Floristic Groups Research Articles

Landscape-scale processes influence riparian plant composition along a regulated river

Hierarchical frameworks are useful constructs when exploring landscape- and local-scale factors affecting patterns of vegetation in riparian areas. In drylands, which have steep environmental gradients and high habitat heterogeneity, landscape-scale variables, such as climate, can change rapidly along a river's course, affecting the relative influence of environmental variables at different scales. To assess how landscape-scale factors change the structure of riparian vegetation, we measured riparian vegetation composition along the Colorado River through Grand Canyon, determined which factors best explain observed changes, identified how richness and functional diversity vary, and described the implications of our results for river management. Cluster analysis identified three divergent floristic groups that are distributed longitudinally along the river. These groups were distributed along gradients of elevation, temperature and seasonal precipitation, but were not associated with annual precipitation or local-scale factors. Species richness and functional diversity decreased as a function of distance downstream showing that changing landscape-scale factors result in changes to ecosystem characteristics. Species composition and distribution remain closely linked to seasonal precipitation and temperature. These patterns in floristic composition in a semiarid system inform management and provide insights into potential future changes as a result of shifts in climate and changes in flow management.

Effects of vegetation patterns and environmental factors on woody regeneration in semi-arid oak-dominated forests of western Iran

This study assesses the effects of vegetation patterns and environmental factors on the abundance of natural tree and shrub regeneration in semi-arid forests of the Zagros Mountains, western Iran. We sampled 120 releves at different topographic positions in a protected area of the studied region. Floristic composition, slope, elevation and soil properties were recorded at each releve, and woody seedling density was measured. We have first discerned five floristic groups using two-way indicator species analysis (TWINSPAN), detrended correspondence analysis (DCA), and canonical correspondence analysis (CCA) and then explored the relationships among the floristic group compositions, environmental factors and seedling densities. The indicator species of the five groups were Quercus brantii, Acer monspessulanum, Cerasus microcarpa, Rhamnus arvensis and Astragalus licyoides. Our results indicated that these groups were significantly affected by elevation and soil properties and the soil properties refer to: EC (electrical conductivity), N (nitrogen), K (potassium), OM (organic matter), and bulk density. Woody regeneration was composed of Q. brantii, A. monspessulanum, C. microcarpa, Amygdalus scoparia and Crataegus pontica seedlings. The highest density of seedlings was found for Q. brantii (97.14 (±48.00) plants/hm2) and the lowest for A. scoparia (2.28 (±1.50) plants/hm2). Quercus brantii was the dominant species and the seedling density was positively correlated with soil pH and P (phosphorus) values. Amygdalus scoparia regeneration was negatively correlated with elevation, and the seedling density peaked in C. microcarpa group. There was no significant variation in distribution of C. pontica seedlings among the groups, but the seedling density of this species was positively correlated with slope and K. Cerasus microcarpa seedlings were more abundant in the Q. brantii group than in other groups. This study showed that the regeneration of tree and shrub species was unequally distributed in different floristic groups for some species (A. scoparia and C. microcarpa) but not for other (Q. brantii and C. pontica) and was generally correlated with some environmental factors, particularly elevation, slope and soil nutrients (P and K). These results are a first step to implement future management and restoration strategies for promoting forest regeneration.

Lack of floristic identity in campos rupestres—A hyperdiverse mosaic of rocky montane savannas in South America

The rocky montane savannas of South America, known as campos rupestres in Brazil, where they largely occur, represent a hyperdiverse habitat housing c.15% of the Brazilian vascular flora in less than 1% of the Brazilian territory. Amongst other factors, the remarkable plant diversity in campos rupestres has been attributed to its occurrence as many isolated patches and to floristic influences from surrounding habitats, including lowland woody savannas (cerrado), Atlantic rain forests, seasonally dry woodlands and Amazonian rain forests. However, no study has assessed the degree to which the putative floristic influence from surrounding habitats drives compositional variation in campos rupestres. Here, we used a dataset on the composition of South American woody plant communities (4,637 community surveys, with 115 representing campos rupestres), combined with environmental data, with the aim of characterising and explaining compositional variation of the campos rupestres woody flora. Our results showed that all campos rupestres, including the sites occurring in Amazonian ironstone formations, are more similar to cerrado woody savannas than to any other South American vegetation formations covered in our dataset. Also, multiple campo rupestre floristic groups may be recognized based on distinct species composition and environmental conditions, primarily related to substrate and climate. We stress the importance of considering this floristic heterogeneity in conservation, management and research planning.

Floristic composition of vegetation in habitats suitable for Erigeron × huelsenii (Asteraceae)

Abstract The paper provides data on the floristic composition of vegetation in anthropogenic habitats suitable for Erigeron × huelsenii, a spontaneous hybrid between the alien E. canadensis and native E. acris s. str. The study is based on 21 phytosociological relevés (vegetation plots) of 5×5 m size made in 2013-2014 in the Polish part of the Lithuanian Lakeland (north-eastern Poland) using the Braun-Blanquet method. The plots were taken on a roadside verge, a roadside slope, in abandoned sand and gravel pits, and on arable fields with grass-legume mixtures. There are 91 species of vascular plants, four species of bryophytes, three species of lichens, and one species of cyanobacteria. Vegetation is represented by populations of species typical of plant communities from the classes Stellarietea mediae, Artemisietea vulgaris, Koelerio-Corynephoretea, Festuco- Brometea and Molinio-Arrhenatheretea. Two floristic groups recognized from hierarchical cluster analysis and principal component analysis correspond with ruderal and segetal habitats. The study reveals that arable fields with grass-legume mixtures on sandy soils can be very suitable for E. × huelsenii.

Resolución nacional de especies amenazadas de Colombia

El 15 de septiembre del 2017, con la emisión de la Resolución 1912, se estableció el último listado de especies silvestres que se encuentran amenazadas a nivel continental y marino en el territorio nacional. Dicho acto administrativo categorizó a diferentes grupos faunísticos y florísticos en las categorías de Peligro crítico (CR), en Peligro (EN) y Vulnerable (VU) basado, según se indica en dicho documento, en los criterios, subcriterios y umbrales propuestos por la UICN. Sin embargo, la publicación de dicha resolución plantea numerosos cuestionamientos para múltiples grupos, en especial los mamíferos, lo que pone en tela de juicio la utilidad de este acto para la conservación de la biodiversidad.

DINÂMICA DA CHUVA DE SEMENTES EM REMANESCENTE DE FLORESTA ESTACIONAL SUBTROPICAL

O presente estudo teve por objetivo avaliar a dinâmica da chuva de sementes em dois agrupamentos florísticos formados em um remanescente de Floresta Estacional Subtropical. Os agrupamentos foram caracterizados pelo estágio sucessional da floresta, denominados de grupo I (Floresta Secundária em Estágio Médio - FSEM), com predomínio de espécies secundárias iniciais; e o grupo II (Floresta Secundária em Estágio Avançado - FSEA), com predomínio de espécies secundárias tardias. A chuva de sementes (CS) foi avaliada em 70 coletores de 1 m², distribuídos de forma aleatória nos dois agrupamentos, sendo que no grupo I foram instalados 15 coletores e no grupo II, por apresentar maior área, 55 coletores. O material depositado foi coletado mensalmente, no período de outubro de 2008 a outubro de 2010. A dinâmica da CS foi avaliada pela densidade de sementes de cada espécie, síndrome de dispersão e sazonalidade da produção. Utilizou-se o teste não paramétrico da Soma das Ordens de Wilcoxon (W) para verificar diferenças estatísticas nas médias de densidade de sementes em cada ano de avaliação para cada trecho de floresta. A chuva de sementes do remanescente estudado, durante os três anos de estudo, foi representada por 114 espécies e a maior produção de sementes ocorreu em 2008 (1632 sem.m-² no grupo I e 1270 sem.m-² no grupo II), principalmente devido à ocorrência da alta produção de Chusquea ramosissima Lindm., Dasyphyllum spinescens (Less.) Cabrera, Vernonanthura discolor (Spreng.) H.Rob. Somente no segundo ano (2009) observaram-se diferenças estatísticas nas médias de densidade entre os dois grupos analisados (FSEM=565,6 sem.m-2 e FSEA=274 sem.m-2; Z tabelado =1,96 e W FSEM x FSEA = 2,248). As espécies zoocóricas predominaram na área de estudo, e os períodos de maior produção de sementes foram o inverno e a primavera. A CS mostrou-se importante mecanismo de regeneração natural para o remanescente de floresta, sendo afetado pelas condições climáticas e estágio sucessional da floresta.

Variações na composição e estrutura da vegetação permitem detectar agrupamentos florísticos em uma Floresta Subtropical Atlântica no Sul do Brasil?

http://dx.doi.org/10.5007/2175-7925.2016v29n4p43As variações da vegetação em função da posição topográfica têm despertado o interesse dos pesquisadores. Entretanto, poucos estudos verificaram as associações florísticas formadas pela posição topográfica de uma encosta. Neste trabalho, analisamos se as variações na vegetação permitem detectar agrupamentos florísticos em uma Floresta Pluvial Subtropical. A vegetação foi amostrada em 25 parcelas de 400 m² distribuídas sistematicamente, onde foram medidos os indivíduos com DAP ≥ 5,0 cm. Amostramos 1.727 indivíduos e 144 espécies. A ordenação NMDS segregou três grupos em função da posição topográfica da encosta (Monte Carlo, P ≥ 0,05; ANOSIM, P < 0,001). Euterpe edulis e Sloanea guianensis se destacaram nos terços inferior e médio da encosta, enquanto Ocotea aciphylla e Alchornea triplinervia se destacaram no terço superior. Algumas espécies se mostraram indicadoras dos setores analisados, como é o caso de Actinostemon concolor e Alsophila setosa no terço inferior, Cyathea corcovadensis e Rudgea recurva no terço médio e Myrcia pulchra e Podocarpus sellowii no terço superior. Nossos resultados indicaram que as variações florísticas e estruturais observadas por Veloso e Klein (1959) e Klein (1980; 1984) para o Vale do Itajaí em Santa Catarina apresentam validade estatística nos dias atuais, pois verificamos a formação de diferentes grupos de acordo com a posição topográfica da encosta.

Ferns and lycophytes in three fragments of Tabuleiro lowland forest in northern Espírito Santo State, Brazil: composition and floristic relationships in Atlantic forest

We present here the fern and lycophyte species found in three areas of Atlantic Forest with lowland forest physiognomies, in northern Espirito Santo State, Brazil, and compare their floristic relationships with other physiognomies of that biome in the state. We recorded 57 species, distributed among 35 genera and 18 families within the Corrego Grande Biological Reserve, Rio Preto National Forest, and the Corrego do Veado Biological Reserve. The most representative families were Pteridaceae (17 spp.) and Polypodiaceae (eight spp.), while the genus Adiantum demonstrated the greatest species richness (eight spp.). The fern and lycophyte floras differed significantly between the different Atlantic Forest physiognomies, with indicator species identified for each, as well as species that occur preferentially in certain physiognomies. Correspondence analysis and grouping analysis employing relative Sorensen distances indicated the existence of four floristic groups associated with the different Atlantic Forest physiognomic types related to altitudinal gradients. Greater similarities were found between the floras of the same physiognomies, with the greatest consistency and floristic homogeneity being seen among regions below 300 m, principally the Tabuleiro lowland forests in the northern region of the state.

FLORISTIC-STRUCTURAL CHARACTERIZATION AND SUCCESSIONAL GROUP OF TREE SPECIES IN THE CERRADO BIOME OF TOCANTINS STATE, BRAZIL

ABSTRACT: The objective of this study was to characterize the floristic composition, vegetation structure and ecological group of tree species in a cerradão forest (Cerrado biome) of Palmas, Tocantins State, Brazil. A forest inventory was performed in an area of 10.15 hectares, using systematic sampling with plots of 400 m², in which all standing trees, alive and dead, that had diameter at breast height (DBH) ≥ 5 cm were sampled and identified. A linear plateau regression model (LPR) was used for sample sufficiency analysis. The Shannon index (H') was used for assess the floristic diversity, and the Importance Value Index (IVI) for assess the horizontal structure. The forest was classified in three strata according to vertical structure analysis. The LPR showed that the sampling size was adequate. The predominate species in the area were Myrcia splendens, Emmotum nitens and Qualea parviflora, and species from the families Fabaceae and Chrysobalanaceae. The pioneer (613 individuals ha-1) and climax (530 individuals ha-1) species were the predominating groups. Regarding the richness index, the number of climax (57 species) and pioneer (25 species) species stood out. The alpha floristic diversity was 3.35 nats individuals-1 and the Pielou equability value J = 0.76. The diametric distribution showed a negative and balanced exponential pattern. Regarding the vertical stratification, the smallest amount of individuals was in the upper stratum (13%) and the highest in the mid stratum (63%) and in the lower stratum (24%). The use of floristic composition tools with horizontal and vertical structure analysis was effective for understand the tree community, which may be considered structured and diverse, thus able to restructure possible disturbances when preserved.

Forest Structure and Community Composition of Cochin Mangroves, South-West Coast of India

This study presents the structural characteristics of Cochin mangroves in Kerala for proposing suitable management and rejuvenation measures of degrading mangrove habitats. The floristic diversity of mangroves revealed 14 species of true mangroves belonging to six families. Multivariate analysis of true mangroves belonging to selected mangrove forests of the study area based on density could be classified into four floristic groups, a water front or low–tide zonation, mid-tide preferring species, high tide and landward zonation. Shannon Weiner index of the three stations revealed that Site I was having higher value (H′ = 2.66) followed by Site II (H′ = 2.01) and Site III (H′ = 1.595). The density of the mangroves varied significantly with sites and species (Global R = 0.537, P < 0.001). The diameter at breast height (DBH) in the study area revealed that most of the species came under 1–10 cm DBH class. The overall structural data (including Importance Value Index, DBH and basal area) showed that Site III, the Mangalavanam forest was having more structural development and could be considered as matured forest whereas, Site I, Aroor is a maturing forest and Site II, Malippuram is the least matured forest from the study. The Importance Value Index and basal area of each species could be used for analysing the maturity of the forest and habitat preferences for restoration programmes of the degraded ecosystems.

A Phytogeographical Metaanalysis of the Semiarid Caatinga Domain in Brazil

Seasonally Dry Tropical Plant Formations (SDTFs) are among the most threatened biomes worldwide. Nevertheless, they have received less scientific attention than rainforests or savannas. One such SDTF, the Caatinga Phytogeographic Domain (CPD), is the largest semiarid tropical ecoregion in South America. Earlier floristic studies of the Caatinga flora discerned two floristic groups in the CPD, in terrains of crystalline and sedimentary origin respectively. We compiled and analysed the most comprehensive dataset on CPD plant distributions to produce a general biogeographical synthesis for Caatinga, including inselbergs, riverine forests and ecotonal areas. Not only are crystalline and sedimentary caatingas clearly distinct, but inselbergs collectively form a third floristic group in the CPD. Non-woody plants, omitted from many studies, are a major component of Caatinga diversity, comprising more than 60 % of species in some local communities. Raunkiaerian life-form spectra of Caatinga sites show that Caatinga vegetation differs in life-form spectra from those of major world biomes, supporting recognition of SDTFs as a discrete world biome.

Do water requirements of Mediterranean gardens relate to socio-economic and demographic factors?

Gardeners can consume a large proportion of total domestic water, depending on their garden type and gardening style. We calculated water requirements of gardens based on species composition and land cover, and determined whether they can be predicted from the socio-economic, demographic and cultural characteristics of households. We recorded the plant species composition, garden cover types, and household characteristics of 258 households in suburbs of the Mediterranean coast of Catalonia. The distribution of the 635 species in these gardens were the input to a cluster analysis, in which semi-natural gardens, vegetable gardens, lawn gardens and ornamental gardens formed strong floristic groups, with ornamental gardens predicted to require the least water inputs and lawn gardens the most. We conclude that only income and a lack of work were related to our water requirement variable, reflecting the expense of water and the propensity of the retired to spend more time in the garden.

The enhancement of invasion ability of an annual grass by its fungal endophyte depends on recipient community structure

Most terrestrial plants establish symbiotic associations with microorganisms that enable them to overcome abiotic or biotic filters in ecosystems. Here we investigated how aerial mutualisms involving invasive species may affect the recipient community’s structure. We hypothesized that the endophyte Epichloe occultans enhances the ability of Lolium multiflorum to establish and colonize, but that success would depend on the structure and invasion resistance of the recipient grassland community. Seeds of L. multiflorum with high (E+) and low (E−) endophyte incidence were sown in plots located in grasslands with or without recent grazing history. Relative cover of L. multiflorum and floristic groups was determined during the growing season. Whereas we did not detect any endophyte effect in sites with grazing history, L. multiflorum cover was 63 % in E+ and 27 % in E− plots in sites without grazing history. As cover of L. multiflorum increased in these sites, the cover of warm- and cool-season grasses decreased in spring, with that of warm-season grasses continuing to decrease in summer. These decreases corresponded to 1.9, 3.7 and 1.6 %, for every % increase of L. multiflorum cover. Path analysis and posterior modelling predicted a greater impact of the endophyte on L. multiflorum cover than of seed addition when resident L. multiflorum cover was ≤20 %. This effect decreased asymptotically as L. multiflorum cover increased beyond 20 %. Our results suggest that the endophyte may boost the invasion ability of L. multiflorum particularly in natural grassland without grazing history with potential longer-term consequences for community structure and dynamics.

Communautés végétales des dunes mobiles de la frange septentrionale et de la région orientale du Maroc

The present work focuses on the study of the ecological structure of the spatial distribution of floristic settlement of the mobile dunes on the northern and eastern regions of Morocco. This study is spread over 400km ² from Guercif dunes in the north to the large Merzouga dunes in the Sahara, with various sites in between : northeast of Missour, Midelt, Aïn Beni Mathar, Tendrara, Rich, Bouârfa, Boudnib and Erfoud. In the 12 stations studied, we identified 41 plant species in 38 genera and 11 families. We found for the second time in Morocco Dactyloctenium aegyptium (L.) Willd. and Onopordon algeriense (Munby) Pomel. in Figuig. The greater plant richness is in the sites of Figuig and Tendrara (13 taxa each). Merzouga site only has six taxa. A Correspondence Analysis run on vegetation data allowed us to identify a north-south geographical gradient. Three major floristic groups were observed. The first is formed by the northern sites (Guercif, NE of Missour, Midelt and Aïn Beni

Regeneração natural de espécies arbóreas em diferentes comunidades de um remanescente de floresta ombrófila mista

A diversidade de ambientes encontrados em florestas naturais pode influenciar na regeneração natural e futuramente na dinâmica sucessional. Nesse contexto, objetivou-se avaliar a regeneração natural de espécies arbóreas em diferentes comunidades (grupos florísticos) de uma Floresta Ombrófila Mista. Foram amostradas 69 parcelas com dimensões de 10m x 10m, onde foram medidos os indivíduos com 3,0cm ≤ circunferência à altura do peito (CAP) &gt;30,0cm. Em subparcelas de 3,16m x 3,16m, foram medidos os indivíduos com CAP &gt;3,0cm e altura ≥50cm. As espécies com maior potencial de regeneração natural nas comunidades avaliadas foram Sebastiania brasiliensis e Stillingia oppositifolia (Grupo 1), Myrceugenia cucullata e Allophylus guaraniticus (Grupo 2) e Stillingia oppositifolia e Myrceugenia miersiana (Grupo 3). Destaca-se que as espécies Allophylus edulis, Blepharocalyx salicifolius, Justicia sp., Myrceugenia cucullata e Stillingia oppositifolia estiveram entre as 10 principais espécies nas três comunidades, mostrando elevado potencial de regeneração. As três comunidades favoreceram a ocorrência de elevada riqueza de espécies (Grupo 1=101; Grupo 2=98; Grupo 3=101). Todavia, as espécies secundárias tardias e secundárias iniciais mostraram maior adaptação aos diferentes locais da floresta, com densidade superior às espécies pioneiras.

Geographical patterns of terrestrial herbs: a new component in planning the conservation of the Brazilian Atlantic Forest

The Brazilian Atlantic Forest (sensu lato) is constituted by Dense Ombrophilous Forest, Mixed Ombrophilous Forest and Seasonal Semideciduous Forest, in which tree species are distributed in gradients, whichever latitude, longitude, or altitude is considered. We investigated whether herb species living on the floor of these forests would have the same geographic distribution pattern. If tree and herb-layer species have coincident distribution patterns, the same conservation units can conserve both species sets; otherwise, specific conservation actions should be taken. We built a presence/absence matrix of 803 terrestrial native species in 80 surveys across the southern and southeastern Brazilian Atlantic Forest. We performed UPGMA, CA and RDA multivariate analyses in order to investigate the distribution patterns. The high degree of agreement among the analyses led us to assume that the geographic distribution of the herb-layer flora occurs as gradients among three main floristic groups: Tropical Ombrophilous forests (mostly lowland forests), Subtropical Ombrophilous forests (mostly montane and upper-montane forests in lower latitudes and sub-montane and lowland forests in higher latitudes, i.e., where temperature is lower), and Seasonal Semideciduous forests (with a marked dry season). Based on different patterns and processes between herbs and trees, and in order to encompass the highest flora diversity, we highlight the importance of creating more reserves in each one of the three main floristic groups of herb-layer species in the Brazilian Atlantic Forest.

ESTRUTURA, DIVERSIDADE E HETEROGENEIDADE DO ESTRATO REGENERANTE EM UM FRAGMENTO FLORESTAL URBANO APÓS 10 ANOS DE SUCESSÃO FLORESTAL

Este estudo visou avaliar a composição florística, a fitossociologia e a diversidade de espécies do estrato regenerante arbóreo de um pequeno fragmento (0,5 ha) de Floresta Estacional Semidecidual, após 10 anos de abandono, no perímetro urbano do município de Juiz de Fora, MG, Brasil. Os indivíduos da regeneração arbórea (altura ≥ 1 m e DAP &lt; 5 cm) foram amostrados em 25 parcelas aleatórias de 5 x 5 m. Foram amostrados 1224 indivíduos pertencentes a 40 espécies. Houve uma forte predominância (&gt; 90%) de espécies de estágios sucessionais iniciais (pioneiras e secundárias iniciais). Como reflexo da forte dominância ecológica observada, exercida principalmente pela elevada densidade das espécies Dalbergia nigra e Siparuna guianensis, o valor do índice de diversidade de espécies de Shannon (H’ = 2,38) foi muito inferior aos valores encontrados para fragmentos florestais maduros. Mesmo sendo um fragmento pequeno, isolado e em estágio inicial de sucessão secundária, análises multivariadas (agrupamento e DCA) evidenciaram a formação de grupos florísticos e uma forte diferenciação no arranjo das espécies, evidenciando a heterogeneidade típica de florestas tropicais. Embora apresente uma baixa diversidade, esse fragmento urbano tem funções ecológicas e sociais importantes para a região, que carece de áreas verdes para a conservação da flora nativa.AbstractStructure, diversity and heterogeneity of regeneration stratum in an urban forest fragment after 10 years of forest succession. This research aimed to evaluate the floristic composition, phytosociology and species diversity of the regenerating woody stratum of a small fragment (0.5 ha) of Semideciduous Forest, after 10 years of abandonment, in the municipality of Juiz de Fora, MG, Brazil. All woody individuals (height ≥ 1 m dbh &lt;5 cm) were sampled at 25 random plots of 5 x 5 m. We sampled 1224 individuals belonging to 40 species. There was a strong predominance (&gt; 90%) of species of early successional stages (pioneer and early secondary). Reflecting the strong observed ecological dominance, exercised primarily by the high density of the species Dalbergia nigra and Siparuna guianensis, species diversity value (Shannon index H '= 2.38) was much lower than the values found for mature forest fragments in this region. Although a small fragment, isolated and in early stages of secondary succession, the multivariate analysis (cluster and DCA) revealed the formation of distinct floristic groups and a strong differentiation in the arrangement of the species, showing the tropical forests typical heterogeneity. Although it has a low diversity, this urban fragment has ecological and social importance to the region, that present lack of green areas to conserve the native flora.Keywords: Phytosociology; multivariate analysis; gradient analysis; ecological groups.

Multi-scale analysis of environmental constraints on macrophyte distribution, floristic groups and plant diversity in the Lower Paraná River floodplain

The Paraná River floodplain comprises one of the largest wetland systems of South America. In a sector of the Lower Paraná River floodplain (100km length, 3650km2), floristic composition and species diversity was characterized in 88 sites surveyed during summers 2010–11 and 2011–12. Hierarchical and fuzzy classifications were used to construct 26 floristic groups and 8 associations of floristic groups, and their indicator species were identified. A number of 124 species was distributed with a zonation pattern conforming marshes, salt marshes, wet prairies, bunchgrasses, grasslands and scrublands. We assessed how vegetation is affected by four nested levels of environmental constraints, representing a gradient from a landscape to a local scale, and including hydrological, geomorphological, topographic and edaphic variables. Species richness differed within categories of broad-scale landscape units (level 1) and within topographic positions (level 3). Also, 30 plant species, six floristic groups and five associations of groups responded to levels 1–3. The first two axes of a constrained Outlying Mean Index ordination accounted for 60% of the marginality of 61 common species as a function of soil features and flood frequency (level 4). Thus, the distribution of seven species showed significant marginality in association to soil electrical conductivity, soil silt percent and soil total nitrogen concentration. Multi-scale environmental constraints determined vegetation zones, and emerging floristic and diversity patterns. The multi-scale approach significantly improves the understanding of floristic patterns and plant biodiversity in the study area, and may be extended to other floodplain wetlands.

Análise de agrupamento florístico de Floresta Ombrófila Mista emSistema Faxinal

Abstract This study aimed to generate floristic groups of trees in a fragment of Araucaria forest and determine the floristic associations and evaluate the horizontal structure and the floristic diversity of each formed group. The data were obtained from an experiment implemented in Faxinal Marmeleiros de Baixo locality in Reboucas - Parana. In an area of 509 ha, were installed 50 permanent sample plots of 500 m² (10 mx 50 m), distributed in a systematic way, where each individual tree with DBH less than 10 cm was measured and identified. Using multivariate analysis, the sample units with similarity in diversity indices for its species were grouped using cluster analysis. We obtained two floristic groups: Group 1, involving 38 sample units representing 64% of the area; Group 2, with 12 sample units representing 36% of the area. Through to sociological analysis were identified the species with the highest VI in each group, which were Curitiba prismatic (Group 1), Campomanesia xanthocarpa (Group 2). Group 1, present high number of species and most dominant, while group 2 has a higher species richness and most divercidade.

Crescimento inicial do amendoinzeiro BR1 irrigado com água salina

This study aimed to generate floristic groups of trees in a fragment of Araucaria forest and determine the floristic associations and evaluate the horizontal structure and the floristic diversity of each formed group. The data were obtained from an experiment implemented in Faxinal Marmeleiros de Baixo locality in Rebouças - Parana. In an area of 509 ha, were installed 50 permanent sample plots of 500 m² (10 mx 50 m), distributed in a systematic way, where each individual tree with DBH less than 10 cm was measured and identified. Using multivariate analysis, the sample units with similarity in diversity indices for its species were grouped using cluster analysis. We obtained two floristic groups: Group 1, involving 38 sample units representing 64% of the area; Group 2, with 12 sample units representing 36% of the area. Through to sociological analysis were identified the species with the highest VI in each group, which were Curitiba prismatic (Group 1), Campomanesia xanthocarpa (Group 2). Group 1, present high number of species and most dominant, while group 2 has a higher species richness and most divercidade.