Land change in the southern Yucatán: case studies in land change science

The southern Yucatán Peninsular Region project was designed from the outset as an integrative, multidisciplinary program of study examining tropical deforestation in the largest track of seasonal tropical forest remaining in Mexico and in which smallholder agriculture and a major biosphere reserve are juxtaposed in regard to land uses and covers. Treating land as a coupled human–environment system, the project joins the remote sensing, environmental, social, and modeling sciences in a way that is now recognized as land change science. This paper introduces the project, the study region, and six papers that explore some of the coupled system dynamics in the region. These include the sub-regional variation in deforestation, the pan-regional adoption or anticipation of cattle ranching, the emergence of divergent household agricultural and overall livelihood strategies, the roles of cultural and household histories in agricultural livelihood choices, the temporal intensification of swidden cultivation and its implications for forest species, and carbon stocks across cultivation units, including a new econometric modeling application to forecast changes in these stocks.     

Indicators of deforestation in the Southern Brazilian Pre-Amazon

In recent years, Amazonian deforestation has become a question of global concern. Deforestation in Amazon is a complex phenomenon in nature and has been related to traditional agriculture expansion. In this work, land use, socioeconomic and conservation indicators, combined with statistical analysis, were used to understand forces associated with patterns of deforestation. This approach was applied in Southern Brazilian Pre-Amazon in Mato Grosso State, which represents an extensive rain forest-savanna ecotone, located in the south border of Amazon biome. Based on data from the last two agricultural censuses (1995/1996–2006), we compared agricultural expansion in this area and Mato Grosso state. Results have shown that 85 % of state deforestation was concentrated in Southern Pre-Amazon and was closely related to increase in number of cattle and pasture area. PCA results pointed that population (92 %), number of cattle (86.5 %), pastures (84.2 %) and tractors (78.4 %) were variables with highest positive correlation to deforestation. It showed that GDP contributes to an individual axis and has a low correlation to deforestation (37.8 %). Conservation units and indigenous reserves also contribute to a single axis and were negatively correlated to temporary crops area. Results revealed a significant reduction in production and commercialization of extractive products in the region, revealing that the main, almost only conservation policy in Mato Grosso remains the creation of Special Areas. We suggest that further studies are necessary to screen development alternatives to simple cutting trees down. It is important to diversify strategies for deforestation control, and development aspects must be more seriously considered to reach a sustainable deforestation control policy.     

Brazil’s Amazonian forest carbon: the key to Southern Amazonia’s significance for global climate

Southern Amazonia is the first region of Brazil’s Amazon area to be exposed to intensive conversion to agriculture and ranching. This conversion emits greenhouse gases from the carbon stock in the biomass and soils of the previous vegetation. Quantifying these carbon stocks is the first step in quantifying the impact on global warming from this conversion. This review is limited to information on Brazilian Amazonia’s carbon stocks. It indicates large amounts of carbon at risk of emission in both biomass and soils, as well as considerable uncertainty in estimates. Reducing uncertainty is a priority for research but the existence of uncertainty must not be used as an excuse for delaying measures to contain deforestation. The magnitude of carbon stocks is proportional to greenhouse gas emissions per hectare of deforestation and consequently to impact on global climate.

     

Combining remote sensing and household level data for regional scale analysis of land cover change in the Brazilian Amazon

Land cover change in the Brazilian Amazon depends on the spatial variability of political, socioeconomic and biophysical factors, as well as on the land use history and its actors. A regional scale analysis was made in Rondônia State to identify possible differences in land cover change connected to spatial policies of land occupation, size and year of establishment of properties, accessibility measures and soil fertility. The analysis was made based on remote sensing data and household level data gathered with a questionnaire. Both types of analyses indicate that the highest level of total deforestation is found inside agrarian projects, especially in those established more than 20 years ago. Even though deforestation rates are similar inside and outside official settlements, inside agrarian projects forest depletion can exceed 50% at the property level within 10–14 years after establishment. The data indicate that both small-scale and medium to large-scale farmers contribute to deforestation processes in Rondônia State encouraged by spatial policies of land occupation, which provide better accessibility to forest fringes where soil fertility and forest resources are important determinants of location choice.     

Modelling land use change across elevation gradients in district Swat, Pakistan

District Swat is part of the high mountain Hindu-Kush Himalayan region of Pakistan. Documentation and analysis of land use change in this region is challenging due to very disparate accounts of the state of forest resources and limited accessible data. Such analysis is, however, important due to concerns over the degradation of forest land leading to deterioration of the protection of water catchments and exposure of highly erodible soils. Furthermore, the area is identified as hotspot for biodiversity loss. The aim of this paper is to identify geophysical and geographical factors related to land use change and model how these relationships vary across the district. For three selected zones across the elevation gradient of the district, we analyse land use change by studying land use maps for the years 1968, 1990 and 2007. In the high-altitude zone, the forest area decreased by 30.5 %, a third of which was caused by agricultural expansion. In the mid-elevation zone, agriculture expanded by 70.3 % and forests decreased by 49.7 %. In the lower altitudes, agriculture expansion was 129.9 % consuming 31.7 % of the forest area over the forty-year time period. Annual deforestation rates observed were 0.80, 1.28 and 1.86 % in high, mid and low altitudes, respectively. In the high-altitude ecosystems, accessibility (distance to nearest road and city) had no significant role in agriculture expansion; rather land use change appears significantly related to geophysical factors such as slope, aspect and altitude. In the low-elevation zone, accessibility was the factor showing the closest association with agriculture expansion and abandonment. The analysis illustrates that land use change processes vary quite considerably between different altitudinal and vegetation cover zones of the same district and that environmental constraints and stage of economic development provide important contextual information.     

Land cover changes in the Lachuá region,Guatemala: patterns,proximate causes,and underlying driving forces over the last 50 years

Identifying the patterns of land cover change (LCC) and their main proximate causes and underlying driving forces in tropical rainforests is an urgent task for designing adequate management and conservation policies. The Lachuá region maintains the largest lowland rainforest remnant in Guatemala, but it has been highly deforested and fragmented during the last decades. This is the first paper to describe the patterns of LCC and the associated political and socioeconomic factors in the region over the last 50 years. We estimated spatial and temporal variations in LCC from a random sample of 24 1-km² landscape plots during three time periods (1962–1987, 1987–2006, and 2006–2011) and evaluated how they were related to some important proximate causes and underlying driving forces. During the study period, 55 % of forest cover disappeared, at an annual rate of 1.6 %. The deforestation rate increased from 0.6 % (during the first study period) to 2.8 % (last period), but there was very high spatial variation. Landscape plots located outside conservation areas and close to roads lost between 80 and 100 % of forest cover, whereas the forest cover in landscapes located within protected areas remained intact during the study period. The establishment of new human settlements, roads, and annual crops was the main proximate cause during the first period, but during the second and third periods, open areas were mainly created to establish cattle pastures. Because ~75 % of forest cover has disappeared outside the protected areas, the conservation of this biodiversity hot spot will depend on the expansion of protected areas, and the promotion of forest regrowth and alternative biodiversity-friendly land uses in the landscape matrix.     

Development of a land-use forecast tool for future water resources assessment: case study for the Mekong River 3S Sub-basins

Land-use change is one of the major factors that alter local and regional hydrology. For areas experiencing fast expansion of urban and agriculture areas, land-use changes often adversely affect stream flow and water resources at the local and watershed scale. The Sekong, Sesan, and Srepok (3S) Sub-basins are a part of the Lower Mekong River Basin and include land in Cambodia, Lao People’s Democratic Republic (Laos), and Viet Nam. The region is experiencing a dynamic land-use transition because of rapid changes in its economy, society, and environment. Major land-use changes include deforestation of native rain forest, expansion of agricultural and urban areas, and expansion of commercial plantation such as rubber trees. These land-use alterations have affected local and regional hydrologic processes, resulting in stream flow shortages during the dry season and flash flooding due to deforestation. In this research, deforestation in the 3S Sub-basins over the period 1993–1997 was analyzed using multi-logistic regression. The regression analysis indicated that density of agricultural cells within a 5-km radius from each forest cell and slope strongly affected the deforestation process. A land-use forecast model to simulate deforestation and urbanization sites was developed in GIS based on local land-use change trends. The model was applied to 2003 land use to forecast 2033 land use and future water demand, which was further compared with present stream flow measurements during the dry season at various places in the region. The entire approach from the land-use forecast to its impact assessment on stream flow could help local stakeholders understand watershed-wide future water resources risks and develop future water resources plans. With the 3S Sub-basins being used as a case study area, this article presents a land-use forecast tool; simulated 2033 land-use and water demand; and the estimation of the impact of the forecasted future water demand on the local stream flow.     

Rainfall trends,land use change and adaptation in the Chaco salteño region of Argentina

Regional change under agricultural expansion in the Chaco of Argentina is determined by interactions of rainfall change, infrastructure development, socio-economic actions and values, and the social perceptions of change. Our study focused on adaptation in the socio-environmental system which is the key to understanding opportunities, uncertainties and risk in the context of historical change. Change in land use from extensive grazing through mixed farming and on to industrial-scale soybean production was made possible by a trend of increasing rainfall that reduced the risk of crop failure from drought since the 1970s. Rainfall change coincided with a period in which the Chaco forest was suffering extensive degradation from long-term extractive use. The degradation aided agricultural expansion since the degraded state of the ecosystem justified public policies of deforestation. In parallel to these resource-based processes, public policy changed in the late 70s and 80s toward favoring privatization of state land and exclusion of small producers. This permitted the land concentration needed for industrial-scale production. Technological innovation in both water and land resource management reinforced the process of concentration because small producers rarely have the financial or educational capital to develop or implement emerging technologies. One of the results of the intensification and expansion of agriculture is that soil surface sealing, waterlogging and flood risk are now effective at a landscape scale. To address these risks, private enterprise and government efforts must now come together toward innovative policies in integrated landscape management.     

Scenarios of land-use change in a deforestation corridor in the Brazilian Amazon: combining two scales of analysis

Local, regional, and global processes affect deforestation and land-use changes in the Brazilian Amazon. Characteristics are: direct conversions from forest to pasture; regional processes of indirect land-use change, described by the conversion of pastures to cropland, which increases the demand for pastures elsewhere; and teleconnections, fueled by the global demands for soybeans as animal fodder. We modeled land-use changes for two scenarios Trend and Sustainable Development for a hot spot of land-use change along the BR-163 highway in Mato Grosso and Pará, Brazil. We investigated the differences between a coupled modeling approach, which incorporates indirect land-use change processes, and a noncoupled land-use model. We coupled the regional-scale LandSHIFT model, defined for Mato Grosso and Pará, with a subregional model, alucR, covering a selected corridor along the BR-163. The results indicated distinct land-use scenario outcomes from the coupled modeling approach and the subregional model quantification. We found the highest deforestation estimates returned from the subregional quantification of the Trend scenario. This originated from the strong local dynamics of past deforestation and land-use changes. Land-use changes exceeded the demands estimated at regional scale. We observed the lowest deforestation estimates at the subregional quantification of the Sustainable Development story line. We highlight that model coupling increased the representation of scenario outcomes at fine resolution while providing consistency across scales. However, distinct local dynamics were explicitly captured at subregional scale. The scenario result pinpoints the importance of policies to aim at the cattle ranching sector, to increase land tenure registration and enforcement of environmental laws.

     

Forest land conversion dynamics: a case of Pakistan

The present research focuses on estimating forest area change with respect to the ongoing forest land conversion. The study tests the hypothesis that forest land is being converted to the selected land use categories with high growth tendency and controlling deforestation rate to its half of the present level would significantly improve the land cover under forest. The rate of forest land conversion to other land use categories is analyzed and then compared with the total area expanded under three land use classes. We used Systems dynamic modeling approach to estimate forest area by simulating forest land conversion in Pakistan, projecting to 2030. The results show that rangeland, built-up area and cultivated land have increased over time; growth rate of built-up area (9%) is highest followed by rangeland area (1.7%) and cultivated area (0.3%), respectively; rangeland is the dominant category in terms of area expanded (0.74 m. ha). Sensitivity analysis showed that reducing deforestation rate to half of the past level of 1% could not significantly improve forest area; therefore, it is suggested that controlling deforestation alone is not an effective strategy unless drastic measures, e.g., demarcation of forest boundaries, land use control policy and afforestation campaign would be started in the country.     

National and regional determinants of tropical deforestation in Colombia

Global tropical deforestation continues to occur at high rates despite political attention. National-level forest baselines are being established all over the world to guide the implementation of several policy mechanisms. However, identifying the direct and indirect drivers of deforestation and understanding the complexity of their interlinkages are often difficult. We first analyzed deforestation between 1990 and 2005 at the national level and found an annual deforestation rate of 0.62 %. Next, we performed separate analyses for four natural regions in Colombia and found annual deforestation rates between 0.42 and 1.92 %. Using general linear models, we identified several direct causes and underlying factors influencing deforestation at the national level: rural population density, cattle, protected areas, and slope. Significant differences in deforestation rates and causes were found across regions. In the Caribbean region, drivers of loss are urban population, unsatisfied basic needs, slope, and precipitation and four land use variables (illicit crops, pastures, cattle, and fires). In the Orinoco region, crops are the main driver of forest loss, and in the Amazonian region, deforestation is primarily due to fires related to the colonization front. Policy mechanisms will have to take into account regional patterns to successfully balance development and forest preservation in Colombia.     

Population dynamics,rural livelihoods and environmental degradation: some experiences from Tanzania

Population growth and environmental degradation are closely linked. Increasing population has in many rural areas of Tanzania contributed to changes in land use/cover patterns, land fragmentation and livelihood insecurity. Increasing demand for food, energy and other environmental services has contributed to expansion of agriculture, including marginal areas, and deforestation often leading to environmental degradation. Increased reliance on natural resources for rural livelihoods, subsistence nature of the agricultural sector and limited economic opportunities in rural areas are among the factors leading to rural–rural and rural–urban migrations searching for better livelihood opportunities. The high urban demand for food and biomass energy from rural areas has also contributed to rural deforestation and overall environmental degradation. This paper addresses the linkages between population and environmental degradation in Tanzania. It argues that effective implementation of development and resources management policies can lead to environmental sustainability even with growing populations. It provides evidence from successful land management interventions such as HADO, HASHI and SECAP, which support the argument that with effective implementation of resource management initiatives even larger populations can be supported by the available resources. Such successful interventions ought to be emulated elsewhere with similar environmental problems.     

Dependence on forest resources and tropical deforestation in Ghana

In Ghana, forests provide many products on which the local population subsists. However, these resources are depleting due to a variety of factors including agricultural expansion and over-exploitation of forest resources. This paper presents an analysis of the level of local dependence on forest resources and its implications for forest management in Ghana. The paper also outlines the causes of continuing deforestation in the studied region from the perspective of the local residents and discusses what role they could play in addressing the problem. The aim is to share more light on the current causes of deforestation and make suggestions for improved community-based forest management practices that could help to reduce deforestation. Primary data was collected through personal interviews and focus group discussions with 431 household heads randomly selected from three Forest Districts in Ghana. The survey showed that income from agriculture constituted 60% of the average total rural household income. Forest income provided 38% of total household income, and off-farm income 2%. The four most highly ranked causes of deforestation are poverty-driven agriculture, lack of alternative rural wage employment other than farming, household population levels, and conflict in traditional land practices. This shows a shift in the view of local people who in the past were quick to blame logging companies and government policies for deforestation. The majority of the respondents depended on wild animals like snail, bush meat, wild honey and wild and cultivated vegetables. Given the reasons for deforestation, much thought needs to go into agroforestry practices (e.g. snail farming, bee keeping, fish farming, and vegetable production) in efforts to reduce deforestation, which are currently less promoted. Readers should send their comments on this paper to: BhaskarNath@aol.com within 3 months of publication of this issue.     

Watershed prioritization for soil erosion mapping in the Lesser Himalayan Indian basin using PCA and WSA methods in conjunction with morphometric parameters and GIS-based approach

Environment, Development and Sustainability - Watersheds in the subtropical Himalayan basins are highly prone to land degradation due to deforestation, landslides, intensive agriculture, population...     

Assessing the sustainability of agriculture: a case of Mae Chaem Catchment, northern Thailand.

Sustainability is not a new concept but rather a prominent concept at the present time. Researchers have categorized sustainability indicators into economic, social, and ecological aspects. Sustainability of agriculture in the context of development efforts has to meet production efficiency, resilience of ecosystems, appropriate technology, maintenance of the environment, cultural diversity, and satisfaction of the basic needs. The research objective of this study is to determine the critical indicators of agricultural sustainability in the Mae Chaem Catchment, northern Thailand. In assessing sustainability, the authors applied the sustainability indicator analysis developed by FAO. The results of the study show that food sufficiency in the Wat Chan subcatchment is the most sustainable aspect of agriculture. The least sustainable facets of agriculture in the Wat Chan subcatchment are land holding size, land tenure, and water shortage. While expansion of agricultural land in the watershed area is not legally permitted, a practice of agroforestry is recommended. Insecure land tenure may result in reduced incentives to improve land productivity. Thus, official recognition of land ownership is required. As the problem of water shortage is most critical in the lower reaches, increased participation in the allocation scheme by downstream villagers should be encouraged. Finally, the construction of a small-scale water storage in the lower part of the catchment to increase water supply should be considered.     

Agricultural adjustment,population dynamics and forests redistribution in a subtropical watershed of NW Argentina

Patterns of land-use and land-cover change are usually grouped into one of two categories defined by the dominant trend: (1) deforestation resulting from expanding agriculture and (2) forest expansion, usually related to the abandonment of marginal lands. At regional scale, however, both processes can occur simultaneously even in the absence of net change. Given the focus on net change, such redistribution of agricultural and natural and seminatural lands has been generally overlooked. The interaction between agriculture modernization, human demography and complex topographic gradients of northwestern Argentina has resulted in processes of both forest recovery and deforestation, thus providing the opportunity to analyze patterns and driving forces of land-cover redistribution. We analyzed 20 years (1986–2006) of land-cover change in a subtropical watershed in relation to topographic and demographic variables. Although net forest change represented <1 %, forests redistribution affected 7 % of forest lands. There was a consistent geographic segregation of deforestation and forest recovery, with forests expanding over steep highlands and agriculture expanding over lowland irrigated areas. Population trends were not associated to forest expansion in lowlands but they explained 32 % of forest recovery in highlands. Highland forest expansion and lowland deforestation, respectively, imply conservation opportunities for humid montane forests and the environmental services they provide (e.g., watershed conservation) and threats for the conservation of dry forests and its biodiversity. Our study exemplifies the importance of land-use redistribution (rather than net change) with relevant environmental consequences at regional scale.     

浙江省土地利用格局时空变化及生态风险评价

基于1990~2015年浙江省6期的土地利用数据,分析土地利用的时空变化,构建生态风险指数,对不同时期的浙江省土地利用生态风险进行了评价。结果表明：（1）浙江省土地利用变化表现为耕地大量减少而建设用地剧增;土地利用转移方向主要为耕地、林地、水域向建设用地转移;其中以2000~20005年和2010~2015年土地利用动态度最高;（2）浙江省生态环境质量下降。中生态风险区是区域的主导类型,较高、高生态风险区向外扩张,高值区主要分布在杭州湾附近,沿海区域,杭州西南部、衢州和金华三市接壤区域。低等级生态风险区分布在相邻高等级生态风险区的周围,大致成圈层状向外扩散;（3）土地利用生态风险等级转换差异较大。生态风险转移主要是由低向高等级转换,且其生态风险等级年均转换速率呈上升趋势,生态风险转换主要发生在城市、沿海区域如杭州湾附近、温州、台州沿海等经济发展活跃的地区;（4）浙江省各地级市生态风险值时空分异较大。各市生态风险值主要呈上升趋势,宁波市生态风险变化最大,衢州市变化最小。空间分布上,杭州市生态风险值最高,远大于其他地级市,舟山市生态风险值最低。     

Function of Agricultural Land Use and Its Evolvement in Peri-urban Area: A Case Study of Beijing

Rapid urbanization in Beijing stimulates the urban land expansion and diminishes available agricultural land. Monofunctional agricultural land use can not meet the demand of the devel- opment of the multifunctional agriculture and urbanization any more, so multifunctional agricultural land use is going to be promoted in the city. This article proposes the evolvement of the land use change from 1992 to 2004 and discusses some evolvement views.