1. Introduction
1.1. Background of the study
Land degradation is a global problem threating human survival through the reduction of vital ecosystem services. It is known that degradation thresholds have been crossed in many habitats and natural succession alone cannot restore viable and desirable ecosystems without intervention by humans (Assefa et al., 2003; Aronson, 2005). Furthermore, the dispute of reversing the degradation of natural environments while meeting increasing demands for the natural resources has been dominating the development agenda of most developing nations, and necessitate significant changes in policies, institutions, and practices (United Nations Environment Programme, 1992 as cited in Meron, 2010).
The problem of land degradation becomes even more severe in loss of the upper most important fertile soil. This is because soil is a vital natural resource that is not capable of being renewed on the human time scale (Liu et al., 2006). It is a living and dynamic natural body that plays many key roles in terrestrial ecosystems, for instance, as sources of available nutrients to plants, maintenances in hydrological stability, and biological diversity. Conversion of natural landscapes into cultivated and grazing systems causes an abrupt decline in soil organic matter (SOM) and reduces the nutrient content of soil through reduced litter production, increased erosion rates, and decomposition of organic matter by oxidation (Chen and Xu, 2010).
Various reports (Solomon et al., 2002; Lal, 2005; Yimer et al., 2007) indicated that the conversion of natural forests to agricultural ecosystems negatively affects soil organic components concentration and stock by 20%–50%. Thus, mitigation strategies to reduce the impact of climate change (Food and Agriculture Organization, 2006) by augmenting carbon sequestration and reducing CO2 emissions from soils include proper forest management. Recently, establishment of exclosures to tackle the problem of land degradation has been practiced in the central and northern highlands of Ethiopia and is considered advantageous since it is a quick, cheap, and a lenient method for the rehabilitation of degraded lands. For example, it has become a common process to observe not only the acceleration of plant but also wild animal diversity with time, after the establishment of exclosures. For instance, establishment of area exclosures has been effective in Tigray especially with reference to diversities of woody flora and fauna increased, soil erosion decreased, and even dead springs started to flow after different exclosures were established (Emiru, 2002). With the same condition, in North Shewa zone, area exclosures provide fuel wood to meet the requirements of church, reduced surface runoff, increased infiltration, shades from the scorching sun for the clergy, and the laity during mass and religious festivals. The stems of the standing trees also give support to individuals during prayers and the trees add aesthetic value to the church (Abiyou et al., 2015).
In order to restore the degraded land area, a method called exclosure has been implemented in various parts of the central part of Ethiopia. However, there has been no comprehensive study conducted in this area to evaluate the impact of exclosure on soil qualities such as exchangeable cation, cation exchange capacity (CEC), organic matter, and soil moisture content (SMC). Additionally, it is important to recognize the positive contribution of exclosure to the local communities. Therefore, it is crucial to investigate the disparity in soil quality between exclosure areas and adjacent open grazing areas. Furthermore, it is essential to assess the local community’s perception of exclosure and its impact on their livelihoods. To achieve this, the following research questions were explored in this study: First, does exclosure improve soil quality (CEC, Ca, Mg, K, organic matter, and SMC) across the landscape following its implementation? Second, has the perception of the local community regarding exclosure and its contribution to their livelihoods changed after the introduction of exclosure? In order to answer these questions, specific objectives were set for this study: First, to examine the differences in soil quality before and after the implementation of exclosure. Second, to evaluate the perception of the communities in the central part of Ethiopia, regarding exclosure and its importance on their livelihoods.
The hypothesis put forward suggests the following: (1) There will be a notable enhancement in the overall soil quality within the exclosure area as opposed to the open grazing land; (2) The community holds a favorable perception toward the exclosure area and has experienced greater advantages from the establishment of the exclosure in central part of Ethiopia.
2. Materials and methods
2.1. Description of the study areas
The research was carried out in central part of Ethiopia and the watershed was purposefully chosen for this study in the central part of Ethiopia that featured both adjacent area exclosure and open grazing land. Geographically, stretches from 10°44′15″N to 10°73′43″N Longitude and 39°68′82″E to 39°92′48″E Latitude (Figure 1). The study area displays noticeable variations, consisting of flat low lying plains surrounded by mountainous regions. The altitude in this area ranges from 1,568 to 3,532 m above sea level.
Figure 1.Location map of the study area.
The region is primarily characterized by two significant types of soils namely liptosols and vertisols (Abiy, 2010). It is also classified within the agro-ecological zone of moist Weina Dega, where the temperature varies between 18.6°C in autumn/winter and 25.0°C in spring/summer seasons (Figure 2). The area experiences both short and long spells of rainfall, with an average annual precipitation ranging from 800 to 1,500 mm. However, the majority of rainfall is concentrated during the summer season. To illustrate, the period from June to September is considered the long rainy season, while February to April is characterized by a shorter rainy period.
Figure 2.Average monthly temperature and rain fall (2007–2022) of study area.
The agricultural endeavors conducted in the region primarily encompass the production of crops and the husbandry of animals, with the latter serving as a complementary aspect. Farms serve as a highly efficient agricultural system, with the mixed-farming technique prevailing as the dominant approach. Cultivated areas and woodlots, consisting of Acacia lahai and Croton macrostachyus trees, represent the prevailing land use and land cover types. The principal crops cultivated for sustenance and income generation consist of teff, maize, sorghum, and, to a lesser extent, wheat and barley. During the long rainy season, farmers grow wheat, chickpea, teff, barley, sorghum, and maize. Among these, teff and sorghum dominate the upper part of the research area. The main livestock raised by the local inhabitants in the watershed include cows, oxen, sheep, goats, and chickens.
The vegetation cover was dominated by scattered trees and shrubs in the area around settlements, but tree, shrubs, and grass on farmlands. Eucalyptus spp., Acacia lahai, Croton macrostachyus, and Acacia abyssinica are the dominant trees that are grown in the fields mainly for income generation from the sale of poles and fuel wood. They are important cash sources for the local communities in the study site. The open free-grazing field is dominated by natural grown woody species including Rhus natalensis, Euclea schimperi, and Carissa edulis. The exclosure was established for the aim of rehabilitating the degraded site. The main contributors for the establishment were nongovernmental organizations and local people.
2.2. Research methodology
To ensure the ethical conduct of our survey research, we prioritize human subjects’ protections by obtaining informed consent, maintaining participant confidentiality, and minimizing any potential risks associated with participation. The study was structured in response to the information gathered about the location. It aimed to collect data on the soil in the exclosure and open grazing site, as well as the opinions of the community regarding the establishment and management of the exclosure. The exclosure was established in 1977 E.C. (about 33 years prior to our study) for the aim of rehabilitating the degraded site. The selection of these two sites was based on the assumption that they possessed comparable soil types and slope gradients. This decision was influenced by the fact that the exclosure and open grazing site shared a similar historical background before the exclosure was established. However, the changes between the two sites could be described using physical and chemical constituents of the prevailing soils (Mengistu et al., 2005; Mekuria et al., 2007).
After conducting an initial survey, comprehensive information regarding the soil composition and community perception was gathered. Utilizing the GARMIN 72H GPS, the precise positions of each plot were identified, enabling the recording of both coordinates and altitudes. To ensure convenient placement of the sample plots along each line transect, circular shapes were adopted for each individual plot. Previous studies also noted that circular plots minimize the number of border trees (i.e., reducing edge effect) because of smaller circumferences to area ratio, in comparison to square and rectangular quadrants (Kibret, 2008).
The process of gathering information from the community was carried out through the creation of well-organized questionnaires. These questionnaires were thoughtfully designed, taking into account different aspects such as demographics (including gender, age, and family size), socioeconomic factors (such as education level, occupation type, annual income, ownership of livestock, benefits received from area closure, length of residence in the area, future plans for residency, and interest in expanding livestock ownership), and institutional factors (including ownership of private land, proximity of farmland to grazing areas, and adherence to local bylaws). Building upon the research conducted by Tadesse and Tafere (2017) as well as Tadesse and Teketay (2017), various demographic, socioeconomic, and institutional aspects were evaluated using a nominal scale. To determine the responses, specific questions were selected.
The scale employed a rating system wherein 3 denoted “yes,” 2 represented “unsure,” and 1 indicated “no.” Furthermore, several key factors such as age, family size, annual income, and level of education were gauged using continuous quantitative values. To reflect the gender of the respondents, a dummy variable was introduced. It was given a code of 1 for males and 2 for females.
The study measured the data on flood hazards, crop yield improvement, local bylaws, availability of fuel wood, and knowledge on plant species regeneration used for medicinal or fodder purposes before and after the establishment of the area exclosure. Additionally, the respondents shared their personal experiences and knowledge pertaining to the area exclosure through open-ended questions.
2.3. Methods of data collection and analysis
2.3.1. Soil data collection
Soil samples were collected from different management areas by taking samples from four directions (north, south, east, and west) in a circular pattern around a sample plot. These samples were taken at a distance of 10 m from the center, as well as one sample from the center itself. All samples measured 1 × 1 m2 in size (Figure 3). To collect the samples, each designated plot was excavated, and soil samples were collected from a depth of 0–20 cm using a soil auger. The collected soil samples from each plot were then mixed together, resulting in a composite soil sample weighing 1 kg. This composite soil sample was carefully placed in a labeled plastic bag. Each sample point had its own bag, ensuring that there was no mixing between the two different management areas. In addition to the composite soil samples, undisturbed soil samples were also collected using a core sampler. These samples were specifically collected to determine the soil bulk density and SMC. The collection of undisturbed was done separately for each land use type. It is important to note that the analytical results obtained from the composite soil sampling provide an average value for the sampled site. The various soil variables that were analyzed in the laboratory included SOM, soil pH, soil texture, total Nitrogen (N), available phosphorus (P), exchangeable cations such as Magnesium (Mg2+), sodium (Na+), potassium (K+), and calcium (Ca2+), as well as CECs, soil bulk density, and SMC.
Figure 3.Plot size and quadrants for the soil sample.
2.3.2. Household survey
In order to enhance the quality of information gathered from the study location and determine the specific type of data to be collected, a preliminary survey was undertaken. Drawing upon the work of Israel (1992), the overall sample size for this study was calculated employing the subsequent formula:
where n = sample size, e = confidence level, N = total household.
According to the aforementioned formula, a total of 89 households were included in the sample, with a confidence level of 90%. To assess respondents’ understanding, beliefs, and perspectives on “exclosure and its impact on soil quality improvement,” a semi-structured questionnaire incorporating both open-ended and closed-ended questions was devised and administered. Random sampling was deemed appropriate to gather demographic, socioeconomic, and institutional information. This method ensures unbiased selection as all households within the study area have an equal opportunity to be chosen (Israel, 1992; Tadesse and Kotler, 2016; Tadesse and Tafere, 2017; Tadesse and Teketay, 2017; Tafere and Nigussie, 2018). The households were selected randomly through a lottery system utilizing their identification numbers. Trained enumerators conducted the questionnaire survey by personally visiting each household. The independent variables in this study were obtained from a set of 21 questions.
These questions covered various aspects such as demographic information, socioeconomic factors, and local knowledge about the area. The variables included sex, age, family size, education level, occupation type, annual income, residency in the area, settlement history, future plans to stay in the area, livestock ownership, desire to increase livestock in the future, availability of grazing land, ownership of private land, awareness of flood hazards prior to the establishment of the area exclosure, knowledge of crop yield improvements after the establishment of the area closure, adjacency of farmland to grazing areas, familiarity with the establishment of the area exclosure, awareness of local bylaws, accessibility of fuel wood after the establishment of the area exclosure, benefits obtained from the area exclosure, and knowledge of plant species regeneration for medicinal or fodder purposes after the establishment of the area exclosure. On the other hand, the dependent variable in this study was based on the perception of the local communities toward the exclosure of the area for the purpose of rehabilitating degraded land in the study area.
2.3.3. Data analyses
2.3.3.1. Soil data analyses
The soil samples obtained from the two different land use areas were carefully analyzed at the Debre Berhan Research Center using laboratory techniques. In order to determine the soil bulk density, the core method was employed. This involved calculating the mass of soil that had been dried in an oven at a temperature of 105°C and dividing it by the corresponding volume (Chen et al., 2010)
1where ρb = soil bulk density (g cm−3), Ms = mass of soil after oven dry (g), Vb = bulk volume of the soil (cm−3).
The measurement of SMC was conducted in accordance with the procedure outlined in Cuenca’s study (1989). The initial weights of the soil samples were recorded before they underwent drying in an oven. Subsequently, the samples were subjected to 24 h of drying at a temperature of 105°C. A beam balance was employed to weigh the samples after the drying process. The moisture content of the soil samples was then determined utilizing the subsequent formula.
2where MC = soil water content, Wwet = the weight of the wet soil sample (g), and Wdry = the weight of the oven-dried soil sample (g).
Soil pH was measured with a digital pH meter in a suspension of 1:2.5, soil to water suspension following Carter (1993). Soil texture was determined by hydrometer method (Gee and Baunder, 1986). The determination of organic matter follows Walkly and Black (1934). Total nitrogen was determined following Kjeldahl digestion (Kjeldahl, 1883). Available phosphorus was determined by using Bray No-II (Bray and Kurtz, 1945). An ammonium acetate extractant method was used to analyze the exchangeable cations (Ca2+, K+, Mg2+, and Na+) and CEC (Schollenberger and Simon, 1945).
The data acquired from the analysis of the soil underwent an Analysis of Variance (ANOVA) process using the SPSS software (version 20) to evaluate the differences among different types of land use. In this comparison, the land use type was considered as the independent variable, while the variables that could potentially be affected included SOM, bulk density, SMC, exchangeable cations, CEC, total nitrogen, available phosphorus, and organic carbon. To interpret the soil analysis results, descriptive statistics such as means and variances were employed. Additionally, mean comparisons were conducted with a significance level set at P < 0.05.
2.3.3.2. Socioeconomic data analyses
The socioeconomic data that were collected through the social survey were coded in a computer, and then analyzed to extract meaningful information. Descriptive statistics, such as mean, percentage, standard deviations, and frequency, were quantified. A multiple linear regression model was used to predict effect of the independent variables on the dependent variable, that is, perception of local people toward “exclosure” (Tadesse and Kotler, 2016; Tadesse and Teketay, 2017).
After accounting for multiple comparisons (21 tests per dependent variable) with a Bonferroni correction, P ≤ 0.002 was considered significant. We computed the Bonferroni correction by dividing 0.05 to 21 which is equal to 0.002. This is because Bonferroni correction is a safeguard against multiple tests of statistical significance on the same data falsely giving the appearance of significance (Morzillo et al., 2007). All the analyses were conducted using Statistical Package for Social Sciences (SPSS) version 20.
3. Results and discussions
3.1. Chemical properties of the soil
There was a noticeable difference in the pH levels of the soil between the two management areas. The pH of the soil in the areas that had been area exclosure (7.46 ± 0.04) was significantly (P < 0.05) higher than in the open grazing land (7.11 ± 0.03). This difference can be attributed to the accumulation of exchangeable cations in the area exclosure.
One key finding of the study was the significant variation in exchangeable cations of soil variables at a depth of 20 cm between different management areas. Notably, exchangeable Ca2+, exchangeable Mg2+, and exchangeable K+ were all found to be higher in the exclosure compared to the open grazing land (Table 1). Furthermore, the exclosure exhibited higher overall mean values of exchangeable Na+ and showed significant differences in total N, available P, cation-exchange capacity, organic carbon, and organic matter when compared to the open grazing land (Table 1).
Table 1.Chemical properties of the soil on area exclosure and open grazing sites
| Soil Variables | Unit | Exclosure | Open | F value | P Value |
|---|---|---|---|---|---|
| Soil pH (1:2.5) | 7.46 ± 0.04a | 7.11 ± 0.03b | 40.17 | 0.000 | |
| Soil cation-exchange capacity | meq/100 g | 44.44 ± 0.67a | 38.18 ± 0.86b | 33.46 | 0.000 |
| Exchangeable Na+ | meq/100 g | 0.76 ± 0.06a | 0.67 ± 0.05a | 1.42 | 0.239 |
| Exchangeable K+ | meq/100 g | 1.24 ± 0.10a | 0.57 ± 0.06b | 33.16 | 0.000 |
| Exchangeable Ca2+ | meq/100 g | 27.58 ± 0.65a | 24.91 ± 0.68b | 10.79 | 0.002 |
| Exchangeable Mg2+ | meq/100 g | 10.66 ± 0.35a | 7.94 ± 0.31b | 33.43 | 0.000 |
| Available P | ppm | 12.85 ± 1.14a | 8.25 ± 0.60b | 12.65 | 0.001 |
| Total N | % | 0.35 ± 0.02a | 0.14 ± 0.01b | 55.63 | 0.000 |
| Organic C | % | 3.02 ± 0.12a | 1.55 ± 0.12b | 75.21 | 0.000 |
| Soil organic matter | % | 5.19 ± 0.20a | 2.67 ± 0.21b | 74.97 | 0.000 |
| C/N | 8.63 | 11.07 |
The number labeled with different superscript letters at area exclosure and open grazing land were significantly differed at P < 0.05 level significant.
Previous studies have also supported these findings, indicating that the conversion of open grazing land to exclosure has led to increased values of total soil N stocks, available P stocks, and CEC. These values were found to be positively correlated with woody biomass, vegetation canopy cover, and clay content, but inversely correlated with bulk density (Mekuria and Aynekulu, 2011).
Similarly, Chen and Xu (2010) have reported that the conversion of natural landscapes to grazing systems results in a decline in SOM and a reduction in nutrient content due to decreased litter production and increased soil erosion rates. This is further supported by studies conducted in northern Ethiopia, where grazing land exhibited lower levels of N, P, and CEC in comparison to exclosure areas (Mekuria et al., 2011). Similar findings have also been reported in tropical pastures (Ajorlo et al., 2011).
However, when considering the overall average pH of the soil, it was found that the exclosure had a significantly higher pH compared to the open grazing site. This difference could possibly be attributed to the build-up of organic matter within the exclosure, leading to an increase in base cation concentration. Previous studies have also mentioned the potential for organic matter build-up to reduce soil erosion, thereby increasing the presence of soluble base cations (such as Ca2+ and Mg2+). These cations subsequently neutralize the H+ ions responsible for acidity and consequently elevate the pH levels in the soil (Yimer et al., 2015). Significant variations were observed in the exchangeable cation of soil variables at a depth of 20 cm between management areas. Specifically, exchangeable Ca2+, exchangeable Mg2+, and exchangeable K+ were all found to be higher in the exclosure area compared to open grazing land (Table 1). This can be attributed to the greater accumulation of organic matter resulting from the decomposition of plant materials, which plays a vital role in enhancing the soil’s physical and chemical fertility (Charman and Roper, 2007).
3.2. Physical properties of soil
The distribution of soil particle size fractions, namely sand, silt, and clay, exhibited significant variations across different management areas as indicated in Table 2. Notably, the average proportion of sand particles in the open grazing land was considerably higher (59.87 ± 3.62) compared to the exclosure area (39.66 ± 2.13). Conversely, the exclosure area demonstrated significantly higher percentages of silt (25.33 ± 0.66) and clay (35.00 ± 1.90) compared to the open grazing land (21.20 ± 1.14, 18.93 ± 2.62, respectively).
Table 2.Physical properties of the soil on exclosure and open grazing sites
| Soil Variables | Unit | Exclosure | Open | F value | P Value |
|---|---|---|---|---|---|
| Moisture content | % | 16.38 ± 0.49a | 12.69 ± 0.71b | 18.38 | 0.000 |
| Bulk density | g/cm−3 | 0.97 ± 0.02a | 1.22 ± 0.03b | 54.57 | 0.000 |
| Sand | % | 39.66 ± 2.13a | 59.87 ± 3.62b | 22.56 | 0.000 |
| Silt | % | 25.33 ± 0.66a | 21.20 ± 1.14b | 9.83 | 0.003 |
| Clay | % | 35.00 ± 1.90a | 18.93 ± 2.62b | 24.12 | 0.000 |
| Texture | Clay loam | Sandy loam |
The number labeled with different superscript letters at area exclosure and open grazing land were significantly differed at P < 0.05 level significant.
The soil’s bulk density and moisture content exhibited significant variability due to differences in management significantly (i.e., area exclosure and open grazing land). Open grazing land displayed a higher soil bulk density of 1.22 ± 0.03 compared to the exclosure which had a lower bulk density of 0.97 ± 0.02 (Table 2).
There was a noticeable contrast in the level of soil moisture between the two types of management areas. Specifically, the exclosure area had a higher moisture content of 16.38 ± 0.49, compared to the open grazing land which had a lower moisture content of 12.69 ± 0.71 (Table 2). However, the open grazing land experienced a higher rate of erosion due to excessive grazing and trampling by livestock. These activities also had an impact on the overall condition of the watershed by altering the plant cover. Similarly, Bezabih et al. (2014) stated that removal of ground cover by open grazing of livestock has been considered as one of the main causes of soil erosion.
Specifically, the average sand fraction in open grazing lands was found to be significantly higher compared to exclosure areas. On the other hand, the silt and clay soil fractions were significantly higher in exclosure areas compared to open grazing lands. This difference can be attributed to the process of soil erosion, which leads to the removal of clay and silt soils from open grazing lands due to the absence or scarcity of vegetation cover in those areas. Yimer et al. (2015) suggest that the predominance of sand size fraction can be attributed to the selective transportation of fine particles by soil erosion.
Another study conducted by Valckx et al. (2002) found that open grazing lands experience a high degree of erosion, primarily due to the reduction in vegetation cover resulting from over grazing and the cutting of fuel wood. Overall, this study highlights the significant role of area exclosure in improving soil quality and draws attention to the impact of land use practices, such as open grazing, on soil erosion and the physical properties of the soil.
There were notable variations in the bulk density and moisture content of the soils, which were attributed to differences in soil management practices. The open grazing land displayed significantly higher soil bulk density compared to the exclosure. This difference can likely be attributed to soil compaction resulting from trampling by livestock, as well as a lower vegetation cover leading to decreased organic matter content. A previous study also observed that the absence of vegetation cover in open lands contributes to higher soil crusting and sealing, which subsequently increases bulk density (Tizita, 2016).
Similarly, a notable disparity in SMC was observed between the two types of land use. The exclosure exhibited higher moisture content compared to the open grazing land. One potential explanation for this phenomenon could be attributed to the dense vegetation cover in the exclosure, along with the increase in organic matter resulting from the decomposition of fallen litter. In particular, organic matter plays a crucial role in enhancing soil structure and promoting aggregate stability. This, in turn, leads to an amplification of pore size and ultimately facilitates a higher rate of water infiltration through the soil aggregates. Additionally, the presence of a greater proportion of clay soil and organic carbon in the exclosure contributes to the elevated moisture content of the soil. The augmented organic carbon content enhances soil moisture by improving its structure (Mganga et al., 2011). Conversely, the open grazing land experiences a higher erosion rate due to excessive livestock grazing and trampling. These practices also have a detrimental impact on the vegetation cover, thereby affecting the properties of the watershed. Previous investigations have also highlighted that a reduction in vegetation cover can intensify the impact of raindrops, decrease SOM, disrupt soil aggregates, promote surface crust formation, and diminish soil water content (Mwendera et al., 1997).
3.3. Perception of local peoples on area exclosure
The perception of the local population regarding the management of natural resources plays a crucial role in the success of conservation efforts. A significant majority of the individuals surveyed, accounting for approximately 76% of respondents, demonstrated awareness regarding the establishment of area exclosure. Furthermore, over half of the participants, approximately 62.9%, attributed an observable increase in the rejuvenation of plant biodiversity subsequent to the implementation of the exclosure initiative.
To illustrate, a significant portion of the participants, specifically 83%, argued that the introduction of community-based participatory methods for conserving biodiversity, and 41% argued that strict enforcement of laws, along with punishments for those engaging in illegal activities within the boundaries of the exclosure, were the primary factors contributing to the positive trend of plant biodiversity following its establishment.
In terms of knowledge regarding local regulations formulated through consensus among the community, about 76% of respondents were aware of the presence of such bylaws. As per these regulations, anyone caught trespassing with their livestock within the exclosure area would face penalties amounting to 50 birr per sheep or goat, 100 birr per ox or donkey, and 200 birr per camel. The effectiveness of these bylaws was recognized by approximately 74% of participants. More than half of them observed a positive trend in the restoration of plant biodiversity following the implementation of these exclosures. Previous research has also recognized the contribution of these exclosures in promoting the regeneration of plant biodiversity (Yami et al., 2006; Mekuria and Aynekulu, 2011).
However, there remain challenges to effective management of the exclosure. Unequal distribution of resources, such as grass and fuel wood, from within the exclosure area, and unauthorized activities such as tree cutting, unrestricted grazing by livestock, and unauthorized collection of fuel wood pose significant threats. Based on responses gathered through household surveys, local inhabitants expressed concerns about the negative impact of exclosures on the expansion of farmland (5%), limitations on access to fuel wood (20%), and competition for grazing land (47%).
In addition to their monthly salaries, the guards are permitted to let one camel graze freely without any time restrictions. They are also allowed to collect dead branches at their convenience. The guards, who are chosen from the local community, are responsible for safeguarding the exclosure. It is strictly prohibited to gather fuel wood, chop down trees, or harvest grass within the exclosure, as stated by the bylaws established by the local residents. The local respondents argue that these bylaws have proven to be effective. However, several issues persist, such as the uneven distribution of resources from the exclosure, particularly grass and fuel wood. These activities pose significant management challenges and jeopardize the integrity of the exclosure. Similar studies conducted by Meron (2010) indicate that the insufficient incentives for guards, weak enforcement of rules, and inadequate monitoring measures are obstacles that hinder the realization of optimal benefits from exclosures.
The greater positive perception of local people toward exclosure may be connected with the ample indigenous knowledge about exclosure, and large number of the participants (90%) affirmed that they have experienced numerous advantages as a result of the exclosure. They perceived benefits (employment opportunities, infrastructure development, wood products, source of fodder for livestock through cut and carry system, etc.) and values (aesthetic and medicinal values) that the local people expect from the exclosure in the study areas. Tessema et al. (2007) stated that the local communities’ viewing of exclosure and the associated vegetation diversity and its value make them more excited than anything else. Similarly, Roskaft et al. (2007) noted that people who feel enjoyment at the prospect of seeing large coverage of vegetation. Among all respondents, approximately 93% observed a reduction in the occurrence of flood hazards following the establishment of the area exclosure. This thought was also supported by Abera et al. (2016), who studied around East Shewa Zone, Adami Tulu Jido Kombolcha District, and stated that the establishment of exclosure has benefits to reduce flood hazards and also change the local weather through microclimate regulation.
3.4. Socioeconomic factors that affect perception of the local community
The multiple linear regression analysis demonstrated that several socioeconomic factors had a significant impact on the perception of local residents toward the concept of exclosure. Upon examining the coefficients, it was observed that individuals who were older (ß = 0.23), more educated (ß = 0.25), had resided in the area for a longer period of time (ß = 0.19) were aware of flood hazards prior to the establishment of the exclosure (ß = 0.20), knew about the establishment of the exclosure (ß = 0.18), were aware of the regeneration of plant species used for medicinal or fodder purposes after the establishment of the exclosure (ß = 0.21), and had knowledge of local bylaws (ß = 0.18), as well as private land ownership (ß = 0.27), had a significantly positive perception toward exclosures. On the other hand, females (ß = −0.18) and daily laborers (ß = −0.23) had a significantly negative perception toward the exclosure. In summary, the multiple linear regression analysis revealed that socioeconomic variables had a significant impact on the dependent variable, which was the perception toward the exclosure, explaining 29% of the variance (Table 3).
Table 3.Multiple linear regressions model to predict perception toward the exclosure, + indicates a positive change in perception and − a negative change in perception
| Perception Toward the Exclosure | |||
|---|---|---|---|
| Variable | ß | t | P value |
| Intercept | — | +28.57 | 0.000 |
| Sex | −0.18 | −1.98a | 0.002 |
| Age | +0.23 | +2.21a | 0.002 |
| Family size per household | −0.15 | −1.49 | 0.141 |
| Level of education | +0.25 | +2.41a | 0.001 |
| Occupation | −0.23 | −2.21a | 0.002 |
| Annual income | +0.09 | +0.85 | 0.398 |
| Lived in the area | +0.19 | +2.13a | 0.002 |
| History of settlement | +0.02 | +0.16 | 0.881 |
| Plan to stay in the area in the future | −0.04 | −0.36 | 0.722 |
| Livestock ownership | +0.09 | +0.90 | 0.373 |
| Want to keep more livestock in the future | +0.06 | +0.59 | 0.562 |
| Enough grazing land | +0.16 | +1.57 | 0.121 |
| Private land | +0.27 | +2.60a | 0.001 |
| Flood hazard before the establishment of the area closure | +0.20 | +2.23a | 0.002 |
| Increment of crop yield after the establishment of the area closure | +0.01 | +0.06 | 0.951 |
| Farmland adjacent to grazing area | +0.14 | +1.39 | 0.172 |
| Establishment of area exclosure | +0.18 | +2.13a | 0.002 |
| Presence of local bylaw | +0.18 | +2.72a | 0.001 |
| Accessibility of fuel wood after the establishment of the area exclosure | −0.04 | −0.33 | 0.743 |
| Benefited from area exclosure | +0.01 | +0.09 | 0.93 |
| Knowledge on the regeneration of plant species used for medicinal or fodder purpose after the establishment of the area exclosure | +0.21 | +2.34a | 0.002 |
Standardized coefficients were reported.
aRepresents significance at the 95% confidence level; Adj. R2 = 0.29, df = 20; F = 3.19, P < 0.001.
A study conducted by Solomon and Demel (2017) in the Tarmaber District of North Shewa Zone found that socioeconomic factors also significantly influenced the perception of local residents toward participatory forest management. Overall, the local residents exhibited a more positive perception toward the exclosure. For instance, a majority of respondents agreed (69%) or strongly agreed (25%) with the presence of the exclosure, while only a small percentage disagreed (7%).
Based on the data collected from a selection of households, it was discovered that the amount of fodder obtained from the exclosure for thatching purposes decreased as the exclosure aged. This decline can be attributed to the growing number of trees and shrubs, which resulted in excessive shading, which affected the growth of undergrowth vegetation, including the grasses used for thatching. These findings align with a previous study conducted by Kibret (2008) in the Kallu District, Southern Wello, where it was observed that after 5 years, exclosures experienced a reduction in grass production due to the canopy cover of certain plant species, particularly thorny species from the Fabaceae family.
4. Conclusion
This study has presented compelling evidence regarding the beneficial effects of exclosure on soil quality improvement. Additionally, it aimed to investigate the perception of the community toward exclosure areas in central part of Ethiopia. The findings of this study demonstrate that the exclosure area exhibited significantly higher levels of soil nutrients, including exchangeable calcium, magnesium, and potassium. Furthermore, the exclosure site displayed enhanced CEC, total nitrogen content, availability of phosphorus, SOM, and organic carbon compared to the open grazing site. These results suggest that limiting human and livestock interference through exclosure implementation can effectively facilitate the rehabilitation of degraded areas. Consequently, this restoration process enables the revival of natural vegetation and promotes an increase in plant species composition, particularly woody plants. Moreover, exclosure intervention contributes to the amelioration of soil quality by augmenting vegetation coverage, thereby reducing soil erosion and minimizing the risk of flooding in and around the study site.
The results of the multiple linear regression model demonstrated that various socioeconomic and demographic factors, including gender, age, education level, occupation, duration of residence in the area, ownership of livestock and land, and awareness of flood hazards before the establishment of the exclosure, had a significant impact on the perception of local residents toward the exclosure. However, the findings of this study suggested that the knowledge, experience, and perception of the local community regarding the contributions of the exclosure to biodiversity conservation, soil quality enhancement, and socioeconomic development might change over time.
The study also highlighted that the main challenges faced by the exclosure in achieving its objectives, such as promoting vegetation diversity and improving soil quality, were illegal interventions by local individuals and their livestock. To improve the perception of local residents toward the exclosure, it is crucial to increase their knowledge. Therefore, providing conservation education to the local communities and advocating for the importance of sustainable utilization can help enhance positive perception and increase the support of the local community in the conservation and management of the exclosure. Additionally, informing the local residents about the aesthetic, ecological, and economic values of the exclosure can contribute to this positive change.
Finally for effective improvement of soil quality within exclosures, measures should be taken to minimize disturbances caused by human activities. Emphasis should be placed on preventing livestock from accessing these areas. Additionally, planting suitable vegetation can aid in the regeneration of woody plant species within the area exclosure, thereby reducing erosion risks, particularly for fertile topsoil, and increasing the soil’s ability to retain moisture. It is also crucial to promote and strengthen the traditional bylaws that were historically employed by local farmers to prevent unauthorized entry into exclosures by people or livestock.
Data accessibility statement
The data supporting the findings of this study are included with this manuscript as supplementary files.
Supplemental files
The supplemental files for this article can be found as follows:
Supplementary Data 1–4. Docs
Acknowledgments
We would like to extend our heartfelt gratitude to the experts at the District Agricultural Office for their cooperation. Their valuable information and assistance were insturumental in helping us conduct the interview.
Funding
This research did not receive any specific funding.
Competing interests
The author(s) declared no potential conflicts of interest with respect to the research, authorship, and/or publication of this article.
Author contributions
Aweke Worke Beyene processed and analyzed the data, performed data interpretation, and drafted the first version of the manuscript. Mekuria Argaw Denboba revised and edited the manuscript. Alebachew Shumye Moges revised and amended the manuscript.
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1 Department of Natural Resources Management, College of Agriculture and Natural Resource Sciences, Debre Berhan University, Debre Berhan, Ethiopia
2 Department of Environmental Science, College of Natural and Computational Sciences, Addis Ababa University, Addis Ababa, Ethiopia