The southern Langeberg is defined as the Langeberg Range between Kogmanskloof and the Gourits river. The Langeberg is one of several east–west trending mountain ranges in the Western Cape. The mountain range runs c.170 km from 35 km west of Swellendam in the west, to c.30 km north-east of Riversdale in the east. South of the range the Agulhas Plain and Overberg wheatbelt (IBA ZA094) stretch towards the coast. To the north lie the open plains of the Little Karoo. The area can be divided into three distinct sectors: Marloth Nature Reserve; Boosmansbos Wilderness Area; and the Bergfontein–Rooiwaterspruit–Phesantefontein area which holds Garcia State Forest. The mesic mountain fynbos is dominated by a multitude of plant communities. Afromontane forest patches, found in deep secluded mesic gorges, are dominated by trees such as Cunonia, Halleria, Pterocelastrus, Rapanea and Podocarpus. On the northern slopes and plains of the Little Karoo, karroid scrub appears. The Little Karoo is rocky and hilly, and concentrates run-off into pockets, resulting in a varied flora. On some hills and ridges, renosterbos is frequently present.
See Box and Tables 2 and 3 for key species. In the fynbos, Nectarinia violacea is widespread in ericas, while Promerops cafer and Serinus leucopterus are almost restricted to the proteoid elements. Francolinus capensis, Pycnonotus capensis and Serinus totta are widespread, while Bradypterus victorini is localized, restricted to moist seeps in hilly areas, where it is common. Chaetops frenatus and Geocolaptes olivaceus are common on most rocky slopes above 1,000 m. Within the low fynbos scrub both Turnix hottentotta and Sarothrura affinis are found. The isolated forest patches in the range hold several forest endemics, including Campethera notata, Bradypterus sylvaticus and Serinus scotops. Other forest species, some of which are at the western limit of their distribution, include Telophorus olivaceus, Apaloderma narina and Stephanoaetus coronatus.The Little Karoo plains and foothills of the north-facing Langeberg hold Eupodotis vigorsii, Certhilauda albescens, Cercomela sinuata, Cercomela schlegelii and Malcorus pectoralis. Serinus alario occurs whenever there is seeding grass and water. Belts of riverine Acacia woodland and hill scrub provide food, shelter and breeding habitat for many species, including Sylvia layardi and Parus afer. Anthus crenatus, Onychognathus nabouroup and the secretive and localized Euryptila subcinnamomea occur in rocky gorges and kloofs. Other arid-zone species occurring in the Little Karoo portion of the IBA include Melierax canorus, Batis pririt, Stenostira scita and Serinus albogularis.The agricultural wheat-growing belt to the south, which nestles up against the Langeberg slopes, holds populations of Grus paradisea, Neotis denhami, Circus maurus, Sagittarius serpentarius and Ciconia ciconia, all of which forage regularly within the modified agricultural matrix of the Langeberg.
Non-bird biodiversity: Of the 1,228 plant species recorded in the southern Langeberg, 160 (13%) are restricted to the range. The monotypic family Geissolomataceae is endemic to the range as is the monotypic genus Langebergia (Compositae). There are 48 endemic ericas and 17 endemic restios in the southern Langeberg. This area is also home to several special vertebrate species; Breviceps acutirostris is virtually endemic to the Langeberg. Barbus tenuis (EN) is globally restricted to the tributaries of the Keurbooms and Gourits rivers; the latter forms the eastern border of this IBA and it may hold a small population of this threatened and highly localized fish species. The spectacular Heleophryne purcelli is restricted to perennial streams in forested, boulder-strewn gorges in montane areas; it is endemic to the Western Cape. Other localized amphibians found in the Langeberg include Breviceps fuscus and Strongylopus bonaspei, which are restricted to the Cape Floral Kingdom. Capensibufo tradouwi breeds in moist depressions, vleis and springs, and it is found in the Langeberg and the Cedarberg–Koue Bokkeveld complex (IBA ZA080).
Pressure/threats to key biodiversity
In 1928 Marloth Nature Reserve, 129 ha in size, was set aside behind Swellendam for the local residents. In 1981, in accordance with the policy of the former Directorate of Forestry and Environmental Conservation (now under control of the Department of Water Affairs and Forestry) to extend reserves for more effective management, the reserve was enlarged to more than 11,000 ha. Farther east, the Boosmansbos Wilderness Area (14,200 ha), proclaimed in 1978, forms part of the Grootvadersbosch State Forest. Similarly, Garcia State Forest (12,000 ha) is managed principally to protect the water-catchment area.Invasive non-native trees of Acacia, Hakea and Pinus pose a serious threat to both vegetation and water conservation in these mountains. Locally, these exotic taxa can dominate thousands of hectares, significantly modifying soil composition, fire regime and natural plant and animal communities, threatening many indigenous species with extinction. Alien trees are also known to accelerate riverbank erosion and reduce in-stream flow through excessive transpiration. The control of invasive alien taxa is the single largest task facing most managers in this biome. Biocontrol agents, including fungus and insects, have been introduced to prevent the spread of alien species, and some have been extremely successful. The ‘Working for Water’ programme, initiated by DWAF, involves physical removal of alien plants in water-catchment areas. This ingenious programme increases water run-off and simultaneously employs people.Threats to the karroid plains of the Little Karoo to the north include overgrazing of the surrounding farmland, resulting in degradation of habitat, potentially reducing populations of sensitive wide-ranging species. Several pesticides and poisons are used in the farming areas. The effects that they are having on bustards, cranes, raptors and other tertiary consumers in the region are currently unknown.
BirdLife International (2022) Important Bird Areas factsheet: Langeberg Mountains. Downloaded from
http://www.birdlife.org on 26/06/2022.