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The Functional Significance of Selection of Particles by Aquatic Animals during Building Behavior
Published in Roger S. Wotton, The Biology of Particles in Aquatic Systems, 2020
Communities associated with biogenic refugia are generally richer in individuals, and species, than surrounding areas.13,108,121,225–227 The effect is due, in part, to facilitation of larval recruitment and survival,228–230 a result of alteration of near-bed flow regimes by tubes and mounds influencing rates of larval immigration and settlement.228 Simulated tubes, including straws and needles, mimic the effects of natural tubes, and have highly localized consequences that are consistent with an influence of the artifact on near-bed current flow.121,229,231 However, laboratory flume studies indicate that projecting tubes cause local scouring of the bed,232 implying that hydrodynamic stabilization of the sediments by tubes may be an exception rather than the rule. This contradiction between field and laboratory studies could result from the mucous binding of particles by animals, diatoms, or bacteria in nature.232
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Published in R.N. Gibson, R.J.A. Atkinson, J.D.M. Gordon, Harold Barnes, Oceanography and Marine Biology, 2010
Georgios Tsounis, Sergio Rossi, Richard Grigg, Giovanni Santangelo, Lorenzo Bramanti, Josep-Maria Gili
The implementation of marine protected areas may be an important measure to ensure the biodiversity of nearby commercial areas if refugia are large enough and interconnected. In contrast, traditional rotation systems (in use since the Middle Ages) that harvest one stock and then work on others while the exhausted one is left to recover are problematic. The severe depletion of one stock is not in line with habitat management because it does not account for the ecological services of the corals. If the spatial scale chosen is too broad, overharvesting of one area may interrupt the gene flow between coral populations, as well as of invertebrate and fish populations seeking shelter in their branches. Therefore, management should instead monitor the fishery ensuring that no age class is eliminated completely. The present precious coral fisheries are far from this ideal, but lessons could be learned by examining the plenter principle that is applied to terrestrial forestry (O’Hara et al. 2007). As a starting point, given the lack of models, the maximum size of colonies in a population could be determined by ROV transects and a percentage of them prohibited from being harvested to maintain habitat structure. In a way, this approach would add maximum size limits (protecting habitat structure and thus biodiversity) to the already common minimum size limits and protect the reproductive potential.
Seabirds as Indicators of Oceanographic Changes
Published in Jaime A. Ramos, Leonel Pereira, Seabird Biodiversity and Human Activities, 2022
Sea-level rise, caused by global warming, may flood breeding colonies at coastal sites, such as those of terns, boobies or tropicbirds (Hatfield et al. 2012), thus affecting their breeding success and sometimes adult survival. This can be particularly negative for populated seabird colonies in tropical regions, which frequently breed in shallow islets, overcrowded with multiple seabird species and occupying all available space until the high tide line. Projected sea-level rise can thus create ecological traps, especially for tropical seabirds. An anticipated planning of potential climate change effects and installation of higher elevation seabird refugia should help mitigate the issue (Reynolds et al. 2015).
Lake management: is prevention better than cure?
Published in Inland Waters, 2022
Bryan M. Spears, David P. Hamilton, Yang Pan, Chu Zhaosheng, Linda May
Julius et al. (2008) conducted an analysis of resilience to climate change for various ecosystem types in the United States. The authors reported on the levels of agreement between indicators of expert opinion and the quality of the evidence available to support the implementation of effective climate change mitigation measures, producing a confidence rating. In general, the level of confidence in mitigation options for freshwater ecosystems was low for both indicators, as found in our case studies. However, relatively novel approaches to lake management have been proposed by Julius et al. (2008) to address this problem. These approaches include creating refugia for migrant species (e.g., Chester and Robson 2013), relocating sensitive native species to high quality ecosystems (e.g., Winfield et al. 2004), creating replicate ecosystems within a specific area to provide protection against biodiversity loss (e.g., to control the spread of invasive species; Peters and Lodge 2013), and reducing other anthropogenic stressors to offset the effects of climate change (Hamilton et al. 2016a, Paerl et al. 2016). The wider applicability and effectiveness of these and other novel interventions should be considered further.
Walleye inland lake habitat: considerations for successful natural recruitment and stocking in North Central North America
Published in Lake and Reservoir Management, 2020
Joshua K. Raabe, Justin A. VanDeHey, Douglas L. Zentner, Timothy K. Cross, Greg G. Sass
Managers will have limited control over increasing water temperatures (Carpenter et al. 2017), so they should identify lakes that will be resilient to change such as those with thermal refuges or contain limited bass (Jacobson et al. 2010, Van Zuiden and Sharma 2016, Hansen et al. 2017, 2018). Similarly, managers should attempt to maintain connectivity to other lakes or systems that do provide adequate thermal refuges during critical periods. Physical habitat conservation and enhancement projects (e.g., shoreline vegetation, macrophytes, coarse woody habitat additions) may be able to provide localized, minor thermal refugia (Sass et al. 2019).
How does sediment supply influence refugia availability in river widenings?
Published in Journal of Ecohydraulics, 2021
Cristina Rachelly, Kate L. Mathers, Christine Weber, Volker Weitbrecht, Robert M. Boes, David F. Vetsch
Disturbance intensity may vary widely between habitats due to their spatial arrangement, substrate characteristics, or the acting hydraulic forces (Weber et al. 2013). Habitats that mitigate the effects of a disturbance on the biota and enable organisms to resist the disturbance are typically referred to as refugia (Lake 2000). They exist at various spatial and temporal scales (e.g. Sedell et al. 1990; Lancaster and Belyea 1997; Lancaster 2000) and their refugia function depends on various factors such as the disturbance type (e.g. Lake 2000), organism characteristics (e.g. Pearsons et al. 1992; Weber et al. 2013; Sueyoshi et al. 2014), substrate composition (e.g. Mathers et al. 2019), and hydro-morphological conditions (e.g. Lancaster and Hildrew 1993; Rice et al. 2007). Examples of local flood refugia are low bed shear stress zones (e.g. Lancaster and Hildrew 1993; Winterbottom et al. 1997; Lancaster 2000), specific turbulent eddies (e.g. Schwartz and Herricks 2005), marginal zones (e.g. Rempel et al. 1999), individual stones (e.g. Townsend et al. 1997; Matthaei et al. 2000), or woody debris (e.g. Palmer et al. 1996). On a larger scale, the floodplain (e.g. Matthaei and Townsend 2000; Schwartz and Herricks 2005), the hyporheic zone (e.g. Dole-Olivier et al. 1997; Stubbington 2012), or tributaries (e.g. Sueyoshi et al. 2014) may serve as refugia. It is commonly assumed that the closer a reach is to its natural state the more heterogeneous its habitats will be, thereby providing ample refugia opportunities under a range of hydrological conditions (Sedell et al. 1990; Pearsons et al. 1992; Gjerløv et al. 2003). In particular, a more morphologically and hydraulically complex reach will likely preserve low bed shear stress zones during periods of elevated discharge (e.g. Pearsons et al. 1992; Lancaster and Hildrew 1993).