INVERTEBRATE STUDY FOR PORTION 62 OF THE FARM WITPOORTJIE 177-IR, PROVINCE

by

V.C. VAN DER MERWE BSc Entomology, MSc Conservation Biology

Commisioned by Envirogaurd

December 2018

V.C. VAN DER MERWE EMAIL: [email protected] P.O.BOX 72 CELL: 074 166 0410 HAENERTSBURG 12 DECEMBER 2018 0730 ,

Invertebrate Assessment – Ptn 62 Witpoortjie 1 To Envirogaurd

INVERTEBRATE STUDY FOR PORTION 62 OF THE FARM WITPOORTJIE 177-IR, GAUTENG PROVINCE

We have the pleasure in submitting herewith our report as requested and as per your correspondence and appointment dated 11th November 2018. This study has been carried out in accordance with the provisions of Regulations gazetted in the Government Notice No R1183 of 6/9/1997 for the Department of Nature Conservation, of Gauteng Province, and also DEAT (2005) Guideline 3: General Guide to the Environmental Impact Assessment Regulations, 2005, Integrated Environmental Management Guideline Series, Department of Environmental Affairs and Tourism (DEAT), Pretoria.

The aim of this report was to provide the client with a description of potential status of Red Data Invertebrate species and habitat that could be potentially suitable for the presence of these species on Portion 62 of the Farm Witpoortjie 177-IR.

A concerted effort was made to locate four invertebrate species of conservation concern, including three species (Lepidochrysops praeterita, Chrysoritis aureus and dentatis) and one cetonid (Ichnestoma stobbiai). These species were not observed during the survey. The vast majority of the site consists of open grasslands and old fields that has been heavily invaded by anthropogenic, pioneer and exotic plant species. These areas are totally transformed and no natural vegetation remains. Three seasonally inundated depressions on the eastern portion of the site constitute the only sensitive habitat in the survey area.

Invertebrate Assessment – Ptn 62 Witpoortjie 2 CONTENTS

EXECUTIVE SUMMARY…………………………………………… 2 INTRODUCTION…………………………………………………….. 4 STUDY AREA……………………………………………………….. 6 MATERIALS & METHODS………………………………………… 12 RESULTS…………………………………………………………….. 14 DISCUSSION………………………………………………...………. 20 RECOMMENDATIONS…………………………………………….. 23 REFERENCES………………………………………………………. 26

Invertebrate Assessment – Ptn 62 Witpoortjie 3 INTRODUCTION

Biodiversity is the variability among living organisms on earth, including the variability within and between species and within and between ecosystems. The biodiversity of Gauteng is under constant threat from human settlement and societal development. Natural land is degraded and transformed by the rapid expansion of human settlements, such as residential areas, mines, manufacturing plants, transport and agriculture, that have an ever-increasing demand for space. The loss, fragmentation and degradation of natural habitat through urbanisation and an increase in human population numbers, represent the greatest threats to rare and endangered invertebrate species in Gauteng.

Sustainable development is an evolving concept, which is continually being redefined and reinterpreted and should form the basis of the planning processes of new developments. Reducing the burden of environmental impacts is necessary if development is to become sustainable. The process of planning new developments should be based on scientific, ecological principles and used as a planning tool to promote sustainable development by integrating environmental considerations into a wide range of proposed actions. Development planning must be intended to ensure that development proposals do not undermine critical resource and ecological functions, by improving the way these environmental resources are utilised, or the well being, lifestyle and livelihood of the communities and peoples who depend on them.

Invertebrates dominate terrestrial and freshwater ecosystems, with being the most speciose class, comprising more than 75% of all known species in the Kingdom. Insects and arachnids form part of the diverse and essential natural processes that sustain biological systems. The -plant interaction is the most common biotic interaction on Earth, and indeed, our present ecosystems would not function without these invertebrates. The worldwide Red List of Threatened Species (http://www.redlist.org/info/tables/table1) contains approximately 560 insects. This is a meagre 7% of the faunal list, which when one consider that insects make up over 70% of the worlds fauna, is tremendously negatively biased. In a study carried out by Black and Vaughn (2003), it was noted that of the world’s insects, very few groups have been assessed on a worldwide scale. Approximately 10% of Swallowtail , for example, are considered globally threatened. Based on a mathematical model, McKinney (2003), predicted that 10% of all butterflies were threatened contrasting to the 1% currently listed. At National levels, figures between 10% and 34% are given for the number of threatened indigenous insect species, suggesting that the overall number of threatened insects could be in excess of 100, 000. Globally countries such as Australia, France, Spain, the United

Invertebrate Assessment – Ptn 62 Witpoortjie 4 States and South Africa have among the highest numbers of threatened invertebrates. This is however, more a reflection of the effort made by these countries to assess their biodiversity and hence distinguish those that are threatened rather than a true overall indication.

Insects have an enormous functional value because of the numerous individuals and the great intra- and interspecific variety. The ecological importance of this great variety of insects makes them valuable to assess disturbances or environmental impacts. A sound knowledge of is crucial to the conservation and management of ecosystems because a skewed focus only on the larger organisms will misrepresent ecosystem dynamics. The lack of human appreciation of the importance of invertebrates and their general disregard and dislike, coupled to the fact that only about 7-10% of insects are scientifically described, must be overcome to realistically conserve biodiversity.

Photograph 1. The majority of the site has been subject to heavy overgrazing.

Invertebrate Assessment – Ptn 62 Witpoortjie 5 STUDY AREA

Figure 1. Locality map of the proposed Witpoortjie site.

Invertebrate Assessment – Ptn 62 Witpoortjie 6

Photograph 2. The Witpoortjie site is dominated by Tsakane Clay Grassland in various stages of transformation and degradation. Situated within the lower-lying areas as well as shallow depressions are seasonally inundated pans.

The Witpoortjie site is situated within the East Rand of Gauteng. The site is bordered to the west by the M43 (Sailfin), R554 and Van Dyk Dam to the north and open grasslands and Dalpark to the east and degraded open grasslands to the south (see Figure 1 above). Major bulk pipelines and railway track occur on the southern boundary of the site.

Invertebrate Assessment – Ptn 62 Witpoortjie 7

Figure 2. An elevation profile of the site. The site has a gentle sloping topography from the north towards the east with an average slope of 1.3%. The major topographical features are the artificially created mine dumps (old slimes dam) on the northern portion of the site.

Vegetation composition in the area consists of Mesic Highveld Grasslands in various stages of transformation and degradation falling within the Tsakane Clay Grassland (Gm 9) vegetation unit (Mucina & Rutherford 2006; see Figure 4 below). The majority of grasslands have been historically transformed through agricultural activities as well as high-density residential developments and associated high levels of anthropogenic disturbances including extensive illegal dumping activities, littering, frequent fires (burning of waste) and harvesting of traditional medicinal plants. The grasslands to the south of the site comprise of degraded grassland with limited herb and forb diversity. Patches of primary Themeda triandra grassland were observed on the western, southern as well as central portions of the site. Several patches of the hydrophilic Imperata cylindrica was observed within a mosaic in areas with elevated soil moisture throughout the site.

One general habitat sensitivity scans was carried out mainly during daylight hours (9h00- 14h00) on the 22nd of November 2018. The majority of the surveys were conducted on existing roads, livestock pathways as well as off-road vehicle and quad bike tracks within the grasslands. Due to the large size of the site little time was spent surveying the old slimes dam and mine dumps or degraded habitats

Invertebrate Assessment – Ptn 62 Witpoortjie 8

Figure 3. Vegetation map of the Witpoortjie site situated within Tsakane Clay Grassland (Gm9) (adapted from Mucina et al. 2006).

Invertebrate Assessment – Ptn 62 Witpoortjie 9 Vegetation type

Mesic Highveld Grassland is found mainly in the eastern, precipitation-rich regions of the Highveld, extending as far as the Northern Escarpment. These are predominantly ‘sour’ grasslands and are dominated primarily by andropogonoid grasses. The different grassland units are distinguished on the basis of geology and other substrate properties, as well as elevation, topography and rainfall.

The vegetation of the site falls within the Tsakane Clay Grassland (Gm 8) vegetation unit (Mucina & Rutherford 2006). The vegetation on the site comprised cool Highveld Grassland in various stages of transformation and degradation. Patches of Themeda traiandra were observed on the western, southern and eastern portions of the site. Three seasonally inundated depressions or pans were observed as well as a poorly defined valley bottom wetland on the western portion of the site. The northern portion is dominated by an old gold mine dump and slimes dam. The mine dump is poorly vegetated as large amounts of dust smothers the adjacent grasslands.

Synonyms: Cymbopogon-Themeda Veld (VT 48) (Acocks 1953) or Moist Cool Highveld Grassland (39) (Low & Rebelo 1995).

Locality & Physical Geography: and Gauteng Provinces: In patches extending in a narrow band from Soweto to Springs, broadening southwards to Nigel and towards Vereeniging, as well as north of the Vaal Dam and between Balfour and Standerton. Altitude is between 1 480-1 680 m.

Vegetation & Landscape Features: Flat to slightly undulating plains and low hills. Vegetation is short, dense grassland dominated by a mixture of common Highveld grasses such as Themeda triandra, Heteropogon contortus, Elionurus muticus and a number of Eragrostis species. Most prominent forbs are of the families Asteraceae, Rubiaceae, Lamiaceae and Fabaceae. Disturbances leads to an increase in the abundance of the grasses Hyparrhenia hirta and Eragrostis chloromelas (Mucina & Rutherford 2006).

Patches of natural Themeda triandra, Heteropogon contortus, Elionurus muticus grassland was observed on the western as well as central portions of the site. Several large clumps of Hypoxis hemerocallidea were observed on the southern portions of the site as well as adjacent to the seasonal pans. The grasslands on the site have low levels of anthropogenic disturbances due to the presence of security gaurds who mpatrol during the daylight hours. Activities noted included low-levels of harvesting of Hyparrhenia hirta and Ergagrostis chloromelas for thatch, removal of medicinal plants, frequent burning of grassland vegetation, scraping of vegetation and soils on the southern boundary, illegal dumping of building, litter and invasion of alien invasive vegetation (Eucalyptus camaldulensis, Verbena bonariensis, Campuloclinium macrocephalum).

Invertebrate Assessment – Ptn 62 Witpoortjie 10 Geology and Soils: The most significant rock is the basaltic lava of the Klipriviersberg Group (Ventersdorp Supergroup), together with the sedimentary rock of the Madzaringwe Formation of the Karoo Supergroup Group. Soils are typical of the Ba and Bb land types. Soils on the site were sandy to sandy-clay-loams. Large amounts of in-filled building waste has been dumped on the site. No natural rocky extrusions or outcrops on the site. The predominating soils along the adjacent Kliprivier (300m SW) are very clayey, black vertic or near vertic, mostly of montmorillonitic clays.

IMPORTANT TAXA

Graminoids (Grasses): Brachiaria serrata, Cynodon dactylon, Cynodon hirsutus, Digitaria ternate, Elionurus muticus, Eragrostis chloromelas, E. patentipilosa, E. plana, E. racemosa, Heteropogon contortus, Hyparrhenia hirta, Michrochloa caffra, Setaria sphacelata, Steraa nigrirostris, Themeda triandra, Trachypogon spicatus, Andropogon schirensis, Aristida adscensionis, A. bipartita, A. congesta, A. junciformis subsp. galpinii, Cymbopogon caesius, Digitaria diagonalis, Diheteropogon amplectens, Eragrostis micrantha, E. superba, Melinis nerviglumis, Harpochloa falx, Microchloa caffra, Paspalum dilatatum.

Herbs: Acanthospernum australe, Ajuga ophrydis, Eriosema salignum, Euryops transvaalensis, Gerbera viridifolia, Helichrysum nudifolium var. nudifolium, H. rugulosum, Hermania depressa, Lotononis macrosepala, Nidorella hottentotica, Pentasia prunelloides subs. latifolia, Pseudanum caffrum, Rotheca hirsuta, Selago paniculata, Senecio coronatus, S. inornatus, Vernonia oligocephala.

Geophytic Herbs: Aspidoglossum ovalifolium, Hypoxis rigidula var. pillosissima.

Semi-parasitic Herb: Striga asiatica.

Low Shrubs: Anthospermum hispidulum, A. rigidum subsp. pumilum, Chaetacanthus setiger, Tephrosia capensis var. acutifolia.

Semi-parasitic Shrub: Thesium impeditum.

Key Environmental Parameters: This vegetation type is restricted to clayey soils of the high rainfall areas of southern Gauteng and southern Mpumalanga highveld.

Economic Uses: The grasslands and soils are often ploughed as well as heavily utilised for grazing by cattle and sheep. The site is currently vacant and utilised for illegal dumping activities, pedestrian pathways, bush-toilets and limited grass harvesting.

Invertebrate Assessment – Ptn 62 Witpoortjie 11 Conservation Status: Tsakane Clay grasslands are considered to be Endangered. The conservation target is 24%. Only 1.5% statutorily conserved (Suikerbosrand, Olifantsvlei, Klipriviersberg, Marievale) or privately conserved (Avalon Nature Reserves, Ian P. Coester, Andros). More than 60% of the area already transformed by cultivation, urban sprawl, mining, dam building of road infrastructure. Large portions of Alberton, Springs, Tsakane and part of Soweto were constructed in the area of this vegetation unit.

Urbanisation is increasing and further expansions especially in the southern suburbs of Johannesburg and towns on the East Rand (especially Boksburg and Brakpan) will bring further pressure on the remaining vegetation. Land invasion within open Tsakane Clay grassland is also a potential for further destruction of this Endangered vegetation unit. Erosion is generally very low (93%).

Butterfly foodplants: Leerzia hexandra, the larval foodplant of meninx and likely to occur within the seasonally inundated pans. is no longer considered to be a species of conservation concern. Hermannia depressa, the larval foodplant of was observed. There are however no records of Aloeides dentatis in the vicinity of the site, nor was it observed during the survey. It appears that Hermannia depressa is considerably more widespread than Aloeides dentatis in Gauteng.

MATERIALS & METHODS

Invertebrates were sampled using active and passive methods. Active methods entail collection by an individual using various kinds of equipment, while passive methods involve specialised types of traps at specific sites in the field, which are visited at given time intervals.

Passive collection

Pitfall traps

Ten pitfall traps were placed ten meters apart, in a single transect. The pitfall traps were unbaited. The plastic buckets used for traps had a 1000 mL capacity and were 11 cm in diameter and 12 cm deep. All the traps were sunk into the ground so that the buckets’ rims were level with the soil surface. Buckets were filled to about one fifth their volumes with a solution of liquid soap and water to immobilise trapped invertebrates. Trap contents were collected 24 hours after the traps had been set. Only insects and arachnids were collected from the traps. Specimens were preserved in absolute ethanol and transported to the

Invertebrate Assessment – Ptn 62 Witpoortjie 12 laboratory for identification. Morphospecies were identified to order level and family level where possible.

Active collection

Sweepnetting

Sweepnetting was carried out during all site visits whilst transect netting was carried out on the 22nd November 2018. An insect net with a diameter of 40 cm was used for collecting insects and arachnids. Three transects were swept on the site and for the sake of standardisation, 20 sweeps of 180° constituted one transect (and thus one sample). Insects and arachnids from the samples were preserved in absolute ethanol and transported to the laboratory for identification. Morphospecies were identified to order level and family level where possible.

Beating

Due to the absence of indigenous trees on the site and the unlikelihood of catching any invertebrates of conservation concern by beating, this method was not employed.

Physical searches

Physical ground and rock searches were undertaken in order to identify threatened arachnids, scorpions and various insects which take refuge underground in burrows or under rocks. The site is not rocky in nature and lifting of the few rocks and building rubble present did not reveal any invertebrates of conservation interest.

Data recorded and red data species

A list of all identifiable insects and arachnids caught or seen on the site was compiled and is included in the results section.

A list of all the invertebrate species of conservation concern known to occur in the survey area is included in appendix A.

Invertebrate Assessment – Ptn 62 Witpoortjie 13 RESULTS

Invertebrate diversity recorded on Portion 62 of the Farm Witpoortjie 165-IR.

Class Insecta

Dragonflies and damselflies Order Suborder Zygoptera

Family Coenagrionidae

Ischnura senegalensis Suborder Anisoptera Family Gomphidae

Ceratogomphus pictus Family Aeshnidae

Anax imperator Family arteriosa

Trithemis furva There are no Odonatan species of conservation concern recorded for Gauteng.

Cockroaches Order Blattodea Family Blattidae

Deropeltis sp. There are no Cockroach species of conservation concern recorded for Gauteng.

Termites Order Isoptera Family Termitidae

Odontotermes badius Trinervitermes sp. There are no Termite species of conservation concern recorded for Gauteng.

Mantids Order Mantodea Family

Sphodromantis gastrica There are no Mantid species of conservation concern recorded for Gauteng.

Invertebrate Assessment – Ptn 62 Witpoortjie 14 Crickets, Grasshoppers and Locusts Order Orthoptera Family Anostostomatidae

Onosandrus sp.

Family Tettigoniidae

Conocephalus caudalis Family Gryllidae Gryllus bimaculatus Family Gryllotalpidae

Gryllotalpa africana

Family Tetrigidae Family Pyrgomorphidae

Phymateus viridipens Family Acrididae Acrotylus sp.

Tmetanota sp. There are no Orthopterans of conservation concern recorded for Gauteng.

Bugs Order Family Miridae

Deroeocoris sp. Family Lopodytes sp.

Reduvius sp. Family Coreidae Cletus sp. Family Pyrrhocoridae

Dysdercus intermedius Family Lygaeidae Spilostethus sp.

Nezara viridula Family Cicadellidae

Cofana spectra Family Aphididae There are no Hemipteran species of conservation concern recorded for Gauteng.

Thrips Order Thysanoptera There are no Thrip species of conservation concern recorded for Gauteng.

Invertebrate Assessment – Ptn 62 Witpoortjie 15 Lacewings and Antlions Order Neuroptera Family Chrysopidae

Chrysoperla sp. Family Myrmeleontidae

Cueta spp. Macronemurus tinctus There are no Neuropteran species of conservation concern recorded for Gauteng.

Beetles Order Coleoptera Family Carabidae

Craspedophorus sp. Family Scarabaeidae Subfamily Rutellinae Subfamily Dynastinae

Heteronychis arator Subfamily Scarabaeidae Copris sp. Family Lycidae

Lycus sp.

Family Melyridae

Astylus astromaculatus Family Coccinellidae Subfamily Coccinellinae

Micraspis sp. Subfamily Epilachninae Epilachna sp. Family Tenebrionidae Gonocephalum simplex Family Cerambycidae Family Chrysomelidae

Subfamily Chrysomelinae

Plagiodera sp. Subfamily Macrocoma sp.

Platycorynus sp. Family Curculionidae No of conservation concern were observed on the site.

Invertebrate Assessment – Ptn 62 Witpoortjie 16 Flies Order Diptera Family Tipulidae

Family Psychodidae

Family Bibionidae Family Asilidae

Leptogaster sp. Family Bombylidae Family Muscidae Musca domestica

Lispe sp. Family Calliphoridae

Chrysomya sp. There are no Dipteran species of conservation concern recorded for Gauteng.

Caddisflies Order Trichoptera There are no Caddisfly species of conservation concern recorded for Gauteng.

Moths and Butterflies Order Family Crambidae

Subfamily Crambinae

Subfamily Phycitinae

Family Pterophoridae

Family Alucitidae

Family Geometridae

Family Noctuidae Family Nymphalidae Subfamily Danainae

Danaus chrysippus Subfamily Heliconiinae

Acraea spp. Subfamily Nymphalinae

Junonia hierta cebrene

Junonia oenone oenone

Vanessa cardui Family Subfamily Lycaenidae

Aloeides aranda

Family

Invertebrate Assessment – Ptn 62 Witpoortjie 17 Subfamily Pierinae

Colotis euippe

Belenois aurota

Pontia helice

Mylothris agathina Subfamily Coliadinae

Catopsilia florella

Eurema brigitta Family Papilionidae Subfamily Papilioninae

Papilio demodocus No butterflies of conservation concern were observed on the site.

Sawflies, Wasps, Bees & Order Suborder Apocrita Family Braconidae

Family Chrysididae

Family Mutilidae Family Vespidae

Polistes sp. Family Apidae Apis mellifera Family Formicidae

Messor capensis

Solenopsis punctaticeps Linepithema humile There are no Wasp, Bee or species of conservation concern recorded for Gauteng.

Spiders and scorpions

Class Arachnida

Scorpions Order Scorpiones Family Buthidae Uroplectes triangulifer No scorpions of conservation concern were observed on the site.

Spiders Order Aranaea

Invertebrate Assessment – Ptn 62 Witpoortjie 18 Family Araneidae

Subfamily Araneinae

Larinia sp. Family Tetragnathidae

Subfamily Leucauginae

Leucauge sp. Family Uloboridae

Subfamily Uloborinae Family Eresidae

Subfamily Eresinae Family Agelenidae Olorunia sp.

Family Pholicidae

Pholcus sp. Family Deinopidae Family Lycosidae

Family Selenopidae Selenops sp. Family Zodariidae

Family Thomsidae

Rucinia sp. No spiders of conservation concern were observed on the site.

Invertebrate Assessment – Ptn 62 Witpoortjie 19 DISCUSSION

It is usually not feasible to sample invertebrate diversity adequately over a relatively short period of time. There are several selective factors that control certain associations in invertebrate communities. These factors include the nature of the soil substrate, fauna and flora of the specific region, rainfall and temperature. The widespread use of pesticides in an area, as well as the level of pollution, might lead to a decrease in the population sizes of invertebrates. Maximum insect activity is usually correlated with the onset of the rainy season.

Conditions for maximum insect activity were optimal during initial site visits. Maximum temperatures were constantly above 25°C for some period of time and much rain had yet been recorded for the locality (10 – 12 mm of rain is usually regarded as sufficient to stimulate peak insect activity). Different species emerge at different times of a season, often depending on the weather. Thus, the availability of invertebrates for trapping will depend on the weather and on their abundance.

Furthermore, the temporal development of the various species that constitute communities may make individuals available for capture for only a short time. Most sampling devices or techniques target only a single stage of the life cycle. The adult stages of most invertebrates are usually more conspicuous and easier to collect than when individuals are present in egg, juvenile (nymphal or larval), pupal or sub-adult stages. However, some adult insects live for a very short time and when emergence of a population is synchronised; adults may only be present in the field for a week or less. Due to time constraints, certain sampling methods were not employed. One such method is light trapping, thus excluding various nocturnal species that were not collected from the pitfall traps.

It is preferable to identify specimens to the species level, because for nearly all objectives it is better to have specific information on carefully chosen groups than family-level information on many. However, securing reliable identification to the species-level is the greatest single difficulty in invertebrate biodiversity. Except in some of the best known groups, expert knowledge is required to ensure that identifications are accurate. Such expertise is often both extremely limited and in great demand for a great many activities.

During site visits, no invertebrates of conservation concern were located. It must however be mentioned that whilst employing the Rapid Biodiversity Assessment (RBA) method, there does exist the possibility that certain other rare invertebrate species may not have been encountered.

Invertebrate Assessment – Ptn 62 Witpoortjie 20 Four invertebrate species of conservation concern are known to occur in the vicinity of the survey area. These include three species of butterfly and one species of cetonid beetle. None of these species were encountered during the survey. This, however, does not imply that one is unlikely to encounter any of these species in the study area as they may have been missed by sampling due to multiple factors.

Lepidochrysops praeterita, commonly known as the Highveld Blue, is rare and localized on highveld grassland between Potchefstroon in North West Province, Sasolburg in the Province and Walkerville in Gauteng Province. This butterfly frequents hillsides on which Becium grandiflorum grows, flying fast and close to the ground from September to November. A small population has been detected in the Walkerville area which is located more than 50km to the east of the survey area. No specimens were observed during the survey. Due to the absence of suitable habitat (highveld grassland with trees) as well as its larval food plant, the species can be considered absent from the survey area.

Chrysoritis aureus, commonly known as the Heidelberg Copper Butterfly, is a monophagous, myrmycophilous butterfly species, known from a handful of localities on the Heidelberg- Balfour-Greylingstad ridge system. It is not immediately apparent what the habitat of this species is, ie what factors determine suitable habitat. The known records represent colonies of this butterfly which occur around rock faces inhabited by the host ant species and where the host plant also occurs. Colonies are made up several tens of individuals which are active over an area of about 100m2 in the vicinity of the ant colonies. The butterflies do not occur in areas where the host plant grows larger than about 1m in height. It has been speculated that the species only occurs at the highest altitudes on the ridge system, but there are some colonies found lower than the proposed suitable altitudinal range. It has also been speculated that it only occurs in ‘rain shadow’ areas on the ridge, usually on SE facing slopes, where the resultant water stress inhibits the production of allelochemicals in the host plant, but this has not been tested. Fire has been demonstrated to be important for the species in that it keeps the vegetation structure open (Terblanche et al 2003). Specimens of this species were not observed during the survey, nor does suitable habitat occur on the site.

Aloeides dentatis dentatis (Figure 3.2) is a butterfly species known to be threatened by urban development in Gauteng. This species is known from three colonies in Gauteng, namely the Witpoortjie colony, the Glenvista colony and the Suikerbosrand colony. The latter colony is protected in the Suikerbosrand Nature Reserve and its larval foodplant is Lotononis eriathrina. This plant was not found to be present on the site. The Witpoortjie colony is protected in the Ruimsig Entomological Reserve and its larval foodplant is either Hermannia depressa or Hermannia jacobeifolia. A concerted effort was made to locate either the species itself, any of its three larval foodplants or its associated ant species capensis. Despite extensive searching, none of the three larval foodplants were observed on the site. It can therefore be confidently stated that Aloeides dentatis is absent from the site.

Invertebrate Assessment – Ptn 62 Witpoortjie 21 Ichnestoma stobbiai (Figure 3.3) is a cetonid beetle of immense scientific interest and conservation concern. Females are flightless and adults emerge for only 2 - 4 days, thereby severely restricting this species in terms of gene flow and dispersal ability. I. stobbiai was previously thought to be extremely habitat specific and reside almost exclusively under tufts of the grass species Eragrostis micrantha. The location of new populations of this species in caravan parks and exotic gardens suggest that the species is more robust than previously thought. Apart from one population near Hartbeespoort dam, this species is found only in Gauteng and is severely threatened due its poor dispersal ability. There are currently eleven confirmed populations of this beetle in Gauteng, none of which occur in close vicinity of the survey area.

Invertebrate Assessment – Ptn 62 Witpoortjie 22 RECOMMENDATIONS

The proposed development is not expected to impact significantly on any sensitive floristic or faunal habitat, Red Data species, populations, assemblages or communities, since the ecological status of the area is degraded.

General mitigation measures

Development should only take place in areas with an ecological footprint. Although the site is ecologically degraded, the new landowner needs to remove all the alien invasive plant species and employ further restrictions and control, as specified by CARA Regulations. An ecological management plan must be compiled by a suitably qualified specialist for implementation by the appropriate management authority. This ecological management must include a fire management programme and an ongoing monitoring and eradication programme for all non-indigenous species, with specific emphasis on invasive and weedy species. Where removal of alien species may leave soil exposed, alternative indigenous species should be established to prevent any erosion. Plants growing naturally on the site must, as best possible be retained and incorporated into landscaping. When additional plant species are used for landscaping, special emphasis should be focused on forage and host plants required by herbivores and pollinators present in the area and must otherwise only be limited to those indigenous to South Africa, although species that are locally indigenous or endemic should enjoy preference (Refer to table 1). The integrity of natural vegetation that falls outside landscaped areas, such as indigenous grass species and leaf litter, should be preserved, as it provides a habitat, microclimate and food source to various smaller vertebrates and notably invertebrates. Moreover it also provides a habitat to many reptiles and invertebrates, some of which may be endangered and/or protected species. Several of these species may complete their entire life cycles in this specific niche.

Table 1. List of plants and shrubs are recommended for butterflies (nectar plants) Pentas lanceolata and Pentas lanceolata Buddleja salvifolia Verbena spp. Asclepias spp. Bougainvillea spp. (Varieties such as Killie Campbell) Plumbago auriculata Impatiens spp. Kalanchoe spp. Lobelia species Limonium spp. Asystasia gangetica

Invertebrate Assessment – Ptn 62 Witpoortjie 23 Building activities must be restricted and carefully monitored to keep disturbance to a minimum, and must be appropriately rehabilitated and managed. This entails the removal and proper disposal of all rubble and litter previously dumped on the site illegally, as well as all scrap materials, building rubble and rubbish dumped on the site during construction, at official municipal dumping grounds. No dumping of any materials in undeveloped open areas or along the seasonal stream should be allowed and this must be actively managed. Construction must preferably take place during the dry season and no temporary housing, temporary ablution, disturbance of natural habitat, storing of equipment or any other use of the buffer/flood zone whatsoever, may be permitted during the construction phase. All construction-related impacts (including service roads) must be contained within the fenced-off development areas” (Phab, 2006).

It is imperative that adequate erosion preventative mechanisms are implemented throughout the construction phase. Erosion resulting from the development should be appropriately rehabilitated preventing further habitat deterioration. Stormwater runoff must be correctly managed during all phases of the development. Special care needs to be taken during the construction phase to prevent surface stormwater containing sediments and other pollutants from entering the drainage line. A surface runoff and stormwater management plan must be put in place. The total sealing of walkways, pavements, drive ways and parking lots should not be permitted in the free space system. These should form part of and be contained within the areas earmarked for development. This would aid in the minimising of artificially generated surface stormwater runoff.

The use of insecticides, herbicides and other chemicals should not be permitted within 200m of the open space system. An integrated pest management programme, where the use of chemicals is considered as a last option, should be employed. However, if chemicals are used to clear invasive vegetation and weedy species or for the control of invertebrate pests, species-specific chemicals should be applied and in the recommended dosages. General spraying should be prohibited and the application of chemicals as part of a control programme should not be permitted to take place on windy days.

Outside lighting should be designed to minimize impacts, both directly on especially rare or endangered invertebrate species and indirectly by impacts on populations of prey species. All outside lighting should be directed away from sensitive areas. No domestic cats should be allowed, and where domestic dogs are kept, the entire development should be fenced to prevent dogs from straying into the free space system. Dogs should not be allowed to wonder into any of the natural surroundings, even if accompanied by the owner, as this poses a serious threat to the persistence of wild species, particularly small mammals.

Invertebrate Assessment – Ptn 62 Witpoortjie 24 REFERENCES

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Invertebrate Assessment – Ptn 62 Witpoortjie 26 Appendix A

Invertebrates of conservation concern known to occur in the vicinity of the survey area

Class Insecta

Beetles

Order Coleoptera Family Scarabaeidae Subfamily Cetoniinae Ichnestoma stobbiai

Butterflies

Order Lepidoptera Family Lycaenidae Subfamily Theclinae Tribe Aphnaeini Aloeides dentatis dentatis Chrysoritis areus Subfamily Polyommatinae Tribe Polyommatini Lepidochrysops praeterita

Invertebrate Assessment – Ptn 62 Witpoortjie 27