Biodiversity

Methods 5.0

The Habitat Potential Index evaluates the characteristics of different land covers and managements that can support aboveground biodiversity.

Conservation Effects Assessment Project (CEAP-Wetlands) study of the Chesapeake Bay concentrates on the ecological benefits of conserving wetland areas in Delaware on July 7, 2008. Wetlands provide significant ecosystem services that include floodwater storage, water quality improvement, biodiversity support, and wildlife habitat. USDA photo by Alice Welch.

Introduction

Biodiversity is “the variation of life forms within a given ecosystem or field” (NRCS Conservation Basics. The challenge facing modern agriculture is balancing biodiversity conservation with productive land use. Land use change, particularly the conversion of natural ecosystems to cultivated land, has been identified as the primary driver of biodiversity loss globally (Lark et al. 2020; Newbold et al. 2016; Semenchuk et al. 2022). Growers can support essential wildlife habitat with key, field-level management practices and by preserving vegetative covers, wetlands, prairies, or other ecosystems on their land. Crop production on farms that support biodiversity can benefit from ecosystem services such as pollination by native species, pest control through predator populations, and nutrient cycling and reduced erosion to maintain soil fertility and reduce environmental losses.

Field to Market adapted the Habitat Potential Index (HPI) as a qualitative metric that can indicate ecosystem support for biodiversity across the managed acres enrolled in a Fieldprint Project. This metric aims to guide growers about how their management decisions influence wildlife habitat on their farms. Higher values are to be interpreted as higher realized potential.

Note

The term wildlife broadly encompasses non-domesticated species of plants and animals.

While the concept of biodiversity certainly extends to belowground ecosystems in the soil, the scope of the HPI is focused on aboveground biodiversity.

The HPI connects with other Field to Market metrics to provide a holistic sustainability assessment:

Land Use: Higher yields on existing farmland reduce pressure to convert natural habitats, supporting landscape-level biodiversity conservation through land sparing.

Water Quality: Many practices that improve water quality (buffer strips, cover crops, nutrient management) also enhance habitat potential.

Soil Conservation: Reduced tillage and permanent cover protect both soil and wildlife habitat.

Soil Carbon: Cover crops and reduced tillage can sequester carbon while providing wildlife benefits.

Background and Development

The HPI was developed through multiple phases of stakeholder engagement and scientific review. Phase I (2011-2012) involved creating a preliminary framework across all land cover types. The framework was refined during Phase II (2012-2014) through collaboration with Field to Market’s Biodiversity Subgroup and technical committees, streamlining the parameters to balance scientific rigor with practical implementation.

The original vision for the HPI included a comprehensive whole-farm biodiversity assessment with separate questionnaire modules for each land cover type: cultivated lands, forests, wetlands, grasslands, and surface waters. Each module would function independently while contributing to an integrated farm-level score.

However, implementation challenges emerged during the initial rollout in 2018. User feedback indicated the whole-farm approach was too complex, that answering all questionnaires was too time-consuming for grower participants. Technical implementation issues also arose, and limited time for testing and user education resulted in low adoption rates. Consequently, Field to Market decided to implement only the cultivated land module initially, leaving the door open for further metric revisions in the future.

Conceptual Framework of the HPI

Rather than measuring actual species counts or conducting biological surveys, the HPI evaluates the structural and functional characteristics of different land cover types that support biodiversity. This approach recognizes that land cover quality, composition, and management practices serve as meaningful proxies for biodiversity potential.

The HPI operates on several key principles that guide its implementation and interpretation:

Principle	Description
Current Status Focus	Evaluates the farm as it exists today, not against a pre-agricultural baseline
Grower Control	Emphasizes factors within the grower’s operational control and knowledge
Land Sharing	Promotes co-existence of agricultural productivity and biodiversity
Practical Application	Provides actionable information without requiring ecological expertise
Scientific Foundation	Based on established ecological principles and peer-reviewed research

HPI Components

The HPI consists of three primary components that work together to generate a comprehensive assessment of habitat potential:

1. Farm Composition

Farm composition refers to the acreage and distribution of various land cover types present on the farm. The HPI recognizes multiple land cover categories:

• Cultivated lands - Row crops and other agricultural production areas
• Edge-of-field areas - Buffer strips, field borders, grassed waterways serve as transition zones between intensive agriculture and natural areas
• Forests - Deciduous, evergreen, and mixed forest types that provide vertical structure
• Grasslands and savannas - Native and managed grasslands, pastures; offering open habitat for grassland-dependent species
• Wetlands - Natural and constructed wetlands support unique aquatic and semi-aquatic communities.
• Surface waters - Ponds, streams, and other aquatic features provide essential water resources and riparian habitat

Note

Each land cover type contributes differently to the overall habitat potential based on its inherent ecological value and management intensity. The Fieldprint Platform currently implements only the cultivated land module (HPI 0-10) of the comprehensive HPI framework .

2. Ecological Weighting Factors

The HPI assigns ecological weights to different land cover types based on their relative contribution to biodiversity support. These base weights reflect the concept of “naturalness” and capacity to support ecosystem services. The weights are assigned on a scale of 1 to 5, with higher values indicating greater ecological value:

Base Weight	Land Cover Types
5	Wetlands, surface waters, riparian areas
3-4	Mixed/deciduous/evergreen forests, native grasslands
2	Pastures, introduced grasslands, conifer plantations, buffer strips
1	Cultivated lands

These base weights are further modified based on regional ecological context. For example, native grasslands receive a weight of 4 in grassland-dominated ecoregions but 3 in forest-dominated regions, reflecting their relative ecological importance. Additional modifying factors include ecological scarcity (rare ecosystem types receive 0.5 additional points), conservation priority status, and development pressure from urbanization.

3. Ecological Quality Values

Each land cover type receives an ecological quality score (0-10) based on an aggregated assessment of individual HPI parameters. These parameters are categorized as either structural/functional (physical and biological characteristics) or management-based (human activities that influence habitat potential). Management parameters receive double weighting in the calculation to emphasize factors within grower control. The ecological quality value represents the realized habitat potential of a specific land cover relative to its maximum potential.

Cultivated Land Module Parameters

The Fieldprint Platform currently implements only the cultivated land module of the comprehensive HPI framework. The cultivated land module evaluates nine key parameters that influence habitat potential in crop production areas. Each parameter has been assigned a weight based on its relative importance to biodiversity, derived from USDA Natural Resources Conservation Service (NRCS) Environmental Benefits Scores and expert consultation:

Cultivated Land Module Parameters

Parameter	Description	User Inputs	Weight
Residue cover	Percentage of soil surface covered by crop residue after harvest	Tillage activities	35
Crop rotation	Diversity and sequence of crops grown over the rotation	Crop for each crop interval	31
Cover crops	Use of cover crops between cash crops	Add a cover crop activity	42
Nutrient management	Implementation of 4R principles (right source, rate, time, place)	Additional Data > Nutrient Management Indicate if nutrient management plan was followed, or check any 4Rs that applied.	19
Pest management	Options including Integrated Pest Management (IPM) practices	Additional Data > Pest Management Select the pest management strategy used.	31
Water conservation	Irrigation efficiency and water source accountability	Add an irrigation activity if applicable.	44
Drainage management	Tile drainage and water table management	Field Details > Tile drainage Conservation practices > Drainage Water Management1	26
Wildlife enhancements	Practices specifically supporting wildlife (flooding, nesting areas)	Additional Data > Habitat > Options provided foraging habitat provided breeding and/or nesting habitat	87 174 (if flooded rice)
Recent land conversion	Conversion from natural to cultivated land	Any conversions in past 5 years, previous land cover type.	-

¹ USDA NRCS Conservation Practice Standard 554, Drainage Water Management

Method

The HPI calculation follows a four-step process that integrates structural characteristics, management practices, and ecological weighting to generate a final percentage score.

1. Calculate Structural Score
2. Calculate Management Score
3. Calculate Eco-Quality Score
4. Convert to HPI

Step 1: Calculate Structural Score

The structural score accounts for recent land use changes that affect biodiversity.

For cultivated lands without recent conversion, the structural score equals 1. If conversion from natural habitat occurred within the past 20 years, the score is reduced based on the proportion of converted acres (\(A_c\)) from total acres (\(A\)) and the ecological difference between land types:

\[ Structural = 1 - \left( \frac{A_c}{A} \right) \left( \frac{|EV - EV^\prime|}{4} \right) \]

where \(EV\) = Original Ecological Value, \(EV^\prime\) = New Ecological Value

For example, converting 50 acres of native grassland (ecological value = 3) to cropland (ecological value = 1) on a 200-acre field:

Structural Score = 1 - (50/200) × (|3-1|/4) 
                 = 1 - 0.25 × 0.5
                 = 0.875

Step 2: Calculate Management Score

The management score represents the weighted achievement across all management parameters:

Management Score = Σ(Parameter Score × Parameter Weight) / Σ(Maximum Score × Parameter Weight)

For example, with the following practices:

• No-till (score = 1.0, weight = 35)

• Conventional rotation (score = 0.5, weight = 31)

• Cover crops on most acres (score = 1.0, weight = 42)

• Full nutrient management plan (score = 1.0, weight = 19)

• IPM with chemicals (score = 0.5, weight = 31)

• No irrigation (score = 1.0, weight = 44)

• No tile drainage (score = 1.0, weight = 26)

• Wildlife foraging habitat (score = 1.0, weight = 87)

Total Achieved = (1×35) + (0.5×31) + (1×42) + (1×19) + (0.5×31) + (1×44) + (1×26) + (1×87) = 284 

Total Possible = 35 + 31 + 42 + 19 + 31 + 44 + 26 + 87 = 315

Management Score = 284/315 = 0.902

Step 3: Calculate Eco-Quality Score

The eco-quality score combines structural and management scores, with management receiving double weight:

Eco-Quality Score = ((Management Score × 2) + Structural Score) / 3 × 10

Continuing the example assuming no land use change:

Eco-Quality Score = (0.902 × 2 + 1.0) / 3 × 10 = 9.35

Step 4: Convert to Final HPI Score

The final HPI score expresses realized habitat potential as a percentage:

Field Land Cover Score = Acreage × Eco-Quality Score × Ecological Weight Total Possible Score = Acreage × 10 × Ecological Weight HPI Score = (Field Land Cover Score / Total Possible Score) × 100

For a 200-acre wheat field:

Field Score = 200 × 9.35 × 1 = 1,870

Total Possible = 200 × 10 × 1 = 2,000 

HPI Score = (1,870 / 2,000) × 100 = 93.5%

Interpreting Results

HPI scores should be interpreted within the context of:

1. Regional considerations - Habitat potential varies by ecoregion and landscape context
2. Production requirements - Balances conservation with necessary agricultural productivity
3. Improvement trajectory - Focus on continuous improvement rather than absolute scores
4. Management flexibility - Recognizes constraints of climate, soil, and market conditions

Score Ranges and Meanings

HPI scores represent the percentage of realized habitat potential for the assessed land:

Score Range	Interpretation	Management Implications
>80%	Maximized habitat potential	Maintain current practices, consider minor enhancements
50-80%	Moderate realized potential	Good foundation with opportunities for targeted improvements
<50%	Significant improvement opportunities	Review all parameters for enhancement options

Factors Influencing Scores

Management practices that typically enhance HPI scores include maintaining high residue cover through reduced tillage systems, implementing diverse crop rotations with three or more crops, adopting cover crops across most acres, following comprehensive nutrient management plans, utilizing IPM strategies that minimize chemical inputs, implementing water conservation measures when irrigation is necessary, managing drainage water to reduce impacts, and providing specific wildlife habitat enhancements.

The relative impact of improvements varies by parameter weight. For instance, adding wildlife habitat enhancements (weight = 87) has greater scoring impact than improving nutrient management (weight = 19), though both provide ecological benefits. Similarly, implementing cover crops (weight = 42) offers more scoring benefit than drainage improvements (weight = 26).

Limitations and Considerations

Current Implementation Constraints

The HPI faces several limitations in its current implementation. The metric is currently limited to the cultivated land module in the Fieldprint Platform, preventing whole-farm assessment. It does not measure actual biodiversity, only habitat potential based on structural and management indicators. The focus remains on terrestrial wildlife, not addressing soil biodiversity or aquatic ecosystems beyond basic water quality considerations. The metric relies on user-reported management practices without field verification, and simplified scoring may not capture complex ecological interactions or site-specific conditions.

Practical Application Challenges

Users should consider practical constraints when interpreting HPI results. Some high-scoring practices may not be economically feasible for all operations. Regional climate and soil conditions limit management options regardless of biodiversity benefits. Market demands and supply chain requirements may restrict crop diversity options. The time lag between practice implementation and ecological response means improvements may not immediately translate to biodiversity gains. Local regulations or program requirements may mandate certain practices regardless of HPI scoring.

Proposed Revision

In 2023, Field to Market explored replacing the HPI with a new metric called the Wildlife and Landscape Diversity (WILD) Index. This proposal aimed to address member feedback requesting more comprehensive Integrated Pest Management (IPM) assessment, better support for edge-of-field practices, and incorporation of landscape context in biodiversity evaluation. The WILD Index underwent public comment from November 2023 through early 2024. While the proposal generated interest and valuable discussion and technical improvements, implementation was ultimately paused due to various technical and strategic considerations. The complete documentation, public comments, and revision materials remain publicly available.

Future Directions

Potential Enhancements

Several enhancements could strengthen the HPI’s effectiveness and applicability. Implementing additional land cover modules beyond cultivated lands would enable true whole-farm biodiversity assessment. Incorporating landscape context through remote sensing could account for surrounding habitat influences. Developing regional calibrations could better reflect local ecological conditions and species assemblages. Creating linkages with on-farm biodiversity monitoring could validate model predictions and refine scoring algorithms. Expanding the metric to include soil biodiversity indicators would provide a more complete ecological assessment.

Integration Opportunities

Future development could explore integration with emerging sustainability frameworks and technologies. Alignment with corporate biodiversity commitments and nature-positive targets could enhance supply chain sustainability reporting. Integration with precision agriculture technologies could enable field-zone-specific biodiversity management. Connection with ecosystem service valuation frameworks could quantify economic benefits of biodiversity practices. Incorporation of climate adaptation considerations could address biodiversity resilience under changing conditions.

Tables

Cultivated Land Parameter Scoring Options

Each parameter offers multiple response options that translate to scores between 0 and 1:

Residue Cover (HPI-3)

Option	Score
>30% residue (No-till, strip till, conservation tillage)	1.0
15-30% residue (Reduced tillage)	0.5
<15% residue (Conventional or intensive tillage)	0.0

Crop Rotation (HPI-4)

Option	Score
Crop to fallow rotation	1.0
Conventional rotation (2-3 crops)	0.5
Continuous single crop	0.0

Cover Crops (HPI-5)

Option	Score
Have a cover crop	1.0
Use on approximately half of crop area (No longer applicable in version 5.0)	0.5
Do not have a cover crop	0.0

Nutrient Management (HPI-6)

Receive 0.25 points for each of the 4Rs: right rate, right source, right time, right place.

Option	Score
Implement nutrient management plan OR all 4Rs	1.0
Three Rs	0.75
Two Rs	0.5
One R	0.25
None	0.0

Pest Management (HPI-7)

Option	Score
IPM strategies used to manage pests, primarily without chemical control	1.0
IPM strategies used to manage pests, including chemical control	0.75
Pest managed primarily using chemical control and additional site-specific techniques to reduce environmental risks of the pesticides	0.5
Pest managed primarily using chemical control	0.0

Water Conservation (HPI-8)

Option	Score
Crop not irrigated	1.0
Groundwater or source not connected to surface water	1.0
Surface water or alluvial groundwater (with conservation methods)	0.75
Surface water or alluvial groundwater (without conservation)	0.0

Drainage Management (HPI-9)

Option	Score
No tile drainage OR tile drainage with water management2	1.0
Tile drainage without management (poorly-drained soil)	0.5
Tile drainage without management (well-drained soil)	0.0

² Conservation Practice Standard 554, Drainage Water Management

Wildlife Enhancements (HPI-10)

Option	Score
Provide foraging AND/OR breeding/nesting habitat	1.0
Seasonal flooding (rice only)	1.0
None	0.0

References

Lark, Tyler J., Seth A. Spawn, Matthew Bougie, and Holly K. Gibbs. 2020. “Cropland Expansion in the United States Produces Marginal Yields at High Costs to Wildlife.” Nature Communications 11 (1): 4295. https://doi.org/10.1038/s41467-020-18045-z.

Newbold, Tim, Lawrence N. Hudson, Andrew P. Arnell, Sara Contu, Adriana De Palma, Simon Ferrier, Samantha L. L. Hill, et al. 2016. “Has Land Use Pushed Terrestrial Biodiversity Beyond the Planetary Boundary? A Global Assessment.” Science 353 (6296): 288–91. https://doi.org/10.1126/science.aaf2201.

Semenchuk, Philipp, Christoph Plutzar, Thomas Kastner, Sarah Matej, Giorgio Bidoglio, Karl-Heinz Erb, Franz Essl, et al. 2022. “Relative Effects of Land Conversion and Land-Use Intensity on Terrestrial Vertebrate Diversity.” Nature Communications 13 (1): 615. https://doi.org/10.1038/s41467-022-28245-4.