Biotic homogenization in the availability of ornamental seeds of the native flora in Chile

Abstract Biotic homogenization is a global phenomenon, mainly in urban areas where exotic species are dominant, contributing to the loss of native biodiversity. Gardening native flora to promote local biodiversity is becoming a conservation practice in urban settings. Therefore, in this study, we analyzed the representation of the Chilean native flora in the Chilean and international ornamental flower seed market to know which native plant seeds are sold. We found that native seed are absent in the local market and that the totality of seed supply in the market corresponds to species of exotic origin, mainly from the Palearctic region (43%). However, surprisingly, many Chilean flower seeds are traded in the international market (approximately 6% of the total Chilean flora). This lack of availability of native seeds for local consumers constitutes a bottleneck for ecological restoration initiatives. It is consistent with the greater abundance of exotic species in urban green areas and supports the hypothesis of biocultural homogenization.


Introduction
Biotic homogenization is a global phenomenon, mainly in urban areas where exotic species are dominant at the expense of native species, contributing to the loss of native biodiversity (McKinney, 2006).This phenomenon is particularly relevant since today, 56% of the population lives in cities (The World Bank, 2022), and this trend is expected to continue, especially in Latin American countries rich in biodiversity, which have the highest percentage of urban population in the world (Rozzi, 2015).However, urban green spaces and residential gardens may be an essential reservoir of native biodiversity in an urbanized world (Goddard et al., 2010).Thus, in these green spaces, local seeds mixes can be an effective method for improving the biodiversity of plants or higher-level trophic organisms, such as native pollinators (Braman et al., 2002;Harmon-Threatt and Hendrix, 2015;Baldock et al., 2019).
The native flora of Chile consists of 4,655 species, of which almost half (n = 2,145) are endemic (Rodríguez et al., 2018).A recent revision of the useful native plants of Chile estimated that at least 300 species have ornamental uses, and 417 native species have been recommended as having the potential for ornamental use (Díaz-Forestier et al., 2019).Moreover, León-Lobos and Rosas (2010) estimated that 586 native species are sold as seedlings or seeds outside Chile in the international market.Many of these species have been traditionally used ornamentally in foreign countries, mainly in the United Kingdom, the United States of America, Japan and Holland (Gardner, 2001;Teillier, 2008).
Despite their benefits and international interest, native species are rare in Chilean nurseries (León-Lobos and Rosas, 2010) and Chilean urban green spaces (Figueroa et al., 2018, Varas et al., 2020), with exotic species predominating over native ones (Rozzi et al., 2003;Santilli et al., 2018;Varas et al., 2020).This substitution and uniformity of local biota diminish people's in-person encounters with local biodiversity, promoting biocultural homogenization related to the process of "extinction of experience" (Soga and Gaston, 2016).
Research on urban flora has focused mainly on analyzing the flora's diversity, ecological interactions, and landscape attributes and has rarely considered the availability or supply of seeds in the retail market, which could be a relevant constraint to its ornamental application.However, in recent decades, both, the increase in specialized stores and the sale of seeds in retail stores, in addition to a higher interest in gardening, have increased the availability and demand for seeds for their use in private and public gardens or even in agricultural areas to improve the landscape and to promote local biodiversity.For example, the use of floral band to attract pollinators implemented in Santiago urban parks (El Mercurio, 2022) and in rural areas (Muñoz et al., 2021a).
Therefore, this study aims to evaluate the representation of Chilean flora in the ornamental seed market in Chile to implement conservation practices.Our specific questions are: i) which native plant seeds are sold in the Chilean market?and ii) which native plant seeds are sold in the international market?

Material and Methods
In 2020, we reviewed the catalogs of the leading retail companies in the gardening market in Chile, which represent 90% of the official Chilean market retail companies, in addition to widely distributed in the country, small gardening dealers' companies (Table 1) to determine the seed species that are formally sold.We reviewed information only from formal markets, understanding that there is an informal market, often not legal and that it lacks adequate traceability of the origin of the seeds.The identified species were classified according to their taxonomy, origin and biogeographical region of origin (sensu Wallace, 1876), commercial name and commercial company.
Table 1.Retail companies in the gardening market in Chile, where we looked for seed species that are formally commercialized.It is important to note that some websites informally sell seeds of many native species or offer them to promote native flora for gardening.However, because of the informal nature of this market, there are no reliable data available, and they were not considered in this study.With regard to the international market, we reviewed the 5 th (2002) and 8 th (2012) editions of the "Seed search" catalog, which contains the last updated record of all the seed species (with their scientific name) and companies that sell seeds formally in the international market.The taxonomy of the species was updated according to the vascular plants of Chile catalog by Rodríguez et al. (2018).The species were organized according to their taxonomy, commercial company and country.
It was found that the families and genera of the exotic seeds sold in Chile are highly represented in the Chilean flora; 90% (n=19) and 51.4% (n=35) of the families and genera respectively (Figure 2a).
According to the international market, 290 Chilean species are formally sold in the seed market, including 73 families, 155 genera, 160 native and 130 endemic species (Tables 3 and 4).Approximately 6% of the total native flora is sold in the international seed market (Figure 2b), including less than half of the Chilean plant families (39%).The most common families were Cactaceae (n = 46 species) and Alstroemeriaceae (n = 18 species), and among the genera, Eriosyce (n = 23 species) and Alstroemeria (n = 16 species) were most frequently found in the international seed market.
Regarding the companies, we found 155 companies from 21 different countries that sell Chilean seed species (Table 5), with England (34%) and the USA (32%) selling the most species of all the companies.None of these companies have businesses or representation in Chile.Most of the Chilean seeds were sold internationally by companies such as B&T World Seeds (n = 117), Chiltern Seeds (n = 90) and Sandeman Seeds (n = 79).

Discussion
The results allow us to see an uneven availability of seeds from native ornamental plants, because native seeds are absent in the formal Chilean seed market, but surprisingly, approximately 6% of Chilean flora are currently sold as seeds in foreign countries.These results are in line with the low representation of native Chilean flora at local plant nurseries, and this trend has not changed in the last decade (León-Lobos and Rosas, 2010).Notably, some endemic and endangered species are commercialized in other countries but not in Chile, such as representatives of the genus Copiapoa (Cactaceae), and endemic species such as Jubaea chilensis (Arecaceae) and Peumus boldus (Monimiaceae).This issue represents an important challenge to valuing these species for gardening in Chile, generate demand, and thus promote the interest of local nurseries (Table 4).
England has the largest number of companies that offer Chilean native seeds (n=52) because British interest in Chilean species date from the early years of the 19th century (Maxwell and Gardner, 1997;Teillier, 2008).Outside Chile, Cactaceae is the most sold family, and half of these seeds belong to the genus Eriosyce, with almost all species endemic to Chile (22 out of 23 -Table 3).This family has desirable ornamental traits for gardening worldwide (Nobel, 2002) and has attracted great interest in terms of private collections.Interest that should increase due to its low water requirements and future climate change scenarios.However, many of these species are currently threatened by illegal harvest.Therefore, it is urgent to establish a formal market for properly collected and cultivated seeds and plants, allowing their origins to be traced, especially because there is an informal seed market.
The existence of a formal market helps to reduce illegal trade in species and to comply with the standards of the Convention on International Trade in Endangered Species of Wild Fauna and Flora (CITES).Therefore, further studies should aim to quantify these informal markets, particularly foreign markets, to estimate the unregulated leakage of genetic material since Chile is a signatory to CITES and the Convention on Biological Diversity.
The availability and access of native seeds and flora has implications for ex situ biodiversity conservation.It enables their use in local ecological restoration programs, in ecological intensification such as cover crops in agricultural areas, and in urban green areas (Harmon-Threatt and Hendrix, 2015;León-Lobos et al., 2020).For example, in many times, the re-establishment of native plant species is hindered by the lack of availability of a suitable soil seed bank or nearby source area for recolonization.Therefore, the availability of native seeds is a key to ensuring successful restoration (Elzenga et al., 2019).Recent research highlights the use of native flowering shrubs to promote beneficial insects in commercial crops, which result in an increase of crop productivity (Muñoz et al., 2021a(Muñoz et al., , 2021b)).
However, there is limited availability of native plants in commercial nurseries, that difficult for their implementation in agriculture (Bannister et al., 2018).In this context, León-Lobos et al. (2020) proposed that the lack of adequate seed supply is a major bottleneck for effective ecosystem restoration in Chile.Additionally, using native seeds for ornamental purposes in urban green areas could increase knowledge and concerns about local biodiversity, affecting awareness and positive attitudes toward their conservation (Parra-Saldívar et al., 2020), in addition to promoting ecological interactions among native species.Biocultural homogenization (Celis-Diez et al., 2017), which involves not only a substitution and uniformity of local biota (biotic homogenization), but also the loss of awareness and willingness to conserve local nature due to the "extinction of experience" or the lack of face-to-face encounters with local biodiversity (Soga and Gaston, 2016), constitute an understudy driver of global change.A possible explanation is the lack of information about seed sourcing, seed quality/ availability, processing and storing seeds, dormancybreaking, and germination (Elzenga et al., 2019;León-Lobos et al., 2020), which limit their propagation and trading.

Conclusions
Native flora has great potential to be incorporated into the formal seed market to help promote local biodiversity, reduce biocultural homogenization and increase awareness and willingness to conserve native flora.The availability of native seeds in the market is regulated by demand.However, to promote their use in gardening and its commercialization, it is necessary to establish incentives through the public and private sector, regulations, research, and outreach projects that increase the value of native flora, particularly locally adapted species, in a climate change scenario.Consequently, we encourage the propagation of native flora to increase its availability in the local market and the exchange of its seeds among gardeners, gardening associations and landscape designers.

Figure 1 .
Figure 1.Number of ornamental species seeds sold in the Chilean market by biogeographic origin.Chile is in white color for comparison purposes.In parentheses, the proportion of the total sold seeds.

Figure 2 .
Figure 2. Proportion of different taxa of ornamental species sold as seeds: a) In the Chilean local market and b)native Chilean species sold in the international market.

Table 2 .
Species available in current Chilean seed market for gardens.

Table 3 .
Continuation BIOTIC HOMOGENIZATION IN THE AVAILABILITY OF ORNAMENTAL SEEDS OF THE NATIVE FLORA IN CHILE 186 V. 29, N o .2, 2023 p. 181-199

Table 4 .
Rodríguez et al., (2018)mism per taxonomic family of the Chilean flora and its representation in internationally seeds market.Data of native flora fromRodríguez et al., (2018).

Table 5 .
International companies that commercialized seeds of native species from Seed search catalogue, 5 th (2002) and 8 th (2012) editions.