Justification
This species is listed as Near Threatened on the basis that it is known from only two localities and, while both its extent of occurrence and area of occupancy are unknown its inferred habitat specialisation suggests that the area of suitable habitat within its range may not exceed 521 km2, and consequently it is unlikely to have an area of occupancy exceeding 2,000 km2, and potentially either occurs as a severely fragmented population or is prone to fragmentation following any disturbance, as it will be unable to colonise areas from which it is lost. At present, however, no immediate threats have been identified and there has been little land transformation, and it is consequently close to but does not fully qualify for listing in a threatened category applying criterion B2.
Geographic Range Information
This species is known only from the vicinity of the type locality, imprecisely described as "Vanrhynsdorp", on the west coastal plain of South Africa (Davis et al. 2020), and from a Sandveld area west of the Cederberg Mountains (Abdalla et al. 2018). This latter is likely to be imprecisely located, and the only known site in this area is a nearby patch of red sand (C. Deschodt pers. comm. 2023). In the Vanrhynsdorp area it has only been recorded in the same red sand area (A. Davis and C. Deschodt pers. comm. 2023). As such the two reported localities may refer to the same area of red sand. It may have a very restricted range, as the red sand microhabitat on which it appears to depend occurs in four patches in this region, with a combined area of 521 km2 (Davis et al. 2020). It has been recorded from 152 and 283 m asl (Davis et al. 2020); although these values are derived from imprecise localities, the actual elevational range is broadly similar (A. Davis pers. comm. 2023).
Population Information
Nothing is known of the population status of this species. As it is flightless and may be a habitat specialist, and consequently has limited dispersal ability, its occurrence may be highly fragmentary, but the known records are from the largest of the four red sand patches (A. Davis pers. comm. 2023). It can be reliably found in the Vanrhynsdorp locality on red sand (C. Deschodt pers. comm. 2023). It can be collected on every targeted search using overnight traps, though in small numbers.
Habitat and Ecology Information
Mean annual rainfall at the two known localities is 153 and 169 mm, while mean annual temperature is 18.4 and 19.1 °C (Davis et al. 2020). The only specimen with associated ecological data was collected in scrub on deep red sand in the Namaqualand Spinescent Grassland vegetation unit (Davis et al. 2020), and pig dung-baited traps set by C. Deschodt (pers. comm. 2023) have been set in the same area. It has been proposed that Macroderes species may be particularly associated with earth mounds known as heuweltjies, which are water-retaining, nutrient-rich structures that attract rodents whose dung may be a key resource for these beetles (Abdalla et al. 2018). These structures are however not present in this region. It is flightless and activity has been recorded from July to September, during the winter rainy season (Davis et al. 2020), with sampling efforts having been concentrated in August (C. Deschodt pers. comm. 2023). Related species have been seen active in or around snow (F. Roets pers. obs.), and this species may favour especially cold periods.
Threats Information
There has been very little land transformation in this arid region, with only 4% of the original native vegetation in Namaqualand Spinescent Grassland having been lost (Davis et al. 2020). There is evidence of strip ploughing in part of the sand patch in which this species has been found, followed by regeneration of natural vegetation at the known locality (C. Deschodt pers. comm. 2023). This form of ploughing would have retained some natural habitat, and this species will probably persist so long as suitable sand and moisture-retaining vegetation remain present (C. Deschodt pers. comm. 2023). Widespread cultivation would threaten this species. Although the area may be too arid to cultivate in the long term, short-term cultivation in a period of good rainfall could result in the rapid destruction of its habitat.
Dung beetles adapted to the cool, arid winter rainfall region of southwest South Africa and Namibia may be at elevated risk from the predicted impacts of climate change, which may result in temperature-driven changes to seasonal rainfall patterns and increase annual precipitation (Davis and Scholz 2020). This may facilitate the expansion of warm-adapted species from the northeast into presently unsuitable areas (Davis and Scholz 2020).
Use and Trade Information
There is no known use of or trade, and no commercial interest, in this species.
Conservation Actions Information
This species is not known from any protected areas, and statutory protection within its inferred range is very low (A. Davis pers. comm. 2023). Surveys of all patches of Namaqualand Spinescent Grassland and adjacent vegetation units are needed to clarify this species' distribution, occupancy patterns and ecological requirements (Davis et al. 2020). The status of the habitat should be monitored (C. Deschodt pers. comm. 2023).