Long-term Changes Research Articles

Pediatric perspective: the microbiome in vertical HIV-infection: unravelling gaps, challenges, and therapeutic potential.

The intricate interplay between HIV and the host microbiota has emerged as a significant area of investigation with therapeutic potential. Despite numerous studies on this complex interaction in adults, vertically acquired infections, which have distinct immunological and virological characteristics, remain relatively understudied. Disturbances, including prolonged exposure to HIV and antiretroviral therapy, significantly impact the gut microbiome, though isolating these effects from other influencing factors is challenging. Children and adolescents living with HIV exhibit reduced microbiome diversity and potential imbalances between beneficial and pathogenic taxa. However, most available data focus on microbiome composition rather than function. The observed variations in specific microbial phyla are intriguing, but their health effects are unknown. Although modulating the microbiota may be theoretically easier during childhood, few interventional trials have included children. Therapeutic interventions aimed at modulating the gut microbiome in children with HIV have shown limited impact, and their ability to induce long-term microbiome changes remains uncertain. A more functional, longitudinal approach, along with an ecological perspective, is needed to understand the complex interplay between the microbiome and the host. This will help clarify the relevance of microbiota alterations and their potential implications for clinical outcomes, such as inflammation and immune reconstitution in pediatric HIV.

Long-term evaluation of surface topographic and topsoil grain composition changes in an agricultural landscape

Understanding long-term changes in topography and topsoil grain composition is crucial for the management of agricultural landscapes, especially in areas prone to wind erosion. This study investigates long-term changes in topography and topsoil grain composition within an agricultural landscape in south-western Slovakia. To analyse topographic changes over time, we used high-precision positioning measurements and airborne laser scanning to create digital terrain models (DTM) for the years 2011, 2017 and 2020. To assess changes in soil grain composition, we performed grain size analyses on soil samples collected during three different periods: M1 (1961–1970), M2 (2009–2015) and M3 (2015–2016). Changes in soil texture were evaluated to understand the impact of wind erosion on soil composition. The influence of windbreaks was also analysed by comparing the accumulation and deflation processes. The results showed significant changes in both topography and soil texture over the study period. The DTMs showed marked differences in the accumulation and deflation processes, highlighting areas affected by wind erosion. Comparisons of soil samples showed a shift in dominant soil types from loam and clay loam to silty loam, highlighting the effects of wind erosion. Analysis revealed a decrease in clay and silt content and an increase in sand content, indicating wind-induced soil degradation. The presence of windbreaks played a crucial role in reducing soil erosion by reducing wind speed, promoting soil accumulation and stabilising the landscape up to 80 m windward and 20 m leeward. The study highlights the complex interplay of climate and wind factors in shaping topography and soil properties and emphasises the protective role of windbreaks in agricultural landscapes over time. Our results show that wind erosion significantly alters soil texture, which can affect agricultural productivity. However, windbreaks have proven to be an effective measure in reducing soil erosion and maintaining soil quality.

Designing a Measurement Feedback System for Personality Disorders: Should Outcome Monitoring be Based on Symptom Severity or Personality Functioning?

Measurement feedback systems (MFS) providing insight in treatment progress can improve mental healthcare outcomes. However, there is no uniform measurement feedback system that could be used to measure treatment progress for personality disorders (PD). This study compared two types of measures: a generic measure for symptom severity (Brief Symptom Index, BSI) and a specific measure for personality functioning (Severity Indices of Personality Problems, SIPP) at different points in time in order to provide insight in the most suitable measuring moment for a MFS for PD. This study is conducted in a sample of 996 Dutch PD patients (mean age 33.51 (SD 10.42), 73.1% female). Symptom severity and personality functioning were assessed before and multiple times during treatment, using a timespan of 24months. Outcomes were examined over time using multilevel modeling. Symptom severity (generic measure) and personality functioning (specific measure) improved equally after 24months. However, during these 24months, different patterns of change were observed for symptom severity compared to severity of personality problems. In general, symptom severity decreased most during the 1st months of treatment, whereas personality functioning improved only after 6months of treatment. A generic instrument of symptom severity is able to measure early changes in symptom distress but may not be able to measure longer term changes in personality functioning. The authors discuss policy implications for benchmarking using specific measures in the treatment of personality disorders.

Association of baseline serum sodium with long-term outcomes in newly diagnosed coronary heart disease patients without heart failure: a prospective cohort study

Sodium is crucial for maintaining cardiovascular health, especially in relation to heart failure. The impact of baseline serum sodium concentrations on the outcomes of newly diagnosed coronary heart disease (CHD) without heart failure remains unclear. This prospective cohort study included 681 patients who were newly diagnosed with CHD. Cox proportional hazards models and restricted cubic spline (RCS) analysis were used to assess the relationship between serum sodium concentrations and major adverse cardiovascular events. The improvement in traditional prediction models by the addition of serum sodium concentrations was assessed using changes in the C-statistic, net reclassification improvement (NRI), and integrated discrimination improvement (IDI). During a median follow-up of 51.04 months (IQR: 40.88–53.80 months), 131 events were recorded. Multivariate Cox proportional hazards models showed that the L2 group (136–138.9 mmol/L) had the highest MACE risk. Compared to L2, the hazard ratios (HRs) and 95% confidence intervals (CIs) for the L1 (130–135.9 mmol/L), L3 (139–140.9 mmol/L), L4 (141–142.9 mmol/L), and L5 (143–147.0 mmol/L) groups were 0.31 (0.14–0.70, P = 0.005), 0.48 (030–0.78, P = 0.003), 0.56 (0.34–0.92, P = 0.022), and 0.37 (0.22–0.64, P < 0.001), respectively. Including serum sodium concentrations in the prediction model significantly improved the C-statistic from 0.647 to 0.679 (P = 0.022), with an NRI of 0.338 (P < 0.001) and an IDI of 0.026 (P < 0.001). RCS analysis showed a nonlinear relationship: within the 130–138 mmol/L sodium range, MACE risk gradually increased with higher sodium levels (HR 1.39, 95% CI 1.09–1.76, P = 0.008); whereas within the 138–147 mmol/L range, the risk gradually decreased (HR 0.88, 95% CI 0.80–0.98, P = 0.014). Baseline serum sodium concentrations are significantly associated with long-term cardiovascular risk in newly diagnosed CHD patients, showing an inverted U-shaped relationship, whereas low serum sodium may be specifically linked to higher risks of death and nonfatal myocardial infarction. Further research is needed to explore the impact of long-term changes in serum sodium concentrations on disease prognosis.

GC Insights: Communicating long-term changes in local climate risk using a physically plausible causal chain

Abstract. Directly linking greenhouse gas emissions or global warming to experiences of local climatic changes is a potentially important communication tool. Using observations, we develop a physically plausible “causal chain” visualisation to demonstrate the connections between global carbon dioxide emissions and local climate events. We highlight how increased flood risk in one river basin in the UK could be discussed with people directly affected by recent floods.

Holocene ecosystem and temperature development inferred from invertebrate remains in Zminje Jezero (Dinaric Alps, Montenegro)

AbstractLake Zminje Jezero (1535 m a.s.l.) in Montenegro was studied for chironomid and other aquatic invertebrate remains in a sediment sequence dating back to 12,000 calibrated 14C years before present (cal yr BP), providing, to our knowledge, the first lake-sediment record studied for chironomids and other associated chitinous aquatic invertebrate remains in the Dinaric Alps. Changes in chironomid and other invertebrate remains along the record make it possible to constrain changes of relevant environmental variables for aquatic invertebrates in the lake including temperature, oxygen availability, trophic status and water depth. The results suggest moderate changes in trophic conditions with chironomid assemblages indicating meso- to eutrophic conditions during the analysed interval. Invertebrate assemblages were typical for lakes with relatively high oxygen availability with a minor trend during the middle to late Holocene to conditions observed in lakes that are more hypoxic. A change in temperature is suggested in the earlier part of the record when the share of chironomid taxa adapted to warmer conditions increased, at the Younger Dryas to Holocene transition, whereas later no particularly pronounced shifts in temperature-sensitive taxa were observed. July air temperatures were estimated based on chironomid assemblages using a transfer function based on calibration data consisting of 117 lakes sampled in the Swiss Alps and northern Switzerland. The results suggest that temperatures rapidly increased by 5 °C at the onset of the Holocene (11,500 cal yr BP) leading to a relatively warm early to mid-Holocene and thereafter slightly decreased during the late Holocene. Reconstructed temperatures are discussed together with a previously published pollen record for our study site and are broadly consistent with other chironomid-based temperature reconstructions from Central, Eastern and Southern Europe. From ca. 3000 cal yr BP sedimentation rates increased and from ca. 500 cal yr BP onwards pollen data suggest that the vegetation and lake catchment were affected by human activities, possibly influencing chironomid and other invertebrate assemblages in the lake and thereby also reconstructed temperatures. Overall, our results show that combining analyses of chironomid and other invertebrate assemblages can provide valuable insights into long-term environmental changes and can provide temperature reconstructions for small mountain lakes in the Balkans, such as Zminje Jezero.

Modeling Organismal Responses to Changing Environments.

Throughout their lives, organisms must integrate and maintain stability across complex developmental, morphological, and physiological systems, all while responding to changing internal and external environments. Determining the mechanisms underlying organismal responses to environmental change and development is a major challenge for biology. This is particularly important in the face of the rapidly changing global climate, increasing human populations, and habitat destruction. In January 2024, we organized a symposium to highlight some current efforts to use modeling to understand organismal responses to short- and long-term changes in their internal and external environments. Our goal was to facilitate collaboration and communication between modelers and organismal biologists, which is one of the major aims of the Organismal Systems-type Modeling Research Coordination Network, OSyM. Accompanying this introduction are a series of papers that are aimed to enhance research and education in linking organismal biology and modeling and contribute to building a new community of scientists to tackle important questions using this approach.

Generational Change in Work-Related Agency Beliefs in Poland

AbstractIn this study we analyze beliefs on work-related agency in two cohorts of Poles, born in 1970–1971 and in 1988–1989. Both institutional environment and labor opportunities set these two generations much apart, as the first one grew up under communism and entered the transforming labor market plagued with high unemployment, whereas the second enjoyed the opportunities set by Poland’s European Union accession. The comparison is based on nationally representative samples and synchronizes the measurement on the same moment in the life cycle (both cohorts were surveyed at 30 years of age). In the analysis we aim to verify whether there are significant differences in beliefs about means to success in career, as well as in the respondents’ own traits and resources in this respect. These differences, in turn, can be related to deeper, long-term changes in socialization and social structure, as this was often presumed in previous research (it implied further convergence with Western societies). Work-related agency is measured using a shortened version of the Control Agency Means–Ends in Adulthood Questionnaire developed by Diewald et al. Results show that there are distinct dimensions in which both generations are similar and in which they prove to be very distinct. The study also uncovers a more profound change in work-related agency in women and confirms the well-established relationship between occupational structure and agency.

Long-term changes in the density and composition of profundal macrobenthos in Lake Biwa from 1966 to 2000

Lake Biwa, the largest lake in Japan, has been affected by eutrophication and climate warming since the 20th century. To examine the effects of these environmental changes on dominant macrobenthos species in Lake Biwa, the density and composition of these organisms were determined monthly from 1966 to 2000 at an offshore station in the lake, and analyzed in terms of various physicochemical factors. Annual mean bottom temperatures at the site generally remained stable (6.1–8.0°C) until 1985, increased from 1985 (6.5°C) to 1990 (8.3°C), and remained high thereafter (7.4–8.3°C). Branchiura sowerbyi dominated the oligochaete community in terms of density and biomass until 1985. Oligochaete density increased after 1986, dominated by B. sowerbyi, Limnodrilus spp., and Tubifex tubifex. Although the increase in macrobenthic density after 1986 was mainly explained by an increase in T. tubifex density (3811–8076 individuals m–2), total macrobenthos biomass was mainly controlled by B. sowerbyi (1.9–9.5 g m–2). Notably, the increase in T. tubifex density roughly coincided with density decreases in the benthic gobid fish Gymnogobius isaza (from 567 tons to undetectable) and the shrimp Palaemon paucidens (from 758 to 142 tons). Jesogammarus annandalei density increased from 1985, roughly coinciding with the decrease in gobid fish. These findings demonstrate the importance of biological interactions such as predation in the succession of dominant macrobenthos species in Lake Biwa.

Challenges to anticipatory coastal adaptation for transformative nature-based solutions

Much of England’s coastline is underprepared for adapting to long-term coastal change, with many coastal areas moving from ‘hold the line’ to managed realignment as this century progresses. This paper offers a unique case study of a frontage experiencing this transition. It explores the perspectives of Bacton and Walcott residents and coastal policymakers on managing the risk of coastal change for the Bacton-Walcott frontage on the Norfolk coast (UK), after the projected lifetime of a nature-based solution (NBS), known as sandscaping. Drawing upon survey and interview data, this research finds local residents have an increased sense of security of future coastal change through the perceived importance of the nearby Bacton Gas Terminal (currently supplying up to a third of the UK’s gas supply), and the protection afforded to it by sandscaping. For policymakers, sandscaping has bought time to prepare for managed realignment, whereas for residents, sandscaping has bought time to postpone it. There is a risk of maladaptation if reduced concern of future erosion affects willingness to engage in coastal adaptation in the present. This case study highlights the multiple temporal and spatial interests in coastal management, where decision-making at a local level has national-scale implications for domestic energy supply, and where novel nature-based solutions may bring additional uncertainty and complexity to building social resilience. It provides insights on the challenges of anticipatory adaptation, which is of relevance to other coastal areas looking to mitigate climate impacts and better prepare against future risk.

Long-Term Landscape Changes in the Ojców National Park (Poland) and Its Surroundings: Implications for the Effectiveness of Buffer Zones

Protected areas (PAs) serve as crucial elements in biodiversity conservation but are in danger of becoming isolated islands in human-dominated landscapes. It is related to landscape changes, especially changes in land use and land cover (LULC). Over the past decades, most research on the effectiveness of nature conservation has focused mainly on PAs, while the areas surrounding PAs are of key importance for maintaining ecological connectivity and biodiversity. Therefore, the main objective of this study was to determine the long-term changes in LULC within the selected national park in Poland and its surroundings and to assess the effectiveness of the BZ based on these changes. We hypothesized that, despite restrictions within the buffer zone, land development has intensified and increased, in the nearest surroundings of the analyzed national park. For the analysis, we selected Ojców National Park (southern Poland), one of the oldest national parks in Poland. We analyzed landscape changes before (since the 1930s) and after establishing the park and its BZ. We conducted a comprehensive quantitative analysis of the landscape structure and LULC. We used historical maps and the contemporary national LULC database. Our results showed that almost 40% of the study area consisted of lands with non-persistent LULC. The main changes include a three-fold increase in built-up areas and an increase in forest cover, mainly on abandoned agricultural land. We also found that land development around the national park is at a level similar to the general rate for the area outside the BZ. It suggests the ineffectiveness of the buffer zone in preventing land development. The identified long-term landscape changes the basis for sustainable development land management from the nature conservation perspective.

Commuting mode choice and work from home in the later stages of COVID-19: Consolidating a future focussed prediction tool to inform transport and land use planning

As COVID-19 slowly dissipated after 30 months since March 2020, working from home (WFH) continues to be popular, with support from notable numbers of employees and employers. There is growing evidence that we have either reached, or appear to be close to, a level of WFH − to some extent − that might be described as an equilibrium outcome going forward. Hence, there is a need to update any travel behaviour response models that have been developed during the passage of the pandemic. This paper sets out a commuter model for each day of the week for the Greater Sydney Metropolitan Area as of September 2022; where the alternative responses are to not work, WFH, or commute by one of ten modes available. Given the probability of WFH obtained from a mixed logit model, we construct a mapping equation to establish the sources of statistical variance by origin and destination locations that influence the incidence of WFH. The evidence is used as the basis of commenting on what this means for longer-term structural changes in network performance, the likely move to a greater focus on living locally, and the need (or otherwise) for employers to retain office space. A significant return to the office has recently been promoted by some employers, and we comment on this as to what it might mean for the future of a hybrid working location model.

Evidence of COVID-19 pandemic influence on well-being produced by urban gardening: a before-after study

The COVID-19 pandemic showed us that maintaining and increasing individual and community resilience is essential, particularly in cities. Access to urban green spaces such as parks and gardens supports resilience and well-being. Here, we studied how the pandemic influenced the attitudes towards and outcomes of urban box gardening in the city of Turku in Finland. We analyzed this small-scale social-ecological system before and during the pandemic in 2019, 2020, and 2021. We find that box gardening’s importance increased for many gardeners due to the pandemic, supporting that box gardening can enhance resilience. We find that gardeners remain motivated to cultivate but contrary to expectations, they report receiving fewer benefits, suggesting the pandemic’s negative influence on well-being extends to urban gardening. Our findings highlight the manifold and long-term influence of disturbances. The long-term changes in attitudes and outcomes suggest that the pandemic’s influence on urban gardening might be even transformative.

Decomposing the Drivers of Population Aging: A Research Note.

Population aging is an important and increasingly relevant area of study for demographers. A growing body of research seeks to determine how long-term changes in births, mortality, and migration-the three drivers of any demographic process-have shaped the present aging situation. Using variable-r decomposition and cohort data, this research note presents a formula for the change in the old-age dependency ratio to determine the extent to which relative changes in births, as well as in mortality and migration rates, contribute to aging. This perspective provides a careful and in-depth picture of aging and contributes to the debate concerning whether changes in births or mortality have had the strongest effect on population aging. When applied to Australia, the United States, and several European populations, the decomposition of the old-age dependency ratio shows that aging occurred in all populations and that changes in both births and mortality contributed to this aging. Analysis of these populations demonstrates that although they differed regarding which of these factors contributed more, changes in births prevailed as the more significant factor. In nearly all populations, migration decreased the rate of population aging.

Spatial and temporal variations of vegetation cover on the central and eastern Tibetan Plateau since the Last glacial period

Long-term changes in vegetation cover of the Tibetan Plateau (TP) are essential for understanding vegetation change under future climate. Previous studies have mainly concentrated on the Holocene and the eastern region of the TP, but here, we establish a relationship between modern pollen data (including both pollen percentage and concentration) and vegetation cover using a random forest (RF) model based on 362 soil-surface samples from the TP, as well as using it to quantitatively reconstruct the vegetation cover history of the Dagze Co (central TP, covering the last 19.5 cal. ka BP) and Koucha Lake (eastern TP, covering the last 33.8 cal. ka BP) regions. The RF results indicate that both the models based on pollen percentages or concentrations perform similarly (former: R2 = 0.538, RMSEP = 19.772%; latter: R2 = 0.540, RMSEP = 19.723%). However, when considering the reconstructed vegetation cover of Dagze Co and Koucha Lake, the results based on pollen concentrations appear to be more reliable. Before 13.4 and 16.8 cal. ka BP, Dagze Co and Koucha Lake has low vegetation cover of 25% and 30%, respectively, dominated by alpine desert or desert steppe. After that, changes in vegetation cover show different trends. At Dagze Co, the vegetation cover reaches a high level (54%) between 13.4 and 5.3 cal. ka BP, followed by a decrease until it starts increasing again at 2 cal. ka BP, in response to the change in the Indian Summer Monsoon (ISM). At Koucha Lake, the vegetation cover fluctuates at around 60%, indicating less sensitivity to climate change. Our research highlights the importance of pollen concentrations in quantitatively reconstructing past vegetation cover and the sparse vegetation status during the LGM on the TP.

Land surface response to groundwater drawdown and recovery in Taiyuan city, Northern China, analyzed with a long-term elevation change measurements from leveling and multi-sensor InSAR

In recent years, a comprehensive program of groundwater management was adopted in Taiyuan city, Northern China, with the aim to prevent the lowering of groundwater level and manage land subsidence due to excessive groundwater pumping in the past decades. Groundwater recovery has been observed in this city following the termination of groundwater pumping. While the link between land subsidence and groundwater pumping is well documented, how the land surface responds to the recovery of groundwater has not been studied in detail. In this study, we analyzed the leveling data from 1956 to 2000 to investigate changes in ground elevation in response to groundwater drawdown prior to the termination of groundwater pumping and combined them with InSAR (Interferometric Synthetic Aperture Radar) displacement data during 2003–2020 to evaluate the effect of groundwater recharge after the termination of groundwater pumping. A method was proposed to merge InSAR time series of displacement derived from multiple satellites (ENVISAT, COSMO-SkyMed, TerraSAR-X, and Sentinel-1) to achieve a consistent, long-term continuous deformation. We found that previous groundwater depression cones in Taiyuan (Xizhang, Wanbailin, Wujiabao, and Xiayuan) have turned into groundwater recovery and the corresponding subsidence centers have switched to land uplift. The subsidence center of Xizhang, north of Taiyuan city, experienced a total subsidence of 749 mm by Aug 2003; it then turned into uplift with an amount of rebound of 9.2 % of previous subsidence by the end of 2020. In central area of Taiyuan, the cumulated subsidence is 1127 mm in Wanbailin, 1817 mm in Xiayuan, and 3343 mm in Wujiabao. Beginning in Aug 2010, they all turned into land uplift, with a rebound of 7.9 %, 4.8 % and 3.6 % of the previous subsidence in each center, respectively. An analysis of the correlation between groundwater level and ground displacement suggests that the ground uplift is related to the poro-elastic rebound mechanism in the porous aquifer system, which is caused by the rise in pore pressure with groundwater recovery, and the amount of subsidence/uplift is controlled by the stratigraphic properties. The adverse impacts on the built environment due to the rising groundwater level were discussed. The findings improve our understanding of anthropogenic ground deformation in complex urban aquifers influenced by groundwater pumping and recharge and provides essential information that can contribute to future groundwater management and groundwater-related hazard mitigation over the Taiyuan city.

Long-term Renal Function Changes Following Renal Denervation: A Multi-Site Safety Study

Long-term Renal Function Changes Following Renal Denervation: A Multi-Site Safety Study

The complex effects of modern oncogenic environments on the fitness, evolution and conservation of wildlife species.

Growing evidence indicates that human activities are causing cancer rates to rise in both human and wildlife populations. This is due to the inability of ancestral anti-cancer defences to cope with modern environmental risks. The evolutionary mismatch between modern oncogenic risks and evolved cancer defences has far-reaching effects on various biological aspects at different timeframes, demanding a comprehensive study of the biology and evolutionary ecology of the affected species. Firstly, the increased activation of anti-cancer defences leads to excessive energy expenditure, affecting other biological functions and potentially causing health issues like autoimmune diseases. Secondly, tumorigenesis itself can impact important fitness-related parameters such as competitiveness, predator evasion, resistance to parasites, and dispersal capacity. Thirdly, rising cancer risks can influence the species' life-history traits, often favoring early reproduction to offset fitness costs associated with cancer. However, this strategy has its limits, and it may not ensure the sustainability of the species if cancer risks continue to rise. Lastly, some species may evolve additional anti-cancer defences, with uncertain consequences for their biology and future evolutionary path. In summary, we argue that the effects of increased exposure to cancer-causing substances on wildlife are complex, ranging from immediate responses to long-term evolutionary changes. Understanding these processes, especially in the context of conservation biology, is urgently needed.

The rise of biogenic silicon cycling and microbial silicification promoted Mesoproterozoic chert deposition

The silicon (Si) cycle is intimately interlinked with other biogeochemical cycles (e.g., carbon and nitrogen) and plays an important role in regulating long-term global climate change and biotic evolution in Earth's history. The abundance of cherts in Mesoproterozoic shallow-marine carbonates implies unique environmental conditions for silica precipitation, but the driving mechanism behind the Si cycle in Mesoproterozoic oceans remains unclear. In this paper, we report an integrated study of the cherts from the ∼1.48 Ga Wumishan Formation of North China. The Wumishan cherts predominantly consist of microquartz (∼90%), with some silica-replaced carbonate (∼5%) and minor pyrite (∼1%) grains, indicating that the cherts were largely formed through primary silica precipitation. High germanium/silicon molar ratios (Ge/Si = 0.71–19.1 μmol/mol; mean = 8.83) and positive europium anomalies (Eu/Eu* = 0.41–2.42; mean = 1.41) of the cherts suggest a considerable contribution from hydrothermally derived Si. Diverse microbial components, including organic-rich filaments, EPS (extracellular polymeric substances) relics, mat fragments and picocyanobacteria fossils, are observed in the Wumishan cherts. These components, together with abundant organominerals resulted from the interactions of microbes and dSi in ambient environments, imply that microbial activities played critical roles in silica deposition. The Si liberated from degraded EPS or EPS-Si complex may have locally increased the dSi concentrations and changed chemical conditions in the substrate and pore-waters, promoting silica precipitation. Given that picocyanobacteria and some other prokaryotes can accumulate significant amounts of silica in their cells and EPS, biogenic silica from decomposed microbial biomass may have exerted an important influence on silica precipitation in shallow-marine environments of the Mesoproterozoic ocean.

Will fire-smart landscape management buffer the effects of climate and land-use changes on fire regimes?

BackgroundLong-term farmland abandonment has increased fuel build-up in many Euro-Mediterranean mountainous regions. The high fuel hazard in these landscapes, combined with ongoing climate change, is increasing the frequency of extreme wildfires, thus altering contemporary fire regimes. Mitigating the loss of the landscape’s capacity to regulate large and intense fires is crucial to prevent future harmful effects of fires. As such, effective strategies to manage these fire-prone landscapes are needed. Yet, further understanding of their performance under global change scenarios is required. This study assessed the effects of fire-smart management strategies on future landscape dynamics, fire regulation capacity (FRC), and fire regime in a Mediterranean fire-prone mountainous landscape in Portugal (30,650 ha) undergoing long-term land abandonment and climate change scenarios. For that, we applied the LANDIS-II model under climate change scenarios (RCP 4.5 and 8.5) and long-term farmland abandonment (2020–2050) according to three fire-smart management strategies focused on fire prevention compared with a business-as-usual (BAU) strategy based on fire suppression.ResultsFuture fire activity and land dynamics resulted in changes that fostered landscape heterogeneity and fragmentation and favoured fire-adapted forests and agroforestry systems while decreasing the dominance of shrublands and croplands. FRC decreased over time, particularly under RCP 8.5 and the BAU strategy. In turn, fire-smart strategies better prevented large and intense fires than the BAU strategy, but their effectiveness decreased under RCP 8.5. The loss of FRC resulted in increased burned area and fire frequency, which predicts a shift from contemporary fire regimes but more markedly under RCP 8.5 and in the BAU strategy.ConclusionsFire-smart strategies outperformed BAU in averting current fire regime intensification. Merging forest- and silvopasture-based management is the most promising approach in taming the effects of climate and farmland abandonment on future fire activity. Our study underlines that planning and management policies in fire-prone Mediterranean mountain landscapes must integrate fire-smart strategies to decrease landscape fuel hazard and buffer the impact of global change on future fire regimes.