Intra- and interspecific ecophysiological responses to waterlogging stress in two contrasting waterlogging-tolerant arbor species.

At present, establishing planted forests, typically composed of not more than two tree species, to avoid forest losses has received increasing attention. In addition, investigating the impact of environmental stress such as waterlogging on different planting patterns is essential for improving wetland ecosystem resilience. Knowledge about the impact of waterlogging on planted forests is crucial for developing strategies to mitigate its adverse effects. Here, we conducted experimentally a simulated pure and mixed planting system composed of two contrasting WL-tolerant species (Cleistocalyx operculatus and Syzygium cumini) to determine their ecophysiological responses based on the type of interaction. Results showed that the aboveground growth performance of S. cumini was better than that of C. operculatus under well-watered conditions regardless of the planting model, which is contrary to the belowground accumulation that was significantly improved in C. operculatus. Intra- and interspecific interactions in different planting models facilitated the growth performance of C. operculatus while provoking a significant competition in S. cumini under waterlogging. Such phenomenon was explained through the remarkable ability of C. operculatus to naturally increase its root network under stress on non-stress conditions compared with S. cumini. In this study, two main factors are proposed to play key roles in the remarkable performance of C. operculatus compared with S. cumini following the planting model under waterlogging. The high level of nitrogen and phosphor absorption through C. operculatus primary roots and the significant starch biosynthesis constituted the key element that characterized the facilitation or competition within the intra- or interspecific interactions shown in C. operculatus compared with S. cumini. Furthermore, the intraspecific competition is more pronounced in S. cumini than in C. operculatus when grown in a pure planting pattern, particularly when subjected to waterlogging. However, when the two species are planted together, this competition is alleviated, resulting in enhanced waterlogging tolerance.

Effect of Huntiella decorticans and drought on Nothofagus dombeyi seedlings.

In the temperate forests of Patagonia, Argentina, Nothofagus dombeyi, commonly known as Coihue, has shown sensitivity to intense drought events, leading to mortality. Studies have been conducted on Coihue decline and mortality using a variety of approaches, including the role of extreme heat waves and drought, pests and pathogens, particularly the fungus Huntiella decorticans. This work aimed to evaluate survival, vitality, necrosis extension and growth response of inoculated and non-inoculated Coihue seedlings from different provenances exposed to different soil moisture levels. To achieve this goal, 96 Coihue seedlings from 2 different provenances were assigned to 8 different experimental treatments. Treatments were composed of the presence or absence of H. decorticans and different soil moisture content conditions, dry, wet and the exposure to dry condition at different times of the experiment. Both dry conditions and H. decorticans had negative effects on the survival and growth rate of Coihue. The combination of both factors resulted in 100 % mortality, regardless of the plants' geographical provenances. Mortality began to be observed 3 months after pathogen inoculation, during the warmest month. Necrosis extension produced by the pathogen was similar for most of the inoculated treatments. The treatment under wet condition during the experiment but subjected to dry condition in the previous growing season presented lower necrosis extension (8.4 ±â€…3.2 %), than the other treatments. The radial increase was also affected by the treatments and geographical provenance, being those plants exposed to dry conditions which grew less (0.19 ±â€…0.21 mm). This study enhances our understanding of the plant-pathogen interaction. According to our results, Coihue may become more susceptible to mortality, when H. decorticans and water deficit conditions act synergistically.

Dynamics of Endogenous Auxin and Its Role in Somatic Embryogenesis Induction and Progression in Cork Oak.

Somatic embryogenesis (SE) is a feasible in vitro regeneration system with biotechnological applications in breeding programs, although, in many forest species, SE is highly inefficient, mainly due to their recalcitrance. On the other hand, SE represents a valuable model system for studies on cell reprogramming, totipotency acquisition, and embryogenic development. The molecular mechanisms that govern the transition of plant somatic cells to embryogenic cells are largely unknown. There is increasing evidence that auxins mediate this transition and play a key role in somatic embryo development, although data on woody species are very limited. In this study, we analyzed the dynamics and possible role of endogenous auxin during SE in cork oak (Quercus suber L.). The auxin content was low in somatic cells before cell reprogramming, while it increased after induction of embryogenesis, as revealed by immunofluorescence assays. Cellular accumulation of endogenous auxin was also detected at the later stages of somatic embryo development. These changes in auxin levels correlated with the expression patterns of the auxin biosynthesis (QsTAR2) and signaling (QsARF5) genes, which were upregulated after SE induction. Treatments with the inhibitor of auxin biosynthesis, kynurenine, reduced the proliferation of proembryogenic masses and impaired further embryo development. QsTAR2 and QsARF5 were downregulated after kynurenine treatment. Our findings indicate a key role of endogenous auxin biosynthesis and signaling in SE induction and multiplication, as well as somatic embryo development of cork oak.

Improved assessment of baseline and additionality for forest carbon crediting.

In the California compliance cap-and-trade carbon market, improved forest management (IFM) projects generate carbon credits in the initial reporting period if their initial carbon stocks are greater than a baseline. This baseline is informed by a "common practice" stocking value, which represents the average carbon stocks of surveyed privately owned forests that are classified into the same general forest type by the California Air Resources Board. Recent work has called attention to the need for more ecologically informed common practice carbon stocking values for IFM projects, particularly those in areas with sharp ecological gradients. Current methods for estimating common practice produce biases in baseline carbon values that lead to a clustering of IFM projects in geographical areas and ecosystem types that in fact support much greater forest carbon stocks than reflected in the common practice. This phenomenon compromises additionality, or the increases in carbon sequestration or decreases in carbon emissions that would not have occurred in the absence of carbon crediting. This study seeks to expand upon recent work on this topic and establish unbiased common practice estimates along sharp ecological gradients using methods that do not rely upon discrete forest classification. We generated common practice values for credited IFM projects in the Southern Cascades using a principal components analysis on species composition over an extensive forest inventory to determine the ecological similarity between inventoried forests and IFM project sites. Our findings strengthen the results of recent research suggesting common practice bias and adverse selection. At several sites, even after controlling for private ownership, 100% of the initial carbon stocks could be explained by ecological variables. This result means that improved management did not preserve or increase carbon stocks above what was typical, suggesting that no carbon offsets should have been issued for these sites. This result reveals greater bias than that been found at project sites in this region by research that has used discrete forest categorization.

Current status of the cryopreservation of embryogenic material of woody species.

Cryopreservation, or the storage at liquid nitrogen temperatures (-196°C), of embryogenic cells or somatic embryos allows their long-term conservation without loss of their embryogenic capacity. During the last decade, protocols for cryopreservation of embryogenic material of woody species have been increasing in number and importance. However, despite the large experimental evidence proved in thousands of embryogenic lines, the application for the large-scale conservation of embryogenic material in cryobanks is still limited. Cryopreservation facilitates the management of embryogenic lines, reducing costs and time spent on their maintenance, thus limiting the risk of the appearance of somaclonal variation or contamination. Somatic embryogenesis in combination with cryopreservation is especially useful to preserve the juvenility of lines while the corresponding clones are being field-tested. Hence, when tree performance has been evaluated, selected varieties can be propagated from the cryostock. The traditional method of slow cooling or techniques based on vitrification are mostly applied procedures. For example, slow cooling methods are widely applied to conserve embryogenic lines of conifers. Desiccation based procedures, although simpler, have been applied in a smaller number of species. Genetic stability of the cryopreserved material is supported by multiloci PCR-derived markers in most of the assayed species, whereas DNA methylation status assays showed that cryopreservation might induce some changes that were also observed after prolonged subculture of the embryogenic lines. This article reviews the cryopreservation of embryogenic cultures in conifers, fruit species, deciduous forest species and palms, including a description of the different cryopreservation procedures and the analysis of their genetic stability after storage in liquid nitrogen.

Seed Quality and Vigor of Germination of Moringa oleífera Lam. in Saline Stress

Abstract Moringa oleifera Lam., is a tree species that has several purposes of use, standing out in the recovery of degraded areas and the use of seeds as biodsorbents in water clarification. However, ony a little is known about the behavior of seed germination under saline conditions, common in soils and water in the Brazilian Northeast. Thus, the objective was to evaluate the increment of water during the soaking and seed germination of M. oleífera that were submitted to different electrical conductivity of the irrigation water. The work was developed following a completely randomized design, with stress simulation employing saline solutions at the concentrations of 0.0; 3.0; 6.0 and 9.0 dS m-1. To determine the soaking curve, the water increment of the soaked seeds in the different saline solutions was monitored at regular intervals with four replications per treatment. To characterize the physiological quality of the seeds, the percentage, first count, speed index, average time and average germination speed were evaluated. The M. oleífera is tolerant to the effect of salinity during the germination phase, however seed vigor is reduced as a function of increased salinity. Soaking the seeds makes begin the phase II of the germination process around 10 hours and extends for up to 50 hours, when phase III begins, they absorb approximately 0.2 g of water and require 86 hours for germination. Salinity reduces the absorption and increase of water in the seeds.

Variability and genetic structure in fragments of Eugenia involucrata De Candolle established through microsatellite markers / Variabilidade e estruturação genética em fragmentos de Eugenia involucrata de Candolle utilizando marcadores microssatélites

ABSCTRACT: Eugenia involucrata DC. is a forest species with high environmental and economic potential. The objective of this study was to quantify the genetic variability and analyzed the genetic structure of three natural fragments located in the central region of the Rio Grande do Sul state, Brazil. We used four microsatellite loci developed for the congener species Eugenia uniflora and using GenAlEx 6.5 software, parameters of genetic variability and its partition among and within fragments were estimated for each locus. We observed high levels of genetic variability (3.67 alleles per locus; HO = 0.815; HE = 0.625; FIS = −0.294), most of which (93%) were distributed within the fragments, suggesting that these individuals came from a single original population. Gene flow between fragments was high (2.35 to 4.56 migrants per generation), resulting in low genetic differentiation indexes (FST values ranging from 0.052 to 0.096). The fragments showed high genetic variability, distributed within the remnants themselves, and low genetic differentiation. Our results have repercussions for planning locally adapted germplasm collections for forest restoration programs, thereby avoiding the implantation of populations with an exogamous depression.

RESUMO: Eugenia involucrata DC. é uma espécie florestal com elevado potencial ambiental e econômico. O presente trabalho teve por objetivo quantificar a variabilidade e analisar a estruturação genética em três fragmentos naturais localizados na região central do estado do Rio Grande do Sul, Brasil. Com o emprego de quatro locos microssatélites desenvolvidos para a espécie congênere Eugenia uniflora e usando-se o software GenAlEx 6.5, foram estimados parâmetros de variabilidade genética, para cada loco, e sua partição entre e dentro dos fragmentos. Foram observados altos índices de variabilidade genética (3,67 alelos por loco; HO = 0,815; HE = 0,625; FIS = -0,294), com a maior proporção (93%) distribuída dentro dos fragmentos, sugerindo que os indivíduos estudados são provenientes de uma única população original. O fluxo gênico foi elevado entre os fragmentos, variando de 2,35 a 4,56 migrantes por geração, resultando em baixo índice de diferenciação genética (FST), entre 0,052 a 0,096. Os fragmentos estudados apresentam elevada variabilidade genética, a maior parte distribuída dentro dos próprios remanescentes, e baixa diferenciação genética. Os resultados observados têm repercussões no planejamento de coleta de germoplasma com adaptação local para programas de restauração florestal, assim evitando a implantação de populações com depressão exogâmica.

Pattern and spatial associations of commercial trees in the Amazon / Padrão e associações espaciais de árvores comerciais da Amazônia

ABSTRACT: This study was conducted to establish the pattern and the spatial associations of the Amazon commercial tree groups. In a region extending across 2,000 ha in the Tapajós National Forest (FNT), Pará, a forest census was conducted. The census included commercial trees of perimeter at breast height (PBH), equal to or greater than 158 cm and the Cartesian coordinates of their bearings. Using Ripley's K function, the spatial pattern was discerned, with 5 m radius being assumed, and maximum distances varying up to 1,500 m. Then, with 99.8% probability for both, 500 Monte Carlo simulations were performed for the univariate K function, and 500 toroidal simulations were done for the bivariate function.The commercial tree groups, which revealed an aggregated spatial pattern in a minimum of approximately 50% of the analysis distance were namely, Astronium lecointei, Bagassa guianensis, Couratari guianensis, Manilkara huberi, Mezilaurus itauba, and Vochysia maxima. In Brazil, the commercial tree groups, based on the commercialization criteria for tropical trees show random and aggregated spatial patterns with associations of spatial independence.

RESUMO: O objetivo do trabalho foi determinar o padrão espacial e a associação espacial de grupos de árvores comerciais da Amazônia.Realizou-se um censo florestal em uma área de 2.000 ha localizada na Floresta Nacional do Tapajós (FNT), Pará. No censo coletou-se a circunferência à altura do peito (CAP), igualou superior a 158 cm e as coordenadas cartesianas das árvores comerciais. Para determinar o padrão espacial foi utilizada a função K de Ripley assumindo um raio de 5 m, variando a uma distância máxima de 1.500 m. Para a função K univariada foram realizadas 500 simulações Monte Carlo e para a função bivariada foram realizadas 500 simulações toroidais, ambas com 99,8% de probabilidade. Os grupos de árvores comerciais que possuíram padrão espacial agregado em no mínimo 50% da distância de análise foram Astronium lecointei, Bagassa guianensis, Couratari guianensis, Manilkara huberi, Mezilaurus itauba, Vochysia maxima. Grupos de árvores comerciais, segundo critério de comercialização para árvores tropicais no Brasil, seguem um padrão espacial aleatório e agregado e possuem associações espaciais de independência espacial.

How do clonal plantlets of mate respond to different substrate compositions and shading levels? / Como as mudas clonais de erva-mate respondem a diferentes composições de substrato e níveis de sombreamento?

Mate (Ilex paraguariensis A. St.-Hil) is an arboreal species of great economic and socio-environmental importance in South American countries. This specie presents several difficulties during seminal propagation, and studies related to plantlet production by vegetative propagation are fundamental for obtaining homogenous mate plantations with high leaf productivity. Therefore, the present study aimed to evaluate the effects of substrate and shading levels on the morphophysiological quality of mate plantlets produced by mini-cuttings. Rooted mini-cuttings of four mate clones were cultivated on commercial substrate, subsurface soil and vermiculite (2:1:1 v/v/v), commercial substrate and subsurface soil (2:1 v/v) or subsurface soil, cattle manure and carbonized rice hulls (2:1:1 v/v/v). After 120 days, the plantlets were randomly distributed on benches to evaluate the effects of 50 and 80% shading screens. Regardless of the clone, the commercial substrate and subsurface soil composition allowed plantlet production with satisfactory development of both aerial part and root system at 120 days of cultivation. Clone 06SM17 produced plantlets with high averages of stem diameter, shoot height, number of leaves, total length, surface area, total volume of roots, and number of root tips. Both shade levels resulted in similar stem diameters, shoot heights, numbers of leaves, and a, b, and total chlorophyll indices. Clonal mate plantlets with satisfactory morphophysiological quality are produced in commercial substrate and subsurface soil (2:1 v/v) under 50 and 80% shading.

A erva-mate (Ilex paraguariensis A. St.-Hil) é espécie arbórea de grande importância econômica e socioambiental para os países da América do Sul, que apresenta diversas dificuldades de propagação utilizando sementes, sendo os estudos relacionados à produção de mudas dessa espécie por propagação vegetativa fundamentais para a obtenção de ervais homogêneos e com alta produtividade foliar. Diante desse contexto, o presente estudo objetivou avaliar o efeito das composições de substratos e dos níveis de sombreamento na qualidade morfofisiológica das mudas de erva-mate produzidas por miniestaquia. Miniestacas enraizadas de quatro clones foram cultivadas em substrato comercial, solo de subsolo e vermiculita (2:1:1 v/v/v), substrato comercial e solo de subsolo (2:1 v/v) ou solo de subsolo, esterco bovino e casca de arroz carbonizada (2:1:1 v/v/v). Após 120 dias, as mudas foram aleatoriamente distribuídas em bancadas para avaliar o efeito do sombreamento de 50 e 80%. Independentemente do clone, a composição substrato comercial e solo de subsolo permitiu a produção de mudas com desenvolvimento satisfatório tanto da parte aérea, quanto do sistema radicular aos 120 dias de cultivo. O clone 06SM17 possibilitou a produção de mudas com altas médias de diâmetros de colo, altura da parte aérea, número de folhas, comprimento total, área superficial, volume total de raízes e número de extremidades das raízes. Os níveis de sombreamento não afetaram o diâmetro de colo, a altura da parte aérea, o número de folhas e os índices de clorofila a, b e total. Mudas clonais de erva-mate com satisfatória qualidade morfofisiológica podem ser produzidas em substrato comercial e solo de subsolo (2:1 v/v) em ambiente com 50% ou 80% sombreamento.

Distribution update, conservation status and color in life of the rare Amazonian snake, Eutrachelophis papilio Zaher and Prudente 2019 (Serpentes: Xenodontini)

The rare Amazonian snake Eutrachelophis papilio is known from only five individuals, from four localities, belonging to its type-series, the more recent collected over 10 years ago. Here, we expand its distribution and describe its color in life for the first time. We also provide an estimate of its distribution area using the minimum convex polygon method and identify the values of anthropic pressure within its known distribution range with the Human Footprint Index. The new occurrence is located 291 km from the nearest known locality and its distribution is associated with pristine forests. Considering its rarity, and the absence of demographic and biological data, we suggest that the species should be classified as Data Deficient by IUCN criteria. (AU)

Subcellular Proteomics in Conifers: Purification of Nuclei and Chloroplast Proteomes.

The complexity of the plant cell proteome, exhibiting thousands of proteins whose abundance varies in several orders of magnitude, makes impossible to cover most of the plant proteins using standard shotgun-based approaches. Despite this general description of plant proteomes, the complexity is not a big issue (current protocols and instrumentation allow for the identification of several thousand proteins per injection), low or medium abundant proteins cannot be detected most of times, being necessary to fraction or perform targeted analyses in order to detect and quantify them. Among fractioning choices, cell fractioning in its different organelles is a good strategy for gaining not only a deeper coverage of the proteome but also the basis for understanding organelle function, protein dynamics, and trafficking within the cell, as nuclear and chloroplast communication. This approach is used routinely in many labs working with model species; however, the available protocols focusing on tree species are scarce. In this chapter, we provide a simple but robust protocol for isolating nuclei and chloroplasts in pine needles that is fully compatible with later mass spectrometry-based proteome analysis.

Ceratopogonidae (Diptera) Communities in a Protected Area Threatened by Urbanization.

This study highlights the species diversity of Ceratopogonidae from the Paranaense forest and adjacent grassland in a protected natural area of Argentina, and emphasizes the importance of conserving the last remaining marginal forest area surrounded by a strong urbanization. A total 46 species belonging to 10 genera were recorded from these two habitats. Species diversity was higher in the grassland, while dominance was greater in the forest. Twelve species were abundant, while the rest were scarce or rare. The composition of the ceratopogonid community differs between habitats: 15 species were exclusive to the forest, 4 to the grasslands, and 27 used both habitats indistinctly. Differences between habitats were observed in the abundances of Alluaudomyia schnacki Spinelli, Atrichopogon albinensis Ingram and Macfie, and Forcipomyia rioplatensis Marino and Spinelli. The sex ratio of the most abundant species did not show a definite pattern in relation to the habitats, except for Culicoides caridei (Brèthes), in which females were dominant. Atrichopogon balseiroi Spinelli and Forcipomyia williamsi Marino & Spinelli have only been recorded in Buenos Aires Province and were found exclusively in the forest during this study.

Phytoremediation by Eremanthus crotonoides and Inga striata decay atrazine and clomazone residues in the soil.

The atrazine and clomazone molecules have potential to contaminate environments, especially water resources. Phytoremediation decontamination can prevent or reduce the quantity of these products reaching watercourses. The objective was to evaluate the remedial potential and the physiological sensitivity of Eremanthus crotonoides (DC.) Sch. Bip and Inga striata Benth to atrazine and clomazone in soils contaminated with 0.0, 0.5, 1.0 and 2.0 times the recommended commercial dose of these herbicides. The photosynthesis, CO2 consumed stomatal conductance and transpiration of E. crotonoides and I. striata, in soils contaminated with atrazine and clomazone, were evaluated. The herbicide residues were detected by ultra-high performance liquid chromatography tandem mass spectrometry (UHPLC-MS/MS) 30 days after the last herbicide application. The photosynthesis rate and CO2 consumed by E. crotonoides and I. striata were lower in soils contaminated by atrazine and clomazone. Inga striata had lower stomatal conductance and transpiration in soil contaminated with clomazone. Eremanyhus crotonoides and I. striata reduced the residues of these herbicides. The atrazine and clomazone reduced the physiological variables of E. crotonoides and I. striata. These plants can be used to recover areas with residues of these herbicides, acting as filters that will decrease the amount of herbicides that would reach the watercourses.

Temperature and light under the physiological potential of seeds of Handroanthus impetiginosus / Temperatura e luz sob o potencial fisiologico de sementes de Handroanthus impetiginosus

H. impetiginosus belongs to the Bignoniaceae family; it has a great potential for economic exploitation and can be used in landscaping of urban areas, reforestation, recovery of degraded areas, and folk medicine. The experiment was carried out to evaluate the effect of light and temperature regimes on the germination and vigor of Handroanthus impetiginosus seeds at the Seed Analysis Laboratory of UFRPE/UAG. The seeds were subjected to light regimes: white, far red, red, and no light at 15°C, 20°C, 25°C, 30°C, 35°C, and 40°C, using a completely randomized experimental design in a factorial scheme (4 × 6), with four repetitions of 25 seeds. The different light regimes did not influence the seed germination of H. impetiginosus. The highest germination percentage (92%) and germination speed index (7.94) were obtained at temperatures 28.2°C and 29.2°C, respectively, both under red light. The longest seedling length was also obtained from the seeds subjected to red light regime at 25°C. The temperatures of 15°C and 40°C inhibited the germination of H. impetiginosus seeds. H. impetiginosus seeds are classified as neutral photoblastics, and constant temperatures of 28.2°C and 29.2°C provided maximum germination.

H. impetiginosus, pertencente à família Bignoniaceae, apresenta grande potencial para exploração econômica, podendo ser utilizado no paisagismo de áreas urbanas, reflorestamentos, recuperação de áreas degradadas e na medicina popular. O experimento foi conduzido no Laboratório de Análise de Sementes da UFRPE/UAG com o objetivo de avaliar o efeito dos regimes de luz e temperatura na germinação e vigor de sementes de Handroanthus impetiginosus. As sementes foram submetidas aos regimes de luz: branca, vermelho distante, vermelho e ausência de luz sob as temperaturas de 15, 20, 25, 30, 35 e 40°C, sendo utilizado o delineamento experimental inteiramente ao acaso, em esquema fatorial (4x6), com quatro repetições de 25 sementes. Os diferentes regimes de luz não influenciaram na germinação de sementes de H.impetiginosus. A maior porcentagem de germinação (92%) e índice de velocidade de germinação (7,94) foram obtidos nas temperaturas 28,2 e 29,2°C, respectivamente, ambos no regime de luz vermelha. O maior comprimento de plântula também foi obtido de sementes submetidas ao regime de luz vermelha na temperatura de 25ºC. As temperaturas de 15ºC e 40ºC inibiram a germinação das sementes de H. impetiginosus. As sementes de H. impetiginosus são classificadas como fotoblásticas neutras e as temperaturas constantes de 28,2 e 29,2°C proporcionaram máxima germinação.

[Community structure of Quercus aliena var acuteserrata forest in the Taibai Mountain, China].

Qinling Mountains are biodiversity hotspots in China, with rich vegetation resources and species diversity. To clarify the mechanism underlying biodiversity maintenance during vegetation restoration in this area, we established two permanent plots with each area of 100 m×150 m in the Q. aliena var. acuteserrata secondary forest (SF) and primary forest (PF) in the northern slope of Taibai Mountain in 2016, following the standardized protocols by CTFS (the Center for Tropical Forest Science). We analyzed community composition and structure with measuring all trees with DBH ≥ 1 cm. 2839 and 2840 trees were recorded in the SF and PF plots, respectively. Trees in those two plots belong to 29 families, 45 genera, 65 species and 21 families, 37 genera, 47 species, respectively. The proportions of occasional species and rare species were 38.4% and 24.6% in the SF plot, and 40.4% and 19.2% in the PF plot. Most of the trees were distributed in northern temperate zones, and the proportions of genera were 46.6% and 48.7% in the SF and PF plots, respectively. The diameter of Q. aliena var. acuteserrata in both plots followed a unimodal distribution (more young trees than old ones). The diameter distributions of companion species (e.g., Sorbus alnifolia, Acer davidii, Cornus kousa, and Staphylea holocarpa) were inverted "J" shapes, indicating that those populations could have complete life history. In the pair correlation function g(r) analyses, the aggregation of dominant species were the strongest at 0-2 m scale in the two plots when r=10 m. The degree of aggregation gradually weakened with increasing scale. The population distribution patterns of the dominant species were random or uniform when the scale increased to certain value. The average uniform angle index (W) were 0.56 and 0.58 in the SF and PF, respectively. Trees in the communities followed an aggregated distribution. The average W of the community and dominant species in the SF were smaller than that in the PF, indicating weaker species aggregation in the SF. The average dominance in the SF and PF was both 0.47, indicating that the stands were in a co-dominant state. The average mingling was 0.70 and 0.57 in the SF and PF, respectively, which belonged to high and moderate mingling. Species richness, community stability and spatial distribution patterns of forest community could be affected by human disturbance. The role of interspecific interaction, effects of habitat heterogeneity on species coexistence, and variation of community structure should be considered during vegetation restoration of disturbed forest community.

Seed vigor of Piptadenia moniliformis Benth. subjected to thermal stress

The objective of this work is to evaluate the influence of accelerated aging test at 41ºC on the germination and seed vigor of Piptadenia moniliformisBenth. Two experiments were conducted. Experiment 1: seeds were submitted to dormancy overcoming treatments. They were immersed into sulfuric acid for 0 (intact seeds), 5, 10, 15, 20 and 25 minutes. Experiment 2: two methods were evaluated for the accelerated aging test at 41ºC, that is, the traditional method and the saturated NaCl solution method with exposure periods of 0, 24, 48, 72 and 96 hours. After each treatment, the seeds were subjected to electrical conductivity and germination tests. Seeds overcame their dormancy when immersed into concentrated sulfuric acid for 5, 10, 15, 20 or 25 minutes, but thegermination was faster when immersed for 20 minutes. The different methods for the accelerated aging test, decreased the germination potential and seed vigor of P. moniliformisafter 24 hours of exposure. Regarding the method used, the saturated solution provided, in general, the best results since the seed water content was lower, thus reducing the proliferation of fungi. The electrical conductivity test showed that, by increasing the aging period regardless of the method, there is an increase in seed deterioration, corroborating with germination results, which showed that the correlation was moderate and negative and indicated that the higher the conductivity, the lower the percentage and the germination speed index. The immersion of seeds of P. moniliformisinto concentrated sulfuric acid for 20 minutes provides a fast and increased germination. The methods for accelerated agingat 41ºC, traditional and saturated solution, can be used as vigor tests to evaluate the physiological quality of seeds.

Saline soil reclamation by agroforestry species under Kalaât Landelous conditions and irrigation with treated wastewater in Tunisia.

Irrigation with treated waste water (TWW) in combination with plantation of agroforest species was tested in the Kalaât Landelous region for the reclamation of salt affected soils. Five species (Atriplex nummularia, Eucalyptus gomphocephala, Acacia cyanophylla, Casuarina glauca, Pinus halepensis) were cultivated in saline soils that are affected by shallow, saline groundwater and were irrigated with TWW during the summer season. The results after 4 years of experimentation show a distinct decrease in soil pH and salinity accompanied by a decrease in Cl and Na concentrations. Irrigation decreased the heavy metal concentrations in the topsoil but an increase in deeper layers indicate to leaching due to TWW irrigation. The investigated plant species were differently affected in growth performance by salinity and TWW irrigation. Atriplex nummularia appeared to be the most resistant species and Pinus halepensis the most sensitive one to hydro-pedological conditions of the Kalaât Landelous plot. In conclusion, salt-tolerant plant species seem to be good candidates for the reclamation of salt-affected, waterlogged sites in combination with TWW irrigation, as the adaptations of such species seem to operate under different abiotic stress conditions.

Epiedaphic Ground Beetle (Carabidae) Diversity in Ecosystems Transformed by Plantations of Eucalyptus pellita in the Orinoco Region of Colombia.

Patterns of land use are changing dramatically in the Orinoco region of Colombia, including extensive commercial forestation of Pinus caribaea, Acacia mangium, and Eucalyptus pellita that are replacing savannas, with unknown consequences for biodiversity. We studied the effects of E. pellita plantations on the diversity of epiedaphic carabid beetles (Carabidae) sampled with pitfall traps at El Vita (Vichada) and Villanueva (Casanare). Furthermore, we assessed stand structure data (basal area, and canopy cover), and soil physical and chemical properties to explain differences in ground beetle composition using redundancy analysis (RDA). We compared diversity and species turnover using Hill numbers and Bray-Curtis dissimilarity, respectively. Low differences in richness were observed between savannas and plantations (at El Vita) and between pastures and plantations (at Villanueva). In general, carabid richness was significantly (not overlap in 95% confidence intervals) higher during the rainy season, and in young plantations than in other habitats. Variation in carabid species composition was mainly explained by a gradient of volumetric humidity, number of trees, basal area at El Vita and pH, nitrogen content of the soil, number of trees, soil clay content, and area of exposed ground at Villanueva. Thirteen carabid (which eight are commons in natural forests) species were identified as indicators of 3- and 14-year-old E. pellita plantations and pastures. Results suggest a strong response of ground beetles (Carabidae) to changes in land use, seasonality, and plantation age. Further research is needed to better understand how landscape heterogeneity, and distance to contiguous of natural habitats, influences biodiversity.

Multi-Scenario Species Distribution Modeling.

Correlative species distribution models (SDMs) are increasingly being used to predict suitable insect habitats. There is also much criticism of prediction discrepancies among different SDMs for the same species and the lack of effective communication about SDM prediction uncertainty. In this paper, we undertook a factorial study to investigate the effects of various modeling components (species-training-datasets, predictor variables, dimension-reduction methods, and model types) on the accuracy of SDM predictions, with the aim of identifying sources of discrepancy and uncertainty. We found that model type was the major factor causing variation in species-distribution predictions among the various modeling components tested. We also found that different combinations of modeling components could significantly increase or decrease the performance of a model. This result indicated the importance of keeping modeling components constant for comparing a given SDM result. With all modeling components, constant, machine-learning models seem to outperform other model types. We also found that, on average, the Hierarchical Non-Linear Principal Components Analysis dimension-reduction method improved model performance more than other methods tested. We also found that the widely used confusion-matrix-based model-performance indices such as the area under the receiving operating characteristic curve (AUC), sensitivity, and Kappa do not necessarily help select the best model from a set of models if variation in performance is not large. To conclude, model result discrepancies do not necessarily suggest lack of robustness in correlative modeling as they can also occur due to inappropriate selection of modeling components. In addition, more research on model performance evaluation is required for developing robust and sensitive model evaluation methods. Undertaking multi-scenario species-distribution modeling, where possible, is likely to mitigate errors arising from inappropriate modeling components selection, and provide end users with better information on the resulting model prediction uncertainty.

Use of Frozen Leaves for Morpho-anatomical Characterization of Nectandra megapotamica (Spreng) Mez, Lauraceae

Abstract Nectandra megapotamica (Spreng.) Mez. it is a native tree species of the Atlantic Forest, commonly known as canela-preta. The species has some anti-inflammatory, antitumor and antirheumatic properties among others. In this work the use of frozen plant material for microscopy analysis was tested. In addition, the leaf morpho-anatomy of the species was characterized which allowed to perform a structural description and to identify structures of secretion and storage of essential oil. The plant material was prepared for analyzes in optical, fluorescence and scanning electron microscopy. The leaf anatomy shows glabrous epidermis, unistratified, paracytic stomata, absence of trichomes, polyhedral epidermal cells. Some typical family characteristics were observed as a closed arc-shaped bicollateral bundle vascular system and dorsiventral mesophyll. The structures of secretion and storage of essential oil were identified as secretory cavities.