Who will name new plant species? Temporal change in the origins of taxonomists in China

Abstract

Discovery rates of new plant species need to be accelerated because many species will be extinct before they are formally described. Current studies have focused on where new species may occur and their characteristics. However, who will actually discover and describe these new species has received limited attention. Here, we used 31 576 vascular plant species distributed and described in China as a case study to explore the temporal patterns of the nationalities of the taxonomists. We found that most recently described species are endemic species, and there has been an increasing proportion of species descriptions by resident Chinese taxonomists over time. The proportion of species described by resident taxonomists reached an average of 80.8% between 1977 and 2018. By contrast, species discoveries by non-resident experts, often non-endemic species, showed signs of levelling off. Our study underscores an urgent need for training of, support for and collaboration with resident taxonomists in megadiverse countries with a high potential of discovering undescribed plant species.

1. Introduction

Determining how many plant species occur on earth is a fundamental question in ecology and conservation, with more than 342 000 plants formally accepted since 1753 [1]. However, taxonomy is often biased, with more intensive investigations in developed but species-poor countries where most taxonomists live [2,3]. By contrast, the extent of plant diversity in economically poor but species-rich countries, such as New Guinea [4], may be underestimated due to a lack of available resident taxonomists. To develop a more complete picture of global plant diversity, species discovery rates need to be accelerated in biodiverse countries because many species will be extinct before they are described [5,6].

Previous studies have focused mainly on where new species may occur, and what kinds of species they are likely to be [7,8]. However, who will actually discover and describe these new species has received limited attention. Species yet to be discovered often have smaller range sizes and smaller population sizes than known species, and tend to be locally endemic species found in a particular geopolitical unit [9,10]. In addition, they are more likely to be found in remote, steep and tropical areas that are relatively inaccessible to investigators [7,8]. Because taxonomists often pay more attention to species near at hand [11], and intensive field survey efforts in specific regions demand large amounts of resources and committed time from local experts, future species discoveries and descriptions are likely to depend on resident taxonomists.

Historically, taxonomists from Europe and North America have been major contributors of global species discoveries and formal scientific taxonomic descriptions since Carl Linnaeus’s introduction of binomial nomenclature in 1753 [2,3]. However, there has been a decline in the number of professional collectors and taxonomists from North America and Europe in recent decades [2,12,13]. By contrast, species descriptions by resident taxonomists in some countries such as Brazil, China and Colombia have increased [10,14,15]. For example, 2875 angiosperm species were described from Brazil between 1990 and 2006, and 43.1% of the authors were based in Brazil [15]. A study of species discoveries in the mountains of Iran since 1980 revealed a strong shift of taxonomists describing endemic alpine species from Europeans to resident taxonomists [14]. These studies, although based on small geographical or temporally limited samples, imply there might be a shift over time in the nationalities of taxonomists describing new species from non-resident experts to resident taxonomists. To date, there has been no large-scale and long-term study documenting the origins of plant taxonomists over time, mainly because it has been hard to identify the nationality of the taxonomists who have described particular species for an extremely large dataset.

Herein, we focused on the history of plant descriptions in China. The names of Chinese taxonomists, which are based on Pinyin or the Wade–Giles system, are relatively easy to distinguish from other naming systems [16,17]. Moreover, China is a biodiverse country where collections and descriptions of plant species have taken place continuously and consistently over time [10,18]. Therefore, plant descriptions in China provide a chance to identify the nationality of taxonomists, and to determine whether there has been a shift from non-resident to resident taxonomists over time.

2. Methods

We compiled all plant species included in the Plants of the World Online (POWO; https://powo.science.kew.org/) on 12 August 2020. POWO is one of the most comprehensive information resources for the world's known vascular plants, and it is hosted by Royal Botanical Garden, Kew, UK. We extracted all species formally accepted between 1753 and 2018 with a natural distribution that included China from POWO and used them in our analysis. We excluded 2904 infraspecific taxa (subspecies and varieties) and 264 species with unresolved names.

To avoid the influence of botanical revisions, we used the year of publication of basionyms as the first description date from the primary literature, following Cámara-Leret et al. [4] and Ulloa Ulloa et al. [19]. Information of the basionym species and year of publication of the basionym was determined individually for each plant species according to the International Plant Names Index (IPNI; https://www.ipni.org), Tropicos (https://www.tropicos.org/), POWO and the Plant List (http://www.theplantlist.org/). We did not identify new species with replacement names due to the large amount of data and a relatively small number of these species. In total, there were 31 576 plant species with accepted names in the database (electronic supplementary material, table S1), and for 8277 of them we used the basionyms.

We identified species that had a natural distribution restricted solely to China and considered them to be endemic species. We considered only the first author of a paper who described a given species because the amount of work to assess the nationality of all authors for more than 30 000 species was too large. We determined whether the first author was a resident of China based on her or his family name and given name, including Chinese-origin researchers working aboard. The Chinese language comprises a few family names that are easy to distinguish from those in other countries. For example, 11 common family names, including Wang, Li, Zhang, Liu and Chen are shared by about 40% of the total Chinese population, and about 8.2% of the 13 000 Chinese botanists belong to the Wang family [16]. In addition, Chinese given names are based on one or two characters which are all monosyllabic in Pinyin. As such, the incidence of Chinese names is readily distinguishable from non-Chinese names. To verify taxonomists with unclear nationalities, we checked primary affiliations, or identified them through the author search function in the Tropicos and the IPNI databases. To ensure our results were robust, we also checked the recently published book ‘Chinese Plant Taxonomists’ [20], which compiled detailed information (e.g. names & institutions) of 2862 Chinese plant taxonomists who have been involved in describing and publishing vascular plants.

3. Results

Half of the species in China are endemic species (table 1). Between 1753 and 2018, an average of 119 species was described annually, with a higher species description rate between 1980 and 2018 (average of 197 species per year). The increase in species numbers in the last century was driven primarily by the discovery of endemic species (figure 1); endemic species contributed to 84.3% of all described species between 1950 and 2018 (table 1). While the discovery of non-endemic species showed signs of levelling off (figure 1a), endemic species have continued to be described in high numbers.

Table 1.

Number of described plant species endemic and non-endemic to China by resident and non-resident taxonomists (based on first authors).

time period	named by non-resident taxonomists		named by resident taxonomists
	non-endemic	endemic	non-endemic	endemic
1753–1849	6552	134	0	0
1850–1949	7480	6375	189	595
1950–2018	909	1234	659	7449
all	14 941 (47.3%)	7743 (24.5%)	848 (2.7%)	8044 (25.5%)

Figure 1.

The numbers of species (based on basionyms) that (a) are endemic (light blue) and non-endemic (dark blue) to China, and (b) described by non-resident (green) and resident (orange) taxonomists in a given year from 1753 to 2018.

We recorded 2546 first authors, of which 1028 were Chinese. The number of first authors in a given year was significantly and linearly correlated with the total number of described plant species (figure 2a; d.f. = 263, r = 0.77, p < 0.001). Among these plants, 848 non-endemic species and 8044 endemic species were described by resident taxonomists (table 1). As a comparison, non-resident taxonomists described 7743 endemic species and 14 941 non-endemic species in China, respectively. Chi-squared test indicated that endemic species tend to be described by resident taxonomists (χ² = 8105, d.f. = 1, p < 0.001).

Figure 2.

(a) The relationship between number of first authors and number of described species in a given year between 1754 and 2018 (1753 was removed because of the extraordinary influence of Carl Linnaeus that published 1005 species in that year). (b) The temporal pattern of resident and non-resident taxonomists that published at least one species in a given year as the first author.

Before 1923, all 17 189 plants were formally described by foreign experts, including 4615 endemic species (figure 1b). In our dataset, Huanyong Chen was the first resident taxonomist that described a Chinese plant in 1923. Since then, the number of resident taxonomists has increased rapidly (figure 2b), as has the number of species they have described (figure 1b). By contrast, the number of non-resident taxonomists has decreased since 1942 (figure 2b). As a result, there were more resident taxonomists than non-resident taxonomists in recent decades who have described new species in China. The proportion of species described by the resident taxonomists reached an average of 80.8% from 1977 to 2018, indicating a shift from non-resident to resident taxonomists over time.

4. Discussion

Based on the annual rate of species description, there are still thousands of plant species yet to be described [5,8], even in a country with the compilation of its flora, the Flora of China, completed in 2004. During the last two decades, about 200 new plant species have been described in China annually [10,18]. Similarly, an average of 744 plant species have been described per year in the Americas between 2002 and 2017 [19], and the number of vascular species described for tropical Asia has been growing at an average of 364 per year between 2008 and 2019 [21]. These studies highlight the importance of continued species investigations, collections and descriptions, especially in species-rich countries. Notably, many of these species have been described by resident taxonomists. For example, Dr Ricardo Callejas Posada, a Colombian botanist, was involved in taxonomic publications of 120 new species in 2020, many of which are from Colombia [22]. Between 2000 and 2019, 74.3% of all new vascular plant species described in China were published solely by resident taxonomists [18]. In addition, we found that resident taxonomists have contributed more than 80% of the species descriptions of China in recent decades. This evidence suggests that resident taxonomists in biodiverse countries are starting to play an important role in global species discoveries.

Why are more recently described species more likely to be described by resident taxonomists? It is possible this pattern is related to the decline of the number of taxonomists and active taxonomic institutions in Europe and North America. Historically, European botanists, including Sir Joseph Banks, Alexander von Humboldt and Ernest Wilson, collected tens of thousands of specimens from other parts of the world [23]. These collections were stored in herbaria outside their countries of origin, and the specimens gathered have been described, or are waiting to be described, by foreign taxonomists. Unfortunately, amateur and professional taxonomists in developed countries have declined in number since the 1950s [2,12], along with a decline of species collections in museums and herbaria [13]. This decline was due mainly to limited funding and support for plant taxonomy [24,25]. In addition, increased collection and export restrictions also may have contributed to a decline in foreign taxonomist contributions [24].

Another important factor driving the increasing importance of resident taxonomists may be related to the nature of more recently described species, and species yet to be found. First, newly described species are often small, inconspicuous, rare, and have small range sizes [8,9,19]. They generally also receive limited research attention [6]. As shown in our study, most of these taxa are likely to be endemic species with small populations (figure 1). Second, more recently described species are often ‘cryptic species’ that are morphologically indistinct from their relatives, and these species are commonly found in large, complex families such as Orchidaceae, Asteraceae and Poaceae [10,22], which require professional taxonomists specializing in a particular family to identify them. Third, more recently described species often occur in previously poorly surveyed areas, such as those in remote mountainous areas and tropical rainforests [8,19,21], which are also areas characterized by high investigation costs. Resident taxonomists may be better positioned to overcome these difficulties. They tend to pay more attention to species close by as part of intensive inventory efforts, termed as the ‘botanist effect’ [11], in particular regions [23]. In addition, they can communicate more effectively with local amateurs, paid workers and inventory specialists, who play an important role in species collection, recognition and descriptions [12,26]. Resident specialists in particular taxa are familiar with local species pools and have a strong ability to distinguish new species from their morphologically similar known relatives. There is a trend for increasing specialization on particular groups of taxonomists over time [3]. They can also apply and receive more grants for investigation of local species and compilation for local floras from local governments, and the costs for these local biodiversity investigations are relatively low especially compared to costs for foreign experts to survey the same areas [26]. As such, local taxonomists are more likely to find new species endemic to their home countries.

Our study has important implications for species discovery and biodiversity conservation. More recently described species are often endemic species [9], which are more vulnerable to extinction and may be more sensitive to environmental changes [6]. Unfortunately, hotspots of species discoveries are often threatened by human activities, and many plant species are thought to be critically threatened or even extinct when they were described. An example is the Critically Endangered Torreya dapanshanica, a new conifer species endemic to Zhejiang province, East China, which comprised fewer than 10 individuals when it was described [27]. While it is necessary to send foreign plant taxonomists to the right geographical locations, especially in the tropics [23], our study highlights that training and supporting resident taxonomists to describe their endemic species should be a priority [4]. Specifically, we suggest that support for natural history or the popular science of nature is a key step to prevent ‘plant blindness’ of the general public [28], and to attract and train young generations to study plant taxonomy [26,29]. This support should include para-taxonomist training and professional taxonomy courses supported by experts from botanical gardens, museums, universities and NGOs, as well as cooperative training programs with foreign institutions [4,26]. Notably, botanical gardens and university campuses are often home to plant taxonomists, and plant resources on university campuses in China have been used as an effective tool for teaching plant taxonomy and science popularization [30]. Funding even a small number of experts can disproportionally accelerate species discovery rates [23]. For example, a project that supported professional taxonomists on an orchid diversity survey in China discovered approximately 30 new species between 2019 and 2022 [31]. Therefore, it is critical to provide career opportunities for local taxonomists in species-rich countries and support them with funding, grants and employment. In addition, it is of great importance to establish local natural museums and herbaria for plant collections, and digitalize them for public research [26]. Finally, collaborations with local plant taxonomists and valuing their contributions can promote and support new species discoveries [32].

Based on the analysis of 31 576 known plant species described in China between 1753 and 2018, our result demonstrated that species discoveries by resident taxonomists are increasing and resident taxonomists are playing a more important role in plant species discoveries. However, we also suggest that political changes played an important role in driving the observed pattern. There were sharp decreases in the number of active taxonomists during World War II and the 10-year Cultural Revolution period (1966–1976) (figure 1b). Similarly, the number of newly described plant species in New Guinea declined dramatically during World War II [4]. During politically unstable periods, most domestic scientific research in China stopped, although many new species were identified and described by non-resident taxonomists based on specimens stored in foreign herbaria. Therefore, political instability has negative impacts on new species discoveries and publishing. Overall, China has been a politically stable country for many decades and now supports a large number of well-trained taxonomists. As such, our findings may be applicable to other nations like Australia and Brazil that are characterized by relatively high investments in taxonomy [10,15], but the results may have limited implications for other countries. Many biologically wealthy countries, such as many tropical countries, are poor in natural history collections and support relatively few resident taxonomists [33], furthermore, many of which are suffering from underfunding or unstable political conditions [34]. Together, there are only 121 registered taxonomists for eight megadiverse developing countries, among approximately 5000 international experts globally in the World Taxonomist Database [33]. Therefore, we suggest that further analyses on spatio-temporal patterns of nationalities of taxonomists at the global level are needed. In addition, we suggest that developing countries still need support from developed countries in training resident taxonomists. This includes areas in tropical Africa, South-east Asia and South America, and more international collaboration to better support plant taxonomy is urgently required.

Data accessibility

The data are provided in the electronic supplementary material [35].

Authors' contributions

J.L.: conceptualization, formal analysis, funding acquisition, methodology, resources, validation, visualization, writing—original draft and writing—review and editing; X.J.: conceptualization, data curation, methodology, writing—original draft and writing—review and editing; S.Y.: data curation, resources and writing—review and editing; Y.W.: data curation, resources and writing—review and editing; Y.L.: data curation, resources and writing—review and editing; Q.C.: data curation, resources and writing—review and editing; C.W.: data curation, resources and writing—review and editing; F.S.: conceptualization, supervision, writing—original draft and writing—review and editing; D.L.: conceptualization, supervision, visualization, writing—original draft and writing—review and editing.

All authors gave final approval for publication and agreed to be held accountable for the work performed therein.

Conflict of interest declaration

We have no competing interests to declare.

Funding

This work was supported by National Natural Science Foundation of China grant nos. 32071646 and 32070218 and the Science and Technology Commission of Shanghai Municipality grant no. 22ZR1405600.