A novel alien invasive species introduction, Clerodendrum paniculatum Linn (Pagoda) Lamiaceae, in a tropical African forest


 We record a novel introduction of Clerodendrum paniculatum in Africa. The novel species appears to have a negligible impact within the new environment. In this communication, we describe the novel alien species and the environment to which it has been introduced.


Introduction
The introduction of novel alien species into new habitats was not a global issue until such habitats began to lose three integral parts of biodiversity, such as ecosystem, species, and genetic diversity, to novel alien species (CBD 2009). Consequently, biological invasion introduces novel alien species to native plant communities (Satterthwaite et al. 2007), forms species colonies (Augusto et al 2001, Luzuriaga et al 2005, and causes differential characteristics in genetic validation, all contributing to biodiversity losses (McNeely et al 2001, Mack et al 2000. The losses brought about by novel alien species invasion are undoubtedly a critical issue in the world economy, speci cally developing countries in Africa (Nuñez & Anıbal 2010). Due to provenance variation, little is still known of the effective mechanism to eradicate the level of novel alien species invasion (Engiberger 2009, Flory 2019) in developing countries. Therefore, biodiversity conservation of indigenous plant ecosystems requires obtaining an adequate sample of unperturbed ecosystem types of an endangered species in perpetuity, which becomes an example of the original forest that is used for the Strict Nature Reserve (Omomoh et  In the present study, an introduction of the alien plant species Clerodendrum paniculatum Linn, commonly known as Pagoda ower, and one of the 150 original species in the genus Clerodendrum was detected and collected for the rst time in an African forest. C. Paniculatum is abundant in tropical and subtropical Asia where it is commonly encountered and widely cultivated for its medicinal uses. There is no current information regarding the presence of C. paniculatum in Africa. Additionally, Iyama et al (2015) did not report any collections of this species either in forests, elds, or gardens, which places this plant among the lesser-known alien species in Nigeria (Adekunle 2009). The species is a well-known invader in several parts of the world (Englberger 2009), native to Europe and Australia, and is predominant in Asian countries like Bangladesh, Laos, China, Cambodia, Sri Lanka, Vietnam, Malaysia, Indonesia Taiwan (Prashithet al 2018, Leeratiwong 2011, Bhat 2014, Melapu 2015. The genus Clerodendrum (Linn.-F.T.A. 5: 292;B. Thomas in Engl. Bot. Jahrb. 68: 1.1936) was formerly placed in the family Verbenaceae but is now placed in the family Lamiaceae (Cantino et al., 1992 andHarley et al., 2004).
This genus is composed of c.a. 400 species of mostly shrubs or trees, erect or rarely climbing, deciduous or evergreen. They are found mostly in the tropics and sub-tropics across Asia, Europe, Africa, and the Americas (Shou-liang and Gilbert 1994). Thirty species have been recorded in Africa alone (FWTA 1963), 34 species across China (Shou-liang and Gilbert 1994). In Nigeria, 18 species are recorded according to Flora of West Tropical Africa, and 9 of these species are indigenous (Gbile et al 2002).

Sampling Design
In March 2020, we collected samples of Clerodendrum paniculatum at two sites; Forest plantation and Strict Nature Reserve at the forest reserve, Nigeria. Four temporary sample plots of 400m 2 (two at each site) were haphazardly selected along the vegetation road edge where C. paniculatum was found. The rst 10m line of 400m 2 (20m by 20m) was stationed to start from the rst C. paniculatum, where it was sighted at the spatial area from the road edge to the smaller spatial area of the site (adjacent to the road edge). The scienti c name and family followed the ora of West Tropical Africa (Hutchinson et al 1963).

Data analyses
The plant species were categorized into their life forms using Hutchinson et al (1963). The percentage of species relative density was calculated using: (1) Where RD = species relative density, ni = number of individuals of species i, N = total number of all plant species in the entire community.

Specimen
We rst discovered C. paniculatum while collecting specimens for herbarium collection (Omomoh et al 2019). We visually estimated C. paniculatum cover at each site. Specimens of owering parts and leaves were collected in September of 2014, brought to the herbarium, and examined while still fresh. Latitude and longitude for each site were taken using a Garmin GPS 60. After a thorough plant examination, collections were identi ed as Clerodendrum. For more speci c identi cation, we sent specimens to Aleksi Baznekian (Joseph Keefe Herbarium, USA), who identi ed the specimen as C. paniculatum L. Additionally, we cross-checked our specimen with the studies of Deori et al (2012) and Prashith & Sudharshan (2018).

Distribution in Nigeria: South West Ondo, Akure forest reserve
This Akure forest area is humid sub-tropical with a mean temperature of 26ºC (range of 19ºC -34ºC). The wet season is from March to November (2500 mm bimodal rainfall pattern) and the dry season from December to February (Omomoh 2018, Omomoh et al 2019, Omomoh et al 2020. The Akure forest reserve is a tropical successional rainforest situated between two communities, Aponmu and Obada in Owena. Local government encompasses the two study sites, Forest plantation, and Strict Nature Reserve, where the novel alien species was rst located and collected. The novel species is a tropical evergreen shrub that was found in dry and mixed deciduous forests along the major roadside in two different regions (Forest Plantation and marginal area of theStrict Nature Reserve; Figure 1). This part of the forest has been going through succession following human disturbance since the initiation of the forest reserve (Onyekwelu. et al 2008). The C. paniculatum species are more scanty and sturdy in the Strict Nature Reserve than in the Forest Plantation where the species was growing bigger and taller. The species height varied from one C. paniculatum to another (75cm to 1.3m) due to the degree of sunlight exposure received.
Shrubby tree (Figure 2, 3a and 3b) about 2 -3 m high; stem stout in a square cross-sectional size or obtusely quadrangular. Flowering parts bear numerous large, red-orange, owers with terminal in orescences. The thyrses, called panicles, are often up to 45 cm long. The tubular ower is 1.2-2 cm long with ve small lobes. The leaves are opposite, large at the base and becoming smaller upwards; subrotund to cordate at the base, and palmately lobed (3-7) at the margins.

Results And Discussion
Species richness and diversity of the study area Considering the distribution of Clerodendrum paniculatum in several parts of the world as both native and invasive connotes that this novel alien species originates not from Africa, and nevertheless this study reveals where it was found in Africa for the rst time. The different land-use type effects on species distribution and establishment in these new habitats gave us the larger number of species at one site over the other.
The total families are shown in Tables 1 & 2. Twenty-one (21) families were encountered within the Forest Plantation, and fteen (15) in Strict Nature Reserve (SNR).This shows that between the two different sites, the family with the highest number of plant species was found in the legumimosae (Caesalpinoideae, Detariodeae, and Papilionideae) with 7 different plants species. But within the sites, plant numbers from Table 1 show C. paniculatum was the second most abundant plant species, with a relative density of 14.12%, after Sida acuta Burm. F., a native plant, with a relative density of 15.97%. The species comparison between the two tables shows that the proliferation of C. paniculatumwas rather alarming in Table 2. The reason for this rapid growth and distribution may have been associated with what Randhi and Reddy (2013) described as an intermediate, tolerant,plant capacity in their study. Light and spatial distributions are associated factors more incidental toterritorial adaptation and tolerance in the Forest Plantation than in the protected area of the Strict Nature Reserve. This is seen as a result of a partial or closed canopy in Strict Nature Reserve. This dynamic change is in corroboration with Lone et al (2019), which states "invasive species typically are more tolerant than the native species to a wide range of environmental conditions and possess unique biological traits that offer them various competitive advantages." We estimated the Shannon-Weiner diversity index and species evenness for the two sites. The Strict Nature Reserve was less diverse and less even (H'=2.48, E=0.41) than the Forest Plantation (H'=2.9, E=0.48). Most of the species in the Forest Plantation are agricultural weeds (Perera, 2005). n ha -1 = number of stems per hectares, RD = relative density. Although novel species range expansion on these new regions is not invasive, unexpected mass dispersal resulting in expansion of their range (e.g., environmental change) following long time disturbance could quickly lead to invasion. Consequently, Engiberger (2009) reported the phytogeographical scenario of this plant in Oceania: French Polynesia, Guam, Marshall Island, Nauru, Palau Papua, New Guinea, Samoa, and the Solomon Islands. The Federated States of Micronesia lists C. paniculatum as distributed across the islands of Pinpelap, Pohnpei, and Chuuk. Nevertheless, reports of novel alien species colonization in new areascould greatly assist conservation efforts in mitigating invasions at the early stage in Africa. However, little or lack of scienti c information on invasive plant species in developing countries leads to a shortfall in scienti c data for international uses (Nuñez & Pauchard 2010, Nuñez. et al 2019. To overcome this challenge, a collaboration between countries and researchers is needed to address this emerging menace by identifying and sharing scienti c information on novel alien species in different jurisdictions, as well as current best management practices to handle them (Brundu et al 2020).