Our partners have invested more than $3 million in land cover data. While the cost of future data development efforts may fall with improvements in instruments, imagery and classification techniques, these costs could still be considerable.
The sustainability of long-term monitoring is a question of political will. Fiscal constraints could impact the temporal and spatial scale at which we assess land cover change. Monitoring every two to three years will require more funding, but monitoring every four to five years may not provide resource managers or elected officials with the timely information needed to support new policies.
Addressing this outcome will require metrics that account for the conversion of forests, farmland and wetlands and for changes in impervious cover. Each type of conversion presents unique monitoring challenges. Wetlands, for instance, cannot be accurately mapped with only the leaf-off and leaf-on aerial imagery typically collected by state and federal agencies. While techniques that use high-resolution data to assess landscape change with the precision needed to inform county-level decisions have advanced, they are not sufficiently established to distinguish between persistent and ephemeral changes in land cover.
Techniques to quantify the social and environmental impacts of land conversion must be explored and developed. Examining impacts to water quality, for instance, may require different approaches for nitrogen, phosphorus and sediment. Examining impacts to wildlife habitat may require regional habitat assessments for keystone species, species guilds or particular species of concern. Examining social and economic impacts will perhaps be the most challenging. Land conversions (other than those caused by extreme weather events) are often motivated by private and public interests, and their impacts are often characterized as overwhelmingly positive by the time they occur. Identifying negative impacts to the environment or to under-represented or at-risk communities challenges the status quo and risks becoming politicized.
Factors Influencing Progress
Several factors could impact our ability to improve our understanding of land conversion and its associated impacts across the Chesapeake Bay watershed. These factors have directly informed the management actions our partners will take to achieve the Land Use Methods and Metrics Development outcome.