Original Research Article

1 Original Research Article 2 3 Floristic Inventory and distribution of invasive alien aquatic plants 4 in Kinshasa (Pool Malebo, Kinkole, Kingabwa and the N’sele, FUNA 5 and Lukaya rivers) 6 7 8 Abstract 9 10 To make the botanical inventory of invasive alien plants and their distribution in the Kinshasa 11 hydrographic network, to evaluate their impacts in the environment, to know their socio-economic 12 importance and to propose sustainable and effective management measures. Surveys on the use of 13 aquatic exotic invasive plants have been conducted among rural populations in Kinshasa. The 14 identification of the plants was performed by our team in collaboration with the herbarium of the 15 University of Kinshasa to be identified by comparison through the INERA services competition, The 16 physical and physicochemical parameters of water were measured between 8:00 and 11:00 am. The 17 measurements were carried out with the appropriate electronic probe for each parameter. For each 18 parameter, the comparison between the sites was carried out using the ANOVA test, using the 19 XLSTAT 2013 software, and the graphics were obtained using the Origin Lab version 6.1 software. 20 Nineteen alien species were identified and four proved to be the most invasive: Eichhornia crassipes, 21 Echinochloa pyramidalis, Ludwigia peploides, Pistia stratiotes. Three species are multi-purpose, the 22 observation of hydrological parameters has shown that there are no significant differences for the 23 temperature in the different sites, for the PH the analysis indicates that the sites are differentiated in a 24 highly significant way, the analysis does not indicate a significant difference between the sites for 25 turbidity, as for the conductivity, indicates that the sites differ in a very highly significant way. 26 the floral inventory of exotic aquatic plants reveals nineteen species and four of which are invasive in 27 the environment, the socio-economic importance of the species are established around two categories 28 of use: livestock feed, green manure, these species pose a serious threat in the erosion of aquatic 29 biodiversity in the removal of native or local species in the formation of floating monospecific dense 30 mats. 31 32 Keywords: Exotic plants, invasive, uses, importance, Kinshasa, Democratic Republic of the Congo 33 34 35 1. INTRODUCTION 36 37 Species and ecosystems constitute the earth's biological diversity, and are so important that their loss 38 and degradation are disabling the nature. Species other than the human species have a right to 39 existence and a place in the world. We are unable to determine which species are essential or 40 redundant to the functioning of a given ecosystem and which ones will flourish in a changing world 41 (Convention on Biological Diversity, 2004). When a new species is being placed in an ecosystem, 42 often the impact is not immediately apparent, it will take a long enough period of time between 5 and 43 10 years in order to realize its environmental impacts (Convention on Biological Diversity, 2004). An 44 exotic species is a plant, an animal, a fish or a micro-organism that has been introduced as a result of 45 human activity, outside of its natural range. They are sometimes called alien species or non-native 46 species (Convention on Biological Diversity, 2004). An invasive alien species is an allochthonous 47 species of which the introduction or spread threatens the environment, the economy or the society, 48 including human health. It generally comes from another continent or region. 49 50 The different pathways through which invasive alien species can be introduced or spread are 51 intentional (deliberate), unintentional (accidental) introductions, and authorized or unauthorized 52 introductions. Among the different pathways are rivers, navigation, aquarium, pet trade, horticultural 53 seed trade, illegal entry of species with goods and by various modes of transport (Convention on 54 Biological Diversity, 2007). The history is rich in information and examples of disasters caused by 55 intentional introductions, such as the Nile perch, which resulted in the extinction of more than two 56 hundred fish species. Lessons from the past can help us avoid repeating such mistakes. 57 Unfortunately, these harmful practices continue such as the continuous implantation of the gambusie, 58 the international trade of the seeds of ornamental plants and pets (Convention on Biological Diversity, 59 2007). 60 61 In this work, the main focus was on the identification and behavior of invasive alien aquatic plants. 62 This study is a contribution to the 10-year Strategic Plan for Biodiversity 2011-2020 to the Aichi 63 Targets (Convention on Biological Diversity, 2010). This prompted us to study invasive alien aquatic 64 plants in the Pool Malebo system, which includes exotic plants such as water hyacinth (Eichhornia 65 crassipes Mart, Solms). Originally from South America, Eichhornia crassipes (Mart. Solms), a 66 pantropical hydrophyte belonging to the Pontederiaceae family, is one of the world's weeds. The 67 beautiful purple and purple flowers make it an ornamental plant very popular for ponds. Today, it is 68 present in more than 50 countries on the five continents. The water hyacinth grows very quickly, with 69 populations known to have doubled in less than 12 days (Convention on Biological Diversity, 2010). 70 Infestations of watercourses by this weed block access routes and navigation of water thus limiting the 71 maritime traffic, swimming and fishing. Water hyacinth also prevents light and oxygen from entering 72 the water and reaching submerged plants. Its shade encumbers native aquatic plants and severely 73 reduces the biological diversity of aquatic ecosystems. Currently it is ranked among the 100 most 74 invasive alien species in the world. 75 76 Its accidental invasion in the reaches of the Congo River dates back to the years 1954 and led the 77 Belgian colonial administration to promulgate on May 4, 1955 an order prohibiting the possession, 78 cultivation, multiplication, sale and transport of this plant considered, since, as invasive (Kikufi, 2006). 79 Sixty years later, in this current study, we are interested in the botanical inventory and distribution of 80 invasive aquatic exotic plants and others in the Malebo Pool and some rivers in the city of Kinshasa, 81 as well as their spread and distribution and their behavior and socio-economic roles. So, the choice 82 was made on the Malebo Pool system (Kinkole, Kingabwa), and the following rivers namely N'sele, 83 Funa and Lukaya. 84 85 2. MATERIAL AND METHODS 86 2.1 Study area 87 The study was conducted in the city of Kinshasa. We investigated on the floristic inventory and the 88 distribution of invasive alien aquatic plants in the Malebo pool system namely Kinkole, Kingabwa, and 89 to N'sele, Funa and Lukaya rivers (Figure 1). Data from this study were collected during the period 90 from March to October 2013. 91 92 93 94 95 96 Carte 2 : Relief et Hydrographie de Kinshasa ngo 97 Co du p. 98 Re 99 100 B 101 a so 102 ko 103 Y le o B e l inz k o 104 a a 105 M 106 u g i n d a M u h 107 L a b a s n u g u n T a k L u e u t i F l 108 n e i t j g a d T ' a s M N h 109 en k 110 e u 111 b m u 112 B 113 114 Plaine Echelle : 1/ 100.000 Cours d'eau N Marais et zones inondables Limite du Pays W E Fleuve Congo Source : Laboratoire de SIG / Sciences de la Terre (2007) S 115 116 117 Figure 1. Hydrography of Kinshasa city 118 2.2 Physical characteristics 119 Kinshasa City is located on the left bank of the Congo River where the watercourse draws a wide 120 crescent-circular pool: the Malebo Pool. The city lies between 4°17′30′′ and 4°30′00′′ latitude south and 121 15°12′ and 15°30′ longitude east. It is bound north and west by the Congo River, which is also the 122 border with the Popular Republic of Congo (Brazzaville), east and northeast by the Bandundu 123 Province, and south by the Bas Congo Province (Lateef et al. 2010). The city of Kinshasa in a low- 124 altitude climate is characterized by a hot and humid tropical climate of AW4 type according to Köppen's 125 classification (Lateef et al. 2010). There is an alternation of two seasons: a dry season from June to 126 September and a rainy season from September to the end of May. 127 128 2.3 Methods used 129 The identification of the plants in the field was performed by our own team of botanists, those species Comment [AL1]: How certain can the 130 of which the identification was hardly possible on the field because the samples were either botanically identification by bbotanist be ? 131 sterile (lack of flower and fruit) or absent from identification keys in our possession- were brought back Comment [AL2]: For what purpose were the 132 to the herbarium of INERA of Department of Biology, University of Kinshasa. plant species taken back to the herbarium ? kindly 133 state 134 2.4 Chorological study 135 The study of phytogeographic distribution is inspired by the chorological divisions recognized for 136 tropical Africa by the following authors: Lebrun, (1947, 1960 and 1966), Mullenders, (1954); Evrard, 137 (1968); Aubreville, (1962); Whyte, (1979) and Denys, (1980). 138 139 2.5 Hydrological parameters 140 They constitute elements of which manifestation conditions and influences, to varying degrees the 141 wetland macrophytes. From an ecological point of view, the analyzed parameters were the 142 temperature (°C), the pH, the turbidity or TDS, and the electrical conductivity which has been 143 measured (at 25 ° C) in micro-Siemens by cm (μS / cm).

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