Invasive Alien Flora in and around an Urban Area of India

Abstract

Invasive alien species are non-native exotic organisms which can disperse and destroy the biodiversity and change the ecosystem. The present study deals with the comprehensive list of invasive alien plants (IAPs) of Rourkela Steel City, Sundargarh, Odisha, with background information on family, habit, and nativity. A total of 165 invasive alien species under 132 genera and 59 families have been recorded. From the nativity study, among 25 geographic regions, the majority of invasive plants reported from American continent (62%) with 103 species. While in life form analysis, the herbs (114 species) are dominant, followed by trees (23 species), shrubs (22 species), climber (5 species), and undershrub (1 species). Ageratum conyzoides, Blumea lacera, Cassia alata, Lantana camara, Cassia tora, Parthenium hysterophorus, Xanthium sp., Datura sp., Cardamine scutata, Argemone mexicana, Grangea maderaspatana, Hyptis suaveolens, and Gnaphalium polycaulon are some noxious species found during the study. Parthenium hysterophorus is the highly noxious plant which is grown everywhere after Ageratum conyzoides and Lantana camara. Most of the invasive species are locally used for medicinal purposes as well as for food, fuel, and fodder purposes. A better planning and reporting of the spread of new plants in the area are needed for early identification and control of the invasive alien plant species in different seasons. Since the flora of Sundargarh districts has not been beneficially explored, this study will help in the compilation of flora of Sundargarh district and Rourkela in particular. Further studies will reveal the allelopathic effects on different agricultural crops as well as the different ethnobotanical values.

1. Introduction

Human beings depend on plants for his daily needs for which several numbers of plants are used to fulfill their purposes. Sometimes to fulfill human needs, plants are introduced intentionally by humans or accidentally from one region to another new region which is nonnative. These introduced plant species are called alien species or exotic species. The alien species invade the new region after well adapted to the environment. The plants which are introduced by human intentionally or accidentally by migration from its natural habitat to another new habit and their localities are known as alien, introduced, and exotic, originated from foreign or nonnative species [25, 33]. They have the potential to grow in any environmental conditions and are easily invasive to the new environment. Preston and Williams [22] stated that “Invasive alien plant species (IAPs)” are grown in such a way that they become as more dangerous to sustainable development. As a result, we are facing the great challenge of biodiversity loss all over the globe. These group of plant species act as the main cause for threat to the native biological diversity. They show various effects on the environment and economy of nonnative ecosystems. The exotic or alien plant species not only show negative impacts, but also they have much economic benefits. Now invasion alien species are cultivated to provide food, medicine, fuel, or fodder to local communities [9, 29]. The international trade of the products is helpful for introduction of these invasive alien species. Globally the introduction of IAPs leads to the huge loss of biodiversity and agriculture crops and health problems like respiratory illness [19].

Invasion of plants creates serious problems to the ecosystems by changing the structure, composition, and function of natural ecosystem [15, 17]. The rapid reproduction and growth rate, high dispersal ability, physiological adaptations to new conditions, and ability to survive on various ecosystems are the common characteristics of invasive plants. The IAPs have the ability to associate with human beings very easily. When the invasive plants colonized to grow in new areas, it can change the soil structure and composition of that area. It is reported that the agricultural lands are more threatened by IAPs because they are introduced by the crop seeds, garden plants, and wind breakers [24].

The first and most important step for effective and proper management of IAPs is to collect the baseline data about their invasion status, growth form, and life cycle. Accurately distinguishing between native and alien species is required not only when developing conservation and vegetation management plans but also for improving our understanding of the different components of biodiversity [21]. Rourkela, one of the major steel industrial centers of India and regarded as the industrial capital of Odisha, is situated in the north-eastern part of the state. Rourkela is located in Sundargarh district about 245 km from the shoreline of Bay of Bengal. It is located at 20° 12′ North latitude and 84° 53′ longitude, at the elevation about 219 m above the mean sea level. Due to better communication, abundance of natural mineral resources such as iron ore, limestone, dolomite, water, and other infrastructures in and around Rourkela is the main reason for the starting of industrialization since 1956. Studies on flora of Sundargarh district have not been fully explored. A few reports on flora of Sundargarh district [1, 2, 11, 13, 14] have been published. The study of literatures reveals that survey pertaining to major invasive plant species has not been reported earlier. It is high time to undertake complete survey of the flora of Sundargarh district with special emphasis on IAPs which may not be available in the future due to rapid industrialization. Many species may become endangered in the process of development, and they should be recorded and identified along with their usefulness before their extinction during rapid industrialization. Keeping in view, an attempt has been made in the present study to provide the baseline information on the invasive plant species in and around of Rourkela City of Sundargarh district. It will be helpful in preparation of district flora of Sundargarh.

2. Materials and method

During January 2012 to April 2019, intensive floristic surveys were undertaken in different areas of Rourkela Steel City (Figure 1) in such a way that each location could be studied in every season of the year. A comprehensive list of invasive alien plant species (IAPs) and the interaction with local inhabitants were made to collect the information regarding the various uses of IAPs of the area. Periodic collection of IAPs was made from each locality followed by identification using the available floras [6, 30]. The nativity, history, diversity, sources, and mode of introduction of these alien invasive plants were noted from the available literatures. The native ranges of the species were recorded from published literatures [3, 4, 5, 10, 12, 15, 16, 18, 19, 20, 24, 25, 26, 27, 31, 32, 36, 37, 38]. Plants were categorized according to their life forms as herb, undershrub, shrub, climber, and tree as well as their habit-wise as annual, biennial, and perennial. The studied habitats were wasteland, cultivated field, riverbank, pond bank, home garden, forest, roadside, etc. The economic importance of the IAPs was collected from the local inhabitants and surveyed literatures.

Figure 1.

Location map of Rourkela Steel City of Sundargarh district, Odisha, India.

3. Results and discussion

A total of 165 taxa of invasive alien plant species belonging to 132 genera and 59 families have been recorded from the Rourkela Steel City of Odisha (Table 1). The number of dicotyledonous IAPs found is 149 under 118 genera and 50 families, while 15 species of monocotyledons are found under 14 genera and 8 families. From the study, it was found that 114 species (69%) were herbs followed by trees with 23 species (14%), shrub 22 species (13%), climbers 5 species (3%), and undershrubs 1 species (1%) (Figure 2). The life form pattern distribution showed that herbaceous species (114 spp.) were dominant than other life forms (Table 2). The herbs can easily grow in any condition of environment and dominate to others. The habit distribution analysis showed that 56% (92 spp.) were annuals and 44% (73 spp.) were perennials. Table 3 showed the total number of IAPs recorded from the Rourkela Steel City and distributed under different families. From the taxonomic distribution of alien flora, Asteraceae (24 spp.) showed dominant impact among the invasive alien species in this region followed by Caesalpiniaceae (11 spp.), Convolvulaceae (9 spp.), Euphorbiaceae (8 spp.), Amaranthaceae (8 spp.), Poaceae (6 spp.), and Solanaceae (8 spp.), and Fabaceae, Malvaceae, and Verbenaceae represented only 5 spp. each (Table 4). These 10 dominant families contributed 89 species (54%) of the total invasive plant species studied (Figure 3). The genera Cassia and Ipomoea showed the highest number (six spp. each) followed by Cleome, Euphorbia, Alternanthera, Ludwigia, etc.

Sl no.	Plant species	Family	Life form	Habit	Nativity	Use
1	Abelmoschus esculentus Moench.	Malvaceae	Shrub	P	Trop. Africa	V, Ft
2	Acacia auriculiformis A. Cunn. ex Benth.	Mimosaceae	Tree	P	Australia	M, Ave, Sf
3	Acanthospermum hispidum DC.	Asteraceae	Herb	A	Brazil	M
4	Aerva lanata (L.) Juss. ex. Schult.	Amaranthaceae	Herb	P	Madagascar	M
5	Aeschynomene indica L.	Fabaceae	Herb	A	North America	Fu
6	Ageratum conyzoides L.	Asteraceae	Herb	A	Trop. America	Nox
7	Allium cepa L.	Liliaceae	Herb	A	Mediterranean	M, V
8	Aloe barbadensis Mill.	Liliaceae	Herb	P	Mediterranean	M
9	Alternanthera philoxeroides (Mart.) Griseb.	Amaranthaceae	Herb	P	Trop. America	V, M
10	Alternanthera pungens Kunth	Amaranthaceae	Herb	P	Trop. America	V
11	Alternanthera sessilis (Linn) DC.	Amaranthaceae	Herb	P	Trop. America	V, M
12	Amaranthus spinosus L.	Amaranthaceae	Herb	A	Trop. America	V
13	Antigonon leptopus Hook. & Arn.	Polygonaceae	Climber	P	Trop. S. America	O
14	Argemone mexicana L.	Papaveraceae	Herb	A	S. America (seventeenth cent.)	M, Nox
15	Bauhinia purpurea L.	Caesalpiniaceae	Tree	P	West Indies	V
16	Bidens pilosa L.	Asteraceae	Herb	A	Trop. America	M, Fo
17	Blainvillea acmella (L.) Philipson	Asteraceae	Herb	A	Trop. America (eighteenth)	M
18	Blumea lacera (Burm.f.) DC.	Asteraceae	Herb	A	Trop. America	Nox, M
19	Borassus flabellifer L.	Arecaceae	Tree	P	Trop. Africa	Ft, Fu
20	Bougainvillea spectabilis Willd.	Nyctaginaceae	Shrub	P	Brazil	O
21	Caesalpinia pulcherrima (L.) Sw.	Caesalpiniaceae	Shrub	P	Trop. America	O
22	Calotropis gigantea R. Br.	Asclepiadaceae	Shrub	P	Trop. Africa	M
23	Calotropis procera (Ait.) R. Br.	Asclepiadaceae	Shrub	P	Trop. Africa	M
24	Cannabis sativa L.	Cannabinaceae	Undershrub	P	Central Asia	M, Sm, Nar
25	Capsicum annuum L.	Solanaceae	Shrub	A	Trop. America	F
26	Cardamine scutata L.	Brassicaceae	Herb	A	Trop. America	NK, Nox
27	Cardiospermum halicacabum L.	Sapindaceae	Herb	A	Trop. America	M
28	Carica papaya L.	Caricaceae	Tree	P	Mexico	V
29	Cassia alata L.	Caesalpiniaceae	Shrub	P	West Indies	NK, Nox
30	Cassia fistula L.	Caesalpiniaceae	Tree	P	Pantropic	O, M, Sf
31	Cassia obtusifolia L.	Caesalpiniaceae	Herb	P	Trop. America	M
32	Cassia occidentalis L.	Caesalpiniaceae	Herb	P	S. America	M
33	Cassia siamea Lamk	Caesalpiniaceae	Tree	P	South East Trop. Asia	Fu, Ave
34	Cassia tora L.	Caesalpiniaceae	Herb	A	S. America (1824)	V, M, Nox
35	Casuarina equisetifolia Forster & Forster f.	Casuarinaceae	Tree	P	Australia	Fu, Sf
36	Catharanthus pusillus (Murr.) G. Don.	Apocynaceae	Herb	A	Trop. America	NK
37	Catharanthus roseus (Linn) G.Don	Apocynaceae	Shrub	P	West Indies	M
38	Celosia argentea L.	Amaranthaceae	Herb	A	Trop. Africa	V, M
39	Chenopodium album L.	Chenopodiaceae	Herb	A	Europe	V
40	Chloris barbata Sw.	Poaceae	Herb	P	Trop. America	Fo, Fu
41	Chromolaena odorata L.	Asteraceae	Herb	A	Trop. America	M
42	Chrozophora rottleri (Geisel.) Juss.	Euphorbiaceae	Herb	A	Trop. Africa	NK
43	Cleome gynandra L.	Capparaceae	Herb	A	Trop. America	M
44	Cleome monophylla L.	Capparaceae	Herb	A	Trop. Africa	V, M
45	Cleome rutidosperma DC	Capparaceae	Herb	A	Trop. America	NK
46	Cleome viscosa L.	Capparaceae	Herb	A	Trop. America	V, M
47	Convolvulus nervosus Burm.f.	Convolvulaceae	Herb	A	Europe	M
48	Corchorus aestuans L.	Tiliaceae	Herb	A	Trop. America	Fu
49	Crotalaria pallida Ait	Fabaceae	Herb	A	Trop. America	Fi, Fu
50	Crotalaria retusa L.	Fabaceae	Herb	A	Trop. America	Fi, Fu
51	Croton bonplandianum Baill.	Euphorbiaceae	Herb	P	S. America	M
52	Cucumis melo L.	Cucurbitaceae	Climber	A	Iran and N. West	V
53	Cuscuta reflexa Roxb.	Cuscutaceae	Herb	A	Mediterranean	M
54	Cynodon dactylon (L.) Pers.	Poaceae	Herb	P	Trop. America	M
55	Cyperus difformis L.	Cyperaceae	Herb	P	Trop. America	M
56	Cyperus iria L.	Cyperaceae	Herb	P	Trop. America	M
57	Datura innoxia Mill.	Solanaceae	Shrub	P	Trop. America	M, Nox
58	Datura metel L.	Solanaceae	Shrub	P	Trop. America	M, Nox
59	Delonix regia (Boj.) Raf.	Caesalpiniaceae	Tree	P	Madagascar	O, Ave, Sf
60	Duranta repens L.	Verbenaceae	Shrub	P	America	O
61	Echinochloa colona (L.) Link	Poaceae	Herb	A	Trop. S. America	Fo
62	Echinochloa crus-galli Beauv.	Poaceae	Herb	A	Trop. S. America	Fo
63	Eclipta prostrata L.	Asteraceae	Herb	A	Trop. America (Bf1824)	M
64	Eichhornia crassipes (Mart.) Solm.	Pontederiaceae	Herb	P	Trop. America	St
65	Emilia sonchifolia (L.) DC.	Asteraceae	Herb	A	Trop. America	V, M
66	Eucalyptus citriodora Hook.	Myrtaceae	Tree	P	Australia	M, Fu, Sf
67	Euphorbia heterophylla auct. Non L.	Euphorbiaceae	Herb	A	Trop. America	O
68	Euphorbia hirta L.	Euphorbiaceae	Herb	A	Trop. America	M
69	Euphorbia pulcherrima Willd. ex. Klotz	Euphorbiaceae	Shrub	P	Mexico	O
70	Euphorbia thymifolia L.	Euphorbiaceae	Herb	P	Trop. America	NK
71	Evolvulus nummularius L.	Convolvulaceae	Herb	P	Trop. America	M
72	Gnaphalium polycaulon Pers.	Asteraceae	Herb	A	Trop. America	NK, Nox
73	Gomphrena celosioides Mart.	Amaranthaceae	Herb	A	S. America	Fo
74	Gomphrena globosa L.	Amaranthaceae	Herb	A	America	O
75	Grangea maderaspatana L.	Asteraceae	Herb	A	Trop. S. America	NK, Nox
76	Grevillea robusta Cunn. ex R.Br.	Proteaceae	Tree	P	Australia	Fu, Sf
77	Helianthus annuus L.	Asteraceae	Herb	A	America	O, Oil
78	Heliotropium indicum L.	Boraginaceae	Herb	A	S. America	M
79	Hibiscus rosa-sinensis L.	Malvaceae	Shrub	P	China	M, O
80	Hyptis suaveolens (L.) Poit.	Lamiaceae	Herb	A	Trop. America	M, Nox
81	Impatiens balsamina L.	Balsaminaceae	Herb	A	Trop. America	O
82	Indigofera linnaei Ali	Fabaceae	Herb	A	Trop. Africa	M
83	Ipomoea batatas (L.) Lam.	Convolvulaceae	Climber	P	Trop. America	Ft
84	Ipomoea carnea Jacq.	Convolvulaceae	Shrub	P	Trop. America	Fu
85	Ipomoea hederifolia L.	Convolvulaceae	Herb	A	Trop. America	M
86	Ipomoea obscura (L.)Ker-Gaw	Convolvulaceae	Herb	P	Trop. Africa	NK
87	Ipomoea pes-tigridis L.	Convolvulaceae	Herb	A	Trop. East Africa	M
88	Ipomoea quamoclit L.	Convolvulaceae	Herb	P	Trop. America	M
89	Jatropha gossypifolia L.	Euphorbiaceae	Shrub	P	Brazil	M
90	Justicia gendarussa Burm.f.	Acanthaceae	Shrub	P	China	M
91	Kalanchoe pinnata (Lam.) Pers.	Crassulaceae	Herb	P	Trop. Africa	O, M
92	Kigelia pinnata DC	Bignoniaceae	Tree	P	Africa	O, Ave, Sf
93	Lagerstroemia indica L.	Lytharaceae	Shrub	P	China	O
94	Lantana camara L.	Verbenaceae	Shrub	P	Trop. America	M, Nox
95	Leonotis nepetifolia (L.) R.Br.	Lamiaceae	Herb	A	Trop. Africa	M
96	Leucaena leucocephala (Lam.) de Wit.	Mimosaceae	Tree	P	Trop. America	Fu, Sf
97	Ludwigia adscendens (L.) Hara	Onagraceae	Herb	A	Trop. America	Sb
98	Ludwigia octovalvis (Jacq.) Raven	Onagraceae	Herb	A	Trop. America	M, Sb
99	Ludwigia perennis L.	Onagraceae	Herb	A	Trop. America	M, Sb
100	Malvastrum coromandelianum (L.) Garcke	Malvaceae	Herb	A	Trop. America	M, Fi
101	Martynia annua L.	Martyniaceae	Herb	A	Trop. America	M
102	Mecardonia procumbens (Mill.) Small	Verbenaceae	Shrub	A	T. N. America	NK
103	Melochia corchorifolia L.	Sterculiaceae	Herb	A	Trop. America	NK
104	Merremia vitifolia (Burm.f.) Hall.f.	Convolvulaceae	Herb	A	Trop. America	NK
105	Mikania micrantha L.	Asteraceae	Herb	A	Trop. America	Nox
106	Mimosa pudica L.	Mimosaceae	Herb	P	Brazil	M
107	Mirabilis jalapa L.	Nyctaginaceae	Herb	P	Peru	O, M
108	Morus australis Poir.	Moraceae	Tree	P	China	Ft
109	Nicotiana tabacum L.	Solanaceae	Herb	A	S. America	Nar, Sm
110	Ocimum canum Sims	Lamiaceae	Herb	A	Trop. America	M
111	Opuntia stricta (Haw.) Haw.	Cactaceae	Shrub	P	Trop. America	NK
112	Oxalis corniculata L.	Oxalidaceae	Herb	A	Europe	M
113	Parthenium hysterophorus L.	Asteraceae	Herb	A	Trop. America	Nox
114	Passiflora foetida L.	Passifloraceae	Climber	P	Trop. S. America	O, M
115	Pedalium murex L.	Pedaliaceae	Herb	A	Trop. America	M
116	Peltophorum pterocarpum (DC.) Backer ex K.Heyne	Caesalpiniaceae	Tree	P	Malaya	Ave, Sf
117	Peperomia pellucida (L.) Kunth	Piperaceae	Herb	A	Trop. S. America	M
118	Peristrophe bicalyculata (Retz.) Nees.	Acanthaceae	Herb	A	Trop. America	NK
119	Phoenix sylvestris (L.) Roxb.	Arecaceae	Tree	P	Trop. America	Ft, Fu
120	Phyla nodiflora (L.) Greene	Verbenaceae	Herb	A	Trop. America	M
121	Physalis angulata L.	Solanaceae	Herb	A	Trop. America	M, Ft
122	Physalis minima L.	Solanaceae	Herb	A	Trop. America	M, Ft
123	Pistia stratiotes L.	Araceae	Herb	P	Trop. America	M, St
124	Pithecellobium dulce (Roxb.) Benth.	Mimosaceae	Tree	P	Mexico	Ft
125	Plumeria rubra L.	Apocynaceae	Tree	P	S. America	O
126	Portulaca oleracea L.	Portulacaceae	Herb	A	Trop. S. America	M, V
127	Portulaca quadrifida L.	Portulacaceae	Herb	A	Trop. America	M, V
128	Quisqualis indica L.	Combretaceae	Climber	P	Malaya	O
129	Rhoeo discolor Hance.	Commelinaceae	Herb	P	Central America	O
130	Richardia scabra L.	Rubiaceae	Herb	A	S. America	NK
131	Ricinus communis L.	Euphorbiaceae	Shrub	P	Africa	M
132	Ruellia tuberosa L.	Acanthaceae	Herb	A	Trop. America	NK
133	Saccharum spontaneum L.	Poaceae	Herb	A	T. West Asia	Th, Fu, Fo
134	Scoparia dulcis L.	Scrophulariaceae	Herb	A	Trop. America	M
135	Sida acuta Burm.f.	Malvaceae	Herb	A	Trop. America	M
136	Solanum nigrum L.	Solanaceae	Herb	A	Trop. America	M
137	Solanum torvum Sw.	Solanaceae	Shrub	P	West Indies	M
138	Sonchus asper (L.) Hill	Asteraceae	Herb	A	Mediterranean	M
139	Spathodea campanulata Beauv.	Bignoniaceae	Tree	P	Trop. Africa	Ave, Sf
140	Spermacoce articularis L.	Rubiaceae	Herb	A	Trop. America	NK
141	Sphaeranthus indicus L.	Asteraceae	Herb	A	Trop. Africa	M
142	Spilanthes acmella (L.) L.	Asteraceae	Herb	A	North America	M
143	Spinacia oleracea L.	Chenopodiaceae	Herb	A	Europe	V
144	Stachytarpheta jamaicensis (L.) Vahl.	Verbenaceae	Herb	A	Trop. America	M
145	Stylosanthes hamata L.	Fabaceae	Herb	A	Trop. Africa	Fo
146	Synedrella nodiflora (L.) Gaertn.	Asteraceae	Herb	A	West Indies	M
147	Tagetes erecta L.	Asteraceae	Herb	A	Mexico	O, M
148	Tagetes patula L.	Asteraceae	Herb	A	Mexico	O, M
149	Tamarindus indica L.	Caesalpiniaceae	Tree	P	Trop. America	Ft
150	Tecoma stans (L.) Juss. ex Kunth	Bignoniaceae	Tree	P	America	O
151	Thevetia peruviana (Pers.) Merrill	Apocynaceae	Tree	P	Trop. America	M
152	Thuja orientalis L.	Cupressaceae	Tree	P	China	O
153	Tribulus terrestris L.	Zygophyllaceae	Herb	A	Trop. America	M
154	Tridax procumbens L.	Asteraceae	Herb	P	Mexico	M
155	Triumfetta pentandra A.Rich.	Tiliaceae	Herb	A	Trop. America	M
156	Turnera ulmifolia L.	Turneraceae	Herb	P	Trop. America	O
157	Typha angustata Bory & Chaub.	Typhaceae	Herb	P	Trop. America	Th, Fu, Fo
158	Urena lobata L.	Malvaceae	Herb	A	Trop. Africa	Fib, Fu
159	Vernonia cinerea L.	Asteraceae	Herb	A	S. America	M
160	Waltheria indica L.	Sterculiaceae	Herb	A	Trop. America	M
161	Xanthium indicum L.	Asteraceae	Herb	A	Trop. America	M, Nox
162	Xanthium strumarium L.	Asteraceae	Herb	A	Trop. America	M, Fu, Nox
163	Zinnia elegans Jacq.	Asteraceae	Herb	A	Mexico	O
164	Zea mays L.	Poaceae	Herb	A	America	F, Fu, Fo
165	Ziziphus mauritiana Lam.	Rhamnaceae	Tree	P	China	Ft

Table 1.

List of invasive alien plant species (IAPs) recorded from Rourkela Steel City, Sundargarh, Odisha.

Note: F, food; FT, fruit; O, ornamental; not known; M, medicinal; Fu, fuel; Fib, fiber; V, vegetable; Sp, species; Nox, noxious; Sm, smoking; Co, compost; Sa, sacred plant; Sb, soil binder; Ch, chemical compounds; Ave, avenue; T, thatching; A, annual; P, perennial.

Figure 2.

Habit-wise distribution of invasive alien plant species in Rourkela.

Sl. no.	Habit	No. of species
1	Herb	114
2	Shrub	22
3	Tree	23
4	Climber	5
5	Undershrub	1

Table 2.

Habit of invasive alien plant species in Rourkela Steel City of Odisha.

Sl. no.	Nativity	No. of species
1	America	5
2	Central America	1
3	North America	2
4	South America	10
5	Tropical America	77
6	Tropical South America	7
7	Tropical North America	1
8	Africa	2
9	Tropical Africa	15
10	Tropical East Africa	1
11	Brazil	4
12	Australia	4
13	West Indies	5
14	Mexico	7
15	Malaya	2
16	Madagascar	2
17	Europe	4
18	China	6
19	Iran North West	1
20	Pantropic	1
21	Peru	1
22	South East Tropical Asia	1
23	Tropical West Asia	1
24	Central Asia	1
25	Mediterranean	4

Table 3.

Different geographic nativities of the invasive alien plants.

Sl. no.	Family	No. of species
1	Acanthaceae	3
2	Amaranthaceae	8
3	Apocynaceae	4
4	Araceae	1
5	Arecaceae	2
6	Asclepiadaceae	2
7	Asteraceae	24
8	Balsaminaceae	1
9	Bignoniaceae	3
10	Boraginaceae	1
11	Brassicaceae	1
12	Cactaceae	1
13	Caesalpiniaceae	11
14	Cannabinaceae	1
15	Capparaceae	4
16	Caricaceae	1
17	Casuarinaceae	1
18	Chenopodiaceae	2
19	Combretaceae	1
20	Commelinaceae	1
21	Convolvulaceae	9
22	Crassulaceae	1
23	Cucurbitaceae	1
24	Cupressaceae	1
25	Cuscutaceae	1
26	Cyperaceae	2
27	Euphorbiaceae	8
28	Fabaceae	5
29	Lamiaceae	3
30	Liliaceae	2
31	Lytharaceae	1
32	Malvaceae	5
33	Martyniaceae	1
34	Mimosaceae	4
35	Moraceae	1
36	Myrtaceae	1
37	Nyctaginaceae	2
38	Onagraceae	3
39	Oxalidaceae	1
40	Papaveraceae	1
41	Passifloraceae	1
42	Pedaliaceae	1
43	Piperaceae	1
44	Poaceae	6
45	Polygonaceae	1
46	Pontederiaceae	1
47	Portulacaceae	2
48	Proteaceae	1
49	Rhamnaceae	1
50	Rubiaceae	2
51	Sapindaceae	1
52	Scrophulariaceae	1
53	Solanaceae	8
54	Sterculiaceae	2
55	Tiliaceae	2
56	Turneraceae	1
57	Typhaceae	1
58	Verbenaceae	5
59	Zygophyllaceae	1

Table 4.

Total number of IAPs’ distributed family-wise species in Rourkela Steel City.

Figure 3.

Family-wise distribution of invasive alien plants in Rourkela Steel City of Odisha.

The contribution of different geographical regions or the nativity of invasive alien species is shown in Table 3. A total of 25 native geographical regions of IAPs were recorded. The major geographical regions or nativities of IAPs were Tropical America 77 species, Tropical South America 7 spp., Central America 1 spp., South America 10 spp., Tropical Africa 15 spp., Mexico 7 spp., and Europe 4 spp. IAPs are having negative impacts on the ecosystem and biodiversity of that region. Besides they are also found to be useful to local inhabitants. From the survey of literatures and interaction with local people about the IAPs, several plant species were used for different purposes like medicine, vegetables, fuels, fodders, etc. The study revealed that 87 spp. are used as medicine, while 18 spp. are used as fuel, 9 spp. used for fodders, and 30 spp. used for ornamental and avenue purposes. A total of 28 spp. were used as edible in the form of fruit, vegetables, oil, etc. Several species like Argemone mexicana, Euphorbia hirta, Mimosa pudica, Ocimum canum, Calotropis spp., Croton bonplandianus, Catharanthus roseus, etc. were mostly common medicinal plants used by local people, kabiraj and baidyas, while plants like Cassia siamea, Leucaena leucophloea, Kigelia pinnata, etc. were used for avenue plantation and social forestry. Cannabis sativa and Nicotiana tabacum were not only used for medicines, but also they are used for smoking as narcotic products. Alien species have been classified into naturalized and noxious species by various workers [8, 28, 39]. Many reports say different alien species become noxious after naturalized. Ageratum conyzoides, Blumea lacera, Cassia alata, Lantana camara, Cassia tora, Parthenium hysterophorus, Xanthium sp., Datura sp., Cardamine scutata, Argemone Mexicana, Grangea maderaspatana, Hyptis suaveolens, and Gnaphalium polycaulon were some noxious species found during the study. Parthenium hysterophorus was one of the highly noxious and abundantly grown plant species next to Ageratum conyzoides and Lantana camera.

From the taxonomical study, Asteraceae was the most dominant invasive family which dominated all other species due to its adaptive nature of seeds in different areas. The plant species have high reproductive potential to produce minute seeds so fast which disperse in new area through wind, air, and water. From the literature study, it was found that Asteraceae was more invasive in other areas of India [5, 7, 8, 23, 31, 32, 34, 35, 37] and also all over the world. Mallick et al. also found Asteraceae as the most dominating group of weeds among all other plant family groups. Mikania micrantha, a climber of Asteraceae, can climb trees and walls easily which inhibit the growth of the trees as well as cover the whole area so rapidly. Parthenium hysterophorus was another noxious plant of this family which could cause black fever disease. It grows very rapidly as its seeds disperse and grow so fast in new area which become invasive later. Annuals showed dominance over perennials among the invasive species as annuals complete life cycle and produce seeds to disperse in a short period in a year. Habit-wise distribution showed that herbaceous plants become more invasive than shrubs, climbers, and trees. Herbs have more tolerance to harsh condition and have great viability to grow in any condition which helps to become more invasive than others. Kumar et al. [11] found herbs as the more dominant plant group found in Rourkela flora.

4. Conclusion

The invasive species are nonnative and exotic which are introduced intentionally for different purposes and sometimes accidentally introduced to a new area. The invasive species are more adapted to new areas by rapidly growing and reproducing more biomass than the native plant biodiversity. As a result, they can change the native ecosystem and become threats to the native ecosystem. IAPs also change the quality of soil, nutrient capacity, as well as the biodiversity present inside the soil. After invasion some invasive plants become narrow and noxious which affects the ecosystem with extinction of species and also affects the human health. Public involvement can be used and needed for early detection and reporting of infestations of the spread of new weeds as invasive species in the area. People should aware about the invasive species and its allelopathic effects on the environment and human health. Invasive species are now becoming more serious causing sustainable use of biodiversity and their impacts on invaded environment. Invasive alien plant species diversity in Rourkela of Sundargarh, Odisha, is a threat for the present flora due to their aggressive growth, colonizing ability, and adaptability. After invasion, their population growth increases rapidly in the new ecosystem; as a result they encroach crop fields, wastelands, and barren lands. The increased rate of invasion by alien species directly affects the agricultural economy and the biodiversity. Hence, eradication of IAPs should be done urgently. So awareness among local people is one of the methods to control IAPs. Besides this, the utilization of hidden medicinal potential can make IAPs beneficial to the people of the region. Moreover, the effect of IAPs in the economy, biodiversity, and human health is yet to be assessed. This study is based on diversity of invasive plant species found in different areas of Rourkela. Since the flora of Sundargarh district has not been beneficially and fully explored, this study will help in the compilation of flora of Sundargarh district and Rourkela in particular. Further studies reveal the allelopathic effects of IAPs on different plants, agricultural crops, and their ethnobotanical values.

Acknowledgments

Authors acknowledge the people of Rourkela for their kind cooperation and for sharing valuable information during the study.