Orchidaceae is one of the most species-rich families (Plants of the World Online, 2023), yet an estimated 4,342 orchid species are threatened with extinction (Zizka et al., Reference Zizka, Silvestro, Vitt and Knight2021). This estimate only includes species for which the taxonomy is clear and for which basic knowledge regarding geographical location, habitat requirements and/or population size exists (Luer, Reference Luer1996; Kelloff & Kass, Reference Kelloff and Kass2018; Parra et al., Reference Parra-Sanchez, Pérez-Escobar and Edwards2023). For many orchid species such knowledge is lacking, and therefore there is inadequate information for appropriate conservation actions.

Porroglossum parsonsii Luer is one such species for which there is no geographical or ecological information. It is one of the 51 known species in the genus (Karremans et al., Reference Karremans, Moreno, Gil-Amaya, Gutiérrez Morales, Espinosa and Mesa2023), which has its greatest diversity in Ecuador (Baquero et al., Reference Baquero, Minda and Yeager2020) and Colombia (Ortiz-Valdivieso & Uribe-Velez, Reference Ortiz-Valdivieso and Uribe-Velez2007). Despite being traded on the global market, the only recognized collection of P. parsonsii is the holotype in herbarium MO, which was exported from Colombia without any traceable documentation, as suggested in the protologue ‘without collection data, obtained from a Colombian collector, in 2004, flowered in cultivation …, in California’ (C. Luer 20985, MO).

During a large-scale orchid survey (January 2019–December 2021) we found natural populations of P. parsonsii for the first time (voucher E.Parra-Sanchez 1240, herbarium VALLE, Universidad Nacional de Colombia, Palmira; Plate 1). We surveyed 341 randomly located 10 × 30 m plots in Andean forests, paramo habitats and pasturelands in the Eastern Cordillera of the Colombian Andes. Our survey covered c. 270 km from north to south over 1,130–3,700 m elevation (Fig. 1; for additional details see Parra-Sanchez et al., Reference Parra-Sanchez, Pérez-Escobar and Edwards2023). In each plot we recorded adult orchid individuals in the understorey (up to 2 m aboveground). Surveys, by EP-S, required 2–5 h per plot. Around each plot we quantified forest cover in 12 buffer zones to estimate the potential available habitat for species (100, 200, 300, 500, 800, 1,000, 1,200, 1,500, 1,800, 2,000, 2,200 and 2,400 m; Fahrig, Reference Fahrig2013; Hansen et al., Reference Hansen, Potapov, Moore, Hancher, Turubanova and Tyukavina2013). We used landscapemetrics (Hesselbarth et al., Reference Hesselbarth, Sciaini, With, Wiegand and Nowosad2019) in R 4.1.3 (R Core Team, 2022) to quantify the forest cover in each buffer based on the 30 m resolution global change forest map from 2018 (Hansen et al., Reference Hansen, Potapov, Moore, Hancher, Turubanova and Tyukavina2013).

Fig. 1 Locations of the 341 survey sites along the Eastern Cordillera in the Colombian Andes (white circles) and the two locations where we found Porroglossum parsonsii (black triangles): (a) Santuario de Fauna y Flora de Iguaque, and (b) Arcabuco. The radii in (a) and (b) indicate the buffers used to calculate per cent forest cover around the survey plot (100, 200, 300, 500, 800, 1,000, 1200, 1,500, 1,800, 2,000, 2,200 and 2,400 m).

Plate 1 Porroglossum parsonsii Luer showing (a) habit, (b) peduncle and flower, (c) dissected sepals, petals and lip, spread, (d) ovary, column and lip, lateral view, (e) detail of the lip, lateral view, and (f) detailed pollinia and anther cap. Photographs: JSM and SV-U from in situ plants. Voucher preserved as E.Parra-Sanchez 1240 at herbarium VALLE.

We found P. parsonsii in two of the 341 plots, separated by 17.6 km, with forest cover of 77.2–82.0% in the protected area Santuario de Fauna y Flora de Iguaque at 3,140 m, and 71.4–86.2% cover in Arcabuco at 2,580 m in a forest patch c. 30 m from a dirt road and near pasturelands (Fig. 1). The species grows as an epiphytic plant on mature trees (tree density 0.20–0.29 trees/m²), with low local population sizes (5–17 adult individuals per plot). We have not extrapolated this local density to a larger area as P. parsonsii probably grows in non-uniform, small and widely spaced clusters, as suggested by our surveys and by surveys elsewhere of other orchid species in related genera (Peláez et al., Reference Peláez, Buitrago-Delgado and Meyer2009; Baquero & Meyer, Reference Baquero and Meyer2014; Kindlmann et al., Reference Kindlmann, Meléndez-Ackerman and Tremblay2014).

Our extensive survey suggests P. parsonsii has a limited geographical range, a non-uniform occurrence within the same habitat or across habitats in the region and a small population size. Porroglossum parsonsii should probably be categorized as Critically Endangered on the IUCN Red List as it has a restricted distribution (area of occurrence < 500 km², criterion B; IUCN, 2012), with a small number of individuals (< 50, criterion D), and there is an inferred past population reduction based on the reduction of habitat in the landscape, although the landscape still has high structural connectivity and habitat availability. A full Red List assessment will require additional information on population dynamics, and further surveys in the surrounding areas are required to identify whether there are any additional populations.

Porroglossum parsonsii is traded at a price of USD 18–20 per plant (based on the websites Equaflor-A, 2019, and Ecuagenera, 2023), with the origins of these traded plants being unknown. We speculate that individuals were taken from the wild (either from the localities we report here or from others nearby) and grown in nurseries, as mentioned in the holotype. Illegal collection of native species is one of the greatest threats to orchid diversity (Wraith & Pickering, Reference Wraith and Pickering2018), although the full impact of this on abundance in the wild is unknown (Hinsley et al., Reference Hinsley, de Boer, Fay, Gale, Gardiner and Gunasekara2018; Morton et al., Reference Morton, Scheffers, Haugaasen and Edwards2021). However, frequent illegal collections from orchid populations have led to local reductions in the number of adult individuals and could affect phenological cycles (Emeterio-Lara et al., Reference Emeterio-Lara, García-Franco, Hernández-Apolinar, Toledo-Hernández, Valencia-Díaz and Flores-Palacios2021).

We recommend that Santuario de Fauna y Flora de Iguaque integrates P. parsonsii into its strategic plan for the conservation of threatened species (Díaz, Reference Díaz2020). This would promote monitoring and conservation of the wild population. In addition, we recommend protection of the trail where the population is located, minimization of the effects of tourism and mechanical damage, further surveys across Santuario de Fauna y Flora de Iguaque to detect any other occurrences of the species, and inclusion of adult plants in the protected area's nursery.