###################################
## Q7 — Modo R vs. Modo Q        ##
## Autora: Victória Souza        ##
###################################

Modo R.: Compara variáveis (colunas): opera sobre a matriz amostras×variáveis e investiga a dependência/associação entre descritores via correlação ou variância–covariância (matriz pxp). O objetivo é sintetizar redundâncias dos descritores em poucos eixos ortogonais (autovetores/autovalores), revelando gradientes ambientais e colinearidade. Exemplo: PCA (rda(amb, scale=TRUE)), que decompõe a matriz de correlações e projeta as amostras nos eixos definidos pelas variáveis (biplot).

# Exemplo R-script pca:

#Lendo os dados:
dados<-read.table("insetos.txt", h=T, sep="\t", dec=".")
dados
##    UA        Ambiente     Gado Temperatura Cobertura.vegetal Proporcao.de.luz
## 1   1   Mata Primaria Presente        21.8                73             53.5
## 2   2   Mata Primaria Presente        21.5                59             61.5
## 3   3   Mata Primaria  Ausente        21.7                78             53.0
## 4   4   Mata Primaria  Ausente        19.7                74             56.0
## 5   5   Mata Primaria Presente        24.7                48             71.0
## 6   6   Mata Primaria Presente        20.2                75             60.5
## 7   7   Mata Primaria  Ausente        23.0                78             57.0
## 8   8   Mata Primaria Presente        27.3                52             70.0
## 9   9   Mata Primaria Presente        23.3                40             70.0
## 10 10   Mata Primaria  Ausente        26.7                52             68.0
## 11 11   Mata Primaria  Ausente        21.5                69             61.5
## 12 12 Mata Secundaria Presente        29.5                27             82.5
## 13 13 Mata Secundaria  Ausente        22.7                56             65.0
## 14 14 Mata Secundaria  Ausente        31.2                35             81.5
## 15 15 Mata Secundaria Presente        30.0                36             81.0
## 16 16 Mata Secundaria  Ausente        30.0                30             84.0
## 17 17 Mata Secundaria Presente        26.2                49             69.5
## 18 18 Mata Secundaria  Ausente        26.2                49             75.5
## 19 19 Mata Secundaria  Ausente        25.7                42             77.0
## 20 20 Mata Secundaria Presente        29.7                34             80.0
##    Numero.de.flores sp.1 sp.2 sp.3 sp.4 sp.5 sp.6 sp.7 sp.8 sp.9 sp.10 sp.11
## 1                14    4    0    7    2    0    0    3    2    1     1     0
## 2                15    5    0    7    2    1    4    1    2    0     1     0
## 3                24    1    0    2    4    0    3    4    3    0     1     2
## 4                29    0    1    1    3    4    9    2    0    0     0     2
## 5                20    6    4    8    3    0    8    1    1    1     1     0
## 6                 5    3    0    3    1    0    0    3    0    0     1     0
## 7                28    4    1    5    2    0    7    6    2    3     1     0
## 8                10    4    0    4    0    0    5    2    2    2     6     0
## 9                 8    4    0    7    0    0    1    2    5    2     3     0
## 10               17    4    3    5    0    0    5    0    6    0     3     0
## 11               26    0    3    5    1    2    7    3    4    0     0     0
## 12               25    6    0    9    2    3    4    0    3    3     3     3
## 13               47    5    2    7    8    2   20    4    1    2     2    11
## 14               36    4    5   10    7    5   14    0    7    5     1     3
## 15               27    6    0   10    4    2    8    0    4    5     3     4
## 16               40    4    1    6    5    5   17    0    6    2     0     6
## 17               39    5    0    4    6    1    8    3    3    2     2     5
## 18               43    4    1    4    7    4   14    3    5    2     2     8
## 19               35    6    1    4    8    0   12    0    3    3     0     7
## 20               23    5    1    4    4    1    2    1    5    6     0     5
##    sp.12 sp.13 sp.14 sp.15 sp.16 sp.17 sp.18 sp.19 sp.20 sp.21 sp.22 sp.23
## 1      1     3     3     0     3     0     0     0     0     0     1     1
## 2      0     3     5     1     0     0     1     3     0     2     2     1
## 3      2     2     2     0     0     0     3     0     4     1     2     1
## 4      5     1     5     0     0     0     0     2     2     3     2     1
## 5      0     4     8     1     1     0     2     0     0     3     2     2
## 6      0     2     0     0     0     0     0     1     0     2     2     1
## 7      0     3     6     0     0     0     2     2     4     3     2     1
## 8      2     0     4     0     0     0     1     4     0     1     2     1
## 9      1     0     4     0     3     0     0     3     0     3     1     1
## 10     0     1     5     2     4     0     0     0     0     3     1     1
## 11     3     0     6     0     3     0     2     0     2     3     2     2
## 12     0     4     6     2     0     0     0     0     0     4     2     1
## 13     9     6    13     2     1     1     3     0     0     1     2     0
## 14     2     5    12     5     0     0     0     0     0     2     3     0
## 15     3     5     9     4     0     0     0     0     0     2     3     1
## 16     4     4    11     3     0     4     3     0     0     2     2     0
## 17     1     5     6     0     0     1     0     0     0     4     1     1
## 18     3     5     9     1     0     6     0     0     0     3     2     1
## 19     6     7     8     3     0     0     0     0     0     3     3     1
## 20     0     4     3     4     0     0     0     0     0     2     1     0
##    sp.24 sp.25 sp.26 sp.27 sp.28 sp.29 sp.30 sp.31 sp.32 sp.33 sp.34 sp.35
## 1      1     0     2     0     1     0     0     1     0     0     0     0
## 2      1     0     1     0     0     1     0     1     1     1     0     3
## 3      2     1     1     0     0     0     0     1     0     0     0     0
## 4      1     0     1     0     0     0     0     0     0     0     0     1
## 5      1     0     1     0     0     0     0     1     1     0     1     0
## 6      1     1     1     0     2     0     0     1     0     0     1     0
## 7      1     2     0     0     0     0     0     0     0     0     0     1
## 8      1     0     1     1     0     0     0     0     0     0     0     0
## 9      0     1     1     0     0     0     0     1     0     0     0     0
## 10     2     2     1     1     0     0     0     1     0     0     0     0
## 11     1     1     1     0     0     0     0     1     0     1     0     0
## 12     0     0     0     0     0     0     0     0     0     0     0     0
## 13     0     1     0     0     0     0     0     1     0     1     0     0
## 14     0     1     0     0     0     0     0     1     0     0     0     0
## 15     0     1     0     0     0     0     1     1     0     0     0     0
## 16     0     1     0     0     0     0     0     1     1     0     0     0
## 17     0     2     0     0     0     0     2     0     0     0     0     0
## 18     0     1     0     0     0     0     0     1     1     0     0     0
## 19     0     1     0     0     0     3     0     0     0     0     0     0
## 20     0     1     0     0     1     0     0     0     0     0     0     0
##    sp.36 sp.37 sp.38 sp.39 sp.40 sp.41
## 1      0     0     0     0     0     0
## 2      0     1     0     0     1     0
## 3      0     0     0     3     0     0
## 4      0     0     0     2     0     0
## 5      0     0     0     0     0     0
## 6      0     0     0     1     0     0
## 7      0     0     0     0     1     0
## 8      0     0     0     0     0     0
## 9      0     0     0     0     0     0
## 10     0     0     0     0     0     0
## 11     0     0     0     0     0     0
## 12     0     0     0     0     0     0
## 13     0     0     0     0     0     0
## 14     0     0     7     0     0     2
## 15     0     0     0     0     0     0
## 16     0     0     3     0     0     7
## 17     0     0     0     0     0     0
## 18     1     0     5     0     0     3
## 19     2     0     0     0     0     0
## 20     0     0     1     0     0     1
#Conferindo:
str(dados)
## 'data.frame':    20 obs. of  48 variables:
##  $ UA               : int  1 2 3 4 5 6 7 8 9 10 ...
##  $ Ambiente         : chr  "Mata Primaria" "Mata Primaria" "Mata Primaria" "Mata Primaria" ...
##  $ Gado             : chr  "Presente" "Presente" "Ausente" "Ausente" ...
##  $ Temperatura      : num  21.8 21.5 21.7 19.7 24.7 20.2 23 27.3 23.3 26.7 ...
##  $ Cobertura.vegetal: int  73 59 78 74 48 75 78 52 40 52 ...
##  $ Proporcao.de.luz : num  53.5 61.5 53 56 71 60.5 57 70 70 68 ...
##  $ Numero.de.flores : int  14 15 24 29 20 5 28 10 8 17 ...
##  $ sp.1             : int  4 5 1 0 6 3 4 4 4 4 ...
##  $ sp.2             : int  0 0 0 1 4 0 1 0 0 3 ...
##  $ sp.3             : int  7 7 2 1 8 3 5 4 7 5 ...
##  $ sp.4             : int  2 2 4 3 3 1 2 0 0 0 ...
##  $ sp.5             : int  0 1 0 4 0 0 0 0 0 0 ...
##  $ sp.6             : int  0 4 3 9 8 0 7 5 1 5 ...
##  $ sp.7             : int  3 1 4 2 1 3 6 2 2 0 ...
##  $ sp.8             : int  2 2 3 0 1 0 2 2 5 6 ...
##  $ sp.9             : int  1 0 0 0 1 0 3 2 2 0 ...
##  $ sp.10            : int  1 1 1 0 1 1 1 6 3 3 ...
##  $ sp.11            : int  0 0 2 2 0 0 0 0 0 0 ...
##  $ sp.12            : int  1 0 2 5 0 0 0 2 1 0 ...
##  $ sp.13            : int  3 3 2 1 4 2 3 0 0 1 ...
##  $ sp.14            : int  3 5 2 5 8 0 6 4 4 5 ...
##  $ sp.15            : int  0 1 0 0 1 0 0 0 0 2 ...
##  $ sp.16            : int  3 0 0 0 1 0 0 0 3 4 ...
##  $ sp.17            : int  0 0 0 0 0 0 0 0 0 0 ...
##  $ sp.18            : int  0 1 3 0 2 0 2 1 0 0 ...
##  $ sp.19            : int  0 3 0 2 0 1 2 4 3 0 ...
##  $ sp.20            : int  0 0 4 2 0 0 4 0 0 0 ...
##  $ sp.21            : int  0 2 1 3 3 2 3 1 3 3 ...
##  $ sp.22            : int  1 2 2 2 2 2 2 2 1 1 ...
##  $ sp.23            : int  1 1 1 1 2 1 1 1 1 1 ...
##  $ sp.24            : int  1 1 2 1 1 1 1 1 0 2 ...
##  $ sp.25            : int  0 0 1 0 0 1 2 0 1 2 ...
##  $ sp.26            : int  2 1 1 1 1 1 0 1 1 1 ...
##  $ sp.27            : int  0 0 0 0 0 0 0 1 0 1 ...
##  $ sp.28            : int  1 0 0 0 0 2 0 0 0 0 ...
##  $ sp.29            : int  0 1 0 0 0 0 0 0 0 0 ...
##  $ sp.30            : int  0 0 0 0 0 0 0 0 0 0 ...
##  $ sp.31            : int  1 1 1 0 1 1 0 0 1 1 ...
##  $ sp.32            : int  0 1 0 0 1 0 0 0 0 0 ...
##  $ sp.33            : int  0 1 0 0 0 0 0 0 0 0 ...
##  $ sp.34            : int  0 0 0 0 1 1 0 0 0 0 ...
##  $ sp.35            : int  0 3 0 1 0 0 1 0 0 0 ...
##  $ sp.36            : int  0 0 0 0 0 0 0 0 0 0 ...
##  $ sp.37            : int  0 1 0 0 0 0 0 0 0 0 ...
##  $ sp.38            : int  0 0 0 0 0 0 0 0 0 0 ...
##  $ sp.39            : int  0 0 3 2 0 1 0 0 0 0 ...
##  $ sp.40            : int  0 1 0 0 0 0 1 0 0 0 ...
##  $ sp.41            : int  0 0 0 0 0 0 0 0 0 0 ...
#Separando em partes:
amb<-dados[ , 4:7] #Constrói a matriz amostras × variáveis, selecionando 4 variáveis ambientais (colunas)
bio<-dados[ , 8:48]

#Pacotes:
library(vegan)
## Carregando pacotes exigidos: permute
#PCA, na qual o argumento scale=T automaticamente irá padronizar os dados (matriz de correlações pxp): foco na associação entre descritores.
resultado.pca<-rda(amb, scale=T)

#Avaliando os resultados: Partitioning of correlations e autovalores (PC1, PC2, PC3, PC4)
summary(resultado.pca)
## 
## Call:
## rda(X = amb, scale = T) 
## 
## Partitioning of correlations:
##               Inertia Proportion
## Total               4          1
## Unconstrained       4          1
## 
## Eigenvalues, and their contribution to the correlations 
## 
## Importance of components:
##                          PC1    PC2     PC3      PC4
## Eigenvalue            2.9688 0.8603 0.13929 0.031552
## Proportion Explained  0.7422 0.2151 0.03482 0.007888
## Cumulative Proportion 0.7422 0.9573 0.99211 1.000000
#Gráfico
biplot(resultado.pca)

Modo Q.: Compara amostras (linhas): transforma a matriz amostras×variáveis em uma matriz triangular de (dis)similaridade nxn entre linhas e ordena/agrupa as amostras segundo uma métrica ecológica. Base para explorar beta-diversidade e padrões de comunidade. Exemplo: nMDS (non-metric Multidimensional Scaling), que representa as amostras em baixa dimensão preservando a ordem das dissimilaridades (stress como medida de ajuste). Métricas usuais: Bray–Curtis para abundância (ignora duplos zeros e capta diferenças relativas); Jaccard/Sorensen para presença/ausência (não contam dupla ausência).

# Exemplo R-script nmds:

#Lendo od dados:
dados<-read.table("insetos.txt", h=T, sep="\t", dec=".")

#Conferindo:
str(dados)
## 'data.frame':    20 obs. of  48 variables:
##  $ UA               : int  1 2 3 4 5 6 7 8 9 10 ...
##  $ Ambiente         : chr  "Mata Primaria" "Mata Primaria" "Mata Primaria" "Mata Primaria" ...
##  $ Gado             : chr  "Presente" "Presente" "Ausente" "Ausente" ...
##  $ Temperatura      : num  21.8 21.5 21.7 19.7 24.7 20.2 23 27.3 23.3 26.7 ...
##  $ Cobertura.vegetal: int  73 59 78 74 48 75 78 52 40 52 ...
##  $ Proporcao.de.luz : num  53.5 61.5 53 56 71 60.5 57 70 70 68 ...
##  $ Numero.de.flores : int  14 15 24 29 20 5 28 10 8 17 ...
##  $ sp.1             : int  4 5 1 0 6 3 4 4 4 4 ...
##  $ sp.2             : int  0 0 0 1 4 0 1 0 0 3 ...
##  $ sp.3             : int  7 7 2 1 8 3 5 4 7 5 ...
##  $ sp.4             : int  2 2 4 3 3 1 2 0 0 0 ...
##  $ sp.5             : int  0 1 0 4 0 0 0 0 0 0 ...
##  $ sp.6             : int  0 4 3 9 8 0 7 5 1 5 ...
##  $ sp.7             : int  3 1 4 2 1 3 6 2 2 0 ...
##  $ sp.8             : int  2 2 3 0 1 0 2 2 5 6 ...
##  $ sp.9             : int  1 0 0 0 1 0 3 2 2 0 ...
##  $ sp.10            : int  1 1 1 0 1 1 1 6 3 3 ...
##  $ sp.11            : int  0 0 2 2 0 0 0 0 0 0 ...
##  $ sp.12            : int  1 0 2 5 0 0 0 2 1 0 ...
##  $ sp.13            : int  3 3 2 1 4 2 3 0 0 1 ...
##  $ sp.14            : int  3 5 2 5 8 0 6 4 4 5 ...
##  $ sp.15            : int  0 1 0 0 1 0 0 0 0 2 ...
##  $ sp.16            : int  3 0 0 0 1 0 0 0 3 4 ...
##  $ sp.17            : int  0 0 0 0 0 0 0 0 0 0 ...
##  $ sp.18            : int  0 1 3 0 2 0 2 1 0 0 ...
##  $ sp.19            : int  0 3 0 2 0 1 2 4 3 0 ...
##  $ sp.20            : int  0 0 4 2 0 0 4 0 0 0 ...
##  $ sp.21            : int  0 2 1 3 3 2 3 1 3 3 ...
##  $ sp.22            : int  1 2 2 2 2 2 2 2 1 1 ...
##  $ sp.23            : int  1 1 1 1 2 1 1 1 1 1 ...
##  $ sp.24            : int  1 1 2 1 1 1 1 1 0 2 ...
##  $ sp.25            : int  0 0 1 0 0 1 2 0 1 2 ...
##  $ sp.26            : int  2 1 1 1 1 1 0 1 1 1 ...
##  $ sp.27            : int  0 0 0 0 0 0 0 1 0 1 ...
##  $ sp.28            : int  1 0 0 0 0 2 0 0 0 0 ...
##  $ sp.29            : int  0 1 0 0 0 0 0 0 0 0 ...
##  $ sp.30            : int  0 0 0 0 0 0 0 0 0 0 ...
##  $ sp.31            : int  1 1 1 0 1 1 0 0 1 1 ...
##  $ sp.32            : int  0 1 0 0 1 0 0 0 0 0 ...
##  $ sp.33            : int  0 1 0 0 0 0 0 0 0 0 ...
##  $ sp.34            : int  0 0 0 0 1 1 0 0 0 0 ...
##  $ sp.35            : int  0 3 0 1 0 0 1 0 0 0 ...
##  $ sp.36            : int  0 0 0 0 0 0 0 0 0 0 ...
##  $ sp.37            : int  0 1 0 0 0 0 0 0 0 0 ...
##  $ sp.38            : int  0 0 0 0 0 0 0 0 0 0 ...
##  $ sp.39            : int  0 0 3 2 0 1 0 0 0 0 ...
##  $ sp.40            : int  0 1 0 0 0 0 1 0 0 0 ...
##  $ sp.41            : int  0 0 0 0 0 0 0 0 0 0 ...
#Separando em partes:
amb<-dados[ , 4:7]
bio<-dados[ , 8:48] #Matriz amostras × espécies (linhas = sites; colunas = espécies)
bio
##    sp.1 sp.2 sp.3 sp.4 sp.5 sp.6 sp.7 sp.8 sp.9 sp.10 sp.11 sp.12 sp.13 sp.14
## 1     4    0    7    2    0    0    3    2    1     1     0     1     3     3
## 2     5    0    7    2    1    4    1    2    0     1     0     0     3     5
## 3     1    0    2    4    0    3    4    3    0     1     2     2     2     2
## 4     0    1    1    3    4    9    2    0    0     0     2     5     1     5
## 5     6    4    8    3    0    8    1    1    1     1     0     0     4     8
## 6     3    0    3    1    0    0    3    0    0     1     0     0     2     0
## 7     4    1    5    2    0    7    6    2    3     1     0     0     3     6
## 8     4    0    4    0    0    5    2    2    2     6     0     2     0     4
## 9     4    0    7    0    0    1    2    5    2     3     0     1     0     4
## 10    4    3    5    0    0    5    0    6    0     3     0     0     1     5
## 11    0    3    5    1    2    7    3    4    0     0     0     3     0     6
## 12    6    0    9    2    3    4    0    3    3     3     3     0     4     6
## 13    5    2    7    8    2   20    4    1    2     2    11     9     6    13
## 14    4    5   10    7    5   14    0    7    5     1     3     2     5    12
## 15    6    0   10    4    2    8    0    4    5     3     4     3     5     9
## 16    4    1    6    5    5   17    0    6    2     0     6     4     4    11
## 17    5    0    4    6    1    8    3    3    2     2     5     1     5     6
## 18    4    1    4    7    4   14    3    5    2     2     8     3     5     9
## 19    6    1    4    8    0   12    0    3    3     0     7     6     7     8
## 20    5    1    4    4    1    2    1    5    6     0     5     0     4     3
##    sp.15 sp.16 sp.17 sp.18 sp.19 sp.20 sp.21 sp.22 sp.23 sp.24 sp.25 sp.26
## 1      0     3     0     0     0     0     0     1     1     1     0     2
## 2      1     0     0     1     3     0     2     2     1     1     0     1
## 3      0     0     0     3     0     4     1     2     1     2     1     1
## 4      0     0     0     0     2     2     3     2     1     1     0     1
## 5      1     1     0     2     0     0     3     2     2     1     0     1
## 6      0     0     0     0     1     0     2     2     1     1     1     1
## 7      0     0     0     2     2     4     3     2     1     1     2     0
## 8      0     0     0     1     4     0     1     2     1     1     0     1
## 9      0     3     0     0     3     0     3     1     1     0     1     1
## 10     2     4     0     0     0     0     3     1     1     2     2     1
## 11     0     3     0     2     0     2     3     2     2     1     1     1
## 12     2     0     0     0     0     0     4     2     1     0     0     0
## 13     2     1     1     3     0     0     1     2     0     0     1     0
## 14     5     0     0     0     0     0     2     3     0     0     1     0
## 15     4     0     0     0     0     0     2     3     1     0     1     0
## 16     3     0     4     3     0     0     2     2     0     0     1     0
## 17     0     0     1     0     0     0     4     1     1     0     2     0
## 18     1     0     6     0     0     0     3     2     1     0     1     0
## 19     3     0     0     0     0     0     3     3     1     0     1     0
## 20     4     0     0     0     0     0     2     1     0     0     1     0
##    sp.27 sp.28 sp.29 sp.30 sp.31 sp.32 sp.33 sp.34 sp.35 sp.36 sp.37 sp.38
## 1      0     1     0     0     1     0     0     0     0     0     0     0
## 2      0     0     1     0     1     1     1     0     3     0     1     0
## 3      0     0     0     0     1     0     0     0     0     0     0     0
## 4      0     0     0     0     0     0     0     0     1     0     0     0
## 5      0     0     0     0     1     1     0     1     0     0     0     0
## 6      0     2     0     0     1     0     0     1     0     0     0     0
## 7      0     0     0     0     0     0     0     0     1     0     0     0
## 8      1     0     0     0     0     0     0     0     0     0     0     0
## 9      0     0     0     0     1     0     0     0     0     0     0     0
## 10     1     0     0     0     1     0     0     0     0     0     0     0
## 11     0     0     0     0     1     0     1     0     0     0     0     0
## 12     0     0     0     0     0     0     0     0     0     0     0     0
## 13     0     0     0     0     1     0     1     0     0     0     0     0
## 14     0     0     0     0     1     0     0     0     0     0     0     7
## 15     0     0     0     1     1     0     0     0     0     0     0     0
## 16     0     0     0     0     1     1     0     0     0     0     0     3
## 17     0     0     0     2     0     0     0     0     0     0     0     0
## 18     0     0     0     0     1     1     0     0     0     1     0     5
## 19     0     0     3     0     0     0     0     0     0     2     0     0
## 20     0     1     0     0     0     0     0     0     0     0     0     1
##    sp.39 sp.40 sp.41
## 1      0     0     0
## 2      0     1     0
## 3      3     0     0
## 4      2     0     0
## 5      0     0     0
## 6      1     0     0
## 7      0     1     0
## 8      0     0     0
## 9      0     0     0
## 10     0     0     0
## 11     0     0     0
## 12     0     0     0
## 13     0     0     0
## 14     0     0     2
## 15     0     0     0
## 16     0     0     7
## 17     0     0     0
## 18     0     0     3
## 19     0     0     0
## 20     0     0     1
#Pacotes:
library(vegan)

#NMDS

#Criando a matriz de distância:
bio.bray<-vegdist(bio, method="bray")  #Construção da matriz de (dis)similaridade n×n, a partir da distância entre amostras (Bray-Curtis, abundância)

#Executando a análise
resultado.nmds<-metaMDS(bio.bray)
## Run 0 stress 0.1174905 
## Run 1 stress 0.1468697 
## Run 2 stress 0.1174905 
## ... New best solution
## ... Procrustes: rmse 5.994328e-06  max resid 1.924531e-05 
## ... Similar to previous best
## Run 3 stress 0.1173347 
## ... New best solution
## ... Procrustes: rmse 0.01085136  max resid 0.03827696 
## Run 4 stress 0.1174905 
## ... Procrustes: rmse 0.01085182  max resid 0.03825455 
## Run 5 stress 0.1474343 
## Run 6 stress 0.1174905 
## ... Procrustes: rmse 0.01085057  max resid 0.03825196 
## Run 7 stress 0.1575512 
## Run 8 stress 0.1625869 
## Run 9 stress 0.1468697 
## Run 10 stress 0.1626549 
## Run 11 stress 0.1174905 
## ... Procrustes: rmse 0.01085041  max resid 0.03824881 
## Run 12 stress 0.1173347 
## ... Procrustes: rmse 5.103745e-05  max resid 0.0001633449 
## ... Similar to previous best
## Run 13 stress 0.1800777 
## Run 14 stress 0.1174905 
## ... Procrustes: rmse 0.01085147  max resid 0.03825334 
## Run 15 stress 0.1799474 
## Run 16 stress 0.1468697 
## Run 17 stress 0.1575511 
## Run 18 stress 0.1468697 
## Run 19 stress 0.1173347 
## ... New best solution
## ... Procrustes: rmse 2.985499e-06  max resid 9.699731e-06 
## ... Similar to previous best
## Run 20 stress 0.1174905 
## ... Procrustes: rmse 0.01085156  max resid 0.03825323 
## *** Best solution repeated 1 times
#Visualizando o resultado, gráfico:
plot(resultado.nmds)
## species scores not available

#Melhorando o gráfico, de acordo com contexto:
cores<-c("green4", "red4")

plot(resultado.nmds, type="n")
## species scores not available
points(resultado.nmds, col=cores[dados$Ambiente], pch=16)
ordihull(resultado.nmds, groups=dados$Ambiente, col=cores, lty=2)
text(resultado.nmds, labels = row.names(bio), pos=4)

resultado.envfit<-envfit(resultado.nmds, amb) #envfit projeta gradientes ambientais sobre o modo Q
resultado.envfit
## 
## ***VECTORS
## 
##                      NMDS1    NMDS2     r2 Pr(>r)    
## Temperatura        0.60649 -0.79509 0.6568  0.001 ***
## Cobertura.vegetal -0.59103  0.80665 0.7202  0.001 ***
## Proporcao.de.luz   0.67408 -0.73866 0.6789  0.001 ***
## Numero.de.flores   0.86447  0.50268 0.8671  0.001 ***
## ---
## Signif. codes:  0 '***' 0.001 '**' 0.01 '*' 0.05 '.' 0.1 ' ' 1
## Permutation: free
## Number of permutations: 999
plot(resultado.envfit) #o gráfico mostra sites (e envoltórios por grupo); as variáveis entram apenas como vetores de interpretação (envfit).