Publications by authors named "Tim R Baker"

Plants cope with the environment by displaying large phenotypic variation. Two spectra of global plant form and function have been identified: a size spectrum from small to tall species with increasing stem tissue density, leaf size, and seed mass; a leaf economics spectrum reflecting slow to fast returns on investments in leaf nutrients and carbon. When species assemble to communities it is assumed that these spectra are filtered by the environment to produce community level functional composition.

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Unlike most rivers globally, nearly all lowland Amazonian rivers have unregulated flow, supporting seasonally flooded floodplain forests. Floodplain forests harbor a unique tree species assemblage adapted to flooding and specialized fauna, including fruit-eating fish that migrate seasonally into floodplains, favoring expansive floodplain areas. Frugivorous fish are forest-dependent fauna critical to forest regeneration via seed dispersal and support commercial and artisanal fisheries.

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We describe the geographical variation in tree species composition across Amazonian forests and show how environmental conditions are associated with species turnover. Our analyses are based on 2023 forest inventory plots (1 ha) that provide abundance data for a total of 5188 tree species. Within-plot species composition reflected both local environmental conditions (especially soil nutrients and hydrology) and geographical regions.

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Article Synopsis
  • Amazonia's floodplain system is the largest and most biodiverse, but our understanding of its forest species and their unique roles is still limited, especially as changing flood patterns impact these communities.
  • About one-sixth of the tree diversity in Amazonia is specifically adapted to live in floodplain environments, indicating a significant ecological specialization within these forests.
  • The study emphasizes that the unique composition of floodplain forests is influenced by regional flooding patterns, highlighting the necessity of maintaining overall hydrological health to ensure the survival of Amazon's tree diversity and its essential ecosystem functions.
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Using 2.046 botanically-inventoried tree plots across the largest tropical forest on Earth, we mapped tree species-diversity and tree species-richness at 0.1-degree resolution, and investigated drivers for diversity and richness.

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Article Synopsis
  • Indigenous societies have occupied the Amazon for over 12,000 years, but their impact on the forest is still not fully understood.
  • New LIDAR technology has helped discover 24 pre-Columbian earthworks hidden under the forest, suggesting many more archaeological sites may exist.
  • The presence of 53 domesticated tree species linked to these earthworks indicates past human management of the forest, highlighting the significant influence ancient societies had on Amazonian ecosystems.
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In a time of rapid global change, the question of what determines patterns in species abundance distribution remains a priority for understanding the complex dynamics of ecosystems. The constrained maximization of information entropy provides a framework for the understanding of such complex systems dynamics by a quantitative analysis of important constraints via predictions using least biased probability distributions. We apply it to over two thousand hectares of Amazonian tree inventories across seven forest types and thirteen functional traits, representing major global axes of plant strategies.

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The Publisher regrets that this article is an accidental duplication of an article that has already been published, https://doi.org/10.1016/j.

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Amazonian forests are extraordinarily diverse, but the estimated species richness is very much debated. Here, we apply an ensemble of parametric estimators and a novel technique that includes conspecific spatial aggregation to an extended database of forest plots with up-to-date taxonomy. We show that the species abundance distribution of Amazonia is best approximated by a logseries with aggregated individuals, where aggregation increases with rarity.

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Article Synopsis
  • The study investigates how evolutionary diversification influences biodiversity distribution in tree species across the Americas.
  • It identifies that climate factors, specifically freezing temperatures, create a significant divide in tree lineages between tropical and extratropical environments.
  • The findings suggest that phylogenetic niche conservatism, where species maintain their ancestral environmental preferences, plays a crucial role in shaping tree biodiversity on a large scale.
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Background: In order to implement intervention strategies to prevent falls from height, epidemiological data are needed. The aim of this study was to map emergency presentations for falls from height in residents aged ≥40yr of the western region of Victoria, Australia.

Methods: Emergency presentations following a fall from height (≥1m) were obtained from electronic medical records for 2014-2016 inclusive.

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Tropical forests are known for their high diversity. Yet, forest patches do occur in the tropics where a single tree species is dominant. Such "monodominant" forests are known from all of the main tropical regions.

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Background: In order to develop and implement prevention strategies for falls, comprehensive epidemiological data are required. Therefore, this study mapped emergency presentations for falls across the western region of Victoria, Australia, encompassing urban, regional and rural areas.

Methods: This cross-sectional study utilised electronic data for emergency presentations following a fall from <1m for individuals aged ≥40yr during 2014-2016 inclusive.

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The mass of carbon contained in trees is governed by the volume and density of their wood. This represents a challenge to most remote sensing technologies, which typically detect surface structure and parameters related to wood volume but not to its density. Since wood density is largely determined by taxonomic identity this challenge is greatest in tropical forests where there are tens of thousands of tree species.

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Article Synopsis
  • Species distribution models (SDMs), like MaxEnt, often rely on natural history collections (NHCs) for data, but these collections can be spatially biased, affecting model accuracy.
  • A study tested the relationship between NHC distribution and a spatial abundance model (IDW) for Amazonian tree species, finding a weak positive correlation for most species analyzed.
  • The proposed new pipeline effectively reduced NHC inconsistencies and trimmed unnecessary data, offering a more conservative estimate of species occupancy, which is vital for large biodiversity assessments and conservation status evaluations.
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Estimates of extinction risk for Amazonian plant and animal species are rare and not often incorporated into land-use policy and conservation planning. We overlay spatial distribution models with historical and projected deforestation to show that at least 36% and up to 57% of all Amazonian tree species are likely to qualify as globally threatened under International Union for Conservation of Nature (IUCN) Red List criteria. If confirmed, these results would increase the number of threatened plant species on Earth by 22%.

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Forest inventory studies in the Amazon indicate a large terrestrial carbon sink. However, field plots may fail to represent forest mortality processes at landscape-scales of tropical forests. Here we characterize the frequency distribution of disturbance events in natural forests from 0.

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The vast extent of the Amazon Basin has historically restricted the study of its tree communities to the local and regional scales. Here, we provide empirical data on the commonness, rarity, and richness of lowland tree species across the entire Amazon Basin and Guiana Shield (Amazonia), collected in 1170 tree plots in all major forest types. Extrapolations suggest that Amazonia harbors roughly 16,000 tree species, of which just 227 (1.

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Developing high-quality scientific research will be most effective if research communities with diverse skills and interests are able to share information and knowledge, are aware of the major challenges across disciplines, and can exploit economies of scale to provide robust answers and better inform policy. We evaluate opportunities and challenges facing the development of a more interactive research environment by developing an interdisciplinary synthesis of research on a single geographic region. We focus on the Amazon as it is of enormous regional and global environmental importance and faces a highly uncertain future.

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*The rich ecology of tropical forests is intimately tied to their moisture status. Multi-site syntheses can provide a macro-scale view of these linkages and their susceptibility to changing climates. Here, we report pan-tropical and regional-scale analyses of tree vulnerability to drought.

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Amazon forests are a key but poorly understood component of the global carbon cycle. If, as anticipated, they dry this century, they might accelerate climate change through carbon losses and changed surface energy balances. We used records from multiple long-term monitoring plots across Amazonia to assess forest responses to the intense 2005 drought, a possible analog of future events.

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