Rainforest Research Articles

Subfossils suggest worse-than-realised losses of small-bodied mammals in northern Australia

Context Examining Australia’s late Quaternary subfossil record can be valuable in assessing whether the current diversity of small-bodied mammals seen across some parts of northern Australia is ‘normal’. Such records are important for establishing baselines for measuring historic changes in communities today and into the future. These datasets are becoming increasingly important, given trajectories in current global climate change, and predicted habitat losses and other potential anthropogenic impacts. Aims The main aim of this study is to utilise the local subfossil record from north-eastern Australia to establish a natural baseline for assessing changes in small mammal communities post-European colonisation. Methods Subfossils of vertebrates and other taxa were recovered from surface deposits adjacent to cave entrances at Broken River, near Greenvale in north-eastern Queensland, and were subjected to taxonomic, taphonomic and statistical analyses. These were then compared with local faunal records from modern surveys to compare differences in faunal communities between past and present. Key results Radiocarbon dating showed that these subfossils are geologically young, dating to approximately the time of European colonisation. We provide evidence for the former presence of extinct species of hopping mice (Notomys spp.) and rabbit rats (Conilurus spp.) in the region. Additional locally extirpated taxa such as Cape York bandicoot (Isoodon peninsulae) and Shark Bay mouse (Pseudomys gouldii) demonstrated considerable range contractions since the deposits accumulated, compared with their current distribution. Independent evidence from subfossil land snails recovered from these deposits is, with two exceptions, all modern-day vine thicket, karst-dwelling species indicating a long-term maintenance of vine thicket habitat. Thus, the loss of several mammal species is unlikely to be the result of habitat loss. Conclusions Analysis of the surface deposits showed that local historic small-mammal communities were much more diverse than are the region’s extant faunas recorded by modern surveys. Many extinctions and extirpations evidently occurred prior to such faunas being recorded as local inhabitants of the region. Implications Our data suggested that post-European colonisation small-mammal losses are likely to be substantially worse than previously realised.

Changes in Vertical Stratification of Neotropical Nymphalid Butterflies at Forest Edges Are Not Directly Caused by Light and Temperature Conditions

Habitat fragmentation and land use changes threaten neotropical habitats and alter patterns of diversity at forest edges. Like other arthropod assemblages, neotropical fruit-feeding butterfly communities show strong vertical stratification within forests, with some recent work showing its potential role in speciation. At forest edges, species considered to be forest canopy specialists have been observed descending to the forest understory, with the similarity in light conditions between the canopy and understory strata at edges hypothesized to be responsible for this phenomenon. We conducted a study using standardized sampling to document and quantify this edge effect, characterize edge and forest strata, and estimate the relative contributions of temperature and light conditions to changes in nymphalid butterfly stratification at forest edges. We found strong evidence of an edge effect in these butterflies and confirmed strong differences in light and temperature, showing that the edge understory differs little from forest canopy conditions. Of 41 species common to both forests and edges, 28 shifted to have a lower canopy probability at the edge, and our model detected a decrease in canopy probability of 0.165. Furthermore, our analysis indicated the relative abundance of canopy taxa increased at the edge, and the tribes Haeterini and Morphini were especially sensitive to edge effects. However, the analyses here did not clearly implicate temperature or light magnitude in causing changes in neotropical nymphalid vertical stratification at forest edges. Instead, our results point to other mediator variables as being important for changes at tropical forest edges. From our data, edge-responsive species can be separated into two different categories, which likely relates to their resilience to anthropogenic disturbance. We also note that structural causal models have a potential place in future work on tropical conservation, given they can provide causal estimates with observational data.

Identification of the arl1 locus controlling leaf rolling and its application in maize breeding

Increasing planting density is one of the most important strategies for generating higher maize yields. Moderate leaf rolling decreases mutual shading of leaves and increases the photosynthesis of the population and hence increases the tolerance for high-density planting. Few genes that control leaf rolling in maize have been identified, however, and their applicability for breeding programs remains unclear. Here we identified a maize abaxially rolled leaf1 (arl1) mutant with extreme abaxially rolled leaves and found that the size of the bulliform cells within the adaxial leaf blade surface increased in the arl1 mutant. Bulk segregation analysis mapping in an F2 population derived from a single cross between arl1 and inbred line Gui18421 with normal leaves identified the arl1 locus on chromosome 2. Sequential fine-mapping delimited the arl1 locus to a 233.56-kb genomic interval containing three candidate genes. Sequence alignment between arl1 and Gui18421 identified an 8-bp insertion in the coding region of Zm00001eb082500, which led to a frame shift causing premature transcription termination in arl1 mutant. Meanwhile, both deep sequencing and Sanger sequencing showed that Zm00001eb082520 was present in Gui18421 but was absent in arl1. A pair of near isogenic lines (NILs) carrying the Gui18421 allele (NILGui18421) and the arl1 allele (NILarl1) were developed, and the leaves of NILarl1 plants had greater light transmission and photosynthetic rate in the middle and lower canopy than did those of NILGui18421 plants under high-density planting. Furthermore, NILarl1 had a higher seed setting rate, more kernels per ear, and an increased kernel weight per ear than NILGui18421, and the grain yield of NILarl1 was not affected as the planting density increased, suggesting that the arl1 locus can be used for genetic improvement of high-density planting tolerance. Taken together, the identification of arl1 and evaluation of yield-related traits for NILGui18421 and NILarl1 provide an excellent target for future maize improvement.

The effects of plant density and duration of vegetative growth phase on agronomic traits of medicinal cannabis (Cannabis sativa L.): A regression analysis.

Empirical data on the effect of plant density (PD) and length of the vegetative phase (DVP) on plant growth, yield, and cannabinoid concentration of medicinal cannabis (Cannabis sativa L.) are still scarce, leading to a lack of specific cultivation recommendations. We conducted two greenhouse experiments to investigate the effect of PD in the range of 12-36 plants m-2 (D-trial) and DVP in the range of 1-4 weeks (V-trial) on plant morphology, biomass growth of individual plant organs, and CBD concentration of individual inflorescence fractions. Empirical models for the relationships between the investigated plant traits and PD/DVP were created using linear regression analysis preceded by a lack-of-fit test. An increase in PD led to a linear decrease in inflorescence yield per plant (p = 0.02), whereas a positive linear relationship was found for inflorescence yield (p = 0.0001) and CBD yield (p = 0.0002) per m2. Total area yields in the D-trial ranged from 119 to 247 g m-2 from lowest to highest PD. DVP showed a positive linear relationship with inflorescence yield on an individual plant (p = 0.0001) and area basis (p < 0.0001) along with most other relevant agronomic traits such as CBD production, plant size and lateral shoot length. Total area yields in the V-trial ranged from 295 to 571 g m-2 from lowest to highest DVP. The yield increase could be linked to the increased inflorescence number per plant rather than inflorescence size. In contrast to expectations, neither PD nor DVP had significant effects on the cannabinoid concentration gradient from upper to lower canopy layers. CBD concentrations in inflorescences from lower canopy layers were reduced by 23% in the V-trial and 46% in the D-trial. However, with increasing PD, the proportion of higher-concentrated inflorescence fractions from upper canopy layers increased from 46% to 68%, while an extension of DVP shifted this proportion only marginally from 45% to 50%. In the context of standardized production, we therefore advocate high-density production systems that increase the proportion of desired inflorescence fractions from upper canopy layers.

High plant density optimizes leaf stomatal traits for accelerating the stomatal response rate at the lower cotton canopy

AbstractPlants are often exposed to fluctuating light from a few seconds to a few minutes due to cloud movements, mutual shading of leaves, and change in the angle of the sun. Slow stomatal response to fluctuating light leads to carbon loss, but the influence of planting density on light fluctuation frequency and on stomatal response and carbon gain has yet to be fully explored. To fill this knowledge gap, we investigated leaf morphology, stomatal anatomy and response rate, nitrogen content, biomass, and yield under low density, moderate density, and high density (HD) of cotton cultivar (Gossypium hirsutum L.). The results showed that higher planting density significantly increased light fluctuation frequency at the lower canopy. Stomatal size significantly decreased with the increase in planting density, while total stomatal density was consistent. Stomatal density had greater plasticity of determining maximum stomatal conductance than stomatal size. Faster stomatal response rate to fluctuating light under HD was attributed to smaller and denser stomata in the abaxial leaf side. Therefore, cotton under HD treatment had faster photosynthetic induction rate under light induction, resulting in greater carbon gain. We conclude that faster stomatal response rate achieved by the optimization of stomatal anatomy, especially the abaxial side, plays a crucial role in obtaining more carbon gain, biomass, and yield under HD cotton field. This finding indicates that selecting varieties with rapid stomatal response traits and planting at appropriate densities may optimize fluctuating light use to achieve higher yields.

Economic Evaluation of the Planting Period and Retting Techniques in the Production of Quality Kenaf Fibre

The quality and quantity of fibre produced in terms of fibre length, tensile strength and fineness could be determined by the planting period and good retting techniques in kenaf. This study was carried out to determine the appropriate time of planting and examined the different retting techniques for enhanced quality fibre for value addition. Five varieties of Kenaf (Cuba108, Ifeken-DI-400, Ifeken100, Ifeken-400 and Tianung-2) were planted at 50cm x 20cm monthly from June to August (June 10, July 10 and August 10) in 5 locations with their coordinates; Ibadan (Transitional-Rain forest, Lat.7.23′N;Long.3.55′); Ilora (Derived savannah, Lat.8.54′N;Long4.54′E); Ikenne (High Rain forest, Lat.6.92′N;Long.9.46′N); Orin Ekiti (Rain forest, Lat.7.49′N;Long.5.14′E) and Kishi (Southern Guinea Savannah, Lat.9.46′N; Long.3.52′E). Gross Margin (GM) analysis was used to determine the profitability and suitability of the different planting periods. The results show that total variable cost (TVC) in Orin Ekiti for each planting time was the highest (₦705,650:00). The least TVC (₦250,000) was from August plantings in Ikenne. The GM value for a sum of ₦701,650 and ₦1,736,400 were obtained from Kishi and Ilora respectively while ₦1,441.750, ₦184,750, ₦1,224,950 were obtained for the months of June plantings in Orin-Ekiti, Ikenne and Ibadan respectively. July and August plantings recorded low GM. The GM value of June planting was significantly higher in all the locations. The results of the retting techniques revealed that chemical retting had a greater efficiency in the processing of fibre while tank retting is technically supported due to its potability and availability.

First report of foliar blight of castor bean caused by Alternaria ricini in Sinaloa, Mexico.

Castor bean (Ricinus communis) is cultivated agriculturally for oil and ornamentally for its bright foliage and seed. Ornamental castor bean has naturalized in many areas of the world, including the state of Sinaloa, Mexico, where it is not planted commercially. In a survey conducted in 2019 in Sinaloa, wild castor bean was found widely affected by a foliar blight with symptoms similar to Alternaria ricini previously described in the United States (Stevenson 1945) and in the state of Chiapas, Mexico (López-Guillén et al. 2015). Sampling was conducted from February to April along roadsides and irrigation canals at 10 sites that were 10-12 km apart. Symptoms consisted of dark lesions < 2 cm dia with occasional concentric rings and coalescing with age. Incidence of disease among sites ranged from 20 to 60%. The severity of disease was greater in the lower canopy where the foliage area diseased (FAD) ranged from 15 to 35%. Ten symptomatic leaves were collected from each site and leaf fragments were plated on potato dextrose agar (PDA) using standard microbiological techniques for fungal recovery. Isolates of long-beaked Alternaria were recovered from 60 to 70% of fragments from each site and representative isolates (1/site) were selected for further studies. Isolates were transferred to Petri dishes containing PDA for characterization of the colony and V8 juice agar (V8A) for examination of the conidia (Simmons 2007). On PDA, colonies were dark olive brown, cottony, subsurface microsclerotia production abundant, and no production of pigments in the medium. On V8A, conidia were produced singly, darkly pigmented, and broadly ellipsoidal. The length and width of mature conidia ranged 70 to 100 µm (avg 88 µm) and 17 to 26 µm (avg 22 µm), respectively, with 2 to 4 transepta and 1 to 3 longisepta. The apical beak length ranged 10 to 125 um (avg 72 µm). Morphological characteristics were consistent with those of A. ricini from commercial castor bean (Simmons 2007). DNA was extracted from each isolate and the GAPDH and calmodulin genes were sequenced using protocol previously described (Lawrence et al. 2013). For each locus, sequences were identical among fungal isolates and representative sequences were deposited in GenBank (accessions OQ868796 and OQ868803, respectively). When compared to the NCBI database by BLASTn, the sequences had 100% identities to A. ricini GAPDH JQ646331 (576/576 bp) and A. ricini calmodulin JQ646230 (772/772 bp). To confirm pathogenicity of recovered Alternaria, all ten isolates were tested on the commercial castor bean cultivar Chinatan in two independent greenhouse trials. Seed was sown one per pot and four plants per isolate were tested. Spore solutions were prepared from V8A plates and spore densities were adjusted to 4 x 104 conidia/ml. At 4 to 5 leaves stage, plants were sprayed with spore solution until runoff, placed in clear polyethylene bags for 48 hr. After 14 dpi, the percentage of FAD ranged from 19 to 80% with significant differences among fungal isolates. Control plants sprayed with water remained healthy. To fulfill Koch´s postulates, the fungus was re-isolated from representative inoculated plants and its identity was confirmed using morphological characteristics. This is the first report of A. ricini causing foliar blight of castor bean in the state of Sinaloa, Mexico. Strategies for managing inoculum from wild castor bean should be developed in advance of increasing commercial castor production in Sinaloa.

Regeneración natural de la selva alta perennifolia en cultivos abandonados de café (Coffea arabica L.) en Veracruz, México

Background: The tropical rain forest (TRF) has been transformed by the land use change. Coffee plantations are part of the landscape, and their abandonment can favor the original vegetation regeneration. Hypothesis: The abandoned coffee plantations protection in TRF favors natural regeneration, allowing the development of secondary forests in different succession phases. Study site: Colipa, Veracruz, Mexico. Two abandoned coffee plantations and a fragment of TRF. Methods: In 24 transects (50 × 2 m), diameters and heights of woody species (DBH ≥ 5 cm) were recorded and measured. In each transect, quadrants (2 × 2 m) were marked to record shrub and seedlings species. Regeneration status was evaluated through densities of seedlings, juveniles and adults. Results: 60 species were recorded. The highest number of species was present in the TRF and the nearby coffee plantation, they were the sites with the most shared species. The other coffee plantation (3 km away) had the highest density of trees while the TRF had the highest bushes and seedlings density. The 50 % of the species characteristic of TRF in the área are regenerating in coffee plantations, while cultivated species showed poor or no regeneration. Conclusions: After more than 25 years of abandonment, the structure and composition of species is similar to the TRF. Abandoned shade coffee plantations contribute to natural regeneration and function as reservoirs of native germplasm for the region.

Filling the gaps: herpetological checklist of Mayombe National Park and Cabinda Province (Angola) shed light on one of the most unexplored corners of tropical Central Africa

ABSTRACT The global environmental crisis has reinforced the importance of improving the documentation of the geographical distributions of extant species. With this aim, species inventories of specific locations or regions are a high priority, especially so in poorly explored areas. Cabinda Province, an Angolan enclave located between the Republic of Congo and the Democratic Republic of the Congo (DRC), represents one of the most enigmatic and poorly explored areas in Africa. No detailed species inventories within its protected areas (namely, Mayombe National Park) exist. Furthermore, this region presents some of the better preserved remanent of primary moist rainforest in West Africa. Although these forests are severely threatened by logging and by the rapid social growth in the area. Therefore, we provide here the first herpetological checklist of Mayombe National Park and Cabinda Province, Angola, to shed light on this underexplored corner of Africa. To obtain the most accurate species identification, we performed detailed morphological examinations and DNA barcoding identifications. As a result, we recorded a total of 76 species of amphibians and reptiles in the area, including four new genera, 19 new distribution records for Angola, and 13 candidate species. This work also provides novel topotypic genetic material from three reptile species (i.e., Agama congica, Panaspis cabindae and Atractaspis congica), that may contribute to revise and solve taxonomic inconsistencies in these different groups. Finally, we identified areas of high species richness, as well as areas with a high number of habitat specialists, thus indicating species more vulnerable to extinction. Therefore, our study allowed us to identify areas that are of special interest for conservation of reptiles and amphibians, primarily focus on species vulnerable to extinction, but also to identify some knowledge gaps that still need further investigation. To conclude, this work not only contributes to an improved understanding of Angolan herpetofauna, but also highlights the importance of the western slope of Central Africa as an important biodiversity hotspot, centre of endemism and potential source of diversification for this group of land vertebrates.

Assessing Forest Resources with Terrestrial and Backpack LiDAR: A Case Study on Leaf-On and Leaf-Off Conditions in Gari Mountain, Hongcheon, Republic of Korea

In Republic of Korea, the digital transformation of forest data has emerged as a critical priority at the governmental level. To support this effort, numerous case studies have been conducted to collect and analyze forest data. This study evaluated the accuracy of forest resource assessment methods using terrestrial laser scanning (TLS) and backpack personal laser scanning (BPLS) under Leaf-on and Leaf-off conditions in the Gari Mountain Forest Management Complex, Hongcheon, Republic of Korea. The research was conducted across six sample plots representing low, medium, and high stand densities, dominated by Larix kaempferi and Pinus koraiensis. Conventional field survey methods and LiDAR technologies were used to compare key forest attributes such as tree height and volume. The results revealed that Leaf-off LiDAR data exhibited higher accuracy in capturing tree height and canopy structures, particularly in high-density plots. In contrast, during the Leaf-on season, measurements of understory vegetation and lower canopy were hindered by foliage obstruction, reducing precision. Seasonal differences significantly impacted LiDAR measurement accuracy, with Leaf-off data providing a clearer and more reliable representation of forest structures. This study underscores the necessity of considering seasonal conditions to improve the accuracy of LiDAR-derived metrics. It offers valuable insights for enhancing forest inventory practices and advancing the application of remote sensing technologies in forest management.

Effect of Potassium Optimization on Wheat Drought Tolerance in Controlled Conditions

Potassium is an essential nutrient that influences key processes in plants, including osmotic regulation, photosynthesis, and nitrogen assimilation. This study investigated the drought tolerance of wheat (Triticum spp.) plants treated with sufficient potassium (SK, 1 mM) and low potassium (LK, 0.05 mM) under PEG-induced drought stress. Plant physiological development, canopy temperature, photosynthetic efficiency, antioxidant defense enzymes, and nitrogen assimilation enzymes were assessed. In non-drought conditions, LK increased canopy temperature and reduced dry matter yield and photosynthetic performance, with these effects becoming more pronounced under drought stress. SK-treated plants exhibited higher biomass, chlorophyll content, maximum quantum efficiency of photosystem II, and lower canopy temperatures, even under drought conditions. Furthermore, LK restricted the accumulation of key osmotic regulators, including proline, amino acids, and soluble sugars. Under drought stress, LK plants also showed increased hydrogen peroxide and superoxide anion levels, while SK plants had lower reactive oxygen species accumulation and higher antioxidant enzyme activities (catalase and superoxide dismutase). Additionally, LK resulted in reduced activity of nitrogen assimilation enzymes (nitrate reductase, NR, and nitrite reductase, NiR) under both normal and drought conditions. In contrast, SK-treated wheat seedlings maintained higher NR and NiR activities and higher soluble protein content during drought stress. These findings underscore the critical role of potassium management in enhancing wheat yield, particularly in water-scarce regions, as optimal potassium supply strengthens essential physiological and biochemical mechanisms that improve plant tolerance to drought stress.

Accumulation of sodium and manganese during litter decomposition of Qinghai spruce (Picea crassifolia) forest in China

AbstractLitter decomposition is a key ecological process as a control on nutrient cycling in forest ecosystems. Forest litter is an important carrier of element cycles in forest ecosystems. The biogeochemical cycle of elements is of great significance to plant communities and ecosystem functions. At present, most of the studies on the litter major elements have focused only on C, N, and P, and there are few studies on the biogeochemical cycle of sodium (Na) and manganese (Mn) of forest litter. In this study, we investigated the concentrations and fluxes of Na and Mn in needle litter of Qinghai spruce over a 12‐month period. We measured the release and accumulation dynamics of litter Na and Mn during litter decomposition at different canopy coverage and elevations over 3.9 years. The results show that the annual Na and Mn concentrations were 312.34 and 621.19 mg kg−1, and the annual fluxes of Na and Mn were 236.67 and 343.16 g ha−1 in needle litter, respectively. After 3.9 years of litter decomposition, Na released 15.6% and Mn accumulated 93.4% compared to the initial concentration. The concentration of Na and Mn in needle litter both accumulated fastest at low canopy coverage. The concentrations of Na and Mn were different at various elevations, but there was no obvious regularity. These results illustrate the seasonal characteristics of litter element return and nutrient cycling during litter decomposition in typical coniferous forests in the Qilian Mountains and could provide basic data and theoretical basis for ecological protection in the Qilian Mountains.

Distribution of spider mite, Tetranychus ludeni zacher on cowpea

A study was carried out during April 2022 to study the distribution pattern of spider mite, T. ludeni on cowpea plant. The study revealed that the spider mite, T. ludeniprederred top canopy leaves followed by middle and lower canopy leaves. Further, the spider mite, T. ludeni preferred lower leaf surface as compared to upper surface of the leaf.. KEYWORDS :Spider mite, Tetranychus ludeni, cowpea, distribution, plant canopy

Tree demographic drivers across temperate rain forests, after accounting for site-, species-, and stem-level attributes.

Diverse drivers such as climate, soil fertility, neighborhood competition, and functional traits all contribute to variation in tree stem demographic rates. However, these demographic drivers operate at different scales, making it difficult to compare the relative importance of each driver on tree demography. Using c. 20,000 stem records from New Zealand's temperate rain forests, we analyzed the growth, recruitment, and mortality rates of 48 tree species and determined the relative importance of demographic drivers in a multilevel modeling approach. Tree species' maximum height emerged as the one most strongly associated with all demographic rates, with a positive association with growth rate and negative associations with recruitment and mortality rates. Climate, soil properties, neighborhood competition, stem size, and other functional traits also played significant roles in shaping demographic rates. Forest structure and functional composition were linked to climate and soil, with warm, dry climates and fertile soil associated with higher growth and recruitment rates. Neighborhood competition affected demographic rates depending on stem size, with smaller stems experiencing stronger negative effects, suggesting asymmetric competition where larger trees exert greater competitive effects on smaller trees. Our study emphasizes the importance of considering multiple drivers of demographic rates to better understand forest tree dynamics.

Understanding the local endemism of Magnolia calimaensis (Lozano) Goovaerts: analysis of its genetic diversity and structure

AbstractThis study aims to comprehend the factors that influence local endemism in Magnolia calimaensis, a tree species inhabiting the rain forests of Buenaventura in Colombia, classified as critically endangered with an estimated population of fewer than 100 individuals. A total of 38 individuals were collected from the Bajo Calima and Bahía Málaga localities. Subsequently, microsatellite marker analysis of the species’ genetic diversity and structure were conducted. Nine microsatellites from other tropical Magnolia species amplified in this system, with only seven being variable and functional. The results revealed diminished levels of genetic diversity and notable indices of inbreeding for both populations (He: 0.30 / F: 0.63 for Bajo Calima and He: 0.31 / F: 0.22 for Bahía Málaga). Furthermore, F-Statistics indicate high genetic differentiation between populations (FST=0.42) and low migration (Nm=0.34). Despite the continuity of the rain forests inhabited by the species and the availability of dispersion vectors, the results suggest that its restricted distribution is not related to the landscape. We hypothesize that gene flow and broader distribution are constrained by the species’ reproductive biology. Frequent geitonogamy and self-pollination in Magnolia, along with the potential impact of Lepidoptera parasites damaging floral structures during critical developmental stages, may play a significant role. Future studies should aim to investigate these factors in detail. The genetic results emphasize the urgent need to implement genetic restoration strategies to preserve and ensure the perpetuity of known populations of M. calimaensis.

Social, Economic, and Environmental Impacts of Sentul Rain Forest Tourism Development

Sentul Rain Forest Tourism (SRFT) is one of the ecotourism objects developed in a forest area managed by Perhutani Public Company in collaboration with a private company. This study examined the social, economic, and environmental impacts of SRFT on the surrounding community before and after SRFT development. The study used quantitative descriptive analysis methods, with interviews and questionnaires. Respondents were divided into two groups: community groups receiving direct and indirect impacts. The results showed that SRFT had a positive social impact, namely increasing social accessibility, which can increase people's mobility. Economically, SRFT created jobs and increased people's income in community groups with direct and indirect impacts. Environmentally, it increased the tree covering and positively changed people's attitudes towards forest management. However, the development of SRFT also has a negative impact. Socially, increasing conflict between tourists and the community, both in the community groups receiving direct and indirect impacts. Economically, it increased the externality costs to community groups that receive direct impacts. Keywords: economy impact, ecotourism, environmental impact, rain forest, social impact

Seasonal and Spatial Dynamics of Fungal Leaf Endophytes in Eucalyptus crebra (Narrow-Leaved Ironbark)

Fungal endophytes play an important role in improving the health and productivity of native and cultivated plant species. Despite their ecological and industrial importance, few eucalypt species have been studied in terms of their endophyte communities. We examined the seasonal and spatial dynamics of fungal leaf endophytes in the model species, Eucalyptus crebra (narrow-leaved ironbark), using ITS-based amplicon sequencing. Alpha and beta diversity analyses revealed significantly higher species richness in summer compared to autumn and spring. Similarly, two-way ANOVA analysis showed significantly higher species diversity in summer compared to autumn (observed p < 0.001, Chao1 p < 0.005) and spring (observed p < 0.005, Chao1 p < 0.005). No difference in Shannon index was observed among different canopy levels across the season. Beta-diversity showed differences in fungal composition across the seasons and at various canopy levels based on unweighted UniFrac distance metric (PERMANOVA season p < 0.001, canopy p < 0.05), signifying distinct separation of fungi based on presence-absence. Ascomycota was the most abundant and diverse phylum and was present throughout the year. In contrast, Basidiomycota was only observed during cooler and drier seasons. Neofusicoccum was the most abundant genus, but distribution fluctuated significantly across the seasons. Pestalotiopsis and Neopestalotiopsis were most abundant in the low leaf canopy, whereas Pseudosydowia was most abundant in the high canopy. This study indicates that the diversity and abundance of endophytic fungi in the leaves of healthy E. crebra trees fluctuate seasonally and across canopy levels. The data generated can be used as a baseline for assessing and potentially modulating the health of E. crebra and other important Eucalyptus spp.

Modern Pollen–Vegetation Relationships: A View from the Larch Forests of Central Siberia

Understanding how pollen assemblages represent the local and regional vegetation composition is crucial for palaeoecological research. Here, we analyze 102 surface moss/soil pollen samples collected from four study regions located in various boreal forest vegetation types in Central Siberia. Despite Larix being the most prevalent tree generus in the study area, the proportion of Larix pollen can be as low as 0.6–1.5% (0.4–4.7% on average) even in localities with a high canopy density of the species. No relationship between the quantity of Larix pollen in the spectra and the abundance of Larix in the local vegetation was found. The dominant components of the pollen assemblages are Betula and Alnus fruticosa. The pollen value of Picea is low (2.6–8.2% on average), with higher proportions at sample plots where spruce is abundant in forests. Pinus is a highly prevalent pollen species within its geographical range, comprising up to 40% of pollen assemblages. Outside of the range, the ratio of Pinus pollen was higher in habitats with low canopy density and in treeless ecosystems. The composition of herbaceous pollen and spores is significantly affected by the local plant community, offering more comprehensive insights into past vegetation patterns.

Modelling marine heatwaves impact on shallow and upper mesophotic tropical coral reefs

Abstract Coral reefs ecosystems, often compared to rain forests for their high biodiversity, are threatened by ocean warming causing coral bleaching when the symbiotic relationship between dinoflagellates and corals breaks under high ocean temperatures. Thermal stress from marine heatwaves (MHWs) occur both at the surface and subsurface with subsurface MHWs lasting longer with potentially higher cumulative intensities. However, global coral bleaching models generally ignore the differences in thermal stress between surface and sea-bed levels. Here, we define MHWs at sea-bed level to model coral bleaching with daily resolution from 6 May 1993 to 31 October 2023, for 9944 tropical coral reefs between 0 and 60 m depths. We show that deeper reefs experience on average higher thermal stress and bleaching compared to surface reefs. Using surface temperature data to model bleaching for deeper corals underestimates bleaching intensities by an average of 6% ± 9% compared to the subsurface calibrated model. Our study is a starting point for more accurate coral bleaching modelling, providing additional evidence to reshape our perception of deeper coral reefs as potential refugees from climate change.

Characterization and pilot-scale downdraft gasification of invasive forestry species biomass in the Dominican Republic

In many developing countries, the primary source of energy generation is fossil fuels. However, the study and utilization of invasive forestry species for gasification can help transition away from fossil fuels and towards sustainable, renewable energy production. In the present work, we investigated the characterization and energy potential of four invasive forestry species (Prosopis juliflora, Azadirachta indica, Acacia mangium, and Calliandra calothyrsus) affecting the dry and rain forests of the Dominican Republic. We analyzed the parts (wood, bark, and branches), and transverse diameter sizes (less than 2.5 cm, 2.5–5.0 cm, and 5.0 cm) of the invasive forestry species. Additionally, we evaluated the calorific value, composition, and quality indicators of the syngas produced by these species using a downdraft gasifier. Fixed carbon, ash, and moisture content were higher in the bark compared to the wood and branches of the forestry species. Also, lower the thickness of the species branches tended to have higher moisture and ash content. A. mangium had the highest energy potential with calorific values of 20.4 MJ/kg for the biomass and 5.22 MJ/m3 for the syngas. The species P. juliflora showed a calorific value of 18.6 MJ/kg and syngas with 5.08 MJ/m3. However, the gasifier cold gas efficiency of the species P. juliflora obtained of 24.89 % which was slightly higher than A. mangium with 23.29 % based on the conversion ratio of biomass to gas. Our findings reveal the promising potential of P. juliflora, a relatively underexplored biomass, as a viable feedstock for gasification-based bioenergy production.