Aquatic Botany 173 (2021) 103416 Contents lists available at ScienceDirect Aquatic Botany journal homepage: www.elsevier.com/locate/aquabot The past, current, and future distribution modeling of four water lilies (Nymphaea) in Africa indicates varying suitable habitats and distribution in climate change John M. Nzei a,b,c, Boniface K. Ngarega a,b, Virginia M. Mwanzia a,b, Paul M. Musili d, Qing-Feng Wang b,e, Jin-Ming Chen a,b,* a Key Laboratory of Aquatic Botany and Watershed Ecology, Wuhan Botanical Garden, Chinese Academy of Sciences, Wuhan, 430074, China b Center of Conservation Biology, Core Botanical Gardens, Chinese Academy of Sciences, Wuhan, 430074, China c University of Chinese Academy of Sciences, Beijing, 100049, China d East Africa Herbarium, National Museums of Kenya, P.O. Box 451660-0100, Nairobi, Kenya e Sino-Africa Joint Research Center, Chinese Academy of Sciences, Wuhan, 430074, China ARTICLE INFO ABSTRACT Keywords: Mapping and modeling suitable habitat and distribution of aquatic species is important to help assess the impact Nymphaeaa of factors such as climate change in affecting the shift, decline, or expansion of species habitat ranges. In Africa, Climate change the distribution of water lily (Nymphaea) species is geographically varied and the habitats suitable for individual Species distribution species are prone to effects of global warming, though only limited conservation measures have been taken to Temperature and precipitation date in aquatic environments. In this study, four widely distributed water lily species (N. nouchali, N. micrantha, Africa N. lotus, and N. heudelotii) were modeled using MaxEnt which highlighted the individual species’ suitable cli­ matic distribution. The current distribution indicates a partial distribution of N. nouchali in West Africa unlike N. micrantha, N. lotus, and, N. heudelotii. Nymphaea lotus displays wider distribution in West, East, and parts of South African countries including their coastlines compared to all other species. Nymphaea nouchali indicates dense distribution in countries South of Africa while N. micrantha and N. heudelotii in West African countries. Greater habitat changes were noticed between the future and the past projection due to limited range expansion in 2.6, 4.5, and 8.5 (2050) Representative Concentration Pathways (RCPs) in almost all species. The species’ suitable habitat distribution was mainly influenced by nine variables, mostly the temperature and precipitation variables. This study provides projections of future climatic scenarios potentially influencing the distribution of Nymphaea species in Africa, which may be useful for the ongoing conservation and management of these plants especially in areas loosing suitable climatic conditions. 1. Introduction 2016). This rate of decline has been linked to human over exploitation of resources through agriculture, water extraction, flow regulation, the Aquatic and wetland ecosystems have become a center for major introduction of new species, and ecosystem pollution. Ultimately this activities that influence species suitable habitat areas and the natural has translated to the decline in abundance and distribution range of population. The prioritization of the ecosystems for economic impor­ freshwater species and thus a steep rise of global biodiversity threats tance such as in agriculture and domestication of some freshwater spe­ (Dudgeon et al., 2006), and the most influencing factor is climate cies in different parts of the world for their economic value has increased change, and specifically global warming, which has raised the global downstream chances for invasive species distribution from water flow surface temperature to approximately 0.6 ℃ over the past century and flooding( Wu and Ding, 2019). It is estimated that approximately 81 (IPCC, 2001) and by 2100 it is projected to increase by 4.3 ± 0.7 ℃ % of the world’s freshwater ecosystems have been lost between (IPCC et al., 2013). 1970–2012 at a rate of 3.9 % per year (The World-Wide Fund for Nature, Although species have evolved and adapted in their habitat areas in * Corresponding author at: Key Laboratory of Aquatic Botany and Watershed Ecology, Wuhan Botanical Garden, Chinese Academy of Sciences, Wuhan, 430074, Hubei, China. E-mail address: [email protected] (J.-M. Chen). https://doi.org/10.1016/j.aquabot.2021.103416 Received 18 December 2020; Received in revised form 4 June 2021; Accepted 8 June 2021 Available online 12 June 2021 0304-3770/© 2021 Elsevier B.V. All rights reserved. J.M. Nzei et al. Aquatic Botany 173 (2021) 103416 response to the changing climate, the effects are likely to accelerate in RCP 2.6 (stringent mitigation scenario), RCP 4.5 (intermediate scenario) the future causing substantial effects to species adaptation and habitat and RCP 8.5 (high greenhouse gas emission) scenarios of the Interna­ distribution, causing biological inversions and unidirectional movement tional Panel of Climate Change (IPCC5) of the fifthreport (IPCC 2014), of the species depending on the species community (Kelly and Goulden, with the aim of (i) determining the potential contribution of climatic 2008). This is without the exception of inland aquatic systems (Dudgeon variables in the distribution of Nymphaea species, (ii) determining et al., 2006), consisting of the freshwater ecosystems that holds suitable climatic habitat and (iii) suitability changes from the current approximately 1% of the Earth’s surface and 10 % of the current distribution. documented species (Strayer and Dudgeon, 2010). Moreover, with the simulated increase of temperature, extinction risk will rise to 8.5 % 2. Materials and methods when the earth warms to 3 ℃ thus losing one in every six species (Urban, 2015). Therefore, the consequences of climate change will not be limited 2.1. Occurrence records to individual species life history patterns and distribution ranges, but there will be an increased loss of biodiversity, habitat fragmentation, The species distribution modeling focused on all the available and change of spatial patterns of plant species (Warren et al., 2018). occurrence records obtained from the Global Biodiversity Information For that reason, the use of climate change models provides insight Facility (GBIF, http://www.gbif.org/), RAINBIO database (Dauby et al., into species potential biogeographic distribution habitats under threat 2016), published work of Kennedy et al. (2015), and fieldworkvisits to (ranges under contraction) and possible conservation areas (stable Africa (July 2018- May 2019) (Table S1). In this study, the occurrence ranges and ranges under expansion) (Chen and Peterson Townsend, records for Nymphaea nouchali subspecies caerulea (Savigny) were 2002). This information plays a crucial role in species monitoring and included within the parent species N. nouchali (Burm.f.). Hereafter all proper conservation, especially on threatened habitat ranges. Also, they these records are referred to as Nymphaea nouchali. This is because the contribute to the decisions made by policy makers and conservation majority of the occurrences were obtained from GBIF with the infra­ biologists concerning species management and protection (Hendry species having the same geographical extent. Also, some occurrences et al., 2010). Further, it is important in planning for today’s species shared similar coordinates an indication that different collectors might niche conservation and projection of their future distribution under have confused the identificationif not found at the same location. Since global warming (Wan et al., 2020). we could not ascertain with confidence such discrepancies, we consid­ Nymphaea is a cosmopolitan genus with species inhabiting shallow ered the two species together. Duplicate occurrence points were then and freshwater ecosystems in tropical temperate areas. The species are removed and projected in a google distribution map for each species to considered valuable because of varied factors: (i) they are considered as correct any possible geographical error by manually discarding the valuable ornamental plants because of their diversity in flower colors points with obvious geocoding errors and those that cannot be geore­ and ability to survive indoor conditions (Chen et al., 2017), (ii) they ferenced to the nearby wetland or freshwater ecosystem. Country cen­ produce valuable chemicals in medicine and cosmetology such as fla­ troids were also removed to avoid sample bias. Then the occurrence vonoids, alkaloids and tannins used in the treatment of diabetes, liver points were rarefied to a distance of not less than 10 km between each inflammations and urinary infections and many more complications other using SDMTools in ArcGis (Jackson et al., 2000) to minimize (Archana and Ashwani, 2016), and (iii) they are used in water purifi­ autocorrelation (Fig. 1). A total of 398 geographic points representing cation from heavy metal and soap contamination (Tani et al., 2006). occurrences for N. nouchali Burm.f., 442 for N. lotus L., 137 for In Africa, water lily (Nymphaea) species in the subgenus Brachyceras N. micrantha Guill. & Perr., and 23 for N. heudelotii Planch. was obtained and Lotos appear to have a wider distribution than other species in the indicating a variable distribution within the African continent genus (Lohne¨ et al., 2008). Although some parts of the continent are (Table S1). poorly sampled (Murphy et al., 2019), the species are geographically variable probably driven by climate change. Currently, the majority of