...
... Traditionally, sophisticated hydrological models have been used to demonstrate how the execution of particular management activities can improve the delivery of hydrological ecosystem services (HES) across large geographic scales (Goldstein et al., 2017;Luke and Hack 2018). However, these approaches are constrained by factors such as; application effort, limited data availability for model implementation or validation and their inability to identify priority areas within a catchment for investment in EI (Goldstein et al., 2017). ...
... Traditionally, sophisticated hydrological models have been used to demonstrate how the execution of particular management activities can improve the delivery of hydrological ecosystem services (HES) across large geographic scales (Goldstein et al., 2017;Luke and Hack 2018). However, these approaches are constrained by factors such as; application effort, limited data availability for model implementation or validation and their inability to identify priority areas within a catchment for investment in EI (Goldstein et al., 2017). ...
... Traditionally, sophisticated hydrological models have been used to demonstrate how the execution of particular management activities can improve the delivery of hydrological ecosystem services (HES) across large geographic scales (Goldstein et al., 2017;Luke and Hack 2018). However, these approaches are constrained by factors such as; application effort, limited data availability for model implementation or validation and their inability to identify priority areas within a catchment for investment in EI (Goldstein et al., 2017). ...
... Here, we describe the process that followed, beginning with consistent delineation of the riparian zone with a spatial model, followed by review and validation by the local RBA and AETD, and finally approval and legislated protection by aimag khural (provincial parliament). The spatial model was developed as part of a framework for mapping and classifying riverine wetlands called Active River Area developed by Smith et al. [37] and widely applied for conservation planning in North America [38][39][40][41][42], Asia [43], Africa [44], and Australia [45]. ...
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Mongolia has globally significant biodiversity and pastoral traditions, and scarce water resources on which wildlife and people depend. Rapid growth of the mining sector is a threat to water resources and specifically river riparian zones. Mongolia has passed progressive laws for water and habitat conservation, including establishment of Integrated Water Resource Management (IWRM) and river basin governance organizations, and laws protecting the river riparian zone, but implementation is hindered by limited technical capacity and data-scarcity, specifically because consistent, accurate maps of the riparian zone did not exist. To address the gap, WWF-Mongolia and partners developed a national delineation of riparian areas based on a spatial model, then validated this with local River Basin Authorities and provincial governments to designate legal protection zones. As a result, 8.2 million hectares of water protection zones including riparian areas have been legally protected from mining and industrial development in the globally significant landscapes and riverscapes of the Amur, Yenisey, and Ob Rivers headwaters, the Altai Sayan ecoregion, and the Gobi-Steppe ecosystem. These findings demonstrate a pathway for implementing broad-scale, durable legal protection of riverine wetlands through a data-driven, participatory process.
... To be effective, conservation efforts should consider distributions of habitats, threats, and impacts at a regional-or landscape-level across biogeographic regions (Groves, 2003;Groves et al., 2002). A conservation portfolio of priority sites, the product of conservation planning, contains a set of areas selected to represent the full distribution and diversity of native species and ecosystems (e.g., Cameron, Cohen, & Morrison, 2012;Goldstein et al., 2017). ...
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Growing resource demands are driving rapid development to new frontiers in developing countries with important biological diversity. The mitigation hierarchy is a critical tool to manage the impacts of development projects on biodiversity, embedded into numerous government, lender, and corporate policies. However, implementation faces obstacles, in particular deciding when impacts should be avoided. Offset design, the last step, faces difficult questions about location of offsets relative to impacts and how to address uncertainty and conflicts with future development. Planning for conservation and development are typically separate processes, and environmental impact assessments are typically conducted on a project‐by‐project basis that does not consider the landscape context and cumulative impacts of multiple projects. Here we present a mitigation framework for Mongolia with an example from the Mongolian Gobi Desert, a landscape with globally significant biodiversity facing rapid development. This landscape‐level planning approach has been replicated across Mongolia to produce a national level mitigation framework to guide both the government policy commitment to protect 30% of all natural lands and application of the mitigation hierarchy. This has led to protection of 177,000 km2 in new national and local protected areas, and development of an offset design mechanism based on the conservation plans.
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