Spatial occupancy models applied to atlas data show Southern Ground Hornbills strongly depend on protected areas

Broms, Kristin; Johnson, Devin S.; Altwegg, Res; Conquest, Loveday L.

doi:10.1890/12-2151.1

Cited by 47 publications

(46 citation statements)

References 29 publications

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“…Our approach differs in that we consider the effects of all extant patches in the patch network according to an estimated dispersal kernel in continuous space (see also Risk et al 2011), which allows connectivity to be estimated and predicted across the entire landscape. The major difference here is that, unlike the more phenomenological conditional autoregressive (CAR) or autologistic models that represent implicit processes (Bled et al 2011, Broms et al 2014, we are able to model metapopulation (or patch occupancy) dynamics using an explicit process model, a model of dispersal, which could be further generalized for example through introduction of stage-, age-, or group-specific dispersal coefficients. Dispersal is arguably the most fundamental process driving spatial dynamics in fragmented populations (Hanski and Gaggiotti 2004); our model allows population stage structure and abundance to be considered explicitly when estimating dispersal rates and distances and provides an important tool for investigating the causes and consequence of dispersal (Clobert et al 2004).…”

Section: Discussionmentioning

confidence: 99%

A demographic, spatially explicit patch occupancy model of metapopulation dynamics and persistence

Sutherland

Elston

Lambin

2014

Ecology

121

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Abstract. Patch occupancy models are extremely important and popular tools for understanding the dynamics, and predicting the persistence, of spatially structured populations. Typically this endeavor is facilitated either by models from classic metapopulation theory focused on spatially explicit, dispersal-driven colonization-extinction dynamics and generally assuming perfect detection, or by more recent hierarchical site occupancy models that account for imperfect detection but rarely include spatial effects, such as dispersal, explicitly. Neither approach explicitly considers local demographics in a way that can be used for future projections. However, despite being arguably of equal importance, dispersal and connectivity, local demography, and imperfect detection are rarely modeled explicitly and simultaneously. Understanding the spatiotemporal occurrence patterns of spatially structured populations and making biologically realistic long-term predictions of persistence would benefit from the simultaneous treatment of space, demography, and detectability. We integrated these key ideas in a tractable and intuitive way to develop a demographic and spatially realistic patch occupancy model that incorporates components of dispersal, local demographic stage-structure, and detectability. By explicitly relating stage-specific abundances to measurable patch properties, biologically realistic projections of long-term metapopulation dynamics could be made. We applied our model to data from a naturally fragmented population of water voles Arvicola amphibius to describe observed patch occupancy dynamics and to investigate long-term persistence under scenarios of elevated stage-specific local extinction. Accounting for biases induced by imperfect detection, we were able to estimate: stable, and higher than observed metapopulation occupancy; high rates of patch turnover and stage-specific colonization and extinction rates ( juvenile and adult, respectively); and juvenile dispersal distances (average 2.10 km). We found that metapopulation persistence in the presence of elevated extinction risk differed depending on which life stage was exposed, and was more sensitive to elevated juvenile rather than adult extinction risk. Predictions of persistence when dynamics are stage-specific suggest that metapopulations may be more resilient to changes in the environment than predicted when relationships are based on patch size approximations rather than population sizes. Our approach allows explicit consideration of local dynamics and dispersal in spatially structured and stage-structured populations, provides a more detailed mechanistic understanding of metapopulation functioning, and can be used to investigate future extinction risk under biologically meaningful scenarios.

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Section: Discussionmentioning

confidence: 99%

A demographic, spatially explicit patch occupancy model of metapopulation dynamics and persistence

Sutherland

Elston

Lambin

2014

Ecology

121

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“…Any taxa with sufficient, reliable, detectability and sampling density are viable candidates for LLA, for example, amphibians (especially frogs), Lepidoptera and Odonata. More complex analytical techniques, such as occupancy modelling, can also be applied where sufficient list data occurs (e.g., Broms et al, 2013).…”

Section: Advantages Of Lla For Impact Evaluationmentioning

confidence: 99%

Evaluating protected area effectiveness using bird lists in the Australian Wet Tropics

Barnes

Szabo

Morris

et al. 2014

Diversity and Distributions

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Aim Protected areas underpin many global conservation efforts. However, it is often unclear whether they are effective in maintaining their biodiversity values, both absolutely, and also relative to other conservation actions or land uses. Longitudinal population data are critical for determining protected area performance robustly, but such data are rare. As such, there is often insufficient information with which to make adequate, informed decisions for policy and management. Conversely, informally collected data, such as species lists, are common, especially for birds, and they are often the only source of historical data. The aim of this study was to use list data to evaluate the contribution of protected areas to the conservation of endemic birds.Location Wet Tropics bioregion of Queensland, Australia.Methods We used a list-length analysis (LLA), a recently developed approach. We estimate trends in species populations with a Bayesian logistic regression to infer bird presence from non-standardized volunteer-collected bird surveys from the New Atlas of Australian Birds that were conducted both inside and outside protected areas.Results Overall, the prevalence of the majority of wet tropics endemics (18 of 21) has been stable since 1998. Sixteen species were more likely to be found within protected areas, two were more likely to be recorded outside, and three showed little difference. However, there was no difference in trends in prevalence between protected and unprotected areas for all but one endemic species.Main conclusions Where formal data collection is too expensive or time consuming, it may still be possible to inform decision-making when citizen-collected species list data are available. In the Wet Tropics, our results suggest that for the majority of the species, protected areas may contain better habitat than unprotected areas, but that birds inside protected areas are not significantly better off through time than birds outside protected areas, as long as forest outside protected areas remains intact.

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“…We used the hierarchical spatial occupancy model approach of Johnson et al () because it is effective over large spatial extents, employs a probit mixture framework that resolves issues with multicollinearity and spatial confounding, and improves algorithm convergence. We followed the model‐fitting process described in Broms et al () and first identified supported likelihood‐based occupancy models and then used a hierarchical Bayesian approach to fit the supported models with and without spatial autocorrelation.…”

Section: Methodsmentioning

confidence: 99%

“…We ran each model with 1 chain for 60,000 iterations, discarding the first 10,000 as burn‐in, and employed a thinning rate of 1/5, for a total sample of 10,000 iterations per model (after Broms et al ). The Moran cut used in the spatial model was 10% of the number of sites, and the priors for the spatial component of the model were τ ∼ γ (0.5, 0.0005; after Broms et al ). We estimated median

β s

and 95% credible intervals from the stocc models.…”

Section: Methodsmentioning

confidence: 99%

Site occupancy of brown-headed nuthatches varies with habitat restoration and range-limit context

2015

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Knowledge about species’ responses to habitat restoration can inform subsequent management and reintroduction planning. We used repeated call‐response surveys to study brown‐headed nuthatch (Sitta pusilla) patch occupancy at the current limits of its apparently expanding range in an area with active habitat restoration. We fit a probit occupancy model that accounted for spatial autocorrelation using restricted spatial regression. Nuthatch occupancy was related to patch‐level vegetation structure and range‐extension context, i.e., latitude, but not prescribed fire history. Latitude and percent tree stocking had a negative relationship with occupancy (coefficients and 95% credible intervals: −1.07 [CI: −1.63, −0.67] and −0.63 [CI: −0.97, −0.350]). The density of recently killed and well‐decayed snags had positive associations with occupancy (coefficients and 95% credible intervals: 0.57 [CI: 0.17, 1.16] and 0.37 [CI: 0.05, 0.72]). Neither grassy herbaceous cover nor percent of stocking in pine were associated with occupancy. We found that restoration efforts created suitable stand structure for brown‐headed nuthatches, but many restored sites in the range‐extension zone appeared to be vacant. Occupied habitats in the range‐extension zone had fewer snags, less frequent fire, and more shrub cover than occupied sites where the species was established. Release from conspecific competition may have permitted nuthatches in the range‐extension zone to exploit habitats that would otherwise have been marginal. Alternatively, nuthatches may be restricted to such sites although there are more suitable sites tens of kilometers away. Experimental translocations and reintroductions could determine how habitat structure and nuthatch density affect the quality of restored sites in the range‐extension zone and enable those sites to achieve their biodiversity potential. Published 2015. This article is a U.S. Government work and is in the public domain in the USA.

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Spatial occupancy models applied to atlas data show Southern Ground Hornbills strongly depend on protected areas

Cited by 47 publications

References 29 publications

A demographic, spatially explicit patch occupancy model of metapopulation dynamics and persistence

A demographic, spatially explicit patch occupancy model of metapopulation dynamics and persistence

Evaluating protected area effectiveness using bird lists in the Australian Wet Tropics

Site occupancy of brown-headed nuthatches varies with habitat restoration and range-limit context

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