DOCSLIB.ORG

Lifehistory Evolution in Rangeshifting Populations

Total Page：16

File Type：pdf, Size：1020Kb

Download full-text PDF Read full-text
Lifehistory Evolution in Rangeshifting Populations CONCEPTS & SYNTHESIS EMPHASIZING NEW IDEAS TO STIMULATE RESEARCH IN ECOLOGY Ecology, 91(6), 2010, pp. 1617–1627 Ó 2010 by the Ecological Society of America Life-history evolution in range-shifting populations 1 BENJAMIN L. PHILLIPS, GREGORY P. BROWN, AND RICHARD SHINE School of Biological Sciences, University of Sydney, New South Wales 2006 Australia Abstract. Most evolutionary theory does not deal with populations expanding or contracting in space. Invasive species, climate change, epidemics, and the breakdown of dispersal barriers, however, all create populations in this kind of spatial disequilibrium. Importantly, spatial disequilibrium can have important ecological and evolutionary outcomes. During continuous range expansion, for example, populations on the expanding front experience novel evolutionary pressures because frontal populations are assorted by dispersal ability and have a lower density of conspecifics than do core populations. These conditions favor the evolution of traits that increase rates of dispersal and reproduction. Additionally, lowered density on the expanding front eventually frees populations on the expanding edge from specialist, coevolved enemies, permitting higher investment into traits associated with dispersal and reproduction rather than defense against pathogens. As a result, the process of range expansion drives rapid life-history evolution, and this seems to occur despite ongoing serial founder events that have complex effects on genetic diversity at the expanding front. Traits evolving on the expanding edge are smeared across the landscape as the front moves through, leaving an ephemeral signature of range expansion in the life-history traits of a species across its newly colonized range. Recent studies suggest that such nonequilibrium processes during recent population history may have contributed to many patterns usually ascribed to evolutionary forces acting in populations at spatial equilibrium. Key words: climate change; contemporary evolution; defense allocation; density dependence; dispersal rate; enemy escape; genotype ‘‘smearing’’; nonequilibrium processes; range shift; rapid life-history evolution; reproductive rate. INTRODUCTION Understanding the evolutionary forces at work during range shift is of more than theoretical interest. For The vast majority of evolutionary theory is predicated example, the rate at which invasive species spread is an on a reasonable simplifying assumption: that popula- important consideration in our attempts to manage their tions are at spatial equilibrium. By this, we mean that impacts (Travis and Park 2004). Such rates can be the habitat available to the population (or metapopula- radically modified by evolutionary shifts in life history tion) does not expand or contract in space. That (Holt et al. 2005, Phillips et al. 2008). The rates and assumption is often invalid, however. Populations move correlates of population expansion also affect our through space; ranges expand and contract, and understanding of historical biogeography and thus the dispersal barriers are surmounted (Vermeij 2005). In historical events that have generated current biodiversity this review, we argue that such nonequilibrium popula- (Schoonmaker and Foster 1991, Clark et al. 1998, Davis tions experience different selective forces than do et al. 2005). Range shifts are also critical to the impact populations in spatial equilibrium, and we suggest that of climate change on biodiversity, because species that range shift can have profound impacts on the evolution can physically track climate change are likely to face a of a species’ life history. These evolutionary forces can lower impact than those that cannot (Thomas et al. cause change in life history over ecological timescales. 2004, Mustin et al. 2009). If species’ life histories evolve during climate-induced range shift, then the ramifica- tions for biodiversity conservation may be far-reaching Manuscript received 24 May 2009; revised 1 September 2009; indeed. accepted 15 September 2009; final version received 18 October 2009. Corresponding Editor: J. J. Stachowicz. Any case of continuous range shift includes two 1 E-mail: [email protected] unavoidable aspects: on the edge of the range, an 1617 1618 BENJAMIN L. PHILLIPS ET AL. Ecology, Vol. 91, No. 6 invading population (1) is assorted by dispersal ability which habitat quality is homogenous and not limiting (i.e., only the best dispersers make it to the new range (and hence, a population is expanding into new suitable edge each generation), and (2) exhibits a lower-than- habitat). In these situations, where a species is shifting normal population density. These outcomes (which we its range, some very clear predictions emerge. In will explain in more detail) have at least three particular, during range expansion we can expect consequences for life-history evolution in the vanguard dispersal rates on the advancing front to evolve upward of invading populations: first, they encourage the due to spatial selection. evolution of increased dispersal rate; second, they encourage the evolution of increased reproductive rate; Spatial selection: a runaway evolutionary process and third, they lead to the extirpation of specialist Why do we expect dispersal to evolve upward on the enemies on the invasion front. expanding front during range advance? The shift is a natural consequence of range expansion and occurs due EVOLUTION OF DISPERSAL to a process that we refer to here as ‘‘spatial selection’’ Populations spread through a combination of dis- (Fig. 1). Imagine a population where all the individuals persal and population growth (Fisher 1937, Skellam disperse, then reproduce, and then die. If this population 1951). Traditionally, models of range advance suggested is placed into a large area of suitable vacant habitat, the waves of advance that traveled at constant speed, an population will advance its range as individuals disperse assumption at odds with many empirical observations. (Fig. 1A). Importantly, the process of dispersal effec- Theoretical advances in the last 30 years show that tively sorts individuals through space by dispersal accelerating range advance can arise from subtleties in ability. That is, individuals on the edge of the expanding how dispersal and population growth are modeled (Kot population front are at that edge simply because they et al. 1996, Shigesada and Kawasaki 1997, Hastings et dispersed farther than other individuals in the popula- al. 2005), but these models have continued to treat tion: the process of dispersal has spatially assorted the dispersal and population growth as constant through best dispersers in the population and placed them on the time. Here, we suggest that evolution often may drive expanding front (Fig. 1B). Now, because all the best changes in these critical parameters during invasion, and dispersers are in the same place at the same time, they thus accelerate range advance. YNTHESIS will tend to breed with each other (the ‘‘Olympic Village Dispersal, defined here as displacement between effect’’). Thus, if any component of dispersal ability is birth and reproduction (Ronce 2007), appears to be a &S heritable in this hypothetical species, the offspring of the highly labile trait (Roff and Fairbairn 2001, Bowler individuals on the front will tend to have higher and Benton 2005, Ronce 2007). Part of this lability dispersal ability than the offspring of individuals from stems from the trait’s complexity; dispersal can be the core of the population (Fig. 1C). If we imagine this achieved actively (in which case, numerous behavioral process occurring every generation as the population traits are important; Barton´et al. 2009), passively (in ONCEPTS expands, the process of spatial assortment for dispersal C which case, numerous morphological traits are impor- tant), or both; dispersal also can be condition ability behaves like a runaway evolutionary process, dependent (Ferriere et al. 2000, Bowler and Benton continually selecting for increased rates of dispersal on 2005). Even an apparently simple example, a wind- the advancing front. dispersed seed, will disperse according to its mass, the Density effects interact with this process of spatial height from the ground of its release, its buoyancy, the assortment. Indeed, the only process that can counteract timing of its release, and its tendency to settle. The the Olympic Village effect is an Allee effect, where low- complex phenotypic determinants of dispersal mean density populations confer lower survival or reproduc- that selection for enhanced rates of dispersal has tive rate on their members (Travis and Dytham 2002). In numerous phenotypic targets. the absence of such an effect, individuals near the When habitat is homogenous, natural selection on advancing front may actually benefit from a low-density dispersal is driven by issues such as the avoidance of environment (i.e., fewer conspecifics in their vicinity) inbreeding and competition (Hamilton and May 1977, and, as a consequence, leave more offspring. Those Ferriere et al. 2000, Clobert et al. 2001, Ronce 2007). offspring will tend to inherit their parent’s high dispersal Where habitat is heterogeneous (on range edges or in rates. Thus, in cases where Allee effects are weak relative dynamic metapopulations, for example), dispersal re- to the Olympic Village effect, dispersal rates will evolve sponds in complex ways to a combination of natural upward on the expanding front. Several simulation selection and spatial assortment by
Load more

Recommended publications
  • What Characteristics Do All Invasive Species Share That Make Them So
    Invasive Plants Facts and Figures Definition Invasive Plant: Plants that have, or are likely to spread into native or minimally managed plant systems and cause economic or environmental harm by developing self-sustaining populations and becoming dominant or disruptive to those systems. Where do most invasive species come from? How do they get here and get started? Most originate long distances from the point of introduction Horticulture is responsible for the introduction of approximately 60% of invasive species. Conservation uses are responsible for the introduction of approximately 30% of invasive species. Accidental introductions account for about 10%. Of all non-native species introduced only about 15% ever escape cultivation, and of this 15% only about 1% ever become a problem in the wild. The process that leads to a plant becoming an invasive species, Cultivation – Escape – Naturalization – Invasion, may take over 100 years to complete. What characteristics make invasive species so successful in our environment? Lack predators, pathogens, and diseases to keep population numbers in check Produce copious amounts of seed with a high viability of that seed Use successful dispersal mechanisms – attractive to wildlife Thrive on disturbance, very opportunistic Fast-growing Habitat generalists. They do not have specific or narrow growth requirements. Some demonstrate alleleopathy – produce chemicals that inhibit the growth of other plants nearby. Have longer photosynthetic periods – first to leaf out in the spring and last to drop leaves in autumn Alter soil and habitat conditions where they grow to better suit their own survival and expansion. Why do we care? What is the big deal? Ecological Impacts Impacting/altering natural communities at a startling rate.
    [Show full text]
  • Latitudinal Shifts of Introduced Species: Possible Causes and Implications
    Biol Invasions (2012) 14:547–556 DOI 10.1007/s10530-011-0094-8 ORIGINAL PAPER Latitudinal shifts of introduced species: possible causes and implications Qinfeng Guo • Dov F. Sax • Hong Qian • Regan Early Received: 26 January 2011 / Accepted: 22 August 2011 / Published online: 4 September 2011 Ó Springer Science+Business Media B.V. (outside the USA) 2011 Abstract This study aims to document shifts in the those in their native ranges. Only a small fraction of latitudinal distributions of non-native species relative species examined (i.e.\20% of animals and\10% of to their own native distributions and to discuss plants) have expanded their distributions in their possible causes and implications of these shifts. We exotic range beyond both high- and low-limits of used published and newly compiled data on inter- their native latitudes. Birds, mammals and plants continentally introduced birds, mammals and plants. tended to shift their exotic ranges in similar ways. In We found strong correlations between the latitudinal addition, most non-native species (65–85% in differ- distributions occupied by species in their native and ent groups) have not reached the distributional extent exotic ranges. However, relatively more non-native observed in their native ranges. The possible drivers species occur at latitudes higher than those in their of latitudinal shifts in the exotic range may include native ranges, and fewer occur at latitudes lower than climate change, greater biotic resistance at lower latitudes, historical limitations on ranges in native regions, and the impacts of humans on species Electronic supplementary material The online version of this article (doi:10.1007/s10530-011-0094-8) contains distributions.
    [Show full text]
  • Invasive Species and the Cultural Keystone Species Concept
    Copyright © 2005 by the author(s). Published here under license by the Resilience Alliance. Nuñez, M. A., and D. Simberloff. 2005. Invasive species and the cultural keystone species concept. Ecology and Society 10(1): r4. [online] URL: http://www.ecologyandsociety.org/vol10/iss1/resp4/ Response to Garibaldi and Turner. 2004. “Cultural Keystone Species: Implications for Ecological Conservation and Restoration” Invasive Species and the Cultural Keystone Species Concept Martin A. Nuñez1 and Daniel Simberloff1 Key Words: biological invasions ; cultural keystone species; conservation; exotic species; invasive species; keystone species The concept of the keystone species (Paine 1966, (Mooney and Hobbs 2000, Simberloff 2000), 1969, Power et al. 1996) has been a transformative serving as cultural icons in different areas of the notion in ecology. Keystone species were originally world. Examples of this include Eucalyptus in narrowly defined to be those whose importance to California, tomatoes (Lycopersicon esculentum) in community and ecosystem structure, composition, Italy, bluegrass (Poa pratensis) in Kentucky, and function is disproportionate to their abundance. Cannabis sativa in Jamaica, bananas (Musa Even this narrow definition fostered great insight paradisiaca) in Ecuador, horses (Equus caballus) into the nature of particular ecosystems and of in the western United States, coffee (Coffea spp) in threats to them (Power et al. 1996). However, in Colombia, and kudzu (Pueraria montana) in the ecological circles the term came to be more casually southeastern United States. used to mean any species that has a very large impact on the ecosystem, no matter how abundant it is More than 100 species of Australian Eucalyptus (Simberloff 2003), and this casual usage has led to trees have been brought to California since the late attacks on the concept on the grounds that it is so 19th century.
    [Show full text]
  • Can More K-Selected Species Be Better Invaders?
    Diversity and Distributions, (Diversity Distrib.) (2007) 13, 535–543 Blackwell Publishing Ltd BIODIVERSITY Can more K-selected species be better RESEARCH invaders? A case study of fruit flies in La Réunion Pierre-François Duyck1*, Patrice David2 and Serge Quilici1 1UMR 53 Ӷ Peuplements Végétaux et ABSTRACT Bio-agresseurs en Milieu Tropical ӷ CIRAD Invasive species are often said to be r-selected. However, invaders must sometimes Pôle de Protection des Plantes (3P), 7 chemin de l’IRAT, 97410 St Pierre, La Réunion, France, compete with related resident species. In this case invaders should present combina- 2UMR 5175, CNRS Centre d’Ecologie tions of life-history traits that give them higher competitive ability than residents, Fonctionnelle et Evolutive (CEFE), 1919 route de even at the expense of lower colonization ability. We test this prediction by compar- Mende, 34293 Montpellier Cedex, France ing life-history traits among four fruit fly species, one endemic and three successive invaders, in La Réunion Island. Recent invaders tend to produce fewer, but larger, juveniles, delay the onset but increase the duration of reproduction, survive longer, and senesce more slowly than earlier ones. These traits are associated with higher ranks in a competitive hierarchy established in a previous study. However, the endemic species, now nearly extinct in the island, is inferior to the other three with respect to both competition and colonization traits, violating the trade-off assumption. Our results overall suggest that the key traits for invasion in this system were those that *Correspondence: Pierre-François Duyck, favoured competition rather than colonization. CIRAD 3P, 7, chemin de l’IRAT, 97410, Keywords St Pierre, La Réunion Island, France.
    [Show full text]
  • The Effects of Introduced Tilapias on Native Biodiversity
    AQUATIC CONSERVATION: MARINE AND FRESHWATER ECOSYSTEMS Aquatic Conserv: Mar. Freshw. Ecosyst. 15: 463–483 (2005) Published online in Wiley InterScience (www.interscience.wiley.com). DOI: 10.1002/aqc.699 The effects of introduced tilapias on native biodiversity GABRIELLE C. CANONICOa,*, ANGELA ARTHINGTONb, JEFFREY K. MCCRARYc,d and MICHELE L. THIEMEe a Sustainable Development and Conservation Biology Program, University of Maryland, College Park, Maryland, USA b Centre for Riverine Landscapes, Faculty of Environmental Sciences, Griffith University, Australia c University of Central America, Managua, Nicaragua d Conservation Management Institute, College of Natural Resources, Virginia Tech, Blacksburg, Virginia, USA e Conservation Science Program, World Wildlife Fund, Washington, DC, USA ABSTRACT 1. The common name ‘tilapia’ refers to a group of tropical freshwater fish in the family Cichlidae (Oreochromis, Tilapia, and Sarotherodon spp.) that are indigenous to Africa and the southwestern Middle East. Since the 1930s, tilapias have been intentionally dispersed worldwide for the biological control of aquatic weeds and insects, as baitfish for certain capture fisheries, for aquaria, and as a food fish. They have most recently been promoted as an important source of protein that could provide food security for developing countries without the environmental problems associated with terrestrial agriculture. In addition, market demand for tilapia in developed countries such as the United States is growing rapidly. 2. Tilapias are well-suited to aquaculture because they are highly prolific and tolerant to a range of environmental conditions. They have come to be known as the ‘aquatic chicken’ because of their potential as an affordable, high-yield source of protein that can be easily raised in a range of environments } from subsistence or ‘backyard’ units to intensive fish hatcheries.
    [Show full text]
  • Seafood Watch Aquaculture Criteria
    1 ASC Shrimp Aquaculture Stewardship Council SHRIMP (final draft standards) Benchmarking equivalency results assessed against the Seafood Watch Aquaculture Criteria May 2013 2 ASC Shrimp Final Seafood Recommendation ASC Shrimp Criterion Score (0-10) Rank Critical? C1 Data 9.44 GREEN C2 Effluent 6.00 YELLOW NO C3 Habitat 4.04 YELLOW NO C4 Chemicals 10.00 GREEN NO C5 Feed 5.96 YELLOW NO C6 Escapes 4.00 YELLOW NO C7 Disease 4.00 YELLOW NO C8 Source 10.00 GREEN 3.3X Wildlife mortalities -4.00 YELLOW NO 6.2X Introduced species escape 0.00 GREEN Total 49.73 Final score 6.22 OVERALL RANKING Final Score 6.22 Initial rank YELLOW Red criteria 0 Final rank YELLOW Critical Criteria? NO FINAL RANK YELLOW Scoring note – scores range from zero to ten where zero indicates very poor performance and ten indicates the aquaculture operations have no significant impact, except for the two exceptional “X” criteria for which a score of -10 is very poor and zero is good. Scoring Summary ASC Shrimp has a final numerical score of 6.22 with no red criteria. The final recommendation is a yellow “Good Alternative”. 3 ASC Shrimp Executive Summary The benchmarking equivalence assessment was undertaken on the basis of a positive application of a realistic worst-case scenario • “Positive” – Seafood Watch wants to be able to defer to equivalent certification schemes • “Realistic” – we are not actively pursuing the theoretical worst case score. It has to represent reality and realistic aquaculture production. • “Worst-case scenario” – we need to know that the worst-performing farm capable of being certified to any one standard is equivalent to a minimum of a Seafood Watch “Good alternative” or “Yellow” rank.
    [Show full text]
  • Introduced Species and the Issue of Animal Welfare.Pdf
    'I A.S. Chamove et al. -Deep Woodchip Litter Original Article M Hutchins et al. -Introduced Species Original Article for Dairy Purposes, Technical Bulletin Isolation and Identification of Food Those who must make decisions about the fate of introduced species need to No. 17. HMSO, London. Poisoning Organisms, Society of Appli­ seek a balance between the rights of the individual animals and preserving the viabili­ Markowitz, H. and Woodworth, G. (1978) ed Bacteriology Technical series No. ty of whole ecosystems. One important consideration is that, although the control of Experimental analysis and control of 17. Academic Press, London (in press). exotic animal populations may adversely affect individual sentient beings, inaction group behavior. In: Markowitz, H. and Murphy, D.E. (1976) Enrichment and oc­ may cause widespread suffering to many species and consequent loss of biological Stevens, V.J ., eds., Behavior of Captive cupational devices for orangutans and diversity. Wild Animals. Nelson-Hall, Chicago, chimpanzees. lnt Zoo News 23: 24-26. IL. Olesiuk, O.M., Snoyenbos, G.H. and Smy­ Zusammenfassung McGrew, W.C. (1981) Social and cognitive ser, C.F. (1971) Inhibitory effects of used capabilities of nonhuman primates: les­ litter on Salmonella typhimurium trans­ Eine heftige Debatte betraf kUrzlich das Thema der Kontrolle oder Eliminierung sons from the wild to captivity. lnt j mission in the chicken. Avian Dis 15:118- von eingefUhrten oder "exotischen" Tieren auf Land in offentlichem (US) Besitz. Die Study Anim Prob 2:138-149. 124. EinfUhrung von Tierarten, ob beabsichtigt oder unbeabsichtigt, scheint ein unverme­ Meyer-Holzapfel, M. (1968) Abnormal be­ Snoeyenbos, G.H.
    [Show full text]
  • Effects of Nonindigenous Invasive Species on Water Quality and Quantity
    Effects of Nonindigenous Invasive Species on Water Quality and Quantity Frank H. McCormick1, Glen C. Contreras2, and Agency (EPA), more than one-third of all States have waters Sherri L. Johnson3 that are listed for invasive species under section 303d of the Clean Water Act of 1977. Nonindigenous species cause ecological damage, human health risks, or economic losses. Abstract Invasive species are degrading a suite of ecosystem services that the national forests and grasslands provide, including Physical and biological disruptions of aquatic systems recreational fishing, boating, and swimming; municipal, caused by invasive species alter water quantity and water industrial, and agricultural water supply; and forest products. quality. Recent evidence suggests that water is a vector for Degradation of these services results in direct economic the spread of Sudden Oak Death disease and Port-Orford- losses, costs to replace the services, and control costs. Losses, cedar root disease. Since the 1990s, the public has become damages, and control costs are estimated to exceed $178 billion increasingly aware of the presence of invasive species in annually (Daily et al. 2000a, 2000b). Although agriculture is the Nation’s waters. Media reports about Asian carp, zebra the segment of the economy most affected ($71 billion per mussels (Dreissena polymorpha), golden algae (Prynmesium year), costs to other segments, such as tourism, fisheries, and parvum), cyanobacteria (Anabaena sp., Aphanizomenon sp., water supply, total $67 billion per year. Although more difficult and Microcystis sp.), and New Zealand mud snail have raised to quantify, losses of these ecosystem functions also reduce public awareness about the economic and ecological costs of the quality of life.
    [Show full text]
  • Are Invasive Plants More Abundant in the Introduced Versus Native Range?
    Received: 22 March 2017 | Accepted: 27 September 2017 DOI: 10.1111/1365-2745.12881 RESEARCH ARTICLE Are exotic plants more abundant in the introduced versus native range? Dean E. Pearson1,2 | Özkan Eren3 | Yvette K. Ortega1 | Diego Villarreal4 | Muhyettin Şentürk3 | M. Florencia Miguel4 | C. Miguel Weinzettel4 | Aníbal Prina5 | José L. Hierro4,6 1Rocky Mountain Research Station, United States Forest Service, Missoula, MT, USA; 2The University of Montana, Missoula, MT, USA; 3Biyoloji Bölümü, Fen Edebiyat Fakültesi, Adnan Menderes Üniversitesi, Aydın, Turkey; 4Facultad de Ciencias Exactas y Naturales, Universidad Nacional de La Pampa (UNLPam), Santa Rosa, La Pampa, Argentina; 5Facultad de Agronomía, Universidad Nacional de La Pampa (UNLPam), Santa Rosa, La Pampa, Argentina and 6Instituto de Ciencias de la Tierra y Ambientales de La Pampa [INCITAP (CONICET-UNLPam)], Santa Rosa, La Pampa, Argentina Correspondence Dean E. Pearson Abstract Email: [email protected] 1. Many invasion hypotheses postulate that introducing species to novel environ- Funding information ments allows some organisms to escape population controls within the native range Presidents Early Career Award for Science and to attain higher abundance in the introduced range. However, introductions may Engineering, Grant/Award Number: NA also allow inherently successful species access to new regions where they may Handling Editor: Peter Alpert flourish without increasing in abundance. 2. To examine these hypotheses, we randomly surveyed semi-arid grasslands in the native and two introduced ranges (12,000–21,000 km2 per range) to quantify local abundance (mean cover per occupied plot) and occurrence (percentage of 1-m2 plots occupied) for 20 plant introductions that included pest and non-pest species.
    [Show full text]
  • Invasive and Other Problematic Species, Genes and Diseases
    Invasive and Other Problematic Species, Genes and Diseases The threat category ‘invasive and other problematic species, genes and diseases’ (IUCN 8) includes both native and non-native plants, animals, pathogens, microbes, and genetic materials that have or are predicted to have harmful effects on biodiversity following their introduction, spread and/or increase in abundance. This definition encompasses a broad array of organisms, and the types of impacts to native species and habitats are equally variable. It includes invasive species that were not present in New Hampshire prior to European settlement, and have been directly or indirectly introduced and spread into the state by human activities. A variety of wildlife species are vulnerable to increased predation from both native and non-native animals. Many species are also affected by diseases and parasites, including white-nose syndrome in bats, fungal pathogens in reptiles, and ticks and nematodes in moose. Native and non-native insects act as forest pests, damaging or killing native tree species and causing significant changes to wildlife habitats. Native tree species can also be affected by non-native fungal pathogens. Invasive plants can compete with native species for nutrients, water and light, and can change the physical environment by altering soil chemistry. Risk Assessment Summary Invasive species affect all 24 habitats and 106 SGCN. This is second only to pollution in the number of species affected. The majority of threat assessment scores were ranked as low (n=116, 51%), followed by moderate (n = 83, 37%) and high (n = 26, 12%). Only the moderate and high-ranking threats are summarized for each category in Table 4-17.
    [Show full text]
  • Seafood Watch Aquaculture Standard
    1 Aquaculture Stewardship Council Salmon Standard (Version 1.1 June 2017) Benchmarking equivalency results assessed against the Seafood Watch Aquaculture Standard June 2017 2 Final Seafood Recommendation ASC Salmon Criterion Score (0-10) Rank Critical? C1 Data 9.77 GREEN C2 Effluent 5.00 YELLOW NO C3 Habitat 6.27 YELLOW NO C4 Chemicals 4.00 YELLOW NO C5 Feed 3.36 YELLOW NO C6 Escapes 2.00 RED NO C7 Disease 5.00 YELLOW NO C8X Source 0.00 GREEN NO C9X Wildlife mortalities -4.00 YELLOW NO C10X Introduced species escape 0.00 GREEN Total 31.40 Final score 4.49 Final Score 4.49 Initial rank YELLOW Red criteria 1 Final rank YELLOW Critical Criteria? NO FINAL RANK YELLOW Scoring note – scores range from zero to ten where zero indicates very poor performance and ten indicates the aquaculture operations have no significant impact. Color ranks: Red = 0 to 3.33, Yellow = 3.34 to 6.66, Green = 6.66 to 10. Criteria 8X, 9X, and 10X are exceptional criteria, where 0 indicates no impact and a deduction of -10 reflects very poor performance. Two or more Red criteria trigger a Red final result. Scoring summary The final numerical score for the ASC Salmon Standard benchmarked against the Seafood Watch Aquaculture Standard is 4.49 out of 10. With only one Red-ranked criterion (Escapes), the final result is a “Good Alternative” recommendation. 1 Executive Summary The benchmarking equivalence assessment was undertaken on the basis of a positive application of a realistic worst-case scenario “Positive” – Seafood Watch wants to be able to defer to equivalent certification schemes “Realistic” – we are not actively pursuing the theoretical worst case score.
    [Show full text]
  • Invasive Species Risk
    USEPA Office of Water Recovery Potential Screening Website 09/01/2011 http://www.epa.gov/recoverypotential/ Recovery Potential Metrics Summary Form Indicator Name: INVASIVE SPECIES RISK Type: Stressor Exposure Rationale/Relevance to Recovery Potential: Non-indigenous species (NIS) invasions are widely known to disrupt aquatic system function and inhibit recovery of altered systems. The rapid colonization typical of NIS may act to subvert expected succession pathways and thereby disrupt restoration planning. Altered structure due to aquatic or riparian NIS can reduce shade, inhibit native riparian vegetation cover, and increase sedimentation. Aquatic invaders may compete directly or prey upon key native species, reduce numbers or species diversity, and markedly alter food webs and ecological structure. Presence of aquatic or riparian NIS may actually be the impairment cause for listing, and recovery in such cases depends on eradication or control. Particularly relevant to recovery potential screening is the fact that some NIS, once established, cannot currently be controlled or eradicated by any known methods. See literature excerpts below for more effects. How Measured: In recovery potential screening, this metric may consider existing invasions or the risk of future invasions, or both. Many options for scoring can be developed, based on the state. An example quantile scoring process is: 0 – no established NIS of concern, no immediate risk 1 – no established NIS of concern, risk due to proximity or other vulnerability 2 -- established NIS of concern exists, control or eradication feasible 3 – established NIS of concern exists, control or eradication infeasible This scoring approach can be customized for NIS species-specific rankings, direct influence on prospects of reattaining the unmet water quality standard, or to consider multiple NIS problems per waterbody.
    [Show full text]