Introduction
For millions of people around the world, forests are the vital basis of life for national economic development as well as a carbon sink that will later contribute to climate protection. In all respects the peoples of the world are dependent on either wood or other forest products. Obtaining individuals who are free from addiction to forest products is equivalent to obtaining electrons for free. The viability of restoration choices can be affected by the differences in ecological and socio-economic conditions, political and authentic settings, and level of management1. By excluding invasive species (negative factors in land restoration), land exclusion plays an important role in balancing the ecological and human foundations of life. Before establishing the exclusion, the surface/land should be scanned for pre-existing invasive alien species. Enrichment plantings should also be carried out after the introduced species have been checked for invasiveness. The establishment of restricted livestock areas or species protection support agricultural growth because they protect water catchment areas, stabilizes the local climate and the hydrological system. Community cooperation could be an essential ingredient for land restoration ventures to enhance the level of residential fulfilment and to progress its victory rate2. Nevertheless, there are socioeconomic and demographic components, which decide the level of interest in such projects. The absence of advantage from the preserved zone, level of education, and sexual orientation are among the basic variables of community interest in land reclamation. Therefore, this review paper is aimed to create awareness through providing information and documenting files on the socio-economic and soil nutrient improvement role of previously established exclosure land uses.
Development
Exclosure on soil erosion reduction and fertility improvement. In Ethiopia, inadequate agricultural practices such as cultivation on steep slopes, clearing of vegetation and overgrazing are the main factors leading to soil erosion and nutrient loss3-5. For instance, cultivation on the steep slopes in northern Ethiopia resulted in a loss of 35 tons of soil per hectare of land annually6. But today such a devastating loss of soil is being reduced by exclosures. For this reason, it was established as a form of land management with a spatial focus to improve environmental conditions and control soil erosion5,7.
The role of exclosure on soil fertility is measured through considering the availability of essential nutrient (micro and macro nutrient) for plant growth. Nitrogen (N), Phosphorus (P), Potassium (K), Sulfer (S), Calcium (Ca), Magnesum (Mg), Iron (Fe), Zinc (Zn), Manganese (Mn), Cuppor (Cu), Borun (B), Molybdenum (Mo), and Chlorine (Cl) are among the essential nutrient for plant growth8. Mekuria et al.9 and Conant et al.10 reported that variation in soil type, land-use history, land cover, climate, topography and vegetation cover creates difference in the content of soil organic carbon stock of a converted grazing lands (exclosure land). Due to such variability the contributions of exclosure for soil physical and chemical properties were studied in different way by different authors.
For instance, Abay et al.11 reported that converting open grazing land into an exclosure improved most soil properties except soil pH, avP and EC. They reported that exclosure had a significantly (p <0.05) higher SOC which shows an improvement of 46.5 or 61.3 % compared to grazing land. Besides, they said that, it increases CEC, TN and avK levels significantly (p <0.05) by 16.8, 45.5 and 34 %, respectively.
Mekuria and Aynekulu12 reported that the availability of N, P and CEC is varying with the age of exclosure and soil depth. They said that prevention of grass harvesting leads to raise the available soil P and N. Damene et al.13 also recently reported that management of degraded land by converting open grazing land to exclosure land with chomo grass sowing practice significantly enhances the total available N and SOC than open grazing lands (Table 1).
The presence of improved soil structure (high level of leaf litter and vegetation cover) in the exclosure land reduces the soil erosion better than open grazing land11,13.
Study done in the upper Blue Nile basin of Ethiopia shown that the use of area exclosure with trenches is a best option for soil erosion and runoff reduction14. While for soil loss reduction issue alone, use of area exclosure is suitable land management practices14. The improvement in canopy and ground cover in area exclosure with increasing age of exclosure reduces sediment associated nutrient loss through lowering raindrops and soil erosion4,12,15.
Macro and micro nutrients | Its availability in the exclosure land relative to adjacent open grazing land | Suggested reason | Reference |
---|---|---|---|
TN | Insignificant change ( but 0.45 times better than AOG land) | High SOC and legumes plant availability might enhance TN in the exclosure. | 7,11 |
avP | Insignificant change (but 0.15 times higher than AOG land) | 11 | |
avK | increase(0.34 times better than AOG land) | 11 | |
SOC | Increase(>0.5 times of open grazing land) | High litter fall from tree/shrub | 7,11,16 |
PH | No significant change is observed | Different temperature and rain fall varies SOM decomposition rate | 1,11 |
CEC | Insignificant change(but 0.16 times higher than AOG land) | Different temperature and rain fall varies SOM decomposition rate | 11 |
EC | Decrease (0.14 times lower than AOG land) | Might be due to high vegetation cover that optimize evaporation and infiltration | 11 |
CEC= Cat ion exchange capacity, EC=electric conductivity, TN= total Nitrogen, avP=available phosphorus, avK= available Potassium, SOC=soil organic Carbon.
Socio-economic impact of exclosure land. In this review paper, the socio-economic role of exclosure land focus on family size, gender, income, occupations, culture, perception and attitude of the society, educational status of the society. The contribution of forests to total household income in the northern highlands and southern Ethiopia was 27 % and 34 %, respectively17,18. Although such benefits are obtained, deforestation due to population pressures in Ethiopia is severe and has a long history, particularly in the central and northern highlands19.
To avoid such problems, the rehabilitation of degraded forests and woodlands by ecological and environmental viable (area exclosure and enclosure) land management practise is currently seen as a critical issues19,20. In addition to its role in regulating ecosystem services, the exclosure has socio-economic benefits for the livelihood of the community18,21-25. For example, the preservation of tree species in the vicinity of the church boundary is considered a heritage and offers spiritual benefits to society. Their role in demarcating the affected country and expressing the culture of a society is great as the facility requires less manpower26,27. The establishment of the exclusion had negative23,25 and positive4,28, attitudes towards the local community. Accordingly, the positive attitude of the local community is crucial for the sustainability of the exclosure and future rehabilitation measures.
The economic role of exclosure can be direct or indirect. Its direct role for the local community is expressed through the provision of animal feed, bee fodder, fuel and other non-wood forest products17,21 (Table 2). A study conducted in Biyo-Kelala Area Enclosures, Ada`a District, Eastern Shewa Zone, Oromoia Region, showed that income from exclosures was approximately 3.07 % of total annual household income29. The indirect benefits of excluser have also been achieved through improving land productivity and regulating environmental services30. Studies done in the semi-arid lowlands of northern Ethiopia showed that converting communal grazing land into exclosure land over 30 years was achieved the US $ 3.071 per hectare30. The conversion of the aboveground carbon stock into the monetary value of a relatively older excuser also creates a lot of economic benefit to a community and natural environment improvement. Conservation includes the preservation, maintenance, sustainable use, restoration and improvement of the natural environment. In this regard, Exclosure helps support the sustainable use of natural resources there by generating environmental, economic and social benefits for the rural communities31. This allows the local community to alleviate poverty by extending the vegetation cover on the degraded land.
Reviewed Socio economic parameters | Reference |
---|---|
Protect cultural heritage. | 32 |
Shelter to several wild animal. | 32 |
Act as esthetical value. | 32 |
Spiritual significance. | 32 |
Provision of fruit and medicine. | 33 |
Provides fodder for livestock. | 34 |
Improve hh (household) income. | 17,34 |
Create Job opportunity to hh (wild fruit collection, fodder sell, bee keeping, mushroom collection, guard, grass cut and carry). | 33 |
Improve the communal resource management skill of community. | 35 |
hh=household
Conclusion
Extensive dependence of rural household on the natural resource leads to resource degradation. Equitable resource distribution among end-users is important to sustainable forest land reclamation. Medicine, fuel wood, fruit, honey, aesthetic value, cultural value and spiritual uses were some of the socioeconomic uses of exclosure land to the rural households. Participation of local community on integrated soil erosion control practice in the exclosure land use enhances soil fertility when it is governed by local bylaws. Generally, the household who got benefit form land reclamation practice more motivated to protect other similar featured lands. In doing so, communities’ attitude towards exclosure land use improves with improved ecological systems. Further studies of the use of exclosure land use on gender, education level and age group should be done and documented for end-users. In addition to this studies on the equal distribution of resource to the community should be done to reduce conflict among exclosure land user households and get benefits sustainably. Studies on enhancing the advantage of local communities, their preferred tree/shrub, grass and spice species that should be planted in the exclosure land uses is also needed.