Transient Population Dynamics of Two Epiphytic Orchid Species after Hurricane Ivan: Implications for Management

Abstract

Populations of epiphytic orchids in disturbance‐prone environments rarely reach stable‐stage equilibrium. We characterized the post‐disturbance, transient dynamics of two epiphytic orchids, Broughtonia cubensis, and the leafless Dendrophylax lindenii, comparing the following indices: reactivity/first‐time attenuation, maximal amplification/attenuation, and amplified/attenuated inertia. We also assessed the effects of reintroducing only seeds or only adults, by examining the elasticity of the inertia on the vital rates. For 2006–2010, the stochastic growth rate of D. lindenii was λs = 0.94, or a 6 percent decrease per annum. First‐time step attenuation indicates that in 1 year, the population could decrease by an additional 16 percent, and in the worst‐case scenario could decrease by almost half, relative to the stable‐stage distribution, in 10 years. Broughtonia cubensis had a λs = 1.03; reactivity and first‐time step attenuation indicates that in 1 year, the population should not change by more than 14 percent of the estimated stable‐stage distribution. However, the worst‐case scenario projected a reduction of 40 percent relative to the stable‐stage distribution within 8 years. A comparison of reintroduction strategies assessed by elasticity of the population momentum showed that adults performed better when relocated to new habitats.

Variation across river channels in demographic dynamics of a riparian herb with threatened status: management and conservation implications

“…Benth. ex Rolfe (Raventós et al., , ), and the threatened cactus species Mammillaria gaumeri (Britton & Rose) Orcutt (Ferrer‐Cervantes et al., ). All these species and our target species were similar in terms of elasticity analyses, where the survival and growth of larger plants contributed most to the changes in the population growth rate.…”

“…Thus, management actions to reduce the time required to reach a desirable size should be prioritized. The use of larger plants (i.e., adult plants) seems to provide a better management strategy for some epiphyte orchids (Tremblay, ; Raventós et al., ); thus, one strategy to accomplish this goal is the reintroduction of vegetative material. The results of pilot studies suggest that 15‐cm plant cuttings artificially attached in the field could reach a reproductive stage in 2 years (M. Pérez et al., unpublished manuscript).…”

“…The COMPADRE data base lists 468 studies that incorporate 598 plant (and algal), species with most of the demographic effort concentrated in North America, Europe, Australia, and Brazil, and fewer studies in areas considered as biodiversity hot spots (Salguero‐Gómez et al., ). For example, in the Caribbean region, an important biodiversity hotspot (Myers et al., ; Olson et al., ), there are only 11 plant species that do include demographic models (eight in the Orchidiaceae family; Calvo, ; Tremblay, ; Tremblay and Hutchings, ; Schödelbauerová et al., ; Olaya‐Arenas et al., ; Wiegand et al., ; Crain, ; Tremblay and McCarthy, ; Raventós et al, , ; Tremblay et al., ; Falcón et al., ), one in the Cactaceae (Rojas‐Sandoval and Meléndez‐Ackerman, ), one in the Cycadaceae (Negrón‐Ortiz et al., ), and another in the Melastomataceae (Pascarella et al., ). Of those species, only three have been assigned risk categories.…”

Seasick: Why Value Ecosystems Severely Threatened by Sea-Level Rise?

“…1d ; Box 1 ). For example, remnant populations of unique orchid species face increased habitat deterioration from SLR and hurricanes (Raventós et al 2015 ). As sea levels rise, ecosystems will experience shifts in distribution and composition (Geselbracht et al 2011 ), including transitions from coastal forests to saltmarsh and from inland forests to tidal flats.…”

Sheltered from the storm? Population viability analysis of a rare endemic under periodic catastrophe regimes

“…Despite periodic hurricanes, the orchid flora of the Caribbean is particularly diverse (Ackerman, , ), consisting of a variety of rare and endemic species that occur in dynamic habitats (Boose, Serrano, & Foster, ; Raventós, González, Mújica, & Doak, ; Rodríguez‐Robles, Ackerman, & Meléndez, ; Tremblay, ). Although limited in number, some studies from the Caribbean show that hurricanes can have adverse effects on orchid populations (Mújica, Raventós, González, & Bonet, ; Raventós, González, Mújica, & Bonet, ; Raventós, González, Mújica, & Doak, ; Tremblay, ; Wiegand, Raventós, Mújica, González, & Bonet, ) whereas others suggest that certain species can benefit from hurricane disturbances to varying degrees due to reduced competition and increased accessibility to resources for example (Ackerman & Moya, ; Pascarella, ; Pascarella & Horvitz, ; Wiegand et al, ). Accordingly, it is necessary to determine how hurricane disturbances might affect population growth and persistence of rare orchid species in the Caribbean to evaluate their conservation status.…”