Rationale
This species is widespread, common and abundant in numerous protected areas within the assessment region. There are well over 10,000 mature individuals (an estimated 158,220â228,012 individuals in 2012 in Kruger National Park alone), and nearly all (if not all) subpopulations are stable or increasing to the extent that large-scale culls are necessary for many areas, which may form the foundation of a sustainable wildlife-based economy in these areas if managed properly. Similarly, the global population is estimated at almost 2 million, of which about 50% are on private land (stable or increasing) and 25% in protected areas (stable). There are no immediate threats to this species, although artificial selection for desired colour traits and/or deliberate hybridisation with Black-faced Impala (A. m. petersi) may compromise the integrity of the wild population if these subpopulations are used in translocations or to establish new subpopulations. However, its future is secure as long as it continues to occur in large, adequately protected populations.
Regional population effects: The species range is generally continuous through East and southern Africa, with only the Black-faced Impala being isolated from these former populations. There is likely to be movement within extensive wildlife regions to facilitate genetic mixing and there is the potential for dispersal across transfrontier boundaries.
Population trend
Trend
Population estimates are available for most of the Common Impalaâs current range. East (1999) estimated the total numbers of Common Impala at ~ 2 million. Although accurate estimates are not available, the subspecies is considered very common in the assessment region and occurs in almost all of the protected areas. For example, it is estimated that 158,220â228,012 individuals occur within the Kruger National Park alone (2012 distance sampling estimate) and the subpopulation is increasing (Ferreira et al. 2013). The species further occurs on several private game ranches throughout the assessment region. There are > 100 subpopulations within the assessment region. The only real isolation is between the KwaZulu-Natal subpopulations and those in the Lowveld (Mpumalanga, Limpopo) areas. Subpopulations are also fragmented by fencing but the constant trade in live animals of this species ensures gene flow is maintained. However, artificial selection for desired colour traits and/or deliberate hybridisation with Black-faced Impala (A. m. petersi) does pose a threat.
Threats
There are currently no major threats to the species. However, private landowners within the assessment region may be hybridising Common Impala with Black-faced Impala, which would compromise the genetic integrity of the Common Impala population. This has been identified as a severe threat to the Black-faced Impala (Green & Rothstein 1998). However, there was no evidence of natural hybridisation between Black-faced Impala and introduced Common Impala in Etosha National Park, Namibia (Lorenzen & Siegismund 2004). Similarly, selected breeding for colour variants by game ranchers may pose a threat to the genetic diversity of the Common Impala population though increased rates of inbreeding. Such threats should be quantified and monitored. Expanding human settlements, especially along protected area boundaries (Wittemyer et al. 2008), or around conservancies and game farms, may also result in increased poaching of the Common Impala within the assessment region (Lindsey et al. 2013).
Uses and trade
The trade in this species is local subsistence and local, national and international commercial trade in meat, live sales and trophy hunts. There is no anticipated negative effect on the population. Trade has had a positive effect through the reintroduction of the species into former parts of its range. Even though it is not a high-value species in the ecotourism industry, it is still utilised within this sector. However, where this subspecies has been introduced into areas beyond its natural range, it can subsequently prove difficult to remove, resulting in possible competition with other species and may ultimately become a threat to the indigenous fauna in these areas.
