Space use, forays, and habitat selection by California Spotted Owls (Strix occidentalis occidentalis) during the breeding season: New insights from high resolution GPS tracking

Blakey, Rachel V.; Siegel, Rodney B.; Webb, Elisabeth B.; Dillingham, Colin P.; Bauer, Rachel L.; Johnson, Matthew D.; Kesler, Dylan C.

doi:10.1016/j.foreco.2018.10.017

Cited by 30 publications

(24 citation statements)

References 60 publications

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“…Our prediction that call rate would be greater in older forest was not supported, which may be due to territorial defense (i.e., bouts of 4‐note calls) occurring at the periphery of territories, rather than core areas that are positively associated with older forest habitat (Blakey et al. 2019). It may also be due to our exclusion of unoccupied sites from the analysis, because, as the occupancy models indicated, site occupancy was positively associated with older forest (Supporting Information).…”

Section: Discussionmentioning

confidence: 72%

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Using the ecological significance of animal vocalizations to improve inference in acoustic monitoring programs

Wood

Klinck

Gustafson

et al. 2020

Conservation Biology

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Recent bioacoustic advances have facilitated large‐scale population monitoring for acoustically active species. Animal sounds, however, can of information that is underutilized in typical approaches to passive acoustic monitoring (PAM) that treat sounds simply as detections. We developed 3 methods of extracting additional ecological detail from acoustic data that are applicable to a broad range of acoustically active species. We conducted landscape‐scale passive acoustic surveys of a declining owl species and an invasive congeneric competitor in California. We then used sex‐specific vocalization frequency to inform multistate occupancy models; call rates at occupied sites to characterize interactions with interspecific competitors and assess habitat quality; and a flexible multivariate approach to differentiate individuals based on vocal characteristics. The multistate occupancy models yielded novel estimates of breeding status occupancy rates that were more robust to false detections and captured known habitat associations more consistently than single‐state occupancy models agnostic to sex. Call rate was related to the presence of a competitor but not habitat quality and thus could constitute a useful behavioral metric for interactions that are challenging to detect in an occupancy framework. Quantifying multivariate distance between groups of vocalizations provided a novel quantitative means of discriminating individuals with ≥20 vocalizations and a flexible tool for balancing type I and II errors. Therefore, it appears possible to estimate site turnover and demographic rates, rather than just occupancy metrics, in PAM programs. Our methods can be applied individually or in concert and are likely generalizable to many acoustically active species. As such, they are opportunities to improve inferences from PAM data and thus benefit conservation.

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Section: Discussionmentioning

confidence: 72%

“…Only the multistate models indicated positive associations between site occupancy ( ψ sp ) and older forest, a habitat type that is important for roosting (Blakey et al. 2019), and between pair occupancy ( ψ p ) and montane riparian forest, a habitat type that is likely important for foraging (Meyer et al. 2005) (Supporting Information).…”

Section: Discussionmentioning

confidence: 99%

Using the ecological significance of animal vocalizations to improve inference in acoustic monitoring programs

Wood

Klinck

Gustafson

et al. 2020

Conservation Biology

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“…For example, spotted owls typically show high site fidelity (Forsman et al 2002;Blakesley et al 2006;Ganey et al 2014b), and resident owls may therefore continue to occupy territories immediately following fire even if the habitat within those territories is severely degraded (Ganey et al 2017). More importantly, recent data on movements of Global Positioning System-tagged California spotted owls suggest that, at least for that subspecies, occupancy rates estimated based on locations of unmarked owls may badly overestimate true occupancy rates (Berigan et al 2018;Blakey et al 2019). Further, in a long-term study involving uniquely marked northern spotted owls, Rockweit et al (2017) found that occupancy rates in severely burned territories remained relatively high over time, but survival rates in these territories were lower and turnover rates were higher than in unburned or lightly burned territories.…”

Section: Pre-and Post-fire Predicted Nesting Habitat Suitabilitymentioning

confidence: 99%

The effect of scale in quantifying fire impacts on species habitats

2020

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Background: Fire size and severity have increased in the western United States in recent decades, and are expected to continue to increase with warming climate. Habitats for many species are threatened by large and high-severity fires, but the effect of spatial scale on the relationship between fires and habitat modifications is poorly understood. We used the 2011 Wallow Fire-the largest wildfire in the state history of Arizona, USA-as a case study and assessed changes in predicted nesting habitat of the threatened Mexican spotted owl (Strix occidentalis Xántus de Vésey) in the first three years following the fire. Our objective was to explore potential relationships between burn severity and changes in habitat suitability at different spatial scales. To accomplish this, we applied a multi-scale optimized habitat selection model to pre-and post-fire landscapes and compared the differences in predictions along a continuous scale gradient. Results: Fire effects on habitat quality were spatially variable and the strength and direction of relationships were scale-dependent. Spatial patterns of burn-severity mosaic resembled the patterns of habitat suitability change. High burn severity reduced nesting habitat suitability and this relationship was strongest at broad scales. Pre-fire habitat suitability was positively related to burn severity, again at fairly broad scales, but the relationship was weak. Low-severity fires had little effect on habitat suitability. Conclusions: Multi-scale analysis may influence the statistical measures of goodness of fit in assessing fire effects on species and their habitats. Future studies should explicitly address spatial scale when quantifying fire effects.

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“…It has been shown that even low rates of false positive detections result in positive biases that inflate occupancy rate estimates (Royle and Link 2006, Miller et al 2011, Sutherland et al 2013. We also knew from GPS-tagbased studies of spotted owls that owls frequently move amongst unoccupied (and sometimes occupied) territories (Berigan et al 2018, Blakey et al 2019). Therefore, we were able to exclude false positive detections from our owl detection database because we knew which owls were present at a given historical territory owing to our observation of their colour bands, both before and after the King Fire.…”

Section: The Science Of Spotted Owls and Firementioning

confidence: 99%

Megafire effects on spotted owls: elucidation of a growing threat and a response to Hanson et al. (2018)

Jones¹,

Gutiérrez²,

Tempel³

et al. 2019

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The extent to which wildfire adversely affects spotted owls (Strixoccidentalis) is a key consideration for ecosystem restoration efforts in seasonally dry forests of the western United States. Recently, Jones et al. (2016) demonstrated that the 2014 King Fire (a “megafire”) adversely affected a population of individually-marked California spotted owls (S.o.occidentalis) monitored as part of a long-term demographic study in the Sierra Nevada, California, USA because territory occupancy declined substantially at territories burned at high-severity and GPS-tagged spotted owls avoided large patches of high-severity fire. Hanson et al. (2018) attempted to reassess changes in territory occupancy of the Jones et al. (2016) study population and claimed that occupancy declined as a result of post-fire salvage logging not fire per se and suggested that the avoidance of GPS-marked owls from areas that burned at high-severity was due to post-fire logging rather than a response to high-severity fire. Here, we demonstrate that Hanson et al. (2018) used erroneous data, inadequate statistical analyses and faulty inferences to reach their conclusion that the King Fire did not affect spotted owls and, more broadly, that large, high-severity fires do not pose risks to spotted owls in western North American dry forest ecosystems. We also provide further evidence indicating that the King Fire exerted a clear and significant negative effect on our marked study population of spotted owls. Collectively, the additional evidence presented here and in Jones et al. (2016) suggests that large, high-severity fires can pose a threat to spotted owls and that restoration of natural low- to mixed-severity frequent fire regimes would likely benefit both old-forest species and dry forest ecosystems in this era of climate change. Meeting these dual objectives of species conservation and forest restoration will be complex but it is made more challenging by faulty science that does not acknowledge the full range of wildfire effects on spotted owls.

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Space use, forays, and habitat selection by California Spotted Owls (Strix occidentalis occidentalis) during the breeding season: New insights from high resolution GPS tracking

Cited by 30 publications

References 60 publications

Using the ecological significance of animal vocalizations to improve inference in acoustic monitoring programs

Using the ecological significance of animal vocalizations to improve inference in acoustic monitoring programs

The effect of scale in quantifying fire impacts on species habitats

Megafire effects on spotted owls: elucidation of a growing threat and a response to Hanson et al. (2018)

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