scholarly journals Treeline advance - driving processes and adverse factors

2007 ◽  
Vol 1 ◽  
pp. 1-33 ◽  
Author(s):  
Friedrich Karl Holtmeier ◽  
Gabriele E. Broll
Keyword(s):  
Experimental Studies ◽  
Temporal Variations ◽  
Considerable Effect ◽  
Future Climate Change ◽  
Anthropogenic Factors ◽  
Site Conditions ◽  
Mature Trees ◽  
Climatic Regions ◽  
Functional Relationships ◽  
Animal Populations

The general trend of climatically-driven treeline advance is modified by regional, local and temporal variations. Treelines will not advance in a closed front parallel to the shift of any isotherm to higher elevations and more northern latitudes. The effects of varying topography on site conditions and the after-effects of historical disturbances by natural and anthropogenic factors may override the effects of slightly higher average temperatures. Moreover, the varying treeline-forming species respond in different ways to a changing climate. Forest advance upwards and northwards primarily depends on successful regeneration and survival of young growth rather than on increasing growth rates of mature trees. Every assessment of treeline response to future climate change must consider the effects of local site conditions and feedbacks of increasing tree population in modulating the climatically-driven change. Treeline-shift will influence regional and local climates, pedogenesis, plant communities, animal populations and biodiversity as well as having a considerable effect on economic changes in primary production. A better understanding of the functional relationships between the many treeline-relevant factors and treeline dynamics can be achieved only by extensive research at different scales within different climatic regions supported by as many as possible experimental studies in the field together with laboratory and remote sensing techniques.

The future of European floodplain wetlands under a changing climate

2011 ◽  
Vol 2 (2-3) ◽  
pp. 106-122 ◽  
Author(s):  
Christof Schneider ◽  
Martina Flörke ◽  
Gertjan Geerling ◽  
Harm Duel ◽  
Mateusz Grygoruk ◽  
...  
Keyword(s):  
Climate Change ◽  
Global Scale ◽  
Future Climate Change ◽  
Anthropogenic Factors ◽  
Climate Modelling ◽  
Floodplain Wetlands ◽  
Potential Threat ◽  
Climate Change Projections ◽  
The Future ◽  
Floodplain Inundation

In the future, climate change may severely alter flood patterns over large regional scales. Consequently, besides other anthropogenic factors, climate change represents a potential threat to river ecosystems. The aim of this study is to evaluate the effect of climate change on floodplain inundation for important floodplain wetlands in Europe and to place these results in an ecological context. This work is performed within the Water Scenarios for Europe and Neighbouring States (SCENES) project considering three different climate change projections for the 2050s. The global scale hydrological model WaterGAP is applied to simulate current and future river discharges that are then used to: (i) estimate bankfull flow conditions, (ii) determine three different inundation parameters, and (iii) evaluate the hydrological consequences and their relation to ecology. Results of this study indicate that in snow-affected catchments (e.g. in Central and Eastern Europe) inundation may appear earlier in the year. Duration and volume of inundation are expected to decrease. This will lead to a reduction in habitat for fish, vertebrates, water birds and floodplain-specific vegetation causing a loss in biodiversity, floodplain productivity and fish production. Contradictory results occur in Spain, France, Southern England and the Benelux countries. This reflects the uncertainties of current climate modelling for specific seasons.

scholarly journals Exploring the linkage between spontaneous grass cover biodiversity and soil degradation in two olive orchard microcatchments with contrasting environmental and management conditions

SOIL ◽  
2015 ◽  
Vol 1 (2) ◽  
pp. 651-664 ◽  
Author(s):  
E. V. Taguas ◽  
C. Arroyo ◽  
A. Lora ◽  
G. Guzmán ◽  
K. Vanderlinden ◽  
...  
Keyword(s):  
Soil Degradation ◽  
Control Measure ◽  
Diversity Indices ◽  
Temporal Variations ◽  
Site Conditions ◽  
Grass Cover ◽  
Biodiversity Indicators ◽  
Olive Orchard ◽  
Biodiversity Indices ◽  
Soil Losses

Abstract. Spontaneous grass covers are an inexpensive soil erosion control measure in olive orchards. Olive farmers allow grass to grow on sloping terrain to comply with the basic environmental standards derived from the Common Agricultural Policy (CAP, European Commission). However, to date there are few studies assessing the environmental quality considering such covers. In this study, we measured biodiversity indices for spontaneous grass cover in two olive orchards with contrasting site conditions and management regimes in order to evaluate the potential for biodiversity metrics to serve as an indicator of soil degradation. In addition, the differences and temporal variability of biodiversity indicators and their relationships with environmental factors such as soil type and properties, precipitation, topography and soil management were analysed. Different grass cover biodiversity indices were evaluated in two olive orchard catchments under conventional tillage and no tillage with grass cover, during 3 hydrological years (2011–2013). Seasonal samples of vegetal material and photographs in a permanent grid (4 samples ha−1) were taken to characterize the temporal variations of the number of species, frequency of life forms, diversity and modified Shannon and Pielou indices. Sorensen's index showed strong differences in species composition for the grass covers in the two olive orchard catchments, which are probably linked to the different site conditions. The catchment (CN) with the best site conditions (deeper soil and higher precipitation) and most intense management presented the highest biodiversity indices as well as the highest soil losses (over 10 t ha−1). In absolute terms, the diversity indices of vegetation were reasonably high for agricultural systems in both catchments, despite the fact that management activities usually severely limit the landscape and the variety of species. Finally, a significantly higher content of organic matter in the first 10 cm of soil was found in the catchment with worse site conditions in terms of water deficit, average annual soil losses of 2 t ha−1 and the least intense management. Therefore, the biodiversity indices considered in this study to evaluate spontaneous grass cover were not found to be suitable for describing the soil degradation in the study catchments.

scholarly journals A new method to quantify macroalgae and a practical sampler for experimentation in lotic habitats

2012 ◽  
Vol 72 (4) ◽  
pp. 853-857 ◽  
Author(s):  
AF. Tonetto ◽  
CK. Peres ◽  
CCZ. Branco
Keyword(s):  
Benthic Communities ◽  
Experimental Studies ◽  
Temporal Variations ◽  
Nondestructive Technique ◽  
Abiotic Conditions ◽  
Precise Control ◽  
Lotic Habitats ◽  
Precise Quantification ◽  
Lotic Environments ◽  
High Level

Experimental studies in rivers and streams are extremely difficult to run due to the fact that the conditions of these environments are very complex and provide a high level of heterogeneity, which hinders the precise control and standardization of variables. In this study, we present a practical sampler that was designed to make it easier to conduct research projects involving benthic communities of lotic environments, as well as a new nondestructive technique for quantification of the macroalgal communities typically found in these habitats. The sampler consists of an acrylic square tube in which water flows normally inside. This structure carries a removable glass plaque with a known area and can simulate various ecological situations by changing both biotic and abiotic conditions. Thus, it can mitigate the differences between environmental characteristics where each sampler is exposed. The new technique involves capturing digital images that can monitor a unique macroalgal community in development throughout time and a more precise quantification when compared with other techniques that are widely applied. The sampler is easy to build and the images simple to quantify, allowing the detection of spatial and temporal variations in richness and abundance of investigated communities.

scholarly journals Analysis and Comparison of Spatial–Temporal Entropy Variability of Tehran City Microclimate Based on Climate Change Scenarios

Entropy ◽  
2018 ◽  
Vol 21 (1) ◽  
pp. 13 ◽  
Author(s):  
Abdolazim Ghanghermeh ◽  
Gholamreza Roshan ◽  
José Orosa ◽  
Ángel Costa
Keyword(s):  
Climate Change ◽  
Global Warming ◽  
Shannon Entropy ◽  
Temperature Difference ◽  
Effective Temperature ◽  
Urban Climate ◽  
Temporal Variations ◽  
Future Climate Change ◽  
Climate Change Scenarios ◽  
Local Pressure

Urban microclimate patterns can play a great role for the allocation and management of cooling and heating energy sources, urban design and architecture, and urban heat island control. Therefore, the present study intends to investigate the variability of spatial and temporal entropy of the Effective Temperature index (ET) for the two basic periods (1971–2010) and the future (2011–2050) in Tehran to determine how the variability degree of the entropy values of the abovementioned bioclimatic would be, based on global warming and future climate change. ArcGIS software and geostatistical methods were used to show the Spatial and Temporal variations of the microclimate pattern in Tehran. However, due to global warming the temperature difference between the different areas of the study has declined, which is believed to reduce the abnormalities and more orderly between the data spatially and over time. It is observed that the lowest values of the Shannon entropy occurred in the last two decades, from 2030 to 2040, and the other in 2040–2050. Because, based on global warming, dominant areas have increased temperature, and the difference in temperature is reduced daily and the temperature difference between the zones of different areas is lower. The results of this study show a decrease in the coefficient of the Shannon entropy of effective temperature for future decades in Tehran. This can be due to the reduction of temperature differences between different regions. However, based on the urban-climate perspective, there is no positive view of this process. Because reducing the urban temperature difference means reducing the local pressure difference as well as reducing local winds. This is a factor that can effective, though limited, in the movement of stagnant urban air and reduction of thermal budget and thermal stress of the city.

Paleoclimatic reconstruction studies in lake sediments: major proxies, technical evolution and database

2020 ◽  
Author(s):  
Paula Bianchini ◽  
Elder Yokoyama ◽  
Luciana Prado
Keyword(s):  
Lake Sediments ◽  
Climate Changes ◽  
Environmental Changes ◽  
Drainage Basin ◽  
Spatial Scales ◽  
Temporal Variations ◽  
Quality Data ◽  
Anthropogenic Factors ◽  
Data Sets ◽  
Geochemical Composition

<p>Paleoclimate studies in different temporal and spatial scales provide important information on long-term statistics required to test hypotheses about climate changes. Comprehensive high-quality data sets and a solid understanding of dynamic climate processes in different temporal variations are essential to evaluate the sensitivity of the climatic system. Moreover, these data sets and dynamic analyses can help to distinguish the variability of natural and anthropogenic factors, reducing uncertainties about the magnitude and impact of future global climate changes. A common way to conduct paleoclimatic studies is through high resolution multiproxy lake sediments. Lake environments have been increasingly used in recent years to infer past fluctuations in climate, and many studies that comprise different locations and timescales demonstrate the great value of lakes as paleoclimatic archives. Because lake sediments are continental indicators sensitive to environmental changes, they can be used to reconstruct climate parameters, such as past rainfall, area management and environmental or limnological lake conditions. Changes of rainfall quantity can be recorded in lake archives by the variation of sedimentary input, which is related to changes in drainage basin and erosion rate. Beside of sedimentary input, lake sediments also exhibit physical and chemical changes in water bodies which, in turn, induce transformation in geochemical composition caused by changes in runoff or other allocated components. Thus, there is a variation in the proxies used in the studies, both in relation to the type of proxy used and the relationship used. In this context, we made a compilation of paleoclimatic studies on lake sediments (about 350 lakes), focusing on the main proxies used. Our study shows that there has been a change in the major proxies used along decades and with the emergence of new analysis techniques. In addition, we notice that lake characteristics (e.g., shape, geomorphological context, formation, etc.) have directly influence the proxies used and the quality of the information obtained. This compilation provides a database with an analysis of several lakes around the world, which can help future works and enable the identification of commonly used proxies according to the different variables that should be used, promoting more objective analyzes.</p>

scholarly journals Experimental studies of the aerodynamics of spinning and stationary footballs

2008 ◽  
Vol 222 (2) ◽  
pp. 195-205 ◽  
Author(s):  
M A Passmore ◽  
S Tuplin ◽  
A Spencer ◽  
R Jones
Keyword(s):  
Development Process ◽  
Experimental Studies ◽  
Field Trials ◽  
Considerable Effect ◽  
Product Development Process ◽  
Considerable Variability ◽  
Inherent Difficulty ◽  
Aerodynamic Parameters ◽  
Force Data ◽  
Flight Model

The accurate discrimination of the aerodynamic parameters affecting the flight of sports balls is essential in the product development process. Aerodynamic studies reported to date have been limited, primarily because of the inherent difficulty of making accurate measurements on a moving or spinning ball. Manufacturers therefore generally rely on field trials to determine ball performance, but the approach is time-consuming and subject to considerable variability. The current paper describes the development of a method for mounting stationary and spinning footballs in a wind tunnel to enable accurate force data to be obtained. The technique is applied to a number of footballs with differing constructions and the results reported. Significant differences in performance are noted for both stationary and spinning balls and the importance of the ball orientation to the flow is highlighted. To put the aerodynamic data into context the results are applied in a flight model to predict the potential differences in the behaviour of each ball in the air. The aerodynamic differences are shown to have a considerable effect on the flight path and the effect of orientation is shown to be particularly significant when a ball is rotating slowly. Though the techniques reported here are applied to a football they are equally applicable to other ball types.

scholarly journals Building Orientation as the Primary Design Consideration for Climate Responsive Architecture in Urban Areas

2020 ◽  
Vol 16 (1) ◽  
pp. 32-40
Author(s):  
Alisha Sinha
Keyword(s):  
Urban Areas ◽  
Future Research ◽  
Site Conditions ◽  
Design Consideration ◽  
Urban Context ◽  
Humid Climate ◽  
Climatic Regions ◽  
Responsive Architecture ◽  
Ideal Orientation ◽  
Responsive Design

Abstract Orientation is a design parameter that plays a major role in climate responsive architecture and helps achieve comfort within the built environment. However, it is difficult to achieve an ideal orientation, especially in urban context. The main aim of this paper is to develop alternate strategies to overcome the challenges faced in designing as per preferred orientation and then derive a set of tools that can help decide the orientation of a building on site both under normal and congested site conditions. Thereafter, the inferences from the paper can act as references for choosing an optimum orientation for placement of buildings in warm humid climate. It can act as a significant pedagogical guideline for students of architecture in deciphering solutions for a climate responsive design in a simplified manner. The results can also be utilised for future research in formulating similar tools for other climatic regions.

scholarly journals Chapter 13 — Developing a Preventive Pruning Program in Your Community: Mature Trees

EDIS ◽  
2007 ◽  
Vol 2007 (20) ◽  
Author(s):  
Edward F. Gilman ◽  
Amanda Bisson
Keyword(s):  
Urban Forest ◽  
Site Conditions ◽  
Mature Trees ◽  
Customer Expectations ◽  
Fact Sheet ◽  
Full Color ◽  
Recovery Program ◽  
Hurricane Recovery

ENH1063, a 14-page full color fact sheet by Edward F. Gilman and Amanda Bisson, is part of the Urban Forest Hurricane Recovery Program series. It describes seven main objectives, along with pruning types that help meet those objectives, which can be expanded or shortened to meet site conditions and customer expectations. It also describes how to determine a pruning cycle and how to implement a preventative pruning plan for mature trees. Published by the UF Department of Environmental Horticulture, September 2007. ENH1063/EP316: Chapter 13—Developing a Preventative Pruning Program: Mature Trees (ufl.edu)

scholarly journals Spatio-Temporal Vegetation Dynamic and Persistence under Climatic and Anthropogenic Factors

2020 ◽  
Vol 12 (16) ◽  
pp. 2612
Author(s):  
Barjeece Bashir ◽  
Chunxiang Cao ◽  
Shahid Naeem ◽  
Mehdi Zamani Joharestani ◽  
Xie Bo ◽  
...  
Keyword(s):  
Vegetation Dynamics ◽  
Arid Regions ◽  
Vegetation Index ◽  
Growing Season ◽  
Positive Development ◽  
Future Climate Change ◽  
Anthropogenic Factors ◽  
Climate Change Scenarios ◽  
Vegetation Activity ◽  
The Future

Land degradation reflected by vegetation is a commonly used practice to monitor desertification. To retrieve important information for ecosystem management accurate assessment of desertification is necessary. The major factors that drive vegetation dynamics in arid and semi-arid regions are climate and anthropogenic activities. Progression of desertification is expected to exacerbate under future climate change scenarios, through precipitation variability, increased drought frequency and persistence of dry conditions. This study examined spatiotemporal vegetation dynamics in arid regions of Sindh, Pakistan, using annual and growing season Normalized Difference Vegetation Index (NDVI) data from 2000 to 2017, and explored the climatic and anthropogenic effects on vegetation. Results showed an overall upward trend (annual 86.71% and growing season 82.7%) and partial downward trend (annual 13.28% and growing season 17.3%) in the study area. NDVI showed the highest significant increase in cropland region during annual, whereas during growing season the highest significant increase was observed in savannas. Overall high consistency in future vegetation trends in arid regions of Sindh province is observed. Stable and steady development region (annual 48.45% and growing 42.80%) dominates the future vegetation trends. Based on the Hurst exponent and vegetation dynamics of the past, improvement in vegetation cover is predicted for a large area (annual 44.49% and growing 30.77%), and a small area is predicted to have decline in vegetation activity (annual 0.09% and growing 3.04%). Results revealed that vegetation growth in the study area is a combined result of climatic and anthropogenic factors; however, in the future multi-controls are expected to have a slightly larger impact on annual positive development than climate whereas positive development in growing season is more likely to continue in future under the control of climate variability.

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