Landscape resistance to movement of the poison frog, <i><scp>O</scp>ophaga pumilio</i>, in the lowlands of northeastern <scp>C</scp>osta <scp>R</scp>ica

Nowakowski, A. Justin; Jiménez, Braulio D.; Allen, Michael; Diaz‐Escobar, M.; Donnelly, Maureen A.

doi:10.1111/j.1469-1795.2012.00585.x

Cited by 49 publications

(43 citation statements)

References 54 publications

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“…total basal area, biomass and canopy closure) in forest is not strongly influenced by edge proximity in this system (Nowakowski et al 2013, Schedlbauer et al 2007). To select study trees at each site, we demarcated forest-pasture edges, 100-150 m in length.…”

Section: Sampling Methodsmentioning

confidence: 84%

“…The study area has a mean annual temperature of 25 ºC and an annual precipitation of ß4 m (Sanford et al 1994). There is still moderate cover of fragmented forest (c. 50% of the landscape), and nearest-neighbour distances between forest patches are typically ࣘ200 m (Nowakowski et al 2013). There is still moderate cover of fragmented forest (c. 50% of the landscape), and nearest-neighbour distances between forest patches are typically ࣘ200 m (Nowakowski et al 2013).…”

Section: Study Area and Speciesmentioning

confidence: 99%

“…Email: anowa001@fiu.edu In north-eastern Costa Rica, the establishment of cattle pastures was the primary driver of deforestation during the previous three decades (Butterfield 1994). Pastures are characterized by extensive cover of grasses that inhibit the recruitment of woody plants, and by microclimates that are warmer and drier than in forest (Nowakowski et al 2013, Slocum 2001. If pastures represent poor-quality habitat for amphibians, populations in pastures may act as sinks, may be dominated by subordinate individuals, and could experience greater fitness costs than individuals in nearby forest, such as increased parasite loads and reduced growth and survival (Hitchings & Beebee 1997, McKenzie 2007.…”

Section: Introductionmentioning

confidence: 99%

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The value of remnant trees in pastures for a neotropical poison frog

et al. 2013

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Conversion of natural habitats to anthropogenic land uses is a primary cause of amphibian declines in species-rich tropical regions. However, agricultural lands are frequently used by a subset of forest-associated species, and the habitat value of a given land use is likely modified by the presence and characteristics of remnant trees. Here we used mark-recapture methods to examine abundances and movement probability of the poison frog, Oophaga pumilio, at individual trees in forest-fragment edges and adjacent pastures in north-eastern Costa Rica. One hundred and forty-seven trees were surveyed at three replicate sites that each included a forest fragment and adjacent pasture. Trees were sampled at distances of ࣘ30 m into forest and ࣘ150 m into pastures for Oophaga pumilio, and local environmental characteristics were measured at each tree. We also measured indices of physical condition (size and endurance) of frogs captured in forest edges and in nearby pastures. Analyses of 167 marked individuals showed no difference in per-tree abundances or sex ratios between pasture and forest edges. We found significant interactions between habitat type and leaf-litter cover, tree dbh and number of logs, indicating greater influence of local variables on abundances in pastures. Movement among trees was infrequent and not predicted by sex, size, habitat type or environmental variables. While results of endurance tests did not differ for individuals from the two habitats, frogs captured in pastures were, on average, larger than frogs captured in forest edges. These data indicate that remnant trees are important habitat features for O. pumilio in pastures and corroborate research in other systems that suggests that large relictual trees should be retained to maximize the potential for altered landscapes to provide habitat for native species.

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Section: Sampling Methodsmentioning

confidence: 84%

Section: Study Area and Speciesmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

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The value of remnant trees in pastures for a neotropical poison frog

et al. 2013

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“…2(a). This argument is likely to be particularly relevant in the case of Oophaga poison frogs, given the limited dispersal capacity of amphibians (Pyron & Wiens, 2013) and the lower levels of vagility when compared with other taxa (a mark-recapture study in O. pumilio showed that 70% of the recaptured individuals were found < 20 m from the marking site) (Nowakowski et al, 2013). decreased with increasing depth in the species tree, a pattern that is consistent with a predominance of sympatric/parapatric speciation within Central American and South American clades.…”

Section: Geographical Correlates Of Linage Diversification In the Oopmentioning

confidence: 99%

Complex niche divergence underlies lineage diversification in Oophaga poison frogs

Posso-Terranova

Andrés

2016

Journal of Biogeography

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Aim Despite the incredible diversity of lowland tropical rain forests, we still have limited understanding of the drivers of speciation in these ecoregions. Here, we investigated the relative contribution of geographical and environmental factors to the diversification of a Neotropical genus of poison frogs (Oophaga). Location Central and South America, including regions from southern Nicaragua to northern Ecuador. Methods We generated gene genealogies (12S, 16S, COI, CytB and tRNA‐val, SIAH1, H3 and Rag1) and used species phylogenetic methods (MDC and *beast) to generate a robust phylogeny of Oophaga frogs. Then, we combined the resulting phylogenetic hypothesis with detailed geographical data and environmental niche modelling (ENM) to test the role of geographical isolation, climatic niche divergence and altitudinal gradients. Results Gene genealogies were discordant and did not show exclusive genealogical patterns; however, species tree resolved the phylogenetic relationship among Oophaga species with strong node support (> 0.9 ML/BPP). Geographical ranges showed little overlap between distantly related species. However, within the South American and Central American clades, sister taxa showed substantially overlapping ranges. Analyses of ecological disparity (DTT) indicated a departure from a neutral (Brownian) model of evolution, and age‐range correlations, predicted niche occupancy profiles, and Seeva analyses showed that different species tend to evolve under different potential climatic niches. Main conclusions Oophaga frogs originated in Central America and reached South America after the closure of the Panama Isthmus. The South‐ and Central‐American clades of this genus have convergently evolved to similar patterns of geographical distribution and niche occupancy. Within clades, sister taxa showed parapatric distributions replacing each other along elevational gradients as predicted by the models of divergence along continuous ecological gradients. Accordingly, we found strong shifts in climatic niches throughout the history of these two clades. However, the largest niche shifts seem to post‐date the final elevation of the Talamanca and northern Andes. Overall, our data suggest that speciation along climatic gradients on a structured landscape has been a major evolutionary force behind the diversification of Oophaga poison frogs.

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“…Field observations and prior validation of resistance models using an independent abundance data set suggested that cost surfaces derived from species responses to microclimate would be important predictors of landscape genetic structure (Nowakowski et al . , In Press). Fourth, we determined whether the strength of landscape genetic correlations varied across time using land‐cover maps from three different time periods.…”

Section: Introductionmentioning

confidence: 99%

Mechanistic insights into landscape genetic structure of two tropical amphibians using field‐derived resistance surfaces

et al. 2015

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Conversion of forests to agriculture often fragments distributions of forest species and can disrupt gene flow. We examined effects of prevalent land uses on genetic connectivity of two amphibian species in northeastern Costa Rica. We incorporated data from field surveys and experiments to develop resistance surfaces that represent local mechanisms hypothesized to modify dispersal success of amphibians, such as habitat-specific predation and desiccation risk. Because time lags can exist between forest conversion and genetic responses, we evaluated landscape effects using land-cover data from different time periods. Populations of both species were structured at similar spatial scales but exhibited differing responses to landscape features. Litter frog population differentiation was significantly related to landscape resistances estimated from abundance and experiment data. Model support was highest for experiment-derived surfaces that represented responses to microclimate variation. Litter frog genetic variation was best explained by contemporary landscape configuration, indicating rapid population response to land-use change. Poison frog genetic structure was strongly associated with geographic isolation, which explained up to 45% of genetic variation, and long-standing barriers, such as rivers and mountains. However, there was also partial support for abundance- and microclimate response-derived resistances. Differences in species responses to landscape features may be explained by overriding effects of population size on patterns of differentiation for poison frogs, but not litter frogs. In addition, pastures are likely semi-permeable to poison frog gene flow because the species is known to use pastures when remnant vegetation is present, but litter frogs do not. Ongoing reforestation efforts will probably increase connectivity in the region by increasing tree cover and reducing area of pastures.

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Landscape resistance to movement of the poison frog, Oophaga pumilio, in the lowlands of northeastern Costa Rica

Cited by 49 publications

References 54 publications

The value of remnant trees in pastures for a neotropical poison frog

The value of remnant trees in pastures for a neotropical poison frog

Complex niche divergence underlies lineage diversification in Oophaga poison frogs

Mechanistic insights into landscape genetic structure of two tropical amphibians using field‐derived resistance surfaces

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