| Literature DB >> 24155911 |
Ross Shackleton1, Charlie Shackleton, Sheona Shackleton, James Gambiza.
Abstract
Deagraianisation is a worldwide phenomenon with widespread social, ecological and economic effects yet with little consensus on the local or higher level causes. There have been contested views on the causes and consequences of deagrarianisation on South Africa's Wild Coast, which is an international biodiversity hotspot. Using GIS, household interviews and ecological sampling, we compared the perspectives of current and former cultivators as to why some have abandoned farming, whilst also tracking the uses and woody plant cover and composition of fields abandoned at different periods. The GIS analysis showed that field abandonment had been ongoing over several decades, with a decline from 12.5 % field cover in 1961 to 2.7 % in 2009. The area of forests and woodlands almost doubled in the corresponding period. There was a distinct peak in field abandonment during the time of political transition at the national level in the early 1990s. This political change led to a decrease in government support for livestock farming, which in turn resulted in reduced animal draught power at the household and community level, and hence reduced cropping. The study showed it is largely the wealthier households that have remained in arable agriculture and that the poorer households have abandoned farming. The abandoned fields show a distinct trend of increasing woody biomass and species richness with length of time since abandonment, with approximately three woody plant species added per decade. Most local respondents dislike the increases in forest and woodland extent and density because of anxiety about wild animals causing harm to crops and even humans, and the loss of an agricultural identity to livelihoods and the landscape.Entities:
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Year: 2013 PMID: 24155911 PMCID: PMC3796566 DOI: 10.1371/journal.pone.0076939
Source DB: PubMed Journal: PLoS One ISSN: 1932-6203 Impact factor: 3.240
Figure 1Comparison of land cover between 1961 and 2009 (n = 844 and 949, respectively).
Physical and vegetation attributes (mean + SE) of uncleared forests and fields with different lengths of abandonment (N = 55).
| Variable | Decade abandoned: | Statistics: | |||||||
|---|---|---|---|---|---|---|---|---|---|
| Forest | 1940s | 1950s | 1960s | 1970s | 1980s | 1990s | r | P | |
| Distance to nearest forest (m) | 0 | 6±41 | 108±108 | 158±96 | 183±212 | 150±40 | 300±125 | 0.3 | 0.37 |
| Altitude (m.asl) | 236±165 | 199±41 | 271±117 | 239±131 | 230±134 | 206±90 | 263±130 | 0.0 | 0.94 |
| Aspect (°) | 180±115 | 132±110 | 78±91 | 125±121 | 168±129 | 161±119 | 191±96 | 0.0 | 0.93 |
| Slope position | 3±0 | 3±1 | 3±1 | 2±1 | 3±1 | 4±2 | 3±2 | 0.3 | 0.85 |
| Slope angle (°) | 21±8 | 22±6 | 17±7 | 19±8 | 17±8 | 10±7 | 7±6 | 0.5 | 0.002 |
| Tree Density (no./200 m2 plot) | 198±38 | 227±43 | 355±245 | 143±48 | 154±116 | 73±36 | 45±37 | 0.4 | 0.008 |
| No. woody species (no./200 m2 plot) | 26±5 | 20±6 | 22±6 | 18±7 | 13±7 | 7±4 | 4±3 | 0.8 | <0.005 |
| Basal area (m2/ha) | 52±23 | 19±6 | 18±10 | 16±12 | 14±10 | 4±3 | 2±3 | 0.8 | <0.005 |
| Woody cover (%) | 98±3 | 83±5 | 81±42 | 54±22 | 45±26 | 17±15 | 10±12 | 0.8 | <0.0005 |
| Grass cover (%) | 1±1 | 20±6 | 27±19 | 60±28 | 59±28 | 69±24 | 81±9 | 0.8 | <0.005 |
| Herb cover (%) | 24±8 | 10±6 | 22±9 | 21±17 | 13±8 | 20±20 | 18±19 | 0.2 | 0.21 |
| Litter cover (%) | 50±14 | 44±11 | 28±12 | 19±16 | 15±14 | 4±4 | 6±5 | 0.8 | <0.005 |
| Bare ground cover (%) | 27±17 | 13±13 | 21±15 | 13±12 | 12±10 | 11±12 | 8±5 | 0.5 | 0.004 |
The relative density (%) of the most common woody species in forests and across fields with different abandonment dates (N=55).
(* alien invasive species) .
| Species | Decade abandoned: | ||||||
|---|---|---|---|---|---|---|---|
| Forest | 1940s | 1950s | 1960s | 1970s | 1980s | 1990s | |
|
| 0 | 2.7 | 5.6 | 18.1 | 24.3 | 54.4 | 83.9 |
|
| 6.5 | 0 | 0 | 0 | 0 | 0 | 0 |
|
| 3.2 | 0 | 3.4 | 0 | 0.04 | 0 | 0 |
|
| 2.2 | 0 | 0 | 1.23 | 0.2 | 1.3 | 1.1 |
|
| 1.1 | 11.1 | 16.3 | 12.7 | 8.9 | 9.3 | 1.5 |
|
| 0.2 | 2.1 | 2.1 | 2.1 | 4.4 | 2.6 | 4.1 |
|
| 3.9 | 12.3 | 11.9 | 8.4 | 6.2 | 4.3 | 0 |
|
| 2.9 | 7.5 | 4.9 | 6.3 | 2.9 | 2.2 | 0.3 |
|
| 5.7 | 0 | 0 | 0 | 0 | 0 | 0 |
|
| 2.9 | 16.7 | 12.6 | 13.0 | 25.9 | 15.9 | 3.0 |
|
| 1.3 | 1.8 | 1.1 | 4.3 | 2.2 | 5.6 | 1.1 |
|
| 7.7 | 0.7 | 0.9 | 0 | 0.3 | 0 | 0 |
|
| 5.5 | 0 | 0 | 0 | 0 | 0 | 0 |
|
| 0 | 3.7 | 0.5 | 0.4 | 0.3 | 0 | 0 |
|
| 4.6 | 0 | 0 | 0 | 0.1 | 1.4 | 0 |
|
| 0 | 0 | 3.2 | 0.4 | 3.1 | 0 | 0 |
|
| 8.6 | 6.4 | 3.7 | 0.6 | 2.7 | 0 | 0 |
|
| 0.9 | 10.4 | 2.7 | 3.9 | 2.3 | 0.2 | 0 |
|
| 4.4 | 5.1 | 3.2 | 5.7 | 2.2 | 2.2 | 1.5 |
Figure 2Shannon-Wiener species diversity change with time of field abandonment (forests set at 100 years) (n = 55).
Figure 3Detrended Correspondence Analysis (DCA) ordination diagram of plots for species composition in fields with different abandonment decades and intact forests.
(A = forests; B = 1940s and 1950s plots; C = 1960s; D = 1970s and 1980s; E = 1990s). (n = 55)
Soil characteristics (mean + SE) with age of abandoned fields and uncleared forests (N = 55).
| Variable | Decade abandoned: | Statistics: | |||||||||
|---|---|---|---|---|---|---|---|---|---|---|---|
| Forest | 1940s | 1950s | 1960s | 1970s | 1980s | 1990s | r | p | |||
| Organic carbon (%) | 4.0±0.6 | 4.3±0.7 | 3.4±0.9 | 2.9±0.9 | 2.8±1.0 | 1.8±0.7 | 1.6±0.6 | 0.7 | <0.001 | ||
| pH (KCI) | 4.8±0.7 | 5.4±0.2 | 4.9 ±0.5 | 4.7 ±0.5 | 4.8±0.4 | 4.6±0.2 | 4.6 ±0.6 | 0.2 | 0.214 | ||
| Exch acidity (cmol/l) | 12.5±34.2 | 0.2±0.0 | 0.2±0.1 | 0.5±0.5 | 0.7±0.8 | 0.2 ±0.1 | 0.3 ±0.1 | 0.3 | 0.058 | ||
| Acid saturation (KCI) | 9.5±9.7 | 2.0±0.0 | 2.1±1.0 | 8.0±9.1 | 7.3±8.0 | 3.4±1.9 | 5.2±2.1 | 0.2 | 0.223 | ||
| Total cations (cmol/l) | 7.7±1.4 | 9.7±1.6 | 7.6±1.3 | 7.3±2.3 | 6.9±2.1 | 5.7±2.3 | 5.6±1.7 | 0.3 | 0.014 | ||
| K (mg/l) | 114±53.1 | 164±36.2 | 101±31.4 | 130 ±21.0 | 103±36.5 | 69±40.9 | 133±119.7 | 0.1 | 0.451 | ||
| Ca (mg/l) | 858±403.7 | 1138±337.6 | 878±236.6 | 721±543.4 | 646±307.7 | 593±296.9 | 549±344.6 | 0.3 | 0.027 | ||
| Mg (mg/l) | 302±72.4 | 415±13.7 | 337±85.3 | 356±39.5 | 349±66.5 | 317±125.1 | 277±34.2 | 0.0 | 0.952 | ||
| P (mg/l) | 25.4±8.8 | 15.3±2.4 | 15.0±6.3 | 11.0±12.2 | 19.0±11.3 | 13.8±9.7 | 21.0±6.3 | 0.2 | 0.082 | ||
| Zn (mg/l) | 7.6±6.9 | 6.2±5.2 | 5.1±7.2 | 14.7±8.1 | 8.0±12.2 | 4.4±5.4 | 10.2±12.3 | 0.0 | 0.915 | ||
| Penetrometer | 2.5±0.8 | 3.0±1.3 | 4.0±0.7 | 4.2±0.3 | 4.1±0.5 | 4.4±0.2 | 4.0±1.2 | 0.7 | <0.001 | ||
Reasons why people have stopped cultivating (% of responses).
| Reason | Current cultivators (n=31) | Past cultivators (n=50): | |
|---|---|---|---|
| Free response | Prompted response | ||
| No cattle | 39 | 54 | N/A |
| Wild animals eat crops | 16 | 12 | 80 |
| Livestock eat crops | 0.0 | 22 | 80 |
| Lazy | 11 | 0 | N/A |
| Not enough equipment | N/A | N/A | 56 |
| Inputs too expensive | N/A | N/A | 56 |
| Not enough labour | N/A | N/A | 38 |
| Not worth it/ disinterested | N/A | N/A | 64 |
| Have enough food/income | N/A | N/A | 14 |
| Unpredictable weather | N/A | N/A | 20 |
| Exhausted soils | N/A | N/A | 24 |
The proportion (%) of current (n=31) and past cultivators (n=50) that collect NTFPs from three different land use types (N = 81).
| Resource | Forests: | Used and abandoned fields: | Grasslands and homesteads: | |||
|---|---|---|---|---|---|---|
| Current cultivators | Past cultivators | Current cultivators | Past cultivators | Current cultivators | Past cultivators | |
| Fuelwood | 97 | 92 | 64 | 64 | 0 | 0 |
| Wood for other purposes | 81 | 74 | 0 | 6 | 0 | 0 |
| Wild fruits | 84 | 74 | 0 | 2 | 0 | 4 |
| Wild vegetables | 0 | 4 | 51 | 6 | 87 | 94 |
| Bush meat | 45 | 20 | 0 | 0 | 0 | 0 |
| Thatch grass | 10 | 6 | 32 | 46 | 58 | 68 |
| Grass/stick brooms | 26 | 42 | 13 | 4 | 51 | 58 |
| Medicinal plants | 77 | 76 | 23 | 10 | 16 | 4 |
Reasons provided by current and past cultivators regarding why forests are increasing (N=74).
| Reasons | Proportion of responses (10 % and above): | |
|---|---|---|
| Current Cultivators | Past Cultivators | |
| (n=30) | (n=44) | |
| Less farming | 40 | 42 |
| Using less NTFPs | 30 | 44 |
| More rain | 11 | 10 |
| Invasive species | 10 | 0 |
| People moving to cities | 10 | 2 |
Widely mentioned woody species that establish first into abandoned fields as mentioned by current and past cultivators (N=81) (* = invasive alien species).
| Species | Current cultivators (%) (n=31) | Past cultivators (%) (n=50) |
|---|---|---|
|
| 100 | 88 |
|
| 36 | 20 |
|
| 19 | 14 |
|
| 13 | 12 |
|
| 0 | 22 |
|
| 19 | 0 |