Ecological factors affecting the fitness of the threatened orchid Anacamptis robusta (Orchidaceae): Habitat disturbance, interactions with a co‐flowering rewarding orchid and hybridization events

Abstract

The food-deceptive species Anacamptis robusta is threatened in the Balearic Islands, and its habitat has recently been transformed through human disturbance. This study investigated how human disturbance affects the reproductive output of A. robusta and how its fitness is affected by competition with rewarding relatives, fungal infections and hybridization processes. • To evaluate the impact of habitat loss on plant fitness, data on reproductive measures were obtained in two well-conserved subpopulations and the unique disturbed subpopulation. Photo-trapping cameras were installed to determine the floral visitation rate. All flowering individuals in 2019 were georeferenced using differential GPS to examine the influence of geospatial patterns on the reproductive success of A. robusta. In addition, hand-pollination treatments were performed to evaluate the hybridization between A. coriophora and A. robusta and the origin of A. 9 albuferensis. • The human-disturbed subpopulation of A. robusta had a lower fruit set success than the subpopulations in well-conserved areas. The presence of A. coriophora is negatively affecting the reproductive output of A. robusta. Moreover, A. robusta can only act as the pollen donor during hybridization. • The complexity of the ecological system, which is enhanced by the strong pollinator dependence of the threatened species, must be considered when making conservation decisions. Although human disturbance directly affects plant population stability, other ecological issues must be considered, such as pollinator interaction, interspecific competition for pollinators, fungal infection and hybridization events.

Phenotype–fitness relationships and pollen‐transfer efficiency of five orchid species with different pollination strategies

“…On the contrary, in S. parviflora , flower number was negatively related to fruit set. The negative correlations found in this study may be attributable to resource limitation, as reported by Capó et al (2021) and Jersáková et al (2006). However, additional research is necessary to validate this finding.…”

“…Data are available from the Zenodo Digital Repository https://doi.org/10.5281/zenodo.7826601 (Capó et al, 2023).…”

“…The reproductive biology of deceptive orchids in relation to female fitness has been extensively studied (Tremblay et al, 2005; Rodríguez‐Otero et al, 2023 [in this issue]); fewer studies have included and noted the importance of male fitness (Nilsson, 1992; Tremblay and Ackerman, 2007; De Jager and Peakall, 2019; Borràs and Cursach, 2020; Capó et al, 2020). Interestingly, several plant phenotypic traits influence both male and female fitness in deceptive species, such as plant height, inflorescence size, and flower number (O'Connell and Johnston, 1998; Borràs and Cursach, 2020; Capó et al, 2021), among others.…”

Preventing inbreeding depression in Anacamptis coriophora (Orchidaceae) as a model of food-rewarding orchid

“…Moreover, plant morphology and population structure are also likely to be important. Parameters such as plant height, inflorescence size, flower number, spur length, population size, flowering time and canopy density have been demonstrated to affect or influence fitness (Scopece et al 2017;Capo ´et al 2020a). Thus, monitoring of the within-species variation in individual fitness is important to obtain a more realistic overview of the reproductive biology of these species.…”

Pollination mechanism inSerapiaswith no pollinaria reconfiguration

“…Low mean reproductive success rates have been reported for sexually deceptive orchids ( Vandewoestijne et al 2009 ; Borràs and Cursach 2021 ), food-deceptive orchids ( Dormont et al . 2010 ; Pellegrino et al 2010 ; Claessens and Kleynen 2011 ; Capó et al 2021 ) or colour dimorphic orchids ( Pellegrino et al 2008 ; Sonne and Hauser 2014 ; Jersáková et al 2015 ). High fruit set values (above 50 up to 80 %) have been reported in natural populations of rewarding orchids ( Meekers and Honnay 2011 ; Joffard et al 2020 ; Zhang and Gao 2021 ).…”