Elevational trends in butterfly phenology: implications for species responses to climate change

1. Impacts of global change on the distribution, abundance, and phenology of species have been widely documented. In particular, recent climate change has led to widespread changes in animal and plant seasonality, leading to debate about its potential to cause phenological mismatches among interacting taxa. 2. In mountainous regions, populations of many species show pronounced phenological gradients over short geographic distances, presenting the opportunity to test for effects of climate on phenology, independent of variation in confounding factors such as photoperiod. 3. Here we show for 32 butterfly species sampled for five years over a 1700 m gradient (560–2260 m) in a Mediterranean mountain range that, on average, annual flight period is delayed with elevation by 15–22 days per kilometre. Species mainly occurring at low elevations in the region, and to some extent those flying earlier in the year, showed phenological delays of 23–36 days per kilometre, whereas the flight periods of species that occupy high elevations, or fly in late summer, were consistently more synchronised over the elevation gradient. 4. Elevational patterns in phenology appear to reflect a narrowing phenological window of opportunity for larval and adult butterfly activity of high elevation and late‐flying species. 5. Here, we speculate as to the causes of these patterns, and the consequences for our ability to predict species responses to climate change. Our results raise questions about the use of space–time substitutions in predicting phenological responses to climate change, since traits relating to flight period and environmental associations may influence the capacity of species to adapt to changing climates.     

Rapid Homogenization of Multiple Sources: Genetic Structure of a Recolonizing Population of Fishers

Abstract: Fishers (Martes pennanti) were extirpated from much of southern Ontario, Canada, prior to the 1950s. We hypothesised that the recent recolonization of this area originated from an expansion of the population in Algonquin Provincial Park, which historically served as a refuge for fishers. To test this hypothesis, we created a sampling lattice to encompass Algonquin and the surrounding area, and we collected contemporaneous DNA samples. We sampled fishers from each of 35 sites and genotyped them at 16 microsatellite loci. Using a Bayesian assignment approach, with no a priori geographic information, we inferred 5 discrete genetic populations and used genetic population assignment as a means to cluster sites together. We concluded that the Algonquin Park fisher population has not been a substantial source for recolonization and expansion, which has instead occurred from a number of remnant populations within Ontario, Quebec, and most recently from the Adirondacks in New York, USA. The genetic structure among sampling sites across the entire area revealed a pattern of isolation-by-distance (IBD). However, an examination of the distribution of genetic structure (F_ST/1^- F_ST) at different distances showed higher rates of gene flow than predicted under a strict IBD model at small distances (40 km) within clusters and at larger distances up to 100 km among clusters. This pattern of genetic structure suggests increased migration and gene flow among expanding reproductive fronts.     

Molecular phylogeography reveals an antitropical distribution and local diversification of Solenogyne (Asteraceae) in the Ryukyu Archipelago of Japan and Australia

An antitropical distribution represents an intriguing disjunction, in which a given species or sister lineages occupy regions north and south of the tropics but are absent from the intervening areas. Solenogyne mikadoi endemic to the Ryukyu Archipelago is regarded as an Australian element. Testing the phylogenetic relationship with Australian congeners and discussing the onset timing and causes of the disjunction would potentially enhance the understanding of antitropical distribution. A nuclear ribosomal DNA phylogeny was reconstructed using Bayesian and most parsimonious criteria with allied genera. Solenogyne was monophyletic and clustered with Lagenophora huegelii endemic to Australia, indicating the antitropical distribution and Australian origin of Solenogyne. Multispecies coalescent analysis based on nuclear ribosomal DNA and chloroplast DNA indicated the divergence of S. mikadoi and Australian congeners in the Plio‐Pleistocene. Phylogenetic network analyses suggested that the ancestral lineage of S. mikadoi first colonized the southernmost island in the archipelago and then dispersed northward. The migration to the archipelago likely followed the flourishing of Solenogyne in open vegetation communities that radiated in south‐eastern Australia during the late Pliocene. This disjunction might arise through long‐distance dispersal across the tropics or, alternatively, through extinction in the tropics as a result of unsuitably high temperatures during climate oscillation and/or competitions from diverse tropical flora surviving since the early Tertiary. © 2011 The Linnean Society of London, Biological Journal of the Linnean Society, 2012, 105 , 197–217.     

Effects of carbon dioxide concentration on the interactive effects of temperature and water vapour on stomatal conductance in soybean

Soybeans were grown at three CO₂ concentrations in outdoor growth chambers and at two concentrations in controlled-environment growth chambers to investigate the interactive effects of CO₂, temperature and leaf-to-air vapour pressure difference (LAVPD) on stomatal conductance. The decline in stomatal conductance with CO₂ was a function of both leaf temperature and LAVPD. In the field measurements, stomatal conductance was more sensitive to LAVPD at low CO₂ at 30 °C but not at 35 °C. There was also a direct increase in conductance with temperature, which was greater at the two elevated carbon dioxide concentrations. Environmental growth chamber results showed that the relative stomatal sensitivity to LAVPD decreased with both leaf temperature and CO₂. Measurements in the environmental growth chamber were also performed at the opposing CO₂, and these experiments indicate that the stomatal sensitivity to LAVPD was determined more by growth CO₂ than by measurement CO₂. Two models that describe stomatal responses to LAVPD were compared with the outdoor data to evaluate whether these models described adequately the interactive effects of CO₂, LAVPD and temperature.     

The Effect of Cotyledon Excision on Reproductive Development in Pea (Pisum sativum L.)

The excision of cotyledons from two cultivars of peas soon aftergermination resulted in a lowering of the node of first floweringas well as a delay in both flower initiation and flowering,especially in the late cultivar Greenfeast. This is contraryto the usual view that, when cotyledon excision reduces nodeof first flowering, flower initiation and flowering are hastened,and it seems irreconcilable with the colysanthin theory of Barber(1959). An alternative explanation is proposed.     

Ultrastructural and Cytochemical Studies of 'Air Blisters' in Pilea cadierei Gagnep. and Guillaumin

Cells from the sub-epidermal layer of Pilea cadierei preparedfor electron microscopy using standard fixation and embeddingprocedures appear extremely osmiophilic, with the organellesstanding out in negative relief. However, when tissues werefixed in glutaraldehyde supplemented with either procaine orcaffeine (substances known to complex with phenols) the osmiophilicmaterial was generally limited to the vacuole. After procaineor caffeine fixation the surrounding cytoplasm appeared as inadjacent, nonphenolic cells. Some small aggregates of phenolicmaterial appear in the cisternae of the endoplasmic reticular,indicating these organelles may be involved in either the synthesisor transport of phenolics in Pilea. Since one of the major functionsof phenolics is in light-screening, air blisters may serve toscreen out damaging radiation from the underlying tissue. Thepresence of typical shade-type plastids in Pilea air blistersis a further indication of this light-screening role. Pilea cadierei, aluminium plant, air blister, cytochemistry, ultrastructure, light screening, phenolics