Extracting useful data from imperfect monitoring schemes: endangered butterflies at San Bruno Mountain, San Mateo County, California (1982–2000) and implications for habitat management

Longcore, Travis; Lam, Christine S.; Kobernus, Patrick; Polk, Eben; Wilson, John P.

doi:10.1007/s10841-010-9263-9

Cited by 17 publications

(13 citation statements)

References 25 publications

(28 reference statements)

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“…Researchers have a suite of methods at their disposal to estimate animal abundance and a number of these methods have been applied to butterflies (Pollard & Yates, ; Brown & Boyce, ; Barton & Bach, ; Powell et al ., ; Haddad et al ., ; Longcore et al ., ; Isaac et al ., ; Pellet et al ., ). The choice of which method to use involves weighing a series of trade‐offs involving: speed (which relates to financial cost), precision, and bias (Williams et al ., ; Haddad et al ., ).…”

Section: Introductionmentioning

confidence: 99%

“…Researchers have a suite of methods at their disposal to estimate animal abundance and a number of these methods have been applied to butterflies (Pollard & Yates, 1993;Brown & Boyce, 1998;Barton & Bach, 2005;Powell et al, 2007;Haddad et al, 2008;Longcore et al, 2010; Correspondence: Christopher A. Hamm, Department of Ecology and Evolution, University of California at Davis, One Shields Avenue, Davis, California 95616, USA. E-mail: cahamm@ ucdavis.edu Isaac et al, 2011;Pellet et al, 2012).…”

Section: Introductionmentioning

confidence: 99%

“…The choice of which method to use involves weighing a series of trade-offs involving: speed (which relates to financial cost), precision, and bias (Williams et al, 2002;Haddad et al, 2008). Timed-meander (TM) or 'wandering transect' surveys (in which small groups of surveyors meander through potential habitat and record the number of target organisms encountered) are efficient and may illuminate changes in occupancy patterns, but cannot estimate demographic parameters such as abundance (Longcore et al, 2010). Pollard-Yates (PY) transects are standardised, efficient (small groups of surveyors move quickly along pre-established transects), and allow for estimation of demographic parameters, but make assumptions concerning detectability and habitat homogeneity that may not always be justified (Pollard & Yates, 1993;Haddad et al, 2008;Nowicki et al, 2008;Isaac et al, 2011;Pellet et al, 2012).…”

Section: Introductionmentioning

confidence: 99%

“…Mitchell's satyr population status is currently assessed using TM surveys in which small teams wander through habitat and count the number of N. m. mitchellii observed (Barton, 2008a). These surveys reported the number of butterflies observed during visits and may be used to monitor occupancy (Longcore et al, 2010). Although this method is efficient (workers can traverse most sites in approximately 3 h), the data generated from it cannot be extrapolated into estimates of abundance.…”

Section: Introductionmentioning

confidence: 99%

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Estimating abundance of the federally endangeredMitchell's satyr butterfly using hierarchical distance sampling

Hamm

2013

Insect Conserv Diversity

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Estimates of animal abundance are essential to conservation biology and are sorely lacking for many endangered species in the United States of America. This lack of knowledge may disproportionately affect butterflies in the USA, which form the largest group of federally protected insects (20 of 62 species). The Mitchell's satyr butterfly, Neonympha mitchellii mitchellii, is a federally endangered species found at 18 highly isolated sites in the Eastern USA. Currently, surveys are conducted by meandering through habitat and recording the number of butterflies observed. These surveys are efficient in terms of staffing and time, but the data from these surveys cannot be used to estimate abundance. Mark release recapture surveys generate estimates of demographic parameters and have been conducted, albeit infrequently, and require high staffing levels and weeks of fieldwork to generate estimates with reasonable error. I employed hierarchical distance sampling along line transects to estimate N. m. mitchellii abundance at one site in lower Michigan, USA. This method requires one observer to traverse a series of transects at a walking pace and record the number of butterflies observed and their perpendicular distance to the transect line. My results suggest that this method is as cost efficient as meander surveys, but generates reasonable estimates of butterfly abundance.

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Section: Introductionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

See 2 more Smart Citations

Estimating abundance of the federally endangeredMitchell's satyr butterfly using hierarchical distance sampling

Hamm

2013

Insect Conserv Diversity

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“…In conservation, occupancy is typically regarded as inferior to abundance because it does not provide early warning of population declines (Pollock 2006;Joseph et al 2006). However, by assuming that a species' detectability is largely a function of its abundance, and recognizing that change in population size typically accompanies change in proportion of area occupied Longcore et al 2010), it is possible to reliably estimate abundance and population trend from occupancy data (He and Gaston 2000;Royle and Nichols 2003;Pollock 2006;Zhou and Griffiths 2007;Hui et al 2009;Hwang and He 2011;but see Strayer 1999). Detection/non-detection data tend to approximate patch-level processes with far less effort than abundance surveys (MacKenzie et al 2003;Zhou and Griffiths 2007), and may provide the best information under limited resources.…”

Section: Introductionmentioning

confidence: 99%

Optimal design of butterfly occupancy surveys and testing if occupancy converts to abundance for sparse populations

Bried¹,

Pellet²

2011

J Insect Conserv

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Occupancy has several important advantages over abundance methods and may be the best choice for monitoring sparse populations. Here we use simulations to evaluate competing designs (number of sites vs. number of surveys) for occupancy monitoring, with emphasis on sparse populations of the endangered Karner blue butterfly (Lycaeides melissa samuelis Nabokov). Because conservation planning is usually abundance-based, we also ask whether detection/non-detection data may reliably convert to abundance, hypothesizing that occupancy provides a more dependable shortcut when populations are sparse. Count-index and distance sampling were conducted across 50 habitat patches containing variably sparse Karner blue populations. We used occupancy-detection model estimates as simulation inputs to evaluate primary replication tradeoffs, and used peak counts and population densities to evaluate the occupancy-abundance relationship. Detection probability and therefore optimal design of occupancy monitoring was strongly temperature dependent. Assuming a quality threshold of 0.075 root-mean square error for the occupancy estimator, the minimum allowable effort was 360 (40 sites 9 9 surveys) for spring generation and 200 (20 sites 9 10 surveys) for summer generation. A mixture model abundance estimator for repeated detection/nondetection data was biased low for high-density and lowdensity populations, suggesting that occupancy may not provide a reliable shortcut in abundance-based conservation planning for sparse butterfly populations.

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Making sense of wildlife habitat use on active oil sands mines: Quasi‐experiments, occupancy models, trends assessments and upland habitat reclamation

Hawkes,

Gibeau,

Challenger

2024

Ecol Sol and Evidence

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Intensive resource extraction activity in the oil sands of Canada alters the quantity, structure and distribution of native ecosystems, which in turn creates substantive challenges for conservation, land management and habitat reclamation. Progressive reclamation occurs on active mine sites in the Athabasca oil sands region (AOSR) of Canada, along with concurrent assessments of reclamation effectiveness. Yet, little is known about the ability of reclaimed habitats to mitigate for the short‐ and long‐term impacts associated with open‐pit mines and provide functional habitat for wildlife. We used a robust quasi‐experiment that combined camera trap data from an observational study with an innovative occupancy model to assess the effectiveness of upland reclamation to provide habitat for wildlife in the AOSR. The dynamic occupancy models were applied to 15 years of camera trap data to assess wildlife usage patterns of nine species of wildlife over seven types of habitats. The habitats sampled ranged from mining‐disturbed habitats reclaimed to upland forest ecosites common in the region, habitats disturbed by natural (fire) and human disturbances (clear‐cut logging), with comparisons to mostly intact mature forests. Our results indicate that the nine species of wildlife assessed used habitats in a manner consistent with expectations: some preferred disturbance‐dominated habitats while others used mature forest to a higher degree. We demonstrate that the application of dynamic occupancy models to camera trap data reliably discerned these trends, providing the means to predict wildlife usage patterns in an ever‐changing landscape, including one containing bitumen extraction as a contributor to landscape‐level modifications. Practical implication: Our work illustrates how continued monitoring of wildlife using camera traps contributes to assessments of reclamation effectiveness with respect to wildlife occurrence, distribution and usage patterns in anthropogenically and naturally disturbed landscapes. Evaluating the effectiveness of reclamation is especially important given the expected increase in habitat reclamation on active oil sands mines over the next several decades, coupled with the need to ensure that disturbed habitats regain ecological function able to sustain wildlife in the future.

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Extracting useful data from imperfect monitoring schemes: endangered butterflies at San Bruno Mountain, San Mateo County, California (1982–2000) and implications for habitat management

Abstract: Managers surveyed for sensitive butterfly species in the San Bruno

Cited by 17 publications

References 25 publications

Estimating abundance of the federally endangeredMitchell's satyr butterfly using hierarchical distance sampling

Estimating abundance of the federally endangeredMitchell's satyr butterfly using hierarchical distance sampling

Optimal design of butterfly occupancy surveys and testing if occupancy converts to abundance for sparse populations

Making sense of wildlife habitat use on active oil sands mines: Quasi‐experiments, occupancy models, trends assessments and upland habitat reclamation

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