A checklist of Orchidaceae from Caquetá, Colombia is presented here. We recorded 98 genera and 418 species, exceeding a previous inventory by 276 species. The checklist is conservative in the number of genera and species by including only taxa that were fully and reliably identified and that are either linked to a corresponding herbarium voucher, a living collection specimen or a photo taken in the field and published in iNaturalist by one of the authors or a collaborator. The documented species diversity in the region could dramatically increase in the next few years with additional collecting efforts in the eastern slopes of the Andes nested in Caquetá. About 9% (418/4600) of all Orchidaceae species recorded for Colombia are reported for this area, showing the important contribution to orchid diversity of Andean-Amazonian foothills of Caquetá.

Alpha diversity, Amazon, Andes, floristic studies, foothills, orchids

Orchidaceae are one of the most diverse and widely distributed flowering plant families including 25,000–27,000 species and 880 genera (Chase et al. 2015). Colombia has the largest diversity of orchid species in the American tropics (Pérez-Escobar et al. 2022a), hosting ~ 4,600 species that represent ~18% of the known species diversity in the family. The highest level of species richness arises in the northern Andes region of the country (Pérez-Escobar et al. 2022a), where a large number of endemic species occur, accounting for 36.8% of the total species reported for Colombia. With new orchid novelties published annually (Ortiz Valdivieso et al. 2009; Hágsater et al. 2013; Pérez-Escobar et al. 2021, 2022b; Vieira-Uribe and Moreno 2022), Colombia is a hotspot for biodiversity conservation (Betancur et al. 2015).

Caquetá, one of Colombia’s 32 Departments, is a largely unexplored region with an extraordinary ecosystem diversity, geographically presenting a variety of landscapes, topographic forms and different types of associated vegetation and water sources, including the Amazon plains, valleys, hills, foothills and mountain ranges (Fig. 1). The Department contains four national natural parks, covers part of the Chiribiquete World Heritage Park and 35 recognised civil society reserves (RUNAP 2022, webpage checked June 2023). Caquetá is placed in the eastern slopes of the Andean foothills, a confluence zone of mountainous and lowland Amazonian landscapes with different communities’ composition. The Andean foothills of Caquetá range between 200 and 1000 m a.s.l.

Figure 1. 

Representative landscapes from Caquetá, Colombia. A general view of the Andean Piedmont in the Municipality of Florencia B Hills and rivers coming down from the eastern slopes of the Andes and flowing into the Amazonian Forest in the Municipality of Belen de los Andaquíes, the Pescado River C Hilly slopes from the Andean Piedmont transitioning to the Amazon Forest in the Municipality of Belen de los Andaquíes D General view of Amazonia Forest from a hilly slope of the eastern Andes, in the Municipality of Paujíl E, F Amazonian waterlogged Forest at La Laguna de Peregrinos, Municipality of Solano.

The Colombian Eastern Andean Mountain range transitions along an environmental gradient from foothills to either the Guyana Shield (Meta and Caquetá), the Amazon Basin (Caquetá, Putumayo and Amazonas) or the Orinoco Basin (Arauca, Casanare and Meta) (Hoorn et al. 2010). These ecotones are hyperdiverse because of the evolutionary, biogeographical and ecological processes that operate in a rich array of landscapes (Ruiz et al. 2007; Instituto Geográfico Agustín Codazzi 2010). It is perhaps in the confluence of lowland and mountainous landscapes where the greatest wealth of plant species diversity and endemism occurs in the country (Ruiz et al. 2007; Pérez-Escobar et al. 2022a), but the limited existing orchid inventories underestimate the region’s species diversity.

Although Orchidaceae are diverse within Caquetá, few checklists and taxonomic studies focusing on this group are available. For example, the Catalogue of Plants and Lichens of Colombia (Bernal et al. 2016), reported a total of 104 orchid species, whereas “The National Orchid Conservation Plan” presented a count of 142 species (Betancur et al. 2015). Currently, Caquetá is severely affected by deforestation driven by anthropogenic transformations of the natural ecosystems (Jaramillo-Castelblanco 2016; IDEAM 2020). Biological diversity inventories of the Andean-Amazonian Region are, thus, crucial to provide information for habitat conservation strategies in the region.

In this study, we generated a detailed species list of Orchidaceae for the Department of Caquetá, one of the most unexplored areas in Colombia, due to, amongst other factors, difficulties such as security risks and lack of easy access routes to some of its regions and municipalities. This is a collective work developed by more than twelve Colombian botanists during 2019–2023, under the umbrella project “Orquídeas para la Paz” (Orchids for Peace). This programme aims to explore, reproduce and support orchid species recovery, while developing sustainable strategies for business, based on horticulture for vulnerable communities around Colombia. Data obtained here come from living collections, photographs taken from field and an extensive review of herbarium collections around the world.

A total number of 228 fertile specimens were collected in the field (collections made by Arias T., Chaux-Varela J., Perdomo O., Trujillo E. and Correa M.), 692 herbarium specimens were reviewed in different herbaria, 100 photographs and two living collections accessed for specimen identifications. The most abundant species in the field were Epidendrum nocturnum Jacq., E. lacustre Lindl., Maxillaria discolor (G. Lodd. ex Lindl.) Rchb. f. and Scaphyglottis stellata Lodd. ex Lindl. Some of the rarest ones only observed in the field once were Cyrtochilum caquetanum P. Ortiz, L. E. Álvarez & A. J. Carrillo, Masdevallia ensata Rchb. f. and Paphinia cristata (Lindl.) Lindl. In “Orquídeas para la Paz” expeditions, 98 species (collections made by Arias T. and Chaux-Varela J.) representing 29 genera were collected. Living individuals that were not flowering in the field were brought to El Manantial (300 m a.s.l.) and El Caraño (950 m a.s.l.) both located in the Municipality of Florencia. Herbaria collections are actively being made once orchids start flowering. A total of 55 species are available at El Manantial and 60 at El Caraño.

We report 418 species belonging to 98 genera represented in 744 herbarium collections including duplicates. Eighty-two species are new reports for Caquetá since they have not been vouchered until this study (Table 1, collections exclusively made by one of the authors of this paper). The most species-rich genera were Epidendrum L. (68 spp.), Maxillaria Ruiz & Pav. (59 spp.), Pleurothallis R.Br. (16 spp.), Elleanthus C. Presl (14 spp.), Sobralia Ruiz & Pav. (14 spp.) (Table 1, Figs 2–5). Most genera found in Caquetá (75) have one to three species (Fig. 5). We found two introduced species around urban areas of Florencia, Arundina graminifolia (D. Don) Hochr. and Dendrobium nobile Lindl.; these were not included in the species list.

Figure 2. 

Representative Orchidaceae species from Caquetá, Colombia. A Acianthera casapensis B Acianthera ciliata C Laelia rosea D Catasetum tuberculatum E Cattleya violacea F Trichocentrum nudum G Cyrtochilum porrigens H Epidendrum fimbriatum I Dimerandra emarginata J Epidendrum coronatum K Epidendrum difforme.

Figure 3. 

Representative Orchidaceae species from Caquetá, Colombia. A Galeandra macroplecta B Maxillaria aureoglobula C Maxillaria egertoniana D Maxillaria equitans E Maxillaria parkeri F Maxillaria parviflora G Notylia barkeri H Oncidium alexandrae I Octomeria grandiflora J Prosthechea chimborazoensis K Stanhopea candida L Sobralia macrophylla.

Eighty-one species are included as “tentative” because they have been accurately identified, but lack a herbarium voucher. Fifty-three out of these 81 were included as potentially distributed in the Caquetá because records produced by the authors and collaborators in the field through photographs were not documented with herbarium vouchers. Such photographic records were submitted to iNaturalist (see https://www.inaturalist.org/projects/orquideas-del-caqueta). Twenty-seven species including 15 in El Manantial and 12 in El Caraño, are part of our living collections. They were collected fertile in the field and identified, but have not been photographed or documented with herbarium vouchers to date.

For the Municipality of Florencia, 192 species were recorded, followed by Solano with 108 and Belén de los Andaquíes with 77 (Fig. 4). Five municipalities including Albania, Morelia, Valparaíso, Milán and La Montañita have three or less records and there are no orchid botanical collections for Curillo and Solita (Table 1). Fourteen species are endemic to Colombia and from those, 11 have new herbarium vouchers made in this project. Twenty nine are new reports for Colombia and 15 of those have new herbarium vouchers as a result of this project (Table 1). Masdevallia virgo-cuencae Luer & Andreetta (VU), Miltoniopsis phalaenopsis (Linden & Rchb. f.) Garay & Dunst. (VU) and Oncidium alexandrae (Bateman) M. W. Chase & N. H. Williams (EN) were included in the Red List of Colombian orchid species (Calderón-Sáenz 2007).

Figure 4. 

Distribution of orchid species number in Caquetá municipalities. A Orchid species distribution by municipality and a heatmap of species richness found in each of the municipalities B Number of orchid species found in each municipality and their geographic position (Andean Piedmont or Amazonian Basin).

Most collections made in Caquetá have been deposited at HUAZ, which currently holds 210 orchid specimens, while COAH holds 207 orchid specimens and COL 109 orchid specimens. Seven international herbaria had between 1–12 collections from Caquetá (Table 1).

A total of 276 new species records of Orchidaceae were added to the previous orchid report of Betancur et al. (2015), who cited 142 species. The great diversity of Orchidaceae species in Caquetá might be explained by spatial heterogeneity and phytophysiognomies in this region (Etter et al. 2006). The significant diversity of Epidendrum (68/1000) and Maxillaria (59/570) was expected because these are some of largest Neotropical Orchidaceae genera with regards to species number (Fig. 5, Suppl. material 1: table S1). The four most species-rich genera account for 40% of the total species, but they represent 4.12% of the total genera. Forty-three genera included only one species for the region, which corresponds to 19% of the total species and 42% of the total genera. Species in genera, such Encyclia Hook. and Stelis Sw., were challenging to identify and additional taxonomic work is required. One widely distributed and unpublished hybrid Epidendrum × communis Hágsater Ined. was added to the list after specialist advice (Hágsater, pers. comm.)

Figure 5. 

Number of orchid species in most abundant genera of Caquetá, Colombia A number of species in the most species rich genera of Caquetá B pie chart showing the proportion of species in genera with 9 to 70 species.

During the construction of this list, we left out collections made by Werner Hopp (Schlechter 1924) since they were collected in Putumayo in 1921 and 1922 when Putumayo was part of the Caquetá intendancy. In 1991, Putumayo was politically recognised as a Department and, as such, it is no longer part of Caquetá. Additionally, some species collected by Hopp were deposited in the Berlin Herbarium (B) and destroyed during Second World War (Suppl. material 1. table S2).

Most orchid species documented in Caquetá are found in the Florencia Municipality (192 spp.). This could be explained by the convenience of collecting around cities and the wide altitudinal gradient in this municipality. We present collections numbers by municipality because conservation strategies might differ between political boundaries in Colombia. Regional Autonomous Corporations (CAR) are the main environmental authority. They are responsible for implementing policies and plans from the Ministry of Environment and are granted administrative and financial autonomy. Entities responsible for the formulation of such conservation strategies might benefit more from having such information presented following Departmental divisions. By depositing 140 herbarium specimens at HUAZ (duplicates will be sent to other herbaria) in the framework of this study, we substantially increased its orchid collection to 210 species, positioning HUAZ as the first local herbarium with more herbarium collections from Caquetá than any other herbaria (Fig. 6, Suppl. material 1: table S1).

Figure 6. 

Number of orchid species in the Colombian national herbaria and international herbaria. Instituto Amazónico de Investigaciones Científicas – SINCHI (COAH), Herbario Nacional Colombiano (COL), Herbario de la Universidad del Cauca (CAUP), Herbario de la Universidad del Valle (CUCV), Herbario de la Universidad de Caldas (FAUC), Herbario Federico Medem-Bogotá (FMB), Herbario de la Pontificia Universidad Javeriana (HPUJ), Herbario de la Universidad de Antioquia (HUA), Herbario Enrique Forero (HUAZ) de la Universidad de la Amazonia, Jardín Botánico José Celestino Mutis de Bogotá (JBB), Universidad de los Llanos (LLANOS>), Universidad de Nariño (PSO), Universidad Surcolombiana (SURCO), Herbario Forestal de la Universidad Distrital Francisco José de Caldas (UDBC), and Universidad Pedagógica y Tecnológica de Colombia (UPTC).Harvard University Oak Ames Herbarium (AMES), Herbario del Instituto Chinoin (AMO), Berlin (B), Royal Botanic Gardens Kew Herbarium (KEW), University of California, Los Angeles Herbarium (LA), the Real Jardín Botánico de Madrid (MA), Naturalis Biodiversity Center (NL) - Botany (Herbarium Utrech), New York Botanical Garden (NY), the Herbier Museum Paris of the Museum National D´Histoire Naturelle (P), Marie Selby Botanical Gardens (SEL), TROPICOS database (access 2022) of the Missouri Botanical Garden (MO), Gdansk University (UGDA), University of Florida Herbarium (USF), W-Reichenbach (Vienna) and University of Wisconsin Herbarium (WIS).

Five of the municipalities of Caquetá, representing ~ 20% of the total geographical area of the Department, had zero to three herbarium collections or species reported (Fig. 4). The areas in the north-eastern part of the eastern Andean Mountain range still need extensive exploration. These areas include the National Natural Park Cordillera de Los Picachos, where landmines were planted by rebel groups during the long armed conflict that lasted for decades and these have not been removed to date. Orchid diversity could significantly increase with the development of intensive exploration in these mountainous ecosystems and a thorough exploration of the Amazonian Forest canopy. For instance, Departments like Antioquia and Huila have been catalogued as having the largest orchid diversity (Betancur et al. 2015); however, these areas of Colombia have not been extensively explored for decades.

During our expeditions, two species Cattleya violacea (Kunth) Lindl. and Trichocentrum lanceanum (Lindl.) M. W. Chase & N. H. Williams have been found only in La Laguna del Chaira in the Cartagena del Chaira Municipality. We doubt these species have a natural distribution there. Rather, we suspect they were introduced during the massive effort to bring orchids to La Laguna del Chaira during the 1980s, during which “uninformed” reintroductions of non-native species could have taken place.

This checklist places Caquetá as the eighth Department in Colombia in terms of genera diversity (98 genera) from its original position in the National Plan of Orchid Conservation (15^th place, 62 genera). As for the ranking in species number for Colombia, Caquetá goes from position 17^th (142 spp.) to position 9^th (418 spp.) (Betancur et al. 2015). Caquetá has many orchid genera (98/258 in Colombia) with few species each, 76% of genera having around 1–3 species. Each of these genera include a unique clade distributed in a relatively small area of Colombia. This could be of particular interest in conservation, prioritising evolutionary history over species diversity (Arponen 2012). Caquetá would be one of the regions of Colombia where there are more different genera represented in clades than in other Colombian regions. This work supplies valuable evidence to promote conservation efforts and politics for habitat preservation of the Colombia Andean Piedmont.

Caquetá has lost approximately 30% of its original area due to human impacts, such as cattle ranching. National parks in Caquetá make up 65% of the protected remnants. In the last 50 years, expansion of the agricultural frontier for the establishment of grazing lands, wood extraction and illegal coca crops have destroyed many ecosystems, greatly impacting all national parks. Florencia, for example, is currently undergoing consistent expansion of farming lands ultimately leading to the decimation of natural ecosystems (IDEAM 2020).

Our floristic study is a needed contribution towards a better understanding of the diversity of Colombian orchids. The checklist provides a set of freely-available data on orchid diversity in Caquetá. Furthermore, our study is a baseline panorama of orchid species diversity in the Department, identifying groups of interest for further taxonomic work, especially those which have not been monographed. Lastly, the information provided could enhance local conservation strategies for endangered floristic elements in the Department by adding to a more complete overview of the high orchid diversity in the region.

We thank Mary Polania Ossa for taking care of the orchid living collections at La Reserva Comunitaria El Manantial in Florencia, Caquetá. We also thank members of different municipalities and regions around Caquetá who guided us, helped us in the field and hosted us in their houses during expeditions for this work. The curators and staff from all herbaria consulted here. Additionally, Eric Hágsater from Herbario AMO; Gerardo Salazar from Universidad Nacional de Mexico (UNAM); Mark Wilson from Colorado College; Adam Karremans and Gustavo Rojas from Lankester Botanical Garden; Stig Dalstrom, Sebastian Vieira, Eugenio Restrepo and Sebastian Moreno for their help in the identification and curation of the specimens. Alvaro Duque from Universidad Nacional sede Medellín provided a list of orchids from Chiribiquete and William Vargas from Corporación Paisajes Rurales provided a list of orchids from field trips he has made around Caquetá.