Understanding the distribution of mangrove species is crucial for the long-term monitoring and conservation planning of mangrove ecosystems. In this regard, Species Distribution Models (SDMs), especially the Maximum Entropy method (Maxent), has been widely used to map out the geographic distribution of species. However, only a few studies have applied this approach to investigate mangrove species distribution in the Bangladeshi Sundarbans, part of which is designated as a UNESCO World Heritage Site. To address this, we employed Maxent species distribution model to evaluate the environmental suitability of six major mangrove species with the view of identifying the major factors that determine their geographical spread in the Bangladesh Sundarbans. We selected a total of twelve environmental variables for final model development. Our findings indicated that the north-eastern Sundarbans boasted a high richness of species, whereas the south-western exhibited the lowest due to a likely increase in salinity. These two areas should be prioritized for further monitoring to better comprehend species composition and potential shifts therein in response to future changes in the climate. The species-richness and community map developed in this study can serve as a valuable resource for policymakers in establishing conservation and management zones for mangroves in the Bangladeshi Sundarbans.
This study was conducted in the Letkhokkon delta mangrove, Myanmar to establish species-specific allometric models for accurate aboveground biomass estimation, contributing to improved mangrove ecosystem management. We found three mangrove species (Avicennia officinalis, Sonneratia apetala and Sonneratia caseolaris), and the first two species (A. officinalis and S. apetala) were dominant. Results highlighted the distinctive stand structure, species composition, and the low Shannon diversity (H '=0.734). Using the tree measurable parameters such as diameter at breast height (DBH), height (H) and wood density (rho), we established several allometric models of aboveground biomass (W=axb) for two dominant species. We selected the best-fit allometric models by model selection parameters. Also, we compared these best-fit models with the previously reported allometric models. Our study found that volumetric parameter (DBH2H) and rho DBH2H gave the best results with relatively higher accuracy than the other explanatory parameters. The study confirmed the importance of rho in building of site-specific allometric model and also validated the superiority of species-specific models over generalized equations to estimate the biomass accurately. Besides, comparisons with other allometric models for mangroves in Americas, Asia, China and Myanmar emphasized the significance of tailored approaches, considering the influence of rho on accurate biomass estimation. Wood density showed less significance in species-specific level though rho was an important variable for generalized models. Applying ANOVA results for model comparison, the current models did not significantly differ from the previous ones. Furthermore, the mean biomass differences of current study were the least variations from the observed data among other models. It pointed out site-and species-specific models reduce the uncertainties of biomass and carbon stock estimations in comparison with the generalized models. Using the best-fit models, aboveground biomass of Avicennia officinalis stand were estimated as 13 Mg ha-1 and Sonneratia apetala stand, 14 Mg ha-1 of carbon. In conclusion, our study established the site-and species-specific equations for estimating mangrove biomass in Myanmar, with implications for Greenhouse gas (GHG) accounting and emission reduction.
Dryobalanops beccarii is an important species for reforestation and produces durable timber in tropical regions. A reforestation site planted with D. beccarii was established in Sarawak, Malaysia, in 2005, where logging and shifting cultivation had previously occurred. To promote D. beccarii growth, a selective girdling silviculture treatment (debarking below breast height) was experimentally applied to the most dominant pioneer trees, Macaranga gigantea in 2012. In this study, the growth characteristics (stem diameter and tree height) and wood properties (basic density and compressive strength parallel to the grain) of 20-year-old D. beccarii were investigated approximately a decade after the girdling treatment. D. beccarii trees grown in the girdling plot exhibited (1) significantly greater stem diameter and tree height, and (2) similar basic density and compressive strength compared with those in the control plot. In addition, trees with faster radial growth had higher basic density and compressive strength in D. beccarii. These findings indicate that the girdling treatment of pioneer trees can enhance the growth performance of planted D. beccarii without deteriorating its wood quality.
To identify the functional traits of fine roots in mangrove species, we evaluated the root respiration rate and morphological traits, namely mean root diameter, specific root length (SRL), and root tissue density (RTD), using the root branching order classification in the two mangrove species. Although root respiration rates varied widely (0.63-12.76 and 0.42- 6.55 nmol CO2 g-1 s-1, respectively), there was a trend toward higher respiration rates for the smaller diameter roots. Only root respiration rates of first-order roots of Bruguiera gymnorrhiza were significantly higher than those of higher order roots. There were differences in SRL, RTD, and root diameter between first two order roots and forth-order roots of both species, except for SRL of second-and forth-order roots of B. gymnorrhiza. First-order roots of Rhizophora stylosa differed significantly from that of B. gymnorrhiza in respiration rate, SRL and RTD, showing the characteristics of species. Fine root respiration and morphological traits by order classification may reflect differences in the functional traits of roots. Further research on the physiomorphological differentiation of fine roots would improve our understanding of various tolerance and adaptation strategies for environmental stress, among mangrove species.
The leaf and root tip traits of tree species have evolved to acquire resources, such as light, water, and nutrients, in their habitats. Understanding the relationships between leaf and root tip traits and growth environments provides critical insights to predict tree community responses to environmental change. The aim of this study was to elucidate the differences in leaf and root tip traits among tree species and their relationships with topographic differences in subtropical trees. We measured four leaf traits (specific leaf area, thickness, area, and nitrogen concentration) and four root tip traits (specific root tip length, tissue density, diameter, and nitrogen concentration) and analyzed the difference in leaf and root tip traits between tree species specifically growing on ridges (ridge species) and in valleys (valley species) and the relationships among the traits. Leaf traits differed between ridge and valley species, whereas root tip traits did not differ. Ridge species formed small, thick, low-nitrogen leaves, which are possibly associated with high dry and wind stress tolerance, whereas the valley species formed broad, thin, high-nitrogen leaves, which may be associated with high light-acquisition efficiency. These patterns reflect a trade-off between resource acquisition and stress tolerance for leaf traits. Furthermore, the relationships between leaf and root tip traits were confirmed only for the nitrogen concentration: the leaf nitrogen concentration was positively correlated with the root tip nitrogen concentration. This result implies that tree species optimally balance photosynthetic activity with nutrient-and water-absorption activities by varying nitrogen concentrations.
This research explores the sustainable management of sacred groves in Meghalaya, India, using an original framework that integrates Ostrom's (1990) eight design principles with six additional principles proposed by Lyngdoh and Mawlong (2022). It also reexamines commons theory, particularly Ostrom's framework, through the lens of sacred groves, a subject rarely addressed in existing commons literature. Based on findings from three case study sites, the research identifies key institutional, cultural, and spiritual factors underpinning effective commons governance. Although formal governance appears multi-layered in Meghalaya, the actual management of sacred groves is predominantly carried out by traditional governance systems led by the Chiefs of the Hima and village leaders, who hold strong legitimacy. These systems, rooted in customary law, enable community-based stewardship through shared responsibilities and ritual practices. This research underscores the importance of formally recognizing and integrating traditional institutions with statutory conservation frameworks. The principle of deep ecology, a strong belief in divine retribution and spiritual reverence for nature, emerges as a decisive factor promoting selfregulation and adherence to customary rules. This internalized belief system significantly reduces the need for external monitoring, graduated sanctions, or conflict resolution mechanisms, as outlined in Ostrom's principles. Theoretically, this study challenges conventional commons theory to more fully incorporate cultural and spiritual dimensions. It argues that faith-based values and traditional belief systems play a vital role in sustaining natural resource governance, particularly in sacred landscapes, and should therefore be included in future theoretical and policy frameworks.
Mangroves are important tropical coastal ecosystems providing various ecosystem services such as carbon sequestration, coastal protection, mitigation of storm winds and surges, as well as serving as habitat for various organisms, etc. However, huge areas of mangroves were already lost because of anthropogenic activities such as conversion of mangrove to aquaculture ponds in the last half century. Therefore, numerous countries like the Philippines have made an immense effort to restore the lost mangroves by replanting. One of the threats to mangrove reforestation is the damage caused by burrowing of marine isopods Sphaeroma terebrans, i.e. the holes created by isopods in the mangrove trunk can cause mangrove trees to fall. In the present study, for three mangrove species, Avicennia marina, A. alba, and Sonneratia alba, isopod hole density at the trunk surface and decay extent of trunks were measured at a recovering forest in Batan Estuary, Aklan, Philippines. The trunk decay was evaluated using acoustic tomography by measuring the travel times and attenuation of the sound wave within the focal trunk. Also, we attempted to clarify the relationships among isopod hole density, trunk decay extent and relative height from mean lower low water (MLLW) level. The hole density decreased significantly with increasing time of exposure to the atmosphere (height relative to MLLW). The trunk decay area increased with decreasing relative height above the MLLW level in A. marina, but did not decrease significantly in the other tree species. The relationship between trunk decay volume and hole density was insignificant, but A. marina had a higher trunk decay volume than the other two species. The present results partially supported our hypothesis that trunk decay extent is a function of isopod hole density on the trunk surface, as well as the species of the host tree, i.e. interspecific differences in trunk decay area and volume were detected but the effect of hole density on the trunk decay volume was insignificant. The holes caused by isopods could be a trigger to start the formation of hollow space in the trunks but further research on the other influential parameters, such as tolerances to water quality, xylophagous fungus and physical disturbance, would be necessary to understand the decay process of mangrove trunks considering their interspecific differences.
Le motif du remords est discriminant dans la caractérisation des monarques qui peuplent les tragédies et tragi-comédies du xviie siècle, dont il permet d’établir une typologie. Au bas de cette échelle éthique et politique se trouvent les monstres et les bourreaux d’eux-mêmes, qui mettent en accord éthique et politique à leur propre détriment : les premiers ne suscitent cependant pas la pitié, contrairement aux seconds. Les coupables repentants peuvent, quant à eux, rester sur le trône : ces miraculés n’accèdent pas pour autant à une véritable consécration, car la politique est alors inféodée à l’éthique. À l’inverse, cette dernière s’efface devant la première quand l’État risque la ruine et que le monarque coupable accède malgré tout à une consécration pleine et entière après avoir rejeté le remords. Ainsi, les dramaturges du xviie siècle jouent avec des limites qui, dans le monde réel, sont censées rester contraignantes.
Parmi toutes les délicatesses de la fiction galante (ici, celle de Lafayette et de Bernard) le remords tient une place de choix. Escorté par la honte, qui impose le regard d’autrui en juge de son action, et non loin du scrupule, qui accompagne l’inquiète délibération sur la conduite à tenir, il envahit les aventures intérieures des nouvelles. S’il définit un moment (celui, majoritairement, de psycho-récits à la fois pathétiques et judiciaires) et une temporalité (celle de la répétition), il révèle surtout la part de mauvaise foi en ces personnages responsables de leur irresponsabilité.
Au XVIIIe siècle, se développe une anthropologie nouvelle : certains auteurs, en amont même des thèses de Rousseau, commencent à penser la nature humaine indépendamment du péché originel et à défendre l’idée que l’homme serait doté d’un sens moral inné. Il en résulte une évolution de la poétique de l’histoire tragique. À l’époque de son âge d’or, l’anthropologie sur laquelle le genre se fondait était déterminée par les dogmes de la chute et de la corruption de la nature humaine. Les remords du criminel n’étaient alors qu’une étape vers sa rédemption, dont il doit manifester la sincérité en supportant avec constance les tourments physiques, notamment sur l’échafaud. Dans les histoires tragiques qui constituent notre corpus, le remords change de statut : preuve que le criminel n’est pas totalement corrompu, il devient en même temps une punition suffisante, et même la seule à être à la mesure du crime, aucun supplice n’étant plus douloureux que les reproches de sa propre conscience.
Dans la « Quatrième Promenade » des Rêveries du promeneur solitaire, Rousseau s’interroge sur le remords ressenti après l’épisode honteux du vol du ruban. Pourquoi cet évènement raconté au livre II des Confessions a-t-il gravé en lui d’« ineffaçables remords », alors que les nombreuses entorses qu’il a pu faire contre la vérité tout au long de son existence ont laissé sa conscience en paix ? Loin d’être anecdotique, ce questionnement conduit à s’interroger plus avant sur le rôle du remords dans l’œuvre de Rousseau. Le sentiment de culpabilité n’est pas seulement l’objet d’une interrogation herméneutique : il s’impose comme une véritable force de déstabilisation qui permet la relance féconde de la pensée.
Dans la société post-révolutionnaire décrite par Balzac dans La Comédie humaine, rares sont les fortunes qui, à la faveur des bouleversements historiques, ne sont pas nées ou n’ont pas prospéré du crime : chantage, usure, tromperie, fraude et meurtre sont autant d’actes immoraux et illégaux par lesquels les personnages de bourgeois se sont enrichis et ont assis leur domination. Parue en 1831 dans La Revue de Paris, la nouvelle L’Auberge rouge se révèle être une fable politique qui illustre parfaitement cette donnée sociale et offre une réflexion sur la façon dont la classe bourgeoise cherche à échapper aux affres de sa mauvaise conscience.
Jusqu’à quel point peut-on laisser les personnages pervers exposer leurs méfaits et leurs passions mauvaises ? Trois romanciers des Lumières ont apporté des solutions originales au traitement des discours des méchants : Courtilz de Sandras dans ses Mémoires de la marquise de Fresne, Challe dans l’histoire de Dupuis qui clôt Les Illustres Françaises, Prévost dans la seconde partie de son Cleveland (1738-39). Le repentir d’une âme coupable : tel est proprement le sujet des confessions ou des aveux devant une autorité judiciaire, politique ou morale. Ces moments rhétoriques sont fortement théâtralisés dans les trois romans : Challe et Prévost optent pour une confession rendue publique, dont la sincérité rend le criminel plus digne de pitié. Prévost et Courtilz cultivent aussi la distanciation humoristique, créant une complicité avec les lecteurs : s’ouvrent ainsi des perspectives novatrices dans la manière de penser de l’intérieur la psychologie du méchant.
En su primera novela Sab (1841), la escritora criolla Gertrudis G. de Avellaneda inicia un proceso constante de estilización de la naturaleza cubana, dentro del molde literario romántico, en consonancia con la exaltación de las pasiones, de la libertad y de una naciente cubanidad. En paralelo con la posición abolicionista, feminista y anticonformista de la autora, nos proponemos analizar la poetización del entorno natural, como característica de su estilo naciente que va elaborándose dentro de una estética asumida como lírica en toda su obra. El énfasis puesto en la novela en una naturaleza hiperbolizada y sublimada, expresa la nostalgia de la escritora y resulta ser una forma de afirmar una doble pertenencia, tanto a su paisaje criollo de nacimiento, como a una poética reivindicada como romántica.
