The ability to withstand short-term heat shocks and long-term elevated ambient temperatures suggests different sensitivity to future climatic changes for two sympatric Mediterranean land snail species, Theba pisana and Xeropicta derbentina (Helicoidea).

Difference in ozone uptake in grassland species between open-top chambers and ambient air

Effects of elevated CO 2 and drought on wheat: testing crop simulation models for different experimental and climatic conditions

Open top chambers (OTCs) are a popular method for studying the biological effects of climate change through passive heating, but their effects on biotic interactions are poorly understood, especially for pollination. Here we use the subalpine plants Delphinium nuttallianum and Potentilla pulcherrima to examine the possibility that the effects of OTCs on plant reproduction are not the result of warming but rather OTCs acting as barriers to pollinator movement. Pollinator observations were conducted and stigmas collected from plants inside and outside of OTCs in a meadow in the Rocky Mountains of Colorado, USA. Very few visitors were observed inside of OTCs, which led to severe reductions in visitation rates, by 92% in Delphinium and 85% in Potentilla. The number of conspecific pollen grains on stigmas was 73% lower in OTCs for Delphinium but not Potentilla, likely because it is capable of autogamous self-pollination. This study clearly shows that OTCs can reduce animal pollination, which is also likely to reduce plant reproductive output of outcrossing plants via decreases in the quantity or quality of pollen. OTCs may therefore confound effects of warming on plant reproduction with pollination effects. Although the unintended effects of OTCs on abiotic conditions are well-studied, this study highlights that their effects on biotic interactions require further investigation.

The projected adverse impact of climate change on food grain production of tropical and subtropical latitudes necessitates the development of suitable agro-adaptations. We used open top chamber (OTC) experimental facility and simulation analysis to study the effect of elevated [CO2] with varying nutrients management on rice grain yield and to evaluate planting time adjustment as adaptation to climate change. The OTC experiments with ambient [CO2] level ([CO2] ~390 ppm) and elevated [CO2] (25% higher than the ambient) using cultivar ‘Swarna sub1 (140–145 days)’ were conducted during wet season of the years 2011 and 2012 at West Medinipur, India. Using CERES model, we simulated rice grain yield for future climate scenario (A1B) during the years 2020 (2010–2039) and 2080 (2071–2099) at four selected locations of the subtropical India. The elevated [CO2] in OTC increased panicle number, but decreased filled grain number per panicle, 1000-grain weight and grain yield. The increasing [CO2] had smaller adverse impact for integrated nutrients management as compared with chemical fertiliser. The model simulated grain yield reduction of 6.1−13.0% during 2020 and 14.4 −25.0% during 2080 with rising temperature 1.6 and 4.6°C, respectively, compared with the base period (1961–1990). Early planting during 25 June to 25 July received closure favourable temperature and rainfall during the crop growing period, hence had better adaptation to the climate change. Increasing dose of integrated nutrients and early planting is expected to minimise the adverse impact of climate change on rice production of the subtropical India.

![Figure][1] In August 2009, the International Union of Physiological Sciences (IUPS) held its 36th Congress in Kyoto in the same convention centre where the historic Kyoto Protocol was drawn up 12 years earlier. The symbolism of this coincidence was not missed by Malcolm Gordon, the Chair of

Open‐top chambers (OTCs), widely used as field warming facilities, not only generate warming effects but also reduce water availability through the rain interception effect. While OTCs are extensively applied to explore the effects of warming on seedling recruitment which act as a fundamental driver of population dynamics, the potential experimental biases introduced by the rain interception effect remain largely unexplored. This knowledge gap raises concerns about the interpretation of warming experiments using OTC facilities. We conducted warming experiments in alpine meadows on the Tibetan Plateau using OTCs. Three treatments were applied: control (no OTC), warming alone (W, +2°C without OTC precipitation interception) and warming with decreased precipitation (WDP, +2°C with OTC precipitation interception). Focusing on 50 plant species across various functional groups, we disentangled the independent effects of warming and decreased precipitation caused by OTC interception on seedling emergence, survival and establishment. We applied structural equation modelling (SEM) to analyse the relationships between emergence timing, rate, survival and establishment success. Our study demonstrates that W and WDP treatments accelerated seedling emergence but decreased survival and establishment rates at the community level. The WDP reduced survival by 20% compared to W. The SEM analysis revealed that earlier emergence and higher emergence rates under W indirectly reduced establishment success, while WDP directly suppressed survival by limiting water availability. Furthermore, W increased the biomass of grasses and perennials, whereas WDP significantly reduced their biomass. In contrast, annuals and non‐grasses showed no significant response to either treatment. Synthesis and applications. The OTC‐induced precipitation reduction can overestimate the impacts of warming on seedling establishment success, with species and functional group‐specific responses. Therefore, interpreting data from OTC warming experiments requires careful consideration of precipitation interception effects. To mitigate this issue, future studies should optimize experimental designs to minimize precipitation interception, incorporating methods such as collecting and redistributing precipitation to better support seedling water availability. Furthermore, to enhance ecosystem resilience and support biodiversity in the context of climate change, conservation strategies should prioritize species and functional groups that are especially vulnerable to changes in warming and precipitation.

Health and vitality assessment of two common pine species in the context of climate change in southern Europe

How growth and morphology of wild plants are controlled by the relative air humidity is not sufficiently understood. The present study investigated long-term effects of contrasting air humidity levels on growth, physiology and distribution of woodland herbs and tree saplings. Major study aims were to examine (i) whether species of the forest floor vegetation require high air humidity for optimal growth, and (ii) if reductions of air humidity have negative consequences for the species of this environment. Air humidity was either manipulated in climate chambers or in open-top chambers in the field, or investigated in the natural climate of the forest floor. In both climate chamber and open-top chamber experiments, all investigated species were negatively affected when they were grown under reduced air humidity but ample soil moisture. An air humidity reduction of 45% in the climate chamber experiment resulted in a dry matter reduction of 40% in the woodland herb species and of 68% in the tree saplings. In the open-top chamber experiment, an air humidity reduction of 15% on the forest floor resulted in a biomass decrease of 25% to 30% in all investigated species.The results of the climate chamber and open-top chamber experiments were supported in the observatorial field study, in which the distribution of several woodland herb species was correlated with the air humidity regime. The results of the study show that the prevailing air humidity acts as a soil water-independent growth factor for the forest floor vegetation. Woodland herbs and tree saplings require for optimal growth and development sufficiently high air humidity. A decrease of air humidity as a result of gap formation, clear-cutting of forests, or in a drier climate with longer and more intense summer droughts might strongly threaten species of the forest floor vegetation.

The production and consumption of greenhouse gases (GHGs) in soils are largely regulated by biological processes. Increasing atmospheric CO2 may alter these processes, thereby affecting GHG emissions and their feedbacks to climate. Here, we used an open top chamber (OTC) experiment to examine the effects of elevated CO2 for ten years on soil GHG fluxes in a Quercus mongolica dominated system in northeastern China. Our results showed that elevated CO2 increased soil CO2 emissions, consistent with increased microbial biomass and the abundance of arbuscular mycorrhizal fungi and actinomycetes. Additionally, elevated CO2 increased CH4 uptake due to stimulated growth of methanotrophs. The seasonal mean soil N2O flux was not changed by elevated CO2, consistent with unchanged ammonia oxidizing bacteria, archaea and denitrifiers, which was probably due to large variations between the individual OTCs and with time. However, seasonal cumulative soil N2O emissions increased by 64.7% under elevated CO2. Our results also hinted that nitrification by ammonia oxidizing archaea was the major process of soil N2O emissions. In our study elevated CO2 increased soil GHG emissions and the cumulative global warming potential by 27.8%, causing an important positive feedback to climate change.

Ecosystem responses to current global climate change can be predicted through experimental climate simulations. One such simulation method is the open-top chamber (OTC). The effects of OTCs on environmental factors are potentially complex, and recognizing the numerous interactions among these factors is crucial for the proper use of chambers. We studied the effects of OTCs on microclimatic factors including ambient temperature, relative humidity, soil temperature, and soil moisture. Plant abundance responses were also assessed. Our study involved the construction of 20 OTCs (1 m in diameter and 0.75 m in height; made of clear acrylic plastic) and 20 control plots on substrates with and without Sphagnum moss, at post-fire and logging sites of the transitional mixedwood-boreal forest in the southern part of James Bay region, Quebec. Experimental trials were also conducted to test the effects of OTCs on snowmelt in the Montreal region. Our results suggest that OTC treatment is most evident in terms of increased daytime maximum temperatures (2°C to 3°C), and cooler (up to ∼2.4°C), drier (up to 10% volumetric moisture content) soils. Advanced thawing of the insulating snow cover and exposure of soil in the OTCs to low spring temperatures appeared to prolong soil freeze and result in cooler soils. Earlier snowmelt probably also led to earlier onset and overall increased evaporation of meltwater in the OTCs, leading to drier soils. Plant abundance responses to OTC treatment differed depending on plant species. Overall, open-top chambers provide an effective and simple method of climate change simulation, but it is highly advisable that the complex interactive effects, both desired and undesired, are well understood and appreciated before using OTCs for experimental climate simulation.

While the public continues to debate the reality of global warming, scientists should prepare to deal with the consequences of this very real phenomenon. Our planet has warmed by 0·13 ° C per decade since 1956, and will likely warm more rapidly in the decades to come (Intergovernmental Panel on Climate Change 2007). This global measure of thermal change belies the more pronounced and less predictable changes that are occurring on smaller scales (Walther et al . 2002). For example, the greater frequency and intensity of heat waves in many areas ranks among the more threatening aspects of anthropogenic climate change. Will acclimation or adaptation enable the persistence of populations that face such thermal stresses? And, if populations do persist, will their densities and compositions change radically? To answer these questions, we must understand a suite of phenomena, ranging from the mechanistic basis of thermotolerance to the demographic and ecological consequences of thermal plasticity (Angilletta 2009). This issue of Functional Ecology contains four papers that improve our understanding of these phenomena. To enhance your appreciation of this collection, I briefly highlight the significance of each paper while laying out the broader issues concerning the biological impacts of heat stress. During rapid warming, the performance of an organism depends on its capacity to protect and modify its cellular structures. Brief exposure to extreme heat often causes greater thermotolerance within hours, a phenomenon referred to as

Effects of global changes on biodiversity have been paid more and more attention world widely, and the open top chambers (OTCs) are the most common tools to study the effects of climatic warming on plant diversity. However, it remains unclear how flowers evolve under environmental changes, which could help us to understand the changes of plant diversity in the OTCs. We compared the insect diversity and pollen:ovule (P/O) ratio of eight outcrossing species with different life histories inside and outside the OTCs on the Qinghai-Tibet Plateau, to examine the effects induced by OTCs on the evolution of floral traits. In the OTCs, P/O ratio decreased in annuals, but increased in perennials, indicating an overall trend toward selfing in annuals. We found that the insect diversity differed significantly inside and outside the OTCS, with decreases of dipteran insects and bees. We concluded that changes of P/O ratio in the studied plant species might result from pollination failure, which might be the results of mismatch between flowering time and pollinator activities. We also suggested annuals might be in a more extinction risk than perennials in OTCs, if strong inbreeding depression occurs in these annual outcrossing plants.

The type and frequency of disturbances experienced by soil microbiomes is expected to increase given predicted global climate change scenarios and intensified anthropogenic pressures on ecosystems. While the direct effect of multiple disturbances to soil microbes has been explored in terms of function, their effect on the recovery of microbial community composition remains unclear. Here, we used soil microcosm experiments and multiple model disturbances to explore their short-term effect on the recovery of soil microbiota after identical or novel stresses. Soil microcosms were exposed to a heat shock to create an initial effect. Upon initial community recovery (25 days after stress), they were subjected to a second stress, either a heat or a cold shock, and they were monitored for additional 25 days. To carefully verify the bacterial response to the disturbances, we monitored changes in community composition throughout the experiment using 16S rRNA gene transcript amplicon sequencing. The application of a heat shock to soils with or without the initial heat shock resulted in similar successional dynamics, but these dynamics were faster in soils with a prior heat shock. The application of a cold shock had negligible effects on previously undisturbed soils but, in combination with an initial heat shock, caused the largest shift in the community composition. Our findings show that compounded perturbation affects bacterial community recovery by altering community structure and thus, the community’s response during succession. By altering dominance patterns, disturbance legacy affects the microbiome’s ability to recover from further perturbation within the 25 days studied. Our results highlight the need to consider the soil’s disturbance history in the development of soil management practices in order to maintain the system’s resilience.

Climate warming in the Antarctic tundra will affect locally dominant cryptogams. Being adapted to low temperatures and freezing, little is known about the response of the polar lichens’ primary photochemistry to warming and desiccation. Since 2008, we have monitored the ecophysiological responses of lichens to the future warming scenario during a long-term warming experiment through open top chambers (OTCs) on Fildes Peninsula. We studied the primary photochemical response (potential Fv/Fm and effective efficiency of photosystem II YPSII) of different lichen taxa and morphotypes under desiccation kinetics and heat shock experiments. As lichens grow slowly, to observe changes during warming we methodologically focused on carbon and nitrogen content as well as on the stable isotope ratios. Endemic Himantormia lugubris showed the strongest effect of long-term warming on primary photochemistry, where PSII activity occurred at a lower %RWC inside the OTCs, in addition to higher Fv/Fm values at 30 °C in the heat shock kinetic treatment. In contrast, Usnea aurantiaco-atra did not show any effect of long-term warming but was active at a thallus RWC lower than 10%. Both Cladonia species were most affected by water stress, with Cladonia aff. gracilis showing no significant differences in primary photochemical responses between the warming and the control but a high sensibility to water deficiency, where, at 60% thallus RWC, the photochemical parameters began to decrease. We detected species-specific responses not only to long-term warming, but also to desiccation. On the other hand, the carbon content did not vary significantly among the species or because of the passive warming treatment. Similarly, the nitrogen content showed non-significant variation; however, the C/N ratio was affected, with the strongest C/N decrease in Cladonia borealis. Our results suggest that Antarctic lichens can tolerate warming and high temperature better than desiccation and that climate change may affect these species if it is associated with a decrease in water availability.

Xeropicta derbentina (Krynicki, 1836), a native of Eastern Mediterranean Europe, was introduced to southeastern France during the 1940s and is now widely spread across Provence. In summer it aggregates on plants, making its populations clearly visible. However, its life cycle within the Mediterranean basin is poorly documented. While X. derbentina in its native area exhibits an annual life cycle, this species has been found in Provence to have a biennial life cycle. Moreover, in southeastern France, field studies within a restricted area show variations in demographic structure. In consequence, the life cycle of X. derbentina and the demographic patterns observed require clarification. Five populations with various demographic structures were studied over 1 year in the same location, i.e. under the same climatic conditions. The field study was complemented by laboratory observations on mating, egg-laying and hatching. Xeropicta derbentina appears to be a semelparous species, with an annual life cycle being found on four plots. The reproductive period begins at the end of summer and lasts until the beginning of winter. First egg-laying occurs within 1 week after mating and lasts up to 30 days. Hatching takes place 15–20 days after egg-laying. Xeropicta derbentina possesses multiple mating and egg-laying sessions, involving successive hatching. Populations are mainly characterized by two growth stages, the first in spring when newly-hatched snails evolve into juveniles, and the second in late summer when they reach maturity. However, on the highest density plot, a biennial life cycle is observed for some newly-hatched snails that show an interrupted growth during summer and evolve into juveniles only in the second autumn. Moreover, this life cycle not only varies among plots but also at a 1-year interval within plots. Hence, the life span of X. derbentina is between 12 and 20 months, but can be extended up to 30 months according to whether hatching occurs early or late and whether they survive the first and second winters. Xeropicta derbentina is thus able to have various growth speeds and life spans, and appears to switch from an annual life cycle to a biennial cycle in response to population density or climatic conditions.