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Ongoing climate change poses an increasing threat to biodiversity. To avoid decline or extinction, species need to either adjust or adapt to new environmental conditions or track their climatic niches across space. In sessile organisms such as plants, phenotypic plasticity can help maintain fitness in variable and even novel environmental conditions and is therefore likely to play an important role in allowing them to survive climate change, particularly in the short term. Understanding a species' response to rising temperature is crucial for planning well‐targeted and cost‐effective conservation measures. We sampled seeds of three Hypericum species (H. maculatum, H. montanum, and H. perforatum), from a total of 23 populations originating from different parts of their native distribution areas in Europe. We grew them under four different temperature regimes in a greenhouse to simulate current and predicted future climatic conditions in the distribution areas. We measured flowering start, flower count, and subsequent seed weight, allowing us to study variations in the thermal plasticity of flowering phenology and its relation to fitness. Our results show that individuals flowered earlier with increasing temperature, while the degree of phenological plasticity varied among species. More specifically, the plasticity of H. maculatum varied depending on population origin, with individuals from the leading range edge being less plastic. Importantly, we show a positive relationship between higher plasticity and increased flower production, indicating adaptive phenological plasticity. The observed connection between plasticity and fitness supports the idea that plasticity may be adaptive. This study underlines the need for information on plasticity for predicting species' potential to thrive under global change and the need for studies on whether higher phenotypic plasticity is currently being selected as natural populations experience a rapidly changing climate. [ABSTRACT FROM AUTHOR]

Species distribution models ( SDMs) have been criticized for involving assumptions that ignore or categorize many ecologically relevant factors such as dispersal ability and biotic interactions. Another potential source of model error is the assumption that species are ecologically uniform in their climatic tolerances across their range. Typically, SDMs treat a species as a single entity, although populations of many species differ due to local adaptation or other genetic differentiation. Not taking local adaptation into account may lead to incorrect range prediction and therefore misplaced conservation efforts. A constraint is that we often do not know the degree to which populations are locally adapted. Lacking experimental evidence, we still can evaluate niche differentiation within a species' range to promote better conservation decisions. We explore possible conservation implications of making type I or type II errors in this context. For each of two species, we construct three separate MaxEnt models, one considering the species as a single population and two of disjunct populations. Principal component analyses and response curves indicate different climate characteristics in the current environments of the populations. Model projections into future climates indicate minimal overlap between areas predicted to be climatically suitable by the whole species vs. population-based models. We present a workflow for addressing uncertainty surrounding local adaptation in SDM application and illustrate the value of conducting population-based models to compare with whole-species models. These comparisons might result in more cautious management actions when alternative range outcomes are considered. [ABSTRACT FROM AUTHOR]

According to life-history theory, longer development time may result in bigger adults. However, reaction norms describing age and size at maturity often follow an L-shaped form. This relationship is attributable to the simple notion that slowly growing individuals may not lengthen their development excessively after the maturation decision has been made, for example, when development is time limited in seasonal environments. In arthropods, growth occurs within instars, and thus the optimal growth strategy might be mediated by the phenotypic adjustment of instar numbers. We studied the relationship between age and size at maturity of a lichen-feeding moth, Eilema depressum (Esper) (Lepidoptera: Arctiidae: Lithosiinae), and the variability of instar numbers in relation to achieved adult body mass and time used for maturation. A positive relationship between age and size at maturity was found across developmental pathways and a negative one within the developmental pathways. Directly developing larvae had higher growth rates, attained smaller pupal mass, and passed fewer instars than larvae maturing after overwintering. Host quality did not affect whether larvae matured during the remaining or the next season. High variation in the number of instars together with variable growth rates indicates high plasticity in adaptation to varying environmental conditions. Our results also confirm previous results that instar number variability may be a key characteristic mediating age and size at maturity in insects. [ABSTRACT FROM AUTHOR]

Host use and selection by herbivores are often determined by host chemistry. Lichen secondary chemicals frequently have been assumed to have a defensive role against herbivores similar to that of higher plants, but thus far there is only circumstantial evidence of the adverse effect of lichen secondary chemicals on specialized lichen-feeders. We studied the impact of lichen secondary metabolites on performance and host preference of lichenivorous larvae of the moth Eilema depressum using a recently developed manipulation method that allows the removal of a major part of lichen secondary metabolites from the extracellular space of the lichen thallus without harming their primary metabolism. All larvae died on intact thalli of Vulpicida pinastri and Hypogymnia physodes, whereas, after extraction of most of the lichens' secondary chemicals (e.g., pinastric and physodic acids, respectively), survival of neonate larvae ranged between 75% and 85%. In turn, atranorin, the major secondary metabolite in the cortical layer of Parmelia sulcata, merely retarded the growth of larvae during their first days, but had no long-term impact on survival or performance of larvae. In preference experiments, treated thalli with lowered concentrations of lichen secondary metabolites, with the exception of Xanthoria parietina, were preferred to intact thalli containing secondary chemicals. Our results show that lichen secondary metabolites may act, at natural concentrations, as strong antiherbivore compounds against E. depressum larvae and may play an important role in their host selection. [ABSTRACT FROM AUTHOR]

Journal of Ecology (2004) 92, 505–511 [ABSTRACT FROM AUTHOR]

Summary 1. We compared the larval host preference of four lichenivorous Eilema (Lepidoptera, Arctiidae) species on four common epiphytic lichen species including Hypogymnia physodes , Melanelia exasperata , Vulpicida pinastri and Xanthoria parietina . Survival and growth of larvae on different species were monitored and correlation to qualitative and quantitative variation in lichen secondary compounds was analysed. 2. All moth species preferred M. exasperata , which does not contain polyphenolic substances, over other lichens, but also foraged on other lichens in the food preference experiment. All larvae reared on V. pinastri and H. physodes died during the growth and survival experiment. Survival of larvae on X. parietina and M. exasperata were equal. Larvae grew faster and and bigger on M. exasperata than on other lichens. 3. Consumption and utilization measurements also revealed that M. exasperata was of the highest quality, although the relative consumption rate was highest on X. parietina . Our results indicate that different secondary chemicals have different effect against lichenivores or that larvae are either well adapted to certain chemicals or that these chemicals may have other roles than antiherbivore function for lichens. 4. It is suggested that lichenivorous lepidopteran species may have different adaptations, such as dietary mixing to receive nutrients in optimal proportions or compensatory feeding ability to ensure the maximal growth efficiency on a suboptimal host. [ABSTRACT FROM AUTHOR]

Analyzes the concentration of phenols and key macro-nutrients in Cladina stellaris in dry heath forests in Lapland. Accounts on the physical changes in the lichen microenvironment; Increase of the concentration of perlatolic acid; Confirmation of the chemical structures of the isolate.