Detecting the distribution of and public attitudes to charismatic alien species based on media coverage

1.   Introduction

Understanding the spatial distribution, population dynamics, and public awareness of alien species (AS), which pose a potential threat to native ecology and biodiversity, is the foundation for effective management. With high public attention, charismatic species often appear in media coverage, providing information for detecting their spatiotemporal dynamics as well as public perception about the species and management policies (Galaz et al., 2009; Ladle et al., 2016; Du et al., 2024). While people’s love for charismatic AS can be a hindrance to management, timely availability of such information is particularly important for designing dynamic and publicly popular management measures for AS (Ahmed et al., 2022; Caley and Cassey, 2023).

Although high attentions have been paid to the alien invasive species, there is often a lack of early detection of AS before exhibiting invasiveness (Wallace and Bargeron, 2014; Gervazoni et al., 2023). When the population is small and distributed in a limited area, AS do not exhibit obvious impacts on local biodiversity and the environment, and thus is generally overlooked. However, along with population increase and expansion, some AS can become alien invasive species and cause large ecological and socioeconomic losses (Wan et al., 2011; Doherty et al., 2016; Du et al., 2023). Since alien invasive species control often requires a large amount of investment, early detection of AS is important for rapid and cost-effective prevention before they have widely spread (Wallace and Bargeron, 2014; Faulkner et al., 2020; Ahmed et al., 2022; Gervazoni et al., 2023; Zhang et al., 2024). Charismatic AS often have economic, ornamental, or socio-cultural value, and receive high levels of public and media attention by the public and the media (Jarić et al., 2020; Du et al., 2024). Thus, media coverage on the introduction, spread, and breeding of AS provides clues for the prevention and control of AS.

The spread of charismatic AS is often related to the behavior of the public (Byerly et al., 2018; Jarić et al., 2020). For example, the Red-Eared Sliders (Trachemys scripta), one of the worst invasive species worldwide, have been kept as pets in many countries and the establishment of wild populations is mainly due to the escape and release of captive individuals (Ramsay et al., 2007; Du et al., 2024). In Asia, the longevity of turtles gives them cultural charm and makes them a main species of prayer release activities, further facilitating their spread in the wild (Ramsay et al., 2007; Du et al., 2024). Therefore, understanding the public’s attitudes and increasing public awareness are important for AS management (Shackleton et al., 2019; Jarić et al., 2020). Media coverage reflects public perception, guides public behaviors, spreads scientific knowledge, and thus provides information for AS management.

In China, Black Swan (Cygnus atratus) is a charismatic AS with high attention by the public and the media. There are three native swan species including Mute Swan (Cygnus olor), Tundra Swan (Cygnus columbianus), and Whooper Swan (Cygnus cygnus) in China (Ma and Cai, 2000). With pure white feathers and graceful postures, swans are beloved birds and are symbolized as loyalty, purity, and nobility in traditional Chinese culture. There have been numerous poems, songs, painting, and art works about swans since ancient times (Ma and Chen, 2018). The Black Swan is native to Australia, and in China, many zoos and some farms raise them as ornamental birds and special economic animals. In recent years, there have been increasing records of free-living Black Swans in the wild in China (Zhong et al., 2021). With large bodies and graceful postures, Black Swans are easily discovered and identified by the public. The black feathers and red bill, which are different from native swans, add a sense of mystery and attract public and media interest (Zhong et al., 2021).

However, Black Swans have high risk of becoming alien invasive species (Anselin et al., 2011; Dyer et al., 2017). Because of their large bodies, they lack natural competitors and can outcompete other waterbirds. Their herbivorous diet ensures they are not limited by food resources. Black Swans can use diverse water habitats, including lakes, rivers, reservoirs, and estuaries. Moreover, Black Swans have a lifespan of several decades and can lay two nests per year under natural conditions, which enables rapid population increase (Carboneras and Kirwan, 2020). These traits make it easy for Black Swans to form natural populations and rapidly expand in the wild. Following introductions, Black Swans have established natural population in many countries worldwide (Dyer et al., 2017). The alien Black Swans can hybridize with native swans, destroy local vegetation and economic crops, attack native birds and even people (Banks et al., 2008; Dubois, 2007). Nevertheless, it is unclear of the number and distribution of the Black Swans in China, as well as the public attitudes towards the species. This causes knowledge gaps in the management of this potential alien invasive species.

In recent years, digital approaches involving analysis of large bodies of media provide valuable tools for detecting distribution and public perceptions of species with high public attention (Galaz et al., 2009; Ladle et al., 2016; Yan et al., 2024). In this paper, we surveyed the distribution and public perceptions to Black Swans according to media coverage in Chinese mainland. We also collected media coverage on AS and compared the differences in public sentiment and media attitudes towards Black Swans and AS in general.

2.   Materials and methods

To detect the number and distribution of Black Swans in Chinese mainland, we used Baidu (www.baidu.com), the most popular web search engine in Chinese mainland, to search information about “Black Swans” up to December 31st, 2022. The search keywords also included the name of each administrative region at provincial level. We excluded the “Black Swan event”, which was unrelated to this study. We read each report to extract the site name and type (nature reserve, campus, park and scenic spot, residential area, etc), year of introduction, and number of Black Swans. We also recorded the source of birds, whether birds breed at the site and how the offspring were treated, public attitudes towards Black Swans, and date of the reporting. If the year of introduction was not mentioned, the year of reporting was used as the year of introduction. We excluded captive Black Swans in zoos and farms. To ensure the reliability of search results, only reports from news and articles (including self-media articles) were collected, while information from personal sources (such as posts and personal Weibo) was not included. A total of 1028 reports were collected. For multiple reports on the same sites, we retained the number of Black Swans at the latest reporting. If Black Swan number was not mentioned, we estimated the minimum number based on the reports (including photos). Therefore, the number and distribution of Black Swans reported here are conservative estimates.

To detect the emotional tendency of the public to Black Swans in China, we used selenium to drive a headless browser to collect search links obtained from Baidu search engine using the same keywords that were used in manual reading. We then used Python network request library requests to crawl the contents in all the search links. Using the formatting information processing library Pandas in Python, we analyzed the emotional tendency of reports according to keyword analysis. Based on manual reading of the reports, we identified “improvement of environment/ecology”, “protected animal”, “key protection species”, and “good environment/ecology” as positive emotional tendency, while “alien species/animal/bird”, “non-native”, and “invasion” as negative emotional tendency.

To compare the emotional tendency of the public to Black Swans and AS in China, we used the same method to search for media reports on Baidu search engines using the keywords “alien/introduced/non-native species”. Reports with keywords of “improvement”, “benefits”, “development”, “technology”, and “increase of biodiversity” as positive emotional tendency, while “invasion”, “harm”, “destruction”, “threat”, “disaster”, and “risk” as negative emotional tendency.

To understand the media’s attitudes to Black Swans and AS in general, we used unsupervised Latent Dirichlet Allocation (LDA; Hoffman et al., 2010) to extract the topics and keywords in the media coverage from WiseNews, the largest Chinese news database, about Black Swans in Chinese mainland from 2000 to 2022. Before analysis, we removed irrelevant news through manual interpretation, segmented the text, and removed stop words. The number of generated topics gradually increased from two. Ten keywords with the highest relevance to the generated topics were checked. When the overlap rate of n + 1 topic was higher than that of n topic, n was selected as the optimal topic number to obtain keywords in each topic. Similarly, LDA was also used to analyze news about “alien/introduced/non-native species”.

All the phrases and keywords about emotional tendency and attitudes were double checked by different authors to avoid differences in understanding.

3.   Results

3.1   Black Swans in Chinese mainland

A total of 6654 Black Swans at 711 sites were collected from the media coverage by manual reading till the end of 2022 (Appendix Table S1). Birds were found in all the provinces in Chinese mainland except the Xizang Autonomous Region. In terms of both numbers and occurrence, Black Swans were mainly distributed in eastern, central, and southern China (Fig. 1).

Figure  1.  Heat map of the reported number and distribution of free-living Black Swans in Chinese mainland.

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Most Black Swans (5397 birds, 81.0% of the total) were reported in parks and scenic spots (407 sites), followed by the campus of universities and schools (695 birds at 115 sites). Some residential areas also raised Black Swans (124 birds at 32 sites). Surprisingly, a total of 147 Black Swans were reported at 30 nature reserves (Fig. 2).

Figure  2.  Total site number and bird number in the reports about Black Swans in Chinese mainland.

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Among the 561 sites that reported the origin of Black Swans, active introductions were reported at 288 sites (51.3%), including 3 nature reserves. Black Swans at other sites (273, 48.7%) were escaped and spread individuals. Successful breeding was reported at 177 sites (24.8% of the total), including 5 nature reserves. Among the 129 sites that mentioned the offspring, most sites allowed the offspring to live in situ without any management measures (125, 96.9%). Moreover, a small number of sites (7, 5.4%) planned to transfer the offspring to other sites. There was no report of dispersal restriction, such as feather trimming, on the adults and offspring.

Over the past 20 years, the number of reports on the introduction and dispersal of Black Swans exhibited an increasing trend (Fig. 3). There were no more than ten reports per year before 2010, but this increased to 70 or more per year after 2017 and more than 120 per year in both 2021 and 2022 (Fig. 3).

Figure  3.  The number of reports on Black Swan introduction and dispersal in different years. The dashed line shows the exponential regression: number of reports = 1.68 × e^{0.22 ×year}, z = 23.25, p < 0.001. We assigned Year of pre-2004 = 1, Year of pre-2004 = 1, Year of 2004 = 2, and so on in the equation.

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3.2   Emotional tendency to Black Swans

Among the total 200 reports with emotional tendency to Black Swans from manual retrieval, 196 (98%) had positive and four (2%) had negative emotional tendency. Of the 29 reports to Black Swans in nature reserves, only one report (3.4%) exhibited negative emotional tendency. The results from crawler extraction were similar: among the 6994 reports with emotional tendency according to keyword matching, 6740 reports (96.4%) had positive and 254 reports (3.6%) had negative emotional tendency.

LDA analysis indicated that among the 1634 news articles about Black Swans from the WiseNews database, the optimal number of topics was two, both topics exhibited positive emotional tendency, suggesting positive emotional tendency being dominant in media towards Black Swans (topics 1.1 and 1.2 in Table 1). We found some media confused Black Swans with native swans and considered Black Swan as a national key protected species; some media used the appearance of Black Swans as a symbol of improvement of local environmental conditions. We did not find reports on negative effects of Black Swans on local ecology and environment. Although a few media reports indicated that Black Swans were not native in China, most of them focused on the rarity and preciousness without mentioning about the risk of biological invasion.

Table  1.  The topics and keywords from latent Dirichlet allocation analysis on the media reports about Black Swans and alien species.

Topic	Keywords
1. Reports about Black Swans
1.1	Zoo, find, staff, park, citizen, protection, animal, hatch, juvenile, little swan
1.2	Park, find, animal, zoo, egg, juvenile, protection, staff, wetland, hatch
2. Reports about alien species
2.1	Cultivation, variety, base, higher, dendrobe, development, agriculture, technology, mu, pumpkin
2.2	Cultivation, variety, plant, growth, biology, higher, ecology, introduction, technology, market
2.3	Cultivation, invasion, turtle, expert, release, biology, agriculture, find, citizen, industry
2.4	Invasion, plant, quarantine, China, variety, find, biology, department, cultivation, inspection
2.5	Cultivation, Yuan, mu, panda, base, success, development, villager, plant, farmer
2.6	Cultivation, variety, plant, base, mu, agriculture, Taiwan, fruit, success, vegetable

 | Show Table

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3.3   Emotional tendency to alien species

Crawler extraction yielded a total of 52,879 reports on AS that exhibited emotional tendency, including 44,939 (85.0%) with positive and 7940 (15.0%) with negative emotional tendency. Similarly, LDA analysis indicated that positive and negative emotional tendency accounted for 71.0% and 29.0% of the 3330 news articles related to AS in the WiseNews database. The highest proportion of negative emotional tendency occurred in 2022 (60.4%), followed by 2012 (45.6%) and 2021 (40.7%) (Fig. 4).

Figure  4.  Proportions of news with positive and negative emotional tendency to alien species in 2000–2022 based on latent Dirichlet allocation analysis. The numbers of news in each year are shown above the bars.

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The optimal number of topics from LDA analysis was six, which can be divided into positive and negative topics based on keywords. Positive topics were related to the cultivation of introduced crop varieties (topics 2.1, 2.2, 2.5, and 2.6 in Table 1); negative topics were related to biological invasion, including release of alien invasive species and quarantine of AS) (topics 2.3 and 2.4 in Table 1).

4.   Discussion

Based on information in media coverage, we analyzed population status of and public perception to Black Swan, a charismatic AS in Chinese mainland. We found that in the past 20 years, the distribution of Black Swans expanded rapidly through active introduction and natural spread. Black Swans have established natural breeding populations at many sites, including some nature reserves. Both the public and the media exhibited overwhelmingly positive emotional tendency to Black Swans, which was higher than that to AS in general. These results suggest that the Black Swans have high risk of becoming alien invasive species but the public and the media are unaware of this.

4.1   Distribution of Black Swans in Chinese mainland

Charismatic species often have special traits such as large body size, bright colors, and unique morphology, which make them easily detected by the public and thus feasible targets for citizen-science monitoring (Jarić et al., 2020). Because of Black Swans’ easy recognizability and high media attention, the information we collected in this study is guaranteed to be reliable. However, Black Swans may be overlooked in some remote areas lacking media coverage and attention. Moreover, we recorded the minimum when the number was uncertain at each site. Therefore, the number and distribution of Black Swans presented in this study are conservative estimates. Even so, more than 6000 individuals at over 700 sites have been reported, and successful breeding have occurred at a quarter of the sites. The number of distribution sites has also steadily increased in recent years. All these points suggest that Black Swans have established self-sustaining populations and are expanding rapidly at many sites. We did not find reports on ecological and environmental harm caused by the Black Swans in China, which may be related to their small populations at most sites. With continuous population increase and distribution expansion, however, Black Swans may cause adverse impacts on local ecology and biodiversity, becoming an alien invasive species in China. This issue warrants increased attention from the management agencies.

We found that Black Swans were mainly distributed in the eastern, central, and southern China. This may be due to the mild climate and widely distributed water bodies that provide suitable habitats for swans (Ma and Chen, 2018). Moreover, this region contains dense human populations (Li et al., 2017). This suggests the spread of Black Swans may be related to human activities. Black Swans are non-migratory, thus all the birds in the field came from active introduction or spread from surrounding areas. Swan introductions may be more common in regions with dense population and suitable environment.

4.2   Public and media attitudes to Black Swans and alien species

We found that both the public and the media exhibited overwhelmingly positive emotional tendency towards Black Swans in China. Moreover, the proportion of reports with negative tendency was higher to AS than that to Black Swans. Both suggest that most public and media are concerned about the cultural and aesthetic value of Black Swans, while remaining unaware of their AS attributes. This also implies the emotional tendency towards the abstract concept of AS and their invasion risk are decoupled from the genuine feelings towards specific beloved AS, reflecting the insufficient public awareness of biological invasion risk.

In 2012, 2021, and 2022, the proportions of negative emotional tendency to AS were higher than that in other years in the media coverage. This might be related to the increased attention to the negative impacts of AS: In 2012, a person was bitten by the Piranha (Pygocentrus nattereri), an alien fish in Guangxi, attracting the public and media attention to the threats of AS (Xinhua News Agency, 2012). In 2021, the “Biosafety Law of the People’s Republic of China” was implemented; In 2022, the “Checklists of Invasive Alien Species under Key Management” (Ministry of Agriculture and Rural Affairs, 2022a) and the “Measures for the Management of Invasive Alien Species” (Ministry of Agriculture and Rural Affairs, 2022b) were released. These events may increase the reports about the negative impacts of AS in media.

4.3   Invasion risk and management of Black Swans in Chinese mainland

We found increasing reports of active introductions, escaped individuals, and natural breeding records of Black Swans in recent years. However, no population control measures were reported. In September 2021, a Black Swan even appeared on Tiananmen Square in Beijing (Beijing Daily, 2021). This may be related to the wide distribution of Black Swans nearby: From 2020 to 2022, Black Swans were reported at 26 sites including escaped birds at 16 sites in Beijing (Appendix Table S1). In addition, charismatic species are more likely to obtain public assistance, such as artificial feeding, which also help their successful settlement at new distribution area (Jarić et al., 2020). With a long-standing cultural and aesthetic value of swans, feeding Black Swans is common in China. Moreover, global warming also benefits the expansion of suitable distribution area. All these suggest that Black Swans are likely to continuously expand in China in the future. At present, Black Swans have not shown obvious impacts on native biodiversity and the environment in China, likely due to their small population at present. As their population expands, Black Swans may exhibit negative impacts in the future.

The Chinese government has attached great importance to the management of alien invasive species, many legislations and regulations have been issued over the past 20 years (Wan et al., 2008; Xinhua News Agency, 2020; Ministry of Agriculture and Rural Affairs, 2022a; 2022b). However, there is a still management gap for AS that have been introduced but not exhibited invasiveness (Wan et al., 2008). In China, raising Black Swans is legal with a “Domestication and Breeding License for Non-State Key Protected Animals” and a “Wildlife Operation License”. There is no special requirement for raising AS, such as implementing escape prevention measures. This management gap should be filled. It is worth noting that Black Swans have already occurred in many nature reserves through natural spread and active introduction, and established breeding populations in some ones. Nature reserves are the cornerstones of native biodiversity and ecosystem protection. Greater attention should be paid to the potential negative effects of Black Swans on nature reserves.

4.4   Public and media awareness to charismatic alien species

Understanding potential misconceptions and context is important to maximize the social impacts of conservation and management (Benford and Snow, 2020). Although the harmfulness of alien invasive species has been widely recognized, potential invasion risk of charismatic AS is often overlooked by the public (Jarić et al., 2020; Du et al., 2024). Public perception is culture-dependent, and it can also be modified through targeted activities (Bremner and Park, 2007; Veríssimo et al., 2017). Public awareness activities to promote cognitive linkages between the risks and charm of AS could help induce public support and participation in AS control actions (Jarić et al., 2020).

Media coverage plays an important role in raising public awareness. However, we found most media are unaware of the attributes of AS and the potential hazards of Black Swans. The overwhelmingly positive emotional tendency in reports likely guide misperceptions among the public, promoting the introduction and spread of Black Swans. This might be related to the fact that most media staff and journalists lack knowledge about alien invasive species. Therefore, it is critical to improve awareness and knowledge within media organizations themselves.

We found that the Black Swans have spread rapidly and distributed widely in Chinese mainland over the past two decades. This leads to high risk of biological invasion and thus effective control measures should be timely taken to prevent population increase and dispersal in the wild. Population dynamics of Black Swans in the wild should be monitored and timely removal of birds within nature reserves is required to protect native biodiversity. It is important to raise public awareness of the potential risks of charismatic AS and thus to avoid intentional introduction. We emphasize the need to enhance the scientific literacy of the media, thus can guide the public behavior correctly.

Our results indicate that media coverage provides important clues for detecting the distribution of charismatic species, which helps rapid assessment of large-scale population dynamics. Media coverage reveals public perception and reflects attitude and policies of authorities, both of which are central to the practice of conservation and management. The methods used in the present study may also be referred to for research on other species with high levels of public attention.

CRediT authorship contribution statement

Yuexuan Liu: Data curation, Formal analysis, Investigation, Methodology, Software, Visualization, Writing – original draft. Ruichang Sun: Data curation, Formal analysis, Methodology, Software, Visualization, Writing – original draft. Bo Li: Funding acquisition, Supervision, Writing – review & editing. Zhijun Ma: Conceptualization, Methodology, Project administration, Resources, Supervision, Visualization, Writing – original draft, Writing – review & editing.

Declaration of competing interest

The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper.

Acknowledgements

We thank Renli Chen for her help in data collection and Francis Commercon for his comments and language editing.

Appendix A. Supplementary data

Supplementary data to this article can be found online at https://doi.org/10.1016/j.avrs.2024.100201.