Changes In Key Drivers Research Articles

Combining predictive models with future change scenarios can produce credible forecasts of COVID-19 futures.

The advent and distribution of vaccines against SARS-CoV-2 in late 2020 was thought to represent an effective means to control the ongoing COVID-19 pandemic. This optimistic expectation was dashed by the omicron waves that emerged over the winter of 2021/2020 even in countries that had managed to vaccinate a large fraction of their populations, raising questions about whether it is possible to use scientific knowledge along with predictive models to anticipate changes and design management measures for the pandemic. Here, we used an extended SEIR model for SARS-CoV-2 transmission sequentially calibrated to data on cases and interventions implemented in Florida until Sept. 24th 2021, and coupled to scenarios of plausible changes in key drivers of viral transmission, to evaluate the capacity of such a tool for exploring the future of the pandemic in the state. We show that while the introduction of vaccinations could have led to the permanent, albeit drawn-out, ending of the pandemic if immunity acts over the long-term, additional futures marked by complicated repeat waves of infection become possible if this immunity wanes over time. We demonstrate that the most recent omicron wave could have been predicted by this hybrid system, but only if timely information on the timing of variant emergence and its epidemiological features were made available. Simulations for the introduction of a new variant exhibiting higher transmissibility than omicron indicated that while this will result in repeat waves, forecasted peaks are unlikely to reach that observed for the omicron wave owing to levels of immunity established over time in the population. These results highlight that while limitations of models calibrated to past data for precisely forecasting the futures of epidemics must be recognized, insightful predictions of pandemic futures are still possible if uncertainties about changes in key drivers are captured appropriately through plausible scenarios.

Key drivers of soil arthropod community shift across a subalpine forest series vary greatly with litter and topsoil layers

Soil arthropods play crucial roles in carbon and nutrient cycling in forest ecosystems. The structure and biodiversity of soil arthropod communities may vary considerably with forest succession and across soil layers due to changes in key drivers, which needs to be fully investigated. Arthropod communities in both litter and topsoil (0–5 cm) layers were simultaneously investigated in the subalpine deciduous broadleaved shrub (S1) and forest (S2), coniferous and broadleaved mixed forest (S3), and half-mature (S4), mature (S5), and overmature (S6) coniferous forests in Wanglang National Nature Reserve. The dominant taxa and common taxa in litter and topsoil layers shifted with forest succession. The litter layer had the most fungivores and saprophages, while the topsoil layer had the most saprophages. From S1 to S4, individual densities and functional groups of soil arthropod declined, then increased continuously. The Shannon-Wiener index, Pielou index, and Margalef index of arthropod communities in litter and topsoil layers declined from S1 (S2) to S4, then increased; for each functional group in the topsoil layer, these indices varied more significantly with forest succession than those in the litter layer. The structure and diversity of the soil arthropod community in the litter layer were significantly influenced by coarse woody debris stock, and those in the topsoil layer were significantly influenced by canopy density and the C/N ratio, based on RDA analysis. In conclusion, the key drivers of arthropod community shift with forest succession differed between litter and topsoil layers, which allowed arthropod communities to show different sensitivity to the environment change. This study contributes to an in-depth understanding of the ecological impact of forest succession changes on soil arthropods.

The prevalence of renewable energy in the Russian energy market

The energy crisis of 1973-1974 showed that it is difficult to constantly increase the power supply of production, based only on traditional energy sources. The power supply of society is the basis of its scientific and technological progress. It means that it is necessary to introduce unconventional, alternative energy sources more widely. Unlike fossil fuels, unconventional forms of energy are not limited to geologically reserves. Their use and consumption does not lead to the inevitable exhaustion of stocks. However, currently, the reform of world energy markets and increasing the share of renewable energy sources in their structure is a long and innovative process. Lots of countries (Russia in particular) bear significant risks because of reforming their own energy market, which causes a slight increase in the share of renewable energy sources. In this regard, the purpose of this study is to analyse the influence of environmental factors on the development of renewable energy sources in Russia. The result of this study is a system of econometric equations, which allows to evaluate the impact of changes in key drivers of the development of the renewable energy market.

Consequences of spatial heterogeneity for ecosystem services in changing forest landscapes: priorities for future research

Changes in key drivers (e.g., climate, disturbance regimes and land use) may affect the sustainability of forest landscapes and set the stage for increased tension among competing ecosystem services. We addressed two questions about a suite of supporting, regulating and provisioning ecosystem services in each of two well-studied forest landscapes in the western US: (1) How might the provision of ecosystem services change in the future given anticipated trajectories of climate, disturbance regimes, and land use? (2) What is the role of spatial heterogeneity in sustaining future ecosystem services? We determined that future changes in each region are likely to be distinct, but spatial heterogeneity (e.g., the amount and arrangement of surviving forest patches or legacy trees after disturbance) will be important in both landscapes for sustaining forest regeneration, primary production, carbon storage, natural hazard regulation, insect and pathogen regulation, timber production and wildlife habitat. The paper closes by highlighting five general priorities for future research. The science of landscape ecology has much to contribute toward understanding ecosystem services and how land management can enhance—or threaten—the sustainability of ecosystem services in changing landscapes.

Reversal of multicentury tree growth improvements and loss of synchrony at mountain tree lines point to changes in key drivers

Summary1. Altitudinal tree line ecotones (ATE) are among the most sensitive plant formations facing global warming as the altitudinal decrease in temperature is considered the driver controlling the upper elevation limit of tree lines world‐wide. In this study, we attempted to answer the following questions: (i) how have the conditions during the last 2–3 centuries affected ATE tree growth (physiology) and recruitment (demography)? and (ii) how strong is synchrony between these two processes at the ATEs?2. We used spatial sampling grids at different ATEs in two ecosystems on two subcontinents: Nothofagus pumilio in the Andes of Chilean Patagonia (46° SL) and Pinus albicaulis in the Rockies of Western Montana, USA (46° NL). Basal increment cores were extracted from trees to estimate the growth and recruitment date. An annual detrended basal area increment was estimated for each tree and was modelled against elevation and time.3. Tree growth improved over multiple centuries at all tree lines. Recently (c. 50 years), however, improvements are disappearing or reversing. The uppermost tree line trees showed moderate declines in Montana and incipient declines in Patagonia. The declines are most dramatic slightly below current tree line (c. 200 m). Tree recruitment patterns showed that tree lines have been moving uphill in both regions until at least 40–70 years ago. These movements occurred primarily through abrupt pulses upward with infilling occurring concurrently (Patagonia) or at some time thereafter (Montana).4. Synchrony between growth and recruitment occurred in the 18th and 19th centuries in both regions. This synchrony was negative in Patagonia and positive in Montana, with varying lag periods. During the 20th century, these patterns of synchrony were lost at all sites. This loss of synchrony suggests that we could be entering a global period in which temperature is no longer the dominant driver of key features of tree lines.5. Synthesis. Our study shows that at two structurally different tree lines, recent and initial declines in growth and losses of long‐term synchrony are occurring in the latter part of the 20th century. These findings are opposite to simplistic expectations of global warming effects on tree line dynamics and call for a model reformulation that uncouples drivers of growth and recruitment.

Habitat dynamics at the catchment – coast interface: contributions from ELOISE

This paper summarises contributions made by the ELOISE cluster of research projects to our understanding of European coastal habitat dynamics. ‘Habitat’ is used as the key concept defining Europe's coastal ecosystems following the European Community, which uses ‘habitat’ as formal currency in its directives on water and nature use, management and conservation. Eight aggregate habitat categories are identified: cliffs, shingle beaches, and associated kelp beds; dune complexes with freshwater wetlands; salt marsh; sandbanks and mudflats; seagrass beds, lagoons; subtidal sediments, and open sea pelagic. We distinguish between dynamics ‘within’ and ‘between’ habitats. The former tend to be coupled to physical forcing. The latter concern transitions from one habitat to another. Both types have been charted for the eight habitat categories. The Drivers – Pressures – State – Impact – Response framework is used to review the possible impact on habitat of foreseen future changes in key drivers and pressures, which would lead to major changes in the state of European coastal ecosystems. Drivers comprise climate change, the increase in built-up area, expansion and intensification of trade, ports and related industry, as well as of fishing, aquaculture and agriculture. Together these would lead to sea level rise and coastal erosion, contamination, eutrophication, and loss of biodiversity, but to different extents in Europe's regional seas. This report concludes with specific recommendations for future European coastal research.

Evaporative cooling: An assessment of california market potential and estimated impacts of key deployment barriers

The California Energy Commission has recognized evaporative cooling space conditioning as a key demand-side “Opportunity Technology,” which offers compelling energy, economic development and environmental benefits to the state. In 1993, the Commission lead an effort to form an industry Collaborative of Stakeholders whose primary focus was to improve market penetration through the identification and elimination of the key barriers to technology deployment. More recently, the Commission has supported this objective through the funding of a statewide market assessment of evaporative cooling in the residential and commercial market segments with Regional Economic Research, Inc. of San Diego, California under Contract No. 500-93-027. Summary data and results from this work are presented in this paper. Baseline forecasts of market shares and the associated energy impacts within the residential and commercial market segments, including new construction and existing facilities, were then developed for each statewide planning area and utility climate zone in California. Thereafter, forecasts of the sensitivity of market shares and energy impacts to changes in key drivers (e. g., awareness, technology costs, and select non-economic drivers) were generated to establish the relative importance of each of the technology market drivers. Finally, Achievable Potential was estimated in the form of market shares and associated energy savings, based upon assumptions with respect to the achievable reductions in evaporative cooling deployment barriers.