RESUMO
The high-elevation peatlands of the páramos of the northern Andes constitute a diverse environment that harbors large numbers of species and several types of plant communities along altitudinal, latitudinal, and environmental gradients. However, little is known about the structure and functioning of these ecosystems, including peatland vegetation types and their relative contribution to the production and accumulation of peat soils. In this paper we characterized the structure of peatland plant communities of the humid páramos of northern Ecuador by describing the distribution of plant growth-forms and their aboveground biomass patterns. Along an elevation gradient of 640 m we sampled vegetation in 16 peatlands and aboveground biomass in four peatlands. Three distinct peatland vegetation types were identified: High elevation Cushion peatlands, dominated by Plantago rigida and Distichia muscoides, Sedge and rush peatlands dominated by Carex spp. and Juncus spp., and Herbaceous and shrubby peatlands, with a more heterogenous and structurally complex vegetation. In terms of aboveground biomass, we found an 8-fold reduction in the higher peatlands compared to the lower sites, suggesting that the steep elevational gradients characteristic of Andean environments might be crucial in structuring the physiognomy and composition of peatland vegetation, either through its effects on temperature and other environmental factors, or through its effects on the age and development of soils. Additional studies are needed to evaluate the potential effects of temperature, hydrology, micro-topography, geological setting, and land-use, which are likely to influence vegetation patters in these peatlands.
RESUMO
Environmental heterogeneity is a key component in explaining the megadiversity of tropical forests. Despite its importance, knowledge about local drivers of environmental heterogeneity remains a challenge for ecologists. In Neotropical forests, epiphytic tank bromeliads store large amounts of water and nutrients in the tree canopy, and their tank overflow may create nutrient-rich patches in the soil. However, the effects of this nutrient flux on environmental heterogeneity and plant community structure in the understory remain unexplored. In a Brazilian coastal sandy forest, we investigated the effects of the presence of epiphytic tank bromeliads on throughfall chemistry, soil chemistry, soil litter biomass, light, and seedling community structure. In the presence of epiphytic tank bromeliads, the throughfall nitrogen concentration increased twofold, the throughfall phosphorus concentration increased threefold, and the soil patches had a 3.96% higher pH, a 50% higher calcium concentration, and 11.88% less light. By altering the availability of soil resources and conditions, the presence of bromeliads partially shifted the available niche spaces for plant species and indirectly affected the structure of the seedling communities, decreasing their diversity, density, and biomass. For the first time, we showed that the presence of tank bromeliads in the canopy can create characteristic soil patches in the understory, affecting the structure of seedling communities via fertilization. Our results reveal a novel local driver of environmental heterogeneity, reinforcing and expanding the key role of tank bromeliads both in nutrient cycling and plant community structuring of Neotropical coastal sandy forests.
Assuntos
Plântula , Solo , Florestas , Fósforo , Solo/química , ÁrvoresRESUMO
Tropical forests are important to the regulation of climate and the maintenance of biodiversity on Earth. However, these ecosystems are threatened by climate change, as temperatures rise and droughts' frequency and duration increase. Xylem anatomical traits are an essential component in understanding and predicting forest responses to changes in water availability. We calculated the community-weighted means and variances of xylem anatomical traits of hydraulic and structural importance (plot-level trait values weighted by species abundance) to assess their linkages to local adaptation and community assembly in response to varying soil water conditions in an environmentally diverse Brazilian Atlantic Forest habitat. Scaling approaches revealed community-level tradeoffs in xylem traits not observed at the species level. Towards drier sites, xylem structural reinforcement and integration balanced against hydraulic efficiency and capacitance xylem traits, leading to changes in plant community diversity. We show how general community assembly rules are reflected in persistent fiber-parenchyma and xylem hydraulic tradeoffs. Trait variation across a moisture gradient is larger between species than within species and is realized mainly through changes in species composition and abundance, suggesting habitat specialization. Modeling efforts to predict tropical forest diversity and drought sensitivity may benefit from adding hydraulic architecture traits into the analysis.
Assuntos
Secas , Árvores , Ecossistema , Florestas , Folhas de Planta , Árvores/fisiologia , Clima Tropical , Água , Xilema/fisiologiaRESUMO
Here, we investigated the relationship between Plant communities and the environment from the moist temperate vegetation of Lakoo mountainous forest District Swat. We sampled data from 162 sampling units (Quadrates) using 1x1m2 for herbs 5x5m2 and shrubs, while 10 x10m2 for trees, systematically considering six elevation gradients between the altitudinal from 1970m to 3095m. We performed statistical analysis like Canonical correspondence analysis (CCA) and TWINSPAN (two-way indicator species analysis) for ecological assessment and clustering of plant communities. To check upon the correlation of species (CR) with topographic and edaphic variables we used statistical software PC-ORD version 7. We recognized 264 species plants belonging to thirty families. We recorded key sampling measurements of density, frequency, and cover for all these species which are vital for community description. The results showed Shannon-Winner,s, and Simpson diversity values as 19.18 and 3.17 respectively. The importance value indexes (IVI) were used to identify the leading and rare species of plant in each community or cluster group. In total we recognized eleven different communities as: Berberis- Abies- Bergeni, Picea - Indigofera- Poa,Abies- Parrotiopsis- Poa, Quercus- Viburnum- Poa, Picea- Salix- Primula, Abies- Viburnum- Poa, Viburnum- Taxus- Poa, Pinus- Viburnum- Lithospermum, Abies-Berberis- carex, Pinus- Viburnum- Poa and Parrotiopsis- Picea- Poa through hierarchical cluster analysis (TWINSPAN). CCA analysis revealed that of all studied edaphic and topographic variables altitude, silt, calcium carbonate, and organic matter were the strongest factors determining plant community diversity and composition in each microclimate of the eleven communities. Visually the vegetation of the forest was dominated by small-sized trees followed by shrubs, and regenerates indicating the stage of secondary regeneration. We found severe human interference in disturbing the existing biodiversity, which requires immediate conservation to ensure sustainable management and utilization of natural resources of the Lalkoo moist temperate forest.
Aqui, investigamos a relação entre as comunidades vegetais e o meio ambiente da vegetação temperada úmida da floresta montanhosa de Lalkoo, distrito de Swat. Foram amostrados dados de 162 unidades amostrais (quadrados) utilizando 1 x 1 m2 para ervas, 5 x 5 m2 para arbustos e 10 x 10 m2 para árvores, considerando sistematicamente seis gradientes de altitude entre 1.970 m e 3.095 m. Realizamos análises estatísticas, como análise de correspondência canônica (CCA) e TWINSPAN (análise de espécies indicadoras de duas vias), para avaliação ecológica e agrupamento de comunidades de plantas. Para verificar a correlação das espécies (CR) com as variáveis topográficas e edáficas, foi utilizado o software estatístico PC-ORD, versão 7. Foram reconhecidas 264 espécies de plantas pertencentes a 30 famílias. Registramos as principais medições de amostragem de densidade, frequência e cobertura para todas essas espécies que são vitais para a descrição da comunidade. Os resultados mostraram valores de diversidade de Shannon-Wiener e Simpson de 19,18 e 3,17, respectivamente. Os índices de valor de importância (IVI) foram usados para identificar as espécies de plantas principais e raras em cada comunidade ou grupo de cluster. No total, reconhecemos 11 comunidades diferentes, como: Berberis-Abies-Bergeni, Picea-Indigofera-Poa, Abies-Parrotiopsis-Poa, Quercus-Viburnum-Poa, Picea-Salix-Primula, Abies-Viburnum-Poa, Viburnum-Taxus-Poa, Pinus-Viburnum-Lithospermum, Abies-Berberis-Carex, Pinus-Viburnum-Poa e Parrotiopsis-Picea-Poa, por meio de análise de agrupamento hierárquico (TWINSPAN). A análise de CCA revelou que, de todas as variáveis edáficas e topográficas estudadas, altitude, silte, carbonato de cálcio e matéria orgânica foram os fatores mais fortes na determinação da diversidade e composição da comunidade vegetal em cada microclima das 11 comunidades. Visualmente a vegetação da floresta foi dominada por árvores de pequeno porte, seguidas de arbustos, e se regenera, indicando o estágio de regeneração secundária. Encontramos grave interferência humana na biodiversidade existente, o que requer conservação imediata para garantir o manejo sustentável e a utilização dos recursos naturais da floresta temperada úmida de Lalkoo.
Assuntos
Biota , Floresta Úmida , PaquistãoRESUMO
This study investigated the effects of spatial and environmental factors and their interactions on plant species composition in salt marsh (Sabkha) ecosystem located in arid region (Saudi Arabia). The plant species and environmental variables were investigated in 38 sites located in three regions. A total of 15 environmental variables were measured in each site and the geographical coordinates were used to extract spatial variables (using PCNM). A total of 81plant species were reported from 38 sites. The three regions showed patterns of homogeneity of multivariate dispersions (i.e. beta diversity). The PCNM analysis extracted 18 PCNM vectors and only 3 vectors were retained after forward selection. The spatial variables (selected PCNM vectors) explained only 3.21% of the variation in species composition of plants (using variation partitioning technique). However, eight environmental variables were selected after forward selection (Lead, Copper, total organic matter, Potassium, Magnesium, pH, Zinc and Iron, F= 4.72, P<0.05) and explained 19.61% of the total variation in the species composition. In conclusion, the plant communities in Sabkhas were not spatially structured due to the low percentage of variation explained by the spatial variables (PCNM vectors). The environmental variables were corresponded to the high fraction of variation explained. On the other hand, Sabkhas in Saudi Arabia are considered a hot spot for diversity not only for plants but for other animals (birds, vertebrates and invertebrates). Therefore, immediate conservation plans should be implemented to reduce the adverse effect of urbanization, industrialization as well as other anthropogenic activities.
Este estudo investigou os efeitos de fatores espaciais e ambientais e suas interações na composição de espécies vegetais no ecossistema de sapal (Sabkha) localizado na região árida (Arábia Saudita). As espécies vegetais e variáveis ââambientais foram investigadas em 38 locais localizados em três regiões. Um total de 15 variáveis ââambientais foi medido em cada local, e as coordenadas geográficas foram usadas para extrair as variáveis ââespaciais (usando PCNM). Um total de 81 espécies de plantas foi relatado em 38 locais. As três regiões mostraram padrões de homogeneidade de dispersões multivariadas (ou seja, diversidade beta). A análise PCNM extraiu 18 vetores PCNM e apenas 3 vetores foram retidos após a seleção direta. As variáveis ââespaciais (vetores PCNM selecionados) explicaram apenas 3,21% da variação na composição de espécies das plantas (utilizando a técnica de partição de variação). No entanto, 8 variáveis ââambientais foram selecionadas após seleção direta (chumbo, cobre, matéria orgânica total, potássio, magnésio, pH, zinco e ferro, F = 4,72, P < 0,05) e explicaram 19,61% da variação total na composição de espécies. Em conclusão, as comunidades vegetais em Sabkhas não foram espacialmente estruturadas devido à baixa porcentagem de variação explicada pelas variáveis ââespaciais (vetores PCNM). As variáveis ââambientais corresponderam à alta fração de variação explicada. Por outro lado, os Sabkhas na Arábia Saudita são considerados um hot spot de diversidade não apenas para plantas, mas para outros animais (aves, vertebrados e invertebrados). Portanto, planos de conservação imediatos devem ser implementados para reduzir os efeitos adversos da urbanização, industrialização e outras atividades antrópicas.
Assuntos
Plantas , Arábia Saudita , Ecossistema , Biodiversidade , Meio AmbienteRESUMO
Lactation curves are a valuable tool for improving flock production efficiency, adjusting flock sizes, and improving farmers' income in grazing-based livestock production. Therefore, we used natural cubic splines to estimate (a) a general flock production pattern throughout a year, (b) an average lactation curve, and (c) patterns of milk chemical components in dual-purpose goats grazing in arid plant communities in the Sierra de San Francisco, Baja California Peninsula, during years of abundant precipitation. Also, milk chemical composition was compared between flocks. Annual flock milk production showed a wiggly pattern with two greater waves in summer and spring. The average individual lactation curve (kg/doe/day) and production curves of fat, protein, lactose, and ashes (g/doe/day) showed a decreasing and wiggly pattern across 35-week lactation; the greatest average daily production was in week 2. Milk, protein, lactose, and ash production curves had similar persistency values that were greater than those of the fat production curve. Milk production had a high-positive correlation with fat production and very high-positive correlations with protein, lactose, and ash production. Density (g/ml) and fat, protein, lactose, and ash contents (%) showed a ditch-shaped pattern across lactation, with greater values at the end. Goat flocks grazing across plant communities produced different quality milk. Thus, native plant communities are a valuable resource that favors a great fat content and moderate protein content in local goat milk. Also, breeding programs must pay attention that an increment in individual milk production could decrease fat and protein production, which are valuable for cheesemaking.
Assuntos
Cabras , Leite , Animais , Feminino , Lactação , Lactose , México , Proteínas do LeiteRESUMO
Recent decades have seen increased research interest in the processes and mechanisms related to insect gall richness and host plants. The data set provided here includes 968 records of interactions between galling insects and host plants for the Cerrado biome. The data set comprises 505 species of 222 genera and 67 families of host plants. The botanical families most represented in the data set are Asteraceae, Fabaceae, Myrtaceae, Malpighiaceae, and Melastomataceae, which account for ~48.5% of all records and 52% of the total number of species. The gall-inducing insects listed in the data set include 48 species of Cecidomyiidae and one species of Tephritidae. This data set is the first to compile inventories of plant-galling insect communities and information about the diversity and distribution of insect galls and their host plants in the Cerrado. The data set reveals knowledge gaps and opportunities for future research on patterns of diversity and distribution, and provides a basis for generating and testing new ecological hypotheses. Please cite this data paper when using the current data in publications and let us know how the data are used in the publications. There are no copyright restrictions.
Assuntos
Fabaceae , Interações Hospedeiro-Parasita , Animais , Ecossistema , Humanos , Insetos , Tumores de PlantaRESUMO
Playa La Vaca está ubicada al noroeste de la ciudad de Moa y desde principios del siglo XX ha sido objeto de interés para los botánicos. Aunque no se ha constatado la existencia de obras publicadas que caractericen la vegetación de esta área clásica de colecta existen muestras de materiales depositados en los herbarios cubanos y extranjeros. La flora y vegetación de esta localiad se desarrolló en suelos derivados de serpentinitas, de las cuales varios autores expresan que son áreas de gran endemismo; esto fundamenta la necesidad de conocer y registrar los valores de diversidad vegetal de esta localidad. Este trabajo abarca una primera parte de la investigación realizada en esta localidad y tiene como objetivo la delimitación y caracterización de las formaciones vegetales presentes en Playa La Vaca. Para esto se recopiló información de la bibliografía y las colectas de plantas realizadas en Playa La Vaca depositadas en el herbario HAC provenientes de las expediciones botánicas y se efectuaron anotaciones en recorridos del trabajo de campo, identificándose 10 formaciones vegetales. Se obtuvo el mapa de vegetación a través del uso de un Sistema de Información Geográfica.
Playa La Vaca is located northwest of Moa city. Since the early twentieth century it has been an interestin site for botanists. There aren't any publication characterizing the vegetation of this classic collection area but it is possible to find a lot of sample materials from this site in Cuban and foreign herbals instead. The flora and vegetation of Playa La Vaca was developed on soils wich are derived from serpentinite rock, because of this, several authors states that this area is of high endemism. This fact, substantiates the need to study and record the diversity value of Playa La Vaca, thus contributing with the sustainable management of the area. This paper covers the first part of the research work conducted in Playa La Vaca locality and it aims to the characterization of plant communities of this site. For this work, it was used information obtained from fieldwork. Information from bibliography and plants collections from Playa La Vaca, deposited in the HAC herbarium were consulted too. Ten plants communities were identified in the locality. The vegetation map was obtained through the use of a Geographic Information System.
Assuntos
Humanos , Plantas , Flora , Herbário , Setaria (Planta)RESUMO
Soils influence tropical forest composition at regional scales. In Panama, data on tree communities and underlying soils indicate that species frequently show distributional associations to soil phosphorus. To understand how these associations arise, we combined a pot experiment to measure seedling responses of 15 pioneer species to phosphorus addition with an analysis of the phylogenetic structure of phosphorus associations of the entire tree community. Growth responses of pioneers to phosphorus addition revealed a clear tradeoff: species from high-phosphorus sites grew fastest in the phosphorus-addition treatment, while species from low-phosphorus sites grew fastest in the low-phosphorus treatment. Traits associated with growth performance remain unclear: biomass allocation, phosphatase activity and phosphorus-use efficiency did not correlate with phosphorus associations; however, phosphatase activity was most strongly down-regulated in response to phosphorus addition in species from high-phosphorus sites. Phylogenetic analysis indicated that pioneers occur more frequently in clades where phosphorus associations are overdispersed as compared with the overall tree community, suggesting that selection on phosphorus acquisition and use may be strongest for pioneer species with high phosphorus demand. Our results show that phosphorus-dependent growth rates provide an additional explanation for the regional distribution of tree species in Panama, and possibly elsewhere.
Assuntos
Fósforo/farmacologia , Plântula/crescimento & desenvolvimento , Plântula/metabolismo , Árvores/crescimento & desenvolvimento , Árvores/metabolismo , Clima Tropical , Biomassa , Fosfoproteínas Fosfatases/metabolismo , Filogenia , Raízes de Plantas/efeitos dos fármacos , Raízes de Plantas/crescimento & desenvolvimento , Plântula/efeitos dos fármacos , Especificidade da Espécie , Árvores/efeitos dos fármacosRESUMO
Quantitative data on the ecology of the main plant communities along an altitudinal gradient in northeastern Mexico were obtained with the aim of identifying the most important environmental variables that affect plant distribution and composition. The main threats to these communities were also investigated. Importance value index (IVi) of the 39 most important species and 16 environmental variables were recorded at 35 altitudinal gradients each spaced at intervals of at least 100-m altitude. Classification and ordination of vegetation showed six well-differentiated but overlapping plant communities: alpine meadow, cold conifer forest, mesic mixed forest, xeric scrub, Tamaulipan piedmont scrub, and halophytic grassland. Altitude, minimum and average temperatures, and organic matter content are the main variables affecting the plant distribution in northeastern Mexico. Urban growth, mechanized agriculture, and changes in land use are the main threats in the short and medium term to plant communities in this area. Climate change also seems to be having an impact at present or in the near future as shown by the presence of exotic shrubs from warmer areas in mesic and temperate areas inhabited by oak and oak-pine forest.
Assuntos
Altitude , Clima , Fenômenos Fisiológicos Vegetais , Plantas/classificação , Mudança Climática , Ecossistema , MéxicoRESUMO
Forest fragmentation affects the structure and dynamics of plant communities, leading to biodiversity loss in forest remnants. In this paper we show that in a bamboo (Guadua weberbaueri Pilger) dominated forest fragment in southwestern Amazonia edge effect may be confounded by bamboo effect, which also occur inside the forest. We measured growth, mortality and, recruitment rate of trees with DBH ≥ 10 cm, in a fragment of bamboo dominated open forest in southwestern Amazonia, state of Acre, Brazil, in 15 plots at the forest edge and 15 plots inside the forest fragment, 500 m away from the border. Time interval between censuses was 1.8 years. The average diameter growth rate differed significantly between edge (3.82 ± 0.10 mm a-1) and interior (2.39 ± 0.18 mm a-1); but there were no differences in annual mortality rate (edge = 3.8 ± 2.5 % a-1 CV = 65.7%; interior = 3.6 ± 2.6% a-1 CV = 72.2%) or in annual recruitment rate (edge = 7.1 ± 3.2% a-1 CV = 45%; interior = 8.9 ± 7.9% a-1 CV = 88.7%). Diameter growth rate, particularly of pioneer and fast-growing trees, is favored by the environmental conditions of the edge, where bamboo abundance is higher. However, the absence of an edge effect on mortality and recruitment could be due to the particular dynamics of bamboo patches, which could be mimicking forest edges and therefore masking possible edge effect in this fragment. We speculate that the mortality and recruitment patterns in fragmented forests of southwestern Amazonia is different from other areas in Amazonia and that bamboo is one of the key controllers of successional processes in these fragments.
A fragmentação florestal afeta a estrutura e dinâmica das comunidades vegetais, levando a perda da biodiversidade nos remanescentes florestais. Neste trabalho nós mostramos que em um fragmento florestal dominado por bambu (Guadua weberbaueri Pilger) no sudoeste da Amazônia, o efeito de borda deve ser confundido pelo efeito efeito do bambu, que também ocorre no interior da floresta. Nós medimos as taxas de incremento diamétrico, mortalidade e recrutamento de árvores com DAP (diâmetro a altura do peito) ≥ 10 cm, em um fragmento dominado por floresta aberta com bambu no sudoeste da Amazônia, estado do Acre, Brasil, em 15 parcelas na borda da floresta e 15 a 500 m da borda no interior do fragmento florestal. O intervalo de tempo entre os censos foi de 1,8 anos. A taxa anual de incremento diamétrico médio diferiu significativamente entre borda (3,82 ± 0,10 mm a-1) e interior (2,39 ± 0,18 mm a-1); mas não houve diferenças na taxa anual de mortalidade (borda = 3.8 ± 2.5% a-1 CV = 65.7%; interior = 3.6 ± 2.6% a-1 CV = 72.2%) e na taxa anual de recrutamento (borda = 7.1 ± 3.2% a-1 CV = 45%; interior = 8.9 ± 7.9% a-1 CV = 88.7%). A taxa de incremento diamétrico, especialmente de espécies arbóreas de estágios iniciais de sucessão ecológica e crescimento rápido, é favorecida pelas condições ambientais da borda, onde a abundância de bambu é maior. Porém, a ausência de efeito de borda sobre a mortalidade e recrutamento, pode ser devido a própria dinâmica das manchas de bambu, que podem estar imitando as bordas das florestas, e portanto, mascarando o efeito de borda neste fragmento. Nós especulamos que os padrões de mortalidade e recrutamento em florestas fragmentadas no Sudoeste da Amazônia são diferentes de outras partes da bacia Amazônica e que o bambu nessas florestas é um dos principais atores controlando a sucessão florestal nesses fragmentos.
RESUMO
A restinga de Praia das Neves ocupa uma extensa área (ca. 67 km2) no extremo sul do Estado do Espírito Santo (21°14′35.35″S e 40°56′48.68″W), limitada pelo Rio Itabapoana, na divisa com o Estado do Rio de Janeiro. O objetivo desse estudo foi identificar e caracterizar as diferentes formações vegetais dessa restinga e sua flora associada, incluindo o reconhecimento dos habitats relacionados ao lagarto ameaçado de extinção Liolaemus lutzae Mertens, 1938. Excursões para caracterização da flora local foram realizadas em campanhas pontuais, entre os anos de 2008 e 2011, e o material botânico foi identificado e posteriormente depositado no Herbário RBR do Departamento de Botânica da Universidade Federal Rural do Rio de Janeiro. A caracterização das diferentes formações encontradas baseou-se em observações locais e na bibliografia especializada, considerando aspectos físicos do ambiente, o hábito e a composição das espécies vegetais. A vegetação da restinga de Praia das Neves reúne sete formações florestais, arbustivas e herbáceas, distribuídas em geral em faixas paralelas a linha da costa. Foram registradas 167 espécies de plantas vasculares, reunidas em 58 famílias, ocorrendo nas diferentes formações. A grande maioria das espécies estudadas é exclusiva de uma única formação, enquanto que Allagoptera arenaria (guriri-da-praia) se destaca por ocorrer em quase todas as formações locais. A restinga de Praia das Neves mantém extensos trechos em bom estado de conservação, com espécies listadas como ameaçadas para a flora do Estado do Espírito Santo e com importantes remanescentes de formações costeiras no Estado. Embora sua maior extensão esteja contida em área privada, ações futuras devem assegurar a preservação da restinga local, com suas formações vegetais e a biota associada, conforme indica a legislação federal vigente.
The sandy coastal plains (restinga) of Praia das Neves occupies a large area (ca. 67 km2) in the southeastern state of Espírito Santo (21°14′35.35″ S and 40°56′48.68″ W), bordered by Itabapoana River on the boundary with the state of Rio de Janeiro. The aim of this study was to identify and characterize the different types of plant communities and associated flora on that sandy coastal plain, including the recognition of the habitats related to the endangered lizard Liolaemus lutzae Mertens, 1938. Field trips to characterize the local flora were carried out on specific campaigns, between the years 2008 and 2011. The plants were identified and deposited in the RBR Herbarium of the Department of Botany at the Universidade Federal Rural do Rio de Janeiro. The communities' characterization was based on local observations and specialized bibliography, considering physical aspects of the environment, habit and composition of plant species. The sandy coastal plain of Praia das Neves brings together seven forest, shrub and herbaceous communities, usually distributed in ridges parallels to the shoreline. There have been recorded 167 species of vascular plants, grouped into 58 families, occurring in different communities. The majority of species occurs in a single community, while Allagoptera arenaria (guriri-da-praia) stands out for occurring in almost all local communities. The restinga of Praia das Neves maintains extensive areas in good environmental conditions, with some species cited in the red list of endangered species in the state of Espírito Santo, and also with important remnants of coastal communities. Although its greatest extension is within a private area, future actions should ensure the preservation of the local restinga, with its different communities and associated biota, according to the current federal legislation.
RESUMO
The objective of this experiment was to evaluate tiller population density and the dynamics of the tillering process in marandu palisade grass subjected to strategies of rotational stocking management and nitrogen fertilization. Treatments corresponded to combinations between two targets of pre-grazing conditions (sward surface height of 25 and 35 cm) and two rates of nitrogen application (50 and 200 kg ha-1 year-1), and were allocated to experimental units according to a 2 x 2 factorial arrangement in a randomised complete block design, with four replications. The following response variables were studied: initial (TPDi), intermediate (TPDm) and final (TPDf) tiller population density as well as the rates of tiller appearance (TAR) and death (TDR) and the tiller population stability index (SI). TPDi was similar to all treatments, with differences in tiller population density becoming more pronounced as the experiment progressed, resulting in larger TPDf on swards managed at 25 cm pre-grazing height. Tiller death was larger on swards managed at 35 cm, with differences in tiller appearance being recorded only from February 2010 onwards. Stability of tiller population was higher on swards managed at 25 cm pre-grazing height. Overall, there was no effect of nitrogen on the studied variables, and the most adequate grazing strategy corresponded to the pre-grazing height of 25 cm, regardless of the nitrogen application rate used.
O objetivo deste experimento foi avaliar a densidade populacional e a dinâmica do perfilhamento em capim-marandu submetido a estratégias de pastejo rotativo e adubação nitrogenada. Os tratamentos corresponderam à combinação de duas metas de altura pré-pastejo (25 e 35 cm) e duas doses de aplicação de nitrogênio (50 e 200 kg ha-1 ano-1) em arranjo fatorial 2 x 2 alocadas às unidades experimentais segundo delineamento de blocos completos casualizados, com quatro repetições. Foram avaliadas a densidade populacional de perfilhos inicial (DPPi), intermediária (DPPm) e final (DPPf), as taxas de aparecimento (TAP), morte (TMP) e o índice de estabilidade (IE) da população de perfilhos. A DPPi foi semelhante para todos os tratamentos, com diferenças se acentuando ao longo da estação de crescimento, resultando em maior DPPf nos pastos manejados a 25 cm de altura pré-pastejo. A mortalidade de perfilhos foi maior nos pastos manejados a 35 cm, com diferenças em aparecimento sendo registradas somente a partir de fevereiro de 2010. Pastos manejados a 25 cm apresentaram maior estabilidade da população de perfilhos. Não houve efeito do nitrogênio nas variáveis analisadas, sendo que a melhor estratégia de manejo correspondeu à altura pré-pastejo de 25 cm, independente da dose de nitrogênio utilizada.
Assuntos
Fertilização , Poaceae , Nitrogênio , PastagensRESUMO
The objective of this experiment was to evaluate tiller population density and the dynamics of the tillering process in marandu palisade grass subjected to strategies of rotational stocking management and nitrogen fertilization. Treatments corresponded to combinations between two targets of pre-grazing conditions (sward surface height of 25 and 35 cm) and two rates of nitrogen application (50 and 200 kg ha-1 year-1), and were allocated to experimental units according to a 2 x 2 factorial arrangement in a randomised complete block design, with four replications. The following response variables were studied: initial (TPDi), intermediate (TPDm) and final (TPDf) tiller population density as well as the rates of tiller appearance (TAR) and death (TDR) and the tiller population stability index (SI). TPDi was similar to all treatments, with differences in tiller population density becoming more pronounced as the experiment progressed, resulting in larger TPDf on swards managed at 25 cm pre-grazing height. Tiller death was larger on swards managed at 35 cm, with differences in tiller appearance being recorded only from February 2010 onwards. Stability of tiller population was higher on swards managed at 25 cm pre-grazing height. Overall, there was no effect of nitrogen on the studied variables, and the most adequate grazing strategy corresponded to the pre-grazing height of 25 cm, reg
RESUMO
The objective of this experiment was to evaluate tiller population density and the dynamics of the tillering process in marandu palisade grass subjected to strategies of rotational stocking management and nitrogen fertilization. Treatments corresponded to combinations between two targets of pre-grazing conditions (sward surface height of 25 and 35 cm) and two rates of nitrogen application (50 and 200 kg ha-1 year-1), and were allocated to experimental units according to a 2 x 2 factorial arrangement in a randomised complete block design, with four replications. The following response variables were studied: initial (TPDi), intermediate (TPDm) and final (TPDf) tiller population density as well as the rates of tiller appearance (TAR) and death (TDR) and the tiller population stability index (SI). TPDi was similar to all treatments, with differences in tiller population density becoming more pronounced as the experiment progressed, resulting in larger TPDf on swards managed at 25 cm pre-grazing height. Tiller death was larger on swards managed at 35 cm, with differences in tiller appearance being recorded only from February 2010 onwards. Stability of tiller population was higher on swards managed at 25 cm pre-grazing height. Overall, there was no effect of nitrogen on the studied variables, and the most adequate grazing strategy corresponded to the pre-grazing height of 25 cm, reg