Possible Effects Of Climate Change Research Articles

An appraisal of seasonal precipitation dynamics over the North‐West Himalayan region under future warming scenarios

ABSTRACTIn the context of widely reported climate change over the mountainous region, the present work addresses the notable changes in the seasonal precipitation dynamics over the NWH region under two different future warming scenarios [socioeconomic pathway 245 (SSP245) and socio economic pathway 585 (SSP585)]. Using three coupled climate models which participated in the Climate Model Inter‐comparison Project Phase 6 (CMIP6), we focus on the alterations of the spatio‐temporal pattern of solid and liquid precipitation in respective seasons under future warming (2066–2100) scenarios with respect to the historical time period (1981–2014). Intercomparative validation of the CMIP6 data sets has been carried out against the GPCP and ERA‐5 reanalysis datasets where the multimodel mean (MMM) product has performed well (r value = 0.63) compared with the individual model outputs in the historical scenario for last 35 years (1981–2014). Therefore, MMM has been used for analysis. Statistically robust K–S test suggests a remarkable variation in the cumulative distribution of the precipitation across the NWH region at 95% confidence level in both of the future warming scenarios as compared with the historical time period. Furthermore, significant increase in the JJAS rainfall (~25–30%) and decrease in the DJF snowfall (~20–25%) has been observed for ssp585 scenario whereas no significant results are noted under ssp245 scenario. Remarkable variations in the surface temperature distribution, large scale wind circulation pattern and mesoscale hydrometeorological balance under the warmest scenario (SSP585) elucidate the reason behind the noteworthy changes in the precipitation dynamics reflected from the normalized precipitation index (NPI) and changes in annual cycle and therefore illustrates the possibility of more extreme precipitation years in future. The overall investigation reflects the possible effect of climate change over the NWH region pertaining to the dynamics of the South West Monsoon and Western Disturbances.

A 15-year long assessment of cold hardiness of apricot flower buds and flowers during the blooming period

Long-term examinations are important for accurately dissecting the genotypic and environmental factors of and for predicting the possible impacts of climate change on quantitative traits, such as the frost tolerance of apricot generative organs during the floral developmental period. In our experimental work the cold hardiness of flower buds and flowers of three apricot cultivars [‘Ceglédi bíborkajszi’ (CBK), ‘Gönci magyar kajszi’ (GMK) and ‘Rózsakajszi C.1406’ (RK)] was studied systematically in different phenological stages, applying a standardised artificial freezing test protocol on samples collected from the orchard during a period of 15 consecutive years. Based on the results, both the genotypes and the years were highly significant components of frost tolerance; at the early phases the greater effect of years, while at the later stages that of the genotypes were detected. RK was frost tolerant and more stable across the years, while CBK was the most frost sensitive, which was accompanied by a significantly higher sensitivity to seasonal differences. Positive correlation was found between the starting time of blooming and frost tolerance of flowers, the significance of which intensified with the frost sensitivity of the apricot genotype. Significant associations were identified between various meteorological parameters of the 8-month period prevailing flowering and frost tolerance of apricot flowers during blooming. Possible effects of climate change on the local weather conditions were also detected with significant impacts on the phenological processes of floral buds, on the timing of flowering and on frost tolerance.

Medium-Term Increases in Ambient Grass Pollen Between 1994-1999 and 2016-2020 in a Subtropical Climate Zone.

Grass pollen is the major outdoor trigger of allergic respiratory diseases. Climate change is influencing pollen seasonality in Northern Hemisphere temperate regions, but many aspects of the effects on grass pollen remain unclear. Carbon dioxide and temperature rises could increase the distribution of subtropical grasses, however, medium term shifts in grass pollen in subtropical climates have not yet been analysed. This study investigates changes in grass pollen aerobiology in a subtropical city of Brisbane, Australia, between the two available monitoring periods, 1994-1999 and 2016-2020. Potential drivers of pollen change were examined including weather and satellite-derived vegetation indicators. The magnitude of the seasonal pollen index for grass showed almost a three-fold increase for 2016-2020 over 1994-1999. The number and proportion of high and extreme grass pollen days in the recent period increased compared to earlier monitoring. Statistically significant changes were also identified for distributions of CO2, satellite-derived seasonal vegetation health indices, and daily maximum temperatures, but not for minimum temperatures, daily rainfall, or seasonal fraction of green groundcover. Quarterly grass pollen levels were correlated with corresponding vegetation health indices, and with green groundcover fraction, suggesting that seasonal-scale plant health was higher in the latter period. The magnitude of grass pollen exposure in the subtropical region of Brisbane has increased markedly in the recent past, posing an increased environmental health threat. This study suggests the need for continuous pollen monitoring to track and respond to the possible effects of climate change on grass pollen loads.

Early stages of anchovy: abundance, variability and larval condition at the fixed coastal station EPEA between 2000-2017

Densities of eggs and larvae of Engraulis anchoita and the nutritional condition of larvae were analyzed in the fixed sampling station (EPEA) in the period 2000-2017. These variables were analyzed seasonally and trends over time were determined. Ichthyoplankton samples were collected by oblique trawls using Bongo nets with 300 μm of pore mesh and fixed with formaldehyde 5% in seawater. Six morphometric variables were measured to estimate the nutritional condition of larvae. The developmental stage of each specimen was also determined. The highest mean value of egg density was detected in the October-December period, with a secondary mode in August, followed by one in March. Larval density presented a mode in October. Autumn and spring were the most favorable seasons for larval condition while winter proved to be the least favorable one. An increase in food availability during autumn and spring due to primary and secondary production peaks could explain the high nutritional condition and growth values observed in these seasons at the EPEA. No changes in trends of variables over time were detected. The integrated study of density and nutritional condition of E. anchoita larvae allows the determination of favorable breeding periods for the species, while the continuation of the long term study will allow evaluating possible effects of climate change in the early life stages of this species.

Evaluating the effect of the statistical downscaling method on monthly precipitation estimates of global climate models

<p>Researches to foresee the possible effects of climate change on the environment and living beings for taking necessary precautions on time have increased in recent years. In the improvement of these studies, especially the reduction of estimation errors by downscaling the outputs of global climate models played an important role. In this study, a model that can predict monthly precipitation amounts in the future by using downscaling methods in different global climate models were applied in Antakya district of Hatay province, and the model results were evaluated. The predictive parameters for global climate models were determined using downscaling methods by applying correlation analysis for the study area. As a result of this analysis, it was seen that the air temperature and specific humidity values at the pressure level of 925 hPa and the geopotential height value at the 300 hPa pressure level had the best correlation for the years 1970-2005. The usability of three different global climate models (CanESM2, GISS-E2H, and CSIRO Mk 3-6-0) for the forecast of future rainfall in the Antakya district of Hatay province was investigated using multiple linear regression analysis, one of the downscaling methods. As a result of the statistical analysis, it was seen that the use of the downscaling method increased the accuracy of all prediction models.</p>

Modeling Climate Change Impact on the Streamflow in the Upper Wabe Bridge Watershed in Wabe Shebele River Basin, Ethiopia

Climate change affects the availability of water resources by altering the pattern and magnitude of precipitation, temperature, and streamflow. The projection of climate change impact on the streamflow is used to identify the level of changes and desirable intervention measures. In this research, Soil and Water Assessment Tool (SWAT) model and the regional circulation model (RCM) outputs of CORDEX Africa climate model associated with mid and high-level Representative Concentration Pathways (RCP4.5 and RCP8.5) climate scenarios were used to evaluate the change in streamflow in two future projection scenarios (2041-2070 and 2071-2099). The study is directed to the Upper Wabe Bridge watershed found in the Wabe Shebele basin, Ethiopia. The result shows an increase in mean temperature by 3.46 and 5.15°C for RCP4.5; and 4.78 and 5.88°C for RCP8.5 in mid and long-term periods, respectively. The study also confirmed an increasing trend in annual precipitation by +26.3 and +31.85% for RCP4.5 and RCP8.5 climate scenarios, respectively, at the end of 21st century. In Kiremt (rainy) season precipitation shows an increasing trend by +44.28% and +59.34% for RCP4.5 and RCP8.5 climate scenarios, respectively, but Bega (dry) season show decreasing trend. The future projected annual streamflow shows increase trends under both climate scenarios in both projection periods. The mean seasonally streamflow decreases in the Belg (short rainy) season by -10.91% and increases in the Kiremt (rainy) season by 17.4%. Hence, the increment trend in streamflow during the Kiremt season will have the utmost significance for the requirement of storage and rainwater harvesting structures for irrigation development during dry season. Therefore, incorporating the possible effect of climate change is vital during water resources planning and development.

Establishment of the Baseline for the IWRM in the Ecuadorian Andean Basins: Land Use Change, Water Recharge, Meteorological Forecast and Hydrological Modeling

This study was conducted in the Zamora Huayco (ZH) river basin, located in the inter-Andean region of southern Ecuador. The objective was to describe, through land use/land cover change (LUCC), the natural physical processes under current conditions and to project them to 2029. Moreover, temperature and precipitation forecasts were estimated to detail possible effects of climate change. Using remote sensing techniques, satellite images were processed to prepare a projection to 2029. Water recharge was estimated considering the effects of slope, groundcover, and soil texture. Flash floods were estimated using lumped models, concatenating the information to HEC RAS. Water availability was estimated with a semi-distributed hydrological model (SWAT). Precipitation and temperature data were forecasted using autoregressive and exponential smoothing models. Under the forecast, forest and shrub covers show a growth of 6.6%, water recharge projects an increase of 7.16%. Flood flows suffer a reduction of up to 16.54%, and the flow regime with a 90% of probability of exceedance is 1.85% (7.72 l/s) higher for 2029 than for the 2019 scenario, so an improvement in flow regulation is evident. Forecasts show an increase in average temperature of 0.11 °C and 15.63% in extreme rainfall by 2029. Therefore, intervention strategies in Andean basins should be supported by prospective studies that use these key variables of the system for an integrated management of water resources.

Adaptation of Climate Change to Vulnerability of Raw Water Availability in Bantaeng, South Sulawesi

Various processes triggering global climate change and climate change have been accepted by many parties as a necessity characterized by global warming, with a direct impact on the hydrological cycle, so that climate change is believed to have a real impact on water resources. Taking into account the possible consequences of climate change, it will be extremely important to examine how fluctuation in temperature and rainfall pattern shift will affect the water supply system. With this climate change, it will lead to vulnerability to the availability of raw water. The vulnerability referred to in Bantaeng was simply determined by three factors that were considered dominant, namely water needs, water sources, and community welfare. The analysis results showed that there was a higher risk increase which was influenced by hydrogeological conditions related to groundwater potential. Optimal groundwater management was expected to contribute as an adaptation effort to climate change risks to water sources.

Regeneration of tropical montane cloud forests increases water yield in the Brazilian Atlantic Forest

AbstractTropical montane cloud forests (TMCF) have paramount importance with regards to hydrological and ecological functions. Despite such importance in terms of water provision, they are one of the most endangered ecosystems on the planet. One important topic that is still unclear is related to TMCF regeneration: can it recover the hydrological function of such critical ecosystems? In the present paper, the hydrological effects of the natural regeneration of TMCF were examined. We selected three catchments with different degrees of TMCF, and we examined the relationship between the amount of TMCF over time and hydrological variables such as water yields and baseflow using a time series (1984–2011). Our results suggest that the increase in TMCF cover can contribute to increases in water yield. This pattern was found in a catchment with an increase of approximately 20% of forest cover. In catchments with TMCF increase lower than this threshold, water yield and flow path were influenced by hydroclimatic variables such as air temperature and rainfall. The effect of the reduction in water yield, in accordance with the increase in mean temperature, sheds light on possible consequences of climate change on ecosystem services produced in foggy environments. In light of these findings, aiming to increase the water yield, we recommend that regions frequently affected by fog are prioritized for forest restoration or conservation. To ensure significant effects, regeneration and/or successional development of TMCF has to reach at least 20% of a catchment area.

Influence of Carbonate-Flysch Contact and Groundwater Dynamics on the Occurrence of Geohazards in Istria, Croatia

This research focuses on the analysis of soil-water interaction at the carbonate-flysch contact on the Istrian peninsula in Croatia. As a result of the interaction of surface and groundwater and the position of flysch and carbonate rocks in the geotechnical profile, two problems occur in the study area: numerous instabilities and the occasionally high turbidity of drinking water. As an example, the St. Ivan spring was considered. The paper presents a complex mechanism of groundwater circulation in geological structures at carbonate-flysch contacts, differences in runoff through karst aquifers and flysch rocks during heavy rainfall under current and predicted (climate change) conditions, and the mentioned geohazards as a result of extreme precipitation. The analyses carried out showed the decisive influence of the existing geological structure on the dynamics of infiltration and precipitation runoff, as well as the risks of pronounced spring water turbidity and instability events. The main drivers of these geohazards are continuous long-term precipitation for landslides and intense daily precipitation for turbidity. Possible consequences of climate change are the increase in precipitation intensity, amount and higher variation, which subsequently brings risks such as the increase in maximum runoff, i.e., the expected more frequent occurrence of high turbidity and the more frequent occurrence of higher cumulative precipitation triggering instabilities in the area.

Decadal climate sensitivity of contouritic sedimentation in a dynamically coupled ice-ocean-sediment model of the North Atlantic

Ocean sediment drifts contain important information about past bottom currents but a direct link between the study of sedimentary archives and ocean dynamics is not always possible. To close this gap for the North Atlantic, we set up a new coupled Ice-Ocean-Sediment Model of the N. Atlantic - Arctic region. In order to evaluate the potential dynamics of the model, we conducted decadal sensitivity experiments. In our model contouritic sedimentation shows a significant sensitivity towards climate variability for most of the contourite drift locations in the model domain. We observe a general decrease of sedimentation rates during warm conditions with decreasing atmospheric and oceanic gradients and an extensive increase of sedimentation rates during cold conditions with respective increased gradients. We can relate these results to changes in the dominant bottom circulation supplying deep water masses to the contourite sites under different climate conditions. A better understanding of northern deep water pathways in the Atlantic Meridional Overturning Circulation (AMOC) is crucial for evaluating possible consequences of climate change in the ocean.

Microbial activity in alpine soils under climate change

Soil enzymatic activity was assessed in the Stelvio Pass area (Italian Central Alps) aiming to define the possible effects of climate change on microbial functioning. Two sites at two different elevations were chosen, a subalpine (2239 m) and an alpine belt (2604–2624 m), with mean annual air temperature differing by almost 3 °C, coherent with the worst future warming scenario (RCP 8.5) by 2100. The lower altitude site may represent a proxy of the potential future situation at higher altitude after the upward shift of subalpine vegetation due to climate change. Additionally, hexagonal open top chambers (OTCs) were installed at the upper site, to passively increase by about 2 °C the summer inner temperature to simulate short term effects of warming before the vegetation shift takes place. Soil physicochemical properties and the bacterial and fungal abundances of the above samples were also considered. The subalpine soils showed a higher microbial activity, especially for hydrolytic enzymes, higher carbon, ammonium and hydrogen (p < 0.001) contents, and a slightly higher PO4 content (p < 0.05) than alpine soils. Bacterial abundance was higher than fungal abundance, both for alpine and subalpine soils. On the other hand, the short term effect, which increased the mean soil temperature during the peak of the growing season in the OTC, showed to induce scarcely significant differences for edaphic parameters and microbial biomass content among the warmed and control plots. Using the manipulative warming experiments, we demonstrated that warming is able to change the enzyme activity starting from colder and higher altitude sites, known to be more vulnerable to the rising temperatures associated with climate change. Although five-years of experimental warming does not allow us to make bold conclusions, it appeared that warming-induced upwards vegetation shift might induce more substantial changes in enzymatic activities than the short-term effects, in the present vegetation context.

Implications of Health Research and Climate Change Mitigation on the Transmission of Influenza Viruses in Africa

As the climate of the earth changes rapidly, its devastating effects on human health becomes more evident. Possible effects of climate change on human health include higher rates of respiratory diseases, increased prevalence of vector -borne, zoonotic and waterborne diseases, food and water scarcity, as well as malnutrition. Worsened conditions are predicted in Africa primarily due to the inadequacy of optimum public health systems and climate mitigative controls. Addressing the implications of climate change mitigation and public health research could have substantial benefits to human health, particularly in the transmission of infectious diseases such as influenza. This review aims to explore available literature on the current effects of climate cha nge in Africa and how it influences the incidence and prevalence of influenza, thereafter making recommendations to ameliorate current conditions by encouraging interdisciplinary collaborations.

North Atlantic Oscillation and fisheries management during global climate change

The North Atlantic Oscillation (NAO) is the most important large-scale climatic oscillation affecting the North Atlantic region. The variability introduced by the NAO affects many meteorological parameters, including wind speed and direction, and differences in air temperature and rainfall, particularly during the boreal winter. The NAO is also known to affect the ocean by changing heat content, sea surface temperature, gyre circulation, mixed layer depth, salinity, high-latitude deep water formation, and sea ice cover. Consequently, the NAO has been widely used to analyze the variability of marine ecosystems. Several researchers found that fishery resources were teleconnected with the NAO variability, resulting in a significant relationship between this climatic oscillation and fishery yields. More precisely, the NAO affects the target species abundance, recruitment, catchability, and body condition. These effects can be cumulative over time and act synergistically. In this study, the available information about this topic is reviewed, and the importance of the NAO as a large-scale climatic oscillation in fisheries management is discussed using an ecosystem approach. We also discuss the possible effects of climate change on Atlantic and Mediterranean fisheries if this change were to affect the NAO pattern.

Assessing the Present and Future Habitat Suitability of Caligus rogercresseyi (Boxshall and Bravo, 2000) for Salmon Farming in Southern Chile.

The sea louse (Caligus rogercresseyi) is the most relevant parasite for the farmed salmon industry in Chile, the second largest producer worldwide. Although spatial patterns of C. rogercresseyi have been addressed from data obtained from established monitoring and surveillance programs, studies on its spatial ecology are limited. A wide geographic distribution of C. rogercresseyi is presumed in Chile; however, how this species could potentially be distributed in space is unknown. Our study presents an analysis of the habitat suitability for C. rogercresseyi in the entire area occupied by marine sites of salmon farms in Chile. Habitat suitability modeling was used to explore the likelihood of species spatial occurrence based on environmental characteristics. Due to the expanding salmon industry in southern Chile, we studied C. rogercresseyi habitat suitability models for present (average of 2005–2010) and two future projections (2050 and 2100) under different climate change scenarios. Models were constructed with the maxent algorithm using a large database of spatial C. rogercresseyi occurrences from the Chilean fisheries health authority and included 23 environmental variables obtained from the Ocean Rasters for Analysis of Climate and Environment (Bio-ORACLE). Habitat suitability models indicated that water temperature, water salinity, and current velocity of waters were the most important characteristics limiting C. rogercresseyi distribution in southern Chile. Habitat suitability models for current climate indicated a heterogeneous pattern with C. rogercresseyi being present in waters with temperature range 12.12–7.08°C (sd = 0.65), salinity range 33.7–25.5 pss (sd = 1.73), and current water velocity range 0.23–0.01 m−1 (sd = 0.02). Predictions for future projections in year 2050 and year 2100 suggest new clumped dispersion of the environmental conditions for C. rogercresseyi establishment. Our results suggest complexity and a wide dispersion of the biogeographic distribution of the C. rogercresseyi habitat suitability with potential implications for control strategies and environmental issues for salmon farming in Chile. Further investigations are required into C. rogercresseyi distribution in southern Chile considering the possible effect of climate change.

Modelado de distribución de especies en los bosques de los andes meridionales

La elevada biodiversidad junto con una gran variedad de ecosistemas convierten a la Cordillera de los Andes es una de las regiones de mayor diversidad ambiental del mundo, donde se encuentran los rangos más extremos de tipos de paisajes, clima y formaciones forestales de la Tierra, un área adecuada para estudiar los posibles efectos del cambio climático sobre la distribución espacial de las formaciones forestales.&#x0D; Para ello resulta imprescindible entender los efectos de cambio climático en la zona, dónde las observaciones climáticas indican diferentes escenarios climáticos en el futuro, para un periodo de tiempo actual y para el periodo 2040-2069, con variaciones de las temperaturas y precipitaciones. Se analiza la distribución de los bosques a través de modelado predictivo con el método de máxima entropía de MaxEnt. Los resultados señalan que la mayoría de las formaciones forestales de los bosques andinos analizados tendrán previsiblemente problemas importantes en un futuro próximo, consecuencia de la pérdida de idoneidad climática en el área actual de distribución y del cambio geográfico de las áreas potencialmente adecuadas en el futuro como reflejan los resultados.&#x0D; Palabras clave: biodiversidad, modelos de distribución de especies, cambio climático, bosques, máxima entropía. The high biodiversity along with a great variety of ecosystems turn Andes Mountain one of the regions of greater environmental diversity of the world, where are the most extreme ranges of types of landscapes, climate and forest formations of the Earth, an area suitable for studying the possible effects of climate change on the spatial distribution of forest formations.&#x0D; For this it is essential to understand the effects of climate change in the area, where climate observations indicate different climate scenarios in the future, for a current time period and for the period 2040-2069, with variations in temperatures and precipitation. The distribution of forests through predictive modelling is analyzed using MaxEnt’s maximum entropy method. The results indicate that most of the forest formations in the Andean forests analysed are expected to face significant problems in the near future, as a result of the loss of climate suitability in the current area of distribution and the geographic change of potentially suitable areas in the future as reflected in the results.&#x0D; Keywords: biodiversity, species distribution models, climate change, forests, maximum entropy

Future projections of water level and thermal regime changes of a multipurpose subtropical reservoir (Sao Paulo, Brazil)

The increase in global air temperatures as well as variability in rainfall shifts due to climate change has been affecting the dynamics of water level fluctuations and thermal regimes in lakes and reservoirs. It is expected that at the end of this decade, such impacts will be even more noticeable and may harm the inland waters use. However, little is known about the possible consequences of climate change in multipurpose subtropical reservoirs. Using data generated by a regionalized climate model (RCM) as input to a simple hydrological model and a one-dimensional vertical hydrodynamic model, we forecast potential changes in the Itupararanga reservoir, São Paulo, Brazil, in an exemplary time period (2028–2030) in the next decade. Two Representative Concentration Pathway (RCP) scenarios were considered: an optimistic one corresponding to a CO2 increase of about 650 ppm (RCP 4.5) and a pessimistic scenario where CO2 exceeds 1000 ppm in 2100 (RCP 8.5). We found a significant reduction in the reservoir water level for both scenarios of 35% compared to current conditions. The surface water temperature is expected to increase (+0.6 °C); on the other hand, there would be a cooling of the hypolimnion (RCP 4.5 =-0.3 °C; RCP 8.5 = −1.2 °C). Another consequence is an increase of the duration of stratification periods that would start earlier in the dry period (between July and August), as well as the intensification of the stability of the water column (+43% compared to current conditions) and a deepening of the thermocline. The hydrodynamic modeling results suggest that the water level drop may threaten the reservoir multiple uses, in particular drinking water supply and power generation. Furthermore, the heating of surface water layers and increase of the number of stratified days and thermal stability can have negative impacts on water quality.

Major drivers of land degradation risk in Western Serbia: Current trends and future scenarios

Land degradation and desertification (LDD) is one of the greatest ecological challenges of today, with climate change resulting from anthropogenic factors a major cause of it. Recent projections of LDD in the Mediterranean region indicate a gradual widening of arid areas due to increased aridity and global warming by the end of the 21st century. Therefore, this study used the MEDALUS method to identify sensitivity to LDD in Western Serbia between 1986 and 2005 and to assess possible effects of climate change (RCP4.5 and RCP8.5 scenarios) on land degradation processes by the end of the 21st century. Likewise, analysis of possible major drivers of degradation was conducted using principal component analysis (PCA) and multiple linear regression analysis (MLRA). The study revealed that degradation processes in the study area were found to be most influenced by anthropogenic drivers (34.4%), less so by natural/anthropogenic ones (23.5%), and least by natural factors (20.1%). Results also showed that critical areas of LDD susceptibility account for nearly 37% of the study area, transitional areas cover 35%, while 27% constitutes potentially safe areas. Additionally, critical areas were projected to expand by 33.6% (RCP4.5) and 51.7% (RCP8.5) by 2100 as a result of predicted temperature increases and a reduction in precipitation in the study area. This study also revealed that the Standardised Precipitation-Evapotranspiration Index (SPEI) better explains the impact of climate change on LDD than other indices, bearing in mind the capacity of this index to detect temporal oscillations in drought in the context of climate change, and it is therefore a reliable climate parameter for this method.

Long-term growth of three sympatric Dryopteris fern species shows the accumulation of climatic effects over 2 years because of organ preformation

We hypothesized that yearly response of plant growth to seasonal weather conditions would provide insight into the biogeographic status of three closely related and sympatric Dryopteris fern species and elucidate their potential future performance in conditions of climate change. In a 9-year experiment, we surveyed the yearly performance of 108 ex situ pre-grown sporophytes of D. carthusiana, D. dilatata, and D. expansa in six forests in Estonia. We used multi-factorial models to assess species-specific responses of frond traits and population parameters to seasonal temperature, precipitation, and snow cover, and also considered the effects of continentality and overstory density. Frond length was highly limited by plant age, and even the 11-year-old plants did not reach their mature size. The number of fronds stabilized already in the first few years. Climate effects on leaf traits accumulated over 2 years, as their growth benefited from the abundant precipitation during two growing seasons and the presence of dry cold winters. Milder climate near the coast and semi-open overstory provided some extra support for the growth. Species-specific effects were rare. The species’ responses to habitat and climate effects only partly mirrored their present biogeographic distribution. Evidently, possible effects of climate change might go unnoticed for decades in these ferns since it would be mitigated by (1) their slow ontogenesis, (2) organ preformation during preceding year(s), and (3) region-specific and habitat-specific effects of environmental conditions.

Dendrochronological Indication of Phyllophages’ Outbreaks by Larch Radial Growth in the Forest-steppe Zone of the Republic of Tyva

One of the possible consequences of climate change is a change in the demographic dynamics of phyllophagous insects. For a retrospective analysis of this dynamics, tree rings are used, especially in regions with limited documentary data. Due to the complex nature of the factors determining tree growth, in order to more clearly identify pest-induced defoliation in tree-ring chronologies one suppress the climatic signal expressed directly or indirectly (through chronologies of non-host tree species). However, in South Siberia, the choice of non-host species is hampered by the wide distribution of polyphages, like the gypsy moth (Lymantria dispar Linnaeus) and the Siberian silk moth (Dendrolimus sibiricus Tsch.). Therefore, the analysis of pest outbreaks in larch forests of the Republic of Tuva low mountains was started by removing the climatic response based on instrumental data, identifying depressions in the residual time-series of individual tree radial growth at several sites, and comparing them with available actual data on forest damage by phyllofages. Dendroclimatic analysis showed that the model including the precipitation-to-maximum-temperature ratio for June-September of the previous season and June of the current year, i.e. the degree of aridity during the previous and current growing season, describes 43.7% of the regional variation in the growth of Siberian larch (Larix sibirica Ledeb.). After removal of this component, several periods of larch growth depression were revealed during confirmed outbreaks of the Siberian silk moth, gypsy moth, and larch tortrix (Zeiraphera diniana Gn.). The use of documented data over 1998–2016 allowed to clarify the threshold values of the portion of affected trees for intensities of the growth depression ranging 1–1.5 standard deviations, providing the required reliability of the outbreak reconstruction. The dependence of the spatio-temporal patterns of growth depression on the pest species was revealed, reflecting their migration in the affected area. It has been shown that growth depressions may be delayed compared with the actual damage by pests due to the long recovery after recurrent defoliation.