Dealing with the promise of metabarcoding in mega-event biomonitoring: EXPO2015 unedited data

As human activities on our planet persist, causing widespread and irreversible environmental degradation, the need to biomonitor ecosystems has never been more pressing. These circumstances have required a renewal in monitoring techniques, encouraged by necessity to develop more rapid and accurate tools which will support timely observations of ecosystem structure and function. The World Exposition (from now 'EXPO2015') hosted in Milan from May to October 2015 was a global event that could be categorized as a mega-event, which can be defined as an acute environmental stressor, possibly generating biodiversity alteration and disturbance. During the six months of EXPO2015, exhibitors from more than 135 countries and 22 million visitors insisted on a 1.1 million square meters area. Faced with such a massive event, we explore the potential of DNA metabarcoding using three molecular markers to improve the understanding of anthropogenic impacts in the area, both considering air and water monitoring. Furthermore, we explore the effectiveness of the taxonomy assignment phase considering different taxonomic levels of analysis and the use of data mining approaches to predict sample origin. Unless the degree of taxa identification still remains open, our results showed that DNA metabarcoding is a powerful genomic-based tool to monitor biodiversity at the microscale, allowing us to capture exact fingerprints of specific event sites and to explore in a comprehensive manner the eukaryotic community alteration. With this work, we aim to disentangle and overcome the crucial issues related to the generalization of DNA metabarcoding in order to support future applications.

Spontaneous vegetation succession and recovery of ecosystem structure and function in a 40-year abandoned stone quarry in a Mexican tropical dryland

Background: The restoration of sites degraded by stone quarrying in drylands requires expensive interventions. However, these interventions cannot be used in tropical drylands because rural communities lack financial resources. Spontaneous vegetation succession may help restore degraded sites. However, spontaneous succession is evaluated by only comparing species composition between degraded and reference sites, without considering the structure and function of degraded sites. Question: Can spontaneous succession restore the structure and function of sites degraded by stone quarrying? Study sites and dates: San Rafael Coxcatlán, Puebla, 2013. Methods: We evaluated nine indicators of ecosystem structure and function in 4 degraded sites abandoned for 40 years and 1 reference site. Results: Spontaneous succession partially restored the structure and function of degraded sites. In all degraded sites, herb cover (20-49 %) and biocrust cover (21-51 %) were similar to those in reference site (19 %, 56 %). Three degraded sites also had canopy covers (57-76 %), shrub covers (51-52 %), and bare ground covers (2-3 %) similar to those in reference site (80 %, 42 %, 2 %). However, one degraded site displayed the opposite pattern (32 %, 8 %, 14 %). All degraded sites had lower tree cover (0-2 %), visual obstruction (6-25 %), and litter cover (3-30 %) than the reference site (21 %, 66 %, 77 %). Conclusions: Spontaneous succession helped restore the structure and function in some degraded sites.

Trends in Local Ecosystem Governance

The physical and biological factors that together determine ecosystem structure and function will be subject to enormous pressures under future climate regimes. These pressures will impact ecosystem processes and services, ranging from impacts on biodiversity to loss of essential ecosystem benefits. Ecosystem management to maintain desired ecosystem conditions will become increasingly important. Existing governance structures are insufficient to provide the necessary guidance for these management efforts. The legal literature is increasingly focused on local ecosystem governance as a viable option to fill this governance gap. For example, increasing recognition of the value of ecosystem services to local communities has driven increased efforts to protect those services through local ecosystem initiatives. The local ecosystem governance scholarship is diffuse, making the literature difficult to access. Based on a review of the legal literature on local ecosystem governance over the last 20 years, this article marshals the theoretical arguments for and against local governance and identifies ongoing efforts to implement local ecosystem governance. The article also identifies both emerging challenges to local ecosystem governance and potential ways to address those challenges. From this review emerges actionable recommendations and critical research needs to improve local ecosystem governance.

An experimental approach for crown to whole-canopy defoliation in forests

Canopy defoliation is an important source of disturbance in forest ecosystems that has rarely been represented in large-scale manipulation experiments. Scalable crown to canopy level experimental defoliation is needed to disentangle effects of variable intensity, timing, and frequency on forest structure, function, and mortality. We present a novel pressure washing-based defoliation method that can be: implemented at the canopy-scale, throughout the canopy volume, targeted to individual leaves/trees, and completed within a timeframe of hours/days. Pressure washing proved successful at producing consistent leaf-level and whole-canopy defoliation with 10-20% reduction in leaf area index and consistent leaf surface area removal across branches and species. This method allows for stand-scale experimentation on defoliation disturbance in forested ecosystems and has the potential for broad application. Studies utilizing this standardized method could promote mechanistic understanding of defoliation effects on ecosystem structure and function and development of synthetic understanding across forest types, ecoregions, and defoliation sources.

Experimental warming differentially affects vegetative and reproductive phenology of tundra plants

Rapid climate warming is altering Arctic and alpine tundra ecosystem structure and function, including shifts in plant phenology. While the advancement of green up and flowering are well-documented, it remains unclear whether all phenophases, particularly those later in the season, will shift in unison or respond divergently to warming. Here, we present the largest synthesis to our knowledge of experimental warming effects on tundra plant phenology from the International Tundra Experiment. We examine the effect of warming on a suite of season-wide plant phenophases. Results challenge the expectation that all phenophases will advance in unison to warming. Instead, we find that experimental warming caused: (1) larger phenological shifts in reproductive versus vegetative phenophases and (2) advanced reproductive phenophases and green up but delayed leaf senescence which translated to a lengthening of the growing season by approximately 3%. Patterns were consistent across sites, plant species and over time. The advancement of reproductive seasons and lengthening of growing seasons may have significant consequences for trophic interactions and ecosystem function across the tundra.

A biomass equation dataset for common shrub species in China

Shrub biomass equations provide an accurate, efficient and convenient method in estimating biomass of shrubland ecosystems and biomass of the shrub layer in forest ecosystems at various spatial and temporal scales. In recent decades, many shrub biomass equations have been reported mainly in journals, books and postgraduate's dissertations. However, these biomass equations are applicable for limited shrub species with respect to a large number of shrub species widely distributed in China, which severely restricted the study of terrestrial ecosystem structure and function, such as biomass, production, and carbon budge. Therefore, we firstly carried out a critical review of published literature (from 1982 to 2019) on shrub biomass equations in China, and then developed biomass equations for the dominant shrub species using a unified method based on field measurements of 738 sites in shrubland ecosystems across China. Finally, we constructed the first comprehensive biomass equation dataset for China’s common shrub species. This dataset consists of 822 biomass equations specific to 167 shrub species and has significant representativeness to the geographical, climatic and shrubland vegetation features across China. The dataset is freely available at https://doi.org/10.11922/sciencedb.00641 for noncommercial scientific applications, and this dataset fills a significant gap in woody biomass equations and provides key parameters for biomass estimation in studies on terrestrial ecosystem structure and function.

Housekeeping in the Hydrosphere: Microbial Cooking, Cleaning, and Control under Stress

Who’s cooking, who’s cleaning, and who’s got the remote control within the waters blanketing Earth? Anatomically tiny, numerically dominant microbes are the crucial “homemakers” of the watery household. Phytoplankton’s culinary abilities enable them to create food by absorbing sunlight to fix carbon and release oxygen, making microbial autotrophs top-chefs in the aquatic kitchen. However, they are not the only bioengineers that balance this complex household. Ubiquitous heterotrophic microbes including prokaryotic bacteria and archaea (both “bacteria” henceforth), eukaryotic protists, and viruses, recycle organic matter and make inorganic nutrients available to primary producers. Grazing protists compete with viruses for bacterial biomass, whereas mixotrophic protists produce new organic matter as well as consume microbial biomass. When viruses press remote-control buttons, by modifying host genomes or lysing them, the outcome can reverberate throughout the microbial community and beyond. Despite recognition of the vital role of microbes in biosphere housekeeping, impacts of anthropogenic stressors and climate change on their biodiversity, evolution, and ecological function remain poorly understood. How trillions of the smallest organisms in Earth’s largest ecosystem respond will be hugely consequential. By making the study of ecology personal, the “housekeeping” perspective can provide better insights into changing ecosystem structure and function at all scales.