Stage-specific ploidy level variations in invasive species in comparison to rare endemics in Kashmir Himalaya

Journal Pre-proof Stage-specific ploidy level variations in invasive species in comparison to rare endemics in Kashmir Himalaya Mudasir A Dar, Gowher A Wani, Zafar A Reshi, Abdul Aziz Al-Qarawi, E.F. Abd Allah, Manzoor A Shah

PII:

S0367-2530(19)30529-8

DOI:

https://doi.org/10.1016/j.flora.2019.151525

Reference:

FLORA 151525

To appear in:

Flora

Received Date:

24 September 2018

Revised Date:

23 November 2019

Accepted Date:

1 December 2019

Please cite this article as: Dar MA, Wani GA, Reshi ZA, Al-Qarawi AA, Abd Allah EF, Shah MA, Stage-specific ploidy level variations in invasive species in comparison to rare endemics in Kashmir Himalaya, Flora (2019), doi: https://doi.org/10.1016/j.flora.2019.151525

This is a PDF file of an article that has undergone enhancements after acceptance, such as the addition of a cover page and metadata, and formatting for readability, but it is not yet the definitive version of record. This version will undergo additional copyediting, typesetting and review before it is published in its final form, but we are providing this version to give early visibility of the article. Please note that, during the production process, errors may be discovered which could affect the content, and all legal disclaimers that apply to the journal pertain. © 2019 Published by Elsevier.

Ploidy in relation to plant invasions

Stage-specific ploidy level variations in invasive species in comparison to rare endemics in Kashmir Himalaya Mudasir A Dar1, Gowher A Wani1*, Zafar A Reshi1, Abdul Aziz AlQarawi2, Abd_Allah E. F2, Manzoor A Shah1

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Department of Botany, University of Kashmir, Srinagar-190 006, Jammu & Kashmir, India

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Department of Plant Protection, College of Food and Agricultural Sciences, King Saud University, Riyadh

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*Corresponding author: [email protected]; +91-7006011834

Highlights

Abstract

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Our results support a positive relationship between ploidy status and species invasiveness. Invaders are largely polyploids while endemics tend to be diploids. However, early stage (stage II) invaders and endemics show similar levels of diploidy. The ploidy status of invasive species can yield useful insights for biodiversity managers.

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Despite the recently recognized link between ploidy level and species invasiveness, disentangling ploidy variations throughout the various stages of invasion still is an open

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question. Therefore, our aim was to investigate the variations in the ploidy level of alien Kashmir Himalayan plant throughout different stages of invasion and to compare those variations with the ploidy levels of 112 rare endemics. Ploidy level data was derived from an extensive literature review and web-based sources. The equality of proportions test was used to assess the relationship between ploidy status and species invasiveness or rarity/endemicity. We used Pearson’s product-moment correlation coefficient to test the relationship between ploidy level and diversification among some of the most widespread alien plant families. 1

Ploidy in relation to plant invasions Results showed a greater preponderance of polyploidy in invasive than in rare endemic species, which were mostly diploids. Regression analysis of 309 alien plant species showed that the proportion of polyploids increases with the stage of invasion, from stage II to stage V. Our results suggest a positive relationship between ploidy status and invasiveness. We emphasize the predictive value of these variations, as our model suggests that the 32 stage II alien polyploids seem more likely to become future invaders in Kashmir Himalaya than the 46 stage II diploids. Appropriate management strategies could be put in place early enough to prevent further damage from these potentially dangerous species.

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Keywords: Alien species. Endemics. Polyploids. Diploids. Kashmir Himalaya. Plant invasion.

Introduction

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What makes a species rare or widespread is a rather challenging question confronted by

conservationists and evolutionary biologists. In view of the rapid spread of some invasive

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species at the cost of native and rare endemic species, untangling the underlying evolutionary mechanisms of species invasiveness and range shift becomes even more important. While most of the alien species remain relatively confined in their introduced ranges, a subset of

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these species become invasive and generally exert strong negative impacts on native species diversity in invaded regions (Shah et al., 2014). The role of population genetic structure and

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climatic variables on the impact of invasive species have recently been reported by Rosche et al. (2019). On the other hand, whether species undergo transition from diploid to polyploid status upon introduction from native to non-native ranges has also recently struck some invasion biologists (Meyerson et al., 2016). It has been suggested that range expansion by invasive species leads to variation in genetic diversity in the invaded range, and often causes

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species transition from diploidy to polyploidy (Lachmuth et al., 2010; Pandit et al., 2011). It would be worth investigating whether such variations in the level of ploidy across the range of some species are related to their ecological impacts. Amongst various factors contributing to species invasiveness, the role of ploidy status is substantiated by some recent quantitative data-based studies (Pandit et al., 2006, 2011; Wani et al., 2018). However, mere correlative inferences about the links between species invasiveness and polyploidy are not enough, and it is probably more important to uncover 2

Ploidy in relation to plant invasions how species mange to do so. Polyploidy predisposes species to maintain higher levels of genetic diversity and to experience reduced inbreeding depression compared to their diploid ancestors (Soltis and Soltis 2010). Furthermore, polyploidy also generates novel species or haplotypes with broader ecological amplitude, and can modify morphological, phenological, physiological and even ecological attributes (Levin, 1983) that may contribute to their invasiveness under novel circumstances in the non-native range (Leitch and Leitch, 2008). Polyploidy has also been linked to the transition of plants to asexual reproduction, a hallmark of invasive species, and influences seed germination and dormancy; it also increases resistance to pathogens, making it easier for them to outcompete native plants, and has

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substantial ecological and genetic consequences for their invasiveness (Templeton and Levin, 1979; Beest et al., 2012).

How traits affect the population status of plant species has long been regarded

important in the conservation of rare endemics and in the management of noxious invaders

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(Fisher, 2004). An over-representation of invasive traits in most cross species comparisons is expected to be valuable in identifying potential invaders and in reducing the costs associated

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with managing alien invasive plants at different stages of invasion (Pysek and Richardson, 2010). There are some strong evidences backing the association of invasiveness with both smaller genome size and higher ploidy levels (Pandit et al., 2011). In addition to exhibiting

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rapid range expansions (Levin, 1983; Hull Sanders et al., 2009; Treier et al., 2009) polyploids are over-represented in invasive alien plants compared to native (endemic) (Verlaque et al.,

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2002; Pandit et al., 2006) or to rare plants (Pandit et al., 2006; Pandit et al., 2011). A strongly positive correlation between the risk of extinction and increased DNA C values also suggests the role of diploidy in making a species rare (Vinogradov, 2003). Despite the aforementioned studies, there has been hardly any effort to unravel the role of ploidy level variation in a stage specific manner along introduction-naturalization-invasion continuum.

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The alien vascular flora of Kashmir Himalaya was recently compiled and all the

species were characterized on the basis of different invasion stages (Khuroo et al., 2008; Shah and Reshi 2014) following a model proposed by Colautti and MacIsaac (2004). Starting from resident species in a potential donor region (Stage 0), carried through different transport vectors (Stage I), and released into the introduced region (Stage II), the species may become localized and numerically rare (Stage III), widespread but rare (Stage IVa), localized but dominant (Stage IVb) or widespread and dominant (Stage V). Since Stage II species are at the 3

Ploidy in relation to plant invasions initial stage of introduction and Stage V ones are highly invasive, the former require a focus on timely prediction and early warning (and eventually eradication) and the latter need urgent and alternative management practices to prevent further spread or damage. We hypothesized whether the Colautti and MacIsaac model can be used to identify potential plant invaders attending to their ploidy level data. One of the surrogates to assess the relationship between polyploidy and invasiveness is to compare the ploidy status of broad range invasive species to narrow range endemic ones (Pandit et al., 2006, 2011). In view of the lack of information on whether alien species at different stages of invasion exhibit any significant variation in their ploidy levels, the specific questions addressed in this study were (a) what is the extent of

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ploidy level variations in alien species in Kashmir Himalaya and how does it vary along different stages of invasion? (b) do rare endemics exhibit similar or different variation patterns in ploidy level compared to invasive aliens?

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Materials and Methods

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Study area

The study was carried out in the Kashmir region of Northwestern Himalaya, a part of the

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Himalayan biodiversity hotspot. The region extends from 32o20` to 34o50` North and 73o55` to 73o35` East, covering an area of about 15,948 km2. Almost 64 % of this area is comprised of mountains with a deep elliptical bowl-shaped valley surrounded on all sides by high

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mountain ranges; the PirPanjal range of the Lesser Himalaya in the south and south-west, and the Zaniskar range of the greater Himalaya in the north and north-east (Hussain, 2002). Owing to its colonial past, proximity to the erstwhile silk route and promotion as an important tourist destination, the region has witnessed large-scale introduction of alien species over the years. A range of studies have been carried out on different aspects of plant

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invasions in the region (see for instance Shah and Reshi, 2014; Shah et al., 2008, 2010, 2015) but there hasn’t been any attempt to investigate ploidy level variations in the alien flora of the region except the one by Wani et al. (2018) on some aquatic alien species. Target flora The target flora of the present study included both alien and rare endemics of the Kashmir Himalaya. Endemic species (i.e., species with restricted distribution) have often been found 4

Ploidy in relation to plant invasions to a limited geographical area irrespective of overall richness of taxa (Heywood, 1995). These narrow endemic plants are strictly restricted to Kashmir Himalaya. Narrowly endemic species are rare, and therefore potentially threatened (ISIK, 2011). Out of the 571 reported alien plant species (Khuroo et al., 2007) and 153 endemics (Dar et al., 2012) in the region, data were collected on the ploidy status of 390 alien species and 112 endemic species during the present study. This whole data set comprising 502 species is quite typical of both alien and endemic categories due in part to the fact that species were selected

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randomly, subject to availability of ploidy level data from different sources.

Data sources and collection

Data on ploidy levels of the investigated species were collected from different primary published sources including articles and reports published in peer reviewed scientific

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journals, standard reference books, some biological abstracts, besides some unpublished

sources. Some web based data sources such as BIOFLOR (Klotz et al., 2002), plant CDNA

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values / Royal Botanic Gardens Kew Database (Bennett and Leitch, 2005) http://data.kew.org/cvalues/CvalServlet), IPCN

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(http://mobot.mobot.org/W3T/Search/ipcn.html), Web of Science, etc. were also consulted. Data on the ploidy level and chromosome number of each endemic species were obtained from Jee et al. (1989). Regarding the ploidy level, two aspects were taken into consideration:

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(a) Chromosome number represented by 2n and (b) the ploidy category i.e., either diploid or polyploid, represented respectively by asterisk (*) and nx (x=basic chromosome number). Species with more than one ploidy level, i.e., with both diploids and polyploids, were treated as mixed ploids. The data on ploidy level was obtained through extensive survey of published

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literature and web-based sources.

Data on other ecological attributes of species such as stage of Invasion were obtained from other published sources (Khuroo et al., 2008; Shah and Reshi, 2014; Wani et al., 2018). Data analysis

The attribute of interest to us in the present investigation was ploidy level category (i.e. either diploid or polyploid). As ploidy levels can’t be averaged to obtain species specific values, 5

Ploidy in relation to plant invasions these were treated as categorical variables in order to calculate dissimilarities. The ploidy levels were therefore weighted by 1/ (number of ploidy levels). For species with more than one ploidy level, the same total weight was allocated for each species, and we assumed that all ploidy levels occur with equal frequency. For our analysis of the relationship of ploidy level with invasiveness and endemism / rarity, we performed a number of statistical tests in R (version 2.15.1). We tried to find out the relation between species status (alien invasive vs. alien non-invasive) and ploidy level, by taking their respective stages of invasion as an indicator of invasiveness or non-invasiveness. For the general comparison between alien (including both alien invasives as well as alien non-invasives) and native / endemic plant

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species, we first compared the relative proportion of diploids and polyploids within each group, using the test of equality of proportion. Then, we attempted a cross comparison of alien diploids with endemic diploids and alien polyploids with endemic polyploids,

respectively. Finally, we tested the relationship of ploidy level with species richness

(taxonomic diversification) among the five most widespread alien plant families in the study

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region, using the Pearson’s product-moment correlation coefficient.

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Results

Data were generated on the ploidy level of 390 alien plant species belonging to 255

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genera and 76 families of flowering plants in Kashmir Himalaya (Appendix I). Out of 390 alien plant species, 200 (50.77%) were found to be diploid, 166 (43.08%) polyploid and the remaining 24 (6.15%) were of mixed-ploidy, i.e. more than one ploidy level. Data were also

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obtained on the ploidy level of 112 endemic plants (Appendix II), wherein 82 (73%) were found to be diploids and the other 30 (27 %) showed polyploidy. Alien plants ranged from diploid to 18-ploid while endemics spanned over a narrower range as 99.1 % of them ranged from diploid to octaploid and only one species was 12x.

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About 8% of intraspecific ploidy polymorphism occurred among alien plants and no

such polymorphism was found among the endemics. Among the alien plants, only 3.33% of the ploidy levels were odd numbered, and 92.56% were equal to or less than octaploid. Species having ploidy levels above 8x represented just 1.28%, while the remaining 6.15% were of mixed-ploidy. In the case of the endemics, only 4.46% of the ploidy levels were odd numbered, and 99.1% were equal to or less than octaploid. Only 0.9% of the endemics had ploidy levels above 8x. 6

Ploidy in relation to plant invasions Out of 390 alien plant species, 24 were reported as mixed-ploids (i.e., both diploids and ployploids), and were excluded from analytical calculations. Of the remaining 366, invasion stage data was available for 309 species. Comparison of diploids and polyploids with the test of equality of proportions revealed that both alien and endemic plants have significantly higher proportions of diploids than polyploids (aliens x2=5.9508; P < 0.05; endemics x2 = 46.446; P < 0.005, Table 1). But a comparison of the relative proportion of alien diploids with endemic diploids, and alien polyploids with endemic polyploids, showed that aliens plants are disproportionately more polyploid than endemic ones while, conversely, endemics are disproportionately more likely to be diploid than aliens (x2=11.469; P < 0.005;

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Table 1). The relative proportion of diploids showed a decreasing trend, and that of polyploids showed an increasing one, with the stage of invasion in these 309 alien plants (Table 2). Invasion stage II with 46 diploids and 32 polyploids constituted the highest relative

proportion of diploids and the lowest relative proportion of polyploids while invasion stage V

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(23 diploids and 35 polyploids) showed the second lowest relative proportion of diploids and the highest relative proportion of polyploids. Comparison of the relative proportion of

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diploids and polyploids belonging to different stages of invasion (Table 2) revealed some interesting patterns. For example, diploids and polyploids are evenly represented at invasion

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stage IVa, but the stages preceding and succeeding it show higher and lower proportion of diploids, respectively. Regression analysis carried out with the aforementioned 309 alien plant species showed that the relative proportion of polyploids increased with the stage of

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invasion from stage II (alien plants introduced into their non-native region) to stage V (alien plants become widespread and dominant). The relationship was separately tested for polyploids (Fig. 1; R2 = 0.9289; P < 0.01) and diploids (R2 = 0.8991; P < 0.01) using a linear regression model.

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Finally, the relationship of ploidy status with species richness (or taxonomic

diversification) within five of the most widespread alien plant families (Table 3) showed a positive correlation between percent polyploidy and species richness (r = 0.8664). Family Poaceae, with highest (47) species richness, was found to have the highest (61.70 %) percentage of polyploidy, while polyploidy in Asteraceae, Brassicaceae, Fabaceae, and Rosaceae was 37.5%, 36%, 33.33%, and 26.32%, respectively. Poaceae also showed the highest percentage (12.77 %) of mixed-ploids. 7

Ploidy in relation to plant invasions Discussion In view of the limited information available on the ploidy status of invasive plants in the Himalayan region, this study comes to fill a gap in our knowledge as it involved 440 plant species (390 aliens and 112 endemics), and may does have potentially relevant management and conservation implications. The most striking result is that invasive species are largely polyploids while endemics tend to be mostly diploids. These results are in agreement with previous studies (Pandit, 2006; Pandit et al., 2006, 2011; Lowry and Lester, 2006; Wani et al., 2018) providing new support to a connection between ploidy level and species invasiveness. The relatively high proportion of diploids found in the rare endemic species is

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also in agreement with the global analysis by Pandit et al. (2011) who reported that while most of the rare endemics have a diploid genetic makeup, invasive alien plants tend to have

high chromosome counts, besides of being polyploids. In another study from the Indian subcontinent, a significant fraction of diploid, rather than ployploid plants, were found to be rare and the chances of endangerment or rarity seemed negatively correlated to increased

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chromosome numbers (Pandit, 2006).

The rarity of plant species has been correlated to decreased levels of genetic diversity

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(e.g. Karron, 1987; Sherman-Broyles et al., 1992), presumably due to the inbreeding and genetic drift inherent to small, isolated populations. Other studies (Pandit, Tan and Bisht,

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2006) also lend support to our results that highly invasive plants are polyploids. Though invasiveness and polyploidy have long been thought to be linked (Hodgson, 1987; Soltis and Soltis, 2000; Lee, 2002), the links between diploidy and species rarity have been recognized

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more recently (Lowry and Lester, 2006). Nonetheless, further empirical support is required to strengthen the basis of such relationships. Ploidy variations need to be better understood in concert with the other morphological and ecological attributes related to species invasiveness. Our stage-based analysis of the alien flora of Kashmir Himalaya showed that polyploids commonly belong to the most advanced stage of invasion (stage V) while diploids are largely

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non-invasive. For instance, diploids are similarly common in stage II aliens as in endemics, suggesting a possible role of ploidy status in their restricted distribution. These results agree with our recent studies (Wani et al., 2018) on 118 alien aquatic species of Kashmir Himalaya. The relatively greater percentage of polyploidys found at higher stages of invasion may possibly attributed to their increased resistance to pests, pathogens, nutrient stress, genetic drift, altered physiology and comparatively wider range of ecological tolerance (Stebbins, 1985; Levin, 1983; Beest et al., 2012; Roche et al., 2016, 2017; Nagy et al., 2017). 8

Ploidy in relation to plant invasions The substantial difference in the proportion of diploids and polyploids between alien and endemic plants found in this study indicates that cytology may play a role in determining the population status of a species, a may have useful conservation implications (Kunin and Gaston, 1993). Earlier cytogeographic studies (Janaki Ammal, 1950, 1954; Dhar, 2002) on genera such as Rhododendron or Camelia in India have also indicated the role of ploidy status in influencing species geographic ranges. It is worth mentioning that the availability of modern cytogenetic tools, such as flow cytometry, have greatly helped researchers to screen relatively large number of species for the ploidy status (Ainouche and Jenczewski, 2010; Soltis et al., 2010) in a rather rapid and more affordable way (Kron et al., 2007). Variation in

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the content of nuclear DNA and ploidy polymorphism between species remains a subject of debate. Results from our study indicate some level of intraspecific ploidy polymorphism in

alien plant species, but not so in endemic plants. As recently reported by Wani et al. (2018), intraspecific ploidy polymorphism deserves further investigations together with its implications for invasiveness. While Weber (2003) reported high levels of ploidy

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polymorphism among the world’s worst 55 invasive species, ours is one of the few studies

reporting that ploidy polymorphism is largely absent in endemic plants. The lack of ploidy

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level variations and the preponderance of diploidy among endemics, together with other factors, probably restrict their range expansion. On the other hand, ploidy heterogeneity may

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have predisposed alien plants for the colonization of large heterogeneous areas. Nearly half of the species of flowering plants mainly owe their origin to polyploidy

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(Darlington, 1946). Our preliminary results also indicate that polyploids seem taxonomically more diverse. The relationship between ploidy level and taxonomic diversification among the six most widespread alien plant families in the Kashmir region revealed a positive correlation between species richness and percentage of polyploidy. Thus, using ploidy level as an estimate of species richness is a step ahead in understanding the causes of diversification, at

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least within these six plant families. Moreover, our results contribute to the perception that polyploidy may be associated with an increased species richness (Petit and Thompson, 1999; Otto and Whitton, 2000). Polyploidy can also be related to rapid speciation events (Stebbins, 1950; Levin, 1983). As a consequence, frequency of polyploidisation events in plant genera and families may be of particular importance in their taxonomic diversification. The wide ecological range of our six target families might probably be due to the presence of

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Ploidy in relation to plant invasions polyploids that occur in different environments in contrast to their diploid counterparts that possibly occur in more selected environments, as proposed by Rosenzweig (1995).

Conclusion The present study supports the link between polyploidy and species invasiveness. Stage-based characterization of alien flora as a function of ploidy level variations may potentially help biodiversity managers to identify alien plant species more likely to become future invaders, and to prioritize them for different management strategies. Moreover, the ploidy status of plant species might be of some use for determining their current status and

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future distribution. Hence, gaps in the cytological data of floras need to be filled to draw potentially useful inferences with conservation implications. The precision of these models may significantly increase if future studies incorporate a molecular genetics and

phylogenetics perspective. Since invasive species are generally diploid in their native range

but polyploids in their non-native ranges (Lafuma et al., 2003; Trier et al., 2009; Rosche et al.

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2017), an interesting future study would be to assess whether, and how much, alien species of

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Kashmir Himalaya vary in their ploidy status across native and non-native ranges.

Acknowledgement

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Thanks are due to the Visiting Professor Program of the Ministry of Higher Education King Saud University, Vice Rectorate for Graduate Studies and Scientific Research , under which

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MAS was a visiting professor at KSU.

Conflict of interest

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The authors declare that they have no conflict of interest.

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Shah, M.A., Reshi, Z., Rashid, I., 2008. Mycorrhizal source and neighbour identity differently influence Anthemis cotula L. invasion in the Kashmir Himalaya, India. Appl. Soil Ecol. 40, 330−337. Shah, M.A., Reshi, Z., Rasool, N., 2010. Plant invasion induces shift in Glomalean spore diversity. Tropical Ecol. 51(2S), 317−323.

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Shah, M.A., Reshi, Z.A., 2014. Characterization of alien aquatic flora of Kashmir Himalaya: implications for invasion management. Tropical Ecol. 55(2),143−157.

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Sherman-Broyles, S.L., Gibson, J.P., Hamrick, J.L., Bucher, M.A., Gibson, M.J., 1992 Comparisons of allozyme diversity among rare and widespread Rhus species. Syst. Bot. 17, 551–559.

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Soltis, D.E., Buggs, R.J.A., Doyle, J.J., Soltis, P.S. 2010. What we still don’t know about polyploidy. Taxon 59, 1387−1403. Soltis, P.S., Soltis, D.E., 2000. The role of genetic and genomic attributes in the success of polyploids. Proceedings of the National Academy of Sciences of the United States of America 97, 7051–7057.

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Stebbins, G.L., 1950. Variation and evolution in plants. New York: Columbia University Press. Stebbins, G.L., 1985. Polyploidy, hybridization, and the invasion of new habitats. Annals of the Missouri Botanical Garden 72, 824–832.

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te Beest, M., Le Roux, J.J., Richardson, D.M., Brysting, A.K., Jan Suda Kubesova, M., Pysek, P., 2012. The more the better? The role of polyploidy in facilitating plant invasions. Ann. Bot. 109,19–45. Templeton, A.R., Levin, D.A., 1979. Evolutionary consequences of seed pools. American Naturalist 114, 232−249. Treier, U.A., Broennimann, O., Normand, S., Guisan, A., Schaffner, U., Steinger, T., Muller-Scharer, H., 2009. Shift in cytotype frequency and niche space in the invasive plant Centaurea maculosa. Ecology 90, 1366−1377. Verlaque, R., Aboucaya, A., Fridlender, A., 2002. Invasive alien flora of France: ecology, life-forms and polyploidy. Botanica Helvetica112, 121 – 136.

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Ploidy in relation to plant invasions Vinogradov, A.E., 2003. Selfish DNA is maladaptive: evidence from the plant. Red List.Trends in Genetics 19, 609−614. Wani, G.A., Shah, M.A., Reshi, Z.A., Dar, M.A., 2018. Polyploidy determines the stage of invasion; clues from Kashmir Himalayan aquatic flora. Acta. Physiol. Plant.https://doi.org/10.1007/s11738-018-2629-4.

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Weber, E., 2003. Invasive plant species of the world: a reference guide to environmental weeds. CABI Publishing, Wallingford.

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Percentage of polyploids

Ploidy in relation to plant invasions

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Fig. 1: Relationship between the stages of invasion with the percentage number of polyploids in some alien plant species.

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Ploidy in relation to plant invasions Table 1 Proportion of diploids and polyploids in alien and native/endemic plant species of Kashmir Himalaya. x2

Ploidy

Aliens

Natives

Proportion of Ploidy levels in aliens

Proportion of ploidy levels in natives

Diploids

200

82

0.55

0.73

11.469

<0.005

Polyploids

166

30

0.45

0.27

11.469

<0.005

X2

5.95

46.44

P

<0.05

<0.005

366

112

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Total

P

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Ploidy in relation to plant invasions Table 2 Distribution of alien plant species of different ploidy levels belonging to different stages of invasion in the Kashmir Himalaya. (Data within parentheses gives the relative proportion of different ploidy levels). Percentage of Diploids d

Percentage of Polyploids p

Percentage of Mixed-Ploidy

Total

1. II

46 (56.09)

32 (39.02)

4 (4.89)

82 (26.54)

2. III

34 (50.00)

27 (39.71)

7 (10.29)

68 (22.00)

3. Iva

21 (45.65)

21 (45.65)

4 (8.70)

46 (14. 89)

4. IVb

19 (36.54)

28 (53.85)

5 (9.61)

52 (16. 83)

5. V

23 (37.70)

35 (57.38)

3 (4.92)

61(19.74)

Total

142 (45.95)

144 (46.60)

23 (7.44)

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Stage of invasion*

(Colautti and MacIsaac, 2004, CM model)* R2 = 0.8991; P < 0.01

p

R2 = 0.9289; P < 0.01

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Ploidy in relation to plant invasions Table 3 Relationship of ploidy status with species richness in the most widespread alien plant families in Kashmir Himalaya. Species richness

% diploidy

% polyploidy

% mixed-ploidy

1. Poaceae

47

25.53

61.70

12.77

2. Asteraceae

40

55.00

37.50

7.50

3. Brassicaceae

25

52.00

36.00

12.00

4. Fabaceae

21

66.67

33.33

0.00

5. Rosaceae

19

68.42

26.32

5.26

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Family

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