scholarly journals Flowering phenology in alpine grassland strongly responds to shifts in snowmelt but weakly to summer drought

Alpine Botany ◽  
2021 ◽  
Author(s):  
Maria Vorkauf ◽  
Ansgar Kahmen ◽  
Christian Körner ◽  
Erika Hiltbrunner
Keyword(s):  
Biotic Interactions ◽  
Flowering Phenology ◽  
Alpine Plants ◽  
Alpine Grassland ◽  
Summer Drought ◽  
Phenological Cycle ◽  
The Alps ◽  
Delayed Flowering ◽  
Photoperiod Sensitive ◽  
Species Specific

AbstractAlpine plants complete their seasonal phenological cycle during two to three snow-free months. Under climate change, snowmelt advances and the risk of summer droughts increases. Yet, photoperiodism may prevent alpine plants from benefiting from an earlier start of the growing season. To identify the drivers of flowering phenology in the seven main species of an alpine grassland, we experimentally shifted the snowmelt date through snow manipulations, and excluded precipitation during summer. With “time-to-event” models, we analysed the beginning of main flowering with respect to temperature sums, time after snowmelt, and calendar day (photoperiod). We identified two phenology types: four species tracking snowmelt dates directly or with a certain lag set by temperature sums, including the dominant sedge Carex curvula, Anthoxanthum alpinum Helictotrichon versicolor, and Trifolium alpinum, and three species tracking photoperiod: Geum montanum, Leontodon helveticus and Potentilla aurea. Photoperiodism did not act as daylength threshold but rather modulated the thermal sums at flowering. Hence, photoperiod delayed flowering after earlier snowmelt. The grass A. alpinum was the only one of seven species that clearly responded to drought by earlier and longer flowering. The remarkably high importance of snowmelt dates for both phenology types suggests an earlier onset of flowering in a warmer climate, particularly for non-photoperiod-sensitive species, with an increasing risk for freezing damages and potential disruptions of biotic interactions in the most frequent type of alpine grassland across the Alps. Consequentially, the distinct microclimate and species-specific responses to photoperiod challenge temperature-only based projections of climate warming effects on alpine plant species.

scholarly journals Longitudinal zonation of larval Hydropsyche (Trichoptera: Hydropsychidae): abiotic environmental factors and biotic interactions behind the downstream sequence of Central European species

Hydrobiologia ◽  
2021 ◽  
Author(s):  
Márk Ficsór ◽  
Zoltán Csabai
Keyword(s):  
Environmental Factors ◽  
Biotic Interactions ◽  
Life Cycles ◽  
Longitudinal Distribution ◽  
Central European ◽  
European Species ◽  
Longitudinal Gradients ◽  
Species Specific ◽  
Behavioural Aspects ◽  
Abiotic Environmental Factors

AbstractThe aim of this review is to summarize the literature knowledge about how abiotic environmental factors and biotic interactions affect the sequentially overlapping longitudinal distribution of Central European species of the net-spinning freshwater caddisfly larvae of the genus Hydropsyche (Trichoptera: Hydropsychidae). In this relation, several physical and chemical parameters of water are discussed, as well as different species-specific traits, behavioural aspects and the interaction of coexisting species. Longitudinal gradients of river networks, especially annual temperature range, flow velocity and the particle size of suspended food material play a crucial role in forming the downstream succession of characteristic species, while increased levels of organic pollution, nutrients, salinity and heavy metals facilitates the presence of more tolerant ones. Several species-specific traits, such as respiration range, net-building frequency, head capsule size or optimal net-building velocity correlate with the position of a given species in the sequence. Coexistence of species with similar ecological demands in the overlapping zones of distribution is facilitated by differences in feeding and net-building habits, microhabitat preferences and staggering life cycles, but complicated at the same time by means of inter- and intraspecific territorial behaviour, such as fighting for the ownership of larval retreats or the practice of stridulation.

Temperature as a Proximate Factor in Orientation Behavior

1977 ◽  
Vol 34 (5) ◽  
pp. 734-739 ◽  
Author(s):  
William W. Reynolds
Keyword(s):  
Temperature Response ◽  
Biotic Interactions ◽  
Niche Differentiation ◽  
Behavioral Thermoregulation ◽  
Size Segregation ◽  
Ecological Value ◽  
Thermal Requirements ◽  
Prey Location ◽  
Proximate Factor ◽  
Species Specific

Temperature serves as a proximate factor (cue, guidepost, sign stimulus, or directive factor) affecting locomotor responses of fishes. Although temperature can also serve as an ultimate ecological factor, as in behavioral thermoregulation, nonthermal factors may in some cases provide the ultimate adaptive or ecological value of a temperature response; some examples are habitat selection, intraspecific size segregation, interspecific niche differentiation, isolating mechanisms, predator avoidance, prey location, escape reactions, and migrations (thermoperiodic, diel, seasonal, spawning). Conversely, nonthermal variables such as light intensity or water depth may act as accessory proximate factors in thermoregulation. In spawning migrations, thermal requirements of eggs and larvae may take precedence over the (often different) preferenda or optima of adults. Although thermal responses of fishes are largely innate and species specific, ontogenetic and other changes can occur. Since temperature can serve as an unconditioned reinforcer in operant conditioning, thermal responses are not limited to simple kineses or taxes. Nonthermal factors such as photoperiod, circadian rhythms, currents, social and biotic interactions, stresses, infections, or chemicals can affect thermal responses, and may account for some lack of conformity between laboratory preferenda and field distributions and behaviors. Key words: thermoregulation, orientation, preferendum, selection, preference, avoidance, behavior, temperature, fish, responses

scholarly journals Species-specific flowering phenology responses to experimental warming and drought alter herbaceous plant species overlap in a temperate–boreal forest community

2020 ◽  
Author(s):  
Karen E Rice ◽  
Rebecca A Montgomery ◽  
Artur Stefanski ◽  
Roy L Rich ◽  
Peter B Reich
Keyword(s):  
Species Interactions ◽  
Summer Rainfall ◽  
Flowering Phenology ◽  
Forest Community ◽  
Herbaceous Plant ◽  
Experimental Warming ◽  
Ambient Conditions ◽  
Climate Conditions ◽  
Herbaceous Perennials ◽  
Species Specific

Abstract Background and Aims Warmer temperatures and altered precipitation patterns are expected to continue to occur as the climate changes. How these changes will impact the flowering phenology of herbaceous perennials in northern forests is poorly understood but could have consequences for forest functioning and species interactions. Here, we examine the flowering phenology responses of five herbaceous perennials to experimental warming and reduced summer rainfall over 3 years. Methods This study is part of the B4WarmED experiment located at two sites in northern Minnesota, USA. Three levels of warming (ambient, +1.6 °C and +3.1 °C) were crossed with two rainfall manipulations (ambient and 27 % reduced growing season rainfall). Key Results We observed species-specific responses to the experimental treatments. Warming alone advanced flowering for four species. Most notably, the two autumn blooming species showed the strongest advance of flowering to warming. Reduced rainfall alone advanced flowering for one autumn blooming species and delayed flowering for the other, with no significant impact on the three early blooming species. Only one species, Solidago spp., showed an interactive response to warming and rainfall manipulation by advancing in +1.6 °C warming (regardless of rainfall manipulation) but not advancing in the warmest, driest treatment. Species-specific responses led to changes in temporal overlap between species. Most notably, the two autumn blooming species diverged significantly in their flowering timing. In ambient conditions, these two species flowered within the same week. In the warmest, driest treatment, flowering occurred over a month apart. Conclusions Herbaceous species may differ in how they respond to future climate conditions. Changes to phenology may lead to fewer resources for insects or a mismatch between plants and pollinators.

scholarly journals A framework to bridge scales in distribution modeling of soil microbiota

2020 ◽  
Vol 96 (5) ◽  
Author(s):  
Jonas J Lembrechts ◽  
L Broeders ◽  
J De Gruyter ◽  
D Radujković ◽  
I Ramirez-Rojas ◽  
...  
Keyword(s):  
Environmental Gradients ◽  
Spatial Scales ◽  
Biotic Interactions ◽  
Environmental Niche ◽  
Distribution Models ◽  
Soil Microbiota ◽  
Soil Microbial ◽  
Critical Issues ◽  
Multiple Species ◽  
Species Specific

ABSTRACT Creating accurate habitat suitability and distribution models (HSDMs) for soil microbiota is far more challenging than for aboveground organism groups. In this perspective paper, we propose a conceptual framework that addresses several of the critical issues holding back further applications. Most importantly, we tackle the mismatch between the broadscale, long-term averages of environmental variables traditionally used, and the environment as experienced by soil microbiota themselves. We suggest using nested sampling designs across environmental gradients and objectively integrating spatially hierarchic heterogeneity as covariates in HSDMs. Second, to incorporate the crucial role of taxa co-occurrence as driver of soil microbial distributions, we promote the use of joint species distribution models, a class of models that jointly analyze multiple species’ distributions, quantifying both species-specific environmental responses (i.e. the environmental niche) and covariance among species (i.e. biotic interactions). Our approach allows incorporating the environmental niche and its associated distribution across multiple spatial scales. The proposed framework facilitates the inclusion of the true relationships between soil organisms and their abiotic and biotic environments in distribution models, which is crucial to improve predictions of soil microbial redistributions as a result of global change.

scholarly journals Antagonistic effects of intraspecific cooperation and interspecific competition on thermal performance

eLife ◽  
2020 ◽  
Vol 9 ◽  
Author(s):  
Hsiang-Yu Tsai ◽  
Dustin R Rubenstein ◽  
Bo-Fei Chen ◽  
Mark Liu ◽  
Shih-Fan Chan ◽  
...  
Keyword(s):  
Thermal Performance ◽  
Abiotic Factors ◽  
Biotic Interactions ◽  
Niche Width ◽  
Burying Beetle ◽  
Thermal Niche ◽  
Thermal Performance Curve ◽  
Performance Curves ◽  
Species Specific ◽  
The Relationship

Understanding how climate-mediated biotic interactions shape thermal niche width is critical in an era of global change. Yet, most previous work on thermal niches has ignored detailed mechanistic information about the relationship between temperature and organismal performance, which can be described by a thermal performance curve. Here, we develop a model that predicts the width of thermal performance curves will be narrower in the presence of interspecific competitors, causing a species’ optimal breeding temperature to diverge from that of its competitor. We test this prediction in the Asian burying beetle Nicrophorus nepalensis, confirming that the divergence in actual and optimal breeding temperatures is the result of competition with their primary competitor, blowflies. However, we further show that intraspecific cooperation enables beetles to outcompete blowflies by recovering their optimal breeding temperature. Ultimately, linking abiotic factors and biotic interactions on niche width will be critical for understanding species-specific responses to climate change.

scholarly journals Natural selection on traits and trait plasticity in Arabidopsis thaliana varies across competitive environments

2020 ◽  
Vol 10 (1) ◽  
Author(s):  
Kattia Palacio-Lopez ◽  
Christian M. King ◽  
Jonathan Bloomberg ◽  
Stephen M. Hovick
Keyword(s):  
Arabidopsis Thaliana ◽  
Interspecific Competition ◽  
Flowering Phenology ◽  
Competitive Environment ◽  
Phenotypic Integration ◽  
Competitive Environments ◽  
Selection Processes ◽  
Delayed Flowering ◽  
Plastic Responses ◽  
Trait Correlation

AbstractInterspecific competition reduces resource availability and can affect evolution. We quantified multivariate selection in the presence and absence of strong interspecific competition using a greenhouse experiment with 35 natural accessions of Arabidopsis thaliana. We assessed selection on nine traits representing plant phenology, growth, and architecture, as well as their plasticities. Competition reduced biomass and fitness by over 98%, and plastic responses to competition varied by genotype (significant G × E) for all traits except specific leaf area (SLA). Competitive treatments altered selection on flowering phenology and plant architecture, with significant selection on all phenology traits and most architecture traits under competition-present conditions but little indication that selection occurred in the absence of competitors. Plasticity affected fitness only in competition-present conditions, where plasticity in flowering time and early internode lengths was adaptive. The competitive environment caused changes in the trait correlation structure and surprisingly reduced phenotypic integration, which helped explain some of the observed selection patterns. Despite this overall shift in the trait correlation matrix, genotypes with delayed flowering had lower SLA (thicker, tougher leaves) regardless of the competitive environment, a pattern we have not seen previously reported in the literature. Overall, our study highlights multiple ways in which interspecific competition can alter selective regimes, contributing to our understanding of variability in selection processes over space and time.

scholarly journals Drought responses and their effects on radial stem growth of two co-occurring conifer species in the Mediterranean mountain range

2020 ◽  
Vol 77 (4) ◽  
Author(s):  
Aylin Güney ◽  
Roman Zweifel ◽  
Semra Türkan ◽  
Reiner Zimmermann ◽  
Magnus Wachendorf ◽  
...  
Keyword(s):  
Water Deficit ◽  
Growth Rates ◽  
Water Shortage ◽  
Stem Growth ◽  
Growth Strategy ◽  
Mountain Range ◽  
Summer Drought ◽  
Cedrus Libani ◽  
Juniperus Excelsa ◽  
Species Specific

Abstract Key message Patterns of stem radial variations showed thatCedrus libaniA. Rich. was less limited by summer drought than co-occurringJuniperus excelsaM. Bieb.Cedrus libanirecovered faster from tree water deficit and showed significantly higher radial growth rates and annual stem increments thanJ. excelsa. However, the ability ofJ. excelsato grow more hours per year may indicate a potential benefit in more extreme conditions. Context Knowledge about species-specific drought responses is needed to manage productive forests in drought prone areas. Under water shortage, trees commonly show stem shrinkage, which is assumed to inhibit growth. Aims We investigated whether the two co-existing conifers Juniperus excelsa M. Bieb. and Cedrus libani A. Rich. (growing at the Taurus Mountains, SW-Turkey) show differences in water relations and stem growth in order to evaluate their respective drought tolerance. Methods Stem radius changes were hourly monitored over 2 years using high-resolution point dendrometers. Radial stem growth, tree water deficit-induced stem shrinkage, and maximum daily shrinkage were extracted from stem radius change measurements, investigated for their patterns, and related to environmental conditions. Results Cedrus libani recovered from tree water deficit under higher temperature and vapor pressure deficit than J. excelsa. The number of hours during which stem growth occurred was higher for J. excelsa; however, growth rates and annual increments were significantly lower than in C. libani. Both species showed highest maximum daily shrinkage during the driest months indicating the ability to maintain gas exchange all year round. Conclusion Juniperus excelsa showed a more conservative growth strategy while C. libani was less limited by summer drought and showed more annual stem increment under the conditions investigated.

scholarly journals Diatoms Are Selective Segregators in Global Ocean Planktonic Communities

mSystems ◽  
2020 ◽  
Vol 5 (1) ◽  
Author(s):  
Flora Vincent ◽  
Chris Bowler
Keyword(s):  
Open Access ◽  
Large Scale ◽  
Abiotic Factors ◽  
Biotic Interactions ◽  
Distribution Patterns ◽  
Global Scale ◽  
Global Ocean ◽  
Extensive Literature ◽  
Microbial Association ◽  
Species Specific

ABSTRACT Diatoms are a major component of phytoplankton, believed to be responsible for around 20% of the annual primary production on Earth. As abundant and ubiquitous organisms, they are known to establish biotic interactions with many other members of plankton. Through analyses of cooccurrence networks derived from the Tara Oceans expedition that take into account both biotic and abiotic factors in shaping the spatial distributions of species, we show that only 13% of diatom pairwise associations are driven by environmental conditions; the vast majority are independent of abiotic factors. In contrast to most other plankton groups, on a global scale, diatoms display a much higher proportion of negative correlations with other organisms, particularly toward potential predators and parasites, suggesting that their biogeography is constrained by top-down pressure. Genus-level analyses indicate that abundant diatoms are not necessarily the most connected and that species-specific abundance distribution patterns lead to negative associations with other organisms. In order to move forward in the biological interpretation of cooccurrence networks, an open-access extensive literature survey of diatom biotic interactions was compiled, of which 18.5% were recovered in the computed network. This result reveals the extent of what likely remains to be discovered in the field of planktonic biotic interactions, even for one of the best-known organismal groups. IMPORTANCE Diatoms are key phytoplankton in the modern ocean that are involved in numerous biotic interactions, ranging from symbiosis to predation and viral infection, which have considerable effects on global biogeochemical cycles. However, despite recent large-scale studies of plankton, we are still lacking a comprehensive picture of the diversity of diatom biotic interactions in the marine microbial community. Through the ecological interpretation of both inferred microbial association networks and available knowledge on diatom interactions compiled in an open-access database, we propose an ecosystems approach for exploring diatom interactions in the ocean.

The effect of non-native plant invasions on the dispersal of native seeds.

2020 ◽  
pp. 256-269
Author(s):  
Ruben H. Heleno
Keyword(s):  
Seed Dispersal ◽  
Indirect Effects ◽  
Biotic Interactions ◽  
Plant Invasions ◽  
Native Communities ◽  
Native Seed ◽  
Emergent Structure ◽  
Underlying Mechanisms ◽  
Species Specific

Abstract Non-native plants change the communities they integrate in multiple ways, including direct and indirect effects on co-occurring native vegetation. While direct effects are more obvious, indirect effects, i.e. those mediated by biotic interactions with other trophic levels, can also have pervasive consequences for long-term community persistence. Seed dispersal is a critical stage during the life cycle of most plants, as it lays the foundations for plant recruitment patterns and long-term vegetation dynamics. By interacting with seed-dispersing animals, primarily frugivorous birds and mammals, plants can positively or negatively affect the dispersal of co-occurring native seeds. In an increasingly invaded world, it is thus critically important to identify general trends on the direction and magnitude of these effects. This chapter reviews the empirical evidence supporting such changes and the potential underlying mechanisms driving them. While the direct impacts of plant invasions are relatively easy to document, indirect effects are much harder to detect. Nevertheless, the most important consequence of the incorporation of new fruiting plants into native communities seems to be a direct competition for the services provided by the local dispersers, negatively affecting native seed dispersal rates. However, another key message emerging from the literature is that responses are highly idiosyncratic, and usually habitat- and species-specific, and therefore resistant to broad generalizations. Fruiting phenology, and in particular the synchrony/asynchrony between the availability of native and non-native fruits, seems to be a particularly important driver of the direction of the responses (i.e. towards facilitation or competition). However, most evidence is still derived from anecdotal observations and formal community level assessments are largely missing. Similarly, how invasive plants change the emergent structure of seed dispersal networks remains uncertain, with early evidence suggesting that novel seed dispersal networks might be structurally very similar to native ones. Bringing together classic experimental designs and new technical and analytical tools to provide broad synthesis will be vital in the near future to clarify the direction, magnitude and generality of these effects.

Spatiotemporal dynamics of intermittent stream fish metacommunities in response to prolonged drought and reconnectivity

2016 ◽  
Vol 67 (11) ◽  
pp. 1667 ◽  
Author(s):  
Lucas J. Driver ◽  
David J. Hoeinghaus
Keyword(s):  
Temporal Stability ◽  
Summer Drought ◽  
Intermittent Streams ◽  
Mechanisms Of Resistance ◽  
Intermittent Stream ◽  
North Texas ◽  
Spatial And Temporal Scales ◽  
Habitat Alterations ◽  
Structure And Dynamics ◽  
Species Specific

Hydrological regimes are primary drivers of community structure and dynamics in streams with strong seasonal or annual flood and drought cycles. In the current study, we investigated the dynamics of fish metacommunities in two intermittent streams (Hickory Creek and Clear Creek) in north Texas, USA, by examining changes in diversity, abundance, assemblage structure and temporal stability associated with prolonged seasonal drought and reconnectivity. Diversity (α and γ), abundance and stability increased with initial isolation during summer drought but dramatically declined as drought or drying persisted through the winter (November–December). During post-drought reconnectivity in Hickory Creek, diversity and abundance increased and approached pre-drought levels. Abundance and body size varied greatly among species and indicated species-specific responses (i.e. mortality, recruitment, dispersal) to hydrologic fragmentation and connectivity. Ultimately, assemblage structures were significantly altered by drought in Hickory and Clear creeks, and despite a trend towards recovery in Hickory Creek, assemblages did not fully recover during the present study. Intermittent-stream fishes may be generally adapted to natural drought dynamics; however, climate change and human-mediated habitat alterations may result in prolonged and intensified drought conditions that exceed many species mechanisms of resistance or resilience having potentially large impacts on biodiversity across spatial and temporal scales.

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