Effects of Urban Sprawl on Forest Conservation in a Metropolitan Water Source Area

Abstract

The clearing of native vegetation in water source areas and its effects on water supply availability have become a major concern in large metropolises. This study examined the spatial and temporal changes in land use and cover and their effects on the conservation of Atlantic Forest in a water source area in the Metropolitan Region of São Paulo that is the second most densely populated territory in Brazil, the municipality of Diadema. Historical maps and trend scenarios were developed by applying the Markov chain in association with cellular automata. Forest conservation was assessed based on a set of landscape metrics of resource availability, fragment isolation, and trends of forest fragmentation. Our findings revealed an increase in urban growth of 37% in the last five decades directly associated to the clearing of 50% of forests in intermediate/advanced stages and 40% in early stages. The main drivers of landscape change were human-modified fields (41%) and net roads (54%). Optimal resource availability was drastically reduced (75%) while isolation increased (361.5%) among existing forest fragments. Therefore, future trends indicate that, without changes in the management of the area, deforestation may occur rapidly and continuously until 10% of forest remains, leading to potential adverse effects on water availability and quality of the Billings Reservoir and the local biodiversity.

Relationship between forest integrity, drainage headboards and patch-level metrics as subsidy for planning and conservation in fragmented Atlantic Forest areas

“…This law (Brasil, 2012b) prevents land use for agricultural production and urban expansion on the banks of watercourses and within a radius of 50 m around springs, which are directly related to the drainage headboards addressed in this study. This legislation is supported by scientific evidence (Dessie & Bredemeier, 2013;Goss et al 2014;Romero et al 2018, Mello et al 2020, and authors such as Galvani et al (2020) emphasized AREA that in some instances, legal protection is consequent conservation management influence the conservation of forest fragments more than patch-level or landscape metrics, such as AREA and, in this case, SHAPE.…”

“…Dessie and Bredemeier (2013) studied forested and pasture springs in the Philippine, and obtained that riparian vegetation in the upstream region of the watershed is essential to promote better water quality and quantity, reduce the sediment load and turbidity, and regulate the flow, avoiding flooding in the downstream areas. Romero et al (2018) studied urbanization's effects on forests in a watershed in a metropolitan region, obtaining that urban expansion and highways represent the most significant impacts on forest fragmentation and degradation, affecting negatively the availability and quality of water for supply. Therefore, in addition to the amount of DH (and possibly springs), the forest fragmentation recorded in Boituva, it must be also affecting negatively the quality and quantity of water in the watershed and the presence of aquatic fauna.…”

“…Native forests are closely related to soil conservation and consequently, agricultural production (FAO, 2020), human water supply, and other uses (Romero et al 2018, FAO, 2020. In addition, to minimize the effects of climate change (Scarano & Ceotto, 2015) and to provide species for human use (Brockerhoff et al 2017, Joly et al 2019.…”

Is There an Equivalence between Measures of Landscape Structural and Functional Connectivity for Plants in Conservation Assessments of the Cerrado?

“…The analysis of the landscape structure was performed using a set of metrics usually applied in the studies of landscape ecology for biological conservation [35,[39][40][41] (Table 1, Equations ( 1)-( 6)). Forest patches were assessed for their Optimal Resource Availability (ORA), calculated in ArcGIS ® (extension V-Late) using information on shape (Fsh), their size coefficients (CS), and the physiognomic importance of the forest patches (CF), an adaptation of the literature [39,42] with the inclusion of CF.…”

Reforest or perish: ecosystem services provided by riparian vegetation to improve water quality in an urban reservoir (São Paulo, Brazil)

“…Although the vegetation cover with exotic species (reforestation) is not in compliance with the current legislation for RPAs, we included this type of cover since the ecosystem functions and services for water regulation are somewhat similar to native forests (BROCKERHOFF et al, 2013;FERRAZ et al, 2013). Moreover, the presence of old commercial planting with the regeneration of native vegetation in the understory is a common structure for the reservoirs of SPMR (ROMERO et al, 2018). Even so, we cannot ignore concerns about the potential effects of forestry activities on water quality or the economic implications of limiting some chemical substances reaching lakes and streams (ERIKSSON et al, 2011).…”