Liwonde National Park Aerial Census

Liwonde National Park is the premier wildlife viewing destination in Malawi. The Park covers 538 square kilometres and is situated in the Upper Shire Valley, with the Shire River, draining Lake Malawi through Lake Malombe to the Zambezi, an important feature. The river spreads out over an increasingly wide floodplain which reaches up to 2km from the main channel in the Chinguni area in the south of the Park.

The grass-covered floodplains attract large numbers of elephant, waterbuck and impala and are the critical dry-season food resource for most of the wildlife of the Park. There is a large population of hippo in the park, and solitary animals or small groups are seen out grazing at all hours on the floodplains. Mopane woodland provides habitat for an impressive population of sable antelope for which Liwonde is renowned. Liwonde also supports the largest population of African elephant in the country.

Region: Liwonde National Park, Malawi

Aerial counts of population sizes of different wildlife species in protected areas can serve as useful tool to assist management decisions. The Liwonde National Park (LNP) faces a number of questions that can be resolved in the light of a better understanding of the animal numbers in the Park and their population trends. These include supplying animals for restocking other protected areas in Malawi, assessing the current biomass and stocking rate for various species, and evaluating suggestions for the introduction of large predators to enhance the tourism potential of the Park.

Malawi’s wild areas in general are under huge pressure and in steady and steep decline owing to the usual problems of demand for land and resources from a rapidly growing population. From a biodiversity point of view Liwonde is a jewel – within this relatively small area are mopane woodlands, brachystegia clad hills, huge floodplains, deciduous thicket and riverine vegetation. There are over 400 species of birds recorded in the Park. The future of the Park is hanging in the balance – poaching is rife and a management plan to protect a corridor to the north which allows the Park’s 400-odd elephant to migrate to and from a forest reserve that acts as a vital “pressure release valve” is in jeopardy. In 1987 there were probably over 40 lion in the Park; now there are none. The population of sable is rapidly diminishing and species such as warthog and impala are perversely increasing due to lack of predation.

In the interest of protecting the wildlife in the short and long term and guaranteeing the future of the Park, the Trust, Wilderness Safaris, IFAW and the Department of National Parks are working on increasing protection and determining the ideal carrying capacity of the Park and the ideal mix of game. The census is a first step to gathering the latter information.

While censuses have been taken in the past this has been irregular. Now, Liwonde needs solid and regular scientific data and having regular censuses are becoming a critical management tool for the effective running of the Park.

The aerial census of Liwonde National Park began in 2006 and has continued on an annual basis ever since. The Trust has been a pivotal part of funding these since their inception.

Annual Report 2015

Between 2006 and 2012, seven consecutive aerial total area censuses were conducted in Liwonde National Park. In October 2014, another was conducted using total area count methodology. The aircraft used was a two-seater Bathawk Type X 341 with 34.6 hours recorded; 14 sorties were flown over five days to complete the census, covering an area of 67 500 hectares. A systematic flight path pattern of east to west orientation and flight path spacing of 800 metres was observed during elephant, buffalo and sable counts that covered woodland and floodplain areas of the park. An irregular flight pattern was flown in preferred habitats for hippopotamus, waterbuck, impala and warthog – these species strongly favour water and floodplain habitats.

Wildlife distribution is clumped and there is a prevalence of significant daily movement to and from water. To minimise error induced by these characteristics, each specie was counted on a single day. Exceptions to this were antelope species occurring on the west bank of the Shire River, which are sufficiently isolated from the east bank by the River to exclude the possibility of significant overnight movement.

Increasing population trends were observed for the following species: elephant, buffalo, waterbuck, impala, warthog and hippopotamus. A marked declining trend was observed in the case of sable.

Snare poaching is identified as the most important threat to healthy wildlife populations in Liwonde National Park. As the largest elephant population remaining in Malawi, the area’s enormous inherent value is unquestionable in terms of the maintenance of biodiversity and safeguarding of the region’s hydrology.

Recommendations were made to improve the integrity of the boundaries, law enforcement, surveillance and future monitoring of wildlife populations in Liwonde National Park in an attempt to reverse the negative effects of illicit human activity in the Park.

2011 Census
The census and fence line survey were carried out over four days from 13th to 16th October 2011 before the rains started in earnest and when leaf cover was at a minimum. It is relevant to state that the area had received some light rainfall immediately before the census was conducted and some rain and strong winds were experienced during the census period. In spite of there being some turning of the colour of the grass in the woodland areas and some surface water being present away from the Shire River there was not a noticeable movement of those species utilizing the floodplain (waterbuck, impala and warthog) away from their normal, dry season habitat preference. Furthermore leaf cover remained at a minimum and visibility from the air was not compromised.

The methodology used in this census was very similar to that used in the 2009 and 2010 censuses. Modifications were made to the census methodology between 2009 and 2010. These were aimed at minimizing the possibility of double counting and maximizing counting efficiency. Differences in the methodology used between in 2010 and that used in 2011 are negligible.

A Bantam B22J conventional control, two-seat micro-light aircraft was used to conduct the survey taking advantage of the type’s low flying speeds (under 40 knots), manoeuvrability and superb visibility. This is the same type of aircraft that was used for the 2009 and 2010 aerial censuses of Liwonde National Park.

Comparison of the 2010 and 2011 census figures reveal a recorded increase, during the intervening period, in all of the populations of the seven species that are reliably counted from the air in Liwonde National Park:

• The recorded elephant population has increased by 141 individuals from 404 to 545 representing a 35% increase in one year.
• The recorded buffalo population has increased by 158 individuals from 348 to 506 representing a 45% increase in one year.
• The recorded sable population has increased by 40 individuals from 451 to491 representing a 9% increase in one year.
• The recorded waterbuck population has increased by 1157 individuals from 2002 to 3159 representing a 58% increase in one year.
• The recorded impala population has increased by 176 individuals from 1350 to 1526 representing a 13% increase in one year.
• The recorded warthog population has increased by 478 individuals from 791 to 1269 representing a 60% increase in one year.
• The recorded hippopotamus population has increased by 809 individuals from 1133 to 1942 representing a 71% increase in one year.

2010 Census
October 2010 saw the fifth consecutive annual aerial survey of Liwonde National Park funded by the Wilderness Trust. As with previous years the primary objectives of the survey were to determine the populations and the distribution of all of the large mammal species of the park. Such measures provide baseline information and can allow effective management decisions about the area to be made, including whether, and in what number, animals of certain species may be removed from the area to restock other protected areas in Malawi and further afield. Insight into myriad other aspects of the park’s ecology can also be gained and over time, provided such surveys are conducted at regular intervals and using similar methodology, comparisons can be drawn and trends identified.
In 2010 a number of additional objectives aside from those described above were identified: i) evaluate the extent of human encroachment into the corridor linking Liwonde National Park with Mangochi Forest Reserve, ii) evaluate the condition of the boundary fence, and ii) evaluate the extent of illicit use of the park using indicators easily observed from the air.

As in 2009, a Bantam B22J two-seat microlight was used to fly a total of 21.1 hours over four days to cover the approximately 55 000-hectare National Park and to survey the connecting corridor to the north.

Species
Elephant 404
Buffalo 348
Sable 451
Waterbuck 2002
Impala 1350
Warthog 791
Hippo 1133
Kudu 37
Reedbuck 17
Bushbuck 54
Duiker 2
Total 6589