South African National Parks (SANParks) is implementing rehabilitation projects in parks where acquired lands have degrees of degradation. Such parks need to have empirical data to determine the degree of degradation and the success of the projects. We sampled epigeal ants at degraded and control sites in Mountain Zebra and Mokala National Parks to acquire the empirical data. With the data, our main aims were to: 1) determine the impact of degradation on the ant community; 2) determine if the rehabilitation period influences the difference between the degraded and control sites; and, 3) identify the degradation that affected the ant community the most. The majority of the degraded sites had lower abundance, species richness, Shannon-Wiener Diversity, common- and exclusive-species than their respective control sites. All the degraded sites had a lower abundance of ants compared to their respective controls. The majority of the degraded sites had lower species richness, higher Shannon-Weiner Diversity Index and higher ant species dominance than their respective controls. The rehabilitation periods differently influenced the difference between the degraded and control sites. Degraded sites that had undergone longer rehabilitation times had lower dissimilarity to their respective controls, while a degraded site with shorter rehabilitation period was very different to its control. Ploughing appears to have longer lasting degradation-impact on ant communities than herbicides applications. A site with ploughing degradation was very dissimilar to its control while sites with chemical degradation had lower disparities to their respective controls. Different degradation activities, therefor, affect ant recovery differently.
Attention should be paid to the type of degradations that are at the lands identified for expanding the conservation areas. Some of these degradations seem persistent and slow to rehabilitate. Variety of organisms (such as ants in this case) should be included when determining the degradation status of a conservation land.
Habitat loss is the decline of ecological (or environmental) area (or community) by any action resulting in unfavourable conditions for species to complete their lifecycles (Galvin
A reconnaissance was carried out in two SANParks, Mountain Zebra (MZNP) and Mokala (MoNP), to compare ant diversity and abundance in degraded and undisturbed control areas. Over-grazing, ploughing and eradication of alien species lead to degradation in MZNP, whilst chemical treatment to control woody plant species was the main factor in MoNP.
We chose to use ants as they often respond temporally and spatially to degradation (Gollan et al.
The main aims for this study are as follows: (1) To determine whether degradation affects the ant communities; this was conducted by comparing ant composition diversity between degraded and control sites of a specific locality. (2) To determine whether rehabilitation periods influence ant communities by comparing the specific biodiversity index disparity between the localities with varying rehabilitation periods. (3) To identify which of these degradation activities impacted most on ant communities by comparing the specific biodiversity index disparity between the localities.
The MZNP (32.20500° S, 25.45000° E) is situated in the Eastern Cape province of South Africa (
The map showing the localities where ants were sampled from both degraded and control sites in Mountain Zebra and Mokala National Parks.
The MoNP (29.10350° S, 24.39410° E) is located in the Northern Cape province of South Africa. The dominant vegetation types are Kimberley Thornveld, Vaalbos Rocky Shrubland and Northern Upper Karoo (Bezuidenhout et al.
Twenty pitfall traps (100 mL plastic cups), each containing 50 mL of 50% propylene glycol–water solution (Adis
The biodiversity indices used to determine the composition of ant communities from each site were abundance, species richness, dominant species (i.e. the most abundant) and similarity (Anderson et al.
The difference between the degraded and control sites of each locality, for each biodiversity index, was compared with its counterparts from other localities. The differences were given a score ranging from 1 (for the least difference) to 5 (for the highest difference) (Roux et al.
This article followed all ethical standards for a research without direct contact with human or animal subjects.
All the degraded sites had lower abundance values than their controls (
Diversity indices of ants sampled on degraded and control sites from localities at the Mountain Zebra National Park and Mokala National Park.
Index values from the degraded and control sites of each locality and their disparity rankings relative to other localities.
Locality | Rehabilitation age |
Site | Abundance |
Species richness |
Shannon Diversity Index |
Simpson’s Index |
Dominant sp. similarity | Sorenson’s Coefficient |
Overall score | |||||
---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|
Value | Rank | Value | Rank | Value | Rank | Value | Rank | Rank | Value | Rank | ||||
Groenfontein | 1 | Degraded | 114 | 5 | 13 | 3 | 2.03 | 4 | 5.39 | 4 | 0 | 0.62 | 4 | 20 |
Control | 1837 | - | 16 | - | 1.76 | - | 4.18 | - | - | - | - | - | ||
uBejani | 12 | Degraded | 694 | 2 | 16 | 4 | 1.97 | 5 | 5.05 | 5 | 0 | 0.67 | 3 | 19 |
Control | 1230 | - | 20 | - | 1.47 | - | 2.77 | - | - | - | - | - | ||
Windpomp | 11 | Degraded | 685 | 4 | 17 | 1 | 2.08 | 3 | 5.29 | 3 | 0 | 0.71 | 2 | 13 |
Control | 1426 | - | 17 | - | 1.81 | - | 4.10 | - | - | - | - | - | ||
Juriesdam | 9 | Degraded | 294 | 1 | 11 | 3 | 1.20 | 1 | 2.08 | 2 | 1 | 0.42 | 5 | 13 |
Control | 708 | - | 8 | - | 1.15 | - | 2.56 | - | - | - | - | - | ||
Puntberg | 11 | Degraded | 1256 | 3 | 14 | 2 | 1.67 | 2 | 4.00 | 1 | 0 | 0.73 | 1 | 9 |
Control | 1921 | - | 16 | - | 1.82 | - | 4.37 | - | - | - | - | - |
, Number of years since the rehabilitation took place.
Species richness was lower at the degraded sites of Groenfontein, uBejani and Puntberg relative to their controls (
The Shannon–Wiener Diversity Index indicated that ant diversity was higher at the degraded sites of Groenfontein, Juriesdam, uBejani and Windpomp, and lowest at Puntberg (
The Simpson’s Index showed that Groenfontein, uBejani and Windpomp had higher dominance at the degraded sites, whilst the degraded sites of Juriesdam and Puntberg had lower dominance in relation to their control sites (
Although the degraded and control sites of most localities had similar dominating ant species (except Juriesdam and Windpomp) (
Species list of ants sampled from each locality with their abundance and indications stating their roles in dissimilarity contributions and exclusivity between the degraded and control sites.
Ant species | Groenfontein |
Juriesdam |
uBejani |
Windpomp |
Puntberg |
|||||
---|---|---|---|---|---|---|---|---|---|---|
Degraded | Control | Degraded | Control | Degraded | Control | Degraded | Control | Degraded | Control | |
3 | 10 | 41 | 107 | 126 | 679 |
10 | 361 |
408 |
0 | |
0 | 0 | 0 | 0 | 0 | 0 | 0 | 0 | 4 | 697 |
|
6 | 109 |
0 | 0 | 0 | 0 | 16 | 11 | 0 | 22 |
|
0 | 92 |
0 | 0 | 0 | 0 | 0 | 7 |
0 | 0 | |
0 | 3 |
0 | 0 | 0 | 0 | 0 | 2 |
17 | 12 | |
2 |
0 | 0 | 0 | 0 | 0 | 11 |
0 | 0 | 9 |
|
0 | 0 | 4 |
0 | 18 |
3 | 1 |
0 | 0 | 1 |
|
0 | 0 | 0 | 0 | 8 |
0 | 0 | 0 | 2 | 0 | |
0 | 0 | 0 | 4 |
1 | 43 |
0 | 0 | 0 | 0 | |
0 | 0 | 0 | 0 | 0 | 8 |
0 | 0 | 0 | 0 | |
0 | 0 | 0 | 0 | 3 |
0 | 0 | 0 | 0 | 0 | |
5 |
0 | 0 | 0 | 0 | 0 | 10 |
0 | 0 | 0 | |
21 | 283 |
3 | 192 |
10 | 34 | 10 | 5 | 2 | 5 | |
0 | 39 |
0 | 0 | 0 | 0 | 0 | 0 | 0 | 8 |
|
0 | 0 | 2 | 0 | 0 | 0 | 0 | 0 | 0 | 0 | |
0 | 0 | 0 | 0 | 0 | 2 |
0 | 0 | 0 | 0 | |
0 | 0 | 0 | 5 |
0 | 1 |
0 | 0 | 0 | 0 | |
0 | 0 | 0 | 0 | 0 | 0 | 9 | 27 |
8 | 37 | |
0 | 26 |
0 | 0 | 58 |
2 | 0 | 0 | 0 | 16 |
|
16 | 705 |
0 | 0 | 0 | 0 | 82 | 119 |
166 | 204 |
|
3 | 12 | 0 | 0 | 0 | 0 | 2 | 2 | 0 | 0 | |
0 | 2 |
0 | 0 | 0 | 0 | 0 | 0 | 0 | 0 | |
3 |
0 | 0 | 0 | 0 | 0 | 0 | 0 | 0 | 0 | |
0 | 0 | 198 | 384 |
100 | 262 |
0 | 0 | 0 | 0 | |
0 | 0 | 0 | 4 |
13 |
0 | 0 | 0 | 0 | 0 | |
0 | 0 | 0 | 0 | 0 | 22 |
0 | 0 | 0 | 0 | |
8 | 4 | 0 | 0 | 33 |
1 | 63 | 48 | 62 |
37 | |
0 | 0 | 0 | 0 | 0 | 0 | 113 | 117 |
90 |
85 | |
39 | 448 |
0 | 0 | 0 | 0 | 0 | 1 |
0 | 0 | |
0 | 0 | 18 |
0 | 0 | 0 | 0 | 0 | 0 | 0 | |
0 | 0 | 0 | 4 |
0 | 0 | 0 | 0 | 0 | 0 | |
0 | 0 | 8 |
0 | 247 |
103 | 0 | 0 | 0 | 0 | |
0 | 0 | 0 | 0 | 0 | 0 | 29 | 57 |
2 |
0 | |
0 | 0 | 12 |
0 | 5 | 4 | 248 | 573 |
431 | 509 |
|
0 | 1 |
0 | 0 | 0 | 4 |
0 | 9 |
0 | 0 | |
0 | 4 |
0 | 0 | 2 |
0 | 0 | 0 | 0 | 0 | |
0 | 0 | 1 |
0 | 0 | 0 | 0 | 0 | 0 | 0 | |
1 | 26 | 6 | 8 |
57 |
42 | 0 | 0 | 0 | 0 | |
6 | 73 |
1 |
0 | 7 |
0 | 25 |
21 | 2 | 34 | |
1 |
0 | 0 | 0 | 0 | 1 |
22 | 53 |
14 | 212 |
|
0 | 0 | 0 | 0 | 6 | 10 | 33 |
13 | 48 | 33 | |
0 | 0 | 0 | 0 | 0 | 2 |
0 | 0 | 0 | 0 | |
0 | 0 | 0 | 0 | 0 | 6 |
0 | 0 | 0 | 0 | |
Number of exclusive species | 4 | 7 | 7 | 4 | 5 | 8 | 3 | 4 | 3 | 5 |
Number of common species | 10 | 4 | 11 | 14 | 11 |
, Ant species that contributed ≥ 75% of the abundance in the site. The single dagger is located at the site where the species was more abundant.
, Ant species that were exclusively found at one site of the locality.
The low abundance and species richness at the degraded sites suggest that the treatments applied in the habitats were not supportive to ant communities (
We suggest that the lower biodiversity indices from the degraded sites (
The lower ant abundance at all the degraded sites, and the lower species richness at most of the degraded sites (
Differences between degraded and control sites suggest that time plays an important role in the rehabilitation process. Sites that had been recently rehabilitated, such as Groenfontein, had the highest overall differences, whilst the ones that had been rehabilitated before, such as Windpomp and Puntberg, had the lowest overall (
In addition to the time of rehabilitation, the type of degradation also influences the recovery (Vasconcelos
The type of degradation can sometimes have no direct impact on ants, as was seen at Puntberg, Juriesdam and Windpomp which have the least disparities between the sites and controls (see overall score in
Because this is only a preliminary study conducted during local drought conditions, we recommend further sampling when the rainfall is back to previous averages. We hope also that additional samplings could verify whether the differences still hold for all different sampled degradations.
In conclusion, we suggest that environmental authorities should consider the importance of the degradation types when acquiring lands for expanding conservation areas with consideration for brother organisms. As some of these degradation types seem to be persistent and take longer and more effort to be rehabilitated whilst others need lesser effort. They should also consider including different organisms when determining the degradation condition of the concerned conservation land. Including different organisms when assessing such land would inform the management as to how degraded is that land, in general, and therefore make the decision based on the assessment that would include different avenues.
SANParks and Biodiversity Social Projects in SANParks provided funding and manpower for this project.
The following people contributed immensely towards collecting data for this article: Clodene Ackerman, Pulane Daemane, Letlhogonolo Kotsokoane, Abel Matsapula, Phindile Mbele, Kelebogile Mohudi, Spencely Motloung, Mazwi Mthethwa, Shadi Ndouvhada, Lucky Ramabulana, Bruce Taplin and Nosidima Vumindaba. Laboratory space to identify ant specimen was provided by the Arid Lands Node of the South African Environmental Observation Network (SAEON) in Kimberley. The authors would like to thank the referees who reviewed the article.
The authors declare that they have no financial or personal relationships that may have inappropriately influenced them in writing this article.
H.S. was the project leader and responsible for sampling design, project implementation, data analysis and article writing. N.T. was responsible for project implementation, data analyses and article writing. H.B. and T.C.M. were responsible for article writing. L.M. was responsible for sampling.
SANParks and Biodiversity Social Projects in SANParks provided funding and manpower for this project.
Data sharing is not applicable to this article as no new data were created or analysed in this study.
The views and opinions expressed in this article are those of the authors and do not necessarily reflect the official policy or position of any affiliated agency of the authors.