4.3 RESULTS
4.3.1 Site similarity
Overall, family similarity between forest pairs was greater than species similarity, as reflected in the larger coefficients obtained. Results for the family level were similar to the species figures, but several differences are evident. All Drakensberg forest pairs shared 55% or more of their families, except for the New Agatha:Forest Glens and Swartbos:Forest Glens pairs. Only half of the Soutpansberg mistbelt forest pairs shared 55% or more of their families. Grootbosch shared 55% or more of its families with all other forests except Ratombo. The invertebrate family composition of Baccarat was also similar to many other forests, sharing 55% or more of its families with all other mistbelt forests. Although the semi-deciduous forests Roodewal and Ratombo were not similar on the species level to each other or any mistbelt forest, high degrees of family similarity were present between the Roodewal:Forest Glens, Ratombo:Grootbosch and Ratombo:Swartbos pairs.
Despite the similarities in the family composition of some forest pairs, two of the three forest subtypes had families that were not found in any other forest subtype. After dividing the mistbelt forest subtype by region, it was shown that the Drakensberg mistbelt forests had the most unique families, followed by the Soutpansberg mistbelt forests and the semi- deciduous scrub forest (Roodewal). Only the semi-deciduous mixed forest (Ratombo) did not have any unique families (Figure 4.1b). Each individual mistbelt forest also had unique species and six of the nine mistbelt forests even had families unique to that forest patch (Figure 4.2).
Jaccard similarity coefficients were calculated for species and families shared between forest regions and individual forests. The target invertebrate composition of the whole Soutpansberg region was compared to each individual Drakensberg forest and the target invertebrate composition of the whole Drakensberg region was compared to each individual Soutpansberg forest. The values obtained are presented in Figure 4.3.
On the species level, Grootbosch was most similar to the Soutpansberg forests, while Forest Glens was the least similar. These forests are the closest and furthest from the Soutpansberg respectively. However, family composition did not mirror these trends and Baccarat was most similar to the Soutpansberg on the family level while Swartbos, Baccarat’s nearest neighbour, was the least similar (Figure 4.3a). Hanglip’s species and family composition were most similar to the Drakensberg forests, even though it is
relatively distant from the region. On the species level, Roodewal was the least similar to the Drakensberg and Ratombo was the least similar on the family level (Figure 4.3b).
Table 4.1: Similarities in invertebrate family and species composition between Limpopo Province forests. Jaccard similarity coefficients are given for forests sharing a) 30% or more of their invertebrate species and b) 55% or more of their invertebrate families. All values have been multiplied by 100 for ease of interpretation. Forest names are abbreviated as follows: Hanglip = HAN, Roodewal = ROD, Goedehoop = GHP, Ratombo
= RAT, Entabeni = ENT, Thathe Vondo = TV, Grootbosch = GRO, New Agatha = NAG, Swartbos = SWB, Baccarat = BAC, Forest Glens = FGL.
Site HAN ROD GHP RAT ENT TV GRO NAG SWB BAC FGL
a) HAN -
ROD -
GHP -
RAT -
ENT 43 37 -
TV 50 31 44 -
GRO 30 30 39 33 -
NAG 37 -
SWB 30 43 37 -
BAC 30 42 37 40 -
FGL 38 30 42 39 33 39 -
Site HAN ROD GHP RAT ENT TV GRO NAG SWB BAC FGL
b) HAN -
ROD -
GHP -
RAT -
ENT 58 -
TV 61 59 -
GRO 59 59 63 57 65 -
NAG 57 -
SWB 61 68 67 -
BAC 58 64 56 59 74 61 61 -
FGL 64 63 57 57 57 -
Figure 4.1: The contribution of the three Limpopo Province forest subtypes to invertebrate richness where a) is the species composition and b) is the family composition. The mistbelt forest subtype has been divided according to region.
0 20 10 40 30 60 50 80 70 90
0 20 10 40 30 60 50 80 70 90
Number of invertebrate speciesNumber of invertebrate families
Soutpansberg Mistbelt Forests
Drakensberg Mistbelt Forests
Semi-deciduous Scrub Forest Semi-deciduous
Mixed Forest
Shared with all forest subtypes
Shared with 2 other forest subtypes
Shared with 1 other forest subtype
Shared with no other forest subtype (i.e. unique)
Shared with all forest subtypes
Shared with 2 other forest subtypes
Shared with 1 other forest subtype
Shared with no other forest subtype (i.e. unique)
Forest subtype
a)
b)
0 20 10 40 30 60 50 80 70 90
0 20 10 40 30 60 50 80 70 90
Number of invertebrate speciesNumber of invertebrate families
Soutpansberg Mistbelt Forests
Drakensberg Mistbelt Forests
Semi-deciduous Scrub Forest Semi-deciduous
Mixed Forest
Shared with all forest subtypes
Shared with 2 other forest subtypes
Shared with 1 other forest subtype
Shared with no other forest subtype (i.e. unique)
Shared with all forest subtypes
Shared with 2 other forest subtypes
Shared with 1 other forest subtype
Shared with no other forest subtype (i.e. unique)
Forest subtype
a)
b)
Figure 4.2: The contribution of each forest sampled in Limpopo Province to invertebrate diversity where a) is the species composition and b) is the family composition. Forest names are abbreviated as follows: Hanglip = HAN, Roodewal = ROD, Goedehoop = GHP, Ratombo = RAT, Entabeni = ENT, Thathe Vondo = TV, Grootbosch = GRO, New Agatha
= NAG, Swartbos = SWB, Baccarat = BAC, Forest Glens = FGL. Forest names are coded by vegetation subtype (M = mistbelt forest, SS = semi-deciduous scrub forest, SM = semi- deciduous mixed forest).
Shared with all other forests Shared with forests in the same and other region Shared only with forests in the other region
Shared only with other forests in the same region
Shared with no other forest (i.e. unique)
Shared with all other forests Shared with forests in the same and other region Shared only with forests in the other region
Shared only with other forests in the same region
Shared with no other forest (i.e. unique)
0 10 20 30 40 50
0 10 20 30 40 50
Number of invertebrate speciesNumber of invertebrate families
a)
b)
HAN ROD GHP RAT ENT TV GRO NAG SWB BAC FGL
M SS M SM M M M M M M M
Shared with all other forests Shared with forests in the same and other region Shared only with forests in the other region
Shared only with other forests in the same region
Shared with no other forest (i.e. unique)
Shared with all other forests Shared with forests in the same and other region Shared only with forests in the other region
Shared only with other forests in the same region
Shared with no other forest (i.e. unique)
Shared with all other forests Shared with forests in the same and other region Shared only with forests in the other region
Shared only with other forests in the same region
Shared with no other forest (i.e. unique)
Shared with all other forests Shared with forests in the same and other region Shared only with forests in the other region
Shared only with other forests in the same region
Shared with no other forest (i.e. unique)
0 10 20 30 40 50
0 10 20 30 40 50
Number of invertebrate speciesNumber of invertebrate families
a)
b)
HAN ROD GHP RAT ENT TV GRO NAG SWB BAC FGL
M SS M SM M M M M M M M
Figure 4.3: Comparison of the invertebrate composition of forest regions with individual forests. Jaccard similarity coefficients for the number of species and (families) shared between a) all Soutpansberg forests and each forest sampled in the Drakensberg and b) all Drakensberg forests and each forest sampled in the Soutpansberg. All values have been multiplied by 100 for ease of interpretation. Dotted lines indicate where map areas have been removed. See Figure 2.1 (pg. 36) for actual distances between regions.
Hanglip 28(55) Roodewal 14(51)
Goedehoop 26(51) Ratombo 18(41) Thathe Vondo 26(48)
Entabeni 26(50)
All Drakensberg Forests Forest Glens 16(49) New Agatha 20(43)
Baccarat 22(56) Swartbos 19(41)
Grootbosch 25(49) All Soutpansberg Forests
a)
b)
Hanglip 28(55) Roodewal 14(51)
Goedehoop 26(51) Ratombo 18(41) Thathe Vondo 26(48)
Entabeni 26(50)
All Drakensberg Forests Forest Glens 16(49) New Agatha 20(43)
Baccarat 22(56) Swartbos 19(41)
Grootbosch 25(49) All Soutpansberg Forests
a)
b)
Forest Glens 16(49) New Agatha 20(43) Baccarat 22(56)
Swartbos 19(41)
Grootbosch 25(49) All Soutpansberg Forests
a)
b)
New Agatha 20(43) Baccarat 22(56)
Swartbos 19(41)
Grootbosch 25(49) All Soutpansberg Forests
a)
New Agatha 20(43) Baccarat 22(56)
Swartbos 19(41)
Grootbosch 25(49) All Soutpansberg Forests
a)
b)