Appendix H: More Ecosystem Services with InVEST

1 Purpose of this appendix

Appendix G introduced the logic of InVEST through a few core services: water yield, pollination, and carbon.

This appendix expands that view.

It shows how InVEST operationalizes additional ecosystem services that are central to:

  • risk reduction,
  • human health,
  • infrastructure protection,
  • fisheries,
  • and cultural value.

Together, these models illustrate how Earth–economy systems convert:

land and seascapes → biophysical processes → services → welfare

2 Flood risk reduction

The InVEST Flood Risk Mitigation model estimates:

  • how land cover alters runoff,
  • how water moves across terrain,
  • and how ecosystems reduce flood exposure.

Inputs include:

  • precipitation,
  • digital elevation models,
  • soil permeability,
  • land cover,
  • locations of people and assets.

Conceptually:

Runoff = f(Precipitation, Soil, Slope, LandCover) FloodRisk = Runoff × Exposure × Vulnerability

Vegetation:

  • increases infiltration,
  • slows overland flow,
  • reduces peak discharge.

Outputs:

  • maps of flood depth and extent,
  • avoided damage due to ecosystems,
  • risk metrics for downstream communities.

Earth–economy use:

  • evaluate upstream restoration,
  • price flood protection,
  • compare gray vs green infrastructure,
  • internalize disaster risk into planning.

Flood regulation turns forests and wetlands into capital assets.

3 Sediment retention and water quality

The InVEST Sediment Delivery Ratio (SDR) and Nutrient Delivery Ratio (NDR) models estimate:

  • erosion from each pixel,
  • transport downslope,
  • delivery to streams,
  • and export to downstream waters.

Core logic:

Erosion = f(Rainfall, Soil, Slope, LandCover) Export = Erosion × Connectivity

Vegetation:

  • anchors soil,
  • traps sediment,
  • filters nutrients.

Outputs:

  • sediment and nutrient export maps,
  • loads by watershed,
  • avoided pollution due to land cover.

Earth–economy use:

  • link deforestation to reservoir siltation,
  • connect farming practices to water treatment costs,
  • evaluate land-based pollution policy,
  • quantify upstream–downstream externalities.

These services transform hillsides into infrastructure.

4 Coastal protection

The InVEST Coastal Vulnerability model estimates:

  • exposure to waves and storm surge,
  • attenuation by reefs, mangroves, and marshes,
  • relative risk along coastlines.

Inputs:

  • bathymetry,
  • wave climate,
  • shoreline type,
  • habitat distribution,
  • sea-level rise scenarios.

Conceptually:

Exposure = f(Waves, Surge, Slope) Protection = g(HabitatType, Width, Location) Risk = Exposure − Protection

Outputs:

  • shoreline risk indices,
  • changes under habitat loss or restoration,
  • spatial patterns of protection.

Earth–economy use:

  • compare seawalls vs mangroves,
  • value reefs as protective assets,
  • integrate coastal ecosystems into adaptation plans,
  • couple climate risk with land-use decisions.

Here, ecosystems replace concrete.

5 Marine fisheries and habitat

The InVEST Fisheries and Habitat Risk Assessment models estimate:

  • habitat quality,
  • exposure to stressors,
  • population dynamics,
  • and harvest outcomes.

Inputs:

  • habitat maps,
  • stressor layers (e.g., trawling, pollution),
  • life-history parameters,
  • management rules.

Conceptually:

Population_{t+1} = Population_t + Recruitment − Mortality − Harvest Recruitment = f(HabitatQuality)

Outputs:

  • biomass trajectories,
  • sustainable harvest estimates,
  • risk scores by habitat.

Earth–economy use:

  • evaluate marine protected areas,
  • link habitat degradation to food supply,
  • assess long-run wealth in fisheries,
  • design harvest rules that preserve stocks.

Fish become renewable capital with memory.

6 Recreation and cultural services

The InVEST Recreation model estimates:

  • visitation patterns,
  • based on accessibility,
  • attractiveness,
  • and population proximity.

Inputs:

  • land cover,
  • protected areas,
  • roads and cities,
  • geotagged visitation data.

Outputs:

  • spatial patterns of recreation demand,
  • visitation indices,
  • changes under land-use scenarios.

Earth–economy use:

  • integrate tourism into regional planning,
  • value parks and green spaces,
  • connect urban design to well-being,
  • reveal non-market benefits.

This makes experience visible.

7 From service maps to system behavior

Each of these models produces:

  • spatially explicit service supply,
  • under alternative land or climate scenarios.

Earth–economy models then:

  • translate services into productivity, risk, or welfare,
  • propagate changes through markets,
  • alter land rents and behavior,
  • update future land patterns.

For example:

Forest restoration → Flood risk reduction (InVEST) → Lower expected damages → Higher effective productivity → Higher land value downstream → Changed development patterns → New land-use equilibrium

This is a feedback loop.

8 Why many services matter

A single ecosystem often provides:

  • carbon storage,
  • flood protection,
  • water filtration,
  • habitat,
  • recreation.

Policies that optimize one service can:

  • undermine others,
  • or produce co-benefits.

Only multi-service modeling reveals:

  • tradeoffs,
  • synergies,
  • and hidden costs.

Earth–economy modeling requires:

A vector of services, not a scalar.

9 Exercises

  1. Service portfolio.
    Choose one landscape (coast, forest, watershed, city fringe).
    List at least four ecosystem services it provides.

  2. Tradeoff design.
    Pick one service and propose a land-use change that increases it.
    Identify one other service that might decline.

  3. Coupling chain.
    Write a chain linking a land policy to:

    • an InVEST service output,
    • an economic outcome,
    • and a long-run stock change.

InVEST shows that ecosystems are not “background.”

They are:

  • pipes,
  • buffers,
  • pumps,
  • filters,
  • and factories.

Earth–economy modeling is what happens
when those machines enter the economy.