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Sericostachys scandens , liane envahissante, represente une menace pour la diversite biologique. La presente etude a pour objectif d’evaluer l’effet des trouees, de l’altitude et de la pente sur l’abondance de S. scandens dans le Parc National de la Kibira au Burundi; et l’influence de cette liane sur la composition floristique des herbacees. L’abondance de S. scandens et des plantes herbacees a ete mesuree dans 50 trouees et 50 parcelles temoins sous couverture forestiere et soumise a une regression binomiale negative et a une analyse multivariee de la variance sur matrice de dissimilarite. La superficie des trouees a un effet positif sur l’abondance de S. scandens (z = 4,99; p < 0,0001) alors que l’altitude a un effet negatif (z = -12,63; p < 0,0001). L’invasion des stations forestieres par S. scandens modifie la composition floristique en herbacees (p= 0,01). La strategie de surveillance du PNK devrait renforcer les patrouilles pour limiter la creation de trouees d’origine anthropique. Mots cles : Trouees, invasion, liane, diversite, Parc, Burundi. English Title: Expansion of the invasive liana Sericostachys scandens Gilg & Lopr. (Amaranthaceae) in moist mountain forests: ecological determinants and impacts on herbaceous plants Sericostachys scandens, an invasive liana, represents a threat to biological diversity. The present study aimed at evaluating of the effect of gaps, altitude and slope on the abundance of S. scandensin the Kibira National Park in Burundi; and the influence of this liana on the floristic composition of herbaceous plants. The abundance of S. scandens and herbaceous plants was measured in 50 gaps and 50 control plots under forest cover and subjected to negative binomial regression and multivariate variance analysis on dissimilarity matrix. The light gap area has a positive effect on the abundance of S. scandens (z = 4.99, p < 0.0001) while the altitude has a negative effect (z = -12.63, p < 0, 0001). The invasion of forest stations by S. scandens changes the floristic composition of herbaceous plants (F = 315.026, p = 0.01). The strategy of KNP surveillance should strengthen patrols to limit the creation of anthropogenic gaps. Keywords : Gaps, invasion, liana, diversity, Park, Burundi.

Centemopsis , Dasysphaera ¸ Neocentema , Nototrichium , Ptilotus , and Sericostachys are the generic names in Amaranthaceae which still appear untypified. Lectotypes of these names (according to the Art. 10.1 Note 1 of ICN) are designated in the present paper. On the basis of the Art. 10.1, I also investigated here the generitypes of the names, which are not typified [ Centema glomerata , Dasysphaera tomentosa , Nototrichium viride , Ptilotus corymbosus , and Sericostachys scandens ]. Specimens preserved at BM, GH, and S, and an image by Lopriore were chosen for the purpose of typification. Isolectotypes for the names Nototrichium viride , and Sericostachys scandens are also indicated from among specimens deposited at BISH, K, L, P, US, and WAG. The indications as holotype/isotype by Townsend and Bean (specimens preserved at BM, K, M, and Z) for the names Centema alternifolia , Dasysphaera tomentosa , and Ptilotus corymbosus were corrected (lectotype/isolectotype) according to the Art. 9.9, ex. 10. “ Ptilotus sandwicensis ”, which is currently considered as the basionym of “ Nototrichium sandwicense ”, is a nomen nudum and therefore not validly published according to the Art. 38.1 of ICN. As a consequence, the proposed combinations “ Nototrichium sandwicense ” by Hillebrand, and “ Psilotrichium sandwicense ” by Seeman were not validly published either.

This chapter focuses on the lianas from DR Congo where few recent studies have been conducted. It reports on two developments in liana dynamics in the Congo Basin. First, the chapter presents results from the liana dynamics plots of Ituri, in the eastern DR Congo. The Ituri plots, which are the largest of the Central/Eastern African liana communities and their dynamics, were first sampled in the early 1990s with the establishment of four 10-ha plots. Second, the chapter addresses the dynamics of the invading climber species Sericostachys scandens. Data is presented for lianas in the two 10-ha plots located in the mixed Edoro forest. The chapter also presents liana results for the inventory of 2007 and for changes since 1994. Liana densities in the few African forests that have been studied are similar to other continents, but species diversity appears to be higher.

Sericostachys scandens is a monocarpic and heliophilous liana, native in tropical African forests. In the montane forests of the Kahuzi-Biega National Park (KBNP) (East of DR Congo), it has been expanding very strongly for a decade, and is currently considered as having negative impacts on biodiversity conservation. In this paper, we test if S. scandens differs from three co-occurring, native, non spreading lianas (Gouania longispicata, Tacazzea apiculata and Adenia bequaertii) for functional traits which might influence plant expansion. For leaf traits (SLA, dry matter content, nitrogen concentration), S. scandens did not show extreme values compared to those of the three other lianas. In contrast, S. scandens had much higher biomass allocation to sexual reproduction. It also differs from the three other lianas for its reproductive strategy that combines both vegetative propagation and sexual reproduction, and propagule dispersal by wind. Moreover, S. scandens has larger leaves and a greater number of lateral branches per unit stem length. It is argued that the particular combination of functional traits exhibited by S. scandens may in part explain its propensity to behave as an opportunistic weed in the disturbed areas in the montane forests of Kahuzi-Biega. © 2012 Science Press, Institute of Mountain Hazards and Environment, CAS and Springer-Verlag Berlin Heidelberg., SCOPUS: ar.j, info:eu-repo/semantics/published