Resources
R codes and data
Alien flora are accumulating steadily in China over the last 80 years (2025, iScience)
Analysis 1: Temporal analysis of alien flora accumulation (based on the minimum residence time (MRT) of the alien plant species)
- Fitting nonlinear functions (fitting, compare, plot)
- Segmented regression (breakpoint estimation, plot, linear regression model to identify temporal trend)
- Bootstrap procedure (prediction of temporal trend in the future)
Analysis 2: Comparative analysis (compare the MRT values across categories of biotic and abiotic variables)
Descriptive statistics
Check for normality (Shapiro-Wilk test) and homogeneity of variance (Levene test)
Compare (Kruskal-Wallis H test, post hoc Dunn test, ART ANOVA: non-parametric alternative of 2-way ANOVA)
Analysis 3: Identify the variables’ influence on MRT
Testing for phylogenetic signals (Blomberg’s K and Pagel’s λ)
Univariate regression: logistic regression for variables having no phylogenetic signals, phylogenetic generalised least squares (PGLS) for variables with phylogenetic signals
Multivariate regression: Phylogenetic path analysis (PPA)
LASSO regression: Identification of variables’ categories that can influence the MRT
Access the script and data from here
Implications for biological invasion of non-native plants for sale in the world's largest online market (2024, Conservation Biology)
Analysis 1: Comparison of variables between categories (between the alien species offered for sale and not offered for sale in Chinese online marketplaces)
Descriptive statistics (summarySE)
Check for normality (Shapiro-Wilk test) and homogeneity of variance (Levene test)
Compare and effect size estimation (Wilcox test and t-test, post hoc Dunn test)
Subset data based on criteria
Analysis 2: Regression analysis (identify variables’ influence on the sale availability of alien plant species of three invasion categories)
Fitting a generalised linear model (glm: binomial logistic regression)
Plot regression results using the sjPlot package
Analysis 3: Structural equation modelling (identify variables’ direct and indirect influence on the sale availability of alien plant species of three invasion categories)
Using the lavaan package
Plot result using the semPlot package
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Spatio-temporal pattern of cross-continental invasion (2022, Ecological Indicators)
Analysis 1: Testing spatial niche conservatism (COUE framework) and the environmental analogy between native and non-native ranges
Using the ecospat package
Calculating niche overlap, niche similarity, and niche equivalency
Quantify niche dynamics and plot centroid shift
MESS analysis
Analysis 2: Estimate and compare the rate of spread between the three regions of the species’ introduced range
Custom script
Fitting the exponential growth model
Estimating slope and confidence intervals
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Different factors influence naturalisation and invasion processes (2021, Journal of Environmental Management)
Analysis 1: Comparison of minimum residence time (MRT) between invasion categories
Descriptive statistics (summarise function)
Check for normality (Shapiro-Wilk test) and homogeneity of variance (Levene test)
Compare (ANOVA, Tukey’s HSD, Shapiro-Wilk test, Dunn test)
Analysis 2: Imputation of missing data
Visualisation of missing data
Imputation using the missForest package
Standardisation of variables
Analysis 3: Logistic regression
Testing the effects of the biotic and abiotic variables on invasion success (invasive aliens-1, casual aliens-0)
Analysis 4: Phylogenetic analysis
Making a phylogenetic tree (V.PHYLOMAKER package), and pruning the tree to genus level
Testing for phylogenetic signals (Blomberg’s K and Pagel’s λ), PHYTOOLS package
Access the script and data from here
Glacial vicariance and oceanic circulation shape population structure of the coastal legume (2022, American Journal of Botany)
Analysis 1: Determine the relationship of genetic differentiation with geographic (IBD), environmental (IBE), and resistance (IBR) distances
Partial Mantel test
Multiple Regression on Distance Matrices (MRM)
VIF analysis using the usdm package
Compute Euclidean distances between points
Access the script and data from here
Deciphering the global phylogeography of a coastal shrub (2021, Journal of Systematics and Evolution)
Analysis 1: Identify genetic clusters and describe the relationships between them
Discriminant analysis of principal components
Access the script and data from here
Contrasting Phylogeographic Patterns in Lumnitzera Mangroves (2021, Frontiers in Plant Science)
Analysis 1: To estimate population differentiation based on cpDNA sequence data
Hedrick’s G/ST estimation
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Prominent genetic structure across native and introduced ranges of Pluchea indica (2020, Journal of Plant Ecology)
Analysis 1: To investigate the genetic structure (by integrating the spatial information in the clustering algorithm)
Assess clustering pattern and plotting (GENELAND package)
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Analysis of population structure: high gene flow shaping invasion pattern and inducing range expansion (2020, Annals of Botany)
Analysis 1: To assess the relationship of genetic differentiation with isolation by distance, environment and resistance surfaces
Generalized Dissimilarity Modeling analysis in R to model how genetic differentiation changes with environmental conditions and geographic distance (GDM package)
Access the script and data from here
Native exotic relationships in plant communities (2017, Ecological Research)
Analysis 1: Likelihood ratio test for equality of Poisson means
To compare native species richness between sites invaded by two invasive species, either alone or in combination. The number of native species in a site was assumed to follow a Poisson distribution with mean depending on the presence or absence of the two focal species and their joint occurrence.
Access the script and data from here
Presentations
2025
A data-driven look at India’s alien flora: Annual Research Conclave, Bhopal
The digital gateway to biological invasions: Annual Research Conclave, Bhopal
Data-driven research in invasion biology: Introduction to Interdisciplinary Research, Goa
Welcome to ILORA: 1st User Interaction Meet, Kolkata
2024
Fundamentals of spatial data: Bridging Nature with Data Science workshop, Bhopal
Data and variables: ARC Workshop, Bhopal
Aliens that live amongst us: Summer school, Bhopal
Hiding behind the mountains, devils are spreading: Mountains of Life event, Bhopal
2022
ILORA (Indian Alien Flora Information) database: Eco Data Series, Mumbai
2018
Species Distribution Modelling: SDM Workshop, Kolkata
Multivariate niche visualization: Invasive species workshop, Kolkata
2016
Preliminary thesis defense: Calcutta University
2015
Final annual evaluation: ISI, Kolkata
Niche modelling: India Biodiversity Meet, Kolkata
2014
Impact assessment of Mikania: Tropical Ecology Congress, Delhi [Poster]
Geoinformatics and invasion: UIM, NRSC (Hyderabad)
2013
Growth and spread of Mikania: ICBI, China
2012
Threats of Mikania: Australasian Weeds Conference, Melbourne [Poster]
2011
Review on Mikania micrantha: ADNAT, CCMB (Hyderabad) [Poster]
