Data Transformations in Ecological Ordination: II. On the Meaning of Data Standardization

Noy‐Meir, Imanuel; Walker, Donald A.; Williams, W. T.

doi:10.2307/2258601

Cited by 138 publications

(87 citation statements)

References 35 publications

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“…The number of ordination axes was determined by examining the relationship between stress and number of axes, and by using randomization tests to confirm that each axis in the final analysis explained significantly more variation than expected by chance. All variables were standardized by the relativization by maximum method (Noy-Meir et al 1975) prior to analysis. Sorensen's distance measure was used (comparable results were obtained with different distance metrics and ordination techniques, indicating that the observed patterns were insensitive to the methods used).…”

Section: Discussionmentioning

confidence: 99%

Biomass Dynamics in Amazonian Forest Fragments

Nascimento

Laurance

2004

Ecological Applications

176

135

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Abstract. Habitat fragmentation affects aboveground biomass in Amazonian forests, with potentially important implications for carbon storage and greenhouse gas emissions. We assessed the dynamics of aboveground-biomass stocks by combining long-term (10-19 yr) data on mortality, damage, growth, and recruitment of large (Ն10 cm diameter at breast height [dbh]) trees with measurements of nearly all other live and dead plant material (seedlings, saplings, small trees, palms, lianas, downed wood debris, snags, litter) in 50 1-ha plots in fragmented and continuous Amazonian forests.The key process altering biomass dynamics in fragmented forests is the chronically elevated mortality of large trees, which apparently results from microclimatic changes and increased wind turbulence near forest edges. This, in turn, accelerates the production of necromass and leads to significantly increased wood debris and litter on the forest floor. Near forest edges, frequent canopy disturbance increases the amount of light in the understory, resulting in accelerated tree recruitment, significantly higher biomass of small (5-10 cm dbh) trees, and higher liana densities. Surprisingly, the estimated annual turnover of wood debris increases significantly near forest edges, suggesting that decomposition is occurring more rapidly in fragmented than continuous forests.These results reveal that habitat fragmentation fundamentally alters the distribution and dynamics of aboveground biomass in Amazonian forests. The rate of carbon cycling probably increases sharply, both because long-lived canopy and emergent trees decline in favor of shorter-lived successional trees and lianas, and because necromass production and turnover both appear to increase. Carbon storage in live vegetation also declines because small successional trees and lianas (which typically have low wood density) store substantially less carbon than do large, old-growth trees. Finally, the decline and rapid decay of live biomass in forest fragments may produce substantial atmospheric carbon emissions, above and beyond that resulting from deforestation per se.

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Section: Discussionmentioning

confidence: 99%

Biomass Dynamics in Amazonian Forest Fragments

Nascimento

Laurance

2004

Ecological Applications

176

135

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“…A matriz de dados "espécies × parcelas" foi estandarizada (Noy-Meir et al 1975) para análise de agrupamento. Evitou-se a centralização da matriz para que possíveis relações entre parcelas que mostram variações graduais não se perdessem (Noy-Meir 1973).…”

Section: Methodsunclassified

Estrutura e composição do componente arbóreo na Reserva Ecológica do Trabiju, Pindamonhangaba, SP, Brasil

2005

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RESUMO -(Estrutura e composição do componente arbóreo na Reserva Ecológica do Trabiju, Pindamonhangaba, SP, Brasil). Este estudo examinou a composição, a estrutura e a distribuição do componente arbóreo de floresta montana em Pindamonhangaba, SP, Brasil. Todas as árvores com diâmetro do caule a 1,30 cm de altura do solo (DAP) ≥ 5 cm foram amostradas em dez parcelas de 10×25 m, entre 680 m e 805 m de altitude. Foram registradas 517 árvores em um total de 75 espécies, de 69 gêneros e 40 famílias de plantas vasculares. A estrutura de comunidade foi caracterizada pelo domínio de Euterpe edulis Mart. (51,26% do total de plantas), o que causou baixo índice de diversidade de Shannon (2.5910 nats). A estrutura da floresta apresentou alta densidade (2068 ind./ha) e área basal (44,36 m 2 /ha). Isto foi atribuído à maturidade da floresta, onde espécies secundárias apresentaram árvores de grande porte e ausência de indivíduos jovens. A composição de espécies variou continuamente ao longo dos 125 m de diferença altitudinal, como mostrado pela análise de agrupamento. A comparação com outros trechos de florestas por dados de presença × ausência mostrou que há maior semelhança com as florestas no Planalto Atlântico do leste e sul do Estado de São Paulo, sob clima mais úmido e temperaturas médias anuais mais baixas.Palavras-chave: Floresta Atlântica Montana, estrutura da vegetação, comunidade arbórea, fragmento florestal, floresta secundária ABSTRACT -(Structure of tree component in Reserva Ecológica do Trabijú, Pindamonhangaba, São Paulo State, Brazil). This study examined composition, structure and distribution of tree component in the montane forest in Pindamonhangaba, São Paulo State, Brazil. All trees with a trunk diameter at breast height (DBH) ≥ 5 cm were sampled in ten 10×25 m plots stablished between 680 m and 805 m a.s.l. were recorded 517 trees. A total of 75 species, 69 genera on 40 families of vascular plants ocurred in the plots. The community structure was characterized by dominance of Euterpe edulis Mart. (51,26% of total plants), which caused a low Shannon diversity index (2,5910 nats). The forest strucutre was characterized by a high density (2,068 ind./ha) and basal area (44,36 m 2 /ha). This was atributed to the forest maturity, where secondary species ocurred with great trees and young individuals were absent. Species compositon varied continuously with altitude over a 125 m range, as shown by a cluster analysis. The comparison with others forest areas by use of presence × abscense data showed a higher similarity with Planalto Atlântico forests under wettest and lower mean anual temperature in the east and south of São Paulo State.

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“…Standardization is necessary if we are analysing variables that are measured in different units, for example quantitative environmental variables such as pH, mass fraction of organic matter or ion concentrations. Noy Meir et al (1975) fully discuss the virtues and vices of various data transformations in PCA.…”

Section: Data Transformationmentioning

confidence: 99%

Data Analysis in Community and Landscape Ecology

1995

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Ecological data has several special properties: the presence or absence of species on a semi-quantitative abundance scale; non-linear relationships between species and environmental factors; and high inter-correlations among species and among environmental variables. The analysis of such data is important to the interpretation of relationships within plant and animal communities and with their environments. In this corrected version of Data Analysis in Community and Landscape Ecology, without using complex mathematics, the contributors demonstrate the methods that have proven most useful, with examples, exercises and case-studies. Chapters explain in an elementary way powerful data analysis techniques such as logic regression, canonical correspondence analysis, and kriging.

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Data Transformations in Ecological Ordination: II. On the Meaning of Data Standardization

Cited by 138 publications

References 35 publications

Biomass Dynamics in Amazonian Forest Fragments

Biomass Dynamics in Amazonian Forest Fragments

Estrutura e composição do componente arbóreo na Reserva Ecológica do Trabiju, Pindamonhangaba, SP, Brasil

Data Analysis in Community and Landscape Ecology

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