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Agroecosystem diversity
Published in Stephen R. Gliessman, V. Ernesto Méndez, Victor M. Izzo, Eric W. Engles, Andrew Gerlicz, Agroecology, 2023
Stephen R. Gliessman, V. Ernesto Méndez, Victor M. Izzo, Eric W. Engles, Andrew Gerlicz
Diversity has an important role in maintaining ecosystem structure and function. Ever since Tansley (1935) coined the term “ecosystem” to refer to the combination of plant and animal communities and their physical environment, ecologists have attempted to demonstrate the relationship between the diversity of a system and its stability. Natural ecosystems generally conform to the principle that greater diversity allows greater resistance to perturbation and disturbance. Ecosystems with high diversity tend to be more resilient—to be able to recover from disturbance and restore balance in their processes of material cycling and energy flow. In ecosystems with low diversity, disturbance can more easily cause permanent shifts in functioning, resulting in the loss of resources from the ecosystem and changes in its species makeup.
Current practices, problems and the future
Published in John Endicott, Deep Excavations in Soil, 2020
For a designer, the principal technical risk is dealing with uncertainty as to the ground conditions. The methods of mitigating this risk are discussed in Section 3.6. The procedure is to investigate the site, gathering as much information about the ground conditions as possible. Next is to conduct a GI by exploratory drilling, sampling, testing and profiling between drillholes. Of necessity, the GI does not investigate all the ground. For example, samples are often taken at 74mm diameter, and drillholes at the design stage might be 10m apart. In such a case, each drillhole recovers less than 0.005% of the ground, less than one part in 10,000. In assessing, the types of soil present beneath a site and their distribution require judgement and experience. Drilling can disturb the ground, and sampling and transportation can disturb samples. In most cases, disturbance weakens soil, and adopting the properties of disturbed soil can be conservative. However, some loose soils when disturbed can become denser and correspondingly stronger and stiffer than undisturbed soil. Modern codes of practice such as Eurocode 7 [15] recommend not only taking a moderately conservative evaluation of the properties of the ground but also to apply partial factors on the properties of materials in order to allow for the variable characteristic of the ground.
Legislation and Policies Governing the Environmental and Health Impacts of Metallic Waste
Published in Sehliselo Ndlovu, Geoffrey S. Simate, Elias Matinde, Waste Production and Utilization in the Metal Extraction Industry, 2017
Sehliselo Ndlovu, Geoffrey S. Simate, Elias Matinde
The effects of the mining and metallurgical activities go beyond what has already been discussed in various sections of this chapter to include land degradation and noise pollution. For example, mining can cause physical disturbances to the landscape, creating eyesores such as waste rock piles and open pits (Barreto, 2007; Higginson and Wheeler, 2010; Chattopadhyay and Chattopadhyay, 2013). Such disturbances may contribute to the decline of wildlife and plant species in an area. In addition, it is possible that many of the pre-mining surface features cannot be replaced after the mining ceases. Mine subsidence (ground movements of the earth’s surface due to the collapse of overlying strata into voids created by underground mining) can cause damage to buildings and roads. When the soil is removed during mining, vegetation is also removed thus exposing the soil to erosion. As a result, sediments, typically from increased soil erosion, cause siltation and the smothering of streambeds. This siltation affects fisheries, swimming, domestic water supply, irrigation and other uses of streams.
Integration of Landsat time-series vegetation indices improves consistency of change detection
Published in International Journal of Digital Earth, 2023
Mingxing Zhou, Dengqiu Li, Kuo Liao, Dengsheng Lu
Vegetation controls the exchange of carbon, water, momentum and energy between the land and the atmosphere, and provides food, fibre, fuel and other ecosystem services (Haberl et al. 2007; Bonan, Pollard, and Thompson 1992). Vegetation changes can be grouped into three categories: (1) seasonal, caused by vegetation phenology; (2) gradual, caused by climate change, vegetation growth, and degradation in longer-term processes; and (3) abrupt, caused by natural and human disturbance such as wildfire, typhoon, earthquake, urbanization, deforestation, and afforestation (Verbesselt et al. 2010; Fang et al. 2018; Zhu et al. 2016; Li et al. 2021). Abrupt and gradual change refer to trend component beyond the seasonal variation (De Jong et al. 2012). They have critical impacts on long-term vegetation composition and structure, and stability. It is important to systematically collect information on abrupt and gradual changes as indicators of vegetation response to climate change and human activities.
Toward digital twins for sawmill production planning and control: benefits, opportunities, and challenges
Published in International Journal of Production Research, 2023
Sylvain Chabanet, Hind Bril El-Haouzi, Michael Morin, Jonathan Gaudreault, Philippe Thomas
Like any industry subject to international competition, sawmills are subject to pressure to increase their competitiveness and optimise their production processes. Shahi (2016), for example, touches upon the case of the Canadian forest industry which suffered in the past decades from the combined effects of globalisation, changes in the housing market, and a fluctuating currency. Climate change is expected to have an important impact on forests and timber supply. Brecka, Shahi, and Chen (2018), for example, studied the impact of climate change on boreal forests and timber supply and conclude that the increased tree growth rate induced by a warmer climate and more CO2 in the atmosphere does not compensate for the increased tree mortality from forest disturbance such as insects, fire, and drought. This leads to a decrease in the net volume of wood. They also argue that the quality of timber is likely to decline because of the accelerated growth rate. Further, the benefits of wood products, particularly wood construction for CO2 sequestration, have been widely studied (Himes and Busby 2020).
The future of temporary wetlands in drylands under global change
Published in Inland Waters, 2021
Gema Parra, Francisco Guerrero, Javier Armengol, Luc Brendonck, Sandra Brucet, C. Max Finlayson, Luciana Gomes-Barbosa, Patrick Grillas, Erik Jeppesen, Fernando Ortega, Rafael Vega, Tamar Zohary
A timely and urgent goal for wetland scientists is to understand the main mechanisms associated with disturbance by extreme drought, reduced resilience, and effects on aquatic biodiversity and ecosystem functioning in different scenarios. The concept of ecological resilience must be reconciled with natural disturbances and human impacts (Angeler 2021) to establish more efficient management strategies. Analysis of paleo-wetlands can provide a rich archaeological history that shows recent intensification of human stressors (Rueda Galán et al. 2021) against a background of natural disturbances. Emergent behaviours and properties should be identified to anticipate the future and identify solutions. Research networks operating at different levels (form local to international) and the collaboration with all the stakeholders would promote the sharing of knowledge and solutions to problems that enhance protection of these endangered aquatic systems.