Vegetative and reproductive phenology of dominant mangrove species: A multi-parametric approach from Indian Sundarbans

doi:10.21203/rs.3.rs-5289302/v1

Download PDF

Research Article

Vegetative and reproductive phenology of dominant mangrove species: A multi-parametric approach from Indian Sundarbans

https://doi.org/10.21203/rs.3.rs-5289302/v1

This work is licensed under a CC BY 4.0 License

You are reading this latest preprint version

Phenology, the timing of different life cycle events of plants, like flushing of new leaves, shedding old leaves, flowering and fruiting are crucial for plant fitness. It is often evolutionarily adapted to maximising utilisation of abiotic conditions and biotic interactions. This study aims to provide first comprehensive report of spatiotemporal variation in phenology of twelve dominant mangrove species from two sites of Indian Sundarbans. Apart from timing, relationship between different phenological parameters; duration, intensity, synchrony etc. and their importance in explaining variation between species was also studied. Significant variation in timing of peak activity was observed for different plant species across all four phenophases. Apart from timing, other phenological parameters like, duration also varied among phenophases with fruiting showing the longest maturation period in mangroves. This in turn constrained the available timing of activity for other phases leading to synchronisation of early season flushing and flowering, enhancing inclusive fitness. Altogether, flushing peaked early in dry season, flowering peaked mid-season, and fruiting peaked during wet season. There was continuous variation, not only in timing, but other parameters like duration, intensity, and synchrony across phenophases that was comparable to those observed in other tropical mangrove communities. Although there was an overall difference in the timing of flushing, flowering, and fruiting, no differences between sites for each species were observed. This study provides significant insight into relationship between timing, and other phenology parameters which might help unravel life-history, and resource acquisition and utilisation strategies of plant species in this vulnerable mangrove communities.

Mangrove

Indian Sundarbans

Phenology

Flushing

Senescence

Flowering

Fruiting

Duration

Intensity

Synchrony

Phenology is the study of timing of various life cycle events as described by Charles Morren in 1850’s (Demaree & Rutishauser, 2011). In plants the timing of events like putting out of new leaves (flushing), flowering and fruiting, not only need to match environmental factors like light availability, water availability etc., but also to the availability of pollinators and dispersers. Plants tend to augment productivity and fitness by matching the timing of their activity with peak availability of all these factors (van Schaik et al., 1993). However, phenology is more than just timing. There are parameters like duration, intensity, synchrony etc. that are also essential for plant fitness (Elzinga et al., 2007; Rathcke & Lacey, 1985). All these parameters, including timing, exhibit significant variation across large spatial scales. There is not only variation in phenology across communities but often, there is significant variation across species in a community (Luna-Nieves et al., 2017). In temperate region, being limited by low temperatures, species mainly initiate flushing and flowering in the spring (Tooke & Battey, 2010). In tropical regions including mangrove ecosystems, however, not being limited by temperature, light and water availability mainly dominates phenology of species (van Schaik et al., 1993).

The insolation-limitation hypothesis (Sun et al., 1996) states that unless limited by water availability, community-wide leafing and flowering peaks in tropical and subtropical forests should coincide with the period of maximal insolation. Therefore, it is expected that phenology of the mangrove species would be mainly driven by light availability. However, mangrove species grow in high salinity regions, and although they do not experience physical drought, species might experience physiological drought (Ball, 1988). As a physiological adaptation, such species tend to reduce water uptake and water expenditure. Besides these, other factors like pH and soil nutrient might also affect production and accumulation of photosynthates, thereby indirectly influence phenology of mangrove species (Torres et al., 2018).

Moreover, apart from the onset dates of events and the peak dates of activity, other aspects depicted by the temporal pattern of phenological activity like duration, frequency, synchrony, mean and maximum intensity, and skewness had not been systematically studied previously. For every phenophase, duration signifies the length of the activity period, frequency quantifies the occurrences within a calendar year, synchrony describes the overlap in timing of events between individuals in a species, intensity measures the magnitude of phenophase activity, and skewness characterizes the distribution of cumulative activity across all individuals of a species throughout an annual cycle. Apart from timing, these parameters play crucial role in plant survival and productivity. For example, reduced water availability may increase the duration of leafless period in some species, reducing the annual accumulation of photosynthates, needed for general growth, flowering and fruiting. Lack of strong environmental cues, leading to reduced flowering intensity and synchrony among conspecifics, may limit mating opportunities and directly impact plant fitness. In tropical mangrove community, as sunlight is the limiting factor for flushing and flowering, therefore, these phenophases may coincide with maximum availability of sunlight. Hence, tend to show activity early in the growing season. This results in higher activity towards the start of the season, and leading to positive skewness. However, these combined effects of light, water, and nutrients on plant phenology, and their interactions, are still not well-understood.

Species growing in wetter sites generally exhibit longer periods of phenophase (Aronson et al. 1992; de Vasconcelos, de Araujo & Lopes 2010). As example, in tropical forests, duration of flowering was around 2.5 months (Morellato et al. 2000). In the context of the same site, species that undergo flushing during the early dry season tend to initiate flowering sooner (Lacerda et al. 2018) and exhibit an extended flowering duration compared to species that flower later in the dry season (Bhat 1992; Crimmins, Crimmins & Bertelsen 2013; Borges, Henrique & Prado 2014). The timing of flushing and flowering is anticipated to be interconnected and influenced by similar environmental cues (van Schaik, Terborgh & Wright 1993). Bawa et al. (2003) found that the duration of flowering is inversely correlated with the frequency of flowering. Moreover, since fruiting occurs after flowering, it is anticipated that their phenological characteristics are interconnected. But there were no similar studies investigated a comparable connection in vegetative phases or explored the correlations between synchrony, intensity, skewness, duration, and frequency.

Given such a gross lack of understanding in phenology of co-existing species, especially in the Indian Sundarbans, this study aims to investigate the various aspects of phenology of several important mangrove species, thereby revealing the relationships between duration, frequency, synchrony, and intra-specific variation in a phenophases. In this context, the following questions were asked:

a) Is there any seasonality of different phenophases at species ensemble, and, what is the timing of their peak activity?

Following the insolation limitation hypothesis, it is expected that phenophases will exhibit a distinct seasonality with their peak timing coinciding with maximum light availability during the dry season.

b) What is the variation of different supplementary parameters of phenology at the species ensemble and across different species?

Species showing timing of peak activity distributed throughout dry season are expected to show significant variation in parameters like duration, intensity, synchrony etc.

c) What is the variation in timing and other phenology parameters across the two sites?

It is predicted that there will be significant difference in phenology parameters among sites with different characteristics like pH, salinity etc.

d) What is the relationship between different phenological parameters and their importance in explaining the variation between species?

Moreover, relationship between these supplementary parameters was studied to understand if and how these parameters influence each other. For example, in case of flushing, it is expected that, species with early activity have a long duration and low intensity and overlap, and thereby low synchrony between individuals. Similarly for flowering, limited resources are likely to impose a trade-off between duration and intensity. Besides duration, intensity, and synchrony, only a few studies have reported skewness of phenology activity. While it is often anticipated that, phenophase intensity curves would follow normal distribution, studies like Thomson (1980) have reported a positively skewed flowering pattern. Thereby, to understand how variation in species activity affects other phenology parameters, relationship between skewness, frequency, duration, intensity, and synchrony was examined. Apart from these, variation in phenology between species in a multivariate space was also studied to understand if different parameters influence variation similarly and what parameters contribute most to such variation.

2.1 Study site

The current study was conducted at two sites of Indian Sundarbans, Baikunthapur (21.90° N, 88.50° E) and Kaikhali (22.01° N, 88.37° E), separated by a coastal distance of about 38 km (Fig. 1). Baikunthapur is situated at the bank of river Thakuran, a tidal estuarine river that originates near Jaynagar. The degree of disturbance of the mangrove patch of this area is moderate to low. Another study site, Kaikhali is situated at the bank of river Matla. In contrast to Baikunthapur, Kaikhali is a tourist spot and is subjected to higher degree of anthropogenic interferences, and both sites are subjected to heightened fluvial erosion. The dominant mangroves in these sites include Avicennia, Excoecaria, Bruguiera, Ceriops, Rhizophora etc. Kaikhali is richer in terms of species diversity than Baikunthapur (Table S1). The sites have moderate temperature throughout the year with December and January being the lowest at around 24°C. The temperature rises in the summer and is highest during April to June, with mean temperature rising to 33°C (Fig. S1a). The sites receive about 2000 mm of rainfall annually, with most of it occurring between June to October. Both July and August receive the highest rainfall of above 450 mm. The sunshine hour is lowest in monsoon, during June to September, it gradually increases from October and peaks towards the end of the dry season, during April and May (Fig. S1b). There was no substantial spatiotemporal variation in soil or water salinity and pH (Table S2-S3).

2.2 Phenology monitoring

The study was conducted between March, 2021 to February, 2022. Sampling was done monthly, around the middle of each month. At each site, an accessible patch of continuous mangroves was selected. In the patch, mangrove species were sampled until no new species were found. For each species, a minimum of 5 individuals were marked whenever possible. For more abundant species, sampling was restricted to a maximum of 10 individuals at each site. However, for rarer species, the minimum number was relaxed in favour of inclusion of the species. This sampling led to a total of 73 individuals form 12 species across the 2 sites (Table S1). All phenology observations were conducted by same observer to avoid observer bias. Phenology was monitored by direct visual observation of the canopies. The vegetative (flushing and senescing) and reproductive (flowering and fruiting) phenology of individuals were recorded. The canopy fullness was measured in a semi-quantitative scoring of phenology, as a percentage of maximum canopy ranging between 0 to 100 percent in steps of 5 percent (Ouédraogo et al., 2018). Here 0 represents absence of a phenophase while 100 represents the maximum possible activity of the phenophases in the canopy.

2.3 Phenology parameters

Annual cycle of events that repeat across years lie on a scale where December of one year is closest to January of next year. Thus, a zero point on such a scale is arbitrary. Hence, any calculation involving timing needed to be done through a branch of mathematics called circular statistics. The overall species phenology was described as the percentage of species in a phenophase in each month. For comparison across species, an activity period was calculated for each phenophase of each species. It was estimated as the earliest and latest month of observation when at least 20% of individuals have started and stopped the activity, respectively. Within this activity period, Rayleigh's test for uniformity was used to test if activity in a phenophase is uniform throughout the year. If different from a uniform distribution, a mean angle, weighted by activity score, representing peak activity, was calculated using circular statistics (Zar, 2010). The start date was defined as the date with activity of any intensity following a date with no activity. Similarly, stop date was defined as the date of no activity following a date with activity. In case of multiple starts and stops in an annual cycle (referred to as bout), the event corresponding to maximum intensity for the species was defined as the primary phase. The start and stop dates for the primary phase was used as the start and stop dates for the individual. The duration of activity was calculated as the number of days between the start and stop dates. Intensity was calculated as average measure of activity score (in percentage of canopy) of a phase across the duration of activity in a year. Synchrony was calculated as the overlap in duration between pairs of individuals following Augspurger (1983) (Fig. S2). All phenology parameters were averaged across individuals to obtain a species mean.

2.4 Statistical analysis

The species parameters were checked for departure from normality using the Kolmogorov-Smirnov test with Lilliefors correction. Variables were transformed as necessary. Difference between the mean angle of sites was tested using ‘Watson-Williams’ test from the package “circular” in R. One-way ANOVA was used to test for differences in the linear phenology parameters like duration, intensity, and synchrony between the sites. Principal component analysis (PCA) was used to understand relative contribution of different phenology parameters towards the overall variation in phenology between species.

3.1 Phenology of the species assemblage

Seasonal variation in species activity was calculated as the percentage of species in activity across the year. Flushing (z = 10.16, p < 0.001) and senescing (z = 8.22, p < 0.001) phenophases passed the Rayleigh's test of uniformity, indicating that the species had a distribution of peak timing that was different from uniform (Fig. S3). Senescing peaked on 20th of October while flushing peaked almost 3 weeks later, on 9th of November. Flowering activity however did not pass the Rayleigh's test (z = 0.21, p = 0.83) indicating that activity was not different from uniform, having activity throughout the year. Fruiting in contrast had an activity different from uniform (z = 8.10, p < 0.001) with peak on 15th of August.

Species varied widely in different phenology parameters of duration, intensity, and synchrony across the four phases (Table S4). Species flushed for more than 4.5 months and senesced for more than 6 months on average. They flowered for more than 2.5 months and fruited for about 4.5 months on average. Although most species had an annual activity cycle, some species showed bi-annual flushing, senescing, and flowering. Fruiting was annual for all species. Intensity was highest for flowering phase, while synchrony of leaf senescence was highest.

3.2 Variation in phenology across species

When considered across species, most species started flushing between September and October, with peak between October to December and ultimately stopping flushing between November and March (Fig. 2). Species like Sonneratia apetala showed biannual flushing activity. Senescence timing was more variable between species than flushing, with start, mean and stop timing spread throughout the year (Fig. 3). Most species started flowering in the dry season between April to June, with peak between May and August and stopping between June to September (Fig. 4). Three species, namely Bruguiera cylindrica, Bruguiera gymnorhiza, and Ceriops decandra flowered throughout the year. Species set fruit between May to September with mean between July to September and disperse between October and January (Fig. 5). Although a few species flowered more than once a year, all species showed a single fruiting activity cycle in a year.

Flushing duration was similar across species. Sonneratia apetala with two flushing bouts had lowest duration of flushing per bout. Xylocarpus mekongensis also had lower duration but highest intensity of flushing activity. Flushing synchrony was high from all species in the study site (Fig. 6a). Species senesced leaves for longer duration and lower intensity overall than flushing activity. Avicennia marina shed leaves for about 10 months of the year (Fig. 6b). Bruguiera gymnorhiza had the longest flowering duration and Aegialitis rotundifolia had the highest synchrony (Fig. 7a). Bruguiera cylindrica fruited for the longest duration and with highest synchrony between individuals (Fig. 7b).

3.3 Variation in phenology across sites

While considering all twelve species, there were significant differences in the timing of flushing, flowering, and fruiting between the two sites (Table S5). Flushing of species in Baikunthapur peaked around 30th of October while those in Kaikhali peaked more than 2 weeks later, around 15th of November. Although senescence peak in Kaikhali was about a month later than Baikunthapur, it was not significantly different across the two sites. Extended flowering in some species in the Kaikhali site led to a large variation in peak flowering across the two sites. While peak flowering in Baikunthapur occurred around 28th of July, peak in Kaikhali occurred over 4 months later, around 5th of December. Similarly, fruiting peaked around 7th of August in Baikunthapur and more than 2 weeks later around 25th of August in Kaikhali. However, looking at species that were common across both sites, only Sonneratia apetala senesced later and Avicennia marina fruited later in Kaikhali than in Baikunthapur (Table S5).

In contrast to the variation in timing, overall, the duration, intensity and synchrony of flushing were similar across the two sites (Table S6). However, Avicennia alba flushed with a lower intensity in Baikunthapur than in Kaikhali. The same trend follows in senescing as well. However, the intensity of Avicennia alba was lower but Sonneratia apetala was higher in Baikunthapur than in Kaikhali (Table S7). The flowering intensity of Avicennia officinalis was higher in Baikunthapur (Table S8). Fruiting intensity of Avicennia marina was lower but Avicennia officinalis was higher in Baikunthapur (Table S9). Thus, although intensity of some species varied across the phenophases, there was no variation in duration or synchrony.

3.4 Relationship between phenology parameters

For flushing (Fig. S4), Augspurger was positively correlated with duration (0.53) and intensity (0.63) negatively correlated with kurtosis (-0.56). For Senescing (Fig. S5), frequency was positively correlated with skewness (0.70). For flowering (Fig. S6), frequency was strongly correlated with Augspurger (0.78) and moderately correlated with skewness (0.64). Augspurger was moderately correlated with skewness (0.62), on the other hand, skewness was strongly correlated with kurtosis (0.69). Lastly, for fruiting (Fig. S7), frequency is strongly correlated with Augspurger (0.93). Furthermore, duration of fruiting was moderately correlated with frequency (0.66) and Augspurger (0.68).

3.5 Relative importance of phenology parameters

For this specific study, the relative contribution of each of the phenology parameters towards total variation in phenology across species was analysed. For flushing, PC1 contributed 42.9% of variation whereas PC2 contributed 25.3% of variation (Fig. 8a). Among PC1, Augspurger (28.81) was the highest followed by Kurtosis (23.20) whereas in PC2, the frequency (44.47) and duration (40.75) of flushing were the parameters that contributed the most.

On the other hand, for senescing, PC1 contributed 34% of variation whereas PC2 contributed 23.5% of variation (Fig. 8b). Among PC1, Skewness (34.91) was the highest followed by frequency (29.99) while in PC2, the Augspurger (44.14) and kurtosis (30.73) of senescing were the highest parameters.

For flowering, PC1 contributed 51.1% of variation whereas PC2 contributed 26.3% of variation (Fig. 8c). In PC1, skewness (28.33) was the highest followed by frequency (23.25) whereas in PC2, the duration (49.46) and intensity (40.75) of flowering were the most contributed parameters.

Finally, for fruiting, PC1 contributed 45.6% of variation whereas PC2 contributed 24.9% of variation (Fig. 8d). Among PC1, Augspurger (34.51) and frequency (32.20) were the most contributed variables whereas in PC2, the skewness (57.30) and kurtosis (23.14) were the most important parameters.

4.1 Phenology of the assemblage in relation to abiotic environment and biotic interactions

Flushing and senescing activity of the species assemblage had a distinct seasonality of activity in our study site. Senescence activity peaked during the onset of the dry season while flushing of new leaves peaked about a month later. This timing coincided with the period of increasing solar insolation post-monsoon in the study site. This might enable species with newly flushed leaves to utilise the available light in the dry season (van Schaik et al., 1993), thereby maximising photosynthesis. This also provides further support for insolation-limitation hypothesis, following the expectation that leafing activity of mangrove species would be driven by changes in light availability. Although species in flowering had a distinct peak in the dry season, there was no overall assemblage level mean timing of activity. This was due to some dominant species having continual flowering cycle throughout the year. However, the increased flowering in the dry season might be associated with a general increase in pollinator abundance in tropical forests during the dry season (Janzen, 1967). Fruiting on the other hand peaked in the middle of the wet season in our study sites. Increased water flow during the wet season is thought to facilitate dispersal and seedling establishment (Nadia et al., 2012).

Apart from timing, phenology is defined by several other parameters like duration, intensity, and synchrony. Species assemblage in our study site exhibited a relatively long vegetative activity period with flushing for more than 4.5 months and senescing for more than 6 months of the year on average (Table S4). This duration is longer than those reported from tropical seasonally dry forests (Kushwaha et al., 2010) and comparable to those observed in tropical wet forests (Reich, 1995). Reproductive phenology parameters still have received some attention. Nadia et al. (2012) reported a flowering duration of about 3 months and synchrony of about 0.7 from a Brazilian mangrove community, comparable to what have been observed in the study site. The present study reported duration of fruiting was about 4.5 months, also comparable to that reported in other studies (Upadhyay & Mishra, 2010).

4.2 Variation in timing of activity between species

A review of global literature for report on timing of vegetative and reproductive phenophases of the species in our study site are given in Table S10. In our study area leafing occurred mostly during dry season, except in case of Aegialitis rotundifolia and Excoecaria agallocha, where flushing occurred in wet season and in Bruguiera gymnorhiza and Acanthus ilicifolius, where senescing occurred in wet season. The leafing timing of Avicennia alba and Bruguiera cylindrica was exclusively in the dry season, and differed from that reported in the global literature. Timing of flowering was similar, with peak predominantly in the dry season. However, contrary to other studies (Table S10), Acanthus ilicifolius and Sonneratia apetala flowered in the wet season, while Avicennia alba flowered in the dry season. There is no variation in the overall timing of fruiting, with all the species peaking in the wet season as reported in other studies across the world.

When compared across species, flushing duration, intensity and synchrony showed little variation (Table S6). Flushing synchrony was generally high across species, indicating a greater influence of abiotic factors like light availability in determining flushing activity. Leaf senescence duration was relatively more variable between species. While species like Sonneratia apetala shed leaves for over 3 months, species like Excoecaria agallocha senesced almost throughout the year (Table S5). However, the greater duration of senescence for species might have led to higher overlap between individuals, resulting in highest synchrony among all the phases. Flowering duration also varied greatly between species. Although three species flowered throughout the year, they showed distinct patterns of flowering, leading to different durations. Among them, only Bruguiera gymnorhiza continually flowered all throughout the year with overlapping cycles. Flowering phenophase also had lowest duration and highest intensity among all the phases. Fruiting duration of species was like that of flushing phenophase, but their synchrony was lowest across all phases. This might be due to greater variation on timing of fruit maturation and dispersal between individuals of each species.

4.3 Comparison of timing of the assemblage to other sites

When compared across sites, barring some exceptions, species did not differ significantly in their peak timing of activity. Although the sites were geographically separated, this can be expected since the sites showed negligible variation in their soil salinity or pH values. Also, other abiotic factors like temperature, light and rainfall were similar across the two sites. This might be the reason why other parameters like duration and synchrony were also similar for species between the two sites. Although intensity of phenophases for some species were different across sites, the nature of variation was not consistent across sites and other species did not differ between sites. Thus, to overall conclude, species did not differ consistently between the two sites. However, when species are pooled together, there were significant differences in the timing of flushing, flowering and fruiting phenophases between the two sites. Baikunthapur had peak flushing, flowering, and fruiting earlier than Kaikhali. Species diversity was much lower in Baikunthapur than in Kaikhali (see Table 1). Only 6 out of the overall 12 species were present in Baikunthapur. Thus, the overall timing observed here were dominated by the timing of these 6 species. In contrast, Kaikhali being a more diverse site might have a greater variation in timing across species which might be responsible for this variation in the overall timing when species are pooled together. However, although explicitly not tested, empirical observation suggests Kaikhali experiencing a relatively greater anthropogenic disturbance than Baikunthapur. Indeed, several studies do show the effect of anthropogenic disturbance on plant phenology (Herrerias-Diego et al., 2006), and this can also be a possible factor affecting phenology between the two sites.

4.4 Relationship between phenology parameters

The phenology parameters like duration, frequency, synchrony, and intensity have been investigated independently in separate studies, but their relationships have rarely been explored. In this study, we have seen long maturation period of fruiting of the species. Therefore, dispersion of fruits before rain (Nadia et al., 2012) requires earlier flowering as well as flushing. For this, flushing starts from October, though, intensity of sunlight does not reach its peak during this period, but its high enough for sufficient photosynthesis. Moreover, longer duration of flushing compensates relatively lower availability of sunlight. Eventually, sufficient accumulation of photosynthates causes synchronous flowering early in the season, thereby increasing overall fitness. Positively skewed flowering, as seen in this study, enables longer duration of fruit maturation. Augspurger index of synchrony is mainly dictated by the duration of overlap between individuals. Therefore, higher duration of flushing and fruiting activity might contribute to expected increase in the overlap between individuals.

4.5 Relative importance of phenology parameters

The exclusive examination of phenological parameters in a multivariate space is the first report of such analysis that may help us determine coordinated changes in phenology parameters for different phenological strategies. When examining variation in phenology between species in multivariate space, kurtosis explained most of the variation across all four phases. However, there were four major axes – augspurger / kurtosis, frequency / duration, duration / kurtosis and kurtosis/skewness. Along with a few other parameters, these four sets explained different proportions of the variation across the four phenophases respectively. This lack of similarity in parameters across the phenophases indicate that different phases might be affected differently by environmental cues or constraints. For example, flushing showed high synchronous activity with sharp peak, indicating higher degree of dependency on environmental cues like sunlight. Around spring equinox for example, duration of flushing for species in the study site might be decreased along with increase in intensity and synchrony of flushing. In case of senescence, species showed multiple bouts of activity, each with lower duration, indicating continuous shedding pattern. Physiological stress, like salinity in mangrove ecosystem might result in this kind of activity. In case of flowering, both duration and kurtosis tend towards normal distribution at species level, also indicated high variability across species. This might be due to variation in adaptability of species towards resource acquisition and utilisation, without the presence of a sharp cue. Fruiting activity was defined by broad flat peak which signified longer duration of fruiting at species level. This might ensure sufficient time to mature the fruits and take advantage of the optimum environmental cues for successful germination.

4.6 Conclusion

This study provided the first comprehensive report of plant phenology from direct visual observation of canopies in an ecologically important area like the Indian Sundarbans. This study reported distinct seasonality of assemblage level peaks in vegetative and reproductive phenology, similar to that reported in other tropical mangrove communities. Results also demonstrated significant variation, not only in timing but other important phenology parameters like duration, intensity, and synchrony, that are important but rarely addressed in other studies and barely reported in other mangrove communities. Further, this variation was attempted to be understood in the context of abiotic factors and biotic interactions including anthropogenic disturbance. The results reveal the essential relationships between other parameters like duration, frequency, and synchrony which have rarely received any attention in past studies. Additionally, the results indicate which of these parameters contribute most to the variation in phenology between species. Finally, these results give insight into how variation in activity between species cueing to light versus water gives rise to the overall activity pattern across time. This would serve as a baseline for further studies addressing important biological and ecological questions on plant phenology in mangrove communities in the future.

Ethical Approval:
This declaration is not applicable for this study

Funding:

No funding was received and used in this study

Author Contribution

SC: Conceptualization, Investigation, Supervision, Data Curation, Analysis, Visualization, Software, Writing - Original draft, Writing - Review & Editing; TC: Methodology, Investigation, Formal analysis, Validation, Writing - Original draft, Writing - Review & Editing; TG: Resources, Data Curation; PC: Conceptualization, Supervision.

Acknowledgement

We thank Mr. Niranjan Kuila from Baikunthapur Sishu Seva Kendra (BSSK) and all other locals of Baikunthapur and Kaikhali for their intermittent support.

Augspurger, C. K. (1983). Phenology, Flowering Synchrony, and Fruit Set of Six Neotropical Shrubs [Article]. Biotropica, 15(4), 257–267. https://doi.org/10.2307/2387650
Ball, M. (1988). Ecophysiology of mangroves. Trees, 2(3), 129–142. https://doi.org/10.1007/bf00196018
Bawa, K. S., Kang, H., & Grayum, M. H. (2003). Relationships among time, frequency, and duration of flowering in tropical rain forest trees. Am J Bot, 90(6), 877–887. https://doi.org/10.3732/ajb.90.6.877
Demaree, G. R., & Rutishauser, T. (2011). From "Periodical Observations" to "Anthochronology" and "Phenology" - the scientific debate between Adolphe Quetelet and Charles Morren on the origin of the word "Phenology" [Article|Proceedings Paper]. Int J Biometeorol, 55(6), 753–761. https://doi.org/10.1007/s00484-011-0442-5
Elzinga, J. A., Atlan, A., Biere, A., Gigord, L., Weis, A. E., & Bernasconi, G. (2007). Time after time: flowering phenology and biotic interactions [Review]. Trends Ecol Evol, 22(8), 432–439. https://doi.org/10.1016/j.tree.2007.05.006
Herrerias-Diego, Y., Quesada, M., Stoner, K. E., & Lobo, J. A. (2006). Effects of forest fragmentation on phenological patterns and reproductive success of the tropical dry forest tree Ceiba aesculifolia. Conserv Biol, 20(4), 1111–1120. https://doi.org/10.1111/j.1523-1739.2006.00370.x
Janzen, D. H. (1967). Synchronization of Sexual Reproduction of Trees Within the Dry Season in Central America [Article]. Evolution, 21(3), 620-&. https://doi.org/10.2307/2406621
Kushwaha, C. P., Tripathi, S. K., Singh, G. S., & Singh, K. P. (2010). Diversity of deciduousness and phenological traits of key Indian dry tropical forest trees [Article]. Annals of Forest Science, 67(3), 310–310, Article 310. https://doi.org/10.1051/forest/2009116
Luna-Nieves, A. L., Meave, J. A., Morellato, L. P. C., & Ibarra-Manríquez, G. (2017). Reproductive phenology of useful Seasonally Dry Tropical Forest trees: Guiding patterns for seed collection and plant propagation in nurseries [Article]. Forest Ecology and Management, 393, 52–62. https://doi.org/10.1016/j.foreco.2017.03.014
Nadia, T. D., Morellato, L. P. C., & Machado, I. C. (2012). Reproductive phenology of a northeast Brazilian mangrove community: Environmental and biotic constraints [Article]. Flora, 207(9), 682–692. https://doi.org/10.1016/j.flora.2012.06.020
Ouédraogo, D.-Y., Doucet, J.-L., Daïnou, K., Baya, F., Biwolé, A. B., Bourland, N., Fétéké, F., Gillet, J.-F., Kouadio, Y. L., & Fayolle, A. (2018). The size at reproduction of canopy tree species in central Africa [Article]. Biotropica, 50(3), 465–476. https://doi.org/10.1111/btp.12531
Rathcke, B., & Lacey, E. P. (1985). Phenological Patterns of Terrestrial Plants [Review]. Annual Review of Ecology and Systematics, 16(1), 179–214. https://doi.org/10.1146/annurev.es.16.110185.001143
Reich, P. B. (1995). Phenology of tropical forests: patterns, causes, and consequences [Article; Proceedings Paper]. Canadian Journal of Botany, 73(2), 164–174. https://doi.org/10.1139/b95-020
Sun, C., Kaplin, B. A., Kristensen, K. A., Munyaligoga, V., Mvukiyumwami, J., Kajondo, K. K., & Moermond, T. C. (1996). Tree Phenology in a Tropical Montane Forest in Rwanda [Article]. Biotropica, 28(4), 668–681. https://doi.org/10.2307/2389053
Thomson, J. D. (1980). Skewed Flowering Distributions and Pollinator Attraction. Ecology, 61(3), 572–579. https://doi.org/10.2307/1937423
Tooke, F., & Battey, N. H. (2010). Temperate flowering phenology [Review]. J Exp Bot, 61(11), 2853–2862. https://doi.org/10.1093/jxb/erq165
Torres, J. R., Barba, E., & Choix, F. J. (2018). Mangrove Productivity and Phenology in Relation to Hydroperiod and Physical–Chemistry Properties of Water and Sediment in Biosphere Reserve, Centla Wetland, Mexico. Tropical Conservation Science, 11, 1940082918805188. https://doi.org/10.1177/1940082918805188
Upadhyay, V. P., & Mishra, P. K. (2010). Phenology of mangroves tree species on Orissa coast, India [Article]. Tropical Ecology, 51(2), 289–295. <Go to ISI>://WOS:000275880600015
van Schaik, C. P., Terborgh, J. W., & Wright, S. J. (1993). The Phenology of Tropical Forests: Adaptive Significance and Consequences for Primary Consumers [Review]. Annual Review of Ecology and Systematics, 24(1), 353–377. https://doi.org/10.1146/annurev.es.24.110193.002033
Zar, J. H. (2010). Biostatistical analysis (5 ed.). Pearson Education. https://www.pearson.com/us/higher-education/program/Zar-Biostatistical-Analysis-5th-Edition/PGM263783.html

No competing interests reported.

Supplementarydata.docx

Download PDF

Editorial decision: Revision requested
28 Oct, 2024
Editor assigned by journal
21 Oct, 2024
Submission checks completed at journal
19 Oct, 2024
First submitted to journal
18 Oct, 2024

You are reading this latest preprint version

Vegetative and reproductive phenology of dominant mangrove species: A multi-parametric approach from Indian Sundarbans

Status:

Version 1

Abstract

Figures

1. Introduction

2. Materials and Methods

2.1 Study site

2.2 Phenology monitoring

2.3 Phenology parameters

2.4 Statistical analysis

3. Results

3.1 Phenology of the species assemblage

3.2 Variation in phenology across species

3.3 Variation in phenology across sites

3.4 Relationship between phenology parameters

3.5 Relative importance of phenology parameters

4. Discussion

4.1 Phenology of the assemblage in relation to abiotic environment and biotic interactions

4.2 Variation in timing of activity between species

4.3 Comparison of timing of the assemblage to other sites

4.4 Relationship between phenology parameters

4.5 Relative importance of phenology parameters

4.6 Conclusion

Declarations

Ethical Approval:
This declaration is not applicable for this study

Funding:

Author Contribution

Acknowledgement

References

Additional Declarations

Supplementary Files

Status:

Version 1

Vegetative and reproductive phenology of dominant mangrove species: A multi-parametric approach from Indian Sundarbans

Status:

Version 1

Abstract

Figures

1. Introduction

2. Materials and Methods

2.1 Study site

2.2 Phenology monitoring

2.3 Phenology parameters

2.4 Statistical analysis

3. Results

3.1 Phenology of the species assemblage

3.2 Variation in phenology across species

3.3 Variation in phenology across sites

3.4 Relationship between phenology parameters

3.5 Relative importance of phenology parameters

4. Discussion

4.1 Phenology of the assemblage in relation to abiotic environment and biotic interactions

4.2 Variation in timing of activity between species

4.3 Comparison of timing of the assemblage to other sites

4.4 Relationship between phenology parameters

4.5 Relative importance of phenology parameters

4.6 Conclusion

Declarations

Ethical Approval: This declaration is not applicable for this study

Funding:

Author Contribution

Acknowledgement

References

Additional Declarations

Supplementary Files

Status:

Version 1

Ethical Approval:
This declaration is not applicable for this study