Changes in Biomass and Diversity of Soil Macrofauna along a Climatic Gradient in European Boreal Forests

Latitudinal gradients allow insights into the factors that shape ecosystem structure and delimit ecosystem processes, particularly climate. We asked whether the biomass and diversity of soil macrofauna in boreal forests change systematically along a latitudinal gradient spanning from 60° N to 69° N. Invertebrates (3697 individuals) were extracted from 400 soil samples (20 × 20 cm, 30 cm depth) collected at ten sites in 2015–2016 and then weighed and identified. We discovered 265 species living in soil and on the soil surface; their average density was 0.486 g d·w·m−2. The species-level diversity decreased from low to high latitudes. The biomass of soil macrofauna showed no latitudinal changes in early summer but decreased towards the north in late summer. This variation among study sites was associated with the decrease in mean annual temperature by ca 5 °C and with variation in fine root biomass. The biomass of herbivores and fungivores decreased towards the north, whereas the biomass of detritivores and predators showed no significant latitudinal changes. This variation in latitudinal biomass patterns among the soil macrofauna feeding guilds suggests that these guilds may respond differently to climate change, with poorly understood consequences for ecosystem structure and functions.

Coupling Human and Natural Systems for Sustainability: Experiences from China’s Loess Plateau

Addressing the sustainability challenges facing humanity in the Anthropocene requires the coupling of human and natural systems, rather than their separate treatment. To understand the dynamics of a coupled human and natural system (CHANS) and promote its sustainability, we proposed a conceptual cascade framework of “Pattern-Process-Service-Sustainability”. The use of this framework was systematically illustrated by a review of CHANS research experiences in China’s Loess Plateau (LP) in terms of coupling landscape patterns and ecological processes, linking ecological processes to services, and promoting social-ecological sustainability. The LP is well-known for its historically notorious soil erosion and successful vegetation restoration achieved in recent decades. Vegetation coverage in the LP has increased since 2000 due to ecological restoration. Soil erosion has been well controlled and the sediment deriving from the LP, and flowing into the Yellow River, has greatly decreased; however, overplanting, the introduction of exotic plant species, and the mismanagement of planted vegetation have also led to soil drying in some areas. Ecosystem services, especially for soil conservation and carbon sequestration, have significantly improved, although a trade-off between carbon sequestration and water supply has been identified at multiple scales. Based on the comprehensive understanding of CHANS dynamics, targeted policy and management suggestions are here proposed to support the social-ecological sustainability of the LP. The research experience accumulated on the LP offers examples of the application of the “Pattern-Process-Service-Sustainability” framework. Future research using this framework should especially examine the integrated research of multiple processes, the cascades of ecosystem structure, function, services, and human-wellbeing, the feedback mechanisms of human and natural systems, and the data and models for sustainability.

Spatial–Temporal Changes and Driving Force Analysis of Ecosystems in the Loess Plateau Ecological Screen

The ecological degradation caused by unreasonable development and prolonged utilization threatens economic development. In response to the development crisis triggered by ecological degradation, the Chinese government launched the National Barrier Zone (NBZ) Construction Program in 2006. However, few in-depth studies on the Loess Plateau Ecological Screen (LPES) have been conducted since the implementation of that program. To address this omission, based on the remote sensing image as the primary data, combined with meteorological, soil, hydrological, social, and economic data, and using GIS spatial analysis technology, this paper analyzes the change characteristics of the ecosystem pattern, quality, and dominant services of the ecosystem in the LPES from 2005 to 2015. The results show that from 2005 to 2015, the ecosystem structure in the study area was relatively stable, and the area of each ecosystem fluctuated slightly. However, the evaluation results based on FVC, LAI, and NPP showed that the quality of the ecosystem improved. The vegetation coverage (FVC) increased significantly at a rate of 0.91% per year, and the net primary productivity (NPP) had increased significantly at a rate of 6.94 gC/(m2∙a) per year. The leaf area index (LAI) in more than 66% of the regions improved, but there were still about 8% of the local regions that were degraded. During these 10 years, the soil erosion situation in LPES improved overall, and the amount of soil conservation (ASC) of the ecosystem in the LPES increased by about 0.18 billion tons. Grassland and forest played important roles in soil conservation in this area. Pearson correlation analysis and redundancy analysis showed that the soil conservation services (SCS) in the LPES were mainly affected by climate change, economic development, and urban construction. The precipitation (P), total solar radiation (SOL), and temperature (T) can explain 52%, 30.1%, and 17% of the change trends of SCS, respectively. Construction land and primary industry were negatively correlated with SCS, accounting for 22% and 8% of the change trends, respectively. Overall, from 2005 to 2015, the ecological environment of LPES showed a gradual improvement trend, but the phenomenon of destroying grass and forests and reclaiming wasteland still existed.

Critical Transitions in Lake Ecosystem State May Be Driven by Coupled Feedback Mechanisms: A Case Study from Lake Erhai, China

Critical transitions between ecosystem states can be triggered by relatively small external forces or internal perturbations and may show time-lagged or hysteretic recovery. Understanding the precise mechanisms of a transition is important for ecosystem management, but it is hampered by a lack of information about the preceding interactions and associated feedback between different components in an ecosystem. This paper employs a range of data, including paleolimnological, environmental monitoring and documentary sources from lake Erhai and its catchment, to investigate the ecosystem structure and dynamics across multiple trophic levels through the process of eutrophication. A long-term perspective shows the growth and decline of two distinct, but coupled, positive feedback loops: a macrophyte-loop and a phosphorus-recycling-loop. The macrophyte-loop became weaker, and the phosphorus-recycling-loop became stronger during the process of lake eutrophication, indicating that the critical transition was propelled by the interaction of two positive feedback loops with different strengths. For lake restoration, future weakening of the phosphorus-recycling loop or a reduction in external pressures is expected to trigger macrophyte growth and eventually produce clear water conditions, but the speed of recovery will probably depend on the rates of feedback loops and the strength of their coupling.

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.

The Impact of Pre-Slaughter Fasting on the Ruminal Microbial Population of Commercial Angus Steers

Diet impacts the composition of the ruminal microbiota; however, prior to slaughter, cattle are fasted, which may change the ruminal microbial ecosystem structure and lead to dysbiosis. The objective of this study was to determine changes occurring in the rumen after pre-slaughter fasting, which can allow harmful pathogens an opportunity to establish in the rumen. Ruminal samples were collected before and after pre-slaughter fasting from seventeen commercial Angus steers. DNA extraction and 16S rRNA gene sequencing were performed to determine the ruminal microbiota, as well as volatile fatty acid (VFA) concentrations. Microbial richness (Chao 1 index), evenness, and Shannon diversity index all increased after fasting (p ≤ 0.040). During fasting, the two predominant families Prevotellaceae and Ruminococcaceae decreased (p ≤ 0.029), whereas the remaining minor families increased (p < 0.001). Fasting increased Blautia and Methanosphaera (p ≤ 0.003), while Campylobacter and Treponema tended to increase (p ≤ 0.086). Butyrate concentration tended to decrease (p = 0.068) after fasting. The present findings support that fasting causes ruminal nutrient depletion resulting in dysbiosis, allowing opportunistic pathogens to exploit the void in the ruminal ecological niche.

Climate Warming Increased Spring Leaf-Out Variation Across Temperate Trees in China

Leaf-out phenology plays a key role in ecosystem structure and functioning. Phenological changes have often been linked to climatic factors and have received considerable attention, with most studies focusing on trends of leaf-out phenology. Leaf-out variation (LOV), which reflects the stability of phenological responses, may also be affected by climate change, yet this has received less scientific attention. In this study, we examined spring LOV in response to climate change in China during the period 1963–2008 using in situ records of 15 species at 25 phenological observation sites across several climate zones and explored spatiotemporal changes of LOV and the underlying mechanisms. We observed a significant decrease of LOV toward higher latitudes (−0.2 ± 0.1 days⋅°N–1;P &lt; 0.001) across all species. Temporally, we found that the LOV was significantly increased from the period 1963–1986 (6.9 ± 2.8 days) to the period 1987–2008 (7.9 ± 3.7 days, P &lt; 0.05). Furthermore, the LOV changes between 1987–2008 and 1963–1986 were significantly smaller at high latitudes (average decrease of 1.0 day) than at low latitudes (average increase of 1.5 days). The spatial pattern of LOV is likely due to both increased heat requirements and greater temperature sensitivity at low latitudes compared with high latitudes. The temporal pattern of LOV is likely related to increased heat requirements for leaf-out during 1987–2008 when the average air temperature was higher. Our analysis indicated that the phenology response to climate change is reflected not only in the temporal trends for long time series but also in the variation of phenological dates. Results from this study improve our understanding of phenological responses to climate change and could be applied in the assessment of regional phenology changes to evaluate better the impacts of climate change on ecosystem structure and function.

Invasive Water Hyacinth Limits Globally Threatened Waterbird Abundance and Diversity at Lake Cluster of Pokhara Valley, Nepal

Invasive species alter ecosystem structure and functioning, including impacts on native species, habitat alteration, and nutrient cycling. Among the 27 invasive plant species in Nepal, water hyacinth (Eichhornia crassipes) distribution is rapidly increasing in Lake Cluster of Pokhara Valley (LCPV) in the last several decades. We studied the effects of water hyacinth on threatened waterbird abundance, diversity, and physico-chemical parameters of water in the LCPV. We found areas with water hyacinth present (HP) had reduced threatened water bird abundance relative to areas where water hyacinth was absent (HA; p = 0.023). The occurrence of birds according to feeding guilds also varied between water hyacinth presence and absence habitats. Piscivorous birds were more abundant in HA areas than HP areas whereas insectivorous and omnivorous birds had greater abundance in HP areas than in HA areas. Threatened waterbird abundance and richness were greater in areas with greater water depth and overall bird abundance but declined in HP areas. Degraded water quality was also identified in HP areas. Our findings can be used as a baseline by lake managers and policy makers to develop strategies to remove or manage water hyacinth in LCPV to improve waterbird conservation.

Geo-spatial Assessment of Flood Vulnerability Areas of the Gaza Strip Towards Preparedness and Humanitarian Response Planning

Nowadays, flood and drought will become more common as climate change causes. Due to climate change consequences, flood occurrence and its impact on Gaza people have been of great concern to the Palestinian water authority, as it has a negative influence on various humanitarian and social issues. The hazards and damages resulted by flooding cause loss of life, property, displacement of people and disruption of socioeconomic activities. This research focuses on assessing Gaza Strip vulnerability to flooding using analysis of GIS-based spatial information. Not only did it consider the physical-environmental flood vulnerability, it also investigated social flood vulnerability aspects e.g., population densities. Soil and slope were considered to have the highest weight in the vulnerability mapping, as they represent the main factors in urban hydro-ecosystem structure. The long term average rainfall, a climate function factor, has the lowest weight, because it could be considered as a threat factor in addition to a vulnerability factor. This research demonstrates that urban area and population density as strong factors influencing flood vulnerability for humanitarian and saving life purposes. The findings of Geospatial analysis were used to map vulnerable areas likely to be affected in the event of flood hazard and suggest future interventions and related adaptation strategies in Gaza areas for flood mitigation.