The Conservation Assessment and Prioritization System (CAPS) is a computer model and sophisticated approach to assessing the ecological integrity of ecosystems. It is being used as a level 1 assessment methodology as part of a comprehensive wetlands assessment and monitoring program for Massachusetts. When credible models of ecological integrity can be developed we use them to get a comprehensive assessment of all Massachusetts wetlands and use it to guide field-based assessments (rapid or intensive) and policy/management to maintain or improve wetland condition.

For the past several years we have been using data collected in the field to compare the Indices of Ecological Integrity (IEI) calculated by CAPS with biological field data collected in streams, forested wetlands, salt marshes, and, more recently, shrub swamps. From these field data we have been able to calculate robust Indices of Biological Integrity (IBIs) that correspond to IEI gradients for streams and forested wetland, but not salt marshes. Salt marshes are probably the most threatened wetland type in Massachusetts and are particularly vulnerable to the effects of sea level rise.

We have several possible explanations for why we have not yet been able to correlate CAPS IEI scores with field indices of salt marsh condition. Any, all, or various combinations of factors may be affecting our ability to model ecological integrity or assess condition in the field for salt marshes. However, we believe that the main reason may be that the CAPS IEI model for salt marshes lacks metrics for important salt marsh stressors related to sediment dynamics, effects of increased nutrient loading on peat accretion, changes in marsh elevation relative to sea level rise, crab herbivory, and crab burrowing effects on peat density and stability. We have engaged in a project to investigate alternative ways of assessing salt marsh condition and vulnerability focusing on physical indicators of marsh condition and plant stress/productivity.

Field work in salt marshes is difficult because tide cycles affect our ability to access interior portions of marshes and to see/evaluate marsh characteristics due to ever changing water levels. Remote sensing (satellite imagery; aerial photographs) offer some potential for assessing salt marsh characteristics. However, these data may not be available at stages in the tide cycle when specific characteristics need to be assessed, such as high tide for assessing high marsh flooding or low tide for assessing creek bank stability.

We propose to investigate the use of unmanned aerial systems (UAS) to collect data when timing is critical and test the potential of using various sensors to assess vegetation health/stress and physical characteristics of salt marshes. These data will be calibrated and assessments validated using data collected on the ground, and will be used to calibrate and test other remotely sensed data (satellite and aerial photographs). The goal is to use UAS technology as part of a nested approach to remote sensing (also including satellite data and aerial photographs) to assess the physical and perhaps biological (e.g. plant stress) condition of salt marshes.

Once a system has been developed for assessing salt marsh condition using remote sensing, perhaps supplemented by limited ground data collection, it will be used to assess a large number of sites across the full range of salt marshes in Massachusetts. From these data we will use landscape-scale modeling to create CAPS metrics for characterizing stressors affecting salt marshes and create an IEI model for salt marshes that reflects biological and physical condition as evaluated in the field.

It is expected to take 4-8 years to complete this work. In this first phase of the work we are focusing on the exploration, refinement and calibration of remote sensing using UAS in order to assess salt marsh condition with respect to physical degradation, flooding and plant stress.Implement via ground-based surveys, a classification system for salt marsh vegetation, water features and patches of bare ground, and document areas of marsh stress and degradation (e.g. creek widening, bank instability, crab herbivory, areas of high crab burrow density, marsh subsidence, and unexplained salt marsh dieback)