Monitoring Levels Various monitoring options are available, some involving more of an effort than others. We will help you to select the most appropriate level of monitoring for your group. Visual Survey What A visual and physical evaluation of wetland conditions. Why Critical water pollution, habitat damage and “die off” can be detected through a visual survey. When Quarterly. Chemical Monitoring What An evaluation of wetland health based on water quality (e.g. salinity, pH, dissolved oxygen, temperature and settleable solids). Why Salinity concentration can affect the distribution and abundance of marsh organisms. The pH tells us if the water is acidic or basic and changes can indicate a pollution event. Oxygen and temperature are related to the respiration and biological activity or marsh organisms. Measurements of settleable solids are used to indicate an excess of sediment or other material in the water that can be a response to erosion. Solids can clog fish gills, deplete oxygen levels and suffocate sessile organisms. When Monthly. Biological Monitoring What An evaluation of wetland health based on the abundance and diversity of plants and animals. Why Changes in the composition of a plant and animal inventory can indicate habitat health. Healthy ecosystems usually contain great diversity. Typically, stressed habitats support less species with a greater number of individuals. Biological monitoring is also important in determining the spread of invasive species. When Quarterly.