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2.
Int J Biometeorol ; 67(5): 913-925, 2023 May.
Artigo em Inglês | MEDLINE | ID: mdl-37010574

RESUMO

Climate change has significantly impacted vegetation phenology across the globe with vegetation experiencing an advance in the spring green-up phases and a delay in fall senescence. However, some studies from high latitudes and high elevations have instead shown delayed spring phenology, owing to a lack of chilling fulfillment and altered snow cover and photoperiods. Here we use the MODIS satellite-derived view-angle corrected surface reflectance data (MCD43A4) to document the four phenological phases in the high elevations of the Sikkim Himalaya and compared the phenological trends between below-treeline zones and above-treeline zones. This analysis of remotely sensed data for the study period (2001-2017) reveals considerable shifts in the phenology of the Sikkim Himalaya. Advances in the spring start of the season phase (SOS) were more pronounced than delays in the dates for maturity (MAT), senescence (EOS), and advanced dormancy (DOR). The SOS significantly advanced by 21.3 days while the MAT and EOS were delayed by 15.7 days and 6.5 days respectively over the 17-year study period. The DOR showed an advance of 8.2 days over the study period. The region below the treeline showed more pronounced shifts in phenology with respect to an advanced SOS and a delayed EOS and DOR that above treeline. The MAT, however, showed a greater delay in the zone above the treeline than below. Lastly, unlike other studies from high elevations, there is no indication that winter chilling requirements are driving the spring phenology in this region. We discuss four possible explanations for why vegetation phenology in the high elevations of the Eastern Himalaya may exhibit trends independent of chilling requirements and soil moisture due to mediation by snow cover.


Assuntos
Mudança Climática , Neve , Estações do Ano , Temperatura
3.
Proc Biol Sci ; 289(1973): 20212650, 2022 04 27.
Artigo em Inglês | MEDLINE | ID: mdl-35473372

RESUMO

The collection of caterpillar fungus accounts for 50-70% of the household income of thousands of Himalayan communities and has an estimated market value of $5-11 billion across Asia. However, Himalayan collectors are at multiple economic disadvantages compared with collectors on the Tibetan Plateau because their product is not legally recognized. Using a customized hybrid-enrichment probe set and market-grade caterpillar fungus (with samples up to 30 years old) from 94 production zones across Asia, we uncovered clear geography-based signatures of historical dispersal and significant isolation-by-distance among caterpillar fungus hosts. This high-throughput approach can readily distinguish samples from major production zones with definitive geographical resolution, especially for samples from the Himalayan region that form monophyletic clades in our analysis. Based on these results, we propose a two-step procedure to help local communities authenticate their produce and improve this multi-national trade-route without creating opportunities for illegal exports and other forms of economic exploitation. We argue that policymakers and conservation practitioners must encourage the fair trade of caterpillar fungus in addition to sustainable harvesting to support a trans-boundary conservation effort that is much needed for this natural commodity in the Himalayan region.


Assuntos
Fungos , Ásia , Geografia
5.
Ann Bot ; 123(1): 181-190, 2019 01 01.
Artigo em Inglês | MEDLINE | ID: mdl-30165602

RESUMO

Background and Aims: Kin selection theory predicts that a parent may minimize deleterious effects of competition among seeds developing within ovaries by increasing the genetic relatedness of seeds within an ovary. Alternatively, the number of developing seeds could be reduced to one or a few. It has also been suggested that single or few seeded fruits may be correlated with small flowers, and multi-ovulate ovaries or many seeded fruits may be associated with large flowers with specialized pollination mechanisms. We examined the correlation between flower size and seed number in 69 families of monocotyledons to assess if correlations are significant and independent of phylogeny. Methods: We first examined the effect of phylogenetic history on the evolution of these two traits, flower size and seed number, and then mapped correlations between them on the latest phylogenetic tree of monocotyledons. Results: The results provide phylogenetically robust evidence of strong correlated evolution between flower size and seed number and show that correlated evolution of traits is not constrained by phylogenetic history of taxa. Moreover, the two character combinations, small flowers and a single or few seeds per fruit, and large flowers and many seeded fruits, have persisted in monocotyledons longer than other trait combinations. Conclusions: The analyses support the suggestion that most angiosperms may fall into two categories, one with large flowers and many seeded fruits and the other with small flowers and single or few seeded fruits, and kin selection within ovaries may explain the observed patterns.


Assuntos
Evolução Biológica , Flores/anatomia & histologia , Magnoliopsida/anatomia & histologia , Magnoliopsida/fisiologia , Sementes/fisiologia , Flores/crescimento & desenvolvimento , Magnoliopsida/crescimento & desenvolvimento , Filogenia
8.
Proc Biol Sci ; 283(1842)2016 11 16.
Artigo em Inglês | MEDLINE | ID: mdl-27852800

RESUMO

Competition among developing seeds and sibling rivalry within multiovulated ovaries can be deleterious for both the maternal parent and the siblings. Increased genetic relatedness of seeds within the ovary may foster kin selection and reduce the deleterious consequences of sibling competition. The pollen parent may also be selected for siring all progeny within a fruit. I propose a series of hypotheses to explain the evolution of a number of reproductive traits in angiosperms in the context of kin selection and sibling rivalry within the ovaries of angiosperms. I present evidence to show that a single-pollen parent, indeed, often sires seeds within multiovulated ovaries. Various types of pollen aggregations and transfer of such pollen masses to the stigmas of flowers by specialized pollinators make this increased genetic relatedness possible. An alternative mode to reduce sibling rivalry may be the reduction of ovule number to one, an evolutionary trend that has independently occurred many times in flowering plants. Finally, I build on previously established correlations to predict two sets of correlations among reproductive traits. In the first case, large showy flowers, transfer of pollen en masse by specialized pollinators, and multiovulated ovaries and multisided fruits seem to be correlated. In the second case, the previously established correlations among small and inconspicuous flowers, pollination by wind, water or generalist insects, flowers and fruits with few or single ovules and seeds, respectively, may also include monoecy or dioecy. Although correlations among many of these traits have been established in the past, I invoke kin selection and sibling competition to explain the evolution of correlated traits as two distinct evolutionary pathways in angiosperms.


Assuntos
Evolução Biológica , Fenômenos Fisiológicos Vegetais , Plantas/genética , Polinização , Sementes/genética , Flores/genética , Fenótipo , Pólen/genética , Reprodução
9.
10.
Ambio ; 51(6): 1474-1484, 2022 Jun.
Artigo em Inglês | MEDLINE | ID: mdl-34962639

RESUMO

As the two largest countries by population, China and India have pervasive effects on the ecosphere. Because of their human population size and long international boundary, they share biodiversity and the threats to it, as well as crops, pests and diseases. We ranked the two countries on a variety of environmental challenges and solutions, illustrating quantitatively their environmental footprint and the parallels between them regarding the threats to their human populations and biodiversity. Yet we show that China and India continue to have few co-authorships in environmental publications, even as their major funding for scientific research has expanded. An agenda for collaboration between China and India can start with the shared Himalaya, linking the countries' scientists and institutions. A broader agenda can then be framed around environmental challenges that have regional patterns. Coordinated and collaborative research has the potential to improve the two countries' environmental performance, with implications for global sustainability.


Assuntos
Ciência Ambiental , Biodiversidade , China , Humanos , Índia
11.
Biol Lett ; 7(5): 767-70, 2011 Oct 23.
Artigo em Inglês | MEDLINE | ID: mdl-21525050

RESUMO

The Himalayas are assumed to be undergoing rapid climate change, with serious environmental, social and economic consequences for more than two billion people. However, data on the extent of climate change or its impact on the region are meagre. Based on local knowledge, we report perceived changes in climate and consequences of such changes for biodiversity and agriculture. Our analyses are based on 250 household interviews administered in 18 villages, and focused group discussions conducted in 10 additional villages in Darjeeling Hills, West Bengal, India and Ilam district of Nepal. There is a widespread feeling that weather is getting warmer, the water sources are drying up, the onset of summer and monsoon has advanced during last 10 years and there is less snow on mountains than before. Local perceptions of the impact of climate change on biodiversity included early budburst and flowering, new agricultural pests and weeds and appearance of mosquitoes. People at high altitudes appear more sensitive to climate change than those at low altitudes. Most local perceptions conform to scientific data. Local knowledge can be rapidly and efficiently gathered using systematic tools. Such knowledge can allow scientists to test specific hypotheses, and policy makers to design mitigation and adaptation strategies for climate change, especially in an extraordinarily important part of our world that is experiencing considerable change.


Assuntos
Mudança Climática , Altitude , Índia , Nepal
13.
Science ; 374(6563): 42, 2021 Oct.
Artigo em Inglês | MEDLINE | ID: mdl-34591634

RESUMO

A history of tropical ecosystems emphasizes the importance of including human inhabitants in conservation conversations.

14.
Curr Biol ; 31(16): 3671-3677.e3, 2021 08 23.
Artigo em Inglês | MEDLINE | ID: mdl-34237267

RESUMO

Most new infectious diseases emerge when pathogens transfer from animals to humans.1,2 The suspected origin of the COVID pandemic in a wildlife wet market has resurfaced debates on the role of wildlife trade as a potential source of emerging zoonotic diseases.3-5 Yet there are no studies quantitatively assessing zoonotic disease risk associated with wildlife trade. Combining data on mammal species hosting zoonotic viruses and mammals known to be in current and future wildlife trade,6 we found that one-quarter (26.5%) of the mammals in wildlife trade harbor 75% of known zoonotic viruses, a level much higher than domesticated and non-traded mammals. The traded mammals also harbor distinct compositions of zoonotic viruses and different host reservoirs from non-traded and domesticated mammals. Furthermore, we highlight that primates, ungulates, carnivores, and bats represent significant zoonotic disease risks as they host 132 (58%) of 226 known zoonotic viruses in present wildlife trade, whereas species of bats, rodents, and marsupials represent significant zoonotic disease risks in future wildlife trade. Thus, the risk of carrying zoonotic diseases is not equal for all mammal species in wildlife trade. Overall, our findings strengthen the evidence that wildlife trade and zoonotic disease risks are strongly associated, and that mitigation measures should prioritize species with the highest risk of carrying zoonotic viruses. Curbing the sales of wildlife products and developing principles that support the sustainable and healthy trade of wildlife could be cost-effective investments given the potential risk and consequences of zoonotic outbreaks.


Assuntos
Animais Selvagens/virologia , Comércio , Mamíferos/virologia , Pandemias/prevenção & controle , Zoonoses/transmissão , Animais , Reservatórios de Doenças/veterinária , Reservatórios de Doenças/virologia , Humanos , Desenvolvimento Sustentável , Zoonoses/epidemiologia , Zoonoses/prevenção & controle , Zoonoses/virologia
15.
PhytoKeys ; 163: 1-560, 2020.
Artigo em Inglês | MEDLINE | ID: mdl-37397271

RESUMO

A checklist of the grasses of India is presented, as compiled from survey of all available literature. Of the twelve subfamilies of grasses, ten are represented in India. Most subfamilies have been examined by taxonomic experts for up-to-date nomenclature. The list includes 1506 species plus infraspecific taxa and presents information on types, synonyms, distribution within India, and habit. Twelve new combinations are made, viz. Arctopoa tibetica (Munro ex Stapf) Prob. var. aristulata (Stapf) E.A. Kellogg, comb. nov.; Chimonocalamus nagalandianus (H.B. Naithani) L.G. Clark, comb. nov.; Chionachne digitata (L.f.) E.A. Kellogg, comb. nov.; Chionachne wallichiana (Nees) E.A. Kellogg, comb. nov.; Dinebra polystachyos (R. Br.) E.A. Kellogg, comb. nov.; Moorochloa eruciformis (Sm.) Veldkamp var. divaricata (Basappa & Muniv.) E.A. Kellogg, comb. nov.; Phyllostachys nigra (Lodd. ex Lindl.) Munro var. puberula (Miq.) Kailash, comb. & stat. nov.; Tzveleviochloa schmidii (Hook. f.) E.A. Kellogg, comb. nov.; Urochloa lata (Schumach.) C.E. Hubb. var. pubescens (C.E. Hubb.) E.A. Kellogg, comb. nov.; Urochloa ramosa (L.) T.Q. Nguyen var. pubescens (Basappa & Muniy.) E.A. Kellogg, comb. nov.; Urochloa semiundulata (Hochst. ex A. Rich.) Ashalatha & V.J. Nair var. intermedia (Basappa & Muniy.) E.A. Kellogg, comb. nov.

17.
20.
Oecologia ; 91(2): 239-244, 1992 Aug.
Artigo em Inglês | MEDLINE | ID: mdl-28313463

RESUMO

Pithecellobium pedicellare, a mimosoid legume, is a large canopy tree in the tropical rain forests of Costa Rica. We examined the pattern of variation in seed weight, germination date, hypocotyl length (stem), and rachis length (the first leaf) of the seedlings in this species. Seeds collected from widely dispersed individual trees at the La Selva Biological Station, Costa Rica, were randomly planted in blocks, and grown under controlled, indoor conditions for about 2 weeks. There-fore, we were able to quantify the effects of maternal family on mean seed weight and the effects of maternal family and microenvironment on the remaining traits examined. A significant effect of maternal family was detected for all traits. In particular, the maternal effects on germination date and seedling size traits which were consistently significant even after controlling the initial seed weight may indicate that the maternal effects reflect, at least to some extent, maternal genetic control over these traits. Despite overall strong maternal effects, the performance of maternal siblings, such as the rachis length, differed among blocks. The sensitivity of maternal siblings to the local environments may contribute to the maintenance of genetic variability in this highly outcrossing tropical species.

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