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Keystone and Indicator Species
Published in Yeqiao Wang, Terrestrial Ecosystems and Biodiversity, 2020
I view the indicator species concept broadly—that is, they are species whose status and trends provide insights into environmental conditions that extend beyond their own measurement.[3,4] Indicator species can be used as surrogates for ecosystem processes or conditions that are too difficult or costly to measure directly. The primary role of ecological indicators, in general, and indicator species in particular, is to measure the response of the ecosystem to anthropogenic disturbance.[5] Selection of indicator species is a critical aspect of most environmental monitoring programs. For example, indicator species with known stress–response relationships are often chosen as early warning sentinels of impending stressor effects so as to avoid undesirable or irreversible environmental outcomes.
Seabirds as Indicators of Forage Fish Stocks
Published in Jaime A. Ramos, Leonel Pereira, Seabird Biodiversity and Human Activities, 2022
Jaime A. Ramos, Robert W. Furness
Ecological indicators are appealing for scientists, managers, politicians and the general public (Niemi and MacDonald 2004), because they convey (often complex) information about the state of the environment in a relatively easy way, and may provide an early warning signal for ecological problems or be used as monitors for trends in ecological resources. However, to be effective, they should capture the complexity of the ecosystem concerned, and at the same time, be simple enough to be understood and cost effective to be routinely monitored (Dale and Beyler 2001). Seabirds may provide ecological indicators to show the general condition or ‘health’ of aquatic ecosystems, in which case they provide a qualitative indicator and are often referred as sentinel species (Furness and Camphuysen 1997), or they may show a specific functional relationship with a specific stressor, in which case they may be used as a quantitative ecological indicator (Piatt et al. 2007). Seabirds are suitable candidates to act as ecological indicators, because they are conspicuous top predators likely integrating ecosystems processes occurring at lower trophic levels (Frederiksen et al. 2006), easy to monitor on land and there are many long-term studies of seabird populations worldwide. However, to be ideal indicators of changes in fish stocks seabird measures should show linear relationships along the full range of fish stock variation encountered by seabirds (Dale and Beyler 2001). A first word of caution is needed because different seabird reproductive and behavioural measures are likely to respond differently to variations in forage fish, and responses vary among species (Montevecchi 1993, Furness and Camphuysen 1997).
Elements of Applying a Whole System Design Approach (Elements 1–5)
Published in Peter Stasinopoulos, Michael H. Smith, Karlson ‘Charlie’ Hargroves, Cheryl Desha, Whole System Design, 2013
Peter Stasinopoulos, Michael H. Smith, Karlson ‘Charlie’ Hargroves, Cheryl Desha
Ecological indicators are tools that estimate the hidden ecological impacts of resources. Several quantitative and qualitative ecological indicators have been developed. With so many similar ecological indicators available, it is important to understand the underlying assumptions and ensure that the selected (or developed) indicators are effective for the application. Generally, effective ecological indicators meet the following conditions:30They are simple, yet reflect essential environmental stress factors;They are scientifically defensible, albeit not necessarily scientifically complete;They are based on characteristics that are common to all processes, goods and services;The selected characteristics are straightforwardly measurable or calculable, irrespective of geographic location;Obtaining results with these measures is cost-effective and timely;The measures permit the transparent and reproducible estimation of environmental stress potentials of all conceivable plans, processes, goods and services throughout the system's life;Their use always yields directionally safe answers;They form a bridge to economic models; andThey are acceptable and usable at all levels: local, regional and global.
Ecological health analysis of wetlands in the middle reaches of Yangtze River under changing environment
Published in International Journal of Digital Earth, 2023
Shengqing Zhang, Xiaoyan Zhai, Peng Yang, Jun Xia, Sheng Hu, Libo Zhou, Cai Fu
In recent years, remote sensing has become essential for studying natural environments due to easy access to large and varied data and timeliness in analyses (Shi, Zhao, and Han 2010). The development of remote sensing technologies provides a large amount of data to support the assessment of environmental quality and to monitor ecological (Willis 2015). Various ecological indicators (e.g. forest area (Ochoa-Gaona et al. 2010), grassland (Sullivan et al. 2010), green space (Gao et al. 2020), cities (Gupta et al. 2012), and water bodies (Xu 2006)), can be easily calculated from easily accessible remote sensing data, which are widely used in research to monitor ecological quality and environmental problems. Although single indicators are easy to calculate and accessible in large quantities, multiple indicators can better reflect the spatial and temporal variation of regional ecology and provide more information to facilitate research (Hu and Xu 2018). Therefore, to better analyze ecological conditions and patterns of change, several single indices synthesized as ecological composite indices have been combined with remote sensing techniques to assess regional ecological changes (Foody 2007). Currently, remote sensing is one of the most important tools for obtaining the status of regional wetlands, the key to ecological evaluation and identification (Rashid and Aneaus 2020).
Spatio-temporal variations in the ecological vulnerability of the Upper Mzingwane sub-catchment of Zimbabwe
Published in Geomatics, Natural Hazards and Risk, 2023
Bright Chisadza, France Ncube, Margaret Macherera, Tsitsi Bangira, Onalenna Gwate
A conceptual framework integrating external ecological variables (socio-economic and land resources) and internal ecological variables (hydro climate and topography) was developed for the assessment of EV over the Upper Mzingwane sub-catchment from 1990 to 2020 (Figure 2). The weighting of the indicators was based on objective PCA eigenvalue weighing processes. The approach is based on the inherent characteristics of the ecological indicators (Wei et al. 2020). EVs were categorised into specific groups, such as hydro climate, socio-economic, land resources, and topography vulnerabilities, to obtain a comprehensive picture of the extent of EVs in the entire Upper Mzingwane sub-catchment. Finally, the group vulnerabilities were overlayed using AHP-derived weights to produce the overall EV maps for the study years.