Driving forces on the landscape require regional management and/or local actions, together with other external factors. To operationalize this approach, this paper carried out a comparative analysis of the naturalness dynamics of the Jacaré-Gua çu and Jacaré-Pepira watershed, based on land use/cover changes and a structural indicator of the landscape, over the 10-year (2004-2014), as support opportunities for improving its environmental planning and management. Land use/cover dynamics were obtained based on screen digitizing of LandSat imagery, using polygon manual digitalization. Naturalness scenarios of the watersheds, over the 10-year (2004-2014), were obtained based on Urbanity Indicator, which evaluates how much the natural landscapes are dominated by altered systems. The total area of watersheds showed a predominantly scenario, induced by anthropogenic agricultural and non-agricultural expansion areas, mainly by conversion of other land use/cover types in sugarcane cultivation. Despite the increase in natural vegetation areas, over the 10-year (2004-2014), Jacaré-Gua çu and Jacaré-Pepira watersheds are far from a sustainable condition. However Jacaré-Gua çu watershed presents a scenario of more committed naturalness due to the increase in Urbanity Index values ≥ 0.7. The historical process of land use occupation for agricultural production remains the main driving force of naturalness changes, occupying more than 70% of the total area of watersheds. These results have significant implications for fast urbanizing municipalities in providing key information about long term land use impact on the watershed structure and function, making it possible for policy makers, scientists and stakeholders to identify land uses which are hindered or enhanced under various scenarios of land use change over the time, and making it possible to explore the trade-offs between them to improve watershed management.
The conversion of natural landscapes into cultural landscapes has been transforming a significant part of earth’s surface. Human modification in land use/cover appeared as unprecedented in global scale in the last fifty years [
Land use/cover is one of the most important drivers of change that directly affects biodiversity in understanding the interactions between human activities and the environment [
This process is quite common in developing countries, where land use/cover changes resulting from socio-economic development have caused serious environmental problems such as landscape fragmentation and loss of naturalness [
Land conversion took place through increasing agriculture and urbanization affect, significantly energy flows, biogeochemical cycles, biodiversity and climatic conditions at local and/or regional scales [
Structural indicators of the landscape are fundamental to understand the risks and threats of land use/cover concerning land use sustainability, resulting in quantifiable information that reflects environmental and natural resources conditions, and their relations with anthropogenic activities [
Studies aimed at the characterization and diagnosis of landscapes under influence from the impact of land use/cover changes [
In this study, a comparative analysis of the naturalness dynamics of the Jacaré-Guaçu and Jacaré-Pepira watersheds was carried out, based on dynamics of land use/cover changes and a structural indicator of the landscape, over the 10 years (2004-2014), as support opportunities for improvement its environmental management. Specifically, the study attempted to discover if: 1) Naturalness showed a significant difference into and between the Jacaré-Guaçu and Jacaré-Pepira watersheds due to the spatial and temporal land use/cover changes over the 10 years (2004-2014); 2) The structural indicator of the landscape was efficient in identifying naturalness changes in the Jacaré-Guaçu and Jacaré-Pepira watersheds as a result of the spatial and temporal land use/cover changes.
The total area of study covers an extension of 683,150 ha, equivalent to the amount areas of the Jacaré-Guaçu and Jacaré-Pepira watersheds with areas of 416,800 ha and 266,350 ha, respectively. The study area is located between 21˚37’/22˚31’ south latitude and 47˚43’/49˚02’ west longitude, encompassing around 58% of the Tiete-Jacaré watershed’s area (UGRHI 13). The total study area covers 22 municipalities of the eastern-central region of São Paulo state, of which only sixteen of their urban perimeters can be found on the watershed limits (
Four protected areas are within the Jacaré-Guaçu and Jacaré-Pepira watershed limits: two Integral Protection areas (Itirapina Ecological Station with 2300 ha and Mata do Jacaré Ecological Station with 7 5 ha); and two Sustainable Use areas (Environmental Protection Areas of Corumbataí-Botucatu-Tejupá and of Ibitinga with 214,706.70 and 64,900 ha, respectively) (
The Jacaré-Guaçu River, with a 155 km long, begins between the São Carlos and Itirapina municipalities, while the Jacaré-Pepira River, with 174 km long, begins between the Brotas and São Pedro municipalities. The Jacaré-Guaçu and Jacaré-Pepira river mouth areas known as “Pantaninho” and “Varjão”, respectively, comprise a wetland system (
The UGRH1 13 region (
Economic activities are related to sugarcane and citrus cultivation, extensive areas for pasture and reforestation of Pinus sp. and Eucalyptus sp. The industrial sector is related to citrus fruits and sugar cane processing, as well as paper, beverages, footwear, and textiles. Some municipalities have natural scenic features that provide ecotourism activities [
Land use/cover dynamic were obtained based on screen digitizing of LandSat imagery, with 30 m spatial resolution, and a multispectral composite of three bands: near infrared, red and green wavelengths, over the 10-year period (2004-2014). The LandSat 5/TM and LandSat 8/OLI images, path 220 and 221, raw 75 and 76, were obtained on August 21 and 30, 2004 and August 1 and September 11, 2014, respectively. Image processing and georeferencing were carried out using ArcMap 10.2 software [
The land use/cover typology was discriminated by tone, texture and context criterias [
The consequences that land use changes have had on landscape naturalness were analyzed based on the Urbanity Index (UI) [
The UI [
UI = log 10 [ A + U F + W ] (1)
where A denotes agricultural area, U urban area, F natural vegetation area, and W aquatic environments and wetland area.
The spatial representation of the Urbanity Index was obtained through the commands Vector, Raster, Area and Image calculator in the IdrisiSelva software [
The permutational multivariate analysis of variance (PERMANOVA) [
The watershed’s landscape pattern, over a 10-year period (2004-2014), is determined by the presence of four land use classes (
The territorial limit of watersheds represents a human space occupation resulting from developmental actions in the natural landscape. Agricultural and
forestry sectors act as main drivers of change concerning watersheds [
Natural land use in Jacaré-Guaçu and Jacaré-Pepira watersheds’ total area, over the 10-year period (2004-2014), showed a minimal increase in change, equivalent to 173,075 and 91,654 ha, respectively, mainly due to the reduction of agricultural activities (
Farming practices act as the main drivers of change as anthropogenic agricultural land use comprises over 70% of both watersheds total area. Anthropogenic agricultural land use was reduced around 1% compared to the Jacaré-Guaçu and Jacaré-Pepira watersheds (
Continuous cropping and forestry land cover reduced from 10.03% to 5.72% and 6.91% to 6.62%, respectively, while bare soil increased by 22.96% to 31.80%. The increase in the total area of bare soil, equivalent to 60,388.76 ha, could be associated with the sugarcane harvest, which occurs between April and October in the state of São Paulo, as well as sugar cane expansion to produce ethanol [
The rate of land use change is increasing supporting biofuel feedstock production. In Brazil, sugarcane expansion is displacing degraded pastures, besides to impact soil physical quality due intensive mechanization [
Non-agricultural anthropogenic land use increased by 3,357.13 and 669.57 ha in the Jacaré-Guaçu and Jacaré-Pepira watersheds’ total area, respectively (
The aquatic environment showed an increase of 0.22%, equivalent to 886.13 ha, of Jacaré-Guaçu watershed total area, and a decrease of 0.15%, equivalent to 378.93 ha, of Jacaré-Pepira watershed total area (
High temperatures, even in autumn 2014 and a shortage of rainfall induced rapid evaporation of soil moisture. During the dry season, a lack of rainfall and the water demand for public supply, together with high water transpiration in the soil and absorption of minimum reserves by the vegetation, caused a reduction in the water sources level. However, in the study area, the natural vegetation and the extent of flooded area did not change, showing a dependence of water that supplies the availability reservoir. The natural vegetation surrounding the Jacaré-Guaçu and Jacaré-Pepira wetland areas, known as “Pantanal Paulista”, can use part of the stored water in the dry season, preventing water evaporation. However, when there are extreme cases of a lack of water, the vegetation competes with reservoirs in the water reserve.
Naturalness landscape refers to the natural capital stock which provides ecosystem services [
The UI values for the total area of both watersheds (
Lower UI values (UI ≤ 0.3) showed that around 15% of the total area of watersheds are related to higher naturalness, while higher UI values (UI ≥ 0.7) showed that around 10% of the total area of watersheds are related to lower naturalness over the 10-year period (2004-2014) (
The naturalness condition between both watersheds showed a significant difference in 2004 (F = 13.462, ρ = 0.002), but were not statistically different in 2014 (F = 0.2587, ρ = 0.624) (Figures 4(c)-(f)). The Jacaré-Guaçu watershed showed greater impairment of naturalness with a higher extent of critical naturalness area (UI ≥ 0.7), and a lower extent of high naturalness area (UI ≤ 0.3), 8.57% and 11.92%, respectively, when compared to the Jacaré-Pepira watershed (6.25% and 15.43%, respectively) in 2004 (
The Jacaré-Guaçu watershed showed no significant difference in the UI values (F = 2.8266, ρ = 0.106) from 2004 to 2014 (
The Jacaré-Pepira watershed showed a significant difference in the UI values (F = 6.9579, ρ = 0.012) from 2004 to 2014 with a higher naturalness commitment in 2014 due to the increase in the occupied area for classes of UI values higher than 0.3 and lower than 0.7 (
The Urbanity Index values for the total area of the watersheds, which corroborate with the spatial distribution of biodiversity conservation scenarios, showed a significant increase in natural vegetation areas over the 10-year period (2004-2014). This could be associated to a recovery of natural land use/cover and a reduction in the fragmentation of the natural vegetation process. This is particularly for municipalities that have land use/cover rules in their territorial limits to ensure the preservation of natural vegetation areas.
Despite the increase in natural vegetation areas, the sustainability conditions are not ensured for both watersheds due to the historical process of regional land use/cover by adopting non-sustainable practices. The result is a natural capital deficit framework currently below the minimum of carrying capacity necessary to ensure the stock of natural capital and ecosystem services for human welfare and economic development, mainly for the Jacaré-Guaçu watershed which shows a more critical situation due to natural capital loss.
This scenario makes it essential to know the amount of the remaining natural capital in both watersheds area, as well as the implementation of strategies to control or minimize the loss of habitat and local biodiversity. The question is what amount of natural capital should be remain under current trends and policies given trade-offs with economic development and agriculture. According a review carried out by [
Thus, the threshold of 30% could be considered as the lower natural capital limit for a landscape managed by man to balance economic use and biodiversity conservation [
Anthropogenic agricultural and non-agricultural land use/cover were the main driving forces considering the naturalness of the Jacaré-Guaçu and Jacaré-Pepira watersheds over the 10-year period (2004-2014) as a result of the regional economic development and population growth demands by resources and the remaining natural habitats. This anthropogenic pressure exerted on both watersheds, and it is essential to apply land use sustainability strategies for the conservation of the most representative forest remnants and native vegetation. These strategies comply the need of instruments that facilitate the integration of planning and monitoring of biodiversity in areas of outstanding environmental value, like wetlands and the four protected areas located within the Jacaré-Guaçu and Jacaré-Pepira watershed limits.
We conclude by considering that dynamics of land use/cover still acting from before 2004, as the main driver for Jacaré-Guaçu and Jacaré-Pepira watersheds to undergoing a quick transition from natural to cultural landscape. A more accurate scenario shows that both watersheds are currently threatened by unsustainable land use related to a quick anthropic occupation. This trend changes ecological sustainability, reducing the ecosystem’s resilience, as well as ecosystem services provided by the different land use/cover that summarizes the most relevant economic and environmental issues of the territorial municipalities.
Naturalness scenarios in both watersheds showed spatial displacement, over the 10-year period (2004-2014), due to the fragmentation of natural vegetation induced by agricultural and non-agricultural anthropogenic land use/cover. The Jacaré-Guaçu watershed showed a higher impairment of the naturalness condition in 2004 compared to the Jacaré-Pepira watershed, resulting from the anthropic occupation over the 10-year period (2004-2014). This naturalness watersheds impairment comes from a time previous to 2004, without evidence of change in this trend.
These results have significant implications for the fast urbanizing municipalities in providing key information about long term land use impact on the watershed structure and function, making it possible for policy makers, scientists and stakeholders to identify, at a glance, land uses which are hindered or enhanced under various scenarios of land use change over the 10-year period, and making it possible to explore the trade-offs between them to improve watershed management.
Therefore, implementing ecological and economic zoning in the Jacaré-Guaçu and Jacaré-Pepira watersheds is essential to ensure the protection and conservation of water resources and ecological life-support systems, particularly in the municipalities that are located in their surroundings. This zoning would require the maintenance of sustainable land use to improve the well-being of the local population, looking for a balance between socio-economic development and environmental conservation.
Financial support was provided by the Coordination for the Improvement of Higher Education Personnel (CAPES) and the São Paulo Research Foundation (FAPESP).
Costa, R.T., Gon- çalves, C.F., Fushita, A.T. and dos Santos, J.E. (2017) Land Use/Cover and Naturalness Changes for Watershed Environmental Management (Southeastern Brazil). Journal of Geoscience and Environment Protection, 5, 1-14. https://doi.org/10.4236/gep.2017.511001