Tropical America Research Articles

A Review on Some Ecological Aspects of Invasive Flora Based on Comparative Analysis of “Tehri” and “Pauri” Garhwal, Uttarakhand, India

The establishment of invasive plants in a particular area leads to significant ecological changes on the native species of that area, alters ecosystem services and is one of the major drivers of biodiversity loss. In recent years, invasion by alien plants in the hilly regions has posed a severe threat to the ecosystem of these areas. A review was made in this context to study the Invasive Alien Plant Species (IAPS) of “Tehri” and “Pauri” districts. Large number of invasive alien plants was identified under different genera and families from both the study areas. Based on the growth form of invasive plants, herbs contributed the maximum percentage. Asteraceae was found to be dominating over other families followed by Solanaceae. The native range indicated differences in nativity of invasive flora found in Tehri and Pauri with a large percentage of invasive plants coming from Asia (23%) and Tropical America (26%) and respectively. It was observed that invasive plants are invading higher elevation zones which parallels with the directional filtering theory. Due to higher proliferation rates outside their native range and absence of natural predators, it is quite difficult to control this increasing expansion of invasive plants which is a call for concern and needs immediate attention. Keywords: Invasive alien plant species (IAPS), Ecosystem services, Native species, Biodiversity, Directional filtering .

A Lightweight Deep Learning Semantic Segmentation Model for Optical-Image-Based Post-Harvest Fruit Ripeness Analysis of Sugar Apples (Annona squamosa)

The sugar apple (Annona squamosa) is valued for its taste, nutritional richness, and versatility, making it suitable for fresh consumption and medicinal use with significant commercial potential. Widely found in the tropical Americas and Asia’s tropical or subtropical regions, it faces challenges in post-harvest ripeness assessment, predominantly reliant on manual inspection, leading to inefficiency and high labor costs. This paper explores the application of computer vision techniques in detecting ripeness levels of harvested sugar apples and proposes an improved deep learning model (ECD-DeepLabv3+) specifically designed for ripeness detection tasks. Firstly, the proposed model adopts a lightweight backbone (MobileNetV2), reducing complexity while maintaining performance through MobileNetV2′s unique design. Secondly, it incorporates the efficient channel attention (ECA) module to enhance focus on the input image and capture crucial feature information. Additionally, a Dense ASPP module is introduced, which enhances the model’s perceptual ability and expands the receptive field by stacking feature maps processed with different dilation rates. Lastly, the proposed model emphasizes the spatial information of sugar apples at different ripeness levels by the coordinate attention (CA) module. Model performance is validated using a self-made dataset of harvested optical images categorized into three ripeness levels. The proposed model (ECD-DeepLabv3+) achieves values of 89.95% for MIoU, 94.58% for MPA, 96.60% for PA, and 94.61% for MF1, respectively. Compared to the original DeepLabv3+, it greatly reduces the number of model parameters (Params) and floating-point operations (Flops) by 89.20% and 69.09%, respectively. Moreover, the proposed method could be directly applied to optical images obtained from the surface of the sugar apple, which provides a potential solution for the detection of post-harvest fruit ripeness.

Landscape Ecology Meets Disease Ecology in the Tropical America: Patterns, Trends, and Future Directions

Landscape Ecology Meets Disease Ecology in the Tropical America: Patterns, Trends, and Future Directions

Traditional uses, phytochemistry, pharmacological significance and toxicology of Argemone mexicana L. – A review approach

Argemone Mexicana L. (AM, Papaveraceae) is found and native to tropical America. Many cultures have traditionally used this annual herb to treat a variety of ailments, including skin disorders, digestive problems, eye issues, and anti-dotes. Argemone Mexicana (AM), a plant with a long history of traditional use, has recently gained renewed attention from researchers due to its potential pharmacological benefits. The possibility that this plant could be used to develop new therapies has inspired further research. Information about AM was collected from scientific databases published between January 2000 and March 2022. These databases include Elsevier, PubMed, Web of Science, NOPR, Google Scholar, ResearchGate, Wiley, SpringerLink, and ACS publications. Numerous chemical constituents present in AM have been found to have medicinal properties, such as alkaloids, flavonoids, tannins, phenolic compounds, saponin, terpenoids, and cardiac glycosides. Various parts of the AM plant exhibit antimicrobial, wound healing, antioxidant, antimalarial, larvicidal, anthelmintic, antidiabetic, hepatoprotective, anticancer effects, and have been used to treat sexually transmitted diseases. However, the plant is also known to be toxic, and its use can lead to a number of adverse effects, including dermatitis, gastrointestinal disturbances, and neurological damage. This review critically evaluates recent developments in the traditional use, phytochemistry, pharmacology, and toxicology of AM in order to provide a scientific basis for reasonable utilization and further research.

Spatial–temporal trends in leprosy burden and its associations with socioeconomic and physical geographic factors: results from the Global Burden of Disease Study 2019

ObjectivesThe purpose of our study was to assess the multiscalar changes in leprosy burden and its associated risk factors over the last three decades. Study designWe conducted an in-depth examination of leprosy's spatial–temporal trends at multiple geographical scale (global, regional, and national), utilizing information from Global Burden of Disease, Injuries, and Risk Factors Study (GBD 2019). MethodsIncidence and the estimated annual percentage change (EAPC) in age-standardized incidence rate (ASIR) of leprosy were determined, with countries categorized based on leprosy incidence changes. We examined socioeconomic and physical geography influences on leprosy incidence via Spearman correlation analysis, using ternary phase diagrams to reveal the synergetic effects on leprosy occurrence. ResultsGlobally, incident cases of leprosy decreased by 27.86% from 1990 to 2019, with a reduction in ASIR (EAPC = −2.53), yet trends were not homogeneous across regions. ASIR and EAPC correlated positively with sociodemographic index (SDI), and an ASIR growth appeared in high SDI region (EAPC = 3.07). Leprosy burden was chiefly distributed in Tropical Latin America, Oceania, Central Sub-Saharan Africa, and South Asia. Negative correlations were detected between the incidence of leprosy and factors of SDI, GDP per capita, urban population to total population, and precipitation, whereas the number of refugee population, temperature, and elevation showed opposite positive results. ConclusionsDespite a global decline in leprosy over the past three decades, the disparities of disease occurrence at regional and national scales still persisted. Socioeconomic and physical geographic factors posed an obvious influence on the transmission risk of leprosy. The persistence and regional fluctuations of leprosy incidence necessitate the ongoing dynamic and multilayered control strategies worldwide in combating this ancient disease.

The Neogene record of the dinoflagellate cyst genus Trinovantedinium Reid 1977 in the tropical Americas

The genus Trinovantedinium Reid 1977 comprises eleven NeogeneQuaternary and one Paleogene dinoflagellate cyst taxa that have been successfully used for biostratigraphy. Combining new and published records of Trinovantedinium species in the Neogene of the tropical Americas, we report preliminary stratigraphic ranges for T. applanatum (AquitanianRecent), T. ferugnomatum (BurdigalianZanclean), T. glorianum (BurdigalianMessinian), T. papula (AquitanianZanclean), T. uitpensis (AquitanianTortonian), T. variabile (AquitanianRecent) and T.? xylochoporum (AquitanianMessinian) in the region. Although the stratigraphic ranges of T. applanatum, T. variabile and T.? xylochoporum in the tropical Americas seem to be coetaneous with previous records elsewhere, the first appearance datums of T. ferugnomatum, T. glorianum and T. papula seem to be at least ∼2–3 Myr. older in the tropical Americas. In contrast, only the last appearance datum of T. glorianum seems to be ∼4 Myr. younger in the Northern Hemisphere. Our results demonstrate that the Cenozoic marine palynological record of the tropical Americas is therefore key to discriminate dinoflagellate cyst stratigraphic ranges across latitudes.

Taxonomic delimitation in Aspidosperma sect. Pungentia (Apocynaceae) based on morphological and leaf anatomical traits

Aspidosperma is one of the most representative genera in Apocynaceae in Brazil, composed of trees or small trees popularly known as perobas. The genus is distributed throughout tropical America, from Mexico to Argentina, with the exception of Chile. It comprises 80 species, 42 of which occur in Brazil, which is the center of diversity for the genus. Aspidosperma triternatum and Aspidosperma quebracho-blanco, name the Aspidosperma sect. Pungentia, section is easily distinguished from the others, even in the vegetative state, by grouping species that have leaves with pungent apexes, unique in the genus. However, A. triternatum and A. quebracho-blanco are difficult to distinguish due to the morphological similarities they present, such as the pungent apex of their whorled leaves and the yellowish white color of their flowers. Therefore, our objective was to develop a study to obtain leaf morphological using the usual methods of microscopy. The most important diagnostic characters useful for delimiting the species were: the number of pairs of secondary veins; the patterns of distance between these and the median and distal region, as well as the reticulation of these veins; the branching of the tertiary veins; the impression of the quaternary veins as well as their development and the shape of the areola; shape of epidermal cells; cuticular ornamentation pattern; types and distribution of trichomes; distribution of stomata; organization and number of cell layers in mesophyll. We have shown from the performed study that the species have remarkable morphological and anatomical differences which made possible a better circumscription of the group.

Contributions of human cultures to biodiversity and ecosystem conservation.

The expansion of globalized industrial societies is causing global warming, ecosystem degradation, and species and language extinctions worldwide. Mainstream conservation efforts still focus on nature protection strategies to revert this crisis, often overlooking the essential roles of Indigenous Peoples and Local Communities (IP&LC) in protecting biodiversity and ecosystems globally. Here we assess the scientific literature to identify relationships between biodiversity (including ecosystem diversity) and cultural diversity, and investigate how these connections may affect conservation outcomes in tropical lowland South America. Our assessment reveals a network of interactions and feedbacks between biodiversity and diverse IP&LC, suggesting interconnectedness and interdependencies from which multiple benefits to nature and societies emerge. We illustrate our findings with five case studies of successful conservation models, described as consolidated or promising 'social-ecological hope spots', that show how engagement with IP&LC of various cultures may be the best hope for biodiversity and ecosystem conservation, particularly when aligned with science and technology. In light of these five inspiring cases, we argue that conservation science and policies need to recognize that protecting and promoting both biological and cultural diversities can provide additional co-benefits and solutions to maintain ecosystems resilient in the face of global changes.

Otoliths of the Gobiidae from the Neogene of tropical America

Otoliths are common and diverse in the Neogene of tropical America. Following previous studies of Neogene tropical American otoliths of the lanternfishes (Myctophidae), marine catfishes (Ariidae), croakers (Sciaenidae), and cusk-eels (Ophidiiformes), we describe here the otoliths of the gobies (Gobiidae). The Gobiidae represent the richest marine fish family, with more than 2000 species worldwide and about 250 in America. In the fossil record too they are the species richest family in the Neogene of tropical America. We have investigated otoliths sampled from Ecuador, Pacific and Atlantic Panama, Atlantic Costa Rica, Dominican Republic, Venezuela, and Trinidad, ranging in age from late Early Miocene (late Burdigalian) to late Early Pleistocene (Calabrian). Most of the studied material originates from the collection expeditions of the Panama Paleontology Project (PPP). Our study represents the first comprehensive record of fossil gobies from America, and we recognize 107 species, of which 51 are new to science, 35 are in open nomenclature, and 19 represent species that also live in the region today. Previously, only two fossil otolith-based goby species have been described from the Neogene of tropical America. The dominant gobies in the fossil record of the region are from the Gobiosomatini, particularly of genera living over soft bottoms or in deeper water such as Bollmannia, Microgobius, Antilligobius, and Palatogobius. Another purpose of our study is to provide a first comprehensive account of otoliths of the extant Gobiidae of America, which we consider necessary for an adequate identification and interpretation of the Neogene otoliths. We studied otoliths of 130 extant American gobiid species and figured 106 of them for comparison. We also present a morphological analysis and characterization of the extant otoliths as a basis for the identification of fossil otoliths. Problems that commonly arise with the identification of fossil otoliths and specifically of fossil goby otoliths are addressed and discussed. A comparison of the history of the Gobiidae in tropical America reveals a high percentage of shared species between the Pacific and the Atlantic basins during the Late Miocene (Tortonian and Messinian) from at least 11 to 6 Ma. A recording gap on the Pacific side across the Pliocene allows a comparison again only in the late Early Pleistocene (Calabrian, 1.8 to 0.78 Ma), which shows a complete lack of shared species. These observations support the effective closure of the former Central American Seaway and emersion of the Isthmus of Panama in the intervening time. Groups that today only exist in the East Pacific were also identified in the Miocene and Pliocene of the West Atlantic, and there is also at least one instance of a genus now restricted to the West Atlantic having occurred in the East Pacific as late as the Pleistocene. The evolution of gobies in tropical America and the implications thereof are extensively discussed. Furthermore, observations of fossil gobies in the region are discussed in respect to paleoenvironmental indications and paleobiogeographic aspects.

Phylogenetic evidence reshapes the taxonomy of Cacao and its allies (Theobroma and Herrania; Malvaceae, Byttnerioideae)

Theobroma (Malvaceae, Byttnerioideae), the cacao genus, has a taxonomic history spanning over two centuries. Currently, it comprises 23 species of trees from lowland forests from the Tropical Americas. Herrania, a closely related genus described later, includes 17 additional species commonly referred to as “wild cacaos.” Phylogenetic relationships and morphological circumscriptions between Theobroma and Herrania have been the subject of debate. While Herrania has traditionally been treated as a separate genus based on evident morphological differences in leaf and petal features, it shares similarities with Theobroma in terms of habit, inflorescence, and fruit types. Recent phylogenetic evidence, incorporating a broader taxonomic sampling and a total-evidence analysis, suggested that Theobroma is paraphyletic, with Herrania nested within it. This finding supports the restoration of a classical circumscription of Theobroma wherein Herrania is considered a section of the former genus. Here, we provide a detailed account of the taxonomic history at infrageneric levels and propose one new subsection, two names at new ranks (to better allocate the diversity within T. sect. Herrania), and nine new combinations encompassing this expanded circumscription of Theobroma. In our study, we delimit Theobroma with forty species divided into six sections: T. sect. Glossopetalum (14 spp.), T. sect. Herrania (17 spp.), T. sect. Oreanthes (5 spp.), T. sect. Rhytidocarpus (1 sp.), T. sect. Telmatocarpus (2 spp.), and T. sect. Theobroma (1 sp.). Furthermore, we recognize three subsections within T. sect. Herrania. Alongside these newly proposed changes, we present a section-level identification key and provide diagnostic characters for each taxon.

Global epidemiology of cannabis use disorders and its trend from 1990 to 2019: Benchmarking analysis of the global burden of disease study.

Cannabis is one of the most widely used psychoactive substances globally, with an increasing trend in its legalization for both medical and recreational purposes in various countries. While cannabis offers potential therapeutic benefits, its regular use can lead to the development of Cannabis Use Disorders (CUDs). Understanding the epidemiology of CUDs is crucial in assessing the public health burden associated with cannabis use. Epidemiological parameters of CUDs were assessed using the Global Burden of Disease (GBD) methodology across different age-groups, years, sexes, and locations worldwide from 1990-2019. Globally, for both sexes combined, prevalent cases of CUDs increased steadily from 17.1 million(95%UI=12.7-22.8million) in 1990 to 23.8-million(95%UI=17.8-30.9 million) in 2019. All age-adjusted highest number of incidence observed in High-Income-North-America(HINA)(121/100,000), followed by Australasia(100/100,000), Oceania(83.97/100,000), Tropical Latin America(69.59/100,000). Globally, age-standardized disability-adjusted life years rate(ASDR) observed higher in HINA, followed by Australasia, and Western-Europe. In male, all-age incidence counts increased from 1.7 million(95%UI=1.3-2.4million) in 1990 to 2.4 million(95%UI=1.8-3.2 million) in 2019. The highest annual percentage of change in age-standardized incidence rate(ASIR) was found in East-Asia (22%) followed by Middle-East and North-Africa(MENA)(15%). The age group of 15-24 years exhibited the highest burden of CUDs. The widespread occurrence of CUDs on a global scale poses a substantial challenge to public health. Understanding the impact of CUDs and implementing evidence-based interventions is crucial in mitigating the associated individual, societal, and economic burdens. Continued research, collaboration, and knowledge dissemination are essential to inform policies, prevention efforts, and treatment strategies aimed at addressing CUDs on a global-scale.

Eryngium foetidum Reported as a New Host of Meloidogyne enterolobii in the State of Pará, in the Eastern Amazon Region, Brazil

Amazon chicory (Eryngium foetidum L. [Apiaceae]), also known as culantro, is native to Tropical America and the West Indies. It belongs to the unconventional food plants (UFPs) group, and in addition to be consumed as a spice herb, it possesses a wide range of ethnomedicinal uses (Paul et al. 2011). In 2019, in the eastern Amazon region of Brazil, state of Pará, producers of E. foetidum in the municipality of Castanhal (01°15'363” S 047°10'232” W) reported the occurrence of underdeveloped plants with leaf yellowing and a large number of galls in the root system, which are typical symptoms of root-knotting nematode. Soil and root samples were collected and sent to the Nematology Laboratory (LabNema) located at the Faculty of Agrarian and Veterinary Sciences, UNESP, Jaboticabal, São Paulo, Brazil. A total of 46 second-stage juveniles (J2s) were extracted per 100 cm3 of soil, and a total of 460 eggs and J2s Meloidogyne spp. were found per gram of root. Morphological and molecular techniques were used to identify the species. The analysis of the perineal patter of ten females revealed thin striations in an oval shape with a high and semi-trapezoidal dorsal arch. No striations were observed in the perivulvar region. The labial region of the ten males analyzed exhibited a non-prominent labial disc, fused and slightly recessed submedian lips, with no apparent annulations. The morphological characteristics observed in the adults were consistent with those originally described for Meloidogyne enterolobii (Yang; Eisenback, 1983), confirming the species purity of the recovered population. Three individual nematodes had their 18S rDNA region sequenced (Holterman et al. 2006) which showed an average identity of 99.7% with other sequences of M. enterolobii available in the GenBank database. A Bayesian phylogenetic tree was constructed, providing insights into the specific relationship of M. enterolobii recovered from E. foetidum with other related nematodes. Each of the three sequenced nematodes represented a unique haplotype, resulting in their separation into distinct clades. Moreover, the obtained sequences presented polymorphisms that differed from the M. enterolobii sequences already available in the database, highlighting the genetic diversity of this species in relation to its original host (Silva et al. 2021). The species M. enterolobii was also confirmed using species-specific primers for M. incognita, M. javanica, and M. enterolobii (Zijlstra et al. 2000; Tigano et al. 2010). To confirm the pathogenicity of M. enterolobii on E. foetidum, a modified Koch Postulate was conducted. Six seedlings of E. foetidum were transplanted individually to 10-liter pots containing autoclaved soil. Each pot was then inoculated with 5 mL of a suspension containing 3,000 eggs and J2s from the original population of M. enterolobii obtained from E. foetidum. After 90 days, the inoculated plants exhibited root galls with a plentiful egg mass, in contrast to the healthy non-inoculated plants. The average number of M. enterolobii nematodes recovered from the roots of the inoculated plants was 42,040 eggs and J2s, resulting in a reproduction factor (RF) of 14.0. The importance of reporting the occurrence of M. enterolobii in E. foetidum is due to the fact that this plant species is cultivated in a crop rotation system with other vegetables such as lettuce and coriander, which are also hosts of M. enterolobii. Consequently, different crop rotation strategies and control alternatives need to be considered in areas where E. foetidum is grown. This is the first report of E. foetidum serving as a host for the root-knot nematode M. enterolobii worldwide.

The Invasive Weed Trianthema portulacastrum in Israel.

Trianthema portulacastrum L. (Aizoaceae), commonly known as desert horse purslane or black pigweed, is a C4 dicot succulent annual herb that is widespread in Southeast Asia, tropical America, Africa, and Australia. In Israel, it is an invasive weed of increasing importance in agricultural fields. The aim of this study was to investigate the biology of this invasive weed and its spread in the Hula Valley of Israel. Initial studies included the investigation of the T. portulacastrum specimens held at the Israel National Herbarium. On-site surveillance for the identification of weed infestation locations was conducted in the Hula Valley throughout 2019-2022, and an infestation map was assembled. In a study of the plant biology, greenhouse pot experiments revealed that T. portulacastrum seeds emerge best from the upper soil levels, and as seed depth increases, the emergence rate decreases, so that at 6 cm soil depth, there was no emergence. In controlled-environment growth chamber studies, there were no significant differences in germination with or without light. A maximum germination of 81% was observed for a 12 h night/day of 25/35 °C regime. Germination rates decreased with the decrease in temperature. A seed germination thermal time model that was developed for estimating the minimum temperature required for germination (Tbase) computed this temperature to be 10 °C. This study revealed the biology, in particular seed germination and emergence requirements, of the invasive weed T. portulacastrum that has spread in the Hula Valley in Israel and beyond. Future research will focus on an examination of control measures to combat this invasive weed.

Human influence on the distribution of cacao: insights from remote sensing and biogeography

Cacao (Theobroma cacao, Malvaceae) is an important tree crop in Africa and in the Americas. Current genomic evidence suggests that its original range in Tropical Americas was smaller than its current distribution and that human-mediated dispersal occurred before European colonization. This includes regions like Mesoamerica and Eastern Amazonia where cacao is supposedly naturally occurring. In this study, we utilize remote sensing and land use data to examine the influence of human activities on cacao-growing regions and explore patterns between cacao distribution and anthropized areas. By evaluating nearly nine thousand preserved specimen collections, we worked with a comprehensive occurrence dataset that considers taxonomy and distribution. We then analyzed remote sensing images of specimen locations and compared land use profiles of regions into which cacao was introduced with documented native areas. Our findings revealed a clear association between anthropized areas and cacao specimens, with the majority located in areas strongly affected by human activities. Conversely, regions closer to the proposed native range of cacao exhibit less human impact. These results, while accounting for sampling bias, reinforce the idea that humans may have played a significant role in cacao’s dispersal, even in parts of the Amazon where its native status remains uncertain. The discussion on cacao’s native range and identification of introduced areas hold implications for jurisdiction, access to genetic resources, and conservation efforts. Additionally, it is relevant to debates surrounding the repatriation of genetic data of economically important crops. Understanding the historical human influence on cacao’s distribution is crucial for addressing issues of crop improvement, conservation, and sustainable use.

Status and prospects of Avocado cultivation in India

Avocado (Persia americana) is a native to tropical America. It was originated in Mexico and Central America, possibly from more than one wild species. The early Spanish explorers recorded its cultivation from Mexico to Peru. Avocado production increased almost 1100 percent as compared to 1961. In India, Avocado was introduced in Bangalore and hill stations like Kallar near Nilgris, Palani hills of Kodaikanal, Shrevaroy hills of Yercaud, Coorg during 1912 and 1940. Later the seedlings of those varieties spread over humid subtropical region but remain neglected. The avocado cultivation have gained an overwhelming popularity during last one decade due to nutritional properties of the fruits. Presently around 7000 tones of avocados annually and the production is increasing rapidly as more and more areas is being brought under cultivation. The agro- climatic conditions prevailing in various parts of the country appear to be favorable for bringing more areas under avocado. Recently several varieties belonging to all three horticultural races i.e., West Indian, Guatemalan and Mexican have been introduced in India. Some varieties such as Arka Supreme, Arka Ravi and TKD-1 were released by CHES(IIHR), Chettalli (Coorg) and HRS station Thayangudusai (TN). These research centres are maintaining large number of accession of avocado germplasm. CHES (IIHR), Chettalli standardized the cleft grafting method for multiplication of avocado. Avocado is planted at a distance of 5 to 8 meters depending on the vigour of variety and growth habit. In general, young avocado trees are given N, P2O5 and K2O in the proportion of 1:1:1 and older trees in the proportion of 2:1:2 . Both A & B types are planted in the orchards for proper pollination and sufficient number of pollinators should be encouraged by keeping honey bee boxes. The studies conducted at CHES, Chettalli revealed that Apis cerena was the major pollinator followed by Apis florea, Tetragonula sp. and ants. Avocado plants seedlings start bearing five to six years after planting while grafted plants start yielding in 3-4 years. Harvesting is done manually and bruising and exposing fruits to direct sunlight is avoided. The yield ranges from 100 to 500 fruits per tree. The peak harvest time is different in different region. Presently, there is very little organized marketing system for avocado in India as the production is small and production areas are scattered. Avocados are mostly produced in Coorg, Chikmagalur, Shivamogga, Kodaikanal, Lower Palani hills, Kallar and Wayanad. The demand of avocado is manly in metro cities like Chennai, Bengaluru, Mumbai, Delhi,Pune and Ahmadabad. A large quality of avocado and avocado products are being imported in the country to fulfil the demand. Avocado is mainly used fresh, in sandwich filling or in salads.. Several products of avocado i.e. Arka avocado chutney, Arka avocado bread spread, Spray dried avocado powder have been developed by ICAR-IIHR, Bangalore. The cultivation area is rapidly growing in Maharashtra, Karnataka, Tamil Nadu, North Eastern States etc. of the country. The seminars, workshops, field days, awareness programmes, demonstrations etc. conducted by ICAR-IIHR, Bangalore during last one decade played a vital role in popularization of avocado in the country. Visualizing the demand and rising popularity of avocado at domestic and international level, there is good scope of Avocado cultivation in India. There is need to provide suitable technological backup to fulfil the requirement of growers, processing industry and consumers

Climatology of icing conditions over Colombia based onERA5reanalysis and in situ observations

AbstractThis study shows vertical profiles and spatial distribution of upper‐air icing frequency over the tropical Americas. We estimated the in‐flight icing (IFI) over Colombia using the Current Icing Product‐sonde‐A algorithm over two data sets: (1) vertical soundings of temperature and relative humidity and surface station data taken at 12 Coordinated Universal Time or UTC (07 Local Time or LT) on five sites and (2) ERA5 at 00, 06, 12 and 18 UTC (19, 01, 07 and 13 LT). In either case, icing was defined for IFI values exceeding 0.01. Results show that icing tends to occur between 550 and 300 hPa (4.5 and 8.6 km altitude), with a maximum at 500–550 hPa and monotonically decreasing to zero until reaching 300 hPa. Aeronautic reports were used to evaluate the total column IFI and a layer‐based IFI detection with a probability of detection of 87% and 71%, respectively. The annual cycle of IFI is modulated by the meridional migration of the Intertropical Convergence Zone (ITCZ) with a bimodal distribution with peaks during the rainiest seasons. Spatially, IFI hotspots are found in the Pacific, the Andes Mountains and the Amazonia regions of Colombia; the northern Colombia Caribbean region show lower IFI frequency with a relative maximum collocated over the Sierra Nevada de Santa Marta mountains. The IFI exhibits a strong diurnal cycle with a high between night‐time to early morning and a low around noon.

The Invasive Mechanisms of the Noxious Alien Plant Species Bidens pilosa

Bidens pilosa L. is native to tropical America and has widely naturized from tropical to warm temperate regions in Europe, Africa, Asia, Australia, and North and South America. The species has infested a wide range of habitats such as grasslands, forests, wetlands, streamlines, coastal areas, pasture, plantations, agricultural fields, roadsides, and railway sides and has become a noxious invasive weed species. B. pilosa forms thick monospecific stands, quickly expands, and threatens the indigenous plant species and crop production. It is also involved in pathogen transmission as a vector. The species was reported to have (1) a high growth ability, producing several generations in a year; (2) a high achene production rate; (3) different biotypes of cypselae, differently germinating given the time and condition; (4) a high adaptative ability to various environmental conditions; (5) an ability to alter the microbial community, including mutualism with arbuscular mycorrhizal fungi; and (6) defense functions against natural enemies and allelopathy. The species produces several potential allelochemicals such as palmitic acid, p-coumaric acid, caffeic acid, ferulic acid, p-hydroxybenzoic acid, vanillic acid, salycilic acid, quercetin, α-pinene, and limonene and compounds involved in the defense functions such as 1-phenylhepta-1,3,5-trine, 5-phenyl-2-(1-propynyl)-thiophene, 5-actoxy-2-phenylethinyl-thiophene, and icthyothereol acetate. These characteristics of B. pilosa may contribute to the naturalization and invasiveness of the species in the introduced ranges. This is the first review article focusing on the invasive mechanisms of the species.

Closure of tropical seaways favors the climate and vegetation in tropical Africa and South America approaching their present conditions

The tectonically induced closure/constriction of the Central American Seaway (CAS) and Indonesian Seaway (Indo) during the early to mid-Pliocene has been associated with many climatic events, such as the onset of Northern Hemisphere glaciation, the intensification of the Atlantic meridional overturning circulation (AMOC) and Australian aridification. However, studies on how the closure/constriction of tropical seaways affects the tropical climate system are still sparse and not systematic. Previous studies have linked the constriction of Indo to the aridification over East Africa and discussed the role of CAS closure in affecting the moisture supply over South America, but the underlying mechanism and combined effect of both tropical seaways are not well studied. In this study, we evaluate the impacts of tropical seaways' closure/constriction and distinguish the relative roles of CAS and Indo on climate in tropical Africa and South America using the NorESM-L Atmosphere-Ocean General Circulation Model (AOGCM) and a dynamic vegetation model (LPJ-GUESS). Our results show that the closure of the CAS leads mainly to aridification in northeastern Brazil, resulting in an expansion of tropical xerophytic shrubland and savanna in this region. The narrowing of the Indo mainly leads to enhanced aridification in eastern tropical Africa, and reduces the extent of tropical forests in eastern and northern tropical Africa, which is generally consistent with the data. The closure/narrowing of the two tropical seaways results in a superposition of the individual seaway's effect, particularly over northeastern Brazil region, which exhibits enhanced aridification compared to the closure of the individual CAS. The seaways' changes are shown to be pivotal for the evolution of climate and vegetation over East Africa and northeastern South America to contemporary conditions.

Selective logging intensity and time since logging drive tropical bird and dung beetle diversity: a case study from Amazonia

SummaryUnderstanding how selective logging affects biodiversity is crucial to planning cost-effective conservation strategies in tropical forests, yet there is limited understanding of its impacts on fauna functional diversity in the tropical Americas. We assessed how selective logging intensification and time since logging influence multiple metrics of fauna functional integrity in the Brazilian Amazon by collecting bird and dung beetle data within 48 logging management units that had experienced varying exploitation intensities between 1.5–2.0 and 5.0–6.0 years before the faunal surveys. We investigated assemblage responses and used functional attributes to assess changes in functional diversity, specialization, originality and species rarity. Using point counts and pitfall traps, we collected 5081 records of 182 bird species and 7892 dung beetles from 45 species. Logging intensification led to significant declines in most dung beetle responses and bird body mass, whereas time since logging was a key driver of dung beetle and bird functional and taxonomic diversity. Our study presents novel empirical evidence of how logging intensification effects vary across taxa, ecological metrics and time since logging, which is key to informing forest conservation and further investigating environmental degradation impacts on tropical biodiversity.

Polypore funga and species diversity in tropical forest ecosystems of Africa, America and Asia, and a comparison with temperate and boreal regions of the Northern Hemisphere

Polypores play a crucial role in energy recycling and forest regeneration in forest ecosystems. The majority of them are wood degraders; some are forest pathogens and others are ectomycorrhizal symbionts. The basidiocarps provide food and shelter for many organisms, mostly invertebrates, but also some vertebrates, as well as food and medicine for humans. Despite extensive research on the species diversity and phylogenetic relationships of polypores in recent years, there remains a lack of comprehensive understanding of their distribution patterns and species composition at the large scale. Checklists of polypores from the tropical zone, including tropical Africa, tropical America, and tropical Asia, were analyzed for species diversity, distribution patterns, major taxa, and nutritional modes. A total of 1,902 polypore species was found in the three regions, representing 8 orders, 46 families, and 250 genera of Agaricomycetes. The orders Polyporales (especially the family Polyporaceae) and Hymenochaetales (especially the family Hymenochaetaceae) had the most prolific taxa, with their species accounting for 93.4% of the total polypores listed. Each of 1,565 (or 82.3%) of the total 1,902 species were found in only one of the three regions studied, and we treat them temporarily as “regional endemic species”. Only 141 species were shared among all three regions, accounting for a mere 7.4%. Tropical Africa and tropical America had the greatest number of shared species and the highest Sørensen similarity index (SC) value. Tropical forests had a higher species richness compared with temperate to boreal forests of the Northern Hemisphere, and in addition, also a higher proportion of white rot polypores compared to brown rot and ectomycorrhizal species. This study outlines the distribution patterns and species diversity of polypores in the world, shedding light on their ecological significance in diverse ecosystems.