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Metacommunity ecology represents a framework for identifying linkages between environmental heterogeneity, spatial processes, and local communities of organisms. Despite advancements in metacommunity theory, there remains a need to understand temporal dynamics of multi‐taxa metacommunities in variable ecosystems such as intermittent streams. We present a review of literature, three recent conceptual models, and a case study regarding metacommunity temporal dynamics in intermittent streams. The literature review revealed that the cumulative number of studies addressing temporal dynamics in aquatic metacommunities steadily increased between 2012 and 2020. Intermittent streams were the fourth‐most commonly studied ecosystem and interdisciplinary studies involving multiple taxa were the third‐most common taxonomic focus. The most common analytical method was variation partitioning, and analysis of beta diversity components surpassed both distance decay and elements of metacommunity structure as the second‐most used method from 2018 to 2020. Three recent conceptual models describing metacommunity dynamics in intermittent streams predict: (a) higher local species richness (i.e., alpha diversity) during rewetting and wet hydrologic phases, (b) stronger effects of dispersal over environmental sorting during the rewetting and wet phases, and (c) emergence of primarily nested structures during the wet hydrologic phase. When tested in a case study focused on microbes, aquatic invertebrates, and fishes, each of these predictions were partially, but not completely supported. Our results reveal expanding interest in temporal aspects of aquatic metacommunity structure and highlight how research in intermittent streams is poised to simultaneously advance basic metacommunity ecology and applied conservation biology through continued refinement of new and existing conceptual syntheses. This article is categorized under:Water and Life > Nature of Freshwater EcosystemsWater and Life > Stresses and Pressures on EcosystemsWater and Life > Conservation, Management, and Awareness [ABSTRACT FROM AUTHOR]

Abstract: Extirpated organisms are reintroduced into their former ranges worldwide to combat species declines and biodiversity losses. The growing field of reintroduction biology provides guiding principles for reestablishing populations, though criticisms remain regarding limited integration of initial planning, modeling frameworks, interdisciplinary collaborations, and multispecies approaches. We used an interdisciplinary, multispecies, quantitative framework to plan reintroductions of three fish species into Abrams Creek, Great Smoky Mountains National Park, USA. We first assessed the appropriateness of habitat at reintroduction sites for banded sculpin (Cottus carolinae), greenside darter (Etheostoma blennioides), and mottled sculpin (Cottus bairdii) using species distribution modeling. Next, we evaluated the relative suitability of nine potential source stock sites using population genomics, abundance estimates, and multiple‐criteria decision analysis (MCDA) based on known correlates of reintroduction success. Species distribution modeling identified mottled sculpin as a poor candidate, but banded sculpin and greenside darter as suitable candidates for reintroduction based on species‐habitat relationships and habitats available in Abrams Creek. Genotyping by sequencing revealed acceptable levels of genetic diversity at all candidate source stock sites, identified population clusters, and allowed for estimating the number of fish that should be included in translocations. Finally, MCDA highlighted priorities among candidate source stock sites that were most likely to yield successful reintroductions based on differential weightings of habitat assessment, population genomics, and the number of fish available for translocation. Our integrative approach represents a unification of multiple recent advancements in the field of reintroduction biology and highlights the benefit of shifting away from simply choosing nearby populations for translocation to an information‐based science with strong a priori planning coupled with several suggested posteriori monitoring objectives. Our framework can be applied to optimize reintroduction successes for a multitude of organisms and advances in the science of reintroduction biology by simultaneously addressing a variety of past criticisms of the field. [ABSTRACT FROM AUTHOR]

Environmental DNA (eDNA) can be used as an assessment tool to detect populations of threatened species and provide fine-scale data required to make management decisions. The objectives of this project were to use quantitative PCR (qPCR) to: (i) detect spiked salamander DNA in soil, (ii) quantify eDNA degradation over time, (iii) determine detectability of salamander eDNA in a terrestrial environment using soil, faeces, and skin swabs, (iv) detect salamander eDNA in a mesocosm experiment. Salamander eDNA was positively detected in 100% of skin swabs and 66% of faecal samples and concentrations did not differ between the two sources. However, eDNA was not detected in soil samples collected from directly underneath wild-caught living salamanders. Salamander genomic DNA (gDNA) was detected in all qPCR reactions when spiked into soil at 10.0, 5.0, and 1.0 ng/g soil and spike concentration had a significant effect on detected concentrations. Only 33% of samples showed recoverable eDNA when spiked with 0.25 ng/g soil, which was the low end of eDNA detection. To determine the rate of eDNA degradation, gDNA (1 ng/g soil) was spiked into soil and quantified over seven days. Salamander eDNA concentrations decreased across days, but eDNA was still amplifiable at day 7. Salamander eDNA was detected in two of 182 mesocosm soil samples over 12 weeks ( n = 52 control samples; n = 65 presence samples; n = 65 eviction samples). The discrepancy in detection success between experiments indicates the potential challenges for this method to be used as a monitoring technique for small-bodied wild terrestrial salamander populations. [ABSTRACT FROM AUTHOR]

The flow of energy within an ecosystem can be considered either top-down, where predators influence consumers, or bottom-up, where producers influence consumers. Plethodon cinereus (Red-backed Salamander) is a terrestrial keystone predator who feeds on invertebrates within the ecosystem. We investigated the impact of the removal of P. cinereus on the detritivore food web in an upland deciduous forest in northwest Ohio, U.S.A. A total of eight aluminum enclosures, each containing a single P. cinereus under a small log, were constructed in the deciduous forest. On Day 1 of the experiment, four salamanders were evicted from four of the eight enclosures. Organic matter and soil were collected from the center of each enclosure at Day 1 and Day 21. From each sample, DNA was extracted, fungal-specific amplification performed, and 454 pyrosequencing was used to sequence the nuclear ribosomal internal transcribed spacer (ITS2) region and partial ribosomal large subunit (LSU). Changes in overall fungal community composition or species diversity were not statistically significant between treatments. Statistically significant shifts in the most abundant taxonomic groups of fungi were documented in presence but not absence enclosures. We concluded that P. cinereus does not affect the overall composition or diversity of fungal communities, but does have an impact on specific groups of fungi. This study used a metagenomics-based approach to investigate a missing link among a keystone predator, P. cinereus, invertebrates, and fungal communities, all of which are critical in the detritivore food web. [ABSTRACT FROM AUTHOR]