About Traits

The Freshwater Biological Traits Database currently contains traits data for 3,857 North American macroinvertebrate taxa, and includes habitat, life history, mobility, morphology and ecological trait data. These data were compiled for a project on climate change effects on river and stream ecosystems. The traits data were gathered from multiple sources, which are listed on the web site under, "Data Source". Data gathering efforts focused on data that were published or otherwise well-documented by trustworthy sources, accessible, appropriate for the regions being studied, in a standardized format that could be analyzed or easily converted to a format that could be analyzed, and ecologically relevant to the gradients being considered.

Background Information

Click to learn more about and download the final report.The Freshwater Biological Traits Database was compiled for a project on climate change effects on river and stream ecosystems that was conducted by the Global Change Research Program in the Center for Public Health and Environmental Assessment (CPHEA), formerly known as the National Center for Environmental Assessment (NCEA), in the US EPA Office of Research and Development. For this project, long-term trend analyses were performed on biomonitoring data from Maine, North Carolina, Ohio and Utah to examine whether biological responses to changes in temperature and hydrology could be detected. One component of these analyses involved compiling and analyzing traits data for North American macroinvertebrate taxa found in lotic systems. Advantages of using traits data for these types of analyses are that they are less susceptible to taxonomic ambiguities or inconsistencies in long-term datasets; they can detect changes in functional community characteristics; and they vary less across geographical areas, which allows for larger-scale trend analyses across regional species pools.

For this project, data gathering efforts focused on data that were published or otherwise well-documented by trustworthy sources, accessible, appropriate for the regions being studied, in a standardized format that could be analyzed or easily converted to a format that could be analyzed, and ecologically relevant to the gradients being considered. The 14 data sources that have been integrated into the Traits database, along with information associated with these sources, are listed on the page, Traits - Data Sources and Metadata. The main sources are the USGS traits database (Vieira et al. 2006) and the Poff et al. trait matrix (2006). Also included in the database are thermal optima and tolerance data that were generated from weighted average or generalized linear model calculations that were performed on biomonitoring data from a number of different states. Weighted average inference is a simple, robust approach for estimating the central tendencies of different taxa, or in our case, optima and tolerance values (Yuan 2006).

Due to the substantial effort it took to gather all of this traits data into one place, we have integrated the traits data into one searchable database to make it available to everyone. The Traits Database currently contains location, habitat, life history, mobility, morphology and ecological trait data, along with tolerance calculations for temperature and flow. Data types vary, and include binary, categorical, and text notes entries. There are currently 11,912 unique records contained in Traits for 3,857 different taxa. Levels of taxonomic resolution vary.

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