Habitat Fragmentation and Extinction Risk of Lahontan Cutthroat Trout

Dunham, Jason B.; Vinyard, Gary L.; Rieman, Bruce E.

doi:10.1577/1548-8675(1997)017<1126:hfaero>2.3.co;2

Cited by 124 publications

(114 citation statements)

References 14 publications

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“…For example, if an event causing local extinctions is short-lived, migratory fish outside of the system at the time of disturbance can repopulate natal habitats. This mechanism has been invoked to explain repopulation of habitats following local extirpations caused by wildfires, droughts, and pollution (Dunham et al 1997;Rieman et al 1997;Knutsen et al 2001). If disturbances causing local extirpations are smaller than the natal patch size, smaller-scale or ''within-patch'' connectivity can be important for repopulation and persistence (Armstrong et al 1994;Rieman et al 1997;Dunham et al 2003).…”

Section: S a L M O Ni D E C O L Og Y A N D C O N Ne C T I V I T Ymentioning

confidence: 99%

Assessing connectivity in salmonid fishes with DNA microsatellite markers

Neville¹,

Dunham²,

Peacock³

2006

Connectivity Conservation

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Section: S a L M O Ni D E C O L Og Y A N D C O N Ne C T I V I T Ymentioning

confidence: 99%

Assessing connectivity in salmonid fishes with DNA microsatellite markers

Neville¹,

Dunham²,

Peacock³

2006

Connectivity Conservation

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“…Patterns of patch occupancy in a metapopulation fundamentally depend on patch-specific rates of local extinction and recolonization. Available evidence suggests fish populations are more likely to occur, and thus persist, in larger, less isolated habitats (Dunham et al, 1997;Rieman and McIntyre, 1995;Dunham and Rieman, 1999;Dunham et al, 2002).…”

Section: Stability and Persistence In Dynamic Landscapesmentioning

confidence: 99%

Effects of fire on fish populations: landscape perspectives on persistence of native fishes and nonnative fish invasions

Dunham

Young

Gresswell

et al. 2003

Forest Ecology and Management

142

134

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Our limited understanding of the short and long-term effects of fire on fish contributes to considerable uncertainty in assessments of the risks and benefits of fire management alternatives. A primary concern among the many potential effects of fire is the effects of fire and fire management on persistence of native fish populations. Limited evidence suggests vulnerability of fish to fire is contingent upon the quality of affected habitats, the amount and distribution of habitat (habitat fragmentation), and habitat specificity of the species in question. Species with narrow habitat requirements in highly degraded and fragmented systems are likely to be most vulnerable to fire and fire-related disturbance. In addition to effects of fire on native fish, there are growing concerns about the effects of fire on nonnative fish invasions. The role of fire in facilitating invasions by nonnative fishes is unknown, but experience with other species suggests some forms of disturbance associated with fire may facilitate invasion. Management efforts to promote persistence of fishes in fire-prone landscapes can take the form of four basic alternatives: (1) prefire management; (2) post-fire management; (3) managing fire itself (e.g. fire fighting); and (4) monitoring and adaptive management. Among these alternatives, pre-fire management is likely to be most effective. Effective pre-fire management activities will address factors that may render fish populations more vulnerable to the effects of fire (e.g. habitat degradation, fragmentation, and nonnative species). Post-fire management is also potentially important, but suffers from being a reactive approach that may not address threats in time to avert them. Managing fire itself can be important in some contexts, but negative consequences for fish populations are possible (e.g. toxicity of fire fighting chemicals to fish). Monitoring and adaptive management can provide important new information for evaluating alternatives, but proper implementation is often hampered by inadequate study designs and inconsistent financial and institutional support. The challenge for providing better management guidelines will be to add solid empirical data and models to assess the relevance of emerging concepts and theories, and provide a sense of where and when fires pose significant risks and/or benefits to fishes. Published by Elsevier Science B.V.

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“…However, little of this work has been translated into aquatic systems, despite the fact that landscape and riverine ecology share many attributes and organizing principles (Benda et al 2004), including the concept of connectivity (Wiens 5 2002). The degree of connectivity or isolation of a watershed is reflected in the productivity (Dryden and Stein 1975;Baker and Votapka 1990;Stanford et al 1996), species composition (Sheldon 1987(Sheldon , 1988Spens et al 2007), extinction risk (Dunham et al 1997;Fagan et al 2002;Morita and Yamamoto 2002), population size (Preston 1962a, b), genetic stability (Morita and Yamamoto 2002;Wofford et al 2005), morphological characteristics (Reznick 1982;Crossin et 10 al. 2004), life history (Dingle 1996), and ability of the biota to recover from disturbance (Stanford et al 1996).…”

Section: Introductionmentioning

confidence: 99%

A new measure of longitudinal connectivity for stream networks

Côté¹,

et al. 2008

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Habitat connectivity is a central factor in shaping aquatic biological communities, but few tools exist to describe and quantify this attribute at a network scale in riverine systems. Here, we develop a new index to quantify longitudinal connectivity of river networks based on the expected probability of an organism being able to move freely between two random points of the network.We apply this index to two fish life histories and evaluate the effects of the number, passability, and placement of barriers on river network connectivity through the use of simulated dendritic ecological networks. We then extend the index to a real world dendritic river system in Newfoundland, Canada.Our results indicate that connectivity in river systems, as represented by our index, is most impacted by the first few barriers added to the system. This is in contrast to terrestrial systems, which are more resilient to low levels of connectivity. The results show a curvilinear relationship between barrier passability and structural connectivity. This suggests that an incremental improvement in passability would result in a greater improvement to river network connectivity for more permeable barriers than for less permeable barriers. Our analysis of the index in simulated and real river networks also showed that barrier placement played an important role in connectivity.Not surprisingly, barriers located near the river mouth have the greatest impact on fish with diadromous life histories while those located near the center of the river network have the most impact on fish with potadromous life histories. The proposed index is conceptually simple and sufficiently flexible to deal with variations in river structure and biological communities. The index will enable researchers to account for connectivity in habitat studies and will also allow resource managers to characterize watersheds, assess cumulative impacts of multiple barriers and determine priorities for restoration.Response to Reviewers: July 21, 2008 To the Editor of Landscape Ecology, Thank you for your thorough review of our manuscript "A riverscape connectivity index" (LAND-08-1528R1). We have addressed each criticism and comment (see indented comments added to the LE decision letter below). In particular we have significantly shortened the introduction, replaced the simulated single channel system with that of a dendritic, added a conceptual cartoon and have Thank you for your submission to Landscape Ecology. Your paper has been recommended for publication with revisions. The reviews were all positive-each indicating that the connnectivity index is a valuable contribution to the aquatic landscape ecology literature. All of the reviewers suggest, and I concur that the manuscript is far too long, and thus, your major task in the revision will be to reduce the length substantially. The second issue, again raised by Reviewer # 1 is to address the issue of travel distance versus stream length. That reviewer presents a logical arguement that these two measures are no...

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Habitat Fragmentation and Extinction Risk of Lahontan Cutthroat Trout

Cited by 124 publications

References 14 publications

Assessing connectivity in salmonid fishes with DNA microsatellite markers

Assessing connectivity in salmonid fishes with DNA microsatellite markers

Effects of fire on fish populations: landscape perspectives on persistence of native fishes and nonnative fish invasions

A new measure of longitudinal connectivity for stream networks

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