Effects of natural and anthropogenic features on functional connectivity of anurans: a review of landscape genetics studies in temperate, subtropical and tropical species

Covarrubias, Sara; González, C.; Gutiérrez‐Rodríguez, Carla

doi:10.1111/jzo.12851

Cited by 13 publications

(7 citation statements)

References 93 publications

(108 reference statements)

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“…In the case of pool‐breeding amphibians, genetic connectivity implies that movement between breeding pools and breeding among individuals from different pools is sufficient to maintain genetic diversity (Frei et al 2016, Wang and Shaffer 2017, Covarrubias et al 2021). Demographic connectivity similarly implies that enough individuals move between pools to promote persistence of metapopulations, either through recolonization of breeding pools that become extirpated or through dispersal of individuals from source populations to rescue sink populations from extirpation (Semlitsch 2008, Muths et al 2018, Bailey and Muths 2019).…”

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confidence: 99%

Conservation Implications of Spatiotemporal Variation in the Terrestrial Ecology of Western Spadefoots

et al. 2021

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Conservation of species reliant on ephemeral resources can be especially challenging in the face of a changing climate. Western spadefoots (Spea hammondii) are small burrowing anurans that breed in ephemeral pools, but adults spend the majority of their lives underground in adjacent terrestrial habitat. Western spadefoots are of conservation concern throughout their range because of habitat loss, but little is known about the activity patterns and ecology of their terrestrial life stage. We conducted a radio-telemetry study of adult western spadefoots at 2 sites in southern California, USA, from December 2018 to November 2019 to characterize their survival, behavior, and movements from breeding through aestivation to refine conservation and management for the species. Western spadefoot survival varied seasonally, with risk of mortality higher in the active season than during aestivation. The probability of movement between successive observations was higher during the winter and spring and when atmospheric moisture was high and soil water content at 10-cm depth was low. The amount of rain between observations had the strongest effect on the probability of movement between observations; for every 20 mm of rainfall between observations, western spadefoots were 2.4 times more likely to move. When movements occurred, movement rates were highest when both relative humidity and soil water content at 10-cm depth were high. The conditions under which western spadefoots were likely active on the surface, likely to have moved, and moved at the highest rates are conditions that reduce the risk of desiccation of surface-active spadefoots. Western spadefoot home range areas varied between study sites and were mostly <1 ha, although 1 individual's home range area was >6 ha. Western spadefoots rapidly dispersed from the breeding pools, and asymptotic distances from the breeding pool were generally reached by June. The asymptotic distance from the breeding pool varied between sites, with the 95th percentile of the posterior predictive distribution reaching 486 m at 1 site and 187 m at the other. Western spadefoots did not select most habitat components disproportionately to their availability, but at Crystal Cove State Park, they avoided most evaluated vegetation types (graminoids, forbs, and shrubs). Spatial variation was evident in most evaluated western spadefoot behaviors; context-dependent behavior suggests that site-specific management is likely necessary for western spadefoots. Furthermore, comparison with an earlier study of western spadefoots at Crystal Cove State Park indicated substantial temporal variationThis is an open access article under the terms of the Creative Commons Attribution-NonCommercial-NoDerivs License, which permits use and distribution in any medium, provided the original work is properly cited, the use is non-commercial and no modifications or adaptations are made.

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confidence: 99%

Conservation Implications of Spatiotemporal Variation in the Terrestrial Ecology of Western Spadefoots

et al. 2021

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“…In our study, at the landscape scale there was a very low proportion cover of urban land within a 500-m radius of waterbodies (mean 0.018, SD 0.051) with few obvious artificial barriers to amphibian dispersal, although the main river channel comprised a significant natural barrier (see Covarrubias et al, 2021). There was a high proportion of forest cover surrounding waterbodies (mean 0.735, SD 0.247) which is generally favourable for amphibian movement (Joly, 2019).…”

Section: Landscape Composition and Metacommunity Theorymentioning

confidence: 72%

Hydrology is a major influence on amphibian abundance in a large European floodplain

et al. 2023

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River–floodplain ecosystems play a crucial role in connecting landscape patches through hydrological connectivity, but they are among the most threatened ecosystems. Floodplains provide important habitat for amphibians by connecting aquatic and terrestrial habitats. Modifications to floodplain hydrology can impact amphibian communities, yet few studies have examined amphibian metacommunities in floodplain wetlands. In this study, we assessed patterns in amphibian breeding abundance in one of the largest floodplains of the Danube River, Hungary, relative to hydrological connectivity and multi‐scale variables at 30 waterbody sites. Our aim was to determine whether these patterns aligned with the pond‐permanence gradient hypothesis, where breeding amphibian abundance is predicted to be highest in ephemeral ponds without large predatory fish. We used Bayesian hierarchical modelling to estimate multi‐species abundance from repeated survey (count) data collected over one breeding season. We detected the eggs and larvae of four amphibian species. The best model of abundance included covariates describing two principal component axes associated with waterbody hydrology and landscape composition within a 500‐m radius of a site. There was a positive relationship between mean community abundance at a site and hydrological disconnection from the main river channel; however, the common toad (Bufo bufo) was associated with hydrologically connected waterbodies. There was a positive relationship between mean community abundance and a high proportion of forest cover and low cover of agricultural land within a 500‐m radius around a site, although this relationship was clear for only two species. There was no support for models containing the number of large predatory fish species detected at a site. Although our results showed that amphibian abundance declined with hydrological connectivity, based on model selection we could not ascribe this relationship to an increased number of large predatory fish species detected in waterbodies close to the main river channel. Differences in life history and habitat requirements are likely to have explained interspecific responses to hydrological connectivity. Our results underscore the importance of addressing amphibian abundance at multiple spatial scales in floodplain wetlands, as landscape composition partly explained patterns in abundance. Application of multi‐species abundance modelling allowed us to investigate environmental relationships for common and infrequently detected species. Habitat restoration programmes in floodplains should provide waterbodies disconnected from main river channels as potential amphibian breeding sites and protect or restore forest as terrestrial habitat.

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“…Unexpectedly, crop fields were not assigned a very high cost to newt movement in our study. Crop fields have often been found to correlate negatively with landscape connectivity in amphibians (Covarrubias et al., 2021 ) but see Frei et al. ( 2016 ) and Goldberg and Waits ( 2010 ).…”

Section: Discussionmentioning

confidence: 99%

“…to correlate negatively with landscape connectivity in amphibians (Covarrubias et al, 2021) but see Frei et al (2016) and Goldberg and Waits (2010). For great crested newts crop fields entail lower habitat suitability when present within the local habitat (Rannap et al, 2012).…”

Section: Microclimate Land Cover Soil Ph and Landscape Resistancementioning

confidence: 97%

Genetic diversity, gene flow, and landscape resistance in a pond‐breeding amphibian in agricultural and natural forested landscapes in Norway

Haugen,

Dervo,

Østbye

et al. 2023

Evolutionary Applications

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Genetic diversity is a key part of biodiversity, threatened by human activities that lead to loss of gene flow and reduction of effective population sizes. Gene flow is a result of both landscape connectivity and demographic processes determining the number of dispersing individuals in space and time. Thus, the effect of human impact on processes determining the level of genetic diversity must be interpreted in the context of basic ecological conditions affecting survival and recruitment. When the intensity of human impact and habitat suitability correlate, the effect on genetic diversity and gene flow may be challenging to predict. We compared genetic diversity, gene flow and landscape resistance in two contrasting landscapes in Norway for the pond‐breeding amphibian Triturus cristatus: a highly human‐impacted, agricultural landscape with ecologically productive habitats, and a forested landscape with less productive habitats and lower levels of human impact. Our results show that genetic diversity was higher and gene flow lower within the forested landscape. Microclimatic moisture conditions and vegetation cover were important determinants of landscape resistance to gene flow within both landscapes. There were indications that landscape resistance was increased by minor roads in the forested landscape, which was not the case for the agricultural landscape, suggesting a higher vulnerability to human interference within the landscape matrix for the populations in less productive habitats. Our findings suggest that the effect of human impact on genetic diversity may not be straightforward but modulated by the ecological conditions underlying local demographic processes. Populations within both landscapes seem to be vulnerable to loss of genetic diversity, but due to different mechanisms. This has implications for the choice of relevant management actions, that is, increasing population stability may be more relevant within an agricultural landscape still permeable for dispersal, while conserving dispersal corridors may be more appropriate in the forested landscape, to avoid isolation and increased genetic drift.

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Effects of natural and anthropogenic features on functional connectivity of anurans: a review of landscape genetics studies in temperate, subtropical and tropical species

Cited by 13 publications

References 93 publications

Conservation Implications of Spatiotemporal Variation in the Terrestrial Ecology of Western Spadefoots

Conservation Implications of Spatiotemporal Variation in the Terrestrial Ecology of Western Spadefoots

Hydrology is a major influence on amphibian abundance in a large European floodplain

Genetic diversity, gene flow, and landscape resistance in a pond‐breeding amphibian in agricultural and natural forested landscapes in Norway

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