scholarly journals Impact of Urbanization on Large Wood Sizes and Associated Recruitment Zones

Hydrology ◽  
2020 ◽  
Vol 7 (4) ◽  
pp. 89
Author(s):  
Matthew T. Allen ◽  
Philippe G. Vidon
Keyword(s):  
Land Use ◽  
Agricultural Land ◽  
Urban Land Use ◽  
Agricultural Land Use ◽  
Large Wood ◽  
Legacy Effect ◽  
Impact Of Urbanization ◽  
Forest Land Cover ◽  
Developed World ◽  
Significant Opportunity

Although the presence of large wood (LW) has long been recognized to enhance watershed function, land use impact on LW remains poorly understood. Using a series of six watersheds, we investigate the relationships between LW recruitment zones, LW size, and LW jam occurrence and land use. Although the results in general show urban land use to severely limit LW, they also stress that agricultural land use may be positively correlated to LW. Occurrence of potentially productive LW recruitment zones is nevertheless best correlated to total forest land cover and forested riparian area. However, the lack of mature forest due to previous widespread deforestation linked to historical agricultural land use is likely a limiting legacy effect. Since the pattern of land use seen in the study area is typical of much of the developed world, our results suggest the limiting of LW may be a major way in which watersheds are impacted in many regions. Accordingly, reintroduction of LW represents a significant opportunity to restore watersheds on a broad scale. Specifically, we propose a mix of passive conservation and active restoration of LW sources and that the targeting of these tactics be planned using the spatial analysis methods of this study.

The Impact of Urbanization on Agricultural Land Use

2015 ◽  
Vol 2015 (3) ◽  
pp. 60-75
Author(s):  
Elena Belova ◽  
Yuliya Rozenfeld
Keyword(s):  
Land Use ◽  
Agricultural Production ◽  
Agricultural Land ◽  
Arable Land ◽  
Agricultural Land Use ◽  
Economic Relations ◽  
Long Time ◽  
The Subject ◽  
Impact Of Urbanization ◽  
The Impact

The subject of the study presented in this article is the economic relations arising due to the progress of the urbanization that leads to changes in agricultural production. For a long time in Russia a reduction of agricultural land, arable land and crops takes place. One reason for this is the global progress of urbanization. Changes in agricultural land use occur across the country however this process is uneven in different regions. Among all regions Moscow and Moscow region significantly stand out. The study showed that in the more urbanized regions of the country reduction of the agricultural land and changes in agricultural land use are greater than in less urbanized ones.

scholarly journals An Estimated Structural Equation Model to Assess the Effects of Land Use on Water Quality and Benthic Macroinvertebrates in Streams of the Nam-Han River System, South Korea

2020 ◽  
Vol 17 (6) ◽  
pp. 2116 ◽  
Author(s):  
Jong-Won Lee ◽  
Sang-Woo Lee ◽  
Kyung-Jin An ◽  
Soon-Jin Hwang ◽  
Nan-Young Kim
Keyword(s):  
Water Quality ◽  
Land Use ◽  
Structural Equation ◽  
Agricultural Land ◽  
Stream Water ◽  
Equation Model ◽  
Urban Land Use ◽  
Benthic Macroinvertebrate ◽  
Agricultural Land Use ◽  
Stream Water Quality

The extent of anthropogenic land use in watersheds determines the amount of pollutants discharged to streams. This indirectly and directly affects stream water quality and biological health. Most studies have therefore focused on ways to reduce non-point pollution sources to streams from the surrounding land use in watersheds. However, the mechanistic pathways between land use and the deterioration of stream water quality and biological assemblages remain unclear. This study estimated a structural equation model (SEM) representing the impact of agricultural and urban land use on water quality and the benthic macroinvertebrate index (BMI) using IBM AMOS in the Nam-Han river systems, South Korea. The estimated SEM showed that the percent of urban and agricultural land in the watersheds significantly affected both the water quality and the BMI of the streams. Specifically, a higher percent of urban land use had directly increased the biochemical oxygen demand (BOD) and total phosphorus (TP), and deteriorated the BMI of streams. Similarly, higher proportions of agricultural land use had also directly increased the BOD, total nitrogen (TN), and total phosphorus (TP) concentrations, and lowered the BMI of streams. In addition, it was observed that the percent of urban and agricultural land use had indirectly deteriorated the BMI through increased BOD. However, we were not able to observe any significant indirect effect of the percent of urban and agricultural land use through increased nutrients including TN and TP. These results indicate that increased urban and agricultural land use in the watersheds had directly and indirectly affected the physicochemical characteristics and benthic macroinvertebrate communities in streams. Our findings emphasize the need to develop more elaborate environmental management and restoration strategies to improve the water quality and biological status of streams.

scholarly journals Agroforestry Systems of the Tehuacán-Cuicatlán Valley: Land Use for Biocultural Diversity Conservation

Land ◽  
2019 ◽  
Vol 8 (2) ◽  
pp. 24
Author(s):  
Mariana Vallejo ◽  
M. Isabel Ramírez ◽  
Alejandro Reyes-González ◽  
Jairo López-Sánchez ◽  
Alejandro Casas
Keyword(s):  
Land Use ◽  
Agricultural Land ◽  
Agroforestry Systems ◽  
World Heritage Site ◽  
Biocultural Diversity ◽  
Semiarid Region ◽  
Agricultural Land Use ◽  
Visual Interpretation ◽  
Natural Ecosystems ◽  
Human Settlements

The Tehuacán-Cuicatlán Valley, Mexico, is the semiarid region with the richest biodiversity of North America and was recently recognized as a UNESCO's World Heritage site. Original agricultural practices remain to this day in agroforestry systems (AFS), which are expressions of high biocultural diversity. However, local people and researchers perceive a progressive decline both in natural ecosystems and AFS. To assess changes in location and extent of agricultural land use, we carried out a visual interpretation of very-high resolution imagery and field work, through which we identified AFS and conventional agricultural systems (CAS) from 1995 to 2003 and 2012. We analyzed five communities, representative of three main ecological and agricultural zones of the region. We assessed agricultural land use changes in relation to conspicuous landscape features (relief, rivers, roads, and human settlements). We found that natural ecosystems cover more than 85% of the territory in each community, and AFS represent 51% of all agricultural land. Establishment and permanence of agricultural lands were strongly influenced by gentle slopes and the existence of roads. Contrary to what we expected, we recorded agricultural areas being abandoned, thus favoring the regeneration of natural ecosystems, as well as a 9% increase of AFS over CAS. Agriculture is concentrated near human settlements. Most of the studied territories are meant to preserve natural ecosystems, and traditional AFS practices are being recovered for biocultural conservation.

scholarly journals Relating environmental variables with aquatic community structure in an agricultural/urban coldwater stream

2021 ◽  
Vol 10 (1) ◽  
Author(s):  
Daniel T. L. Myers ◽  
Richard R. Rediske ◽  
James N. McNair ◽  
Aaron D. Parker ◽  
E. Wendy Ogilvie
Keyword(s):  
Land Use ◽  
Environmental Variables ◽  
Fish Community ◽  
Agricultural Land ◽  
Urban Land ◽  
Urban Land Use ◽  
Aquatic Communities ◽  
Natural Stream ◽  
Longitudinal Gradients ◽  
Agricultural Areas

Abstract Background Urban areas are often built along large rivers and surrounded by agricultural land. This may lead to small tributary streams that have agricultural headwaters and urbanized lower reaches. Our study objectives assessed are as follows: (1) landscape, geomorphic, and water quality variables that best explained variation in aquatic communities and their integrity in a stream system following this agricultural-to-urban land use gradient; (2) ways this land use gradient caused aquatic communities to differ from what would be expected for an idealized natural stream or other longitudinal gradients; and (3) whether the impacts of this land use gradient on aquatic communities would grow larger in a downstream direction through the agricultural and urban developments. Our study area was an impaired coldwater stream in Michigan, USA. Results Many factors structured the biological communities along the agricultural-to-urban land use gradient. Instream woody debris had the strongest relationship with EPT (Ephemeroptera, Plecoptera, and Trichoptera) abundance and richness and were most common in the lower, urbanized watershed. Fine streambed substrate had the strongest relationship with Diptera taxa and surface air breather macroinvertebrates and was dominant in agricultural headwaters. Fish community assemblage was influenced largely by stream flow and temperature regimes, while poor fish community integrity in lower urban reaches could be impacted by geomorphology and episodic urban pollution events. Scraping macroinvertebrates were most abundant in deforested, first-order agricultural headwaters, while EPT macroinvertebrate richness was the highest downstream of agricultural areas within the urban zone that had extensive forest buffers. Conclusion Environmental variables and aquatic communities would often not conform with what we would expect from an idealized natural stream. EPT richness improved downstream of agricultural areas. This shows promise for the recovery of aquatic systems using well-planned management in watersheds with this agricultural-to-urban land use pattern. Small patches of forest can be the key to conserving aquatic biodiversity in urbanized landscapes. These findings are valuable to an international audience of researchers and water resource managers who study stream systems following this common agricultural-to-urban land use gradient, the ecological communities of which may not conform with what is generally known about land use impacts to streams.

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