Pollination Mechanisms are Driving Orchid Distribution in Space

Predictions of species distributions based only on models estimating future climate change are not reliable

Changes in climate and land use are the most often mentioned factors responsible for the current decline in species diversity. To reduce the effect of these factors, we need reliable predictions of future species distributions. This is usually done by utilizing species distribution models (SDMs) based on expected climate. Here we explore the accuracy of such projections: we use orchid (Orchidaceae) recordings and environmental (mainly climatic) data from the years 1901-1950 in SDMs to predict maps of potential species distributions in 1980-2014. This should enable us to compare the predictions of species distributions in 1980-2014, based on records of species distribution in the years 1901-1950, with real data in the 1980-2014 period. We found that the predictions of the SDMs often differ from reality in this experiment. The results clearly indicate that SDM predictions of future species distributions as a reaction to climate change must be treated with caution.

Can global warming be beneficial for Arctic-alpine orchid species? Outcomes from ecological niche modeling for Chamorchis alpina (L.) Rich. (Orchidaceae)

The disjunct Arctic-alpine plants that persist on isolated mountain sites at the limits of their geographical range are particularly sensitive indicators of climate change effects. Here, we investigated a remarkably fragile plant, the smallest orchid in Europe, Chamorchis alpina. The ecological niche modeling (ENM) approach was employed not only to verify the shift in the range of the studied orchid but also to evaluate the future overlap between this plant population and its pollen vectors, Dasytes alpigradus, Formica lemani and Leptothorax acervorum. Our analyses showed that the bioclimatic preferences of the northern (Scandinavian) populations differed from those of the southern populations located in the Alps and Carpathians. Surprisingly, both C. alpina groups will expand their potential ranges under the SSP2-4.5 climate change scenario, and additional suitable niches will become available for the northern group under the SSP3-7.0 scenario. The Scandinavian populations will face significant habitat loss (36 %) in the SSP5-8.5 projection. The southern group will lose suitable niches under both the SSP3-7.0 and SSP5-8.5 scenarios (33 % and 58 %, respectively). For all pollinators of C. alpina, global warming will be favorable, and all three species will expand their potential ranges under all analyzed climate change scenarios. Our research suggests that a "middle of the road" scenario of climate change (SSP2-4.5), which assumes that socioeconomic factors follow historical trends, will not be harmful to the studied orchid or possibly other elements of Arctic-alpine flora, but all other scenarios that predict increases in CO2 emissions will result in a decreases in the coverage of suitable C. alpina niches, especially in the alpine region. At the same time, an overall expansion of alpine dwarf orchid pollen vectors is predicted, so even within a reduced geographical range, the orchid population will be able to reproduce sexually.

Forest Orchids under Future Climate Scenarios: Habitat Suitability Modelling to Inform Conservation Strategies

Orchidaceae is one of the largest and most diverse families of flowering plants in the world but also one of the most threatened. Climate change is a global driver of plant distribution and may be the cause of their disappearance in some regions. Forest orchids are associated with specific biotic and abiotic environmental factors, that influence their local presence/absence. Changes in these conditions can lead to significant differences in species distribution. We studied three forest orchids belonging to different genera (Cephalanthera, Epipactis and Limodorum) for their potential current and future distribution in a protected area (PA) of the Northern Apennines. A Habitat Suitability Model was constructed for each species based on presence-only data and the Maximum Entropy algorithm (MaxEnt) was used for the modelling. Climatic, edaphic, topographic, anthropogenic and land cover variables were used as environmental predictors and processed in the model. The aim is to identify the environmental factors that most influence the current species distribution and the areas that are likely to contain habitats suitable for providing refuge for forest orchids and ensuring their survival under future scenarios. This will allow PA authorities to decide whether to invest more resources in conserving areas that are potential refuges for threatened species.

Contrasting range changes of terrestrial orchids under future climate change in China

Climate change has impacted the distribution and abundance of numerous plant and animal species during the last century. Orchidaceae is one of the largest yet most threatened families of flowering plants. However, how the geographical distribution of orchids will respond to climate change is largely unknown. Habenaria and Calanthe are among the largest terrestrial orchid genera in China and around the world. In this paper, we modeled the potential distribution of eight Habenaria species and ten Calanthe species in China under the near-current period (1970-2000) and the future period (2081-2100) to test the following two hypotheses: 1) narrow-ranged species are more vulnerable to climate change than wide-ranged species; 2) niche overlap between species is positively correlated with their phylogenetic relatedness. Our results showed that most Habenaria species will expand their ranges, although the climatic space at the southern edge will be lost for most Habenaria species. In contrast, most Calanthe species will shrink their ranges dramatically. Contrasting range changes between Habenaria and Calanthe species may be explained by their differences in climate-adaptive traits such as underground storage organs and evergreen/deciduous habits. Habenaria species are predicted to generally shift northwards and to higher elevations in the future, while Calanthe species are predicted to shift westwards and to higher elevations. The mean niche overlap among Calanthe species was higher than that of Habenaria species. No significant relationship between niche overlap and phylogenetic distance was detected for both Habenaria and Calanthe species. Species range changes in the future was also not correlated with their near current range sizes for both Habenaria and Calanthe. The results of this study suggest that the current conservation status of both Habenaria and Calanthe species should be adjusted. Our study highlights the importance of considering climate-adaptive traits in understanding the responses of orchid taxa to future climate change.

Orchid diversity along an altitudinal gradient in the central Balkans

Understanding patterns of species diversity along an altitudinal gradient is the major topic of much biogeographical and ecological research. The aim of this study was to explore how richness and density of orchid species and subspecies in terms of different categories of underground organ systems and pollination systems vary along an altitudinal gradient in the central Balkans. The altitudinal gradient of the study area was divided into 21 100-m vertical intervals. Data were analyzed using both non-linear and linear regressions with three data sets (total orchids, orchids of forest habitats, orchids of non-forest habitats) in the case of species richness and three data sets (total orchids—total area, forest orchids—forest area, and orchids of non-forest habitats—non-forest area) in the case of species density. The results showed a hump-shaped pattern of orchid richness and density, peaking at 900–1,000 m. The richness and density of orchids of forest habitats are generally slightly greater than the richness and density of orchids of non-forest habitats in lowland areas, whereas the orchids of herbaceous vegetation types dominating at high altitudes. Tuberous orchids dominate in low and mid-altitude areas, orchids with palmately lobed and fusiform tubers (“intermediate orchids”) dominate at high altitudes, while rhizomatous orchids are predominate in mid-altitude forest stands. Both deceptive and self-pollinated orchids show a unimodal trend with a peak at mid-altitude areas. This study underlines the importance of low and mid-altitude areas for the survival of deceptive orchids and the importance of mid- and high-altitude areas for the survival of rewarding orchids. In addition, forest habitats at mid-altitudes have been shown to be crucial for the survival of self-pollinated orchids. The results suggest that the altitudinal patterns of orchid richness and density in the central Balkans are determined by mechanisms related to land area size and habitat cover, partially confirming the species-area relationship (SAR) hypothesis. This study contributes significantly to a better understanding of the potential impacts of habitat changes on orchid diversity, thereby facilitating more effective conservation planning.

The impact of global warming on the niches and pollinator availability of sexually deceptive orchid with a single pollen vector

Orchidaceae are among the most endangered plants in the world. Considering the sensitive nature of pollinator-plant relationship the most vulnerable are species which are dependent on a single pollen vector. In this paper the future distribution of suitable niches of Australian sexually deceptive orchid Leporella fimbriata and its pollinator (Myrmecia urens) was estimated using three machine learning algorithms. While the potential range of fringed hare orchid depending on modelling method will be larger or slightly reduced than currently observed, the ant will face significant loss of suitable niches. As a result of global warming the overlap of orchid and its only pollen vector will most probably decrease. The unavailability of pollen vector will lead to decreased reproductive success and as a result it will be a great threat for L. fimbriata existence.

Epiphytic Orchid Diversity along an Altitudinal Gradient in Central Nepal

Epiphytic orchids are common in subtropical forests, but little is known about the factors that determine their diversity. We surveyed two sites (north-facing Phulchowki and south-facing Shivapuri hills), in the sub-tropical forest in the Kathmandu valley, central Nepal. Along five transects per site, spanning an altitudinal gradient of 1525–2606 m a.s.l., we recorded all epiphytic orchids and the host species on which they were growing. The data were analyzed using a generalized linear model (GLM) and redundancy analysis (RDA). Species richness significantly decreased with increasing altitude and was higher in larger hosts and in places with high temperature. Species composition was affected by altitude, distance from the forest edge, host type, and precipitation. This study indicates that the most important factors affecting epiphytic orchid diversity was altitude, even if other factors were associated with patterns in composition. The low-altitude habitats with high species diversity are the best places for epiphytic orchids in this region. The altitudinal species richness and patterns in composition revealed by this study provide a baseline for further studies on epiphytic orchids.

Distribution of Orchids with Different Rooting Systems in the Czech Republic

Understanding diversity patterns along altitudinal gradients and the effect of global change on abundance, distribution patterns and species survival are of the most discussed topics in biodiversity research. Here, we determined the associations of orchid species richness and the degree of their specialization to specific environmental conditions (expressed by species specialization index) with altitude in six floristic areas in the Czech Republic. We distinguished three basic trends in these relationships: linear, parabolic and cubic. We then determined whether these trends differ between three orchid groups classified by their rooting systems: rhizomatous, intermediate and tuberous. We used distributional data on 69 species and subspecies of terrestrial orchids recorded in the Czech Republic and interpolated them at 100-m intervals along an altitudinal gradient in each floristic area. The trends in both species richness and mean species specialization index differed between the six floristic areas within each of the three orchid groups studied. These patterns are probably strongly influenced by the orography of the country and the distribution of different habitats in the six floristic areas in the Czech Republic. We also found that the most widely distributed orchid group in the Czech Republic are the rhizomatous orchids, followed by intermediate and tuberous ones.

Phytogeographical Analysis and Ecological Factors of the Distribution of Orchidaceae Taxa in the Western Carpathians (Local study)

In the years 2018-2020, we carried out large-scale mapping in the Western Carpathians with a focus on determining the biodiversity of taxa of the family Orchidaceae using field biogeographical research. We evaluated the research using phytogeographic analysis with an emphasis on selected ecological environmental factors (substrate: ecological land unit value, soil reaction (pH), terrain: slope (°), flow and hydrogeological productivity (m².s^-1) and average annual amounts of global radiation (kWh.m^-2). A total of 19 species were found in the area, of which the majority were Cephalenthera longifolia, Cephalenthera damasonium and Anacamptis morio. Rare findings included Epipactis muelleri, Epipactis leptochila and Limodorum abortivum. We determined the ecological demands of the abiotic environment of individual species by means of a functional analysis of communities. The research confirmed that most of the orchids that were studied occurred in acidified, calcified and basophil locations. From the location of the distribution of individual populations, it is clear that they are generally arranged compactly and occasionally scattered, which results in ecological and environmental diversity. During the research, we identified 129 localities with the occurrence of 19 species and subspecies of orchids. We identify the main factors that threaten them and propose specific measures to protect vulnerable populations.

Orchid Extinction over the Last 150 Years in the Czech Republic

Understanding temporal changes in the distribution and abundance of various species is one of the key goals of conservation biology. During recent decades, the abundance and distribution of many species of plants and animals have declined dramatically, mainly because of habitat loss and fragmentation. The purpose of this study is to analyze the rate of extinction of orchids at various sites in different 20-year time intervals over the last 150 years, determined according to changes in society. Using the dataset of the orchid records of the Nature Conservation Agency of the Czech Republic, we determined the disappearance rate of orchids from sites using a grid of 1 × 1 km. We found that the vast majority of orchids disappeared from many of their historical localities in all time intervals analyzed. The number of sites suitable for Czech orchids declined by 8–92%, depending on the species. The most threatened orchid species in the Czech Republic are Spiranthes spiralis, Anacamptis palustris, Epipogium aphyllum and Goodyera repens. This all seems to be closely related with changes in agricultural practices in the open as well as in forest habitats. Preserving suitable orchid habitats seems to be the key for keeping Czech orchid flora alive.

The Impact of Human Pressure and Climate Change on the Habitat Availability and Protection of Cypripedium (Orchidaceae) in Northeast China

Human pressure on the environment and climate change are two important factors contributing to species decline and overall loss of biodiversity. Orchids may be particularly vulnerable to human-induced losses of habitat and the pervasive impact of global climate change. In this study, we simulated the extent of the suitable habitat of three species of the terrestrial orchid genus Cypripedium in northeast China and assessed the impact of human pressure and climate change on the future distribution of these species. Cypripedium represents a genus of long-lived terrestrial orchids that contains several species with great ornamental value. Severe habitat destruction and overcollection have led to major population declines in recent decades. Our results showed that at present the most suitable habitats of the three species can be found in Da Xing’an Ling, Xiao Xing’an Ling and in the Changbai Mountains. Human activity was predicted to have the largest impact on species distributions in the Changbai Mountains. In addition, climate change was predicted to lead to a shift in distribution towards higher elevations and to an increased fragmentation of suitable habitats of the three investigated Cypripedium species in the study area. These results will be valuable for decision makers to identify areas that are likely to maintain viable Cypripedium populations in the future and to develop conservation strategies to protect the remaining populations of these enigmatic orchid species.

Species Richness, Ecology, and Prediction of Orchids in Central Europe: Local-Scale Study

Orchids are one of the most species-rich families in the world, and many species are under threat in numerous countries. Biodiversity research focusing on the relationship between the richness of orchid species and ecological factors was performed across the Cerová vrchovina Mts (Western Carpathians) testing impact of 26 explanatory variables. We aimed to determine the main ecological predictors controlling species richness and to predict potential species richness patterns. Altogether, 19 orchid species were found in the studied area, with Cephalanthera damasonium and Epipactis microphylla being the most common. Four environmental predictors (minimal longitude, carbonate-containing sediments, maximal yearly solar irradiation, and agricultural land) had statistically significant effects on orchid richness following regression analysis. Predictive models for the nine most frequent species using MaxEnt software showed (i) that land cover and geological substrate had the highest contribution to the explained variance in the models and (ii) strong potential for occurrence of given orchids in several poorly mapped parts of the studied area.