Rationale
(Changed due to New Information)
Within the assessment region, this species is known from only two records in Limpopo Province â collected 138 years apart. Its rediscovery in the western Soutpansberg Mountains in 2014 confirms its presence in the assessment region and adds a record to its sparse distribution in Zimbabwe, Mozambique and South Africa and northwards to Ethiopia. Its secluded roosts and high-flying habits means it is rarely collected by field surveys and suggests its distribution may be wider than currently known. Further studies are necessary to delimit distribution more accurately within the assessment region and this species should be reassessed once additional data are available. Although its roost sites are presumed to be granite precipices (unlikely to be transformed) and acoustic data suggest that the species is locally common, there is evidence to suggest continuing decline in habitat and habitat quality in the Soutpansberg (20% of woodland cover was lost from 1990 to 2006 in the Soutpansberg Mountains region due to fuelwood extraction). Thus we infer a potential ongoing decline in population and, as it is severely range-restricted (known from only one location), we list as Vulnerable D2. Should future research reveal a connection between the continuing decline in relevant habitat or habitat quality variables and mature individuals/colonies, this species could qualify for Critically Endangered B1ab(ii,iii,iv,v)+B2ab(ii,iii,iv,v).
Regional population effects: Unknown. As it is an open air forager, its dispersal capacity is assumed to be good. However, it has a disjunct distribution between the assessment region and the closest extra-regional subpopulation in Zimbabwe (Monadjem et al. 2010), and thus we assume no rescue effects are possible.
Distribution
Tadarida ventralis is sparsely distributed in the northeast of southern Africa, known from four sites in Zimbabwe, two sites in central Mozambique, one site in southern Malawi, and one site in northeast Zambia (Monadjem et al. 2010). It is one of the most poorly collected bats in southern Africa with just five specimens (of eight southern African records) examined by Monadjem et al. (2010), although 37 specimens are known from Kenya (Cotterill 2001).
Within the assessment region, it was originally described from the Transvaal in 1876, but no exact locality was given and no further specimens have been recorded in the former Transvaal since (Skinner and Chimimba 2005). Since 1876, despite extensive surveys in the former Transvaal Province (Rautenbach 1982), no further specimens of T. ventralis have been collected, leading to this species being regarded as a rare vagrant in South Africa (Monadjem et al. 2010). However, in January 2014 (138 years after its original discovery), following a massive rain storm, a male specimen of T. ventralis (DM 14680) was found dead on the ground outside the house of the manager of the Lajuma Research Centre located in the Luvhondo Private Nature Reserve in the western Soutpansberg (altitude 1,270 m).
It can easily be confused with other molossids (Taylor et al. in press). For example, Cotterill (1996) identified two specimens from Zimbabwe while re-examining a collection of Tadarida fulminans. Thus, its distribution within the assessment region and the rest of southern Africa may be wider than reflected by the available data. Further field surveys are needed to more accurately delimit its distribution within the assessment region.
Population trend
Trend
While some African molossids, notably Mops condylurus, are locally abundant, others are rare and poorly known, such as Tadarida ventralis. Their inconspicuous roosts and high-flying habits make them challenging to locate and study (Monadjem et al. 2010). Most records are collected serendipitously, thus precluding any analyses on population size and trends. This situation is exemplified by the current assessment where, after an extensive acoustic and capture survey of bats in the Luvhondo Private Nature Reserve, no additional specimens were recorded (Linden et al. 2014). However, based on acoustic surveys and subsequent comparisons of echolocation frequencies, the species may well be locally common in the Soutpansberg Mountains (Taylor et al. in press). Their choice of roosts in inaccessible cliff crevices and their high-flying behaviour makes conventional sampling through mist nets or harp traps difficult and may explain why they have not been recorded more often (Taylor et al. in press).
Threats
The potential threats facing this species need further investigation and quantification. As they occupy inaccessible habitats in mountainous and rocky areas, we suspect there is no significant population decline. However, research into their resource and habitat requirements may disprove this. The lower altitude habitats of the Soutpansberg Mountains are most susceptible to human impacts leading to habitat degradation due to overgrazing, bush encroachment, cultivation and denudation of large trees for firewood collection (Linden et al. 2014). Such disturbances could have negative impacts on this species and should be monitored.
Uses and trade
There is no evidence that this species is utilised in any way.
Conservation
The species is known to occur in the Luvhondo Private Nature Reserve and is thus at least partially protected. Further surveys are required to identify other areas in which it occurs to inform protected area expansion or biodiversity stewardship schemes. However, no direct interventions are possible currently until research has revealed basic data on its ecology and distribution.
Recommendations for land managers and practitioners: None
Research priorities:
- Capture and radio-tagging thus enabling the use of biotelemetric methods to locate daylight roosts.
- Field surveys to locate additional subpopulations.
- Habitat assessments of known roost sites to assess threat severity.
- Research into its foraging ecology to identify potential threats to key resources.
Encouraged citizen actions:
- Deposit any dead specimens with your local conservation agency or museum and alert the Lajuma Research Centre.
