Data and code for "Report on the criteria for data quality and species characteristics for estimating species status and trends" (Western Cape case study)

Occurrence data in the Global Biodiversity Information Facility (GBIF) have various limitations and biases, due in part to biases in survey effort. Therefore, analyses that use these data to estimate biodiversity status and trends can be misleading. This is the data and code for an analysis to establish the necessary conditions for ensuring the accuracy of estimates on biodiversity status and trends. The data and code are specifically for a case study on the Western Cape Province of South Africa. It compares results obtained when analyses use unstructured cube data from GBIF, with those from analyses using data from structured monitoring programs, which are designed to minimise biases and errors and provide a largely accurate representation of biodiversity. The analysis focuses on birds in the Western Cape. The structured data are from the Southern African Bird Atlas Programme 2 (SABAP2). The analysis is performed for the Western Cape and for the area of the Western Cape where the Hessequa Systematic Atlasing Subproject is undertaken (near Stillbaai). SABAP2 uses a pentad grid - grid cells at a 5-minute2 spatial resolution (~ 8.2 km2 in southern Africa). The analysis is performed at pentad resolution, and at quarter-degree grid cell resolution (QDGC) - nine pentads fit into one quarter-degree grid cell (15 min2) This analysis forms part of the work of task 4.5 of the B-Cubed project.