First Atlas of Maps for Invasive Alien Species Within the Kruger National Park As in 2001

FIRST ATLAS OF MAPS FOR INVASIVE ALIEN SPECIES WITHIN THE KRUGER NATIONAL PARK AS IN 2001 No 01/02 2002 This report has been compiled by: B.W. Martin & L.C. Foxcroft Alien Biota Section January 2002 Issued by the Scientific Services Section Kruger National Park Private Bag X 402 Skukuza 1350 2 ACKNOWLEDGEMENTS We wish to thank the following persons for their assistance in the development and compilation of this report: The Kruger Park Marathon Club for donation of funds towards the purchasing of hardware and software to start the development of a GIS based database. The Working for Water programme for the sponsorship of a GIS technician post to work with the Alien Biota Section to further develop the GIS applications. The KNP GIS lab for providing data for use in the production of maps and other data. KNP personnel for recording plant distributions throughout the KNP. Dr Harry Biggs for kindly reviewing the manuscript and providing valuable advice. 3 CONTENTS HEADING PAGE 1. ..Introduction ………………………………………………………………. 4 2. Overall objectives ………………………………………………………….. 5 3. Description of area ………………………………………………..………. 7 4. Data capture ……………………………………………………………… 7 5. Species distribution data …………………………………………………… 7 5.1 Invasive alien plant species ………………………………………………... 8 5.1.1 Distribution of species throughout the KNP ………………………….. 8 5.1.2 Distribution of species in residential areas and restcamps …………….. 35 5.2 Invasive alien bird species …………………………………………………. 35 5.3 Invasive alien fish species …………………………………………………. 35 6. Summary and recommendations …………………………………………… 40 7. References ………………………………………………………………….. 41 8. Appendices …………………………………………………………………. 42 Appendix 1: Record form for sightings of invasive alien species Appendix 2: Determination of densities of alien plants Appendix 3: List of alien plant species found in restcamps and residential areas Appendix 4: List of plant species referred to in the report and status thereof 4 1. INTRODUCTION Invasive alien species have been present within the Kruger National Park (KNP) for over a century, however up until only a few decades ago were neglected in wildlife management systems (Foxcroft as in McNeely, 2000; Foxcroft and Richardson, in prep). Currently, approximately 360 alien plant species, 1 alien bird species and 3 alien fish species have been recorded in the KNP (Figure 1: Graph of increase of alien plants in the KNP). The aim of this document is to provide a point in time “snapshot” of the distribution of invasive alien species within the KNP for further reference use. The report makes use of historical data as well as data obtained from the KNP Working for Water clearing operations and other collections. One shortcoming however is the lack of information available regarding infestations in the terrestrial zones as most of the information currently available relates to infestations in the riparian zones. The mapping of the Opuntia stricta infestations is currently underway, however little is known regarding the establishment of other species in the terrestrial zones. This will need to be addressed in the near future and methods will need to be determined for the mapping thereof. Knowledge and understanding of the extent of the problem, of the management initiatives in place and of progress achieved, are essential to success in control programmes. For this reason, knowledge of the distribution and density of invasive species is paramount in determining priorities in clearing operations and to provide a baseline against which to measure success. Willing support is needed to gain momentum and continue extensive surveys and data collection over wider areas to provide a more complete picture of the invasion in the KNP. Figure 1: Increase in alien pl 400 ant species in KNP over time 350 300 250 200 5 Number150 of species 100 50 Obermeijer Alien Biota Section records 0 Codd MacDonald & Gertenbach 1936 Van Der Schjiff Fig. 1. From Foxcroft and194 Richardson,0 (In prep). 1944 1948 1952 1956 2. OVERALL OBJECTIVES 1960 The primary goal of this report is to provide an 1964 1968 invasive alien plants within the boundaries 1972 Years in this report are: 1976 1980 1984 This report will for the first time in the KNP provide a snapshot of the Invasive1988 species situation in the KNP, which will be av 1992 planners and decision makers. 1996 2000 Use in determining baseline costs of control options, as these can be determined from extent and density of weed infestations. of the KNP.indication Specific of the obj extent of infestations of ailable to researchers, rangers,ectives guides,provided for 6 Figure 2: Map of the KNP 7 3. DESCRIPTION OF AREA The KNP covers an area of approximately 2 million hectares and is the flagship National Park of South Africa. Seven major rivers flow through the park from the higher lying escarpment areas in the west and include the Crocodile, Sabie, Olifants, Letaba, Shingwedzi, Levuvhu and Limpopo Rivers (refer Figure 2). All of these rivers have their source outside the park and are therefore major vectors of propagule dispersal, from the densely infested areas outside the boundaries of the park. It is speculated that dispersal also takes place up catchments and with possible high levels of infestations in Mozambique and Zimbabwe the external threats create a complete island effect around the KNP, increasing possibilities of infestations from all sides. Annual rainfall decreases as one moves from south to north with the entire park receiving an average rainfall of 530mm, with two high areas of rainfall being Punda Maria (600mm/year) and Pretoriuskop (743mm/year) (Gertenbach, 1983). This is under the international average and would be classified as arid to semi-arid. However, the riparian zones provide a haven for the establishment of alien vegetation and are susceptible to invasion by plants such as Lantana camara, Ricinus communis, Chromolaena odorata and numerous others. Aquatic weeds such as Pistia stratiotes, Azolla filiculoides and Eichhornia crassipes also find suitable habitats in the dams and river pools. 4. DATA CAPTURE Data was captured using the Geographical Information System (GIS) Arcview 3.2 software. The KNP Alien Biota Section maintains this database and queries can be directed to [email protected]. In most cases, point features were recorded (i.e. single GPS points) with no measure of density. This data provides only an indication of distribution. Other data, collected from the Working for Water project and other sources include alien plant density, either per area or per contract. Appendix 2 includes the systems used to estimate plant density. 5. SPECIES DISTRIBUTION DATA The following section includes maps and tables related to the distribution and abundance of invasive alien species within and adjacent to the KNP. It should however be noted that the absence of a particular species on a figure does not necessarily signify absence of the species from that area. The data presented is according to records at this stage, which may be particularly weak from a number of areas or the species may have recently invaded the area and therefore has not been recorded on the system. 8 5.1 Invasive alien plant species The invasion of natural plant communities by alien plants is non-cyclical and permanent (Lotter, 1996) and the permanent loss of ecological diversity frequently leads to reduced stability and resilience within ecosystems. The establishment of more than 200 alien plant species in the KNP in the space of about four decades is at a rate which is alarming (Lotter, 1996). According to Versfeld, Le Maitre and Chapman (1998), Mpumalanga is one of the most heavily invaded provinces with approximately 16% being infested to some extent, the equivalent of 185 000ha being completely covered. The Olifants, Crocodile, Sabie and Sand rivers are heavily invaded by a wide range of species. 5.1.1 Distribution of species throughout the KNP The following section provides distribution maps of the internal and external threats to the KNP, Working for Water distribution and abundance data and maps of 23 invasive alien species (IAS) recorded in the KNP. These species represent the greatest threat to the biodiversity of the KNP. In Figure 3 areas were evaluated for number of species present and densities of all the species in that area. For each (density and species) an approximate score was allocated and then combined to provide the threat index for that region or the river (refer Table 1). Table 1: Indices used for calculation of threat index Density No. of species Density Classes Index Spp. Classes Index 1 – 2 1 1 – 5 1 3 – 4 2 6 – 10 2 5 – 7 3 11 – 16 3 8 – 11 4 17 – 25 4 12 – 15 5 26 – 35 5 16 – 20 6 36 – 48 6 21 – 25 7 49 – 64 7 26 – 30 8 65 - 80 8 In Figure 5 a similar method was used to determine the threat index, however due to very little information being available from these areas, assumptions were made based on personal experience of the authors regarding the infestations in these areas. 9 Below is a description of the additional information on the distribution maps: a) First recorded in KNP: This is the first documented record of this species in the KNP. b) Status in KNP: This is classified according to the threat posed by this species as well as historical spread of the species. Two categories (as described by Richardson et al, 2000) are mentioned in this report: Invasive: Naturalised plants that produce reproductive offspring, often in very large numbers, at considerable distance from parent plants, and thus have the potential to spread over a considerable area. Transformer: A subset of invasive plants which change the character, condition, form or nature of ecosystems over a substantial area relative to the extent of that ecosystem. c) Legal Status: This is classified according to the amendments to the regulations of the Conservation of Agricultural Resources Act, 1983 (Act no.

Load more