Heteronitis castelnaui has been assessed as Least Concern since it shows a large extent of occurrence and extensive area of occupancy. Although its range has become somewhat fragmented as a result of its association with the dung of monogastric herbivores (particularly elephants) whose ranges have become equally fragmented, it is afforded protection in many game reserves which also protect elephant populations. Therefore, it is unlikely to be threatened at present.

This species is widely but patchily distributed in savannas from East to southern Africa, primarily where monogastric herbivores are still present. Locality records are largely centred on game reserves (Davis et al. 2020). Records are known from northern areas of Namibia, Botswana and South Africa, and from Zimbabwe, Mozambique, Angola, Zambia, Kenya and Tanzania, with unvalidated reports also from Rwanda and the Democratic Republic of the Congo (Davis et al. 2020, A. Davis pers. comm. 2023). It has been recorded between 55 and 1,448 m asl. (Davis et al. 2020).

There are no quantitative population data available for this species. However, the species is still frequently observed, but primarily in elephant dung (Australian CSIRO 1970-1986, unpublished records).

Modern collection records for this large-bodied, night-flying, tunnelling species are almost entirely restricted to game reserves or other areas where elephants are still present (Australian CSIRO 1970-1986, unpublished records). The only exception, from the 1970's, is a single record of one individual from Buffelsdoorn near Tshwane/Pretoria, South Africa, which was collected from cattle dung in an area where there were a number of donkeys (Davis et al. 2020). This indicates that the species was, at the time, still present and maintaining a probably very small subpopulation distant from the nearest reserve. Other than individuals collected to light, the species has been recorded almost entirely from the coarse-fibred dung of monogastric herbivores, primarily elephant, but also white and black rhinoceros, horse and zebra (Australian CSIRO 1970-1986, unpublished records). Records summarised by Davis et al. (2020) include a single record from omnivore (warthog) dung, and three from ruminants (cattle). Although it has been recorded from grassland and sand most records are from dry to moist open woodland savanna on finer-grained clay loam or sandy loam. Flight activity is crepuscular in southern Africa, and occurs primarily during the summer rainy season (October to May) (Davis et al. 2020).

This species has been recorded from a wide range of savanna ecoregions including from north to south: Northern and Southern Acacia – Commiphora bushlands (WWF Ecoregions AT0711, AT0716), Victoria Basin forest savanna mosaic (AT0714), Serengeti Volcanic grasslands (AT0704), Central Zambezian miombo woodlands (AT0721), Zambezian and mopane woodlands and Angolan mopane woodlands (AT0702, AT0725), Zambezian Baikiaea woodlands (ATT726), savanna at the inland edge of the KwaZulu-Cape coastal forest mosaic (AT0116) (ecoregions based on Olson et al. 2001).

Some environmental characteristics for 80 locality records are as follows: mean annual rainfall between 435-1,300 mm; and mean annual temperature between: 18.1-27.3 °C.

Despite its widespread distribution in the east and southeast savannas, this species now shows a severely localised occurrence. This is due to the range fragmentation experienced by large non-ruminant (monogastric) herbivores to whose dung this species is specialized, particularly elephant (IUCN SSC African Elephant Specialist Group 2007). The large number of records from dry savanna may be an artefact of how the modern range of savanna elephants has largely contracted onto less agriculturally-desirable dryer climatic regions.

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There are no species-specific conservation measures in place for this species. The majority (82%) of records between 1971 and 1986 were taken from reserves that preserve monogastric herbivore populations, with records far from reserves apparently being remnant subpopulations that survive at low densities (Davis et al. 2020). The conservation of this species is linked to that of elephants, which are mainly restricted to game reserves or to the least populated regions of Africa. However, it is probable that no further action is required at present other than to continue the protection of elephants in the many game reserves and national parks in which this species occurs, e.g. Kruger, Umfolozi/Hluhluwe in South Africa, Hwange in Zimbabwe, Chobe in Botswana, Bicuari in Angola, Etosha in Namibia, Gorongosa in Mozambique, Masai Mara and Meru in Kenya, and Serengeti in Tanzania. It has been observed to benefit from rhinoceros reintroduction, e.g. reserves near Thabazimbi, South Africa (Davis et al. 2020).