Rapid Assessment of Habitat Diversity Along the Araras Stream, Brazil
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Floresta e Ambiente 2018; 25(1): e20160024 http://dx.doi.org/10.1590/2179-8087.002416 ISSN 2179-8087 (online) Original Article Conservation of Nature Rapid Assessment of Habitat Diversity Along the Araras Stream, Brazil Adriel Barboza Bentos1, Anderson de Souza Gallo1, Nathalia de França Guimarães1, Maicon Douglas Bispo de Souza1, Rubismar Stolf2, Maria Teresa Mendes Ribeiro Borges3 1Programa de Pós-graduação em Agroecologia e Desenvolvimento Rural, Universidade Federal de São Carlos – UFSCar, Araras/SP, Brazil 2Departamento de Recursos Naturais e Proteção Ambiental, Universidade Federal de São Carlos – UFSCar, Araras/SP, Brazil 3Departamento de Tecnologia Agroindustrial e Sócio-Economia Rural, Universidade Federal de São Carlos – UFSCar, Araras/SP, Brazil ABSTRACT Agriculture, urbanization, and industrialization are some of the anthropogenic activities that constantly generate negative impacts on natural environments. Part of this degradation directly affects aquatic systems. This study aimed to evaluate the visual characteristics of the Araras Stream, located in the municipality of Araras, São Paulo state, Brazil. Data was collected at six different assessment sites along the river in both rural and urban areas. The evaluation used a Rapid Habitat Diversity Assessment (RHDA) protocol composed of 22 parameters, which define levels of preservation of ecological conditions. According to this protocol, the 32 Km-long study transect along the Araras Stream was rated as impacted (39.6 points). A separate assessment by transects showed that only Transect 1 presented a natural level of preservation (71.8 points). Transects located in the urban area contributed the most to impacts on the aquatic environment. The RHDA protocol proved to be an important tool to evaluate and monitor aquatic environments. Keywords: aquatic ecosystems, riparian vegetation, anthropogenic activities. 1. INTRODUCTION Aquatic ecosystems and the history of water on planet In the context of aquatic systems, a watershed Earth are multifaceted. The close relationship between is a geographic region bounded by water dividers, pollution levels and population density is determined encompassing the whole catchment area of a waterway. by three main factors: urbanization, industrialization, It is a natural geographic unit and its boundaries are and large-scale agriculture. Population growth with its established by the flow of water on the surface over consequent urbanization and increase in agricultural time. It is, therefore, the result of the interaction of areas, reduces the water retention capacity of river water with other natural resources (Rocha, 1991). basins and the natural capacity to retain pollutants. The micro basin of the Araras Stream is located in In view of the complexity of water use by humans, the central part of the municipality of Araras, Sao Paulo aquatic ecosystems are the most affected by environmental state, Brazil, and is a good example of anthropogenic pollution. Loss of water quality and availability has actions. The water quality of this stream is affected been observed in several regions and countries due by different processes of land use and occupation. to degradation (Tundisi, 2003). In addition to mining, deforestation, and pesticide 2/10 Bentos AB, Gallo AS, Guimarães NF, Souza MDB, Stolf R, Borges MTMR Floresta e Ambiente 2018; 25(1): e20160024 use in agricultural areas, intense urban and industrial capital city. It has a population of 118,000 inhabitants occupation is observed throughout the basin, which distributed as follows: 6% in the rural area and 94% in pollutes the stream (Projeto Ecoagri, 2006). the urban area (IBGE, 2010). Godoi (2008) highlighted the great importance of The regional relief is represented by low rolling hills characterizing and controlling water quality. In urbanized of sub-plain tops, whose slopes reach 5% on the sides regions, this control is an essential condition for the and 3% at the top. Towards the north, the topography evolution and development of populations, either is more undulating, with slopes of up to 20%. On the from a socioeconomic perspective or to obtain and flood plains flat areas or depressions with slope <2% are maintain quality of life. In rural areas, the importance generally found. Dystrophic Red Latosol (Oxisol) is of monitoring water quality mainly concerns the predominant in the region; these are strongly acid, conservation of ecosystems and the quality of ancient soils at an advanced stage of weathering, with agricultural activities. As a result, methods for rapid low base saturation (Resende et al., 2007; Santos, 2006). qualitative assessment have been developed to describe Climate in the region is Cwa according to Köppen the holistic quality of the physical habitat of aquatic classification, mesothermal, with hot summers, and dry ecosystems (Hannaford et al., 1997). These methods winters with mean lowest and highest temperatures of integrate a set of variables representative of the main 18 °C and 22 °C, respectively. The dry season is from components that determine the ecological processes April to September, with total rainfall in the driest of river systems (Callisto et al., 2002; Rodrigues & month <30 mm. Most rainfall occurs in January or Castro, 2008). February (Magini & Chagas, 2003). In this sense, the Rapid Habitat Diversity Assessment The Araras Stream micro basin is composed of (RHDA) protocols are introduced, given that they other streams that flow west to east-northeast, and has are methodological tools used to evaluate the levels its boundaries within the municipality (IBGE 1:50.000, of conservation of environmental conditions in river Folha Araras-SF23YAII). The micro basin covers an transects. Therefore, these protocols take into acount area of approximately 400 Km2, being the main source the integrated analysis of lotic ecosystems based on of the Tambury Dam, which provides 15% of the water the reading of easily understood and quickly applied supply of the municipality and, according to Magini parameters. Therefore, RHDA protocols are an & Chagas (2003), presents a dendritic pattern similar important tool in environmental monitoring programs to tree branches. (Callisto et al., 2001, 2002; Rodrigues et al., 2008). The purpose of the present study was to evaluate 2.2. Field procedures and data analysis the environmental degradation processes in rural The choice of the studied transects was based on and urban areas in the longitudinal gradient of the the criteria of ease of access and spatial distribution. Araras Stream watershed by means of qualitative and Thus these transects were established upstream from the quantitative visual analyses using the RHDA protocol. longitudinal gradient of Araras Stream comprising rural Aiming to contribute to measures that mitigate ecological (Transects 1, 2, and 6) and urban (Transects 3, 4, and 5) degradation, this study is expected to identify which areas, according to the mosaic shown in Figure 1. stream transects had the greatest negative impact on The extension analyzed included a longitudinal the aquatic environment. gradient of approximately 32 Km and, as presented in Table 1, some basic characteristics observed are listed 2. MATERIAL AND METHODS for each sampled transect. 2.1. Characterization of the study area The visual analysis was conducted according to the RHDA protocol. This protocol developed by Callisto et al. The municipality of Araras is located in the southeast (2002) is composed of two parts: the first part, adapted region of Sao Paulo state, Brazil. It occupies an area from the Ohio Environmental Protection Agency, USA of 644.8 Km2 within the 22º21’25”S; 47º23’03”W (EPA, 1987), seeks to evaluate the characteristics of geographic coordinates, distant 152 Km from the state the transect and the environmental impacts caused Floresta e Ambiente 2018; 25(1): e20160024 Rapid Assessment of Habitat Diversity Along… 3/10 Figure 1. Mosaic of the municipality of Araras and the six transects established for microbiology evaluation along the Araras Stream. Municipality of Araras, São Paulo state, Brazil. Table 1. Primary characteristics observed at the studied transects (geographic coordinates, altitude, soil use and occupation in the surrounding environment). Municipality of Araras, São Paulo state, Brazil. Sampled Geographic Characteristics of Soil use and occupation in the Altitude transects coordinates transects surrounding environment Preserved riparian vegetation, but 22º19’00.45”S 1 655 masl Near the source. surrounded by areas cultivated with 47º26’29.64”W sugarcane. Água Bruta - Tambury Lift Station. 22º20’12.49”S 2 631 masl Santa Lúcia Dam. Legal reserve of planted eucalyptus 47º24’32.10”W on one of the banks. Reforested riparian forest. One of 22º20’31.56”S Beginning of the urban 3 620 masl the banks with vegetation less than 47º23’46.41”W area. 30 m wide. 22º21’16.54”S Before the junction 4 607 masl Channeled area. 47º22’12.89”W with Furnas Stream. 22º21’28.32”S Together with the 5 606 masl Channeled area. 47º22’58.61”W Furnas Stream. Grassland. Depleted riparian 22º20’57.85”S Viaduct over the 6 601 masl vegetation, intense occupation with 47º20’45.46”W railway (rural area). Leucaena leucocephala Caption: masl = meters above sea level. by anthropogenic activities (Table 2); the second part, the sum of the values assigned to each parameter adapted from Hannaford et al. (1997), determines the independently. The extreme values for the scoring of parameters to assess the habitat and conservation levels the