Phenological Aspects Research Articles

Host-driven phenotypic and phenological differentiation in sympatric races of a parasitic plant

Host specificity is a key factor influencing the ecology and evolutionary diversification of parasitic organisms. Host specialisation and geographic isolation are known to lead to the genetic differentiation of allopatric races in parasitic plants. However, how divergence can co-occur in sympatry remains largely unknown. We investigated phenological and phenotypic differentiation and potential reproductive isolation among three sympatric genetic races of Cytinus hypocistis (Cytinaceae) - an extreme endophytic holoparasite with a high degree of host specialisation. We compared spatio-temporal variations in flowering phenology, flower production, floral longevity, floral rewards, and morphology, and conducted inter-race pollinations among three races parasitising Cistus ladanifer, C. salviifolius, and Halimium halimifolium (Cistaceae) in six co-occurring populations. We found that host-defined genetic races differed significantly across multiple phenotypic and phenological aspects – a phenomenon previously overlooked due to the plants’ cryptic morphology. The race parasitising H. halimifolium showed earlier blooming, higher floral display, longer flowers, and higher pollen production and nectar concentration; the race on C. salviifolius showed later flowering, significantly lower floral display and smaller flowers with lower floral rewards; the race on C. ladanifer had intermediate characteristics. Genetic races were interfertile yet may remain differentiated by restricted gene flow and host-driven selection pressures. Together, our data point to a rare case of sympatric divergent evolution hiding in plain sight: apparently morphologically similar co-occurring parasite races can be genetically, phenotypically, and phenologically distinct. This hitherto unreported example of host-driven sympatric diversification challenges how species concepts are applied to cryptic parasitic plant races.

Carbon Flux Models in a Zonally Dry Tropical Forest Area (Caatinga)

Studies on energy exchange in ecosystems are critical for understanding carbon flows amid different vegetation patterns. In semi-arid areas, comprehending the variability in carbon absorption is essential for quantifying and anticipating the impacts of changes in the caatinga ecosystem. This study aims to calibrate and evaluate models for Gross Primary Production (GPP), Net Ecosystem Exchange (NEE), and Ecosystem Respiration (Reco) in the caatinga biome. NEE measurements were obtained and calculated at 30-minute intervals using EddyPro 3.6 software, from raw data measured at 10 Hz. GPP was estimated by partitioning NEE and Reco, all measured in micromoles of CO2 per square meter per second (μmol CO2m⁻²s⁻¹) using the eddy covariance (EC) tower, installed in a legal reserve at Embrapa Semiárido, in Petrolina, Pernambuco, within a section of the caatinga canopy. Following the measurement of carbon fluxes and ecosystem respiration, field measurements were conducted using a portableFieldSpec HandHeld spectroradiometer to obtain the reflectance of the canopy around the turbulent eddy covariance tower. These measurements were carried out in 2015 in a preserved caatinga area. Multiple linear regression models weredeveloped to estimate carbon fluxes from orbital images, enabling accurate estimation of GPP, NEE, and Reco, using the MODIS/Terra Daily Surface Reflectance product (MOD09GA). The primary results demonstrate the effectiveness of the developed models, particularly the GPP model, which exhibited the best statistical indices (R = 0.97; R² = 0.95; Root Mean Square Error = 0.20). Observations from the EC tower indicated that the models developed to estimate NEE, GPP, and Reco, using visible and near-infrared reflectance data, accurately represented the dry period and effectively captured the phenological aspects of the caatinga ecosystem.

Heading and maturity date prediction using vegetation indices: A case study using bread wheat, barley and oat crops

Contemporary crop research programs involve the evaluation of numerous micro-plots spread across extensive experimental fields. As a result, there is a growing need to depart from labor-intensive manual measurements when assessing phenological data. The growing significance of high throughput phenotyping platforms (HTTP), including unmanned aerial vehicles (UAVs), has rendered these technologies essential in crop research. The overall objective of this study is to explore and validate the use of HTTP methodologies, specifically the potential of vegetation indices (VIs) derived from conventional RGB images, to forecast the date of heading (DH) and maturity (DM) for various cereal crops under different irrigation conditions. To pinpoint DH and DM prediction, a total of nine UAV surveys were conducted throughout the entire crop cycle. Prediction models for DH and DM using VIs were successfully developed for various crop species, explaining 65 % of the variance in bread wheat and 75 % in oats. The highest percentages of variance explained were achieved when models were developed separately for the two irrigation conditions (well-irrigated and rainfed). However, the percentage of variance explained by these models decreased when applied to barley (R²<0.5 for DH). Notably, including final plant height as a predictor increased the percentage of variance explained by the models only for irrigated bread wheat. Furthermore, the utilization of multi-temporal equations, which amalgamated data from diverse UAV surveys, notably enhanced the percentage of variance explained by the model (+160.71 % improvement in DH predictions), particularly those tailored to each specific crop species and irrigation condition. The investigation additionally established a thorough protocol for modeling the phenological aspects of cereal crops utilizing data acquired from UAVs, thereby enhancing the accessibility of this technology for measurements of phenology in large crop research programs.

MORPHOLOGICAL AND PHENOLOGICAL CHARACTERIZATION OF SUNFLOWER SEEDS

In recent years, the sunflower crop has stood out worldwide as the fifth oilseed in raw material production, so it is necessary to know more about this crop. This review aims to describe the importance of sunflower cultivation, its morphological and phenological aspects, seed quality, treatment and sowing. This study took place in 2023. In this review, different works were used as a basis to develop this review, since sunflower cultivation has great importance in the commercial scenario, mainly in the production of vegetable oils and other sunflower-based by-products, but the Information is still scarce about the culture and the demand for production is high among producers in different states and municipalities, which is why it was necessary to look for information that would help resolve some doubts and bring more information about this beautiful crop that is the sunflower, through this review.

Terrestrial orchid diversity in Hosanagara taluk of Shimogga district Central Western Ghats region of KarnatakaTerrestrial orchid diversity in Hosanagara taluk of Shimogga district Central Western Ghats region of Karnataka.

The current article evaluates the study of terrestrial orchids in the Hosanagara taluk of Shimogga district, reports a total of 30 terrestrial orchid species in the Hosanagara taluk region Shimogga district Karnataka from the period of January 2019-January 2022, and provides information on their distribution, phenology aspects, and biological status in the Hosanagara taluk of Shimogga district. Extensive field surveys were carried out periodically in different parts of the taluk, particularly in grasslands and hilly regions, to study the plant's diversity and phenological character. It was noticed that, when compared to other species, the Habenaria species is richly distributed in the Hosanagara taluk region. During field trips, some anthropogenic activities that have a significant impact on the diversity of terrestrial orchids were also observed. To learn more about the variety and current state of terrestrial orchid species in the Hosanagara taluk in the Shimogga District of Karnataka, further research must be conducted.

Seasonality of Violet-winged grasshopper (Tropidacris collaris) (Stoll, 1813) (Orthoptera: Romaleidae) in the dwarf cashew

Tropidacris collaris (Stoll, 1813) is a polyphagous pest, found throughout the South American continent.It has recently been reported to cause damage to cashew trees. The aim of this study was to evaluate the population dynamics of T. collaris in the dwarf cashew, the effects of climate variables on the population dynamics of T. collaris, and the population dynamics of T. collaris in relation to the phenological stages of the dwarf cashew. Violet-winged grasshopper was collected in a clonal garden with 35 dwarf cashew clones (Anacardium occidentale L.) in Pacajus, Ceará, Brasil. The specimens were randomly captured using an entomological net in two collectors spaced 10 m apart. The collections were made between 09:00 and 11:00, in two 45-min shifts separated by an interval of 15 min. In the laboratory, the insects were separated and weighed, and the females dissected to assess the degree of maturation of the ovaries (I, II and III) and classify the ovipositor valves. A greater abundance of adults was found in December 2017 and June 2018. The number of females with mature ovaries (type III) showed a positive correlation with ovipositors with open valves, such ovaries being registered in December 2017, and in January and July 2018. Wind speed, evapotranspiration and relative humidity showed a significant correlation with the nymph population of T. collaris. The greatest peaks in the nymph population were stimulated by the leaf fall/leaf flux phenological stages of the dwarf cashew. In this study we show some of the phenological aspects of T. collaris under field conditions, correlated with climatic and phenological variables of the cashew tree. These results may help in decision-making about the application of methods to control T. collaris in tropical regions, as this insect is polyphagous, and its large size has great potential for damage to several crops

Phenological aspects of the development of sweet cherry varieties in the environmental conditions of the Right-Bank Forest-Steppe of Ukraine

The article presents the results of the study of the seasonal rhythm of the growth and development processes of sweet cherry varieties in the conditions of the Right-Bank Forest Steppe of Ukraine. The beginning of culture development, passage and duration of the main phenophases are determined. There is slight varietal variability between the dates of the beginning and duration of vegetation in accordance with changes in weather conditions. As a result of the conducted observations, it was established that the beginning of vegetation of sweet cherry varieties takes place in the first decade of April. The beginning of flowering of cherry trees is noted in the first half of the third decade of April, the variation of cherry blossoming beginning over the years reaches 5–10 days, which is most typical for the example of the «Dar Mlieva» and «Drogan yellow» varieties. The onset of harvestable ripeness largely determines the variety's belonging to the ripeness group. The fruits of the «Mliivska yellow», «Dar Mlieva», and «Zoryana» varieties are the first to be harvested, and after 26 days, the fruits of the «Amazon» variety are harvested. According to the results of observations, sweet cherry varieties were conditionally divided into groups of ripeness: early ripening, in which the fruits ripen 44-48 days after flowering, medium ripening – fruits ripen 50–60 days after the end of flowering, late ripening – fruits ripen later than 60 days after flowering. Depending on the onset of the harvestable ripeness of the fruits and the duration of the fruiting phase, for timeliness and convenience of harvesting it became possible to create a kind of harvesting conveyor. The duration of the growing season was on average 186 days in the early-ripening group of sweet cherry varieties with the shortest period in the «Mliivska yellow» variety, 191 days for the medium-ripening group varieties with the longest period in the «Melitopolska krapchasta» variety and the shortest in the «Alyonushka» variety, in the lateripening varieties «Biruza» and «Amazon» varieties 196 and 200 days respectively. Key words: sweet cherry varieties, phenological phases, vegetation period, vegetative organs, duration of the growing season.

Improving Neural Network classification of native forest in New Zealand with phenological features

ABSTRACT Changes in Vegetation Indices (VIs) over time can describe vegetation phenology; however, it is not known which phenological features contribute most to land cover classification. Feature selection could potentially solve this problem. In this study, phenological feature importance and selection were evaluated by using two-year Sentinel-2 (S-2) data and single-date PlanetScope (PS) to classify a 50 km2 native podocarp forest in New Zealand. The study area was classified into nine classes. Single-date PS and S-2 data were fused to a base image with the same spatial resolution as PS and 8 bands containing spectral data from S-2; this image was used to produce 30 Vegetation Indices (VIs). Phenological features – amplitude (AMP) and phase (PH) were extracted from these VIs using time-series S-2 only, and harmonic analysis in Google Earth Engine. For accurately classifying forests and identifying the most important features, three classification scenarios (fused bands & VIs, fused bands & phenological features, fused bands & VIs & phenological features) were developed using a Neural Network. Variable Selection Using Random Forest (VSURF) was applied on these scenarios to evaluate the impact of feature selection. Results indicate that VSURF could reduce the time needed for the classification while maintaining a comparable level of accuracy. Phenological features improved accuracy from 90% to 94%, driven mostly by Red-Edge Triangulated Vegetation Index-AMP&PH, Normalised Near-Infrared-PH, Greenness Index-PH, Water Body Index-PH, Normalised Difference Vegetation Index-PH, Normalised Green-PH, Red-Edge Normalised Difference Vegetation Index-PH, Leaf Chlorophyll Content-AMP, and Simple Near-Infrared and Blue Ratio-PH. These features reflect changes in the structure, biochemical, and physiological characteristics of the canopy. A lack of ground-based measurements precluded an evaluation of the accuracy of these phenological aspects and an explanation of their distinctive contribution to the model. Overall, the findings show that specific phenological features can improve the classification of New Zealand’s indigenous podocarp forests.

Phenological variations of avocado cv. Hass and their relationship with thermal time under tropical conditions

In recent years, the avocado has been one of the most dynamic fruits in the world market. In particular, cv. Hass stands out due to its productivity, nutritional quality, and acceptance. Under tropical conditions, weather elements, especially air temperature, and precipitation, affect the productivity and quality of cv. Hass. However, in tropical environments, many relationships between weather and phenological aspects of this cultivar are still unknown. Given this situation, our aim was to identify the variation and degree of association between the phenology of avocado cv. Hass and thermal time (TT) under low-latitude conditions. Eight commercial fields planted with cv. Hass grafted onto Antillean genotypes, located in an altitudinal transect between 1,700 and 2,500 m, were evaluated. The evaluation was carried out for three years and was focused on determining the differences in avocado phenological patterns associated with different environmental variables monitored by weather stations at each location. Air temperature data were used to calculate the base temperature (BT) using different methods for all phenological stages. Later the TT was determined for each stage and all locations. The results show that the duration of each phenological stage varies as a function of elevation (air temperature) and that the phenological stages overlap at the regional, crop field, and plant levels at different periods of the year, generating a high phenological variability but with specific patterns associated with temperature and precipitation. The BT for each phenological stage varied between 0.3 and 7.5 °C, and TT was found to vary depending on the method of calculation. Our work suggests that the generalization of a BT of 10 °C is not applicable for avocado cv. Hass crops under tropical conditions, specifically in the case of Colombia. Detailed studies of phenological relationships with respect to climatic variables will allow a better approximation of the productive behavior of avocado cv. Hass.

Aspects of Tree Species Phenology and Diversity for Conservation in the Chimpanzee Forest Habitat Kwano, Gashaka Gumti National Park, Nigeria

Changes in lifecycle forms of tree species seriously affect their production leading to global warming which has a lot of influence on peoples’ economic status through the provision of ecosystem services. It is important to study the lifecycle changes occurring in tree species and their diversity as a result of global warming since a lot of tree species serves as food to wild animals their absence means animals which depend on them for food will starve to death or migrate thereby affecting conservation activities as well as the wellbeing of people who depends on the park and conservation projects operating within the park for a means of livelihood.&#x0D; An aspect of Tree species Phenology and Diversity for Conservation in Chimpanzee Forest Habitat at Kwano, Gashaka Gumti National Park, Nigeria was conducted with the view to examine the phenology and diversity of tree species in the forest for better conservation strategy. An 8km transect with tagged trees was monitored on foot for phenological activities of leafing, flowering, fruiting and leaf shedding for 3 months. Shannon-Wiener’s Diversity Index (SWDI) was used to determine tree species diversity. ANOVA was used to compare the phenological data among the months of study. SWDI was 4.115. A total of 867 individual tree species consisting of 127 species from 45 families and with 4 unidentified tree species found on this transect indicated that Anogeissus leiocarpus (7.04%) is the highest in the number of the tree species, Trichilia martineani (6.34%) and Crossopteryx febrifuga (5.65%). Euphorbiaceae family (17.42%) was the highest among the diverse tree species observed in Kwano forest followed by Combretaceae (9.80%) and third by Caesalpinoideae (8.65%). Cappar idaceae, Lecythidaceae, Calophyllaceae, Melianthaceae, Celtidaceae, Celastraceae, Ma esaceae, Burseraceae, Rutaceae, and Dracaeroaceae each with 0.12% were the least family es observed. Only 0.12% tree species was observed leafing, 3.92%, 2.19% and 1.73% flowering I n June, July and August respectively while 3.92%, 7.27% and 7.96% were fruiting in June, July and August respectively, none was observed shedding leaves. Comparison of the phenological data reveals significant differences in fruiting and flowering (P &lt; 0.05), none in leafing and leaf shedding (P &gt;0.05). Understanding the phenology and tree species diversity of this forest could enhance better conservation strategies. More phenological studies are recommended in the Park.

Phenological aspects and physiological quality of seeds of Mimosa caesalpiniifolia Benth.

Producing forest species in regions with limiting water conditions is still a challenge to be overcome. Thus, it is necessary and urgent to develop research that measure the influence of water stress on the growth, development and propagation capacity of species. Given the above, the objective of this work was to determine the influence of rainfall pulses on reproductive phenophases, production and vigor of seeds of Mimosa caesalpiniifolia Benth. Biweekly flowering and fruiting phenophases were recorded in selected plants in the field, and later these observations were correlated with climatic data from the region. Already the evaluation of the physiological potential was carried out through a germination test in five lots of seeds harvested from the trees of the phenophases study. Generally, it was observed that the sabiá (M. caesalpiniifolia) produced seeds between the first half of April and the second half of June, and in the second half of August and the first half of September 2021. The reproductive phenology of the sabiá depends on the extension and frequency of rainfall pulses. The pulse extension was favorable to the physiological potential of the seeds as the germination ranged from 85 to 96%. Therefore, M. caesalpiniifolia has its phenology and productive potential influenced by precipitation pulses.

Terrestrial Orchid Diversity in Sagara Taluk of Shimogga District Central Western Ghats Region of Karnataka

The current article evaluates the study of terrestrial orchids in Sagara taluk of Shimogga district, reports total 26 terrestrial orchid species in Sagara taluk region Shimogga district Karnataka from the period of January 2019-January 2022 and provides information on their distribution, phenology aspects and biological status in the district. Extensive field surveys were carried out periodically in different part of the taluk particularly in grasslands and hilly region to study the diversity and phenological character of the plant. It was noticed that, when compared to other species, the Habenaria species is richly distributed in Sagara taluk regions. During field visits also noticed some anthropogenic activities highly effects on the diversity of the terrestrial orchids. The further study has to be carried out to get more information related to diversity and current status of terrestrial orchid species in Sagara taluk region of Shimogga district Karnataka.

Diel variation in insect‐dominated temperate pond soundscapes and guidelines for survey design

Abstract Passive acoustic monitoring has been used for decades as a non‐invasive tool for quantifying biodiversity in terrestrial and marine ecosystems. Recently, there has been increased interest in the potential for the method to survey freshwater biodiversity. Fundamental aspects of freshwater soundscape phenology, however, often remain poorly understood, despite their importance for suitable survey design. To gain a greater understanding of daily acoustic variation in aquatic insect‐dominated temperate pond soundscapes, 840 hr of underwater sound recordings were collected from five ponds in the southwest of the U.K. We calculated six commonly used acoustic indices to investigate diel trends and evaluated the suitability of each acoustic index to identify biologically complex pond soundscapes. In addition, macroinvertebrates were collected from each pond to investigate potential drivers of diel soundscape variation. The ponds studied possessed clear patterns of daily acoustic variation, with acoustic activity typically peaking between 02:00 and 04:00 and around the solar noon. Acoustic Entropy showed the greatest variation between day and night soundscapes and was best suited for detecting overall daily acoustic variation in the study ponds. However, the Normalised Difference Soundscape Index and the Bioacoustic Index captured strong diel variation in aquatic insect‐dominated soundscapes. Furthermore, we calculated that a minimum hydrophone deployment time of 24 hr is required to ensure that soundscape variation is adequately captured. This study provides an increased understanding of daily acoustic variation in insect‐dominated temperate pond soundscapes, enabling us to provide guidelines for the design and implementation of future passive acoustic monitoring surveys. We suggest that a minimum of 24 hr is required to adequately capture pond soundscape variation. This will increase the chance of detecting key soniferous species in the soundscape and enable more accurate assessments of temperate pond soundscapes.

Urbanization and plant diversity influence different aspects of floral phenology

Plant phenologies can shift as global temperatures rise and landscapes become human-dominated. Some of the most pronounced shifts in phenologies have been documented in urban areas, where surface temperatures can reach 5–7℃ warmer than surrounding rural areas. In this study, we examined how floral phenology—the initiation, peak, and duration of floral events — shifted in grasslands across an urbanization gradient in Louisville, Kentucky, a city with one of the most severe urban heat islands in the US. Our objectives were to understand (1) how urbanization influences floral phenology (2) whether high-quality habitats with increased habitat patch size and plant richness could offset some effects of urbanization, and (3) whether species responses varied across seasons. We found that average first date of flowering and peak abundance date occurred 1–2 weeks earlier in urban compared to rural areas. However, we found that floral duration was longest in sites with high plant richness, regardless of urbanization. We also found that summer-flowering species increased their floral duration in urban areas while spring and fall-flowering species shortened theirs. These differences in seasonal responses lead to an “urban summer spillage” effect where summer-flowering species are able to move into the temporal niche of spring and fall species in urban habitat patches. These shifts could lead to a reshuffling of communities and novel plant-plant competitive interactions or plant-animal interactions in the urban core, with lasting implications for urban conservation.

Insights into sexual reproduction and morph compatibility of the distylous Nymphoides fallax Ornduff (Menyanthaceae)

Nymphoides fallax Ornduff (Menyanthaceae) is an aquatic distylous plant endemic to the Mexican and Guatemalan highlands. Although vegetative reproduction is frequently reported for Nymphoides species, evidence suggests a high prevalence of sexual reproduction in N. fallax. This study aimed: (i) to test homomorphic self-incompatibility, (ii) to describe aspects of floral phenology, estimate the pollen/ovule ratio and the viability of pollen grains, (iii) to evaluate floral morph proportion in natural populations, and (iv) to identify the assemblage of floral visitors, estimating their frequency and capacity to transport N. fallax pollen. The studied populations were located in Central Mexico. We carried out a controlled pollination experiment with eight treatments (n = 80), and we also estimated pollen/ovule ratio and observed floral phenology aspects. We counted the proportion of floral morphs in seven natural populations and observed the presence of visitors to 891 flowers in three natural populations. We observed pollen on the insects using scanning electron microscopy. Our findings showed that N. fallax has diurnal flowers with one-day anthesis, high stigma receptivity, high pollen viability, and intramorph self-incompatibility. The average pollen/ovule ratio (5.1 × 103) was consistent with xenogamy. Five natural populations were found to have both morphs in approximately equal proportions, and two populations consisted only of the long-style morph. An assemblage of 28 floral visitor taxa was observed in 944 visits. The most frequent visitors were exotic bees (Apis mellifera: 43.5 %) and native dipterans (Ephydridae family: 33.3 %; Stratiomyidae and Syrphidae: 7.2 %). Pollen grains were observed attached to the bodies of the most frequent visitors, suggesting that they are potentially effective pollinators. This research expands the knowledge of heterostylous syndrome and sexual reproduction in N. fallax.

Seasonal Ecosystem Productivity in a Seasonally Dry Tropical Forest (Caatinga) Using Flux Tower Measurements and Remote Sensing Data

The Caatinga dry forest encompasses 11% of the total continental territory of Brazil. Nevertheless, most research on the relationship between phenology and ecosystem productivity of Brazilian tropical forests is aimed at the Amazon basin. Thus, in this study we evaluated the seasonality of ecosystem productivity (gross primary production—GPP) in a preserved Caatinga environment in northeast Brazil. Analyses were carried out using eddy covariance measurements and satellite-derived data from sensor MODIS (MODerate Resolution Imaging Spectroradiometer, MOD17 and MOD13 products). In addition to GPP, we investigated water use efficiency (WUE) and meteorological and phenological aspects through remotely sensed vegetation indices (NDVI and EVI). We verified that ecosystem productivity is limited mainly by evapotranspiration, with maximum GPP values registered in the wetter months, indicating a strong dependency on water availability. NDVI and EVI were positively associated with GPP (r = 0.69 and 0.81, respectively), suggesting a coupling between the emergence of new leaves and the phenology of local photosynthetic capacity. WUE, on the other hand, was strongly controlled by consecutive dry days and not necessarily by total precipitation amount. The vegetation indices adequately described interannual variations of the forest response to environmental factors, and GPP MODIS presented a good relationship with tower-measured GPP in dry (R2 = 0.76) and wet (R2 = 0.62) periods.

The importance of including phenology when modelling species ecological niche

Species distribution models have grown in complexity by incorporating fine‐scale variables, including data on microclimate, physiology and species interactions. Recent studies have acknowledged the importance of the spatial scale by including higher resolution maps and more complex climatic variables. However, models rarely consider the consequences of including data related to time. Indeed, species phenology – and potential shifts in phenology due, for example, to climate change – is potentially one of the most neglected aspects of ecological modelling. We present a literature review of relevant phenological aspects at different temporal scales and across several taxa. Such elements should be considered to define better the environmental niche and project present, future and past distribution models. We considered the available studies on plants, insects, reptiles, birds and mammals to evaluate how they dealt with the phenology of the investigated species, as well as the phenology of other resources and interacting species, to infer present, past and future projections. Here we focus on four main phenological aspects that, if not considered, may easily bias any projection, namely: 1) phenology can be accompanied by a shift in distribution within the year (e.g. migratory species); 2) activity may be restricted to a portion of the year (e.g. most ectotherms from temperate climates); 3) survival and reproduction success may depend on the synchrony with other species phenology (e.g. plants–pollinators interactions); 4) changes in climatic conditions can lead to shifts in phenology (e.g. anticipated or delayed blooms or changes in migration timing). In this review, we show how neglecting such factors may quickly lead to project a biased distribution. Finally, we provide a guide on evaluating whether the case study may be affected by such factors and what actions may improve the models.

Paddy lands detection using Landsat-8 satellite images and object-based classification in Rasht city, Iran

Rice is one of the most important food staples in many countries, particularly Iran. Because irrigated rice production differs from other agricultural fields, this study developed a paddy field mapping model based on phenological aspects, various satellite sensor data, and an object-based approach. This study uses the phonological features of rice plants as well as annual data on land surface temperature (LST) to produce the paddy map. The core remote sensing data consists of the yearly LST from MODIS and multi-temporal Landsat-8 satellite imagery. The detection of phenological characteristics and the selection of relevant Landsat images were made possible by analyzing the LST time series with Google Earth Engine. After that, object-based image classification and fuzzy functions are used to create flexible and comprehensible rules for discovering paddy fields in Rasht, Iran. Data such as the digital elevation model (DEM) and spectral indices including NDVI, EVI, and LSWI were employed to improve the object-based classification. Due to the unique properties of paddy lands, a DEM of 12.5 m obtained from the ALOS PALSAR sensor could help distinguish paddy lands from other vegetation. A comparison finally made between the object-based and pixel-based classification methods showed that the former is more accurate. Overall accuracy and kappa coefficient for the pixel-based classification approach were 92% and 0.89, respectively, whereas overall accuracy and kappa coefficient for the object-based classification method were 94% and 0.92, respectively. Eventually, the producer's accuracy of the paddy class has increased from 88% to 94%.

The Arctic tern Sterna paradisaea: consistency and variability in spatial use at a global oceanographic scale

Elucidating the ecological factors underpinning migratory strategies of seabirds is necessary for understanding resilience to environmental change. Arctic terns Sterna paradisaea breed in the Northern Hemisphere and are unique for the global scale of their migration. Geolocator data from 37 Arctic terns breeding in a low-latitude colony, 10 of which were re-tagged in successive years, were analysed to characterise their migratory behaviour and to test the hypothesis that individuals have repeatable migration strategies. Seawater immersion data suggested a fly-forage strategy, with birds remaining on the wing at night and only foraging during daylight. Southward movement was focused initially along Atlantic eastern-boundary upwelling systems. Most terns then reoriented eastwards, crossing the southern Indian Ocean before moving south to the Antarctic. Foraging intensity differed between migration phases. Indian Ocean foraging locations were diverse, and less frequent over deep ocean basins. Foraging intensity was highest in the later stages of return migration, particularly in and around the Azores Confluence Zone. High movement speeds and foraging intensity on return migration may be adaptations to optimise reproductive success. Some aspects of migration phenology were repeatable between years, but trajectories were displaced by wind. Repeat birds did not use the same foraging areas in different years, and their trajectories across the Indian Ocean also differed. The results of this study suggest that the Indian Ocean crossing is a behaviour pattern, surviving since the last ice age, enabling Arctic terns breeding at low-latitude northwest European colonies to arrive at fragmenting Antarctic sea ice when foraging conditions are suitable.

Growth response of coniferous trees to climate change in the Qinling Mountains, China

As an important geographical boundary, the subalpine coniferous forests in the Qinling Mountains have critical effects on water conservation, biodiversity conservation and climate regulation at the regional and even larger scale. In recent decades, temperature significantly increased in the Qinling Mountains, with significant spatial heterogeneity. An understanding of the responses of the Qinling coniferous trees to climate change is important for the protection and management of mountain forests under climate change. In this study, we synthesized the relationships between the radial growth of coniferous trees and climate at different altitudes in the western, central, and eas-tern Qinling Mountains. The effects of climate change on coniferous trees were investigated from the aspects of radial growth, NDVI, phenology, and species distribution range. Furthermore, know-ledge gaps in the responses of tree growth to climate change and possible future directions in this field were discussed.