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1.
Nat Commun ; 11(1): 5635, 2020 11 06.
Artigo em Inglês | MEDLINE | ID: mdl-33159062

RESUMO

More tree species can increase the carbon storage capacity of forests (here referred to as the more species hypothesis) through increased tree productivity and tree abundance resulting from complementarity, but they can also be the consequence of increased tree abundance through increased available energy (more individuals hypothesis). To test these two contrasting hypotheses, we analyse the most plausible pathways in the richness-abundance relationship and its stability along global climatic gradients. We show that positive effect of species richness on tree abundance only prevails in eight of the twenty-three forest regions considered in this study. In the other forest regions, any benefit from having more species is just as likely (9 regions) or even less likely (6 regions) than the effects of having more individuals. We demonstrate that diversity effects prevail in the most productive environments, and abundance effects become dominant towards the most limiting conditions. These findings can contribute to refining cost-effective mitigation strategies based on fostering carbon storage through increased tree diversity. Specifically, in less productive environments, mitigation measures should promote abundance of locally adapted and stress tolerant tree species instead of increasing species richness.


Assuntos
Clima , Ecossistema , Árvores/crescimento & desenvolvimento , Biodiversidade , Carbono/metabolismo , Florestas , Árvores/classificação , Árvores/metabolismo
2.
Sci Rep ; 10(1): 15577, 2020 09 23.
Artigo em Inglês | MEDLINE | ID: mdl-32968165

RESUMO

Broad-leaved trees are widely distributed from tropical to temperate zones in China, reference collections of phytoliths from these taxa are crucial for the precise reconstruction of paleoenvironments and the study of early plant resource exploitation. However, not much has been published on the phytoliths produced by modern broad-leaved trees. In this study, we collected samples of 110 species that cover the common species distributed in Northern and Southern China, and extracted phytoliths from leaves, twigs and fruits, in order to investigate the phytoliths types and production in these species. We found that only 58 species were phytoliths producers, and that 23 distinct phytoliths morphotypes could be recognized. The results showed that phytoliths types and production in Northern and Southern China could be similar in the two regions. Through analyzing previously published data and our data, ELONGATE BRACHIATE GENICULATE, POLYGONAL TABULAR, ELONGATE FACETATE, TRACHEARY ANNULATE/FACETATE GENICULATE and TRACHEARY ANNULATE/FACETATE CLAVIFORM have been proposed to be the potential diagnostic types for broad-leaved trees in general. This study provided a preliminary reference of phytoliths in modern broad-leaved trees, and could be used in the identification of phytoliths in sediments and archaeological contexts.


Assuntos
Folhas de Planta/química , Especificidade da Espécie , Árvores/classificação , Arqueologia , China , Sedimentos Geológicos/química , Folhas de Planta/classificação , Árvores/química
3.
PLoS One ; 15(5): e0233292, 2020.
Artigo em Inglês | MEDLINE | ID: mdl-32421694

RESUMO

An important challenge for silvicultural practices is the conservation of tree diversity while fulfilling the traditional objectives of forest management, most notably timber harvesting. The purpose of this study was to compare the tree diversity before and after the application of silvicultural treatments in a temperate forest in northern Mexico. Fifteen experimental plots, each measuring 2500 m2, were established to evaluate the immediate effect of four silvicultural treatments. These treatments were identified by their levels of management: intensive (clearcut, removal 100%), semi-intensive (removal of 59-61% of basal area), conservative (removal of 29-31% of basal area), and a control group. New forest guidelines, in contrast to conventional approaches, were applied to the semi-intensive and conservative treatments based on health and diversity conditions. Basal area, canopy cover, tree and total volume were measured in each plot. The Importance Value Index, alpha diversity, and evenness were estimated before and after treatments. Eighteen species belonging to five genera and five families were found in the study area. The species with the highest ecological values were Pinus durangensis, P. teocote, Quercus sideroxyla, and Quercus convallata with IVI numbers between 13.6 and 24.5%. Alpha diversity was intermediate (Margalef: 2.9 to 3.8), while dominance and evenness were above average compared to other studies (Simpson: 0.69 to 0.77; Shannon-Wiener: 1.44 to 1.6; Pielou: 0.76 to 0.85). The species evenness index in the conservative treatment was high (Sorensen, Jaccard, quantitative Sorensen and Morisita-Horn; 88 to 99%), although abundance decreased. Overall, there were no significant differences in IVI values and diversity indicators before and after treatments, with the exception of the clearcut treatment. When associating the diversity indices with stand variables, only the Pielou's evenness index showed a significant relationship between them. We concluded that both the conservative and semi-intensive treatments did not generate significant changes in tree diversity, but the former had slightly higher alpha diversity indices. These results can provide a better insight on silvicultural practices and their effects on species composition.


Assuntos
Conservação dos Recursos Naturais/métodos , Agricultura Florestal/métodos , Florestas , Biodiversidade , Ecossistema , México , Árvores/classificação
4.
PLoS One ; 15(4): e0231790, 2020.
Artigo em Inglês | MEDLINE | ID: mdl-32310971

RESUMO

Seemingly empty spaces in various archaeological settings have left many unanswered questions. This paper focuses on the appearance, maintenance and possible function of a large empty area situated at the summit plateau of the Iron Age oppidum Bibracte in France. Multidisciplinary research of the infill of the ditch that delimited this area in the 1st century BC has provided evidence on the primary function and the formation processes of the structure itself, and for the reconstruction of the appearance, maintenance and function of the area it enclosed. The results allow us to gain insight into a variety of topics, including the role of trees, hygiene measures and waste management strategies at this urbanised hilltop centre. This paper demonstrates that multi-proxy analyses provide detailed insight into the function of archaeological features in a local environmental context and the potential of such approaches in archaeology.


Assuntos
Arqueologia , Urbanização/história , Arqueologia/métodos , Diatomáceas/classificação , França , Sedimentos Geológicos/análise , Fenômenos Geológicos , História Antiga , Humanos , Datação Radiométrica/métodos , Árvores/classificação , Gerenciamento de Resíduos/história
5.
BMC Evol Biol ; 20(1): 44, 2020 04 19.
Artigo em Inglês | MEDLINE | ID: mdl-32306974

RESUMO

BACKGROUND: The Mexican hand tree or Canac (Chiranthodendron pentadactylon) is a temperate tree species of cloud and pine-oak forests of southern Mexico and Guatemala. Its characteristic hand-shaped flower is used in folk medicine and has constituted the iconic symbol of the Sociedad Botánica de México since 1940. Here, the evolutionary history of this species was estimated through phylogeographic analyses of nuclear DNA sequences obtained through restriction site associated DNA sequencing and ecological niche modeling. Total genomic DNA was extracted from leaf samples obtained from a representative number (5 to 10 per sampling site) of individuals distributed along the species geographic range. In Mexico, population is comprised by spatially isolated individuals which may follow the trends of cloud forest fragmentation. By contrast, in Guatemala Chiranthodendron may constitute a canopy dominant species near the Acatenango volcano. The distributional range of this species encompasses geographic provinces separated by the Isthmus of Tehuantepec. The objectives of the study were to: (i) estimate its genetic structure to define whether the observed range disjunction exerted by the Isthmus of Tehuantepec translates into separate populations, (ii) link population divergence timing and demographic trends to historical climate change, and (iii) test hypotheses related to Pleistocene refugia. RESULTS: Patterns of genetic diversity indicated high levels of genetic differentiation between populations separated by the Isthmus. The western and eastern population diverged approximately 0.873 Million years ago (Ma). Demographic analyses supported a simultaneous split from an ancestral population and rapid expansion from a small stock approximately 0.2 Ma corresponding to a glacial period. The populations have remained stable since the LIG (130 Kilo years ago (Ka)). Species distribution modelling (SDM) predicted a decrease in potential distribution in the Last Interglacial (LIG) and an increase during the Last Glacial Maximum (LGM) (22 Ka), Mid-Holocene (6 Ka) and present times. CONCLUSIONS: Divergence time estimations support the hypothesis that populations represent Quaternary relict elements of a species with broader and northernmost distribution. Pleistocene climatic shifts exerted major influence on the distribution of populations allowing dispersion during episodes of suitable climatic conditions and structuring during the first interglacial with a time period length of 100 Kilo years (Kyr) and the vicariant influence of the Isthmus. Limited demographic expansion and population connectivity during the LGM supports the moist forest hypothesis model.


Assuntos
Evolução Biológica , Malvaceae/classificação , Floresta Úmida , Árvores/classificação , Núcleo Celular , Mudança Climática , DNA de Plantas , Ecossistema , Humanos , Malvaceae/genética , México , Filogeografia , Análise de Sequência de DNA , Árvores/genética
6.
Appl Opt ; 59(2): 558-563, 2020 Jan 10.
Artigo em Inglês | MEDLINE | ID: mdl-32225341

RESUMO

Tree trunk diameter and tree species are two of the most important parameters in analyzing trees in urban areas and forests. Conventionally, diameters have been measured manually, and the species were determined by sight. An automated tool for these assessments was developed. Tree trunks are automatically detected from captured stereo images. Then, tree trunk diameters are estimated, and the species are determined. The developed graphical user interface tool enables fast and accurate estimation even while one is walking, which reduces the time spent in measuring trees.


Assuntos
Árvores/anatomia & histologia , Árvores/classificação , Processamento de Imagem Assistida por Computador , Análise de Componente Principal , Especificidade da Espécie , Interface Usuário-Computador
7.
PLoS One ; 15(2): e0229448, 2020.
Artigo em Inglês | MEDLINE | ID: mdl-32109946

RESUMO

The Atlantic rainforest of Brazil is one of the global terrestrial hotspots of biodiversity. Despite having undergone large scale deforestation, forest cover has shown signs of increases in the last decades. Here, to understand the degradation and regeneration history of Atlantic rainforest remnants near São Paulo, we combine a unique dataset of very high resolution images from Worldview-2 and Worldview-3 (0.5 and 0.3m spatial resolution, respectively), georeferenced aerial photographs from 1962 and use a deep learning method called U-net to map (i) the forest cover and changes and (ii) two pioneer tree species, Cecropia hololeuca and Tibouchina pulchra. For Tibouchina pulchra, all the individuals were mapped in February, when the trees undergo mass-flowering with purple and pink blossoms. Additionally, elevation data at 30m spatial resolution from NASA Shuttle Radar Topography Mission (SRTM) and annual mean climate variables (Terraclimate datasets at ∼ 4km of spatial resolution) were used to analyse the forest and species distributions. We found that natural forests are currently more frequently found on south-facing slopes, likely because of geomorphology and past land use, and that Tibouchina is restricted to the wetter part of the region (southern part), which annually receives at least 1600 mm of precipitation. Tibouchina pulchra was found to clearly indicate forest regeneration as almost all individuals were found within or adjacent to forests regrown after 1962. By contrast, Cecropia hololeuca was found to indicate older disturbed forests, with all individuals almost exclusively found in forest fragments already present in 1962. At the regional scale, using the dominance maps of both species, we show that at least 4.3% of the current region's natural forests have regrown after 1962 (Tibouchina dominated, ∼ 4757 ha) and that ∼ 9% of the old natural forests have experienced significant disturbance (Cecropia dominated).


Assuntos
Biodiversidade , Conservação dos Recursos Naturais , Monitoramento Ambiental , Redes Neurais de Computação , Floresta Úmida , Árvores/crescimento & desenvolvimento , Especificidade da Espécie , Árvores/classificação
8.
Nat Commun ; 11(1): 545, 2020 Jan 28.
Artigo em Inglês | MEDLINE | ID: mdl-31992718

RESUMO

Severe droughts have the potential to reduce forest productivity and trigger tree mortality. Most trees face several drought events during their life and therefore resilience to dry conditions may be crucial to long-term survival. We assessed how growth resilience to severe droughts, including its components resistance and recovery, is related to the ability to survive future droughts by using a tree-ring database of surviving and now-dead trees from 118 sites (22 species, >3,500 trees). We found that, across the variety of regions and species sampled, trees that died during water shortages were less resilient to previous non-lethal droughts, relative to coexisting surviving trees of the same species. In angiosperms, drought-related mortality risk is associated with lower resistance (low capacity to reduce impact of the initial drought), while it is related to reduced recovery (low capacity to attain pre-drought growth rates) in gymnosperms. The different resilience strategies in these two taxonomic groups open new avenues to improve our understanding and prediction of drought-induced mortality.


Assuntos
Secas , Árvores/crescimento & desenvolvimento , Adaptação Fisiológica , Mudança Climática , Cycadopsida/crescimento & desenvolvimento , Ecologia , Florestas , Magnoliopsida/crescimento & desenvolvimento , Mortalidade , Solo/química , Especificidade da Espécie , Estresse Fisiológico , Análise de Sobrevida , Árvores/classificação , Água
9.
FEMS Microbiol Ecol ; 96(2)2020 02 01.
Artigo em Inglês | MEDLINE | ID: mdl-31825516

RESUMO

Despite numerous studies on plant endophytes, little is known about fungal communities associated with different aboveground tissues of living trees. We used high-throughput sequencing to compare the diversity and community structure of fungi inhabiting leaves, branches and trunks of Alnus incana and Corylus avellana growing at three hemiboreal forest sites. Our analysis revealed that tree organs are the main determinants of the structure of fungal communities, whereas the effects of host species and locality remained secondary and negligible, respectively. The structure of fungal communities in trunks was the most distinct compared to that in leaves and branches. The foliar fungal communities were more similar within than between individual trees, implying that certain fungi may grow through parts of the tree crown. The weak effect of locality compared to host organs and species identity suggests that the structural variation of fungal communities in the aboveground parts of trees depends mainly on deterministic factors rather than dispersal limitation.


Assuntos
Florestas , Micobioma/genética , Árvores/microbiologia , Biodiversidade , Endófitos/classificação , Endófitos/genética , Endófitos/isolamento & purificação , Fungos/classificação , Fungos/genética , Fungos/isolamento & purificação , Especificidade de Hospedeiro , Componentes Aéreos da Planta/microbiologia , Árvores/anatomia & histologia , Árvores/classificação
10.
Mol Biol Evol ; 37(3): 695-710, 2020 03 01.
Artigo em Inglês | MEDLINE | ID: mdl-31693149

RESUMO

A long-standing goal of evolutionary biology is to understand the mechanisms underlying the formation of species. Of particular interest is whether or not speciation can occur in the presence of gene flow and without a period of physical isolation. Here, we investigated this process within Hawaiian Metrosideros, a hypervariable and highly dispersible woody species complex that dominates the Hawaiian Islands in continuous stands. Specifically, we investigated the origin of Metrosideros polymorpha var. newellii (newellii), a riparian ecotype endemic to Hawaii Island that is purportedly derived from the archipelago-wide M. polymorpha var. glaberrima (glaberrima). Disruptive selection across a sharp forest-riparian ecotone contributes to the isolation of these varieties and is a likely driver of newellii's origin. We examined genome-wide variation of 42 trees from Hawaii Island and older islands. Results revealed a split between glaberrima and newellii within the past 0.3-1.2 My. Admixture was extensive between lineages within Hawaii Island and between islands, but introgression from populations on older islands (i.e., secondary gene flow) did not appear to contribute to the emergence of newellii. In contrast, recurrent gene flow (i.e., primary gene flow) between glaberrima and newellii contributed to the formation of genomic islands of elevated absolute and relative divergence. These regions were enriched for genes with regulatory functions as well as for signals of positive selection, especially in newellii, consistent with divergent selection underlying their formation. In sum, our results support riparian newellii as a rare case of incipient ecological speciation with primary gene flow in trees.


Assuntos
Myrtaceae/classificação , Proteínas de Plantas/genética , Árvores/classificação , Sequenciamento Completo do Genoma/métodos , Fluxo Gênico , Especiação Genética , Ilhas Genômicas , Hawaii , Myrtaceae/genética , Seleção Genética , Árvores/genética
11.
Ecotoxicol Environ Saf ; 189: 110021, 2020 Feb.
Artigo em Inglês | MEDLINE | ID: mdl-31830604

RESUMO

The failure of the Fundão dam, the largest environmental disaster in the world's mining sector, was responsible for releasing millions of cubic meters of iron ore tailings into the environment. It affected thousands of hectares of the Atlantic Forest domain, one of the biodiversity hotspots for conservation. Considering the urgency to restore the flora of the affected area, we evaluated the effects that iron ore tailings from the Fundão reservoir have on the germination and initial growth of tree species native to the Atlantic Forest in the Rio Doce basin. We demonstrated that the tailings do not affect the seed germination, but do negatively interfere with plant growth. Lower biomass production, height, leaf area, chlorophyll concentration and photosynthesis as well as high concentration of iron was observed in plants grown in the tailings. Thus, we investigated if these deleterious effects were due to the presence of potentially toxic metals or nutritional deficiency imposed by low fertility of the tailings. We concluded that reduced growth was a result of nutritional limitations due to low nutrient availability, low organic matter content and low cation exchange capacity of the tailings. This conclusion was further supported by the application of fertilization, which reversed the deleterious effect of the waste on the growth of plants, assuring physiological levels of iron and nutrients in the shoot. Thus, this strategy should be considered for in situ recovery projects aiming to improve the performance of native plants.


Assuntos
Solo/química , Árvores/crescimento & desenvolvimento , Biomassa , Recuperação e Remediação Ambiental , Fertilização , Ferro/análise , Ferro/metabolismo , Mineração , Nutrientes/análise , Nutrientes/deficiência , Nutrientes/metabolismo , Floresta Úmida , Poluentes do Solo/análise , Poluentes do Solo/metabolismo , Árvores/classificação , Árvores/metabolismo
12.
Environ Monit Assess ; 192(1): 43, 2019 Dec 13.
Artigo em Inglês | MEDLINE | ID: mdl-31836941

RESUMO

Using satellite data to extract forest structure mapping parameters assists forest management. In this research, structural parameters including species, density, canopy, and gaps were extracted from SPOT-7 satellite data over Hyrcanian forests (Iran). A detailed ground inventory was initially conducted, over 12 × 1 ha (100 m × 100 m) plots, in which tree coordinates were plotted, using a differential global positioning system (DGPS), along with data on tree species, diameter-at-breast-height and height, as well as canopy dimensions, and canopy gap shapes, sizes, and positions, for each plot. Then, spectral transformations, vegetation indices, and simple spectral ratios were extracted from SPOT-7 data, and a supervised, pixel-based classification method and a support-vector machine algorithm were used to classify and determine tree species types. In addition, canopy tree borders and gaps were classified, using an object-based method, and tree densities per unit area were determined, using the canopy gravity center. Finally, the original ground data was used to perform an accuracy assessment on the extracted information, with the results showing that forest type could be determined with 95% accuracy and a Kappa coefficient of 0.8. Canopy and gap coverage achieved an overall accuracy of 91% (Kappa coefficient: 0.7), and tree densities per hectare were determined, on average, to be 47 trees fewer than reality. In conclusion, we have shown that forest structural parameters could be extracted, with good accuracy, using a combination of pixel- and object-based methods applied to SPOT-7 imaging.


Assuntos
Monitoramento Ambiental/métodos , Imagens de Satélites , Florestas , Irã (Geográfico) , Árvores/classificação
13.
PLoS One ; 14(11): e0225331, 2019.
Artigo em Inglês | MEDLINE | ID: mdl-31770399

RESUMO

Myanmar undergoes rapid urban expansion and experiences its negative impacts, often due to the loss of urban green spaces. National and local authorities lack sufficient knowledge, capacity and plans on how to preserve urban green spaces and benefit from their ecosystem services, with such gaps being particularly pronounced in the smaller secondary cities. This study focuses in such as secondary city, Pyin Oo Lwin, and analyzes land use and land cover (LULC) change, tree diversity and carbon stored in aboveground and belowground biomass, and soil. We focus on the main green spaces of the city, which contain different configurations of urban forest, grassland and agricultural land. Remote sensing analysis tracked LULC change between 1988 and 2018, and showed the extensive increase of built-up area, and the decline of urban forests and urban farms. Even though a substantial amount of green spaces has been converted to built-up land, the remaining urban green spaces are still serving as an important habitat for many different tree species, with a total of 82 species from 35 families observed in the different green spaces. Furthermore, these green spaces contain significant carbon stocks, which are, however, highly variable: botanical garden (383.67 t/ha), coffee farms (355.64 t/ha), monasteries (277.14 t/ha), golf course (208.45 t/ha), and seasonal farms (123.22 t/ha). Nevertheless, the extensive LULC change has reduced carbon stocks from 2.41 Mt (1988) to 1.65 Mt (2018). The findings of this study provide a better understanding of LULC change in secondary cities of Myanmar, and build an evidence base on how urban green spaces preservation and green infrastructure development can contribute to green economic transitions, and sustainable, resilient, and low-carbon cities in the country.


Assuntos
Carbono/análise , Monitoramento Ambiental/métodos , Árvores/classificação , Biodiversidade , Sequestro de Carbono , Mianmar , Tecnologia de Sensoriamento Remoto , Reforma Urbana
14.
Nat Commun ; 10(1): 4757, 2019 10 18.
Artigo em Inglês | MEDLINE | ID: mdl-31628336

RESUMO

Recent progress in remote sensing provides much-needed, large-scale spatio-temporal information on habitat structures important for biodiversity conservation. Here we examine the potential of a newly launched satellite-borne radar system (Sentinel-1) to map the biodiversity of twelve taxa across five temperate forest regions in central Europe. We show that the sensitivity of radar to habitat structure is similar to that of airborne laser scanning (ALS), the current gold standard in the measurement of forest structure. Our models of different facets of biodiversity reveal that radar performs as well as ALS; median R² over twelve taxa by ALS and radar are 0.51 and 0.57 respectively for the first non-metric multidimensional scaling axes representing assemblage composition. We further demonstrate the promising predictive ability of radar-derived data with external validation based on the species composition of birds and saproxylic beetles. Establishing new area-wide biodiversity monitoring by remote sensing will require the coupling of radar data to stratified and standardized collected local species data.


Assuntos
Biodiversidade , Florestas , Radar , Tecnologia de Sensoriamento Remoto/métodos , Árvores/fisiologia , Animais , Aves/classificação , Aves/fisiologia , Besouros/classificação , Besouros/fisiologia , Conservação dos Recursos Naturais/métodos , Modelos Teóricos , Reprodutibilidade dos Testes , Análise Espaço-Temporal , Árvores/classificação
15.
Mol Biol Rep ; 46(6): 6547-6556, 2019 Dec.
Artigo em Inglês | MEDLINE | ID: mdl-31583570

RESUMO

Rhodoleia Champion ex Hooker is one of the most primitive relict genera of Hamamelidaceae, a key family exploited to understand the origin and early evolution of flowering plants. Genomic simple sequence repeats (SSRs) were developed for R. championii to perform genetic diversity, phylogeographical structure or even systematic evolution studies of the genus. Among the 278,743 contigs (105,758,242 bps) de novo assembled from the low-coverage whole genome sequencing of R. championii, a total of 9106 SSRs were detected in 8370 contigs, and SSR primer pairs were successfully designed for 6677 SSRs. Among the 110 selected primer pairs, 41 were amplified successfully in the preliminary test of SSR screening. Further amplification of these 41 primer pairs across the 122 individuals collected from six populations of the three Rhodoleia species showed that 32 and 40 SSR markers can be amplified in Vietnam and Jinping populations of R. parvipetala, 41, 33, and 41 SSR markers in Boluo, Hongkong and Xinyi populations of R. championii, 25 SSR markers in Fugong population of R. forrestii, and 20 SSR markers demonstrated to be polymorphic across the three species. Genetic analysis for these 20 polymorphic SSRs showed that Allele number (A) ranged from four to 13 and polymorphic information content (PIC) ranged from 0.479 to 0.876 across the three species. At the population level, observed heterozygosity (HO) ranged from 0.000 to 1.000, and expected heterozygosity (HE) ranged from 0.091 to 0.851. In the present study, we provided the first whole-genome sequencing database for the species R. championii, identified ample SSR loci with designed primers, and revealed that 20 of the 110 selected SSRs were polymorphic across three Rhodoleia species. These provide valuable resources for future studies on genetic study, species delimitation, phylogeography, and conservation of this genus.


Assuntos
Repetições de Microssatélites , Árvores/classificação , Sequenciamento Completo do Genoma/métodos , DNA de Plantas/genética , Desequilíbrio de Ligação , Especificidade da Espécie , Árvores/genética
16.
Nat Commun ; 10(1): 4590, 2019 10 14.
Artigo em Inglês | MEDLINE | ID: mdl-31611554

RESUMO

Intact forests provide diverse and irreplaceable ecosystem services that are critical to human well-being, such as carbon storage to mitigate climate change. However, the ecosystem functions that underpin these services are highly dependent on the woody vegetation-animal interactions occurring within forests. While vertebrate defaunation is of growing policy concern, the effects of vertebrate loss on natural forest regeneration have yet to be quantified globally. Here we conduct a meta-analysis to assess the direction and magnitude of defaunation impacts on forests. We demonstrate that real-world defaunation caused by hunting and habitat fragmentation leads to reduced forest regeneration, although manipulation experiments provide contrasting findings. The extirpation of primates and birds cause the greatest declines in forest regeneration, emphasising their key role in maintaining carbon stores, and the need for national and international climate change and conservation strategies to protect forests from defaunation fronts as well as deforestation fronts.


Assuntos
Biodiversidade , Conservação dos Recursos Naturais/métodos , Ecossistema , Florestas , Árvores/fisiologia , Animais , Biomassa , Aves/fisiologia , Carbono/metabolismo , Mudança Climática , Humanos , Modelos Biológicos , Primatas/fisiologia , Árvores/classificação , Vertebrados/fisiologia
17.
Proc Natl Acad Sci U S A ; 116(39): 19318-19323, 2019 09 24.
Artigo em Inglês | MEDLINE | ID: mdl-31501347

RESUMO

The emissions, deposition, and chemistry of volatile organic compounds (VOCs) are thought to be influenced by underlying landscape heterogeneity at intermediate horizontal scales of several hundred meters across different forest subtypes within a tropical forest. Quantitative observations and scientific understanding at these scales, however, remain lacking, in large part due to a historical absence of canopy access and suitable observational approaches. Herein, horizontal heterogeneity in VOC concentrations in the near-canopy atmosphere was examined by sampling from an unmanned aerial vehicle (UAV) flown horizontally several hundred meters over the plateau and slope forests in central Amazonia during the morning and early afternoon periods of the wet season of 2018. Unlike terpene concentrations, the isoprene concentrations in the near-canopy atmosphere over the plateau forest were 60% greater than those over the slope forest. A gradient transport model constrained by the data suggests that isoprene emissions differed by 220 to 330% from these forest subtypes, which is in contrast to a 0% difference implemented in most present-day biosphere emissions models (i.e., homogeneous emissions). Quantifying VOC concentrations, emissions, and other processes at intermediate horizontal scales is essential for understanding the ecological and Earth system roles of VOCs and representing them in climate and air quality models.


Assuntos
Atmosfera/química , Butadienos/análise , Florestas , Hemiterpenos/análise , Compostos Orgânicos Voláteis/análise , Brasil , Estações do Ano , Árvores/classificação , Árvores/fisiologia
18.
PLoS One ; 14(8): e0219753, 2019.
Artigo em Inglês | MEDLINE | ID: mdl-31381566

RESUMO

In order to establish effective conservation strategy, drivers of local and regional patterns of biodiversity need to be understood. The composition of local biodiversity is dependent on a number of factors including evolution and redistribution of lineages through dispersal and environmental heterogeneity. Brazilian canga is characterised by a ferrugineous substrate, found both in the Iron Quadrangle of Minas Gerais and in the Carajás mountains in Amazonia. Canga is one of several specialised habitat types comprising Brazilian campo rupestre, a montane vegetation found within or adjacent to several major Brazilian bioregions, including the Atlantic Forest and Amazonia, with exceptionally high levels of diversity and endemism arising from both history of dispersal and environmental variation. In order to inform biodiversity conservation for canga, and more broadly for campo rupestre, we performed floristic and phylogenetic analyses investigating affinities between 28 sites on different substrates (canga and quartzite) and geographic locations (Carajás, Pará [Amazonia]; Cadeia do Espinhaço, Minas Gerais; Chapada Diamantina, Bahia). Through analysis of 11204 occurrences of 4705 species of angiosperms, we found that Amazonian Carajás canga plant communities formed a cohesive group, distinct from species assemblages found in Eastern Brazil (Minas Gerais, Bahia), either on canga or quartzite. The phylogenetic megatree of species across all sites investigated shows associations between certain clades and Amazonian canga, with few shared species between the Amazonian Carajás and Eastern Brazil sites, while the floristic comparison shows high levels of heterogeneity between sites. The need for reserves for Amazonian Carajás canga has been recognized and addressed by the creation of a national park. However, current sampling does not provide sufficient reassurance that the canga areas now benefitting from full legal protection adequately represent the regional canga flora.


Assuntos
Conservação dos Recursos Naturais , Ecossistema , Plantas , Geografia , Filogenia , Plantas/classificação , América do Sul , Inquéritos e Questionários , Árvores/classificação
20.
Sci Total Environ ; 687: 1065-1072, 2019 Oct 15.
Artigo em Inglês | MEDLINE | ID: mdl-31412444

RESUMO

We analyzed the Italian National Forest Inventory data set to evaluate the interdependence of forest productivity, tree species richness (used to indicate biodiversity), climate, and soil factors. We tested the hypotheses that the relationship between biodiversity and forest productivity is positive and significant for all forests in Italy and whether the relationship is the same for forests growing in the temperate and Mediterranean bioclimatic domains (regions) of Italy. We used generalized additive models to explore the univariate response curves for the data and then performed structural equation modeling (SEM) and multi-group SEM analyses to evaluate the relationship between biodiversity and productivity. We found that the SEM model for the entire dataset explained about 60% of the variation in forest productivity. In addition, the variation associated with species richness was greater than variation due to climatic factors and the variation in climate factors was greater than the variation in soil factors (all relative to their contributions to productivity). The multi-group SEM showed a more predominant effect of biodiversity and climate on productivity in Mediterranean compared to temperate forests. In both cases, we observed a moderate effect of soil (factors) on forest productivity. Our results support the hypothesis that increasing tree diversity in forests could help reduce the effects of climate warming and enhance ecosystem productivity in the Mediterranean region.


Assuntos
Biodiversidade , Clima , Florestas , Árvores/classificação , Biomassa , Mudança Climática , Ecossistema , Monitoramento Ambiental , Itália , Região do Mediterrâneo , Árvores/fisiologia
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