Brief overview of the natural history of Gonarezhou National Park
Gonarezhou National Park (GNP) is one of the 11 areas designated as a national park in Zimbabwe. GNP is situated in the south-eastern Lowveld of Zimbabwe, and occupies a total area of 5,053 km².
The mean annual rainfall of the area is 466 mm, most of which falls between November and March. Two severe droughts have occurred since 1961 and the 1991/92 drought led to the death of large numbers of wildlife. Temperatures range from an average of 27ºC in June to 36ºC in January. The park experiences a short dry winter season in June and July with temperatures below 30ºC and a hot wet summer season from November to April when temperatures exceed 40ºC The remaining months are hot and dry periods which precede and follow summer rains.
The landscape is scenic as a result of various sandstone incisions. The spectacular Chilojo Cliffs are more than 180m high and are a result of the river incision of the sandstones. Perennial and temporal pans are also a common feature of the sandstone plateaus. Steep rocky gorges with falls and rapids characterize the banks of the Save and Runde rivers. Noticeable peaks in the north are the Makamandima (578m) and Mutandahwe (571m) and in the south is Nyamutongwe (516m). The Save Runde junction is 165m above sea level and is the lowest point in Zimbabwe.
There are four main internal drainage basins in the Gonarezhou – Save, Runde, Guluwene/Chefu and Mwenezi. The Save and Runde rivers all drain into the sea via the Save, and the Guluwene and Mwenezi basins are part of the greater Limpopo catchment.
The pan system in the Gonarezhou is quite extensive. Apart from the two pans near the Save/Lunde junction (Tembwahata and Machaniwa) there are a number of larger pans which hold water well into the dry season. No artificial water is supplied for wildlife, with the exception of two historical weirs at Massasanya and Benji. It is part of the recommendations of the revised general management plan that historical artificial game water supplies are not re-established, in line with the adopted management policy of minimum interference in natural systems.
The vegetation of Gonarezhou is typical of the semi arid Colophospermum mopane zone, and consists predominantly dry deciduous savanna woodlands. Physiognomic types are woodland and woodland savannah (59%), scrubland (40%) and savannah grassland (1%). The plant checklist for the park includes 924 species from 118 families and 364 genera, with 265 trees, 310 shrubs, 55 woody climbers and 137 grasses. The list is regarded as incomplete as no systematic survey has been undertaken.
Fifty fish species have been recorded in Gonarezhou, primarily from the Save and Runde Rivers, but recent declines in water quality and flow patterns of the major rivers may have reduced this number. The killifish Nothobrancius fuzeri has historically been only found in pans of the Guluene/Chefu catchment, making it a Park endemic, but recent findings seem to suggest that its distribution also extends into the drainage system downstream into Mozambique. The Park remains it's type locality however, and probably contains the core of it's range. Other noteworthy species include lungfish that occur in seasonal pans in the Guluene/Chefu catchment, and Zambezi Shark and Small-tooth Sawfish have historically been recorded at the Save/Runde confluence.
The herpetofauna of Gonarezhou is unusual in Zimbabwe, as it includes many species which typically occur on the East African coastal plain. Reptiles and amphibians, being poikilothermic and less mobile than higher animal groups, are good indicators of bio-geographic boundaries, and their occurrence in Gonarezhou illustrates the bio-geographic importance of the Park. The Gonarezhou species list includes about 6% of the Southern African endemics and 14 species of special conservation interest
The bird checklist of 400 species includes a further 92 species regarded as `likely to occur’. The bird list includes 13 species that are rare or of limited distribution and of conservation interest. The scrub mopane areas of the park are one of the more significant breeding sites for the Lappet faced vulture in southern Africa.
A total of 89 species of mammals in 71 genera and 31 families have been recorded from the Gonarezhou. A further 61 species, mostly insectivores or small rodents are likely to occur. Most of the work on mammals was carried out in the 1960s and 1970s and there is a need to re-evaluate some of the collections. The Yellow Golden Mole and Cape Hare are only known from Gonarezhou in Zimbabwe, and the red squirrel only occurs in the southeast Lowveld of the country.
Latest estimates for large mammals in the Park are: Impala 12 347, kudu 2 564, buffalo 4 425, zebra 1 685, nyala 258 (Gonarezhou is the only place in Zimbabwe where nyala are found in significant numbers), wildebeest 1 416, eland 384 and giraffe 473. The results of all surveys since 1993 (the last management offtake) implies that the Gonarezhou elephant population is increasing at a mean annual rate of 5.9 %, and that the current population estimate of 10 151 is the highest ever recorded.