InVEST: Integrated Valuation of Ecosystem Services and Tradeoffs

Download InVEST Tier 1 Tools Version 1.003 beta (includes User's Guide)

Download InVEST Tier 1 Tools Version 1.003 beta User's Guide

Government officials, conservation professionals, farmers, and other land owners make decisions about how to use their land all the time. Yet, never before have any of these groups had a systematic way to demonstrate the future costs and benefits of their decisions for people and the environment. In its most ground-breaking effort, the Natural Capital Project aims to meet this challenge with InVEST, a new tool that can model and map the delivery, distribution, and economic value of life-support systems (ecosystem services), well into the future. The tool will help users visualize the impacts of potential decisions, identifying tradeoffs and compatibilities between environmental, economic, and social benefits.

How it Works

We begin by collecting as much information as possible about a given landscape. How much of the land is currently devoted to crops and/or forests? What percent is privately owned or managed? What are the zoning laws? The next step is to sit down with decision-makers and outline the scenarios that stem from different possible changes in land-use (development, restoration, or new government policies) and the desired outcomes (poverty alleviation, clean drinking water, and/or carbon sequestration).

Each scenario is then fed into InVEST’s unique modular structure: each module represents a different life-support system that can be evaluated independently or selected modules can be bundled together according to the specific scenarios and priorities in each place. InVEST can model and map the consequences of decisions on life-support systems in both economic and biophysical terms.

The impacts of each scenario on life-support systems are illustrated with easily interpreted maps, tradeoff curves, and balance sheets. These will be most relevant and useful if they are based on the specific opportunities and constraints identified by decision-makers and stakeholders which are unique to each community.

© Ottocarotto - February 2008 - View to the city of Tarma (Junín), Peru. Expansion of urban area shown. (http://commons.wikimedia.org/wiki/File:Tarmaperu1.JPG)

Our approach identifies where ecosystem service benefits originate and where they are consumed. It reveals how alternative choices about resource management will affect multiple aspects of the economy, human well-being and the environment. Our methodology can help answer these types of urgent questions:

© snakefisch - March 2005 - Hoover dam from plane (http://commons.wikimedia.org/wiki/File:Hoover_dam_from_air.jpg)

How will alternative patterns of urban growth impact the production of ecosystem services?

How does a proposed hydropower management plan affect hydropower production, biodiversity, water quality and recreation?

Where would reforestation achieve the greatest sustainable timber production and value for carbon sequestration and crop pollination?

Keeping it Simple: A multi-tiered approach

In addition to allowing users to decide which life-support systems to model and map, InVEST offers a multi-tiered approach so that users can choose the complexity of the outputs based on their specific needs and the quality and quantity of input data. Our models provide the flexibility to model and map life-support systems for a broad range of spatial resolutions. We have already demonstrated the ability of InVEST at scales ranging from the Willamette Valley in Oregon to global analysis.

Users choose the scale and model tiers based on their desired outputs, from relative scores for basic biophysical terms (Tier 1) to in-depth, high-resolution biophysical and economic terms (Tier 2 or Tier 3).

- Tier 1 is fundamentally simple, provides a relative sense of the level of services provided across the landscape and requires few input data.
- To calculate economic values, Tier 2 is required. Tier 2 provides a level of certainty needed to model economic terms realistically, but it needs more input data.
- Tier 3 is capable of including land cover and use dynamics, plant community succession, nutrient balances, and similar complex processes when the input data are available. Tier 3 usually includes existing models like the CENTURY model for carbon cycling or Ecosim for biodiversity modeling.

Flexible Outputs: Economic and biophysical terms

With InVEST, users can switch back and forth between economic and biophysical terms as they evaluate the costs and benefits of land-use or policy decisions. Water quality, for instance, can be readily understood by government regulators in biophysical terms, using Total Maximum Daily Loads (TMDLs) - established limits on contaminants or sediments used by U.S. government agencies. Alternatively, we can calculate the cost to the local community of water treatment in economic terms like dollars.

Technical Overview of the InVEST Toolbox

InVEST models run as script tools in the ArcGIS ArcToolBox environment. To run InVEST, you must have ArcGIS 9.2 (at least service pack 2.) ArcGIS 9.3 is not currently fully supported. You will also need an ArcInfo level license to run one of the hydrology modules. Spatial Analyst extension should be installed and activated on your computer. In addition, you must have Python 2.4 or higher, which is typically installed automatically as part of ArcGIS. Running InVEST effectively does not require knowledge of Python programming, but it does require basic to intermediate skills in ArcGIS.

InVEST 1.0 includes models for carbon sequestration, pollination of crops, managed timber production, water pollution regulation and sediment retention for reservoir maintenance. It also includes a biodiversity model so that comparisons and tradeoffs between biodiversity and ecosystem services can be analyzed. The next release of InVEST will include a suite of new ecosystem services: flood mitigation, agriculture production, irrigation, open access harvest and hydropower production. The tool is modular in the sense that you do not have to model all the ecosystem services listed, but rather can select only those of interest.

The User's Guide steps you through installing and running the tools, provides some of the theory behind each model and describes the input data requirements and output results. We also supply a set of sample data you can use to get to know the models and how they work.