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*Background and Aims Evaluation of population projection matrices (PPMs) that are focused on asymptotically based properties of populations is a commonly used approach to evaluate projected dynamics of managed populations. Recently, a set of tools for evaluating the properties of transient dynamics has been expanded to evaluate PPMs and to consider the dynamics of populations prior to attaining the stable-stage distribution, a state that may never be achieved in disturbed or otherwise ephemeral habitats or persistently small populations. This study re-evaluates data for a tropical orchid and examines the value of including such analyses in an integrative approach. *Methods Six small populations of Lepanthes rubripetala were used as a model system and the R software package popdemo was used to produce estimates of the indices for the asymptotic growth rate (lambda), sensitivities, reactivity, first-time step attenuation, maximum amplification, maximum attenuation, maximal inertia and maximal attenuation. The response in lambda to perturbations of demographic parameters using transfer functions and multiple perturbations on growth, stasis and fecundity were also determined. The results were compared with previously published asymptotic indices. *Key Results It was found that combining asymptotic and transient dynamics expands the understanding of possible population changes. Comparison of the predicted density from reactivity and first-time step attenuation with the observed change in population size in two orchid populations showed that the observed density was within the predicted range. However, transfer function analysis suggests that the traditional approach of measuring perturbation of growth rates and persistence (inertia) may be misleading and is likely to result in erroneous management decisions. *Conclusions Based on the results, an integrative approach is recommended using traditional PPMs (asymptotic processes) with an evaluation of the diversity of dynamics that may arise when populations are not at a stable-stage distribution (transient processes). This method is preferable for designing rapid and efficient interventions after disturbances, and for developing strategies to establish new populations. [ABSTRACT FROM AUTHOR]

The metapopulation concept is widely established in population biology. It predicts that the likelihood of colonization of an empty patch is positively correlated with its connectivity, because colonizers from occupied patches will be more likely to reach an empty patch if they are closer to it. Another prediction is that the likelihood of extinction of an occupied patch will be negatively correlated with its connectivity to other patches, as the occupied patch can be 'reinforced' by immigrants from patches that are close by. We tested these predictions using an extensive data set for an epiphytic orchid, Lepanthes rupestris from Puerto Rico. Our data did not support the first prediction, but we found that the likelihood of extinction is negatively correlated with patch connectivity. We hypothesize that this might be because most orchid seeds are wind dispersed and seeds that do not fall immediately below the mother plant are uniformly distributed after a steep leptokurtic distribution. We predict that taxa with similar seed and gene flow characteristics should show similar patterns in the association between colonization/extinction rates and patch connectivity. © 2014 The Linnean Society of London, Botanical Journal of the Linnean Society, 2014, 175, 598-606. [ABSTRACT FROM AUTHOR]

Aim The aim of this analysis was to identify strategies that will maximize efficiency and effectiveness in conservation planning. As many orchids are threatened with extinction for various reasons, our primary objective was to combine hotspots analyses with stochastic extinction modelling to highlight possible conservation priorities for Lepanthes spp. (Orchidaceae) based on patterns of richness, rarity and threat. Our subsequent objective was to identify potential conservation surrogates and variables that are the best predictors of extinction probabilities. The ultimate goal was to determine which factors should be emphasized in conservation planning to prevent species extinctions. Location Latin America; the Caribbean. Methods We used herbarium records and Arc GIS to map the distribution of Lepanthes spp. and to identify hotspots of richness and rarity. We forecasted extinction patterns with Koopowitz's stochastic extinction model and calculated extinction probabilities in each country. We used a randomForest regression model in R to assess the importance of richness, rarity and threat for explaining extinction probabilities. Results Hotspots of Lepanthes richness and rarity occurred in north-western South America and southern Central America and largely overlapped with each other. The highest extinction probabilities occurred in northern Central America, Haiti and Ecuador, and generally, hotspots of richness and rarity did not correspond with patterns of threat. Habitat loss was the most important variable for explaining extinction probabilities, followed by measures of rarity. Main conclusions Conservation efforts will be most efficient in richness and rarity hotspots, and because they overlap, rarity hotspots could act as surrogates for protecting overall Lepanthes diversity. Hotspots rarely occurred in the most threatened areas, and therefore, conservation efforts are more urgent in non-hotspot areas. Conservation efforts will be most effective if they combine ex situ strategies in locations with high habitat conversion rates with reservation strategies in rarity and richness hotspots, particularly where they overlap. [ABSTRACT FROM AUTHOR]

* Premise of the study: Biotic changes are an inevitable consequence of climate change. Epiphytes may be more susceptible to changes in climate variation, but data regarding responses to climate variability under field conditions are limited. We evaluated whether the abundance of demographic stages in the epiphytic orchid Lepanthes rupestris at the Luquillo Experimental Forest in Puerto Rico was associated with short-term changes in climate variation over an 8-yr period. * Methods: We used cross-correlation analyses to evaluate associations between the abundance of seedlings, juveniles, adults, and fruits per subpopulation, population growth, colonization and extinction rates in L. rupestris with variables related to precipitation and temperature, with and without lag-responses. * Key results: We detected significant negative correlations between the average number of seedlings and the number of dry days, between the average number of fruits and minimum average temperature with a 6-mo response lag, and between the average number of adults and the maximum temperature with a 1-yr response lag. Neither population growth rate nor probability of colonization and extinction were directly related to climatic variation between 2000 and 2007. * Conclusions: Associations between climatic variables and demographic stages could have negative implications for this orchid within the context of expected drying trends in the Caribbean. Results argue for the establishment of long-term monitoring studies of orchid populations, because only long-term studies would provide the appropriate temporal scale to detect and predict climate change effects and adaptive management of orchid populations. [ABSTRACT FROM AUTHOR]

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Summary 1 Mycorrhizal associations of tropical, epiphytic orchids have been studied in vitro , but the importance of the relationship has not been demonstrated in the field. We investigated the effect of fungicide treatment on seedlings and juveniles of the lithophytic orchid Lepanthes rupestris . As mycorrhizas, endophytes and pathogens coexist in orchids, fungicide treatment might have either a positive or negative effect on growth and survival of plants. 2 The experimental design included benomyl-treated, propiconazole-treated, and control plots. Each treatment consisted of about 140 2 × 2 cm plots divided among eight rocks, with one seedling or juvenile (occasionally two) per plot. Fungicides were applied every 2 weeks and plants were censused and measured every 3 months for 8–9 months. 3 Propiconazole-treated plants had higher mortality, significantly fewer leaves, significantly fewer fungal colonies in their roots, and significantly fewer degraded pelotons than did control plants. Benomyl-treated plants had significantly lower mortality than controls and significantly fewer fungi in leaves than control plants, and did not differ in number of degraded pelotons. There was little or no recruitment in any treatment. 4 Few potentially mycorrhizal fungi were isolated. Guignardia , Colletotrichum and Xylaria , which are generally endophytes, pathogens and/or saprotrophs, were more common. There was evidence of antagonism between Colletotrichum and Xylaria and between Colletotrichum and Guignardia . 5 Results suggest that fungi have both positive and negative effects on growth and survival of L. rupestris plants. However, conclusions about the importance of mycorrhizas are complicated by the simultaneous occurrence of a range of orchid–fungus interactions. [ABSTRACT FROM AUTHOR]

Variance in floral morphology among populations was investigated in three species of Lepanthes (Orchidaceae) from Puerto Rico. Populations that share a common gene pool and similar environment are expected to share similar phenotypes, so that populations that are physically close should be more similar to each other than populations that are separated by large distances as gene flow is usually leptokurtic. Univariate and multivariate analyses of floral characteristics were compared using MANOVA and Linear Discriminant Function Analysis. Most groups of individuals (populations) differed significantly when analyzed by univariate or multivariate methods. Floral characteristics of populations separated by only few meters were often significantly different. No correlation between amount of morphological difference (square Mahalanobis distances) and inferred gene flow (physical distances) was present in any of three species studied. Other research has shown that genetic population sub-structuring is high and effective population size is extremely small in all three species of orchids. It is thus argued that the large amount of morphological differences among populations are likely a result of genetic drift or phenotypic plasticity, and are unlikely to be the result of natural selection at the micro habitat level. [ABSTRACT FROM AUTHOR]

Little is known about non-mycorrhizal endophytic fungi in tropical orchids; still less is known about how endophytes vary within and between individual orchid plants. Fungal endophytes were isolated from roots and leaves of epiphytic and lithophytic orchids in the genus Lepanthes; seven species, from rainforests in Puerto Rico, were sampled. The endophytes observed most frequently were Xylaria species and Rhizoctinia -like fungi, found [ABSTRACT FROM AUTHOR]

Focuses on a study which examined the fruit production of the Puerto Rican endemic orchid Lepanthes woodburyana Stimson through self- and cross-pollination. Materials and methods; Difference between self- and cross-pollination.