Multi-level, multi-scale habitat selection by a wide-ranging, federally threatened snake

Bauder, Javan M.; Breininger, David R.; Bolt, Marvin; Legare, Michael L.; Jenkins, Christopher L.; Rothermel, Betsie B.; McGarigal, Kevin

doi:10.1007/s10980-018-0631-2

Cited by 32 publications

(53 citation statements)

References 91 publications

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“…A second feature of D. couperi life history that reduces opportunity for speciation is the variety of habitats used by these animals throughout a year (e.g., [72]), particularly in peninsular Florida, where individuals will utilize habitats with varying degrees of anthropogenic disturbance [76]. This broad habitat use reduces the opportunity for ecological barriers to gene flow and is consistent with the high rates of gene flow indicated by our microsatellite analysis.…”

Section: Discussionmentioning

confidence: 52%

Phylogenetic, population genetic, and morphological analyses reveal evidence for one species of Eastern Indigo Snake (Drymarchon couperi)

Folt

Bauder

Spear

et al. 2018

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30Accurate species delimitation and description are necessary to guide effective conservation 31 management of imperiled species. The Eastern Indigo Snake (Drymarchon couperi) is a large 32 species in North America that is federally-protected as Threatened under the Endangered Species 33 Act. Recently, two associated studies hypothesized that Drymarchon couperi is two species. 34 Here, we use diverse approaches to test the two-species hypothesis for D. couperi. Our analyses 35 reveal that (1) phylogenetic reconstruction in previous studies was based entirely on variance of 36 mitochondrial DNA sequence data, (2) microsatellite data demonstrate significant population 37 admixture and nuclear gene flow between mitochondrial lineages, and (3) morphological 38 analyses recover a single diagnosable species. Our results are inconsistent with the two-species 39 hypothesis, thus we reject it and formally place Drymarchon kolpobasileus into synonymy with 40 D. couperi. We suggest inconsistent patterns between mitochondrial and nuclear DNA may be 41 driven by high dispersal of males relative to females. We caution against species delimitation 42 exercises when one or few loci are used without evaluation of contemporary gene flow, 43 particularly species with strong sex-biased dispersal (e.g., squamates) and/or when results have 44 implications for ongoing conservation efforts. 45 46 65 Mississippi, Alabama, and the Florida panhandle [13]. 66 Current conservation management plans for D. couperi were developed under the 67 hypothesis that D. couperi represents a single species. However, this hypothesis was recently 68 challenged by Krysko et al. [15], who used DNA sequence analyses to describe two genetic 69 lineages of D. couperi -an Atlantic lineage, including populations in southeastern Georgia and 70 eastern peninsular Florida, and a Gulf lineage of populations in western and southern peninsular 71Florida and the Florida panhandle. This phylogeographic study was followed by a second paper 72 [16] that analyzed morphological variation between the Atlantic and Gulf lineages and provided 73 4 an official description of the Gulf lineage as a purported novel species, the Gulf Coast Indigo 74 Snake (Drymarchon kolpobasileus). 75 Given the conservation status of D. couperi (sensu lato), these results have potentially 76 important consequences for the conservation of Eastern Indigo Snakes. First, division of D. 77 couperi (sensu lato) into two smaller-ranged species results in two species with substantially 78 smaller population sizes that are, therefore, at greater risk of extinction (sensu [2]; e.g., [17]). 79 Second, conservation and recovery of two rare species requires more time and funds than one, 80 and both resources are in short supply. Finally, as noted by Krysko et al. [15], active 81 conservation management plans for D. couperi (sensu lato) include population repatriation 82 projects in Alabama and the Florida panhandle, where populations attributed to the Gulf lineage 83 presumably were...

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Section: Discussionmentioning

confidence: 52%

Phylogenetic, population genetic, and morphological analyses reveal evidence for one species of Eastern Indigo Snake (Drymarchon couperi)

Folt

Bauder

Spear

et al. 2018

Preprint

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“…Separate models can therefore be used to investigate differences in habitat use that manifest at lower levels between these subcategories, whilst integrating universal higher level model output (e.g. Rettie and Messier 2000;Gabor et al 2001;Bauder et al 2018). By allowing drivers operating at different scales to be disentangled, regionally suitable areas without the local-or landscape-scale features required at lower levels can be identified (Pearson et al 2004;Vicente et al 2011), improving the prescription and spatial targeting of management solutions (Lindenmayer 2000;Whittingham et al 2007;Zeller et al 2017).…”

Section: Discussionmentioning

confidence: 99%

“…(b) Post-hoc multi-level models HSI values from each single-level model were overlaid, harmonised to the finest pixel size without interpolation and multiplied on a pixel-by-pixel basis (e.g. Johnson et al 2004;Fournier et al 2017;Zeller et al 2017;Bauder et al 2018). As this approach involves using the product of the outputs from two or more models using different input data, measures of AICc and three-fold AUC could not be calculated without relying on the mean of these validation metrics across the input models, which we believe to be largely uninformative.…”

Section: Comparisons With Other Approachesmentioning

confidence: 99%

“…Distributions at higher levels are shaped by factors that vary slowly across space, such as the influence of climate on population ranges; more local scale, patchy predictors influencing a species' mobility, resource distribution or biotic interactions are important at lower levels (Pearson and Dawson 2003;Pearson et al 2004;Vicente et al 2014;Razgour et al 2014). HSMs that integrate drivers at their scale of effect across multiple levels, and that encompass the full range of conditions experienced across the population range, provide a more complete characterisation of a species' niche and prevent truncation of modelled speciesenvironment relationships (Barbet-Massin et al 2010;DeCesare et al 2012;Fournier et al 2017;Heisler et al 2017;Bauder et al 2018;Mateo et al 2019b).…”

Section: Introductionmentioning

confidence: 99%

“…(ii) Post-hoc multi-level-combinations of singlelevel, multi-scale model outputs (e.g. Johnson et al 2004;Hattab et al 2014;Fournier et al 2017;Zeller et al 2017;Bauder et al 2018).…”

Section: Introductionmentioning

confidence: 99%

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A sequential multi-level framework to improve habitat suitability modelling

et al. 2020

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Context Habitat suitability models (HSM) can improve our understanding of a species' ecology and are valuable tools for informing landscape-scale decisions. We can increase HSM predictive accuracy and derive more realistic conclusions by taking a multi-scale approach. However, this process is often statistically complex and computationally intensive. Objectives We provide an easily implemented, flexible framework for sequential multi-level, multi-scale HSM and compare it to two other commonly-applied approaches: single-level, multi-scale HSM and their post-hoc combinations. Methods Our framework implements scale optimisation and model tuning at each level in turn, from the highest (population range) to the lowest (e.g. foraging habitat) level, whilst incorporating output habitat suitability indices from a higher level as a predictor. We used MaxEnt and a species of conservation concern in Britain, the lesser horseshoe bat (Rhinolophus hipposideros), to demonstrate and compare multi-scale approaches. Results Integrating models across levels, either by applying our framework, or by multiplying singlelevel model predictions, improved predictive performance over single-level models. Moreover, differences in the importance and direction of the speciesenvironment associations highlight the potential for false inferences from single-level models or their posthoc combinations. The single-level summer range model incorrectly identified a positive influence of heathland cover, whereas sequential multi-level models made biological sense and underlined this species' requirement for extensive broadleaf woodland cover, hedgerows and access to buildings for roosting in rural areas. Conclusions We conclude that multi-level HSM appear superior to single-level, multi-scale approaches; models should be sequentially integrated across levels if information on species-environment relationships is of importance.

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Accounting for geographic variation in species‐habitat associations during habitat suitability modeling

Chandler

Jenkins²,

Bauder

2022

Ecological Applications

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Range‐wide species conservation efforts are facilitated by spatially explicit estimates of habitat suitability. However, species‐environment relationships often vary geographically and models assuming geographically constant relationships may result in misleading inferences. We present the first range‐wide habitat suitability model (HSM) for the federally threatened eastern indigo snake (Drymarchon couperi) as a case study illustrating an approach to account for known latitudinal variation in habitat associations. Specifically, we modeled habitat suitability using interactive relationships between minimum winter temperature and several a priori environmental covariates and compared our results to those from models assuming geographically constant relationships. We found that multi‐scale models including interactive effects with winter temperature outperformed single‐scale models and models not including interactive effects with winter temperature. Our top‐ranked model had suitable range‐wide predictive performance and identified numerous large (i.e., ≥1000 ha) potential habitat patches throughout the indigo snake range. Predictive performance was greatest in southern Georgia and northern Florida likely reflecting more restrictive indigo snake habitat associations in these regions. This study illustrates how modeling interactive effects between temperature and environmental covariates can improve the performance of HSMs across geographically varying environmental gradients.

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Multi-level, multi-scale habitat selection by a wide-ranging, federally threatened snake

Cited by 32 publications

References 91 publications

Phylogenetic, population genetic, and morphological analyses reveal evidence for one species of Eastern Indigo Snake (Drymarchon couperi)

Phylogenetic, population genetic, and morphological analyses reveal evidence for one species of Eastern Indigo Snake (Drymarchon couperi)

A sequential multi-level framework to improve habitat suitability modelling

Accounting for geographic variation in species‐habitat associations during habitat suitability modeling

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