Rationale
The Variegated Butterfly Bat is a widely distributed species across the continent, occurring in the northeastern areas of the assessment region with an estimated extent of occurrence of 135,809 km2. It occurs in many protected areas, including the Great Limpopo Transfrontier Park and the Lubombo Transfrontier Conservation and Resource Area, and thus habitats are connected across regions. While agricultural transformation and logging for fuelwood remain as threats, it is uncertain whether this is causing a net population decline as the species can also occupy human modified landscapes. It is a rare species, roosting in low numbers. Thus, we suspect there are fewer than 10,000 mature individuals, and may well be fewer than 1,000 mature individuals, within the assessment range. Systematic monitoring and research is urgently needed to determine population size and trend of this species, as it may qualify for a more threatened listing. Once more data are available, reassessment will be required. Primary interventions include protected area expansion and connection of riverine forest and woodland habitats through both continued transfrontier initiatives and stewardship or conservancy proclamations.
Regional population effects: As this species is present in the north eastern section of the assessment region as well as in southern Mozambique and in Zimbabwe, the population is suspected to be continuous across country borders. However, it has low wing loading (Happold 2013), and thus significant rescue effects are unlikely.
Population trend
Trend
This species is considered rare throughout its range but it may also be under-sampled as it is difficult to record due to its reticulated wings resembling dead leaves, rendering roosting bats well camouflaged (Happold 2013). It is therefore difficult to estimate the population size within the assessment region, but may be locally common in some areas. It is not well represented in museums, with over 40 specimens examined in Monadjem et al. (2010). As it roosts in foliage (often hidden among leaves or palm fronds), it does not form large colonies, usually singly or in pairs (Monadjem et al. 2010), and always fewer than 10 individuals (Rambaldini 2010). As such, there are suspected to be less than 10,000 individuals in total across its range, and possibly fewer than 1,000 mature individuals within the assessment region. Further data on density, colony size and occupancy is needed to evaluate this assumption.
Conservation
The Variegated Butterfly Bat occurs in protected areas such as in the Kruger National Park, Ndumo Game Reserve, Hluhluwe-iMfolozi Game Reserve and the iSimangaliso Wetland Park. No direct interventions can be put in place until more data on subpopulation size and trends, as well as local threat severity, is produced. However, the species would benefit from further protected area expansion, such as the planned link from Maputaland to the Lubombo Transfrontier Conservation Area (Smith et al. 2008). Identification and protection of key roost sites is also necessary.
Recommendations for land managers and practitioners:
- Report discoveries of new roost sites.
Research priorities:
- Further field surveys to discover new roost sites to inform protected area expansion.
- Monitoring of known subpopulations to establish population size and trend.
- Quantification of severity of local threats.
Encouraged citizen actions:
- Citizens can assist the conservation of the species by reporting sightings on virtual museum platforms (for example, iSpot and MammalMAP), especially outside protected areas.
