Evidence of non‐stationary relationships between climate and forest responses: Increased sensitivity to climate change in Iberian forests

Climate and forest structure are considered major drivers of forest demography and productivity. However, recent evidence suggests that the relationships between climate and tree growth are generally non‐stationary (i.e. non‐time stable), and it remains uncertain whether the relationships between climate, forest structure, demography and productivity are stationary or are being altered by recent climatic and structural changes. Here we analysed three surveys from the Spanish Forest Inventory covering c. 30 years of information and we applied mixed and structural equation models to assess temporal trends in forest structure (stand density, basal area, tree size and tree size inequality), forest demography (ingrowth, growth and mortality) and above‐ground forest productivity. We also quantified whether the interactive effects of climate and forest structure on forest demography and above‐ground forest productivity were stationary over two consecutive time periods. Since the 1980s, density, basal area and tree size increased in Iberian forests, and tree size inequality decreased. In addition, we observed reductions in ingrowth and growth, and increases in mortality. Initial forest structure and water availability mainly modulated the temporal trends in forest structure and demography. The magnitude and direction of the interactive effects of climate and forest structure on forest demography changed over the two time periods analysed indicating non‐stationary relationships between climate, forest structure and demography. Above‐ground forest productivity increased due to a positive balance between ingrowth, growth and mortality. Despite increasing productivity over time, we observed an aggravation of the negative effects of climate change and increased competition on forest demography, reducing ingrowth and growth, and increasing mortality. Interestingly, our results suggest that the negative effects of climate change on forest demography could be ameliorated through forest management, which has profound implications for forest adaptation to climate change.     

Characterization and antioxidant activity of an exopolysaccharide produced by Leuconostoc pseudomesenteroides JF17 from juçara fruits (Euterpe edulis Martius)

Juçara palm tree is considered an important species in the Atlantic forest ecosystem and the exploitation of its fruits is a main sustainable strategy adopted to its maintenance. Among several microorganisms in the juçara fruits, were found lactic acid bacteria (LAB) highly capable of synthesizing exopolysaccharides (EPS). Thus, the EPS synthesized by Leuconostoc pseudomesenteroides JF17 was characterized according to its chemical structure, physicochemical properties and antioxidant activity. HPLC analysis showed that the EPS consisted of a homopolysaccharide composed of glucose units, FT-IR spectroscopy revealed a dextran, confirmed by ¹H and ¹³C NMR spectra which showed the composition of the polysaccharide, d-glucose units bound by α-(1→6). The EPS showed high water retention capacity, 507.812 ± 47.471 %, and may be related to the porous structure revealed by SEM images. Thermal analysis indicated that the EPS had excellent thermal stability with degradation temperature of 320.8 °C and melting point at 279.81 °C, with the enthalpy of 106.557 J/g. The EPS also presented sequestration ability on different free radicals tested, indicating high antioxidant activity. The results suggest that L. pseudomesenteroides JF17 might be widely used in the production of dextran which has potential qualities for applications in the food industry.     

Toward enhanced performance of integrated photo-bioelectrochemical systems: Taxa and functions in bacteria–algae communities

An integrated photo-bioelectrochemical (IPB) system uses microalgae in the cathode of a microbial fuel cell to achieve higher electricity generation and nutrient removal from wastewater. Using multivariate analysis and surveys of IPB studies, this paper identifies key algal and bacterial taxa and discusses their functions critical for IPB performance. Unicellular algae with high photosynthetic oxygen production and biofilm formation can enhance IPB energy production. Diverse bacterial taxa achieve nitrogen transformations and can improve total nitrogen removal. Understanding bacteria–algae interactions via quorum sensing in the IPB cathode may potentially aid in boosting system performance. Future advances in development of IPBs for wastewater treatment will benefit from interdisciplinary collaboration in analysis of microbial community functions.     

Phenology responses of temperate butterflies to latitude depend on ecological traits

Global change influences species’ seasonal occurrence, or phenology. In cold‐adapted insects, the activity is expected to start earlier with a warming climate, but contradictory evidence exists, and the reactions may be linked to species‐specific traits. Using data from the GBIF database, we selected 105 single‐brooded Holarctic butterflies inhabiting broad latitudinal ranges. We regressed patterns of an adult flight against latitudes of the records, controlling for altitude and year effects. Species with delayed flight periods towards the high latitudes, or stable flight periods across latitudes, prevailed over those that advanced their flight towards the high latitudes. The responses corresponded with the species’ seasonality (flight of early season species was delayed and flight of summer species was advanced at high latitudes) and oceanic vs. continental climatic niches (delays in oceanic, stability in continental species). Future restructuring of butterfly seasonal patterns in high latitudes will reflect climatic niches, and hence the evolutionary history of participating species.     

Spatial resolution and location impact group structure in a marine food web

Ecological processes in food webs depend on species interactions. By identifying broad‐scaled interaction patterns, important information on species' ecological roles may be revealed. Here, we use the group model to examine how spatial resolution and proximity influence group structure. We examine a data set from the Barents Sea, with food webs described for both the whole region and 25 subregions. We test how the group structure in the networks differ comparing (1) the regional metaweb to subregions and (2) subregion to subregion. We find that more than half the species in the metaweb change groups when compared to subregions. Between subregions, networks with similar group structure are spatially related. Interestingly, although species overlap is important for similarity in group structure, there are notable exceptions. Our results highlight that species ecological roles vary depending on fine‐scaled differences in the patterns of interactions, and that local network characteristics are important to consider.     

Operation Crayweed: Ecological and sociocultural aspects of restoring Sydney’s underwater forests

Operation Crayweed focuses on the restoration of underwater forests that disappeared from the coastline of Sydney, Australia’s largest city, 40 years previously. We show how a combination of science, hands‐on restoration, community engagement and art has helped the project to reach its goals as well as raise awareness about the importance of underwater kelp forests that are experiencing global decline.