Long-term fertilization determines different metabolomic profiles and responses in saplings of three rainforest tree species with different adult canopy position

Imbalance-P paper contact with Albert Gargallo: [email protected] changes in metabolome provided strong evidence that different nutrients limit different species in different ways. With increasing P availability, the two canopy species shifted their metabolome towards larger investment in protection mechanisms, whereas with increasing N availability, the sub-canopy species increased its primary metabolism. The results highlighted the proportional distinct use of different nutrients by different species and the resulting different metabolome profiles in this high diversity community are consistent with the ecological niche theory

Long-Term Impact of Liming on Soil C and N in a Fertile Spruce Forest Ecosystem

Liming can counteract acidification in forest soils, but the effects on soil C and N pools and fluxes over long periods are less well understood. Replicated plots in an acidic and N-rich 40-year-old Norway spruce (Picea abies) forest in SW Sweden (Hasslov) were treated with 0, 3.45 and 8.75 Mg ha(-1)of dolomitic lime (D0, D2 and D3) in 1984. Between 1984 and 2016, soil organic C to 30 cm depth increased by 28 Mg ha(-1)(30% increase) in D0 and decreased by 9 Mg ha(-1)(9.4% decrease) in D3. The change in D2 was not significant (+ 2 Mg ha(-1)). Soil N pools changed proportionally to those in soil C pools. The C and N changes occurred almost exclusively in the top organic layer. Non-burrowing earthworms responded positively to liming and stimulated heterotrophic respiration in this layer in both D2 and D3. Burrowing earthworms in D3 further accelerated C and N turnover and loss of soil. The high soil C and N loss at our relatively N-rich site differs from studies of N-poor sites showing no C and N loss. Earthworms need both high pH and N-rich food to reach high abundance and biomass. This can explain why liming of N-rich soils often results in decreasing C and N pools, whereas liming of N-poor soils with few earthworms will not show any change in soil C and N. Extractable nitrate N was always higher in D3 than in D2 and D0. After 6 years (1990), potential nitrification was much higher in D3 (197 kg N ha(-1)) than in D0 (36 kg N ha(-1)), but this difference decreased during the following years, when also the unlimed organic layers showed high nitrification potential. Our experiment finds that high-dose liming of acidic N-rich forest soils produces an initial pulse of soil heterotrophic respiration and increases in earthworm biomass, which together cause long-term declines in soil C and N pools

Genetics and Genomics of Forest Trees

Forest tree genetics and genomics are advancing at an accelerated rate, thanks to recent developments in high-throughput, next-generation sequencing capabilities, and novel biostatistical tools. Population and landscape genetics and genomics have seen the rise of new approaches implemented in large-scale studies that employ the use of genome-wide sampling. Such studies have started to discern the dynamics of neutral and adaptive variation in nature and the processes that underlie spatially explicit patterns of genetic and genomic variation in nature. The continuous development of genetic maps in forest trees and the expansion of QTL and association mapping approaches contribute to the unravelling of the genotype-phenotype relationship and lead to marker-assisted and genome-wide selection. However, major challenges lie ahead. Recent literature suggests that species demography and genetic diversity have been affected both by climatic oscillations and anthropogenically induced stresses in a way calls into question the possibility of future adaptation. Moreover, the pace of contemporary environmental change presents a great challenge to forest tree populations and their ability to adapt, taking into consideration their life history characteristics. Several questions emerge that include, but are not limited to, the interpretation of forest tree genome surveillance and their structural/functional properties, the adaptive and neutral processes that have shaped forest tree genomes, the analysis of phenotypic traits relevant to adaptation (especially adaptation under contemporary climate change), the link between epigenetics/epigenomics and phenotype/genotype, and the use of genetics/genomics as well as genetic monitoring to advance conservation priorities

Arctic hydroclimate variability during the last 2000 years : current understanding and research challenges

Reanalysis data show an increasing trend in Arctic precipitation over the 20th century, but changes are not homogenous across seasons or space. The observed hydro-climate changes are expected to continue and possibly accelerate in the coming century, not only affecting pan-Arctic natural ecosystems and human activities, but also lower latitudes through the atmospheric and ocean circulations. However, a lack of spatiotemporal observational data makes reliable quantification of Arctic hydroclimate change difficult, especially in a long-term context. To understand Arctic hydroclimate and its variability prior to the instrumental record, climate proxy records are needed. The purpose of this review is to summarise the current understanding of Arctic hydroclimate during the past 2000 years. First, the paper reviews the main natural archives and proxies used to infer past hydroclimate variations in this remote region and outlines the difficulty of disentangling the moisture from the temperature signal in these records. Second, a comparison of two sets of hydroclimate records covering the Common Era from two data-rich regions, North America and Fennoscandia, reveals inter- and intra-regional differences. Third, building on earlier work, this paper shows the potential for providing a high-resolution hydroclimate reconstruction for the Arctic and a comparison with last-millennium simulations from fully coupled climate models. In general, hydroclimate proxies and simulations indicate that the Medieval Climate Anomaly tends to have been wetter than the Little Ice Age (LIA), but there are large regional differences. However, the regional coverage of the proxy data is inadequate, with distinct data gaps in most of Eurasia and parts of North America, making robust assessments for the whole Arctic impossible at present. To fully assess pan-Arctic hydroclimate variability for the last 2 millennia, additional proxy records are required.Peer reviewe

Stable Isotopes in Tree Rings

This Open Access volume highlights how tree ring stable isotopes have been used to address a range of environmental issues from paleoclimatology to forest management, and anthropogenic impacts on forest growth. It will further evaluate weaknesses and strengths of isotope applications in tree rings. In contrast to older tree ring studies, which predominantly applied a pure statistical approach this book will focus on physiological mechanisms that influence isotopic signals and reflect environmental impacts. Focusing on connections between physiological responses and drivers of isotope variation will also clarify why environmental impacts are not linearly reflected in isotope ratios and tree ring widths. This volume will be of interest to any researcher and educator who uses tree rings (and other organic matter proxies) to reconstruct paleoclimate as well as to understand contemporary functional processes and anthropogenic influences on native ecosystems. The use of stable isotopes in biogeochemical studies has expanded greatly in recent years, making this volume a valuable resource to a growing and vibrant community of researchers

24-Epibrassinolide positively modulates leaf tissues and antioxidant system attenuating the deleterious effects on photosynthetic machinery in rice plants under simulated acid rain.

Ministério da Educação e Universidade Federal Rural da Amazônia.A chuva ácida causa danos significativos às plantas de arroz, afetando o maquinário fotossintético e o crescimento. O 24-epibrassinolídeo (EBR) é um esteroide orgânico usado em baixas concentrações que regula positivamente o crescimento das plantas e atenua os efeitos deletérios relacionados às mudanças ambientais. O objetivo deste estudo foi investigar se o tratamento exógeno com 24-epibrassinolídeo pode aliviar os efeitos negativos da chuva ácida simulada (SAR) e o possível mecanismo de tolerância envolvido, avaliando a fluorescência das clorofilas, as trocas gasosas, o sistema antioxidante e as variáveis anatômicas foliares. O experimento foi randomizado com quatro tratamentos, sendo duas chuvas ácidas simuladas (H2SO4 0 e 0,5 M, descritas como - SAR e + SAR, respectivamente) e duas concentrações de brassinoesteroides (EBR 0 e 100 nM, descritas como - EBR e + EBR, respectivamente). Nossos resultados mostraram que as plantas expostas à SAR sofreram interferências negativas; no entanto, plantas tratadas com EBR apresentaram benefícios na fluorescência das clorofilas, aliviando a fotoinibição no fotossistema II e protegendo contra os danos causados pelo desequilíbrio das espécies reativas de oxigênio. Além disso, o EBR promoveu aumentos nas trocas gasosas claramente relacionadas à regulação estomática, melhorando a captação e distribuição de CO2 nos espaços intercelulares. Esta pesquisa revelou que o EBR atenuou os efeitos negativos da SAR, aumentando as atividades das enzimas antioxidantes (superóxido dismutase, catalase, ascorbato peroxidase e peroxidase), reduzindo os danos nas membranas dos tilacoides, confirmados pelo aumento de clorofilas e carotenoides. Finalmente, os efeitos do EBR observados em plantas sob SAR demonstram que esta substância modulou positivamente importantes estruturas anatômicas ligadas à proteção das folhas, aumentando a quantidade de tricomas, cera epicuticular e área de aerênquima. Esses resultados fornecem evidências de que o EBR conferiu tolerância em plantas de arroz expostas à SAR.Acid rain causes significant damages to rice plants, affecting photosynthetic machinery and growth. 24-epibrassinolide (EBR) is an organic steroid that used at low concentrations positively regulates plant growth and mitigates deleterious effects connected to environmental changes. The aim of this study was to investigate whether exogenous treatment with 24-epibrassinolide can alleviate the negative effects of the simulated acid rain (SAR) and the possible tolerance mechanism involved, evaluating the chlorophyll fluorescence, gas exchange, antioxidant system and leaf anatomical variables. The experiment was randomized with four treatments, being two simulated acid rain (0 and 0.5 M H2SO4, described as – SAR and + SAR, respectively) and two concentrations of brassinosteroids (0 and 100 nM EBR, described as – EBR and + EBR, respectively). Our results showed that plants exposed to SAR suffered negative interferences; however, EBR-treated plants presented benefits on chlorophyll fluorescence, alleviating the photoinhibition in the photosystem II and protection against damages caused by the imbalance of the reactive oxygen species. Additionally, EBR promoted increases in gas exchange clearly linked to stomatal regulation, improving uptake and distribution of CO2 in intercellular spaces. This research revealed that EBR attenuated the negative effects of SAR, increasing the activities of the antioxidant enzymes (superoxide dismutase, catalase, ascorbate peroxidase and peroxidase), reducing the damages on tilacoid membrane, confirmed by increases in chlorophylls and carotenoids. Finally, the EBR effects observed in plants under SAR demonstrate that this substance positively modulated important anatomical structures linked to leaf protection, increasing the amount of trichomes, epicuticular wax and aerenchyma area. These results provide evidence that EBR conferred tolerance on rice plants exposed to SAR

Biodiversidade liquénica e biomonitorização de poluição atmosférica

Doutoramento BiologiaEsta tese debruça-se sobre a biodiversidade de líquenes epífitos de pinhais dunares portugueses e sobre uso de líquenes como biomonitores de poluição atmosférica nesse habitat. A Mata Nacional das Dunas de Quiaios (Figueira da Foz) foi o ponto de partida dos estudos de biodiversidade efetuados nesta tese, mas alguns deles estenderam-se à maior parte da costa portuguesa. Como resultado, encontrou-se uma espécie nova para a ciência, Lecanora sorediomarginata Rodrigues, Terrón & Elix, epifítica sobre Pinus pinaster Aiton e P. pinea L, que se encontra distribuída na maior parte da costa. Esta espécie caracteriza-se morfologicamente por um talo crustáceo, de cor esbranquiçada a acinzentada ou esverdeada e que desenvolve sorálios a partir de pequenas verrugas marginais. Quimicamente caracteriza-se pela presença dos ácidos 3,5-dicloro-2'-O-metilnorestenospórico [maior], 3,5-dicloro-2-O-metilanziaico [menor], 3,5-dicloro-2-O-metilnordivaricático [menor], 5-cloro-2'-Ometilanziaico [traço] e úsnico [traço]; atranorina [menor] e cloroatranorina [menor]. É quimicamente semelhante a L. lividocinerea Bagl., com a qual apresenta afinidades filogenéticas com base na análise da sequência ITS do rDNA, e a L. sulphurella Hepp. Adicionalmente, espécies Chrysothrix flavovirens Tønsberg e Ochrolechia arborea (Kreyer) Almb, também se encontraram epifíticas sobre P. pinaster e P. pinea em vários pinhais ao longo da costa, representando novos registos para a flora liquénica portuguesa, bem como a espécie Lepraria elobata Tønsberg encontrada epifítica sobre P. pinaster apenas nas Dunas de Quiaios. Além disso, as espécies Hypotrachyna lividescens (Kurok.) Hale e H. pseudosinuosa (Asahina) Hale encontraram-se epifíticas sobre P. pinaster e outros forófitos nas Dunas de Quiaios, constituindo novos registos para a flora liquénica da Península Ibérica. Estes resultados põe em evidência a importância dos pinhais dunares como habitat para líquenes epífitos. Num estudo conduzido entre janeiro e julho de 2008 num pinhal dunar (Mata do Urso, Figueira da Foz), em cuja bordadura existe uma fábrica de celulose de papel, usaram-se transplantes de líquenes da espécie Flavoparmelia caperata (L.) Hale para avaliar a acumulação de trinta e três elementos putativamente emitidos por fábricas de papel e pasta de papel. A cinética da fluorescência da clorofila a foi estudada nos líquenes transplantados, através da análise dos parâmetros Fv/Fm, F0, Fm, qP, NPQ, PSII, e Exc, de forma a avaliar os efeitos decorrentes da acumulação de elementos na vitalidade dos líquenes. Pretendeu-se avaliar se a acumulação de elementos e a cinética da fluorescência da clorofila a variavam significativamente com o local e o tempo de exposição, tendo em consideração os resultados obtidos de transplantes colocados num local de referência (Dunas de Quiaios) durante o mesmo período de tempo. (Continua no verso) resumo A maior parte dos elementos — Al, B, Ba, Ca, Co, Cr, Cu, Fe, Hg, Li, Mg, Mn, Mo, Na, Ni, P, S, Sb, Sc, Sr, Ti e V — ocorreu em concentrações significativamente mais elevadas nos transplantes expostos a 500 m da fábrica. Cerca de metade dos elementos estudados — B, Ba, Cr, Fe, Hg, Mg, Mn, Mo, Na, P, Pb, S, Sb e V — encontraram-se em concentrações significativamente mais elevadas nos transplantes expostos durante 180 dias. O solo foi identificado como uma fonte parcial da maior parte dos elementos. Os parâmetros Fv/Fm, Fm, PSII e Exc variaram significativamente com o local e/ou com o tempo de exposição. Observou-se um decréscimo significativo nos parâmetros Fv/Fm e Fm nos transplantes expostos a 500 e 1000 da fábrica, e também naqueles expostos durante 135 e 180 dias. Observou-se também um decréscimo significativo nos parâmetros PSII e Exc expostos durante 180 dias. Estes parâmetros correlacionaram-se de forma negativa e significativa com a acumulação de elementos: Fv/Fm: B, Ba, Co, Fe, Hg, Mg, Mn, Mo, N, P, S, Sb e Zn; Fm: Ba, Co, Hg, Mn, Mo, N, P, S, Sb e Zn; PSII: N e P; Exc: Mn, N, P e S. Estudos acerca da diversidade liquénica efetuados nos mesmos locais onde os transplantes foram colocados no local impactado, revelaram um menor valor de diversidade liquénica a 500 m da fábrica, que foi também o único local onde se encontraram espécies nitrófilas, o que se poderá dever à deposição de amónia e/ou poeiras. À semelhança de outros estudos, este trabalho confirma que os líquenes podem ser usados com sucesso em estudos de biomonitorização, mesmo em locais florestados. Além disso, traz também informações adicionais sobre como a acumulação de elementos pode influenciar a cinética da fluorescência da clorofila a em líquenes.This thesis focuses on the biodiversity of epiphytic lichens of Portuguese pine forests on sand dunes, and on the use of lichens as biomonitors of atmospheric pollution in this habitat. Mata Nacional das Dunas de Quiaios (Figueira da Foz) was the starting location of the biodiversity studies undertaken during this thesis, but some were extended to most of the Portuguese coast. As a result a new species to science, Lecanora sorediomarginata Rodrigues, Terrón & Elix was discovered epiphytic on Pinus pinaster Aiton and P. pinea L, in most of the coast. It is characterised morphologically by a crustose whitish-grey to greenish thallus developing soralia from small, marginal warts and chemically by the presence of 3,5-dichloro-2'-O-methylnorstenosporic acid [major], 3,5-dichloro- 2-O-methylanziaic acid [minor], 3,5-dichloro-2-O-methylnordivaricatic acid [minor], 5-chloro-2'-O-methylanziaic acid [trace], atranorin [minor], chloroatranorin [minor], and usnic acid [trace]. It is chemically similar to L. lividocinerea Bagl., to which it shows phylogenetic affinities based on ITS rDNA sequence analysis, and to L. sulphurella Hepp. Additionally, Chrysothrix flavovirens Tønsberg and Ochrolechia arborea (Kreyer) Almb, were also found epiphytic on P. pinaster and P. pinea in several pine forests along the coast, representing new records for Portuguese lichen flora, as well as that of Lepraria elobata, which was found epiphytic on P. pinaster only at Dunas de Quiaios. Furthermore, Hypotrachyna lividescens (Kurok.) Hale e H. pseudosinuosa (Asahina) Hale were found epiphytic on P. pinaster and other phorophytes at Dunas de Quiaios, and were new records for the lichen flora of the Iberian Peninsula. These results indicate the importance of pine forests on sand dunes has habitats for epiphytic lichens. In a study conducted in a pine forest on sand dunes (Mata do Urso, Figueira da Foz), impacted by a pulp mill at its border, between January and July 2008, lichen transplants of the species Flavoparmelia caperata (L.) Hale were used to evaluate the accumulation of thirty-three elements putatively emitted by paper and pulp mill industry. Chlorophyll a fluorescence kinetics studies were performed in the transplanted lichens, through the analysis of the parameters Fv/Fm, F0, Fm, qP, NPQ, PSII, and Exc in order to evaluate the effect of elemental accumulation on lichen vitality. It was intended to evaluate if elemental accumulation and chlorophyll a fluorescence kinetics varied significantly with site and period of exposure, taking into account the results from transplants performed in a reference location (Dunas de Quiaios) during the same period of time. Most elements — Al, B, Ba, Ca, Co, Cr, Cu, Fe, Hg, Li, Mg, Mn, Mo, Na, Ni, P, S, Sb, Sc, Sr, Ti and V — were found in significantly higher concentrations in the transplants exposed at 500 m of distance from the point source. Nearly half of the elements — B, Ba, Cr, Fe, Hg, Mg, Mn, Mo, Na, P, Pb, S, Sb, and V — were also found in significantly higher concentrations in the transplants exposed during 180 days. (Continues on the verse) abstract Soil was identified as a partial source for most elements. The chlorophyll a fluorescence kinetics parameters Fv/Fm, Fm, PSII, and Exc varied significantly with site and/or period of exposure. Fv/Fm and Fm were significantly decreased in the transplants exposed at 500 and 1000 m from the pulp mill and in those exposed during 135 and 180 days. Both, PSII and Exc decreased significantly after 180 days of exposure. Significant negative correlations were identified between these parameters and the accumulation of elements: Fv/Fm: B, Ba, Co, Fe, Hg, Mg, Mn, Mo, N, P, S, Sb, and Zn; Fm: Ba, Co, Hg, Mn, Mo, N, P, S, Sb, and Zn; PSII: N and P; Exc: Mn, N, P, and S. Lichen diversity studies performed in the same locations where lichen transplants were placed at the impacted location revealed a lower lichen diversity value at the 500 m, which was also the only site were nitrophylous species were found, what could be due to the deposition of ammonia and/or dust. Similarly to other studies, this work confirms that lichens can be successfully used in biomonitoring studies, even in forested locations. Furthermore, it provides additional information on how chlorophyll a fluorescence kinetics of lichens can be influenced by elemental accumulation

ASSESSING FOREST RESPONSES TO CLIMATE CHANGE AND RESOLVING PRODUCTIVITY MEASUREMENTS ACROSS SPATIAL SCALES

Informed decisions regarding forest and carbon resources require knowledge of the impacts of environmental changes on forest productivity. We also need to reconcile the diverging productivity estimates that are presently available. This dissertation assembles two publications addressing the impacts of climate change on forest productivity and one exploring the relationship between three estimates of forest productivity. In the first chapter, I evaluated whether forests have responded to recent changes in climatic conditions. Through combining published evidence I show that forests have responded to changes in the patterns of light, water, and temperatures over the last half of the 20th century. Most published studies showed a positive growth trend. Negative growth trends were found for drier study areas. Conclusions on the greening of the world\u27s forests, are difficult due to poor geographical coverage and measurement method disparity. In the second chapter, I compared three productivity estimation methods (two ground-based and one satellite-based) using 166 sites in Austria. Results of disturbance-free projections show the relevance of each method to actual site productivity and their combined usefulness in identifying the most appropriate scale for monitoring climate forcings. Each estimation method provides information on a portion of the underlying actual NPP. In the last chapter, I explore the effect of three IPCC climate change scenarios on forests of the US Northern Rockies. Results show an increase in growing season length and in water stress, and a decrease in snow quantities and in number of days with ground snow for all forests by 2089. Under the driest and warmest scenario, the majority of the sites became carbon sources, and I identify a water/temperature tipping point, past which system stored carbon drastically declines. For these disturbance-free projections, water availability drove the system. In this dissertation, I resolve a otential source of conflict among forest productivity estimates; combined, these estimates lead to a broader understanding of productivity. I also present evidence that forests are already responding to climate change, and that more drastic changes are likely in the future