Browsing by Autor "Carsten Nowak"

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Accuracy, limitations and cost efficiency of eDNA‐based community survey in tropical frogs
(Wiley, 2018) Miklós Bálint; Carsten Nowak; Orsolya Márton; Steffen U. Pauls; Claudia Wittwer; José Luis Aramayo; Arne Schulze; Thierry Chambert; Berardino Cocchiararo; Martin Jansen
Rapid environmental change in highly biodiverse tropical regions demands efficient biomonitoring programmes. While existing metrics of species diversity and community composition rely on encounter-based survey data, eDNA recently emerged as alternative approach. Costs and ecological value of eDNA-based methods have rarely been evaluated in tropical regions, where high species richness is accompanied by high functional diversity (e.g., the use of different microhabitats by different species and life stages). We first tested whether estimation of tropical frogs' community structure derived from eDNA data is compatible with expert field assessments. Next, we evaluated whether eDNA is a financially viable solution for biodiversity monitoring in tropical regions. We applied eDNA metabarcoding to investigate frog species occurrence in five ponds in the Chiquitano dry forest region in Bolivia and compared our data with a simultaneous visual and audio encounter survey (VAES). We found that taxon lists and community structure generated with eDNA and VAES correspond closely, and most deviations are attributable to different species' life histories. Cost efficiency of eDNA surveys was mostly influenced by the richness of local fauna and the number of surveyed sites: VAES may be less costly in low-diversity regions, but eDNA quickly becomes more cost-efficient in high-diversity regions with many sites sampled. The results highlight that eDNA is suitable for large-scale biodiversity surveys in high-diversity areas if life history is considered, and certain precautions in sampling, genetic analyses and data interpretation are taken. We anticipate that spatially extensive, standardized eDNA biodiversity surveys will quickly emerge in the future.
Accuracy, limitations and cost-efficiency of eDNA-based community survey in tropical frogs
(2017) Miklós Bálint; Carsten Nowak; Orsolya Márton; Steffen U. Pauls; Claudia Wittwer; B. Jose Luis Aramayo; Arne Schulze; Thierry Chambert; Berardino Cocchiararo; Martin Jansen
Abstract Rapid environmental change in highly biodiverse tropical regions demands efficient biomonitoring programs. While existing metrics of species diversity and community composition rely on encounter-based survey data, eDNA recently emerged as alternative approach. Costs and ecological value of eDNA-based methods have rarely been evaluated in tropical regions, where high species richness is accompanied by high functional diversity (e.g. the use of different microhabitats by different species and life-stages). We first tested whether estimation of tropical frogs’ community structure derived from eDNA data is compatible with expert field assessments. Next we evaluated whether eDNA is a financially viable solution for biodiversity monitoring in tropical regions. We applied eDNA metabarcoding to investigate frog species occurrence in five ponds in the Chiquitano dry forest region in Bolivia and compared our data with a simultaneous visual and audio encounter survey (VAES). We found that taxon lists and community structure generated with eDNA and VAES correspond closely, and most deviations are attributable to different species’ life histories. Cost efficiency of eDNA surveys was mostly influenced by the richness of local fauna and the number of surveyed sites: VAES may be less costly in low-diversity regions, but eDNA quickly becomes more cost-efficient in high-diversity regions with many sites sampled. The results highlight that eDNA is suitable for large-scale biodiversity surveys in high-diversity areas if life history is considered, and certain precautions in sampling, genetic analyses and data interpretation are taken. We anticipate that spatially extensive, standardized eDNA biodiversity surveys will quickly emerge in the future.
Twenty-five species of frogs in a liter of water: eDNA survey for exploring tropical frog diversity
(2017) Miklós Bálint; Carsten Nowak; Orsolya Márton; Steffen U. Pauls; Claudia Wittwer; José Luis Aramayo; Arne Schulze; Thierry Chambert; Berardino Cocchiararo; Martin Jansen
Biodiversity is declining at unprecedented rates, with species extinctions being an important component of this process. Currently it is almost impossible to evaluate this loss since biodiversity data is lacking even for emblematic species. Recent advances in eDNA marker gene studies promise to deliver the necessary data, but these approaches have almost never been evaluated in the tropics. Here we evaluate whether 1) eDNA metabarcoding may reliably generate frog faunistic data in species-rich tropical areas, 2) the ecological signal in eDNA data is compatible with data from visual and audio encounter survey (VAES), and 3) eDNA data represent a financially viable solution to biodiversity data acquisition. We applied eDNA metabarcoding to investigate frog species occurrence in five ponds in the Chiquitano dry forest region in Bolivia and compared our data with a simultaneous VAES. We find that taxon lists generated with eDNA and VAES correspond closely, and most deviations are attributable to different species' life histories. The ecological signal in eDNA closely matches the signal from VAES. We find that the cost efficiency of eDNA surveys is mostly influenced by the richness of local fauna and the number of surveyed sites: VAES may be less costly in low-diversity regions, but eDNA quickly becomes more cost-efficient in high-diversity regions, particularly with many sites. The results underline that eDNA is suitable for large-scale biodiversity surveys in high-diversity areas if precautions in data generation and interpretation are taken and this projects spatially extensive standardized biodiversity surveys in the close future.