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Location South Africa, Western Cape
Central coordinates 19o 54.00' East  34o 25.00' South
IBA criteria A1, A2, A3, A4i
Area 300,000 ha
Altitude 0 - 400m
Year of IBA assessment 2001

BirdLife South Africa



Summary Located at the southern tip of the African continent, this large agricultural district stretches from Caledon to Riversdale and encompasses the area south of these two towns, running between the coastal towns of Hermanus and Stilbaai and extending approximately 300 000 hectares. The Overberg holds the large Blue Crane Anthropoides paradiseus populations.

Site description Located at the southern tip of the African continent, this large agricultural district stretches from Caledon to Riversdale and encompasses the area south of these two towns, running between the coastal towns of Hermanus and Stilbaai. De Hoop Nature Reserve, which abuts this area, is considered a separate IBA (IBA ZA098). The topography consists of low-lying rolling coastal plains. The landscape consists primarily of cereal croplands and cultivated wheat pastures and crop fields, although a fair amount of natural vegetation still remains along the coast, especially on the Soetanysberg and Agulhas Plain, which hold at least 1,700 plant species. The coast holds thicket, which is dominated by forest patches of milkwood Sideroxylon. Localized, fragmented patches of renosterveld are found throughout the area.

Key Biodiversity See Box and Tables 2 and 3 for key species. The Overberg holds the largest population of Grus paradisea in the world. Numbers increase during the winter months when many pairs, which have completed breeding activities, join large loose flocks that congregate in this area. At times this IBA can hold nearly 20% of this species’s global population, as well as holding large numbers of Neotis denhami. Gyps coprotheres, which breed at Potberg in the De Hoop Nature Reserve (IBA ZA098), occasionally forage over the agricultural matrix, where Circus maurus is also found frequently. The site also covers a large proportion of the global range of the recently described Certhilauda brevirostris. Within this area, it is almost confined to stony wheatfields and pastureland. Despite its limited range, the species appears to be secure, provided that current land-use patterns persist. Some typically karroid birds are also found within the wheat matrix and the occasional renosterveld patches, including Eupodotis vigorsii, Parus afer and Cercomela sinuata.

Non-bird biodiversity: The area is extremely rich in highly threatened endemic flora, including the spectacular Leucadendron elimense, L. modestum and L. laxum. The discovery of a new species of Proteaceae, Serruria nova, in 1998, suggests that complete surveys of the area will yield many new endemic species. Among frogs, the spectacular Hyperolius horstockii occurs and Heleophryne purcelli may occur in montane rivers in the wheatbelt matrix.

Populations of IBA trigger species

Species Season Period Population estimate Quality of estimate IBA Criteria IUCN Category
Cape Francolin Pternistis capensis resident  1998  present  A3  Least Concern 
Black Harrier Circus maurus resident  present  A1  Vulnerable 
Blue Crane Anthropoides paradiseus winter  2,914-3,484 individuals  A1, A4i  Vulnerable 
Certhilauda brevirostris resident  1998  present  A3  Not Recognised 
Cape Bulbul Pycnonotus capensis resident  1998  present  A3  Least Concern 
Orange-breasted Sunbird Nectarinia violacea resident  1998  present  A2, A3  Least Concern 
Cape Sugarbird Promerops cafer resident  1998  present  A2, A3  Least Concern 
Cape Siskin Serinus totta resident  1998  present  A2, A3  Least Concern 

IBA Monitoring

2013 very high not assessed low
unset
Medium - based upon reliable but incomplete / partially representative data

Agriculture and aquaculture annual & perennial non-timber crops - agro-industry farming happening now whole area/population (>90%) moderate to rapid deterioration very high
Agriculture and aquaculture annual & perennial non-timber crops - shifting agriculture happening now some of area/population (10-49%) slow but significant deterioration medium
Agriculture and aquaculture livestock farming and ranching (includes forest grazing) - agro-industry grazing, ranching or farmin happening now majority/most of area/population (50-90%) slow but significant deterioration high
Agriculture and aquaculture livestock farming and ranching (includes forest grazing) - small-holder grazing, ranching or farming happening now some of area/population (10-49%) slow but significant deterioration medium
Biological resource use hunting & collecting terrestrial animals - persecution/control happening now some of area/population (10-49%) slow but significant deterioration medium
Climate change and severe weather drought likely in long term (beyond 4 years) whole area/population (>90%) slow but significant deterioration medium
Climate change and severe weather habitat shifting and alteration likely in long term (beyond 4 years) some of area/population (10-49%) slow but significant deterioration medium
Climate change and severe weather temperature extremes likely in long term (beyond 4 years) whole area/population (>90%) slow but significant deterioration medium
Energy production and mining renewable energy likely in short term (within 4 years) some of area/population (10-49%) slow but significant deterioration medium
Human intrusions and disturbance recreational activities happening now some of area/population (10-49%) no or imperceptible deterioration low
Invasive & other problematic species, genes & diseases invasive non-native/alien species/diseases - named species happening now some of area/population (10-49%) slow but significant deterioration medium
Invasive & other problematic species, genes & diseases problematic native species/diseases - named species happening now some of area/population (10-49%) slow but significant deterioration medium
Natural system modifications dams & water management/use - abstraction of surface water (agricultural use) happening now some of area/population (10-49%) slow but significant deterioration medium
Natural system modifications fire & fire suppression - increase in fire frequency/intensity happening now some of area/population (10-49%) slow but significant deterioration medium
Natural system modifications other ecosystem modifications happening now some of area/population (10-49%) slow but significant deterioration medium
Pollution agricultural & forestry effluents - herbicides and pesticides happening now majority/most of area/population (50-90%) slow but significant deterioration high
Pollution agricultural & forestry effluents - nutrient loads happening now some of area/population (10-49%) slow but significant deterioration medium
Pollution domestic & urban waste water - type unknown/unrecorded happening now small area/few individuals (<10%) slow but significant deterioration low
Pollution excess energy - noise pollution likely in short term (within 4 years) some of area/population (10-49%) slow but significant deterioration medium
Pollution industrial & military effluents - type unknown/unrecorded happening now small area/few individuals (<10%) slow but significant deterioration low
Residential and commercial development commercial and industrial development happening now some of area/population (10-49%) slow but significant deterioration medium
Residential and commercial development housing and urban areas happening now some of area/population (10-49%) slow but significant deterioration medium
Residential and commercial development tourism and recreation areas happening now some of area/population (10-49%) no or imperceptible deterioration low
Transportation and service corridors roads and railroads happening now small area/few individuals (<10%) slow but significant deterioration low
Transportation and service corridors utility & service lines likely in short term (within 4 years) some of area/population (10-49%) slow but significant deterioration medium

Artificial - terrestrial Arable land  0 0 moderate (70-90%) moderate (70-90%) unfavourable
Shrubland Shrubland - Cape (fynbos)  0 0 very poor (< 40%) poor (40-69%) very unfavourable

Gyps coprotheres Cape Vulture 210 210 individuals 100 favourable
Circus maurus Black Harrier 100 100 individuals 100 favourable
Neotis denhami Denham's Bustard 195 195 individuals 100 favourable
Anthropoides paradiseus Blue Crane 6000 6000 individuals 100 favourable

Little/none of site covered (<10%)  No management plan exists but the management planning process has begun  Some limited conservation initiatives are in place  low 

Protected areas

Protected area Designation Area (ha) Relationship with IBA Overlap with IBA (ha)  
Cape Floral Region Protected Areas World Heritage Site 553,000 protected area is adjacent to site 0  

Habitats

IUCN habitat Habitat detail Extent (% of site)
Grassland   -
Shrubland Shrubland - Cape (fynbos)  -
Artificial - terrestrial Arable land  major

Land use

Land-use Extent (% of site)
agriculture -
nature conservation and research 20%
tourism/recreation -

References Allan (1989, 1992, 1993a, 1994a,c, 1995a,b, 1996b), Allan and Young (1998), Anderson (1990), Cowling et al. (1988), Hitchcock (1996), Scott (1992), Siegfried (1985), Tarboton (1992), van Ee (1981).

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Recommended citation  BirdLife International (2015) Important Bird Areas factsheet: Overberg Wheatbelt. Downloaded from http://www.birdlife.org on 29/05/2015

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