Welcome to RoadSPLAT, an app that allows you to compare the costs and logistical effort of roadkill surveys across a range of survey designs and carcass persistence of focal taxa. The app has three components:

1. 'Survey Design', where the actual interactive analysis is run
2. 'Downloads', where figures and data from the analysis can be downloaded
3. 'Citations' where you can find information on the recommended citation of the app and associated paper published in the Journal of Environmental Management.

Survey Design

The Survey Design analysis takes a number of user defined inputs in the blue boxes (via numeric inputs and sliders) across four main input categories (speed and rates, survey distance, study duration, and budget). Each category is numbered and will allow you to sequentially select values that are relevant to the type of survey designs you wish to compare.

Survey speed is the average speed of the vehicle driven along the transects, labour rate is the cost per hour of employing staff who conduct the surveys, and the mileage rate is the cost per km of the vehicle used for the transects (note that mileage should include the combined cost of fuel and maintenance).

You then have a choice to select four different survey distances which represent the one-way distance of a roadkill survey transect.

There are three options for the study durations which indicate the total time available to complete the roadkill surveys.

The budget box gives an option to plot a red, dotted horizontal line which represents the maximum funds available for the surveys based on the sum of mileage and labour costs.

The primary outputs are two figures (in green boxes) which compare how costs change in relation to the mean carcass persistence across the various survey scenarios at either 75% or 50% detection rates (which arise from conducting an alternative to daily surveys). The costs of doing daily surveys (100%) are plotted in the figure below the comparative plot. For more detail on the methodology behind the analysis see the accompanying journal article here.

Downloads

In the Download tab you can download these figures (in PNG format) and the data that are used to generate them in case you want to make you own plots or interrogate some other aspects of the underlying data. Apart from the plot data, the comparative cost CSV has the following columns which give extra detail of for each survey design: recommended survey interval (days), total optimal number of surveys, total distance driven for the study, hours worked during surveys (both daily and total), and a breakdown of mileage and labour costs.

Citations

Here you'll find links to the peer-reviewed publication, the GitHub repo for the R Shiny app, and the recommended citation for both.

If you experience any problems feel free to contact us at science@ewt.org.za