Behaviour of dispersion indices in pattern detection of a population of angico, Anadenanthera peregrina (Leguminosae)

Malhado, Ana C. M.; Petrere, Miguel

doi:10.1590/s1519-69842004000200009

Cited by 11 publications

(6 citation statements)

References 8 publications

(13 reference statements)

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“…The aggregated distribution patterns frequently encountered in the present study are usually strongly associated with species dispersed by animals or by autochory (barochory) (Antonini and Nunes Freitas 2004;Malhado and Petrere Jr. 2004;Marques and Joly 2000;Vicente et al 2003). Barbosa et al (2003) examined 28 woody species in the caatinga and determined that 47% were autochorous, 32% were zoochorous, and 21% exhibited anemochory.…”

Section: Conservation Prioritiesmentioning

confidence: 49%

Conservation Priorities and Population Structure of Woody Medicinal Plants in an Area of Caatinga Vegetation (Pernambuco State, NE Brazil)

Oliveira

Neto

Araújo

et al. 2007

Environ Monit Assess

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In spite of heavy harvesting pressure on some of the most popular medicinal plant species, there are very few published studies concerning their conservation the semi-arid region of northeastern Brazil. In light of this fact, the present work sought to evaluate the local conservation and the harvesting sustainability of medicinal plants in an region of caatinga vegetation employing a fusion of biological and cultural approaches. Ethnobotanical methodologies and techniques were employed in the community of "Riachão de "Malhada de Pedra"" (municipality of Caruaru, state of Pernambuco, Brazil) in order to document local knowledge concerning medicinal plants and to examine the availability of those plants in a caatinga vegetation fragment located near that community. A total of 21 medicinal plant species were identified in the area and classified according to ecological factors and local uses. Two plants (Ziziphus joazeiro and Myracrodruon urundeuva) stood out has having high priority for conservation efforts. Sixteen species were identified as having populations adequate for harvesting through a system of pre-determined quotas, while four species were deemed sufficiently abundant to be harvested without risk of causing significant impact on their sustainability.

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Section: Conservation Prioritiesmentioning

confidence: 49%

Conservation Priorities and Population Structure of Woody Medicinal Plants in an Area of Caatinga Vegetation (Pernambuco State, NE Brazil)

Oliveira

Neto

Araújo

et al. 2007

Environ Monit Assess

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“…Several such have been proposed, of which Morisita's (1959) index of dispersion (I d ) and Lloyd's (1967) index of patchiness (I p ) have been most widely adopted (e.g. Malhado & Petrere 2004, Kristensen et al 2006, Møller et al 2010, Rindorf & Lewy 2012. These two, with that of Morisita in Smith-Gill's (1975) standardised format (I m ), were calculated for each assemblage metric at each spatial scale.…”

Section: Discussionmentioning

confidence: 99%

Spatial stability of macrobenthic seagrass biodiversity

Barnes¹

2013

Mar. Ecol. Prog. Ser.

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The magnitude and patchiness of macrobenthic biodiversity were compared across spatial scales spanning 5 orders of areal magnitude (ca. 2 m 2 to ca. 1.5 ha) in an intertidal seagrass bed in the warm-temperate Knysna estuarine bay, South Africa. The 75 component species and their populations were highly variably distributed across the site, abundances of the individual dominant animals being significantly patchy and composition of the macrofaunal assemblage being significantly non-uniform. Nevertheless, emergent assemblage attributes exhibited spatial constancy: values of assemblage metrics (faunal abundance, species richness, species density and species diversity) did not differ across the site or across spatial scales, and neither did the patterns of dispersion of species diversity, species richness or observed species density. Distribution of the 2 latter through space was even significantly uniform. Ecological arguments developed for temporal constancy of biodiversity seem broadly applicable to the spatial dimension at Knysna, suggesting that although apparently paradoxical, it may be the varying assemblage composition that permits this spatial stability. There is no evidence, however, that the Knysna seagrass macrobenthos is a competitively-structured assemblage with rigid niche-partitioning, a condition suggested to be necessary for temporal constancy; rather, it is more likely to be open, non-equilibrium and below carrying capacity.

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“…Seed aggregation patterns for the 24 most abundant species were tested using the Morisita index (Morisita, 1959). We used this index because it is not sensitive to density changes, so our values could be compared directly (Malhado and Petrere, 2004). Species composition and abundance were analysed using ordination techniques.…”

Section: Discussionmentioning

confidence: 99%

Spatial coherence between seasonal seed banks in a semi-arid gypsum community: density changes but structure does not

et al. 2005

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Seed banks play a crucial role in arid plant communities because they confer stability and long-term persistence. However, seed banks have high temporal and spatial variability, with dramatic changes in density and composition. The aim of this study was to test whether seasonal change affected seed bank community structure and spatial pattern. Moreover, we wanted to know if the effect driven by environmental factors on the seed bank was constant year round. We sampled the seed bank at 188 points along seven parallel transects through a gypsum system in central Spain. Soil samples were taken twice (September and April) in contiguous plots. In each plot we measured environmental parameters, including micro- and macroslope, vegetation band, shrub cover, lichen crust cover and landform. A nearly threefold decrease in seed bank density occurred between September (16,230 seeds m–2) and April (5960 seeds m–2). Seasonal changes in density varied widely among species; however, a seed bank was present for most species at both sampling dates. For several well-studied species (Lepidium subulatum and Helianthemum squamatum), seed losses were within the range of losses by emergence reported in the literature. In both seasons, seed bank composition was controlled mainly by community band and microslope. Sampling season had a significant, but minor effect on seed bank composition. Moreover, a high spatial correlation existed in terms of seed density and richness through the two studied seasons. These results show that the seed bank keeps a constant structure even under substantial variation in density.

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Behaviour of dispersion indices in pattern detection of a population of angico, Anadenanthera peregrina (Leguminosae)

Cited by 11 publications

References 8 publications

Conservation Priorities and Population Structure of Woody Medicinal Plants in an Area of Caatinga Vegetation (Pernambuco State, NE Brazil)

Conservation Priorities and Population Structure of Woody Medicinal Plants in an Area of Caatinga Vegetation (Pernambuco State, NE Brazil)

Spatial stability of macrobenthic seagrass biodiversity

Spatial coherence between seasonal seed banks in a semi-arid gypsum community: density changes but structure does not

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