Search Results (6)

Climate change is altering temperature and precipitation regimes in Argentina, with potential consequences for regeneration and persistence of forest tree species, emphasizing the importance of ex situ seed conservation. We evaluated interannual variation in seed traits, desiccation tolerance, storage behavior, and longevity of Cedrela balansae C. DC. and C. fissilis Vell. (Meliaceae), two endangered native species of subtropical rainforests in Argentina. Both species produced desiccation-tolerant seeds, independently of collection year, seed traits, or climatic conditions. Depending on the species, seed traits and longevity varied across years and showed strong relationships with temperature and precipitation, particularly during seed development. Cedrela balansae seeds are medium-lived seeds and have high longevity under standard seed banking conditions, suggesting strong potential for long-term ex situ conservation. Cedrela fissilis seeds are short-lived seeds and have high sensitivity to the storage environment. Correlations among climatic variables and seed traits and longevity parameters suggest that future warming and drying environments may shorten the window for germination and seedling establishment, with species-specific responses depending on climatic conditions during seed development. These results highlight the importance of climate effects in determining seed traits and seed longevity and emphasize the role of seed banking as a critical conservation strategy under climate change. Full article

Elevational gradients are widely studied to understand environmental variability and species distribution. Ants play vital roles in ecosystems and are frequently included in elevational biogeography studies. Despite their ecological importance and well-documented elevational patterns, little is known about their temporal variability across elevations. We surveyed ground and arboreal ants in austral summer, autumn, spring, and winter in a subtropical rainforest of Lamington National Park, Queensland, Australia. Given their physiological and microhabitat differences, ground and arboreal ants may exhibit distinct spatiotemporal patterns. Using litter extraction for ground ants and bark spraying for arboreal ants, we collected 14,916 individuals from 124 species. Species richness and abundance were lowest in austral winter, particularly for arboreal ants. Both richness and abundance declined with elevation, and this pattern remained consistent across seasons. While seasonal and elevational differences significantly influenced species composition, seasonal variation did not cause major shifts in the elevational distribution of ground or arboreal ants. A total of 43 species were identified as indicators of specific elevations, with species such as Notoncus capitatus and Colobostruma biconvexa being specialists of low elevations, and undescribed Monomorium and Discothyrea species being specialists of high elevations. In contrast, only two species were identified as seasonal indicators, which were undescribed Tapinoma and Anonychomyrma species, specialists of the warm season. Our findings suggest that ants reduce activity in winter but maintain stable elevational distributions regardless of season or microhabitat use, making their distributions a reliable indicator of their climatic niches. Full article

Functional traits are pivotal for understanding the functional niche within plant communities. Yet, the relationship between the functional niches of typical forest plant communities across different climatic zones, as defined by functional traits, and their association with community and phylogenetic structures remains elusive. In this study, we examined 215 woody species, incorporating 11 functional traits spanning leaf economy, mechanical support, and reproductive phenology, gathered from forests in four climatic zones from tropical, subtropical, warm-temperate to cold-temperate zones in China and supplemented by the literature. We quantified the functional niche hypervolume (FNH), reflecting the multidimensional functional niche variability. We then probed into the correlation between the FNH and community and phylogenetic structures of forests. Our findings reveal that species richness significantly influences the geographic variance of functional niche space in forest vegetation across different climatic zones. Specifically, a community’s species richness correlates positively with the functional niche breadth occupied by the community species. The FNH of woody plants across diverse forest types shows significant associations with both the mean phylogenetic distance (MPD) and the mean nearest phylogenetic taxon distance (MNTD) of the communities. There is a progressive increase in tropical rainforest (TF), subtropical evergreen deciduous broad-leaved mixed forest (SF), and warm-temperate coniferous broad-leaved mixed forest (WF), followed by a decline in the cold-temperate coniferous forest (CF). This pattern suggests potential environmental filtering in CF, which may constrain the spatial extent of plant functional niches. Our research underscores the substantial variability in the FNH across China’s typical forest vegetation, highlighting the complex interplay between functional traits, community richness, and phylogenetic distance. Full article

The Amazon Basin is the largest rainforest in the world, and studying the rainfall in this region is crucial for understanding the functioning of the entire rainforest ecosystem and its role in regulating the regional and global climate. This work is part of the application of complex networks, which refer to a network modeled by graphs and are characterized by their high versatility, as well as the extraction of key information from the system under study. The main objective of this article is to examine the precipitation system in the Amazon basin during the austral summer. The networks are defined by nodes and connections, where each node represents a precipitation time series, while the connections can be represented by different similarity functions. For this study, three rainfall networks were created, which differ based on the correlation function used (Pearson, Spearman, and Kendall). By comparing these networks, we can identify the most effective method for analyzing the data and gain a better understanding of rainfall’s spatial structure, thereby enhancing our knowledge of its impact on different Amazon basin regions. The results reveal the presence of three important regions in the Amazon basin. Two areas were identified in the northeast and northwest, showing incursions of warm and humid winds from the oceans and favoring the occurrence of large mesoscale systems, such as squall lines. Additionally, the eastern part of the central Andes may indicate an outflow region from the basin with winds directed toward subtropical latitudes. The networks showed a high level of activity and participation in the center of the Amazon basin and east of the Andes. Regarding information transmission, the betweenness centrality identified the main pathways within a basin, and some of these are directly related to certain rivers, such as the Amazon, Purus, and Madeira. Indicating the relationship between rainfall and the presence of water bodies. Finally, it suggests that the Spearman and Kendall correlation produced the most promising results. Although they showed similar spatial patterns, the major difference was found in the identification of communities, this is due to the meridional differences in the network’s response. Overall, these findings highlight the importance of carefully selecting appropriate techniques and methods when analyzing complex networks. Full article

Climate change is a negative global externality that threatens economic growth. In our study, we firstly reviewed the transmission mechanisms of climate change affecting economic growth based on existing literature. Secondly, we respectively used the fixed effect method and the panel vector autoregression method to test the short-run and long-run effects of climate change on the economic growth of 44 countries in six climatic zones in Africa, from 2000 to 2019. The results showed that temperature has inverted U-shaped effects on the economic growth of countries in tropical rainforest and tropical dry climate zones, but a U-shaped effect in warm temperate humid regions. The heterogeneity test was based on industrial and geographical perspectives. Climate change has a significant inverted U-shaped effect on agricultural and services output in tropical rainforest and tropical dry climate zones. Moreover, climate change positively impacts economic growth in coastal regions, but has no significant impact on inland countries. Lastly, the long-run results indicate that tropical rainforest and subtropical humid regions show a greater ability to adapt to climate change, while tropical desert regions show greater volatility resilience in response to climate change. Full article

Here we investigate the interaction between ecology and climate concerning the distribution of rainforest species differentially distributed along altitudinal gradients of eastern Australia. The potential distributions of the two species closely associated with different rainforest types were modelled to infer the potential contribution of post-glacial warming on spatial distribution and altitudinal range shift. Nothofagus moorei is an integral element of cool temperate rainforest, including cloud forests at high elevation. This distinct climatic envelope is at increased risk with future global warming. Elaeocarpus grandis on the other hand is a lowland species and typical element of subtropical rainforest occupying a climatic envelope that may shift upwards into areas currently occupied by N. moorei. Climate envelope models were used to infer range shift differences between the two species in the past (21 thousand years ago), current and future (2050) scenarios, and to provide a framework to explain observed genetic diversity/structure of both species. The models suggest continuing contraction of the highland cool temperate climatic envelope and expansion of the lowland warm subtropical envelope, with both showing a core average increase in elevation in response to post-glacial warming. Spatial and altitudinal overlap between the species climatic envelopes was at a maximum during the last glacial maximum and is predicted to be a minimum at 2050. Full article