
Figure 1.
Location of plots studied in the forests of Morni Hills, Haryana (India).

Figure 2.
Climograph showing the monthly average temperature and rainfall of Morni Hills, Panchkula (Source: www.worldweatheronline.com).
Table 1.
Summary of invasive alien plant species encountered during the study.
| S.N. | Name | Family | Habit | Nativity | Longevity | Flowering Phenology |
|---|---|---|---|---|---|---|
| 1 | Ageratum conyzoides L. | Asteraceae | Herb | Tropical America | Annual | Dec-May |
| 2 | Ageratum houstonianum Mill. | Asteraceae | Herb | Tropical America | Annual | May-Nov |
| 3 | Alternanthera pungens Kunth | Amaranthaceae | Herb | Tropical America | Perennial | Mar-Oct |
| 4 | Argemone mexicana L. | Papaveraceae | Herb | Tropical south America | Annual | Jan-Dec |
| 5 | Bidena pilosa L. | Asteraceae | Herb | Tropical America | Annual | Jan-Dec |
| 6 | Cardamine hirsuta L. | Asteraceae | Herb | Tropical America | Annual | Mar-Sept |
| 7 | Cassia occidentalis L. | Caesalpiniaceae | Shrub | Tropical south America | Annual | Jan-Dec |
| 8 | Calotropis procera (Ait.) R.Br. | Asclepiadaceae | Shrub | Tropical Africa | Perennial | Jan-Dec |
| 9 | Celosia argentea L. | Amaranthaceae | Herb | Tropical Africa | Annual | Sept-Jan |
| 10 | Chromolaena odorata (L.) R.M. King & H. Rob. | Asteraceae | Herb | Tropical America | Perennial | Dec-Mar |
| 11 | Cirsium arvense (L.) Scop. | Asteraceae | Herb | Europe | Annual | Mar-Aug |
| 12 | Croton bonplandianum Baill. | Euphorbiaceae | Herb | Temperate south America | Annual | Jan-Dec |
| 13 | Echinochloa colona (L.) Link. | Poaceae | Herb | Tropical south America | Annual | Jun-Sept |
| 14 | Emilia sonchifolia (L.) | Asteraceae | Herb | Tropical America | Annual | Jul-Oct |
| 15 | Euphorbia heterophylla L. | Euphorbiaceae | Herb | Tropical America | Annual | Sept-Mar |
| 16 | Indigofera linnifolia (L.f.) Retz. | Paplionaceae | Herb | Tropical Africa | Perennial | May-Oct |
| 17 | Ipomoea carnea Jacq. | Convolvulaceae | Shrub | Tropical America | Perennial | Jan-Dec |
| 18 | Ipomoea quamoclit L. | Convolvulaceae | Climber | Tropical America | Annual | Jun-Oct |
| 19 | Lantana camara L. | Verbenaceae | Herb | Tropical America | Perennial | Jan-Dec |
| 20 | Leonotis nepetifolia (L.) R. Br. | Lamiaceae | Herb | Tropical America | Annual | Sept-Nov |
| 21 | Leucaena leucocephala (Lam.) de Wit | Mimosaceae | Tree | Tropical America | Perennial | Apr-Jul |
| 22 | Malvastrum coromandelianum (L.) Garcke | Malvaceae | Herb | Tropical America | Annual | Oct-Apr |
| 23 | Martynia annua L. | Pedaliaceae | Herb | Tropical America | Annual | Jul-Oct |
| 24 | Oxalis corniculata L. | Oxalidaceae | Herb | Europe | Perennial | Feb-Oct |
| 25 | Parthenium hysterophorus L. | Asteraceae | Herb | Tropical north America | Annual | Oct-Mar |
| 26 | Peristrophe bicalyculata (Retz.) Nees | Acanthaceae | Herb | Tropical Africa | Perennial | Sept-Jan |
| 27 | Sida acuta Burm f. | Malvaceae | Herb | Tropical America | Perennial | Sept-May |
| 28 | Sonchus oleraceous L. | Asteraceae | Herb | Mediterranean | Annual | Mar-Nov |
| 29 | Tridax procumbens L. | Asteraceae | Herb | Tropical central America | Annual | Jan-Dec |
| 30 | Urena lobata L. | Malvaceae | Shrub | Tropical America | Perennial | Feb-Oct |
| 31 | Xanthium strumarium L. | Asteraceae | Herb | Tropical America | Annual | Aug-Sept |

Figure 3.
Variation of invasive alien plant species along an altitudinal gradient in the forests of Morni Hills, Panchkula.

Figure 4.
Species–family relationship of Invasive alien flora encountered during the study.

Figure 5.
Dendrogram showing the hierarchical clustering of flowering phenology of invasive alien plant species documented on the present study site.
Table 2.
Phytosociology of invasive plant species encountered from 400–600m AMSL (Range 1).
| S.N. | NAME | F | D | BA | IVI | H’ | Cd |
|---|---|---|---|---|---|---|---|
| 1 | Ageratum conyzoides L. | 33.3 | 32.32 | 0.00394 | 10.1166 | 0.15448 | 0.00115 |
| 2 | Argemone mexicana L. | 8.3 | 4 | 0.00046 | 2.07456 | 0.04168 | 0.00004 |
| 3 | Calotropis procera (Ait.) R.Br. | 16.6 | 12.32 | 0.04708 | 5.81129 | 0.10980 | 0.00045 |
| 4 | Celosia argentea L. | 8.3 | 2.64 | 0.00022 | 1.92299 | 0.03721 | 0.00004 |
| 5 | Croton bonpandlianum Baill. | 16.6 | 68.32 | 0.00355 | 10.6636 | 0.20085 | 0.00127 |
| 6 | Echinocloa colona (L.) Link. | 25 | 12.32 | 0.00019 | 6.24665 | 0.09767 | 0.00043 |
| 7 | Euphorbia heterophylla L. | 16.6 | 8.32 | 0.00113 | 4.18879 | 0.07271 | 0.00019 |
| 8 | Indigofera linnifolia (L.f.) Retz. | 16.6 | 39.32 | 0.00053 | 7.48600 | 0.14396 | 0.00062 |
| 9 | Ipomoea carnea Jacq. | 16.6 | 13 | 0.01592 | 5.07357 | 0.09351 | 0.00031 |
| 10 | Lantana camara L. | 83.3 | 102.64 | 2.51676 | 92.8332 | 0.66177 | 0.16358 |
| 11 | Lucaenea leucocephala (Lam.) de Wit | 33.3 | 3.32 | 0.53093 | 20.7231 | 0.31077 | 0.00796 |
| 12 | Martynia annua L. | 16.6 | 23.64 | 0.00513 | 5.92999 | 0.11234 | 0.00040 |
| 13 | Oxalis corniculata L. | 25 | 51.32 | 0.00046 | 10.4214 | 0.17827 | 0.00121 |
| 14 | Parthenium hysterophorus L. | 91.6 | 366.32 | 0.69915 | 75.3754 | 0.61101 | 0.07856 |
| 15 | Peristrophe bicalyculata (Retz.) Nees | 25 | 34 | 0.00392 | 8.66049 | 0.14647 | 0.00084 |
| 16 | Cassia occidentalis L. | 25 | 9 | 0.00415 | 5.99485 | 0.09214 | 0.00040 |
| 17 | Sida acuta L. | 16.6 | 105 | 0.00162 | 14.5332 | 0.26031 | 0.00236 |
| 18 | Urena lobata L. | 8.3 | 2.32 | 0.00044 | 1.89451 | 0.03636 | 0.00004 |
| 19 | Xanthium strumarium L. | 25 | 45.64 | 0.0095 | 10.0495 | 0.17178 | 0.00115 |
| Total | 507.6 | 935.76 | 3.84508 | 300 | 3.53318 | 0.26108 |
Table 3.
Phytosociology of invasive plant species encountered from 600–800m AMSL (Range 2).
| S.N. | NAME | F | D | BA | IVI | H’ | Cd |
|---|---|---|---|---|---|---|---|
| 1 | Ageratum conyzoides L. | 66.6 | 84.32 | 0.0103 | 17.4961 | 0.24433 | 0.00344 |
| 2 | Ageratum houstonianum Mill. | 58.3 | 76.32 | 0.00691 | 15.5278 | 0.22705 | 0.00270 |
| 3 | Alternanthera pungens Kunth | 16.6 | 5.32 | 0.00006 | 2.80783 | 0.05174 | 0.00008 |
| 4 | Bidena pilosa L. | 41.6 | 49 | 0.00533 | 10.5581 | 0.17147 | 0.00125 |
| 5 | Celosia argentea L. | 8.3 | 5.32 | 0.00028 | 1.66458 | 0.03779 | 0.00003 |
| 6 | Croton bonpandlianum Baill. | 16.6 | 10.64 | 0.00029 | 3.32528 | 0.06539 | 0.00012 |
| 7 | Euphorbia heterophylla L. | 16.6 | 12 | 0.00099 | 3.46679 | 0.06900 | 0.00013 |
| 8 | Ipomoea carnea Jacq. | 16.6 | 9.32 | 0.01143 | 3.35802 | 0.06623 | 0.00013 |
| 9 | Ipomoea quamoclit L. | 16.6 | 1.32 | 0.00008 | 2.42154 | 0.04096 | 0.00006 |
| 10 | Indigofera linnifolia (L.f.) Retz. | 25 | 5.64 | 0.00006 | 3.99897 | 0.06541 | 0.00017 |
| 11 | Leucaena leucocephala (Lam.) de Wit | 25 | 3.32 | 1.6503 | 27.5216 | 0.41079 | 0.01570 |
| 12 | Lantana camara L. | 100 | 189.64 | 4.8336 | 101.695 | 0.68362 | 0.19388 |
| 13 | Leonotis nepetifolia (L.) R. Br. | 50 | 23 | 0.3643 | 14.3711 | 0.22116 | 0.00314 |
| 14 | Malvastrum coromandelianum (L.) Garcke | 41.6 | 60 | 0.00261 | 11.5820 | 0.18894 | 0.0015 |
| 15 | Oxalis corniculata L. | 41.6 | 112.64 | 0.00084 | 16.6439 | 0.26548 | 0.00309 |
| 16 | Parthenium hysterophorus L. | 91.6 | 312 | 0.05954 | 43.6618 | 0.47971 | 0.02166 |
| 17 | Peristrophe bicalyculata | 16.6 | 6.64 | 0.00011 | 2.93612 | 0.05520 | 0.00009 |
| 18 | Sida acuta L. | 25 | 53 | 0.00075 | 8.58599 | 0.16250 | 0.00082 |
| 19 | Cassia occidentalis L. | 16.6 | 5.32 | 0.00076 | 2.81790 | 0.05201 | 0.00008 |
| 20 | Urena lobata L. | 16.6 | 7.64 | 0.00038 | 3.03665 | 0.05788 | 0.00010 |
| 21 | Xanthium strumarium L. | 16.6 | 2.32 | 0.00036 | 2.52221 | 0.04383 | 0.00007 |
| Total | 724 | 1034.72 | 6.94928 | 300 | 3.66058 | 0.24832 |
Table 4.
Phytosociology of invasive plant species encountered from 800–1000m AMSL (Range 3).
| S.N. | NAME | F | D | BA | IVI | H’ | Cd |
|---|---|---|---|---|---|---|---|
| 1 | Ageratum conyzoides L. | 16 | 13 | 0.00078 | 6.09844 | 0.10686 | 0.00041 |
| 2 | Ageratum houstonianum Mill. | 16 | 51.64 | 0.00145 | 12.3487 | 0.22044 | 0.00171 |
| 3 | Bidena pilosa L. | 16 | 10.64 | 0.00072 | 5.71551 | 0.09853 | 0.00036 |
| 4 | Boehmeria macrophylla (Thunb.) Hornem. | 16 | 2.32 | 0.21657 | 15.2191 | 0.26305 | 0.00442 |
| 5 | Chromolaena odorata (L.) R.M. King & H. Rob. | 16 | 89.32 | 0.00678 | 18.6790 | 0.30901 | 0.00396 |
| 6 | Cirsium arvense (L.) Scop. | 25 | 15 | 0.00093 | 8.65901 | 0.13139 | 0.00084 |
| 7 | Ipomoea carnea Jacq. | 16 | 16 | 0.04195 | 8.64880 | 0.15758 | 0.00103 |
| 8 | Lantana camara L. | 83 | 73.64 | 1.70715 | 118.181 | 0.67004 | 0.26830 |
| 9 | Malvastrum coromandelianum (L.) Garcke | 33 | 20.32 | 0.00103 | 11.5036 | 0.16115 | 0.00148 |
| 10 | Oxalis corniculata L. | 75 | 240.32 | 0.00528 | 57.5282 | 0.53101 | 0.03706 |
| 11 | Parthenium hysterophorus L. | 83 | 82.32 | 0.00806 | 34.2300 | 0.34643 | 0.01321 |
| 12 | Sonchus oleraceous L. | 8.3 | 7 | 0.00008 | 3.18831 | 0.06541 | 0.00011 |
| 13 | Urena lobata L. | 16 | 4.54 | 0.0006 | 4.57218 | 0.07431 | 0.00023 |
| Total | 419.3 | 626.06 | 1.9914 | 300 | 3.11860 | 0.32753 |
Table 5.
Phytosociology of invasive plant species encountered at >1000m AMSL (Range 4).
| S.N. | NAME | F | D | BA | IVI | H’ | Cd |
|---|---|---|---|---|---|---|---|
| 1 | Ageratum conyzoides L. | 41 | 11.64 | 0.00107 | 10.33411 | 0.15129 | 0.001193 |
| 2 | Ageratum houstonianum Mill. | 50 | 22.32 | 0.00066 | 14.76674 | 0.20840 | 0.002433 |
| 3 | Bidena pilosa L. | 50 | 34 | 0.00335 | 17.95162 | 0.25468 | 0.003606 |
| 4 | Cardamine hirsuta L. | 16 | 7.64 | 0.00018 | 4.858068 | 0.09495 | 0.000263 |
| 5 | Chromolaena odorata (L.) R.M. King & H. Rob. | 50 | 84.32 | 0.01354 | 31.64427 | 0.40873 | 0.01126 |
| 6 | Cirsium arvense (L.) Scop. | 25 | 5.32 | 0.00081 | 5.828146 | 0.09551 | 0.00038 |
| 7 | Lantana camara L. | 91 | 86.64 | 4.87483 | 138.601 | 0.67241 | 0.367264 |
| 8 | Malvastrum coromandelianum (L.) Garcke | 58 | 23 | 0.00079 | 16.35513 | 0.21853 | 0.002985 |
| 9 | Oxalis corniculata L. | 66 | 22 | 0.00262 | 17.52797 | 0.22224 | 0.003435 |
| 10 | Parthenium hysterophorus L. | 66 | 49.64 | 0.00409 | 24.96496 | 0.31784 | 0.00697 |
| 11 | Sonchus oleraceous L. | 41 | 23.32 | 0.00062 | 13.45496 | 0.20403 | 0.00202 |
| 12 | Urena lobata L. | 16 | 3.32 | 0.0008 | 3.713032 | 0.06762 | 0.000154 |
| Total | 570 | 373.16 | 4.90336 | 300 | 2.91626 | 0.401966 |

Figure 6.
Heatmap showing the Pearson Correlation of the various ecological parameters taken under study.