Ongoing EpIG projects
The following projects are currently ongoing and use data of EpIG-DB to
answer questions about vascular epiphytes at the Neotropical scale.
Drivers of vascular epiphyte diversity in the Neotropics
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Vascular epiphytes, non-parasitic plants growing on other plants, are crucial to tropical forest canopies. They comprise about 10% of the world's vascular plant diversity and 39% in the Neotropics. They provide vital ecological services and influence canopy structure and complexity. Their distribution is shaped by elevation and latitude, with low water availability adaptations possibly limiting their cold tolerance. Epiphyte richness declines with latitude faster than terrestrial plants and peaks at mid-elevations. The impact of regional differences on epiphyte diversity needs to be better understood, with most studies being localized. Recent research has pointed out the need for more comprehensive studies on species richness and abundance at larger scales. Understanding these biodiversity patterns is essential, especially with global change.
This study aims to identify the drivers of Neotropical epiphyte diversity using a new database with data from 9,000 host trees, 150,000 epiphyte individuals, and 1,500 species across 25 ecoregions. Using advanced modelling techniques, we will analyse elevational and latitudinal patterns of richness and abundance, considering environmental, geographical, and historical factors. We expect climatic variables, especially temperature and precipitation, to significantly influence these patterns, with temperature increasing abundance and precipitation limiting richness. |
Effect of tree size on ecosystem decay
Leading Researchers:
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Objective
To elucidate the impacts of habitat disturbance on epiphyte community structure, contributing to conservation strategies for species reliant on complex vertical habitats in fragmented landscapes. The aim of this project is to investigate the relationship between tree size and epiphyte species richness (TS-ER), analyzing how this relationship is affected by different levels of habitat disturbance. The specific aims are: (1) Is there a significant relationship between tree size and species richness, accounting for the number of individuals sampled? (2) How does land-use type affect the strength of ecosystem decay (Sn)? (3) Are macroecological trends in ecosystem decay consistent across different land-use categories? The study examines patterns of ecosystem decay in epiphyte communities inhabiting three habitat types: preserved forests, secondary forests, and anthropogenic environments. We propose an innovative approach that combines ecological analyses at a multispatial scale to understand how alterations in tree size and habitat characteristics impact epiphytic biodiversity. This research will contribute to a better understanding of the effects of habitat disturbance on epiphyte communities and provide key information for future conservation strategies in fragmented landscapes. |
Scale-dependent forest cover impacts on Neotropical epiphytes
Objective
To understand the human impact on forest patches and determine its effect on Neotropical vascular epiphyte diversity across multiple spatial scales, evaluating responses at both the local (patch) and landscape (regional) levels. (1) How does the local degree of perturbation (Natural, Semi-natural, and Anthropogenic) influence vascular epiphyte alpha, beta, and gamma diversity at the patch scale? (2) Is regional species loss (Gamma Diversity) a strictly area-dependent process (Passive Sampling), or is it exacerbated by environmental degradation and habitat quality decline (Ecosystem Decay)? (3) Does forest cover loss trigger community biotic homogenization (reduced beta diversity) in preserved habitats, or does it lead to stochastic divergence/Beta Inversion (increased beta diversity via ecological drift) in highly disturbed, isolated remnants?This project leverages the newly expanded, unpublished version 2.0 of the EpIG-DB (Epiphytes Inventory Group) database, representing a massive five-fold increase in sampling effort (growing to 97 independent studies and 24,356 sampled host trees across 25 Neotropical ecoregions). By focusing on presence/absence and abundance data at the host-tree level, this study establishes a fundamental macroecological baseline. Innovative features include: High-Precision Spatial Grain: Utilization of a fine-scale resolution (0.125∘×0.125∘) to minimize the "mixed-pixel" problem and isolate land-use signals. Spatio-Temporal Synchronization: Integration of a 40-year historical window of forest cover transitions (HILDA+ global dataset) to capture historical landscape connectivity and legacy effects. Advanced Analytical Framework: Use of Hill numbers (q=0 and q=2) combined with sample-unit-based rarefaction/extrapolation (iNEXT), on gamma, alpha and beta scales. Hypothesis-Driven Model Tournament: Evaluating a symmetrical candidate set of 16 Hierarchical Bayesian Models via brms/Stan to robustly adjudicate between competing ecological frameworks (e.g., passive sampling vs. ecosystem decay; biotic homogenization vs. beta inversion) without data-dredging risks. |
Leading Researchers:
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Climate challenges: assessing the future landscape for Neotropical
vascular epiphytes and protected areas
Climate change is causing a global-scale biological response, impacting species richness, composition, and distribution globally, causing extinction or range shifts. Among the 100,000 Neotropical seed plants, vascular epiphytes stand out for their ability to thrive in various forest canopy environments, supporting diverse fauna. Their richness patterns may be similar to that of other plants and even animals, making them important for studying climate change effects, as they can serve as a model to forecast the impact of global changes on the distribution of different taxa. Epiphytes, with their wind-dispersed seeds, short life cycles, and rapid colonization, are suitable climate change indicators. This study will use species distribution models (SDMs) to predict future changes in the distribution and protected area coverage of Neotropical vascular epiphytes under different carbon emission scenarios (e.g., SSP370 and SSP585). We expect that climate change will reduce both the distribution area of these species and the percentage occurring in protected areas. To manage computational demands, we will pre-select species based on climatic niche analysis, focusing on those most likely to be displaced by climate change.
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Spatial distribution of Protected Areas (blue) throughout nonintact (yellow) and intact land (green). Ward. et al. 2020. Just ten per cent of the global terrestrial protected area network is structurally connected via intact land. Nat Commun.
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Global biogeography of Neotropical vascular epiphytes
Contact: Derio Antonio Jiménez-López (PhD student) Departamento de Conservación de la Biodiversidad, El Colegio de la Frontera Sur, San Cristóbal de las Casas, Mexico. The Earth’s terrestrial surface Neotropics are divided into biogeographical regions shaped by complex due to their evolutionary history. Understanding the formation of biogeographical regions and their boundaries is fundamental to explaining floral evolution between these regions is key to studying the evolution of floras. Vascular epiphytes are an ideal group for illustrating this regionalization. However, current knowledge is often geographically biased on Neotropical epiphytes and is biased at the regional scale. While contemporary climate is known to influence epiphyte distribution, historical factors like geological and climatic changes also shape current biogeographic patterns.
We propose to investigate the global phytogeographical regionalization of vascular Neotropical epiphytes, the contributions of ecological and historical factors, and the ancestral ranges and diversification areas of the main epiphyte families. To do this, we will conduct a literature review to create a workflow for constructing biogeographic regions. Using a standardised workflow, wethis workflow, we will create regions for all Neotropical epiphytes by integrating global databases with phylogenetic megatrees. with data from the EpiG database and phylogenetic megatrees. We will use linear models with phylogenetic beta diversity as the response variable and ecological and historical factors as predictors. |
Taxonomic and phylogenetic regionalisation of epiphytic Polypodiaceae across the Neotropics.
We expect to identify distinct global regions: (1) The NeotropicsAndes, with highland species and high diversity; (2) The Indo-Malayan, characterised by rich orchid and fern assemblagesAmazon, with lowland species; (3) The Afrotropics, showing unique evolutionary trajectories; and The Brazilian Atlantic, with many endemic species; and (4) AustralasiaMesoamerica, influenced by Gondwana history South American flora. We anticipate a strong floristic distinction between these regions. and that the ancestral areas of the highest species richness or endemism will be in the Andes, Amazon, or Brazilian Atlantic.
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The biogeography and conservation priorities of Neotropical vascular
epiphytes (BIOCON-VEP)
Contact: Maria Judith Carmona-Higuita (PhD student)
Faculty of Biology, University of Marburg, Marburg, Germany The Neotropics, rich in biodiversity, are threatened by land use and climate change, making the preservation of its ecosystems urgent. Vascular epiphytes, vital yet vulnerable to these threats, have gained attention for their ecological significance. This research aims to elucidate Neotropical vascular epiphytes' biogeographical patterns and conservation priorities, addressing key gaps in our understanding of their distribution and vulnerability. I will map the geographic distribution of epiphyte species using species distribution models based on biodiversity records and environmental data, which will reveal their geographic ranges and potential responses to climate and land-use changes. Next, I will analyze endemism patterns among Neotropical epiphytes, identifying regions with unique and rare species to inform targeted conservation efforts. I will conduct species-level conservation assessments to identify those at the highest risk of extinction according to IUCN Red List criteria. Collaborating with experts and taxonomists across Latin America, we aim to establish a dedicated epiphyte IUCN group. These assessments will form the foundation for conservation efforts and policy development. |
Number of endemics per biogeographic provinces of all vascular epiphyte species combined (total) and the five richest families in the Neotropics individually, based on convex polygons (Carmona-Higuita et al. In revision).
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The anticipated outcomes include mapping diversity and endemism hotspots for epiphytes, species distribution maps, and an updated IUCN Red List of epiphytes. This research will also generate ranked lists of priority species and areas for conservation. By enhancing our understanding of vascular epiphytes and their vulnerabilities, this study supports the preservation of biodiversity and sustainable ecosystems in the Neotropics, addressing the region's ongoing biodiversity crisis.
Trait matching between epiphytes and host trees
Vascular epiphytes complete their life cycle on host trees without parasitising them, forming commensalistic interactions that remain poorly understood. While ecological network analyses have traditionally focused on mutualistic and antagonistic interactions, commensalistic systems — particularly those between epiphytes and their hosts — have received far less attention. Existing studies often rely on metrics developed for co-evolutionary interactions, despite evidence that epiphyte–host relationships lack strong phylogenetic structure. Host preference therefore remains unclear, with patterns described as neither strictly host-specific nor entirely random. Host species may instead act as proxies for structural traits that create suitable microclimatic conditions for epiphyte establishment.
This project will evaluate trait matching between epiphytes and host trees using innovative and complementary modelling approaches. We will apply machine learning techniques to identify combinations of host and epiphyte traits that best explain interaction patterns, offering advantages over traditional regression frameworks. In parallel, we will use the Hierarchical Modelling of Species Communities (HMSC) framework to integrate species occurrences, environmental covariates, functional traits and phylogenetic relationships within a joint species distribution modelling approach.
By combining these methods, the study will provide a large-scale assessment of the mechanisms shaping commensalistic interactions. We expect to identify key structural host traits that drive epiphyte establishment and to clarify how trait matching influences community assembly in epiphyte–host networks.
This project will evaluate trait matching between epiphytes and host trees using innovative and complementary modelling approaches. We will apply machine learning techniques to identify combinations of host and epiphyte traits that best explain interaction patterns, offering advantages over traditional regression frameworks. In parallel, we will use the Hierarchical Modelling of Species Communities (HMSC) framework to integrate species occurrences, environmental covariates, functional traits and phylogenetic relationships within a joint species distribution modelling approach.
By combining these methods, the study will provide a large-scale assessment of the mechanisms shaping commensalistic interactions. We expect to identify key structural host traits that drive epiphyte establishment and to clarify how trait matching influences community assembly in epiphyte–host networks.
Finished EpIG Projects
EpIG-DB: A database of vascular epiphyte assemblages in the Neotropics.
Phylogenetic diversity and the structure of host-epiphyte interactions across the Neotropics.
Conservation status of vascular epiphytes in the neotropics.
Endemism Centres of the Five Richest Vascular Epiphyte Families in the Neotropics.
A global bioregionalisation for orchids.
Phylogenetic diversity and the structure of host-epiphyte interactions across the Neotropics.
Conservation status of vascular epiphytes in the neotropics.
Endemism Centres of the Five Richest Vascular Epiphyte Families in the Neotropics.
A global bioregionalisation for orchids.
EpIG is funded by:
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Design and content by Glenda Mendieta-Leiva, Derio Antonio Jiménez López, Maria Judith Carmona Higuita and contributors (previously: Rosa María Villanueva Espinoza & Helena Einzmann).