Floristic Inventory of Invasive Alien Aquatic Plants Found in Some Congolese Rivers, Kinshasa, Democratic Republic of the Congo

Abstract

Aim: To identify invasive aquatic alien plant species found in the Pool Malebo and some rivers in Kinshasa city, their behavior as well as their socio-economic impacts.
 Study Design: The study used a combination of purposive sampling and simple random sampling in order to select different sites where samples were collected.
 Place and Duration of Study: This study was carried out in different rivers (Pool Malebo system (Kinkole, Kingabwa), and N'sele, Funa and Lukaya rivers) of Kinshasa city in Democratic Republic of the Congo. The Pool Malebo is located along the Congo River. This was conducted between March and October 2013.
 Methodology: The collection was performed after a direct observation. The location of collection depended on sites, at Kingabwa and Kinkole, we collected invasive species in the middle of the Congo river and to achieve that, we used canoe. While at N’sele, Lukaya and Funa rivers, samples were collected at the edges. The collection took place in the morning between 7 and 11 am. Recorded species were classified either alien species or invasive alien species according to the status in the study region. The identification of collected species was carried out according to APG III. Seeing the way these species invade the environment and how they disturb the ecology of rivers, the physico-chemical characteristics of waters were measured between 7:00 and 11:00 am with the appropriate electronic probe for each parameter. For each parameter, the comparison between the sites was carried out using the ANOVA test with XLSTAT 2013 software.
 Results: Out of 151 specimens collected, 35 species have been identified of which 19 species as alien were identified and 4 proved to be invasive alien species, namely: Eichhornia crassipes, Echinochloa pyramidalis, Ludwigia peploides and Pistia stratiotes. These invasive species are used by farmers as livestock feed and also as green manure for different agricultural and farming activities, As to the physico-chemical characteristics, no significant differences were observed for the temperature and the turbidity in various sites while the pH and conductivity, there was a highly significant difference between different sites. The hydrology of these rivers is seriously disturbed due to the presence of these invasive alien species. These species constitute a serious threat in the erosion of aquatic biodiversity in the removal of native species in the formation of floating monospecific dense mats as observed.
 Conclusion: The invasion of alien species is a consequence of human activities and a concern, which affects all sectors of the society. It constitutes a true challenge for ecologists, economists, social scientists, agricultural engineers, environmentalists and other in order to develop and implement strong risk analysis frameworks and environmental impact assessments.

Ecological Characterization of Invasive Alien Species and Associated Abiotic Factors of Three Islands in the Pool Malebo in Kinshasa, Democratic Republic of the Congo

“…The identification of different species in the field was performed using specific identification keys (precisely Phylogenetic classification APG III) [18], while specimens which the identification was difficult in the field were brought to the herbarium of INERA, located at the department of Biology, Faculty of Sciences, University of Kinshasa. The study of the phytogeographical distribution is inspired from the chorological divisions recognized for tropical Africa as described in the literature [3].…”

“…There is an alternation of two seasons: A dry season from June to September and a rainy season from September to May [3,17].…”

“…In recent decades, invasive animal and plant species have become a major problem because of their environmental, economic and health effects. In the past few years, several studies [1][2][3] have tried to analyze relative contributions of several mechanisms to the success of the invasion. It is confirmed that this reductionist approach does not allow the understanding of this phenomenon [4].…”

“…Furthermore, species invasions are likely to increase on a par with climate change along with the international trade. With the climate change issue, these invasive species would inevitably provoke changes in biodiversity and in the ecosystem services that it provides [3,15].…”

“…In fact, most cases of invasiveness can be linked to the intended or unintended consequences of economic activities and therefore economic applications are essential to understand the problem and provide more accurate and comprehensive assessments of the benefits and costs of control alternatives to increase the effectiveness and efficiency of public funding [3]. However, invasive species are increasingly recognized as having important impacts on landscapes, ecosystems and levels of biodiversity [16].…”