Trend Analyses

To aid in conservation-related decision making, we developed trend analyses for each of Texas' freshwater species (when sufficient data were available).  Methods and other details can be found in this report. The resulting plots were produced using our tracks 1 and 2 datasets, and are still being developed. We expect them to be greatly improved with more data (track 3).

A publication (Buckwalter et al. 2018; see citation below) appeared online (16 November), that provided a new quantitative method for detection of trends of expansion or contraction of range-size for freshwater species based on collections data much like that of FoTX.  Their workflow used accessible open-source tools, and appeared to be readily adaptable for implementation in the FoTX website. We quickly explored application of their methods to the FoTX data, and found the results promising. We developed Python code (available on request) that automates Buckwalter et al. (2018)-like analyses of the entire online FoTX database, accessing the online copy of the data directly.

Our first version of these can be seen here.

An example of one the trend analyses for Fundulus chrysotus that indicates a steadily increasing detections per HUC (DPHS) over an extended time frame together with general (perhaps mostly southward and western) expansion.

Buckwalter, J. D., E. A. Frimpong, P. L. Angermeier, and J. N. Barney. 2018. Seventy years of stream-fish collections reveal invasions and native range contractions in an Appalachian (USA) watershed. Diversity and Distributions 24(2):219–232.