Original Research
12 January 2023
10.3389/fenvs.2022.1037319
TYPE
PUBLISHED
DOI
OPEN ACCESS
EDITED BY
Adriano Sfriso,
Ca’ Foscari University of Venice, Italy
REVIEWED BY
Marion Adelheid Wolf,
University of Ferrara, Italy
Fredrick Ojija,
Mbeya University of Science and
Technology, Tanzania
Paired plot experiments to assess
impact of invasive species on
native floral diversity in Pakistan
Huma Qureshi 1*, Tauseef Anwar 2, Muhammad Mohibullah 3,
Sammer Fatima 4, Rafia Younas 5, Ume Habiba 5, Laraib Malik 6,
Asma Hanif 7 and Muhammad Iqbal 1
1
*CORRESPONDENCE
Huma Qureshi,
huma.qureshi@uoc.edu.pk
SPECIALTY SECTION
This article was submitted to
Conservation and Restoration Ecology,
a section of the journal
Frontiers in Environmental Science
05 September 2022
02 December 2022
PUBLISHED 12 January 2023
Department of Botany, University of Chakwal, Chakwal, Pakistan, 2Department of Botany, The Islamia
University of Bahawalpur (Baghdad-ul-Jadeed Campus), Bahawalpur, Pakistan, 3Department of Plant
Breeding & Genetics, Faculty of Agriculture, Gomal University, Dera Ismail Khan, Pakistan, 4Department
of Botany, University of Gujrat, Gujrat, Pakistan, 5Department of Environmental Science, Gomal
University, Dera Ismail Khan, Pakistan, 6Department of Environmental Science, Government College
University, Faisalabad, Pakistan, 7Department of Botany, The Islamia University of Bahawalpur
(Bahawalnagar Campus), Bahawalpur, Pakistan
RECEIVED
ACCEPTED
CITATION
Qureshi H, Anwar T, Mohibullah M,
Fatima S, Younas R, Habiba U, Malik L,
Hanif A and Iqbal M (2023), Paired plot
experiments to assess impact of invasive
species on native floral diversity
in Pakistan.
Front. Environ. Sci. 10:1037319.
doi: 10.3389/fenvs.2022.1037319
COPYRIGHT
© 2023 Qureshi, Anwar, Mohibullah,
Fatima, Younas, Habiba, Malik, Hanif and
Iqbal. This is an open-access article
distributed under the terms of the
Creative Commons Attribution License
(CC BY). The use, distribution or
reproduction in other forums is
permitted, provided the original
author(s) and the copyright owner(s) are
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publication in this journal is cited, in
accordance with accepted academic
practice. No use, distribution or
reproduction is permitted which does
not comply with these terms.
The threat of invasion is growing globally and endangers biodiversity. Exotic
invasive plants are putting a harm to the vegetation of Pakistan’s Pothwar
region, which is a biodiversity hotspot. In the current study, the effects of
Broussonetia papyrifera, Parthenium hysterophorus, Xanthium strumarium, and
Lantana camara on the local flora in the Pothwar area were examined. Two
categorical groups (invaded and non-invaded) were used in a dichotomized
experimental design to collect data. Using the software PRIMER-7 and IBM SPSS
v. 21, different diversity indices including Margalef’s index of species richness,
Shannon index of diversity, and Simpson index of dominance were measured
and compared between invaded and control plots. In comparison to the
experimental plots, the control plots had an average of more individuals and
diversity. On a multivariate scale, non-metric multidimensional scaling (nMDS)
and analysis of similarity (ANOSIM) revealed higher species richness in control
plots. The invasion effect of L. camara was the highest, followed by X.
strumarium, P. hysterophorus, and B. papyrifera.
KEYWORDS
invasion impacts, diversity indices, multivariate analysis, primer, conservation
Introduction
Biological invasion can be defined as “distribution of species to previously
inhospitable habitats, followed by their proliferation, spread, and persistence, as well
as detrimental impacts on biodiversity, health, and/or the economy”. One form of
biological pollution is biological invasion. Biopollution is the result of the influence of
non-native species on the ecosystem, including habitat degradation and modifications, the
spread of infections, competition with and extinction of native species, and population
genetic changes (Holm et al., 1991; Alpert, 2006). Exotic fauna, flora, insects and other
living things can all be categorized as biological pollutants, but because of their massive
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and APG IV 2016 was used to determine the right family name. The
data from five districts were pooled and presented as a whole.
biomass, plants offer the largest concern (Florece and Baguinon,
2011). Plants make up 32 of the top 100 invasive species
worldwide (Holzmueller and Jose, 2009). Global economic
activities including employment and travel are speeding up
the spread of invasive species (Pysek and Hulme, 2005).
Invasive plants diminish agricultural production, alter native
flora, endanger human and animal health, disturb ecosystem
processes (hydrology, soil nutrient composition), and spread
vector-borne diseases (Etana, 2013; Qureshi et al., 2014).
Invasive species are the second leading cause of biodiversity
loss after habitat degradation because of their ability to
outcompete and displace native species (Gaertner et al., 2009).
Seventy-three vascular plant species have been identified as
invasive in Pakistan (Qureshi et al., 2014). Some of the most
significant invaders in Pakistan include Parthenium
hysterophorus, Lantana camara, Broussonetia papyrifera,
Eucalyptus camaldulensis, Xanthium strumarium, Prosopis
juliflora, Eicchornia crassipes, Leucanea leucosephala, and Salvinia
molesta. The goal of this research was to see how much of an impact
the world’s top four invaders had on diversity indices in Pakistan’s
Pothwar region. Exotic invaders included P. hysterophorus, L.
camara, B. papyrifera, and X. strumarium.
Data analyses
With the use of the PRIMER-7 program, diversity indices such
as Margalef’s index of richness, Shannon-Weaver index of diversity,
and Simpson index of dominance were created and compared for
control and invaded plots. To verify if sampling was adequate in
each area, PRIMER was used to create rarefaction curves (Clarke
and Warwick, 2001). Both univariate and multivariate methods of
data analysis were applied, including the non-metric
multidimensional scaling method. Districts and invasion status
were taken into account when conducting ANOVA on the
diversity variables using SPSS. The significance of dissimilarities
among invasion and control plots between diversity catalogues for
each of the five districts was examined separately. The analysis of
species collections was carried out using PRIMER software and nonmetric multidimensional scaling in two to three dimensions with
invasion status as factor. We were able to determine the range of
clustering of sites and locations in response to invasion using
analysis of similarity (ANOSIM) and similarity percentage
(SIMPER). The mean difference of species between and within
sites is used by ANOSIM to calculate the global statistic. According
to SIMPER, the species that were most prevalent were also the ones
that contributed the most to the average community dissimilarity
(invaded and control plots).
Materials and methods
Research study area
Between the Indus and Jhelum Rivers, the Pothwar Zone is
located between latitudes 32.5°N and 34.0°N and longitudes 72°E
and 74°E. The cities of Jhelum, Islamabad, Attock, Rawalpindi,
and Chakwal are included in the Pothwar zone. The Pothwar area
has a harsh environment, with scorching summers and chilly
winters. In this location, the average annual rainfall is 812 mm.
The mean maximum temperature is in June (37°C) and the
coldest month being January (14–18°C).
Results
To gauge sample completeness, rarefaction curves, were
developed with the results indicating that sampling was
satisfactory (Figures 1A–D). For four of the analyzed invaders,
control plots had better average species diversity and richness per
plot (Figures 2A–D).
Comparison of diversity indices revealed significant
difference between districts and invasion status. In the case
of P. hysterophorus, control plots had an average of 6.033 ±
1.75 species. This was higher than the invasion plots (5.133 ±
1.83). In the control and invaded plots, a total of 181 and
154 individuals were recorded, respectively. Similarly,
abundance in the control and invaded plots differed by
3.7 ± 3.83. Diversity indices for L. camara indicated
variation across locations and invasion status. Control
plots harbored on average 13.90 ± 3.50 species. This was
by 1.734 ± 0.14 more than invaded plots. In total, 212 and
139 individuals were recorded in control and invaded plots
respectively. Similarly, abundance in control and invaded
plots differed by 2.3 ± 1.80. Control plots exhibited higher
values of species richness by a difference of 0.15 ± 0.41,
Shannon index of diversity by 0.20 ± 0.40 and Simpson index
Experimental design
Calculations and comparisons of diversity indices for selected
invaders were made in the five regions, individually (Attock,
Chakwal, Jhelum, Islamabad, and Rawalpindi). Six paired
vegetation plots, each measuring 3.16 m × 3.16 m, were randomly
selected from each district and were labelled as either invaded or
uninvaded. The “treatment” consisted of an invaded vegetation plot
(referred to as “invaded plot”) where the invader demonstrated
dominance, whereas the “control” consisted of an uninvaded
vegetation plot (referred to as a “non-invaded plot”) where the
invader displayed no dominance. Using the Flora of Pakistan
(https://www.eflora.com), the collected plant specimens were
identified from the selected plots. World flora online (http://www.
worldfloraonline.org/) was used to locate the right scientific names,
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FIGURE 1
A rarefaction curve illustrates the total number of species observed.
FIGURE 2
R = Margalef’s index of species richness; H’ = Shannon index of diversity; J’ = Species evenness; λ = Simpson index of dominance.
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FIGURE 3
Invasion status data multidimensional scaling (MDS) ordination and assessments of resemblance (ANOSIM) effects for the Pakistani region of
Pothwar (open symbols are for control, uninvaded plots, and closed symbols are for invaded plots).
Discussion
of dominance by 0.22 ± 1.27. In case of B. papyrifera,
comparisons of diversity indices showed differences in
invaded and control plots across sites. Control plots
harbored on average 9.07 ± 2.50 species. This was by
3.54 ± 2.08 more than invaded plots. In total 298 and
156 individuals were found in control and invaded plots
respectively. Similarly, abundance in control and invaded plots
differed by 2.97 ± 3.96 and the difference was significant. Control
plots exhibited higher values of species richness by a difference of
0.89 ± 0.53; Shannon index of diversity by 0.5 ± 0.29 and Simpson
index of dominance by 0.081 ± 0.042. For X. strumarium,
comparisons of diversity indices showed difference across sites
and invasion status. Control plots harbored on average 10.86 ±
2.50 species. This was by 2.86 ± 2.07 more than invaded plots and
the difference was significant. In total, 226 and 140 individuals
were found in control and invaded plots respectively. Similarly,
abundance in control and invaded plots differed by 2.97 ± 3.93;
species richness by 0.89 ± 0.53, Shannon index of diversity by
0.90 ± 0.29 and Simpson index of dominance by 0.18 ± 0.09.
Significant magnitude variations between the species
composition of the invaded and control plots were shown at
the multivariate scale by ordination (nMDS) and ANOSIM
(Figure 3).
The species that are primarily responsible for the average
variation between the control and occupied ploats were identified
by calculating similarity percentage. The top species in Table 1
that distinguish invaded plots from non-invaded plots are listed.
Frontiers in Environmental Science
P. hysterophorus is annual herb native to Mexico, the
southern United States, and South and Central America.
Due to its global presence, it is ranked among the top
10 worst weeds on the planet (Tamado and Milberg, 2000;
Khan et al., 2014; Qureshi et al., 2018). In the current study,
analyses of the diversity indices between the invaded and
control plots showed noticeable changes in the diversity of
the plants. These findings are in line with those of Riaz and
Javaid (2011), Shabbir and Bajwa (2007), Ojija et al. (2021)
and Ojija & Lutambi (2022) all of which report changes in the
vegetation composition of the invaded plots. Crop output,
biodiversity, and human and animal health are all impacted by
parthenium (Shabbir, 2013). By displacing native species and
forming massive monocultures, P. hysterophorus significantly
alters natural habitats. Using the ordination (nMDS) and
ANOSIM techniques, significant differences were identified
between invaded and control plots at each of the five study
locations, but Jhelum revealed the most. According to
Upadhyay et al. (2013), P. hysterophorus plants have been
found to thrive in more salinized soil, which is detrimental to
many native plant species. Because of this, Jhelum’s salinityrich soil may be to blame for the increasing invasion impacts
there. When compared to control plots, invading plots had
lower levels of species dominance, according to SIMPER
analysis.
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TABLE 1 SIMPER analysis of district-level data for P. hysterophorus invaded and control sites
Average dissimilarity = 60.14%
Average abundance
Control
Invaded
Av. Diss
Diss./SD
Contribution (%)
Poa annua
2.94
0.00
2.38
8.06
3.95
Lathyrus aphaca
0.00
2.69
2.18
5.82
3.63
Solanum miniatum
2.47
0.00
2.00
7.85
3.32
Ricinus communis
2.19
0.00
1.77
2.05
2.95
Convolvulus arvensis
1.80
1.79
1.49
1.32
2.48
Taraxacum officinale
1.77
0.00
1.40
2.07
2.32
Rosa damascena
1.82
0.18
1.38
1.41
2.29
Tribulus terrestris
1.62
0.00
1.31
2.03
2.18
Fumaria indica
2.35
1.15
1.31
1.55
2.18
Tephrosia purpurea
0.00
1.63
1.29
1.36
2.15
Species
District-level SIMPER analysis for L. camara invaded and control sites. Average dissimilarity = 65.56%
Average abundance
Control
Invaded
Av. Diss
Diss/SD
Contribution (%)
Stellaria media
3.04
1.71
1.38
7.99
2.10
Oxalis corniculata
2.98
0.00
1.35
9.94
2.06
Cynodon dactylon
2.81
1.82
1.27
9.48
1.94
Digitaria ciliaris
2.74
0.00
1.24
6.40
1.89
Malva parviflora
2.70
0.00
1.22
7.69
1.86
Croton tiglium
2.65
1.77
1.20
9.38
1.83
Eclipta prostrata
2.65
0.18
1.19
12.44
1.82
Clematis grata
2.54
1.62
1.15
6.88
1.76
Chenopodium album
2.46
2.35
1.12
4.51
1.71
Calotropis procera
2.43
0.01
1.11
5.98
1.69
Species
District-level SIMPER analysis for B. papyrifera invaded and control sites.Average dissimilarity = 57.19%
Average abundance
Invaded
Control
Av. Diss
Diss/SD
Contribution (%)
Tribulus terrestris
2.90
0.00
1.63
7.24
2.85
Malvastrum coromandelianum
2.57
0.00
1.46
4.14
2.55
Cynodon dactylon
2.44
0.00
1.36
1.91
2.38
Silybum marianum
0.81
2.69
1.12
1.54
1.97
Calotropis procera
2.02
0.00
1.12
1.89
1.96
Datura innoxia
1.98
0.00
1.04
1.33
1.82
Species
(Continued on following page)
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TABLE 1 (Continued) SIMPER analysis of district-level data for P. hysterophorus invaded and control sites
Average dissimilarity = 60.14%
Average abundance
Control
Invaded
Av. Diss
Diss./SD
Contribution (%)
Digeria muricata
1.94
0.00
1.02
1.36
1.79
Kochia indica
1.40
3.12
1.01
1.22
1.77
Desmostachya bipinnata
2.96
1.25
1.00
1.29
1.74
Swertia paniculata
2.30
0.85
0.97
1.53
1.70
Species
District-level SIMPER analysis for X. strumarium invaded and control sites.
Average dissimilarity = 53.90%
Average abundance
Control
Invaded
Av. Diss
Diss/SD
Contribution (%)
Solanum nigrum
2.93
1.03
1.73
5.58
3.21
Cynodon dactylon
2.94
1.55
1.72
9.37
3.21
Parthenium hysterophorus
2.69
1.61
1.58
9.91
2.93
Dodonaea viscosa
2.59
1.35
1.51
4.16
2.81
Tamarix aphylla
2.94
1.51
1.43
2.33
2.66
Ajuga bracteosa
2.41
1.34
1.42
5.80
2.63
Rumex dentatus
2.16
1.48
1.25
2.17
2.32
Typha domingensis
2.70
1.44
1.13
2.57
2.10
Withania somnifera
1.95
0.90
1.12
3.28
2.09
Lantana camara
1.89
0.52
1.11
1.95
2.06
Species
Values represent average abundance ranking (rare, common, very common, >4-dominant, and so forth).
The rankings of average profusion (rare, common, extremely common, >4-dominant, and so forth) are represented by the values.
the invading and control plots. The most severely impacted by
the L. camara invasion were found to be herbs.
The dioecious, deciduous Broussonetia papyrifera is a common
tree in tropical and subtropical areas and is endemic to East Asia, is
one of Pakistan’s six deadliest plant invaders because of its detrimental
effects on local vegetation (Malik and Hussain, 2007). B. papyrifera
has a number of harmful consequences on the environment and
people, including a decrease in biodiversity, poor effects on
anthropological health, obstruction of city sewer systems, and a
rise in caw inhabitants that spread seeds (Huston 1979; Hsu et al.,
2008). The species groupings of the invasion and control plots showed
notable magnitude of differences when employing the ordination
(nMDS) and ANOSIM techniques. Invaded plots had lower levels of
species dominance than control plots.
The annual herb X. strumarium is native to North and South
America. It has turned into a common weed in orchards,
L. camara is a medium-sized, fragrant Neotropical perennial
shrub. It has spread to more than 60 countries and is ranked
among the ten worst weeds (Qureshi et al., 2014). This study
found that there had been substantial changes in the study area
based on diversity indices comparisons between invaded and
control plots. These results support past research on this invasive
weed, which found that the invader has a considerable impact on
natural resources (Shabbir and Bajwa, 2007; Riaz and Javaid,
2010; Riaz and Javaid, 2011). The values for diversity indices of
the control and invaded plots were considerably different, as
shown by the ordination (nMDS) and ANOSIM approaches. The
alteration was substantial across the five study sites. The main
invasive plant in the Attock region was previously recognized as
L. camara along with two other species, Prosopis juliflora and
Xanthium strumarium (Malik and Husain, 2006). SIMPER
analysis revealed a total dissimilarity of 65.56 percent between
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10.3389/fenvs.2022.1037319
invaders assessed, posing a risk to plant diversity in invaded
areas. Strong control methods, comprising the use of verified
natural control managers, are immediately essential to contest
this plant in Pakistan.
cultivated areas, and inhospitable surroundings (Hashim and
Marwat, 2002). Ordination and ANOSIM showed that the
invaded and control plots’ diversity indices differed
significantly from one another. X. strumarium invasion was
previously recognized as the most invasive plant in the
Rawalpindi district, along with two other species, Prosopis
juliflora and Lantana camara (Malik and Husain, 2006). The
SIMPER analysis found that there were overall changes of
53.90 percent between the invaded and control plots.
Plants’ ability to successfully colonize unnatural surroundings,
quick growth and reproduction, short lifespan, mass seed
production, vegetative proliferation, early flowering and sowing,
phenology that differs from inhabitants, and pest and infection
tolerance are all elements that help them to be invaders. Secondary
metabolites have recently been implicated in the ecological
dominance of invasive species (Balezentiene, 2015). For resources
like space, light, and nutrients, invasive plants outcompete endemic
species (Tilman, 1997). It is believed that the absence of evolutionary
connections between native and invasive species causes invasion.
Data availability statement
The original contributions presented in the study are
included in the article/supplementary material, further
inquiries can be directed to the corresponding author.
Author contributions
Design, experiments, analysis-HQ, editing-TA, helped in
field visits-MM, SM and RY, helped in formal analysis-UH,
LM and AH, helped in writing-MI.
Conflict of interest
Conclusion
The authors declare that the research was conducted in the
absence of any commercial or financial relationships that could
be construed as a potential conflict of interest.
Plant invasions cause huge ecological and economic
imbalances by reducing species diversity, changing indigenous
population composition, and disrupting ecosystem processes in
new places. Invasive species research has previously
demonstrated that invasion impacts are complicated, and that
they can always vary community role and organization, as well as
trigger local extinction and fluctuations in environmental
procedures. Alien plant invasions change ecosystem dynamics
and structure on a large scale, which can significantly affect
ecosystem services. The current study’s drop in ecological
diversity indices between attacked and control locations
showed that floral groups were little resilient as a result of the
Publisher’s note
All claims expressed in this article are solely those of the
authors and do not necessarily represent those of their affiliated
organizations, or those of the publisher, the editors and the
reviewers. Any product that may be evaluated in this article, or
claim that may be made by its manufacturer, is not guaranteed or
endorsed by the publisher.
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