Changes in breeding phenology of eastern Ontario frogs over four decades

Global climate change has been implicated in phenological shifts for a variety of taxa. Amphibian species in particular are sensitive to changes in their environment due to their biphasic life history and restricted reproductive requirements. Previous research has shown that not all temperate amphibian species respond similarly to the same suite of climatic or environmental cues, nor are individual species necessarily uniform in their responses across their range. We examined both the timing of spring emergence and calling phenology of eight anuran species in southeastern Ontario, Canada, using an approximately 40‐year dataset of historical records of amphibian activity. Rana pipiens was the only species out of eight considered to emerge significantly earlier, by an estimated 22 days over four decades. Both R. pipiens and Bufo americanus have advanced initiation of calling over a four‐decade span significantly earlier by an estimated 37.2 and 19.2 days, respectively. Rana sylvatica showed a trend toward earlier emergence by 19 days, whereas we did not detect changes in emergence phenology for the remaining five species. This significant shift in breeding behavior for two species correlates to significant regional increases in spring temperatures of an estimated 2.7–2.8°C overall over four decades. Our study suggests that local temperature increases have affected the timing of emergence and the onset of calling activity in some Ontario anuran species. Global decline or range shifts ultimately may be related to changes in reproductive behavior and timing mediated by shifting climate.     

Herbarium specimens show patterns of fruiting phenology in native and invasive plant species across New England

Premise of the Study

Patterns of fruiting phenology in temperate ecosystems are poorly understood, despite the ecological importance of fruiting for animal nutrition and seed dispersal. Herbarium specimens represent an under‐utilized resource for investigating geographical and climatic factors affecting fruiting times within species, patterns in fruiting times among species, and differences between native and non‐native invasive species.

Methods

We examined over 15,000 herbarium specimens, collected and housed across New England, and found 3159 specimens with ripe fruits, collected from 1849–2013. We examined patterns in fruiting phenology among 37 native and 18 invasive woody plant species common to New England. We compared fruiting dates between native and invasive species, and analyzed how fruiting phenology varies with temperature, space, and time.

Key Results

Spring temperature and year explained a small but significant amount of the variation in fruiting dates. Accounting for the moderate phylogenetic signal in fruiting phenology, invasive species fruited 26 days later on average than native species, with significantly greater standard deviations.

Conclusions

Herbarium specimens can be used to detect patterns in fruiting times among species. However, the amount of intraspecific variation in fruiting times explained by temporal, geographic, and climatic predictors is small, due to a combination of low temporal resolution of fruiting specimens and the protracted nature of fruiting. Later fruiting times in invasive species, combined with delays in autumn bird migrations in New England, may increase the likelihood that migratory birds will consume and disperse invasive seeds in New England later into the year.     

Best environmental predictors of breeding phenology differ with elevation in a common woodland bird species

Temperatures in mountain areas are increasing at a higher rate than the Northern Hemisphere land average, but how fauna may respond, in particular in terms of phenology, remains poorly understood. The aim of this study was to assess how elevation could modify the relationships between climate variability (air temperature and snow melt‐out date), the timing of plant phenology and egg‐laying date of the coal tit (Periparus ater). We collected 9 years (2011–2019) of data on egg‐laying date, spring air temperature, snow melt‐out date, and larch budburst date at two elevations (~1,300 m and ~1,900 m asl) on a slope located in the Mont‐Blanc Massif in the French Alps. We found that at low elevation, larch budburst date had a direct influence on egg‐laying date, while at high‐altitude snow melt‐out date was the limiting factor. At both elevations, air temperature had a similar effect on egg‐laying date, but was a poorer predictor than larch budburst or snowmelt date. Our results shed light on proximate drivers of breeding phenology responses to interannual climate variability in mountain areas and suggest that factors directly influencing species phenology vary at different elevations. Predicting the future responses of species in a climate change context will require testing the transferability of models and accounting for nonstationary relationships between environmental predictors and the timing of phenological events.     

Benthic species of the Kerguelen Plateau show contrasting distribution shifts in response to environmental changes

Marine life of the Southern Ocean has been facing environmental changes and the direct impact of human activities during the past decades. Benthic communities have particularly been affected by such changes although we only slowly understand the effect of environmental changes on species physiology, biogeography, and distribution. Species distribution models (SDM) can help explore species geographic responses to main environmental changes. In this work, we modeled the distribution of four echinoid species with contrasting ecological niches. Models developed for [2005–2012] were projected to different time periods, and the magnitude of distribution range shifts was assessed for recent‐past conditions [1955–1974] and for the future, under scenario RCP 8.5 for [2050–2099]. Our results suggest that species distribution shifts are expected to be more important in a near future compared to the past. The geographic response of species may vary between poleward shift, latitudinal reduction, and local extinction. Species with broad ecological niches and not limited by biogeographic barriers would be the least affected by environmental changes, in contrast to endemic species, restricted to coastal areas, which are predicted to be more sensitive.     

Advancing breeding phenology in response to environmental change in a wild red deer population

Most evidence for advances in phenology of in response to recent climate warming in wild vertebrate populations has come from long‐term studies of birds. Few studies have either documented phenological advances or tested their climatic causes and demographic consequences in wild mammal systems. Using a long‐term study of red deer on the Isle of Rum, Scotland, we present evidence of significant temporal trends in six phenological traits: oestrus date and parturition date in females, and antler cast date, antler clean date, rut start date and rut end date in males. These traits advanced by between 5 and 12 days across a 28‐year study period. Local climate measures associated with plant growth in spring and summer (growing degree days) increased significantly over time and explained a significant amount of variation in all six phenological traits, largely accounting for temporal advances observed in some of the traits. However, there was no evidence for temporal changes in key female reproductive performance traits (offspring birth weight and offspring survival) in this population, despite significant relationships between these traits and female phenology. In males, average antler weights increased over time presumably as a result of improved resource availability and physiological condition through spring and summer. There was no evidence for any temporal change in average male annual breeding success, as might be expected if the timing of male rutting behaviour was failing to track advances in the timing of oestrus in females. Our results provide rare evidence linking phenological advances to climate warming in a wild mammal and highlight the potential complexity of relationships between climate warming, phenology and demography in wild vertebrates.     

Temporal variation in responses of species to four decades of climate warming

Many species are expanding at their leading‐edge range boundaries in response to climate warming. Species are known to respond individualistically to climate change, but there has been little consideration of whether responses are consistent over time. We compared responses of 37 southerly distributed British butterflies over two study periods, first between 1970–1982 and 1995–1999 and then between 1995–1999 and 2005–2009, when mean annual temperature increased regionally by 0.03 °C yr^?1 (a significant rate of increase) and 0.01 °C yr^?1(a nonsignificant increase) respectively. Our study species might be expected to benefit from climate warming. We measured three responses to climate to investigate this; changes in range margin, distribution area and abundance. In general, the responses of species were inconsistent over time. Species that increased their distribution areas during the first period tended to do so again during the second period, but the relationship was weak. Changes in range margins and abundance were not consistent. In addition, only 5/37 species showed qualitatively similar responses in all three response variables over time (three species increased and two species declined in all variables in both periods). Overall rates of range expansion and distribution area change were significantly greater in the second study period, despite the lower rate of warming, perhaps due to species exploiting climate‐distribution lags remaining from the earlier, warmer period. However, there was a significantly greater decline in abundance during the second study period, so range expansions northwards were not necessarily accompanied by increases in distribution area and/or abundance. Hence, species ranges have been thinning as they have expanded northwards. The idiosyncratic responses of these species likely reflect the balance of climatic and habitat drivers of species distribution and abundance changes.     

Androgen-metabolizing enzymes show region-specific changes across the breeding season in the brain of a wild songbird.

The Lapland longspur (Calcarius lapponicus) is an arctic-breeding songbird that shows rapid behavioral changes during a short breeding season. Changes in plasma testosterone (T) in the spring are correlated with singing but not territorial aggression in males. Also, T treatment increases song but not aggression in this species. In contrast, in temperate-zone breeders, song and aggression are highly correlated, and both increase after T treatment. We asked whether regional or temporal differences in androgen-metabolizing enzymes in the longspur brain explain hormone-behavior patterns in this species. We measured the activities of aromatase, 5alpha-reductase and 5beta-reductase in free-living longspur males. Aromatase and 5alpha-reductase convert T into the active steroids 17beta-estradiol (E(2)) and 5alpha-dihydrotestosterone (5alpha-DHT), respectively. 5beta-Reductase deactivates T via conversion to 5beta-DHT, an inactive steroid. We examined seven brain regions at three stages in the breeding season. Overall, aromatase activity was high in the hypothalamus, hippocampus, and ventromedial telencephalon (containing nucleus taeniae, the avian homologue to the amygdala). 5beta-Reductase activity was high throughout the telencephalon. Activities of all three enzymes changed over time in a region-specific manner. In particular, aromatase activity in the rostral hypothalamus was decreased late in the breeding season, which may explain why T treatment at this time does not increase aggression. Changes in 5beta-reductase do not explain the effects of plasma T on aggressive behavior.     

Historical comparisons show evolutionary changes in drought responses in European plant species after two decades of climate change

Plants must continuously respond to environmental changes, and a timely question is whether and how populations respond to ongoing global warming and increased drought frequencies and intensities. Plants can either respond through migration or through phenotypic plasticity or their populations can adapt evolutionarily, which encompasses the evolution of trait means and of trait plasticity. One way to detect such evolutionary changes within plant populations is through historical comparisons where plants grown from seeds collected in the past (“ancestors”) are compared to freshly collected seeds from the same populations (“descendants”) in common garden experiments. We used 21- to 26-year-old seeds stored in seed banks for two multi-species experiments that investigated changes in phenotypic traits and their plasticity conferring drought tolerance in early life stages of European plant species. In the first experiment, we used seedlings of four Mediterranean species, ceased watering and recorded their day of mortality. In the second experiment, we studied phenotypic responses to drought in juvenile plants of nine species originating from temperate regions in Europe. In one of four species in the first experiment, descendants survived significantly longer without watering and were smaller than their ancestors. In the second experiment, descendant plants were generally taller under well-watered conditions but smaller under drought than their ancestors, thus showing stronger plasticity. Our historical comparisons suggest that some populations have likely evolved through changes in trait means and plasticity in ways consistent with adaptation to increased drought. Using seed bank material for historical comparisons has several weaknesses, such as unknown sampling protocols or invisible fractions. However, we show how accurately sampled and stored seed bank collections can be used similar to the resurrection approach for investigating rapid evolutionary processes in early life stages of plants under climate change.     

Comparative toxicity of ten organic chemicals to four earthworm species

Ten organic chemicals were tested for toxicity to four earthworm species: Allolobophora tuberculata, Eisenia fetida, Eudrilus eugeniae and Perionyx excavatus, using the European Economic Community's (EEC) earthworm artificial soil and contact testing procedure. The phenols were the most toxic chemicals tested, followed by the amine, substituted benzenes, halogenated aliphatic hydrocarbon, polycyclic aromatic hydrocarbon and phthalate as the least toxic chemical tested. Correlations among species within each type of test for a given chemical were extremely high, suggesting that the selection of earthworm test species does not markedly affect the assessment of a chemical's toxicity. The correlation between the two tests was low for all test species. The contact test LC50 for a given chemical cannot be directly correlated to an artificial soil test LC50 for the same earthworm species.     

Responses of canopy duration to temperature changes in four temperate tree species: relative contributions of spring and autumn leaf phenology

While changes in spring phenological events due to global warming have been widely documented, changes in autumn phenology, and therefore in growing season length, are less studied and poorly understood. However, it may be helpful to assess the potential lengthening of the growing season under climate warming in order to determine its further impact on forest productivity and C balance. The present study aimed to: (1) characterise the sensitivity of leaf phenological events to temperature, and (2) quantify the relative contributions of leaf unfolding and senescence to the extension of canopy duration with increasing temperature, in four deciduous tree species (Acer pseudoplatanus, Fagus sylvatica, Fraxinus excelsior and Quercus petraea). For 3 consecutive years, we monitored the spring and autumn phenology of 41 populations at elevations ranging from 100 to 1,600 m. Overall, we found significant altitudinal trends in leaf phenology and species-specific differences in temperature sensitivity. With increasing temperature, we recorded an advance in flushing from 1.9 ± 0.3 to 6.6 ± 0.4 days °C⁻¹ (mean ± SD) and a 0 to 5.6 ± 0.6 days °C⁻¹ delay in leaf senescence. Together both changes resulted in a 6.9 ± 1.0 to 13.0 ± 0.7 days °C⁻¹ lengthening of canopy duration depending on species. For three of the four studied species, advances in flushing were the main factor responsible for lengthening canopy duration with increasing temperature, leading to a potentially larger gain in solar radiation than delays in leaf senescence. In contrast, for beech, we found a higher sensitivity to temperature in leaf senescence than in flushing, resulting in an equivalent contribution in solar radiation gain. These results suggest that climate warming will alter the C uptake period and forest productivity by lengthening canopy duration. Moreover, the between-species differences in phenological responses to temperature evidenced here could affect biotic interactions under climate warming.     

Trends in species diversity and composition of urban vegetation over three decades

Question: What was the change in diversity of urban synantropic vegetation in a medium‐sized Central European city during the period of increasing urbanization (1960s‐1990s)? Location: The city of Plzeň, an industrial centre of the western part of the Czech Republic. Methods: Sampling of various types of synanthropic vegetation, conducted in the 1960s, was repeated by using the same methods in the 1990s. This yielded 959 relevés, of which 623 were made in the 1960s and 336 in the 1990s. The relevés were assigned to the following phytosociological classes: Chenopodietea, Artemisietea vulgaris, Galio‐Urticetea, Agropyretea repentis and Plantaginetea majoris. Total number of vascular plant species, evenness index J, number of alien species (classified into archaeophytes and neophytes), and mean Ellenberg indicator values for light, temperature, continentality, moisture, soil reaction, and nutrients were obtained for each relevé. Results: From 1960s to 1990s, there was a significant decrease of species richness and diversity in synanthropic vegetation. The proportion of archaeophytes decreased in most vegetation types, indicating the contribution of this group of species, often confined to specific rural‐like habitats, to the observed impoverishment of ruderal vegetation. The proportion of neophytes did not change between the two periods. Comparison between 1960s and 1990s indicated a decrease in light, temperature, moisture, soil reaction and nutrient indicator values in some vegetation types. In both periods, Artemisieta, Galio‐Urticetea and Chenopodietea formed a distinct group harbouring more species than Agropyretea and Plantaginetea. Neophytes, i.e. recently introduced species, were most represented in the early successional annual vegetation of Chenopodietea, rather than in perennial vegetation of the other classes. Conclusions: Synanthropic vegetation of Plzeň exhibited a general trend of decrease in species diversity.     

四种松毛虫表型性状多样性与环境因子的关系

对马尾松毛虫、落叶松毛虫、云南松毛虫、思茅松毛虫4种松毛虫的8个表型性状(蛹重、蛹长、雌雄虫体重、雌雄虫翅展和雌雄虫体长)进行了遗传多样性分析.结果表明:8项性状指标在4种松毛虫之间差异极显著;在所有性状中变异系数最大的是蛹重(CV=51.99％);对各种群变异系数比较分析发现,变异系数最大的是落叶松毛虫,最小的是云南松毛虫.主成分分析表明,蛹长、雌虫体重和雌虫翅展3个主分量构成的信息量基本能代表这8个性状的变异.系统聚类的结果为马尾松毛虫与落叶松毛虫聚为第一分支,思茅松毛虫和云南松毛虫聚为第二分支.松毛虫属昆虫表型性状的变异与生态环境因子的相关性较密切.     

Long‐term changes in the impacts of global warming on leaf phenology of four temperate tree species

Contrary to the generally advanced spring leaf unfolding under global warming, the effects of the climate warming on autumn leaf senescence are highly variable with advanced, delayed, and unchanged patterns being all reported. Using one million records of leaf phenology from four dominant temperate species in Europe, we investigated the temperature sensitivities of spring leaf unfolding and autumn leaf senescence (S_T, advanced or delayed days per degree Celsius). The S_T of spring phenology in all of the four examined species showed an increase and decrease during 1951–1980 and 1981–2013, respectively. The decrease in the S_T during 1981–2013 appears to be caused by reduced accumulation of chilling units. As with spring phenology, the S_T of leaf senescence of early successional and exotic species started to decline since 1980. In contrast, for late successional species, the S_T of autumn senescence showed an increase for the entire study period from 1951 to 2013. Moreover, the impacts of rising temperature associated with global warming on spring leaf unfolding were stronger than those on autumn leaf senescence. The timing of leaf senescence was positively correlated with the timing of leaf unfolding during 1951–1980. However, as climate warming continued, the differences in the responses between spring and autumn phenology gradually increased, so that the correlation was no more significant during 1981–2013. Our results further suggest that since 2000, due to the decreased temperature sensitivity of leaf unfolding the length of the growing season has not increased any more. These finding needs to be addressed in vegetation models used for assessing the effects of climate change.     

Ontogenetic changes and environmental effects on ocular transmission in four species of coral reef fishes

Filtration by the humors, cornea and lens limits the spectrum of light available for vision as blocking compounds prevent some wavelengths from reaching photo-sensitive cells of the retina. The visual ecology of fishes is dependent upon factors changing with size and/or habitat. We predicted that ontogeny and habitat depth would affect ocular transmission for four fishes, Mulloidichthys flavolineatus, Parupeneus multifasciatus, Acanthurus triostegas, and Naso lituratus. We measured ocular transmission in specimens from a range of sizes (juvenile-adult) and capture depths (<3-37 m), and used the wavelength (nm) where transmission was reduced 50% as our comparative measure (T(50)). We modeled lens transmission varying pigment concentrations and pathlength, and compared predicted versus measured results. P. multifasciatus, M. flavolineatus, and N. lituratus showed a significant increase in short-wavelength blocking with size. A. triostegas were constant across sizes, and showed a slight but significant effect with depth. Comparisons of predicted versus observed transmission values suggest that pigment concentrations are held constant with age for all species, but species- and family-level differences emerge. The accumulation of blocking compounds in ocular tissues is a contributing means for balancing the costs and benefits of admitting short-wavelength radiation to the retina.     

Changes in phenology and abundance of suction-trapped Diptera from a farmland site in the UK over four decades

1. Recently documented insect declines have caused major concerns and an increased interest in studies using long-term population-monitoring data. 2. Samples from a 12.2-m suction trap were used to examine trends in phenology and abundance of Diptera over four decades. 3. The timing of peak flight has advanced by an average of 17 days, from 23 July in 1974 to 6 July in 2014. 4. The abundance of flies has decreased by 37% over the studied period (from April to September), and peak abundance has decreased by 48%. The flight period has started earlier in recent years, and in 2014, the number of flies was higher in spring until the 31st of May than in 1974. Possible causes and impacts of these changes are discussed.     

Long-term changes in breeding phenology at two seabird colonies in the western North Sea

There is compelling evidence that the breeding phenology of many species has changed substantially in recent decades. However, taxonomic and spatial variation in the direction and rate of change is still not well understood. We explored these issues by analysing a dataset containing information on first egg dates of 10 species of seabird at two major breeding colonies (86 km apart) in the western North Sea over a period of 35 years. Within a species, timing of breeding was positively correlated between the two colonies, suggesting that factors affecting the phenology of these species operated at a regional rather than a colony scale. Comparison of time trends among the species revealed contrasting patterns, with some showing no systematic change, others becoming earlier and others later. The clearest species groupings appeared to be among the terns with arrival and/or first egg dates becoming earlier in Arctic Terns Sterna paradisaea , Common Terns Sterna hirundo and Sandwich Terns Sterna sandvicensis , and among the auks (Common Guillemot Uria aalge , Razorbill Alca torda and Atlantic Puffin Fratercula arctica ) and Black-legged Kittiwake Rissa tridactyla where the trend was in the opposite direction towards later breeding. This general trend towards later breeding in the latter group of species contrasts with correlational evidence from many other organisms indicating that breeding phenology is advancing in response to climate change.     

Responses of four arid zone grass species from varying habitats to drought stress

The effects of 4 or 8 drought cycles on four grass species,Cenchrus pennisetiformis, Leptochloa fusca, Panicum turgidum, andPennisetum divisum were assessed in a pot experiment. There were significant differences between the species in biomass production under water stress.C. pennisetiformis andP. turgidum produced significantly greater fresh and dry matter thanP. divisum and especially thanL. fusca. L. fusca had the lowest andP. divisum highest osmotic potentials compared with the other species after the completion of 4 or 8 drought cycles. Osmotic adjustment (difference between osmotic potential of droughted/rehydrated plants and control plants) was highest inL. fusca. The stomatal conductance was significantly decreased with increased drought stress inC. pennisetiformis. The elasticity ofC. pennisetiformis, P. turgidum andP. divisum increased with increase in number of drought cycles, whereas that ofL. fusca remained unchanged.L. fusca andP. turgidum had the lowest leaf hydration of all species after 8 drought cycles. The chlorophyllsa andb in all species remained unaffected by drought treatments. The proline content ofC. pennisetiformis andL. fusca increased significantly with increased drought stress, whereas that ofP. turgidum remained unaffected after 4 or 8 drought cycles.L. fusca synthesized great amount of leaf soluble proteins during 8 drought cycles, whereasP. divisum had low protein content after 4 drought cycles. The protein contents ofC. pennisetiformis andP. turgidum remained unaffected after 8 drought cycles. The leaf epicuticular wax ofL. fusca increased consistently with increased drought stress, but leaf wax ofP. divisum increased only at the highest drought stress and that ofC. pennisetiformis andP. turgidum increased after 4 drought cycles. On the basis of these results it was established thatC. pennisetiformis andP. turgidum were the most tolerant,P. divisum intermediate, andL. fusca the most sensitive to drought stress. The osmotic adjustment did not positively correlate with the degree of drought resistance.     

Locomotor activity rhythm in four wrasse species under varying light conditions

Under controlled laboratory conditions, the locomotor activity rhythms of four species of wrasses (Suezichthys gracilis, Thalassoma cupido, Labroides dimidiatus andCirrhilabrus temminckii) were individually examined using an actograph with infra-red photo-electric switches in a dark room at temperatures of 21.3–24.3°C, for 7 to 14 days. The locomotor activity ofS. gracilis occurred mostly during the light period under a light-dark cycle regimen (LD 12:12; 06:00-18:00 light, 18:00-06:00 dark). The locomotor activity commenced at the beginning of the light period and continued until a little before the beginning of dark period. The diel activity rhythm of this species synchronizes with LD. Under constant illumination (LL) this species shows distinct free-running activity rhythms varying in length from 23 hrs. 39 min. to 23 hrs. 47 min. Therefore,S. gracilis appears to have a circadian rhythm under LL. However, in constant darkness (DD), the activity of this species was greatly suppressed. All the fish showed no activity rhythms in DD conditions. After DD, the fish showed the diel activity rhythm with the resumption of LD, but this activity began shortly after the beginning of light period. The fish required several days to synchronize with the activity in the light period. Therefore,S. gracilis appeared to continue the circadian rhythm under DD. InT. cupido, the locomotor activity commenced somewhat earlier than the beginning of the light period and continued until the beginning of the dark period under LD. The diel activity rhythm of this species synchronizes with LD. Under LL, four of the five specimens of this species tested showed free-running activity rhythms for the first 5 days or longer varying in length from 22 hrs. 54 min. to 23 hrs. 39 min. Although the activity of this species was suppressed under DD, two of five fish showed free-running activity rhythms throughout the experimental period. The lengths of such free-running periods were from 23 hrs. 38 min. to 23 hrs. 50 min. under DD. Therefore, it was ascertained thatT. cupido has a circadian rhythm. InL. dimidiatus, the locomotor activity rhythm under LD resembled that observed inT. cupido. The diel activity rhythm of this species synchronizes with LD. Under LL, four of seven of this species showed free-running activity rhythms throughout the experimental period. The lengths of such free-running periods were from 23 hrs. 07 min. to 25 hrs. 48 min. Although the activity of this species was suppressed under DD, three of five fish showed free-running activity rhythms throughout the experimental period. The lengths of such free-running periods were from 23 hrs. 36 min. to 23 hrs. 41 min. under DD. Therefore, it was ascertained thatL. dimidiatus has a circadian rhythm. Almost all locomotor activity of C.temminckii occurred during the light period under LD. The diel activity rhythm of this species coincides with LD. Under LL, two of four of this species showed free-running activity rhythms throughout the experimental period. The lengths of such free-running periods were from 23 hrs. 32 min. to 23 hrs. 45 min. Although the activity of this species was suppressed under DD, one of the four fish showed free-running activity rhythms throughout the experimental period. The length of the free-running period was 23 hrs. 21 min. under DD. Therefore,C. temminckii appeared to have a circadian rhythm. According to field observations,S. gracilis burrows and lies in the sandy bottom whileT. cupido, L. dimidiatus, andC. temminckii hide and rest in spaces among piles of boulders or in crevices of rocks during the night. It seems that the differences in nocturnal behavior among the four species of wrasses mentioned above are closely related to the intensity of endogenous factors in their locomotor activity rhythms.     

The effects of four decades of climate change on the breeding ecology of an avian sentinel species across a 1,500‐km latitudinal gradient are stronger at high latitudes

Global warming affects breeding phenology of birds differentially with latitude, but there is contrasting evidence about how the changing climate influences the breeding of migrating songbirds at their northern breeding range. We investigate the effect of climate warming on breeding time and breeding success of European pied flycatchers Ficedula hypoleuca in Sweden during a period of 36 years using nest reports from bird ringing. To account for the latitudinal variation, we divided Sweden into three latitudinal bands (northern, intermediate, and southern). We applied a sliding window approach to find the most influential period and environment characteristics (temperature, vegetation greenness, and precipitation), using linear mixed models and model averaging. Our results show a long‐term advancement of breeding time related to increasing spring temperature and vegetation greenness during a period before hatching. Northern breeders revealed a larger advancement over the years (8.3 days) compared with southern breeders (3.6 days). We observed a relatively stronger effect of temperature and greenness on breeding time in the north. Furthermore, northern birds showed an increase in breeding success over time, while birds breeding at southern and intermediate latitudes showed reduced breeding success in years with higher prehatching temperatures. Our findings with stronger environment effects on breeding time advancement in the north suggest that pied flycatchers are more responsive to weather cues at higher latitudes. Breeding time adjustment and, potentially, low competition help explain the higher long‐term success observed in the north. Reduced breeding success at more southerly latitudes suggests an inability to match breeding time to very early and warm springs, a fate that with continued climate change could also be expected for pied flycatchers and other long‐distance migrants at their very northern breeding range.