Participatory land-use planning and conservation in northern Tanzania rangelands

In developing countries, participatory land-use planning is seen as a panacea to mitigate land-use conflicts and enhance land productivity. This assumption has not been thoroughly tested in wildlife corridors. Three villages were selected for this study. Several methods were used to provide indication of the performance of the plans against their stated objectives of mitigating conflicts and conserving wildlife corridors. Three hundred and fifty-eight households and eight park and extension workers were interviewed. In addition, focus group discussion with the nomadic Barabeig, field assessment and review of land-use plan/general management plan reports were carried out. Results reveal that land-use plans failed to achieve their set objectives. For example, 75% of the households held this view. Major causes of failure were insufficient participation by stakeholders in the planning process, lack of robust, transparent and accountable implementation strategies, inadequacy of qualified staff and lack of 'holistic approach' to the planning process. Taking these findings into account, an improved buffer zone land-use planning framework is suggested. For the framework to enhance both conservation and development and to enable policies and legislation, equitable benefit sharing and conservation education, initiation of compensation schemes for depredation caused by wild animals and intensification of patrols are required.     

Ecosystem services–A tool for sustainable management of human–environment systems. Case study Finnish Forest Lapland

The concept of ecosystem services (ESs) is a relatively new scientific methodology, offering a possible approach to the prevention of ecological problems caused by human action and to the resolution of conflicts arising from land-use questions. Since ESs were launched as a major conceptual tool in the Millennium Ecosystem Assessment (MA, 2005), interest in them has been increasing. Despite the scientific as well as economic and political enthusiasm for the ES approach, only few case studies have as yet been published. We studied the interface between ESs and landscape planning in Forest Lapland, in northern Finland. In the article, we present a methodology and various databases which can be used in applied research on ESs. We classify the ESs offered by various biotopes of the study area, and examine the effects of different land-use forms on the provision of ESs. On the basis of our results, we suggest possible uses of the European CORINE land cover database in case studies.     

基于LUCC的生态系统服务空间化研究——以张掖市甘州区为例

生态系统服务(ES)评价为减缓或阻止人类活动导致的各种复杂生态问题提供了一种可能的方法,同时也有助于解决日益增加的各种土地利用冲突.以张掖市甘州区为例,运用一种新的空间化方法开展生态系统服务研究,并注重实现与土地利用研究的集成分析.首先根据研究区不同的群落生境和土地利用类型划分生态系统服务类型,然后检验不同土地利用类型和方式对各类生态系统服务供给的影响,最后分析该方法和数据的不确定性.结果表明:1)在灌区和甘州区两个尺度上,4类ES生产能力值均表现为:文化服务＞支持服务＞调节服务＞供给服务;2)2000-2009年,4类ES供给都呈递减趋势,同时,城镇用地、路网建设等人类活动驱动的土地利用方式迅速增加,整个绿洲农业区处于过度开发状态;3)该方法可操作性强,多学科的数据和知识分析是ES研究的难点.     

三峡库区典型流域聚落变迁的土地利用效应

三峡库区是典型的移民区和生态敏感区,探究其由于聚落变迁所引发的土地利用转移效应对于区域社会经济发展和生态恢复具有重要意义。以库区腹地草堂溪流域为研究对象,基于2000—2018年GOOGLE EARTH高分影像,结合当地自然地理环境和社会经济发展从微观尺度对山区聚落变迁的土地利用效应进行剖析。研究表明:(1)扩张型聚落周边以耕地转为果园为主;衰退型聚落周边土地利用转型主要表现为耕地向果园、有林地转变;自然增长型聚落周边以耕地和灌木林地向有林地,果园转化;消没型聚落周边以耕地,果园转为林草地,撂荒地为主,经济和生态效益均有所提高;且除消没型聚落外,另外3种聚落类型周边土地利用功能逐渐向生产生态功能转变,消没型周边土地利用功能逐渐侧重于生态功能。(2)2000—2010年,聚落变迁劳动力转移是聚落周边用地类型变化的根本因素,政府政策是是造成土地利用转型的直接因素;2010—2018年社会经济发展是土地利用转型的直接驱动因素,而农户生计需求是引发用地类型变化的根本驱动力;(3)聚落的变迁,不仅驱动了土地利用转型而且促使流域内经营主体由农户个体经营向政府、企业为主的经营主体转变。研究结果对于库区生态建设,农户经济发展以及改善人居环境等方面具有一定的积级作用。     

基于土地利用冲突识别的国家公园社区调控研究——以钱江源国家公园为例

功能分区和土地利用冲突识别为国家公园社区调控提供空间指引,为社区精细化管理提供依据。以钱江源国家公园试点区（以下简称为"钱江源国家公园"）为例,综合考虑国家公园建设多重目标,建立了生态保育、游憩利用和农业生产适宜性评价体系,并基于三类适宜性构建潜在土地利用冲突识别矩阵。通过叠加国家公园功能分区与土地利用冲突分析结果,识别国家公园社区类型并提出调控措施。结果表明：①三类适宜性土地利用总量较丰富且存在空间差异,其中生态保育适宜性呈中部高,南北两侧低的分布特征,游憩利用、农业生产适宜性呈中部、北部高,南部低的空间特征;②土地利用冲突识别矩阵将钱江源国家公园土地利用冲突划分为4大类,即用地优势区、冲突激烈区、冲突一般区和冲突微弱区,其中47.24%的土地存在潜在利用冲突,冲突等级以冲突激烈为主,用地优势区占比50.21%;③基于国家公园功能分区框架与土地利用冲突结果叠加分析,将国家公园社区划分为区外安置型、控制发展型、优先整治型、游憩发展型、特色农业型5种类型,并提出差异化调控措施。     

Intensity of Land Use in the Catchment Influences Ecosystem Functioning Along a Freshwater-Marine Continuum

Intensification of catchment land use often adversely affects ecosystem health in rivers and estuaries via changes to physicochemistry and ecosystem functioning, but whether such land-use effects differ along a freshwater-marine continuum has not been studied. We investigated relationships between intensity of land use and two measures of ecosystem function in freshwater, estuarine and near-marine habitats. Standardized bioassays to determine cellulose breakdown (cotton and canvas strips) and algal accrual rates (ceramic tiles) were deployed in 10 river-to-marine continua whose catchment areas ranged from 2.6 to 99.6% developed. Using general linear models and an information-theoretic approach to select the best predictive models for our response variables, we found that higher dissolved phosphorus concentrations, linked with highly developed catchments, were associated with greater rates of cellulose decomposition (both tensile strength loss and mass loss). Furthermore, after controlling for the contribution of phosphorus or salinity, decomposition rates in freshwater and near-marine habitats generally responded curvilinearly to catchment development, indicating the involvement of additional unmeasured, land-use-related physicochemical or biological variables. The strength and shape of relationships between percentage developed land area and algal biomass accrual rates also contrasted among freshwater (strongest, curvilinear), mid-estuary (intermediate, positive), and near-marine sites (weakest, no obvious shape). Because land-use intensity can influence ecosystem functioning along the entire continuum from streams and rivers to estuaries and coasts, resource managers should adopt an integrated approach to decisions affecting catchment land use.     

Land use policies and their effects on Brazilian farming production

For decades Brazil has faced a dilemma based on a perceived dichotomy between natural preservation and economic progress. Since 1988, more than 446,000 km² of native land has been cleared by clearcutting in Brazilian Legal Amazon alone, an area comparable to Sweden. In addition to the biodiversity loss associated with this activity, it is a significant global warming source since more than 72% of gross CO_2e emissions of Brazil come from land use, land-use change, forestry, and agriculture. As such, the national commitment to reduce greenhouse gas emissions by 37% by 2025 and 43% by 2030, with respect to 2005 levels, is likely to be at risk. Here, a simulation model has been created to provide decision-makers with knowledge about the future of Brazilian farming production in deforestation, neutral net land-use change, and reforestation scenarios. It has been found that farming demand and capital supply impact farming production significantly more than land availability. If reforestation policies to 2005 natural coverage levels were to be implemented, there would be no significant differences in Brazilian major farming crop production to a reference scenario of continuous deforestation. However, this would be at the expense of secondary crops usually earmarked for the domestic market. For Brazil to preserve its natural coverage, it must also inevitably improve crop productivity, especially in the Northeast region, while also being cognizant of the impact on domestic food prices. Lastly, Brazil needs to have incentives to foster intensive livestock farming. These results provide evidence that can support policies towards the profitable and sustainable scenarios described in the simulations.     

Degradation and loss of forest land and land-use changes in Sarawak,East Malaysia: a study of native land use by the Iban

Swidden agriculture, commercial logging and plantation development have been considered to be the primary common causes of degradation and loss of tropical rain forests in Southeast Asia. In this paper, I chose a part of northeastern Sarawak, East Malaysia as my case study area to analyze the changes in its land-use characteristics. In the study area, as well as primeval forests, we see that land use began about 100 years ago by a native group called the Iban; commercial logging began in the 1960s, and the development of oil palm plantations began recently. I describe the changes in land use as well as their social and economic causes by referring to aerial photographs, literature surveys, interviews with government officers and the Iban, and observation of land use. My analysis of land use demonstrates that on “state land”, where commercial logging and oil palm plantation development are occurring, large areas of forest have been disturbed in a short period of time. The objective is to benefit economically in response to the social and economic conditions surrounding the study area. On the other hand, in the “Iban territory,” where the Iban practice their land use, land conversion has not occurred on a large scale and in a short period of time, even though the forest has been cut and agricultural fields have been created in response to social and economic conditions as well. They disperse small agricultural fields throughout their forest land. Therefore, the landscape of the “Iban territory” is based on secondary forest, composed of patches of forest in various stages and with several types of agricultural land. Today in Sarawak, monocrop plantations are rapidly expanding and little primeval forest remains. Given these conditions, the land-use practices of natives such as the Iban will be evaluated from the viewpoint of ecosystem and biodiversity conservation. It could play an important role in providing habitats for natural wildlife.     

建设用地减量化的苏锡常地区土地利用格局优化——基于白鹭生境网络优化视角

建设用地减量化管理国家战略的本质就是土地利用格局优化,具有重要理论价值和实践意义。以建设用地减量化为背景、快速城市化苏锡常地区为研究区,采用目标物种白鹭生境网络优化为减量化依据的方法,旨在回答"建设用地怎么减?减哪里?减多少?依据是什么?"的土地利用格局优化问题。结果表明:1)白鹭核心生境斑块距离人为干扰源较远,需减量化的建设用地数量较少,但多数核心生境斑块面积小于平均值,破碎化现象较严重;白鹭迁移廊道受人为干扰严重,需减量化的建设用地数量为6542.1 hm~2,占减量化总面积的99%以上;生态核心区经过耕地占补平衡后,城乡建设用地二次减量213.7 hm~2、新增水田208.7 hm~2;研究区建设用地减量化总面积6755.8 hm~2。2)通过增加核心生境斑块面积、提高迁移廊道通达安全性,白鹭生境网络优化了。同时完成了建设用地总量减量化,实现了区域土地利用格局优化的目的。     

Bioenergy crops,biodiversity and ecosystem services in temperate agricultural landscapes—A review of synergies and trade-offs

The Paris agreement on climate change requires rapid reductions in greenhouse gas emissions. One important mitigation strategy, at least in the intermediate future, is the substitution of fossil fuels with bioenergy. However, using agriculture- and forest-derived biomass for energy has sparked controversy regarding both the climate mitigation potential and conflicts with biodiversity conservation. The urgency of the climate crisis calls for using forests for carbon sequestration and storage rather than for bioenergy, making agricultural biomass an attractive alternative for fossil energy substitution. However, this calls for comprehensive assessments of its sustainability in terms of consequences for biodiversity and ecosystem services. In this review, we provide a first holistic overview of the impacts on ecosystems of land-use changes from bioenergy crop production in temperate climates, by synthesizing results on both biodiversity and ecosystem service impacts. We found that bioenergy-related land-use changes can have both positive and negative effects on ecosystems, with original land use, bioenergy crop type and scale of bioenergy production being important moderators of impacts. Despite the risk of opportunity cost for food production, perennial crop cultivation on arable land had the lowest occurrence of negative impacts on biodiversity and ecosystem services. Growing biomass for bioenergy on surplus land has been suggested as a way to alleviate competition with food production and biodiversity conservation, but our results demonstrate that utilizing marginal or abandoned land for bioenergy crop production cannot fully resolve these trade-offs. Furthermore, there is a lack of empirical studies of the biodiversity value of marginal and abandoned land, limiting our understanding of the sustainability implications of biomass cultivation on surplus land. We argue that future research and policies for bioenergy production must explicitly consider biodiversity and ecosystem services in combination to avoid potential trade-offs between the two and to ensure sustainable bioenergy production.     

Identifying the contradiction between the cultivated land fragmentation and the construction land expansion from the perspective of urban-rural differences

Land use contradictions and conflicts between arable and construction land areas have long been major topics in the field of land use research. However, few studies have explored the impact of differences in development between urban and rural areas on the amount and landscape level of arable land. In this study, two decades of data were combined to classify the Yangtze River Delta mega-city cluster area, where urbanization has been evident in China, into urban and rural areas. Based on this, we analyzed the differences in the changes in the amount of arable land caused by the expansion of urban and rural construction land. In this study, a comprehensive framework of arable land fragmentation indicators was constructed and the geographically weighted regression model was introduced to detect spatial and temporal dynamic change patterns of arable land fragmentation caused by different urbanization processes in urban and rural areas. The results show the following: (a) The expansion of urban and rural construction land caused arable land loss, and both contributed non-negligibly to arable land loss. (b) The distribution of the arable land fragmentation index showed obvious spatial heterogeneity, and its low-value area corresponded to a lower level of urban/rural construction land development. However, its high-value area did not show a stable dependence on the level of urban/rural construction land development. (c) Changes in urban and rural built-up land were the driving factors for changes in the degree of arable land fragmentation. In general, the expansion of the urban fringe increased the fragmentation of arable land, and the intensive expansion of urban centers curbed the fragmentation of arable land. However, rural construction land exhibited a stronger and more widespread impact than urban areas as a whole. This study contributes new ideas for arable land conservation policies under the growing mechanization of agriculture, especially in areas with large differences in development between urban and rural areas. Additionally, it emphasizes the need for rational planning of construction land in rural areas. The results of this study can provide references for urban-rural development planning, rural revitalization, and implementation of arable land protection.     

2005-2015年四川省土地利用变化及驱动力分析

以2005、2010、2015年三期四川省土地利用栅格数据为基础,应用ENVI和GIS技术对数据进行预处理,采用土地利用转移矩阵与土地利用动态度模型,并结合四川省土地利用实际情况分析四川省2005-2015年土地利用变化特征,并利用SPSS软件对2005-2015年间统计年鉴上相关的社会经济数据进行因子分析,研究影响四川省土地利用变化的主要驱动力因素并分析其作用机理,为后来的四川省土地利用规划提供参考依据。结果表明：(1)四川省近10年土地利用类型面积变化较为频繁,表现为城乡居民工矿用地大幅度增加,但各类土地占比总量土地面积变化不大。(2)耕地、林地、草地始终为四川省的主要土地利用类型,占比较为均衡且保持性好,耕地处于25%左右,林地和草地始终处于35%左右。而城乡居民工矿用地、水域以及未利用地面积虽有变化但占比始终较小。(3)四川省土地利用存在明显的区域差异,东部土地利用程度高,西部利用程度低。林地和草地大量且长期集中在西部,城乡居民工矿用地则在东部集中,东西分布极不均衡,不利于四川省区域经济均衡发展。(4)影响四川省土地利用变化的主要驱动力因子为常驻人口数和GDP,常驻人口始终保持较大数额且稳步增长,保持劳动力人口数量的同时带来社会经济快速发展的结果,从而促使土地利用结构不断发生变化。     

典型喀斯特地区石漠化景观格局对土地利用变化的响应

土地利用是人类活动最基本的表现形式,探讨石漠化与土地利用变化之间的响应关系,对于石漠化治理和区域的可持续发展是非常重要的。基于贵州道真县2005年、2015年LANDSAT和石漠化数据,再利用ENVI 5.3进行监督分类,将道真县土地利用分为8种类型。通过景观格局空间分析技术和3S技术,对道真县土地利用时空演变和石漠化景观格局进行综合分析,结果表明:(1) 2005—2015年间,道真县建设用地和灌木林地面积增加,大部分灌木林地由水田和旱地转化而来,其面积增加了7.51%,建设用地增加了1.30%。(2)近10年间,研究区石漠化等级间的转移表现为轻、中、重度转化为潜在石漠化,其斑块转移面积分别为11.26、38.79、2.71 km2,表明研究区石漠化景观得到了恢复,低等级石漠化斑块面积增加,降低了原有高等级石漠化斑块的优势度。(3) 2005—2015年间道真县土地利用和石漠化景观格局,多样性指数分别下降了0.6434和2.4309,均匀度指数各减少了0.0552和0.5436,分维度指数各提高了0.0061和0.0801,蔓延度指数各增加0.1751、25.5396和聚合度指数分别增加1.8688和2.9112,景观形状指数分别减少0.9812和4.536,石漠化景观格局的变化对应土地利用景观格局指数的变化,随着人们土地利用方式的改变,石漠化也发生相应的改变。通过该研究的进行,有助于提高人们对石漠化和土地利用景观格局的认识,基于景观生态学背景对石漠化治理成效进行评估,为之后的石漠化治理工作的进行及研究提供了参考。     

Adoption of Policy Incentives and Land Use: Lessons From Frontier Agriculture in Southeastern Peru

Literature on environmental change often highlights the importance of public policies as a key driver of land use and land cover change. However, demonstration of policy impacts in agricultural settings has been hampered by the lack of systematic analysis across landholders, who may not universally adopt government policy incentives, or time periods, which may be associated with differing policy regimes. This paper evaluates the importance of voluntary adoption of policy incentives offered by Peruvian government administrations over two decades for land-use among small farmers in the Peruvian Amazon. The analysis focuses on whether farmers adopted one or more policy incentives in order to observe the effects on land uses including mature forest, agricultural crops, cattle pasture, and secondary growth. We employ multivariate statistical models to estimate the effects of policy adoption while controlling for other factors. The findings show that distinct policies are associated with particular land-uses and largely follow expectations. Specifying policy incentives promulgated by governments and differentiating among adopters and non-adopters advances understanding of the impacts of public policies on land use.     

福建省安溪县土地利用时空演变规律及其关键驱动因素

以福建省安溪县为研究边界,选取了1999—2019年该县及所属乡镇的耕地、林地、草地、园地、水域、建设用地和未利用地等7个土地利用类型作为物种变量,与其相关性较大的社会经济指标为环境变量,采用典范对应分析和空间自相关等方法进行分析,以明确安溪县和所属乡镇的土地利用时空演变特征及其关键驱动因素。研究结果表明:安溪县1999—2019年间土地利用类型变化总体上呈"三减四增"态势,并在全局空间分布格局上呈明显的聚焦状态。全县耕地、草地和水域面积分别减少36.82%、22.91%和8.18%,而林地、园地(主要是茶园)、建设用地和未利用地面积则分别增加了10.37%、56.39%、206.08%和90.14%。就林地面积而言,近10年来安溪县24个乡镇中有1/3的乡镇林地呈下降趋势。其中,祥华、大坪、虎邱、参内、福田和城厢6个乡镇林地面积减少明显。研究表明:在县域水平上,主要土地利用类型变化,除了受地理因素的制约外,主要受社会经济指标和宏观政策的驱动因素调控。排位最大的前3个因素分别是社会消费品零售总额、地区生产总值和茶叶产量。在镇域水平上,不同乡镇由于地理条件,特别是城镇化水平和经济发展状况...     

Development of a spatially explicit approach for mapping ecosystem services in the Brazilian Savanna – MapES

The objective of the presented study is the development of a spatially explicit approach for mapping ecosystem services (MapES) by using specific knowledge about the Cerrado biome (Brazilian Savanna). This biome covers an area of about 2 million km², i.e. nearly 24% of the total area of Brazil, and has come under substantial pressure during the last 50 years caused by strong land-use/land-cover change, mostly due to agricultural expansion and urbanization. Because of its fast transformation rate, there is an enormous demand for knowledge, and its application, about the effects of land-use/land-cover on the capacity of providing or maintaining ecosystem services. The MapES approach was developed using a vast existing knowledge base. After analyzing and structuring this knowledge the relationships between land-use/land-cover and the potential to provide or maintain eight ecosystem services (Erosion Control, Runoff Control, Water Supply, Water Quality Maintenance, Soil Quality Maintenance, Biodiversity Maintenance, Food Production and Energy Production) were parametrized. In addition, the approach was developed as spatially explicit by including landscape properties (soil, slope and distance to river network) in the cell based system. A reference map of potential natural vegetation and a land use map for 2013 for a meso-scale experimental catchment (32.7 km²) were produced. The catchment was used as an example to apply the approach, i.e. assessing and visualizing changes from before human interference to the current land use situation. Finally, a procedure for assessing the potential impacts of land-use/land-cover on ecosystem services considering the methodological limitations of the respective monitoring. The presented approach is easy to understand, to modify and to adapt to other situations and might be therefore used in other context of decision support. It might also help to fill the gap between land use planning and numeric modeling using very complex tools.     

Multiscale Characterization of Land-Use Patterns in China

This article explores the pattern of land use in China to understand the relationships between land use and factors that can be used to predict it. Such understanding is important for development of comprehensive models of land-use dynamics. Correlation and regression analyses are used to identify the most important explanatory variables from a large set of factors generally considered important in predicting the distribution of land use. We found that the spatial distribution of all land-use types in China is best described by an integrated set of biophysical and socioeconomic factors. Specific attention is given to the influence of the scale of analysis on study results. Both data resolution and the extent of the study area influence the discovered relationships. Relationships obtained at a certain scale of analysis therefore may not be directly applied at other scales or in other areas. The relevance of the systematic and quantitative characterization of the land-use patterns in China for the parameterization of spatially explicit land-use models is discussed. Received 20 July 1999; accepted 10 March 2000.     

Bridging the gaps between agricultural policy, land-use and biodiversity

The fate of biodiversity is intimately linked to agricultural development. Policy reform is an important driver of changes in agricultural land-use, but there is considerable spatial variation in response to policy and its potential impact on biodiversity. We review the links between policy, land-use and biodiversity and advocate a more integrated approach. Ecologists need to recognize that wildlife-friendly farming is not the only land-use strategy that can be used to conserve biodiversity and to research alternative options such as land sparing. There is also a need for social scientists and ecologists to bring their approaches together, so that land-use change and its consequences can be investigated in a more holistic way.     

京津冀地区新型城镇化对土地生态效率影响的实证分析

近年来, 城市化进程的不断推进对城市土地利用及生态环境产生了极大影响。选取城镇化发展最为迅速与典型的京津冀地区作为研究区域, 采用超效率DEA模型及Malmquist效率指数, 从经济学角度分析2006-2015年土地生态效率的时空演变, 随后, 基于人口、富裕和技术(STRIPAT)模型, 构建新型城镇化发展水平的综合指标评价体系, 分析新型城镇化对土地生态效率的影响。研究结果表明: 京津冀地区城镇化发展水平与土地生态效率之间存在显著的正相关关系, 即城镇化水平的不断提升对土地生态效率的提高具有积极作用, 各城市土地生态效率在新型城镇化发展背景下存在明显的空间差异, 此外, 土地利用与管理技术水平的提高、环境政策的改变等均会对土地生态效率的提升产生积极影响。这项研究旨在为提高城市土地管理水平, 推动城市可持续发展提供决策支持。     

Bush encroachment under three contrasting land-use practices in a mesic South African savanna

This study determined the effects of land-use practice had on the rate and extent of bush encroachment in a mesic savanna in KwaZulu-Natal, South Africa. Changes in woody cover were measured for 1 km² sites in areas under communal, commercial and conservation land-use systems for the period between 1937 and 2000. Land users from each area were interviewed to gain the histories of each area and to determine how the changes in woody cover had impacted them and whether anything was being done to counteract the spread of trees and shrubs on their land. Bush encroachment occurred across all three of the land-use types in the 67-year period between 1937 and 2000. The results showed that land-use practice had enormous impacts on the process of bush encroachment. The communal site showed a decrease in grass (21%) and tree (5%) cover and an increase in shrub cover (13%). At the commercial site, there was a considerable decrease in grass cover (46%) and moderate increase in shrub cover (10%) and a massive increase in tree cover (36%). The area under conservation showed a substantial decrease in grass cover (47%), a slight decrease in shrub cover (19%) and a massive increase in tree cover (66%). The perceived causes of these changes were fairly similar amongst the different land users. The changes were mostly not perceived to be a problem for the communal land users. The main advantages mentioned were increased woody resources for building and firewood and increased browse availability. The commercial and conservation land users perceived the changes to have significant negative connotations including the loss of grazing land and biodiversity and secondary invasion of encroached areas by alien plant species. Despite these perceptions, very little has been done to combat bush encroachment in the commercial and conservation land use systems.