Rapid Shifts of Peak Flowering Phenology in 12 Species under the Effects of Extreme Climate Events in Macao.
ABSTRACT: Plant phenology is sensitive to climate change; the timing of flowering has served as a visible indicator of plant phenology in numerous studies. The present study used phenological records from a manual monitoring program to characterize the flowering phenology of 12 species in Guia Hill, Macao. The mean peak flowering dates (PFDs) of these species ranged from March to September, 41.7% of which occurred in May. The earliest or latest PFDs of nine species occurred in 2013, a year with extremely heavy rain events in early spring. In addition, we found that, in the 5-year period, the monthly mean temperature or monthly precipitation in two periods, specifically 1) during November to December of the previous year and 2) during 0-2 months before the PFDs of each species, were significantly correlated with the PFD of eight species. The result showed that, even though complex species-specific responses to the characteristics of climate widely exist, most species in the present study responded to shifts in climate shifts in these two periods. In addition, some species were extraordinarily sensitive to extreme climate events. Precipitation was more effective in altering flowering date than temperature, especially among the late-flowering species in Guia Hill, Macao.
Project description:Premise of the Study:Herbarium specimens are increasingly used as records of plant flowering phenology. However, most herbarium-based studies on plant phenology focus on taxa from temperate regions. Here, we explore flowering phenologic responses to climate in the subtropical plant genus Protea (Proteaceae), an iconic group of plants that flower year-round and are endemic to subtropical Africa. Methods:We present a novel, circular sliding window approach to investigate phenological patterns developed for species with year-round flowering. We employ our method to evaluate the extent to which site-to-site and year-to-year variation in temperature and precipitation affect flowering dates using a database of 1727 herbarium records of 25 Protea species. We also explore phylogenetic conservatism in flowering phenology. Results:We show that herbarium data combined with our sliding window approach successfully captured independently reported flowering phenology patterns (r = 0.93). Both warmer sites and warmer years were associated with earlier flowering of 3-5 days/°C, whereas precipitation variation had no significant effect on flowering phenology. Although species vary widely in phenological responsiveness, responses are phylogenetically conserved, with closely related species tending to shift flowering similarly with increasing temperature. Discussion:Our results point to climate-responsive phenology for this important plant genus and indicate that the subtropical, aseasonally flowering genus Protea has temperature-driven flowering responses that are remarkably similar to those of better-studied northern temperate plant species, suggesting a generality across biomes that has not been described elsewhere.
Project description:Climate change has resulted in major changes in plant phenology across the globe that includes leaf-out date and flowering time. The ability of species to respond to climate change, in part, depends on their response to climate as a phenological cue in general. Species that are not phenologically responsive may suffer in the face of continued climate change. Comparative studies of phenology have found phylogeny to be a reliable predictor of mean leaf-out date and flowering time at both the local and global scales. This is less true for flowering time response (i.e., the correlation between phenological timing and climate factors), while no study to date has explored whether the response of leaf-out date to climate factors exhibits phylogenetic signal. We used a 52-year observational phenological dataset for 52 woody species from the Forest Botanical Garden of Heilongjiang Province, China, to test phylogenetic signal in leaf-out date and flowering time, as well as, the response of these two phenological traits to both temperature and winter precipitation. Leaf-out date and flowering time were significantly responsive to temperature for most species, advancing, on average, 3.11 and 2.87 day/°C, respectively. Both leaf-out and flowering, and their responses to temperature exhibited significant phylogenetic signals. The response of leaf-out date to precipitation exhibited no phylogenetic signal, while flowering time response to precipitation did. Native species tended to have a weaker flowering response to temperature than non-native species. Earlier leaf-out species tended to have a greater response to winter precipitation. This study is the first to assess phylogenetic signal of leaf-out response to climate change, which suggests, that climate change has the potential to shape the plant communities, not only through flowering sensitivity, but also through leaf-out sensitivity.
Project description:Vernal herbs are exposed to the risk of climate change under spring frost and canopy closure. Although vernal herbs contribute to the biodiversity of the understorey layer in temperate forests, few studies assessed the effect of climate change on the phenology of the herbs. To examine phenological shifts in flowering seasons of vernal herb species caused by climate change, a greenhouse experiment was conducted using four species (Adonis amurensis, Hepatica nobilis var. japonica, Viola phalacrocarpa, and Pulsatilla cernua) under two temperature conditions (ambient or elevated temperature) and two precipitation conditions (convective or reduced precipitation). Experimental warming advanced overall aspects of the flowering timing including the first and last day of flowering. The growth of flowering stalk was also promoted by elevated temperature. Effects of decreased precipitation varied among species, which advanced the last day of the flowering of the later flowering species. Consequently, a decrease in overall flowering period length was observed. These results indicate that overall, climate change results in a shortening of the flowering season of vernal herb species, specifically at a higher temperature and under conditions of less precipitation.
Project description:Bromus tectorum (cheatgrass) has successfully invaded and established throughout the western United States. Bromus tectorum grows early in the season and this early growth allows B. tectorum to outcompete native species, which has led to dramatic shifts in ecosystem function and plant community composition after B. tectorum invades. If the phenology of native species is unable to track changing climate as effectively as B. tectorum's phenology then climate change may facilitate further invasion. To better understand how B. tectorum phenology will respond to future climate, we tracked the timing of B. tectorum germination, flowering, and senescence over a decade in three in situ climate manipulation experiments with treatments that increased temperatures (2°C and 4°C above ambient), altered precipitation regimes, or applied a combination of each. Linear mixed-effects models were used to analyze treatment effects on the timing of germination, flowering, senescence, and on the length of the vegetative growing season (time from germination to flowering) in each experiment. Altered precipitation treatments were only applied in early years of the study and neither precipitation treatments nor the treatments' legacies significantly affected B. tectorum phenology. The timing of germination did not significantly vary between any warming treatments and their respective ambient plots. However, plots that were warmed had advances in the timing of B. tectorum flowering and senescence, as well as shorter vegetative growing seasons. The phenological advances caused by warming increased with increasing degrees of experimental warming. The greatest differences between warmed and ambient plots were seen in the length of the vegetative growing season, which was shortened by approximately 12 and 7 days in the +4°C and +2°C warming levels, respectively. The effects of experimental warming were small compared to the effects of interannual climate variation, suggesting that interactive controls and the timing of multiple climatic factors are important in determining B. tectorum phenology. Taken together, these results help elucidate how B. tectorum phenology may respond to future climate, increasing our predictive capacity for estimating when to time B. tectorum control efforts and how to more effectively manage this exotic annual grass.
Project description:Climate change is shifting both the habitat suitability and the timing of critical biological events, such as flowering and fruiting, for plant species across the globe. Here, we ask how both the distribution and phenology of three food-producing shrubs native to northwestern North America might shift as the climate changes. To address this question, we compared gridded climate data with species location data to identify climate variables that best predicted the current bioclimatic niches of beaked hazelnut (Corylus cornuta), Oregon grape (Mahonia aquifolium), and salal (Gaultheria shallon). We also developed thermal-sum models for the timing of flowering and fruit ripening for these species. We then used multi-model ensemble future climate projections to estimate how species range and phenology may change under future conditions. Modelling efforts showed extreme minimum temperature, climate moisture deficit, and mean summer precipitation were predictive of climatic suitability across all three species. Future bioclimatic niche models project substantial reductions in habitat suitability across the lower elevation and southern portions of the species' current ranges by the end of the 21st century. Thermal-sum phenology models for these species indicate that flowering and the ripening of fruits and nuts will advance an average of 25 days by the mid-21st century, and 36 days by the late-21st century under a high emissions scenario (RCP 8.5). Future changes in the climatic niche and phenology of these important food-producing species may alter trophic relationships, with cascading impacts on regional ecosystems.
Project description:Because the flowering and fruiting phenology of plants is sensitive to environmental cues such as temperature and moisture, climate change is likely to alter community-level patterns of reproductive phenology. Here we report a previously unreported phenomenon: experimental warming advanced flowering and fruiting phenology for species that began to flower before the peak of summer heat but delayed reproduction in species that started flowering after the peak temperature in a tallgrass prairie in North America. The warming-induced divergence of flowering and fruiting toward the two ends of the growing season resulted in a gap in the staggered progression of flowering and fruiting in the community during the middle of the season. A double precipitation treatment did not significantly affect flowering and fruiting phenology. Variation among species in the direction and magnitude of their response to warming caused compression and expansion of the reproductive periods of different species, changed the amount of overlap between the reproductive phases, and created possibilities for an altered selective environment to reshape communities in a future warmed world.
Project description:The pace of climate change in the Arctic is dramatic, with temperatures rising at a rate double the global average. The timing of flowering and fruiting (phenology) is often temperature dependent and tends to advance as the climate warms. Herbarium specimens, photographs, and field observations can provide historical phenology records and have been used, on a localised scale, to predict species' phenological sensitivity to climate change. Conducting similar localised studies in the Canadian Arctic, however, poses a challenge where the collection of herbarium specimens, photographs, and field observations have been temporally and spatially sporadic. We used flowering and seed dispersal times of 23 Arctic species from herbarium specimens, photographs, and field observations collected from across the 2.1 million km<sup>2</sup> area of Nunavut, Canada, to determine (1) which monthly temperatures influence flowering and seed dispersal times; (2) species' phenological sensitivity to temperature; and (3) whether flowering or seed dispersal times have advanced over the past 120 years. We tested this at different spatial scales and compared the sensitivity in different regions of Nunavut. Broadly speaking, this research serves as a proof of concept to assess whether phenology-climate change studies using historic data can be conducted at large spatial scales. Flowering times and seed dispersal time were most strongly correlated with June and July temperatures, respectively. Seed dispersal times have advanced at double the rate of flowering times over the past 120 years, reflecting greater late-summer temperature rises in Nunavut. There is great diversity in the flowering time sensitivity to temperature of Arctic plant species, suggesting climate change implications for Arctic ecological communities, including altered community composition, competition, and pollinator interactions. Intraspecific temperature sensitivity and warming trends varied markedly across Nunavut and could result in greater changes in some parts of Nunavut than in others.
Project description:Increases in nitrogen (N) deposition and variation in precipitation have been occurring in temperate deserts; however, little information is available regarding plant phenological responses to environmental cues and their relationships with plant growth pattern in desert ecosystems. In this study, plant phenology and growth of six annuals in response to N and water addition were monitored throughout two consecutive growing seasons in 2011 and 2012 in a temperate desert in northwestern China. The effects of N and water addition on reproductive phenology differed among plant species. N and water addition consistently advanced the flowering onset time and fruiting time of four spring ephemerals; however, their effects on two spring-summer annuals were inconsistent, with advances being noted in one species and delays in another. N and water addition alone increased plant height, relative growth rate, leaf number, flower number, and individual biomass, while their combinative effects on plant growth and reproductive phenology were dependent on species. Multiple regression analysis showed that flowering onset time was negatively correlated with relative growth rate of two species, and negatively correlated with maximum plant height of the other four species. Our study demonstrates that phenological responses to increasing precipitation and N deposition varied in annuals with different life histories, whereby the effects of climate change on plant growth rate were related to reproductive phenology. Desert annuals that were able to accelerate growth rate under increasing soil resource availability tended to advance their flowering onset time to escape drought later in the growing season. This study promotes our understanding of the responses of temperate desert annuals to increasing precipitation and N deposition in this desert.
Project description:Species flower production and flowering phenology vary from year to year due to extrinsic factors. Inter-annual variability in flowering patterns may have important consequences for attractiveness to pollinators, and ultimately, plant reproductive output. To understand the consequences of flowering pattern variability, a community approach is necessary because pollinator flower choice is highly dependent on flower context. Our objectives were: 1) To quantify yearly variability in flower density and phenology; 2) To evaluate whether changes in flowering patterns result in significant changes in pollen/nectar composition. We monitored weekly flowering patterns in a Mediterranean scrubland community (23 species) over 8 years. Floral resource availability was estimated based on field measures of pollen and nectar production per flower. We analysed inter-annual variation in flowering phenology (duration and date of peak bloom) and flower production, and inter-annual and monthly variability in flower, pollen and nectar species composition. We also investigated potential phylogenetic effects on inter-annual variability of flowering patterns. We found dramatic variation in yearly flower production both at the species and community levels. There was also substantial variation in flowering phenology. Importantly, yearly fluctuations were far from synchronous across species, and resulted in significant changes in floral resources availability and composition at the community level. Changes were especially pronounced late in the season, at a time when flowers are scarce and pollinator visitation rates are particularly high. We discuss the consequences of our findings for pollinator visitation and plant reproductive success in the current scenario of climate change.
Project description:BACKGROUNDS AND AIMS:Tropical plant species are already suffering the effects of climate change and projections warn of even greater changes in the following decades. Of particular concern are alterations in flowering phenology, given that it is considered a fitness trait, part of plant species ecological niche, with potential cascade effects in plant-pollinator interactions. The aim of the study was to assess the potential impacts of climate change on the geographical distribution and flowering phenology of hummingbird-pollinated plants. METHODS:We implemented ecological niche modelling (ENM) to investigate the potential impacts of different climate change scenarios on the geographical distribution and flowering phenology of 62 hummingbird-pollinated plant species in the Brazilian Atlantic Forest. KEY RESULTS:Distribution models indicate future changes in the climatic suitability of their current habitats, suggesting a tendency towards discontinuity, reduction and spatial displacement. Flowering models indicate that climate can influence species phenology in different ways: some species may experience increased flowering suitability whereas others may suffer decreased suitability. CONCLUSIONS:Our results suggest that hummingbird-pollinated species are prone to changes in their geographical distribution and flowering under different climate scenarios. Such variation may impact the community structure of ecological networks and reproductive success of tropical plants in the near future.