scholarly journals Challenges for assessing vertebrate diversity in turbid Saharan water-bodies using environmental DNA

Genome ◽  
2018 ◽  
Vol 61 (11) ◽  
pp. 807-814 ◽  
Author(s):  
Bastian Egeter ◽  
Sara Peixoto ◽  
José C. Brito ◽  
Simon Jarman ◽  
Pamela Puppo ◽  
...  

The Sahara desert is the largest warm desert in the world and a poorly explored area. Small water-bodies occur across the desert and are crucial habitats for vertebrate biodiversity. Environmental DNA (eDNA) is a powerful tool for species detection and is being increasingly used to conduct biodiversity assessments. However, there are a number of difficulties with sampling eDNA from such turbid water-bodies and it is often not feasible to rely on electrical tools in remote desert environments. We trialled a manually powered filtering method in Mauritania, using pre-filtration to circumvent problems posed by turbid water in remote arid areas. From nine vertebrate species expected in the water-bodies, four were detected visually, two via metabarcoding, and one via both methods. Difficulties filtering turbid water led to severe constraints, limiting the sampling protocol to only one sampling point per study site, which alone may largely explain why many of the expected vertebrate species were not detected. The amplification of human DNA using general vertebrate primers is also likely to have contributed to the low number of taxa identified. Here we highlight a number of challenges that need to be overcome to successfully conduct metabarcoding eDNA studies for vertebrates in desert environments in Africa.

2021 ◽  
pp. 1-9
Author(s):  
Izabela Barata

Surveys of rare or cryptic species may miss individuals or populations that are actually present. Despite the increasing use of environmental DNA (eDNA) analysis to survey species in ponds, rivers, and lakes, very few studies have attempted to use eDNA for the detection of species using very small water bodies such as those accumulated within plants. Our aim was to investigate the feasibility of an eDNA sampling method for detecting Crossodactylodes itambe, an endemic bromeliad-dwelling frog from a remote location in Brazil. We collected water samples from 19 bromeliads for which we had observational data from direct visual surveys. We compared occupancy estimated from direct observations with the results from quantitative real-time PCR based eDNA assays. For observational surveys, we used a single season occupancy model. We applied a novel Bayesian occupancy model to estimate occupancy from eDNA samples, as well as false positives and false negatives at different stages of the workflow. eDNA from bromeliad tanks provided reliable estimates, with very low error levels and improved detection when compared to detectability from direct observation. Estimated occupancies using eDNA and visual survey methods were similar. The method is feasible for species restricted to small water bodies and exposed to direct UV radiation, and particularly useful to survey remote locations and confirm species presence. eDNA analysis provides a viable alternative to destructive sampling of bromeliads or direct observation methods that require logistically challenging repeated observations. Therefore, eDNA methods may be widely applicable to sampling programmes of other amphibians that live in plants.


Author(s):  
Natalia Kuczyńska-Kippen ◽  
Barbara Nagengast ◽  
Tomasz Joniak

The impact of biometric parameters of a hydromacrophyte habitat on the structure of zooplankton communities in various types of small water bodies


Author(s):  
Christopher Mulanda Aura ◽  
Ruth Lewo Mwarabu ◽  
Chrisphine S. Nyamweya ◽  
Horace Owiti ◽  
Collins Onyango Ongore ◽  
...  

Sensors ◽  
2021 ◽  
Vol 21 (21) ◽  
pp. 7403
Author(s):  
Pavel P Fil ◽  
Alla Yu Yurova ◽  
Alexey Dobrokhotov ◽  
Daniil Kozlov

In semi-arid ecoregions of temperate zones, focused snowmelt water infiltration in topographic depressions is a key, but imperfectly understood, groundwater recharge mechanism. Routine monitoring is precluded by the abundance of depressions. We have used remote-sensing data to construct mass balances and estimate volumes of temporary ponds in the Tambov area of Russia. First, small water bodies were automatically recognized in each of a time series of high-resolution Planet Labs images taken in April and May 2021 by object-oriented supervised classification. A training set of water pixels defined in one of the latest images using a small unmanned aerial vehicle enabled high-confidence predictions of water pixels in the earlier images (Cohen’s Κ = 0.99). A digital elevation model was used to estimate the ponds’ water volumes, which decreased with time following a negative exponential equation. The power of the exponent did not systematically depend on the pond size. With adjustment for estimates of daily Penman evaporation, function-based interpolation of the water bodies’ areas and volumes allowed calculation of daily infiltration into the depression beds. The infiltration was maximal (5–40 mm/day) at onset of spring and decreased with time during the study period. Use of the spatially variable infiltration rates improved steady-state shallow groundwater simulations.


2017 ◽  
Vol 9 (1) ◽  
pp. 145-162
Author(s):  
Jan Kopp ◽  
Jindřich Frajer ◽  
Marie Novotná

Abstract This study is focused on the changing of areas of water bodies in selected villages of the Pilsen Region (Czechia). We researched several different types of rural settlements and three time horizons with the help of old maps, orthophoto maps and GIS tools. To capture the influence of their location within the urban system, we chose 15 places from four categories (inner suburban area, outside suburban area, rural area, periphery rural area) depending on their distance to the core of the Pilsen agglomeration. There is no significant change in the amount of water bodies between the first reference period (1838-1839) and the second period (1957-1963) in the selected settlements. However, the third period (2013-2015) is characterized by the emergence of a large number of small water bodies - swimming pools and garden ponds. Based on the results of our research we identified the declining importance of public water bodies in some of the settlements. However, we have identified a notable prevalence of garden ponds which have a more positive ecological impact than pools. The proportion of private water bodies (covered and uncovered pools and garden ponds) in the total area of water bodies in the rural settlements in most cases is less than 20%, in the suburban settlements up to 100%. Peripheral settlements have a below-average share of these water bodies. The difference between the number of pools in different settlements is related to the proportion of newly built houses there. Although there are relatively fewer pools in rural settlements, the difference compared to the situation in suburban settlements is not pronounced due to the change in lifestyle in rural areas and the change in functions of some villages to recreational areas. Influence of pools on water consumption is dependent on the individual exchange technology of water in swimming pools. Filling of the pool before the season can overload the capacity of the local water supply.


2021 ◽  
Author(s):  
Eduard Mas‐Carrió ◽  
Judith Schneider ◽  
Battogtokh Nasanbat ◽  
Samiya Ravchig ◽  
Mmabaledi Buxton ◽  
...  

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