Systematic atlasing in Hessequa – Report on the first cycle of seasonal monitoring

Abstract

Bird atlasing in the Hessequa region of the Western Cape has progressed beyond mapping to monitoring. During a three-year period within 2014/17, the U3A Stilbaai Bird Group upgraded the distribution maps using a strategy which aimed to even out coverage per grid cell, and achieve minimum mapping standards. In the two-year period December 2017 to November 2019, the group implemented a new strategy that would result in each of the 75 pentads in the Hessequa Atlas Area being atlased in each of the four seasons over a two-year period. Using a chessboard pattern to split the 75 pentads into two sets, the first set was atlased in summer and winter in the first year and autumn and spring of the second year. The second set was atlased in autumn and spring of the first year, and summer and winter of the second year. This paper reports the successful completion of the first monitoring cycle. Introduction The Second Southern African Bird Atlas Project (SABAP2) started in July 2007, with the objective of mapping the distributions of bird species in South Africa, Lesotho and Swaziland. This citizen science project has a clearly defined fieldwork protocol and uses spatial units called pentads which are five minutes of latitude north to south and five minutes of longitude east to west (Underhill 2016, Underhill & Brooks 2016). SABAP2 is now one of the longest running bird atlas projects ever, and the emphasis has shifted from the project being a snapshot of bird distributions at a point in time to a project which is measuring how distributions are changing in time. The initial focus on mapping in SABAP2 has shifted to a focus on monitoring (Underhill et al. 2017). Ornithology Figure 1. The overall boundary of the 75 SABAP2 pentads forming the Hessequa Atlas Area at the eastern end of the Overberg, Western Cape, South Africa (van Rooyen 2018). Van Rooyen & Underhill: Atlasing in the Hessequa Biodiversity Observations (2020) 11.3: 1–14 3 The U3A Stilbaai Bird Group (U3A Stilbaai 2015) adopted this citizen science project in 2014, and defined the “Hessequa Atlas Area” as an area consisting of 75 pentads (Figure 1) (van Rooyen 2018). The area coincides closely with the borders of the Hessequa Municipality which falls administratively within the Eden District; it lies at the eastern end of the part of the Western Cape popularly referred to as the Overberg (van Rooyen 2018). The chosen area lies between the Langeberg mountain range and the sea and the dominant land use is mixed agriculture (mainly barley, wheat, canola, sheep and cattle); the foothills of the Langeberg form the northern boundary and there is natural vegetation along the coast in the south (Plates 1–6). Atlas fieldwork started in October 2014; by November 2017 the Bird Group had submitted 539 full-protocol checklists, and visiting atlasers a further 200, and every grid cell in the area had achieved a foundational coverage of at least seven fullprotocol checklists (van Rooyen 2018). A “full-protocol checklist” requires a minimum of two hours of fieldwork (Underhill 2016). Van Rooyen (2018) described a strategy for shifting the focus of the U3A Stilbaai Bird Group from foundational coverage to seasonal monitoring in two-year cycles. This paper reports the progress towards meeting the targets between December 2017 and November 2019. It also describes overall progress with the project in the region, and considers the strategies in place to enable the project to achieve its monitoring targets. It compares checklists submitted by members of the Bird Group with those submitted by visiting atlasers.