scholarly journals Multi-Scale Assessment of Relationships between Fragmentation of Riparian Forests and Biological Conditions in Streams

2019 ◽  
Vol 11 (18) ◽  
pp. 5060 ◽  
Author(s):  
Yirigui ◽  
Lee ◽  
Nejadhashemi

Due to anthropogenic activities within watersheds and riparian areas, stream water quality and ecological communities have been significantly affected by degradation of watershed and stream environments. One critical indicator of anthropogenic activities within watersheds and riparian areas is forest fragmentation, which has been directly linked to poor water quality and ecosystem health in streams. However, the true nature of the relationship between forest fragmentation and stream ecosystem health has not been fully elucidated due to its complex underlying mechanism. The purpose of this study was to examine the relationships of riparian fragmented forest with biological indicators including diatoms, macroinvertebrates, and fish. In addition, we investigated variations in these relationships over multiple riparian scales. Fragmentation metrics, including the number of forest patches (NP), proportion of riparian forest (PLAND), largest riparian forest patch ratio (LPI), and spatial proximity of riparian forest patches (DIVISION), were used to quantify the degree of fragmentation of riparian forests, and the trophic diatom index (TDI), benthic macroinvertebrates index (BMI), and fish assessment index (FAI) were used to represent the biological condition of diatoms, macroinvertebrates, and fish in streams. PLAND and LPI showed positive relationships with TDI, BMI, and FAI, whereas NP and DIVISION were negatively associated with biological indicators at multiple scales. Biological conditions in streams were clearly better when riparian forests were less fragmented. The relationships of NP and PLAND with biological indicators were stronger at a larger riparian scale, whereas relationships of LPI and DIVISION with biological indicators were weaker at a large scale. These results suggest that a much larger spatial range of riparian forests should be considered in forest management and restoration to enhance the biological condition of streams.

2019 ◽  
Vol 11 (10) ◽  
pp. 2870 ◽  
Author(s):  
Yirigui Yirigui ◽  
Sang-Woo Lee ◽  
A. Pouyan Nejadhashemi ◽  
Matthew R. Herman ◽  
Jong-Won Lee

Anthropogenic activities, such as land use and land cover modifications in riparian areas, can alter the degree of fragmentation of riparian vegetation, lead to the degradation of stream habitats, and affect biological communities in the streams. The characteristics of the riparian forests can modify the condition of stream environments and the transporting mechanisms of materials, sediments, nutrients, and pollutants loaded from the watersheds. This study aimed to examine the relationships between forest fragmentation and three biological indicators of trophic diatom, benthic macroinvertebrate, and the fish assessment in the Nakdong River, Korea. Eighty-nine biological assessment sampling sites in the National Aquatic Ecological Monitoring Program of South Korea were identified. For each sampling site, riparian forest data within a 500 m radius were extracted from national LULC using GIS to compute fragmentation metrics using FRAGSTATS software. Four fragmentation metrics—number of forest patches, percentage of riparian forest cover (PLAND), largest riparian forest patch index (LPI), and riparian forest division index (DIVISION)—were correlated with the biological indicators. Also, due to severe spatial autocorrelation among observations, the fragmentation metrics and stream environmental variables were regressed to biological indicators using regression tree analysis. Our results indicate that the biological indicators were significantly associated with most forest fragmentation metrics. We found positive correlations of PLAND and LPI with biological indicators, whereas DIVISION was negatively correlated with biological indicators. Both correlation and regression tree analyses revealed that the biological conditions of streams were likely to be better if riparian forests are less fragmented. Particularly, stronger relationships were revealed between macroinvertebrates and fish with the fragmentation metrics of riparian forests than with benthic diatoms. However, these relationships varied with elevation, stream size, and slope conditions. The results of this study reinforced the importance of including riparian forests in the planning, restoration, and management of stream environments. These results also suggested that planners and managers may need to consider different strategies for different stream environments and topographic characteristics in managing riparian forests.


2020 ◽  
Vol 13 (6) ◽  
pp. 3060
Author(s):  
Suelen Crispim Sutil ◽  
José Augusto Costa Gonçalves ◽  
Eliane Maria Vieira

A avaliação da fragilidade ambiental das bacias hidrográficas vem se tornando cada vez mais importante no cenário ambiental, devido ao desenvolvimento gradativo da sociedade e a expansão tecnológica e econômica ao longo dos anos. Uma estratégia adotada para amenizar a degradação e restabelecer o equilíbrio, é a formação de corredores ecológicos (CEs), que auxilia na ligação entre remanescentes naturais. A bacia do rio Piracicaba passa por um longo histórico de degradação e de fragmentação florestal, principalmente próximo às cidades devido ao desmatamento de matas ciliares. Em vista disso, este trabalho analisou e comparou a aplicação de dois diferentes modelos de fragilidade ambiental, aplicada a esta bacia e, a partir de seus produtos identificou a melhor metodologia base para a proposição de corredores ecológicos na região. Com os resultados obtidos, foi possível inferir que, além de grande parte da bacia apresentar grau de fragilidade entre fraco e médio, as áreas mais vulneráveis são aquelas mais próximas à cabeceira da bacia. O estabelecimento dos corredores ecológicos abrangeu, prioritariamente, as áreas de maior fragilidade entre a conexão dos fragmentos de vegetação e as Áreas de Preservação Permanentes (APPs), assim, verificou-se que é necessário o reflorestamento de cerca de 342,24 km² das APPs da bacia para que seja possível a conexão entre as remanescentes e 2,0 km²  de áreas de ligação. Comparative analysis of the environmental fragility of the Piracicaba river basin using two methodological models: support for the application and proposition of Biological Corridors A B S T R A C TThe assessment of a river basin’s environmental fragility has become even more important on the environmental scenery due to society’s gradual development and technological and economic expansion over the years. An adopted strategy to ease the degradation and restore the ecological balance is the establishment of biological corridors that can assist the connection between natural forest patches. The Piracicaba river basin has been going through a long history of degradation and forest fragmentation, especially near the cities because of the deforestation of riparian forests. Therefore, this paper analyzed and compared the application of two adapted environmental fragility models in this river basin and identified from their products the best base methodology for the proposition of ecological corridors. From the results, it was possible to infer that, in addition to a big part of the basin present poor and average fragility level, the most vulnerable areas are the ones close to the source of the main rivers. The biological corridors establishment covered, primarily, the most vulnerable areas between the fragments of remaining forests and the Permanent Preservation Areas (PPAs) and, from this, it was possible to verify that the reforestation of around 132,14 mi² of PPAs is necessary for the connection of patches of remaining forests and 0,77 mi² of connections areas.Keywords: environmental vulnerability, geoprocessing, environmental management.


2017 ◽  
Vol 68 (3) ◽  
pp. 519 ◽  
Author(s):  
A. E. Siegloch ◽  
R. Schmitt ◽  
M. Spies ◽  
M. Petrucio ◽  
M. I. M. Hernández

Riparian forests have positive effects on water quality and biodiversity. However, most studies have only tested the effects of distinct vegetation types or streams with and without forests, despite the fact that riparian forests differ in degrees of complexity. The aim of the present study was to test whether riparian forest complexity affected the composition and abundance of the Ephemeroptera, Plecoptera and Trichoptera (EPT) taxa across a small environmental gradient. We also measured whether EPT genera or feeding groups responded to changes in riparian forest complexity. The study was conducted in two protection areas (i.e. Lagoa do Peri Municipal Park, PERI; and the Permanent Protection Area of Ratones, RAT) of Santa Catarina Island, Brazil. Primary production increased in streams with lower canopy percentage, and EPT assemblages differed among streams with different riparian forest complexity. In RAT, the water quality and forest variables affected EPT composition; however, in PERI, only water quality variables were important. Indicator species analysis based on genera suggested Kempnyia (Plecoptera) and Zelusia (Ephemeroptera) to be indicative of streams with greater forest complexity, whereas Farrodes (Ephemeroptera) was significant in streams of intermediate riparian forest complexity; however, no one functional group dominated. The results of the present study show that small changes in riparian forest complexity influence the composition of EPT insects in subtropical streams.


2017 ◽  
Vol 2 (2) ◽  
pp. 124
Author(s):  
Soko MI ◽  
Gyedu-Ababio T

<em>Biological indicators such as macro-invertebrates and water quality parameters can give an overalln overview of what is happening in a river catchment. The aim of the study was to determine the influence of anthropogenic activities on macro-invertebrates assemblage and water quality using multivariate analysis and to determine the present ecological state of the river using the Macro-Invertebrates Response Assessment index. The South African Scoring System Version 5 (SASS 5) was used to collect macro invertebrates. Water quality samples were collected using a polyethylene bottle and analysed by Mpumamanzi Laboratory in Nelspruit and Water lab in Pretoria. From the results obtained it was evident that anthropogenic activities along the Crocodile River play a role in water quality deterioration and the subsequent distribution of macro-invertebrates during high and low flow conditions. The main anthropogenic activities contribute to the influence of macro-invertebrates community and water quality are agricultural activities in the upper reaches and a  combination of industrial, domestic, mining and agricultural activities in the middle and lower reaches of the Crocodile River.</em>


Author(s):  
Enzo Luigi Crisigiovanni ◽  
Elynton Alves do Nascimento ◽  
Rodrigo Felipe Bedim Godoy ◽  
Paulo Costa de Oliveira-Filho ◽  
Carlos Magno de Sousa Vidal ◽  
...  

 Considering the current importance watercourses quality conservation, it is important to establish relationships between parameters that enable evaluation of the origins of changes in water quality, allowing actions to mitigate them. However, it is important to improve the association of different variables and to take sufficient samples. This study associates usual techniques and parameters to analyse the water quality of an urban river from Paraná State, Brazil. For this, we used biological indicators (aquatic macroinvertebrates), physical-chemical (temperature, turbidity, true colour, pH, DO and BOD5,20) indicators and microbiological (faecal and total coliforms) indicators. These indicators were related to land use and occupation classes obtained from high resolution QuickBird 2 images. For this association, the surroundings (450 meters buffer) of three distinct points of the river were considered: I. Near the spring; II. In the downtown city; and III. In a residential neighbourhood. Different values of physical, chemical and microbiological variables were detected along the river, showing evident relationships between them and with the use and occupation of the urban and peri-urban space in the characterization of surface waters. The association design was able to detect the landscape effect on water quality in a coherent way and that these connections were mainly related to suppression of the riparian forest present in the surroundings, further demonstrating the importance of this vegetation for the maintenance of watercourse quality.


2010 ◽  
Vol 37 (3) ◽  
pp. 249 ◽  
Author(s):  
Cecilia Smith-Ramirez ◽  
Juan L. Celis-Diez ◽  
Erik von Jenstchyk ◽  
Jaime E. Jimenez ◽  
Juan J. Armesto

Context. Remnant forest patches in rural landscapes may be important sites for maintaining viable populations of restricted forest species, especially when these remnant habitats maintain some connectivity, for instance through riparian vegetation strips and other forest patches. Aims. We assessed the use of remnant forest habitats in a rural landscape of southern Chile (40°S) by the ‘near threatened’ arboreal marsupial Dromiciops gliroides (Microbiotheria), in relation to habitat type (riparian strips, forest fragments and continuous forests), width of the riparian forests, and the presence and abundance of the hemiparasite Tristerix corymbosus, whose fruits are readily eaten by D. gliroides. Methods. In two summers, 2004 and 2008, we set up grids of 96 live traps for three consecutive nights at each of 16 sites along two riparian forest strips, four additional sites in remnant, non-riparian forest patches, and four more within continuous pre-Andean forest. We counted hemiparasites on trees in the trapping grid area, and estimated their individual volumes. Key results . In total, 48 individuals of D. gliroides were captured at all sites during the 2 years. We documented a significant positive relationship between the width of riparian vegetation and the number of individuals captured (r s = 0.78, P = 0.02, n = 8) for one riparian strip, but not for the second one. Neither habitat type nor the frequency of hemiparasites related statistically to D. gliroides abundance. Key conclusions. We conclude that in the rural landscape of the Chilean Lake District, narrow riparian forest strips, in a highly inter-connected mosaic of remnant forest patches may be as important as large patches and continuous Andean forests to sustain viable populations of this threatened, strictly arboreal, marsupial. Implications. The present study reports, for the first time, the presence in narrow riparian forests immersed in a pasture-dominated agricultural matrix of this forest-specialist marsupial, which was previously known only from continuous pre-Andean forests.


2017 ◽  
Vol 68 (8) ◽  
pp. 1744-1748
Author(s):  
Catalina Stoica ◽  
Gabriela Geanina Vasile ◽  
Alina Banciu ◽  
Daniela Niculescu ◽  
Irina Lucaciu ◽  
...  

During the past few decades, the anthropogenic activities induced worldwide changes in the ecological systems, including the aquatic systems. This work analysed the contamination level of groundwater resources from a rural agglomeration (Central-Western part of Prahova County) by biological and physico-chemical approaches. The study was performed during the autumn of 2016 on several sampling sites (four drilling wells, depth higher than 100 m supplying three villages; two wells lower than 10 m depth and one spring). The water quality was evaluated by comparison with the limit values of the drinking water quality legislation (Law no.458/2002) and the Order 621/2014 (applicable to all groundwater bodies of Romania). The results showed that phenols and metals (iron and manganese) exceeded the threshold values in all sampling sites. Moreover, the anthropogenic factors including agriculture, use of fertilizers, manures, animal husbandry led to an increase of the bacterial load, particularly at wells sites.


2014 ◽  
Vol 49 (4) ◽  
pp. 372-385
Author(s):  
Shawn Burdett ◽  
Michael Hulley ◽  
Andy Smith

A hydrologic and water quality model is sought to establish an approach to land management decisions for a Canadian Army training base. Training areas are subjected to high levels of persistent activity creating unique land cover and land-use disturbances. Deforestation, complex road networks, off-road manoeuvres, and vehicle stream crossings are among major anthropogenic activities observed to affect these landscapes. Expanding, preserving and improving the quality of these areas to host training activities for future generations is critical to maintain operational effectiveness. Inclusive to this objective is minimizing resultant environmental degradation, principally in the form of hydrologic fluctuations, excess erosion, and sedimentation of aquatic environments. Application of the Soil Water Assessment Tool (SWAT) was assessed for its ability to simulate hydrologic and water quality conditions observed in military landscapes at 5th Canadian Division Support Base (5 CDSB) Gagetown, New Brunswick. Despite some limitations, this model adequately simulated three partial years of daily watershed outflow (NSE = 0.47–0.79, R2 = 0.50–0.88) and adequately predicted suspended sediment yields during the observation periods (%d = 6–47%) for one highly disturbed sub-watershed in Gagetown. Further development of this model may help guide decisions to develop or decommission training areas, guide land management practices and prioritize select landscape mitigation efforts.


2021 ◽  
Vol 13 (6) ◽  
pp. 3246
Author(s):  
Zoe Slattery ◽  
Richard Fenner

Building on the existing literature, this study examines whether specific drivers of forest fragmentation cause particular fragmentation characteristics, and how these characteristics can be linked to their effects on forest-dwelling species. This research uses Landsat remote imaging to examine the changing patterns of forests. It focuses on areas which have undergone a high level of a specific fragmentation driver, in particular either agricultural expansion or commodity-driven deforestation. Seven municipalities in the states of Rondônia and Mato Grosso in Brazil are selected as case study areas, as these states experienced a high level of commodity-driven deforestation and agricultural expansion respectively. Land cover maps of each municipality are created using the Geographical Information System software ArcGIS Spatial Analyst extension. The resulting categorical maps are input into Fragstats fragmentation software to calculate quantifiable fragmentation metrics for each municipality. To determine the effects that these characteristics are likely to cause, this study uses a literature review to determine how species traits affect their responses to forest fragmentation. Results indicate that, in areas that underwent agricultural expansion, the remaining forest patches became more complex in shape with longer edges and lost a large amount of core area. This negatively affects species which are either highly dispersive or specialist to core forest habitat. In areas that underwent commodity-driven deforestation, it was more likely that forest patches would become less aggregated and create disjunct core areas. This negatively affects smaller, sedentary animals which do not naturally travel long distances. This study is significant in that it links individual fragmentation drivers to their landscape characteristics, and in turn uses these to predict effects on species with particular traits. This information will prove useful for forest managers, particularly in the case study municipalities examined in this study, in deciding which species require further protection measures. The methodology could be applied to other drivers of forest fragmentation such as forest fires.


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