Gerhard Zotz

Carl von Ossietzky University of Oldenburg · Department of Biology and Environmental Sciences (IBU)

About 14% of all fern species have chlorophyllous spores. Unlike their counterparts, chlorophyllous spores lack dormancy and have a shorter viability (i.e. only a few days in some species). Such spores should limit long-distance dispersal and be more susceptible to harsher climatic conditions raising questions about the evolutionary and ecological...

Aim Endemic species, characterised by limited geographic ranges, face a high risk of extinction. The neotropical region harbours diverse ecosystems and a substantial number of endemic species, thus identifying areas of high endemism is crucial for protecting unique and threatened species and ecosystems. Vascular epiphytes—nonparasitic plants that g...

Mitigating ongoing losses of insects and their key functions (e.g. pollination) requires tracking large‐scale and long‐term community changes. However, doing so has been hindered by the high diversity of insect species that requires prohibitively high investments of time, funding and taxonomic expertise when addressed with conventional tools. Here,...

There are a number of rather anecdotal reports of plant growth on power cables in the Americas, but until now there has been no systematic attempt to gauge the geographical extension of this phenomenon nor a documentation of the diversity of species found there. Using observations from the participatory science data platform iNaturalist and the sci...

Epiphytes develop anatomical features to improve efficiency of the uptake of water and nutrients, such as absorptive foliar scales or a velamen radicum. Despite substantial studies on the occurrence, morphology, development and phylogeny of the velamen, most of the available literature is focused on Orchidaceae, making current knowledge on velamen...

Climate change and other anthropogenic disturbances are increasing liana abundance and biomass in many tropical and subtropical forests. While the effects of living lianas on species diversity, ecosystem carbon, and nutrient dynamics are receiving increasing attention, the role of dead lianas in forest ecosystems has been little studied and is poor...

Background In contrast to woody climbers, information on community composition or vertical extension within the forest is scarce for herbaceous climbers, even in well‐studied field sites like Barro Colorado Island. Moreover, questions regarding ontogenetic patterns (site of germination, changes in root/shoot connection with the soil) are unresolved...

The velamen radicum, a rhizodermis that consists of dead cells at maturity, is often described as typical for epiphytic aroids. Such claims are surprising on two grounds: (1) there are hardly any data on this trait for aroids and (2) the link between a velamen and epiphytic growth has recently been challenged in general. We performed an anatomical...

Premise Bryophytes and lichens have important functional roles in many ecosystems. Insight into how their CO 2 exchange responds to climatic conditions is essential for understanding current and predicting future productivity and biomass patterns, but responses are hard to quantify at time‐scales beyond instantaneous measurements. We present PoiCar...

The Neotropical realm hosts some of the Earth's most species-rich biodiversity hotspots, with vascular epiphytes significantly contributing to this diversity, regionally accounting for up to 39% of the vascular flora. However, many regions of the Neotropics where epi-phytic species of restricted distribution are reported coincide with threatened ec...

Background and Aims Substrate preferences are often treated as species traits and are used to distinguish different habits, i.e. an epiphytic, lithophytic or terrestrial habit. Such a categorization ignores, however, substantial intraspecific variation. An approach that takes biological variability within a species into account is needed. Methods...

Understanding the mechanisms driving community assembly has been a major focus of ecological research for nearly a century, yet little is known about these mechanisms in commensal communities, particularly with respect to their historical/evolutionary components. Here, we use a large-scale dataset of 4,440 vascular plant species to explore the rela...

Velamen radicum, a dead tissue at maturity, characterizes the roots of many epiphytes. Apart from a role in water and nutrient uptake, protection against excessive radiation in the upper forest canopy has also been suggested, but this function has never been critically assessed. To test this notion, we studied the roots of 18 species of Orchidaceae...

The Neotropical realm hosts some of the Earth’s most species-rich biodiversity hotspots, with vascular epiphytes significantly contributing to this diversity. However, many regions of the Neotropics where epiphytic species of restricted distribution are reported coincide with threatened ecosystems, such as the tropical montane cloud forest. Moreove...

Vascular epiphytes represent c. 10% of all vascular plant species. In epiphytes, attachment is essential for survival throughout consecutive ontogenetic stages of their life, starting with: (1) initial propagule attachment to the host; followed by (2) the development of first root‐substrate connections; and (3) maintenance of this attachment despit...

The epiphytic orchid Caularthron bilamellatum sacrifices its water storage tissue for nutrients from the waste of ants lodging inside its hollow pseudobulb. Here, we investigate whether fungi are involved in the rapid translocation of nutrients. Uptake was analysed with a ¹⁵N labelling experiment, subsequent isotope ratio mass spectrometry (IRMS) a...

Similar to plants in many other families, members of the Hymenophyllaceae use numerous substrates for growth, e.g., soil, rocks or tree bark. However, substrate preference does not only differ among species but can also vary among members of the same species. There have been several attempts in the past to appropriately capture this variation, but...

Background and Scope The epiphytic life form characterizes almost 10 % of all vascular plants. Defined by structural dependence throughout their life and their non-parasitic relationship with the host, the term epiphyte describes a heterogenous and taxonomically diverse group of plants. This article reviews the importance of crassulacean acid metab...

Here we provide the ‘Global Spectrum of Plant Form and Function Dataset’, containing species mean values for six vascular plant traits. Together, these traits –plant height, stem specific density, leaf area, leaf mass per area, leaf nitrogen content per dry mass, and diaspore (seed or spore) mass – define the primary axes of variation in plant form...

The Bromeliaceae family has been used as a model to study adaptive radiation due to its terrestrial, epilithic, and epiphytic habits with wide morpho-physiological variation. Functional groups described by Pittendrigh in 1948 have been an integral part of ecophysiological studies. In the current study, we revisited the functional groups of epiphyti...

Tank bromeliads are unique canopy microhabitats that offer freshwater and organic nutrient-rich substrates in the Neotropics. In them it is possible to thoroughly characterize environmental factors and species composition of terrestrial and aquatic biota. Therefore, these plants have been used as natural models to study how communities are distribu...

Premise: Approximately 14% of all fern species have physiologically active chlorophyllous spores that are much more short-lived than the more common and dormant achlorophyllous spores. Most chlorophyllous-spored species (70%) are epiphytes, and these account for almost 37% of all epiphytic ferns. Chlorophyllous-spored ferns are also overrepresente...

Climate change is a mounting global issue, but its consequences will be variable across regions. Tropical species are hypothesized to have reduced climatic adaptability and plasticity. Yet, relative to temperate species, less is understood about how they will respond to climate change. Rising temperature and atmospheric CO2 could impact plant–herbi...

Vascular epiphytes are an important component of many ecosystems and constitute a substantial part of global plant diversity. In this context, accidental epiphytism, that is, the opportunistic epiphytic growth of typically terrestrial species, deserves special attention because it provides crucial insights into the global distribution of vascular e...

Variation in leaf functional traits along environmental gradients can reveal how vascular epiphytes respond to broad‐ and small‐scale environmental gradients. Along elevational gradients, both temperature and precipitation likely play an important role as drivers of leaf trait variation, but these traits may also respond to small‐scale changes in l...

Background and Aims In the roots of most vascular plants, the growth zone is small, the meristem and the elongation zone are sharply separated, and only meristematic cells divide. This statement is based almost entirely on studies with soil-rooted plants. Whether aerial roots of structurally dependent (=epiphytic/hemiepiphytic) species differ is vi...

El término hemiepífitas ha sido usado para las aráceas y otras trepadoras (p.ej. Clusia, Ficus), a veces distinguiendo entre hemiepífitas primarias (HP) y secundarias (HS) como formas de crecimiento diferentes. (Putz y Holbrook 1986; Gentry y Dodson 1987; Nadkarni et al. 2001). Las HP germinan y pasan su estado juvenil como epífitas y posteriorment...

Premise: For vascular epiphytes, secure attachment to their hosts is vital for survival. Yet studies detailing the adhesion mechanism of epiphytes to their substrate are scarce. Examination of the root hair-substrate interface is essential to understand the attachment mechanism of epiphytes to their substrate. This study also investigated how subs...

As climate change leads to increasing temperatures, tropical dry seasons are expected to become more severe. An overall intensification of drought events may strongly affect vascular epiphytes. Especially at the community level, the response of epiphytes to intense drought events is still poorly understood. Therefore, the severe El Niño event of 20...

Many bromeliads occur in habitats that are potentially affected by salt. Pitcairnia halophila is a particularly interesting case in this context due to its growing sites in the spray zone of coastal cliffs in Central America. We conducted an experimental/observational study that explored the physiological and ecological basis of the occurrence of t...

Several studies of hurricane damage on epiphyte communities implied that epiphytes might be in danger of being blown off their host when subjected to strong wind. There is very limited knowledge about the mechanical impact that wind may have on epiphytes. Using a wind-triggered camera set-up, we observed how epiphytic tank bromeliads are affected b...

With over a millennium history of cultivation, Cymbidium species and hybrids is one of the most commercially important orchids in world floriculture industry. The Cymbidium genus has near 75 species with ornamental and medicinal importance and thousands of hybrids used for pot and cut flower production. Plant tissue culture techniques for breeding...

Habitat heterogeneity is considered a primary causal driver underpinning patterns of diversity, yet the universal role of heterogeneity in structuring biodiversity is unclear due to a lack of coordinated experiments testing its effects across geographic scales and habitat types. Furthermore, key species interactions that can enhance heterogeneity,...

Future climate‐change effects on plant growth are most effectively studied using microclimate‐manipulation experiments, the design of which has seen much advance in recent years. For tropical forests, however, such experiments are particularly hard to install and have hence not been widely used. We present a system of active heating and CO2 fertili...

Vascular epiphytes represent almost 10% of all terrestrial plant diversity. Despite the extensive research on the functional ecology and challenges of epiphytic growth, there is still very little known on how exposure to mechanically induced stress affects the growth and development of epiphytes. Therefore, this study investigated the effect of suc...

Understanding the degree to which deterministic and stochastic processes drive community assembly is an ongoing focus of research in community ecology. This effort is strongly biased towards ground‐rooted plants, resulting in a limited understanding of communities of other life‐forms, such as structurally dependent plants. Vascular epiphytes are se...

Bromeliads are the most abundant litter-trapping plants in Neotropical forest canopies. By intercepting litter, bromeliads obtain and retain nutrients before they reach the pedosphere. Here, we analyzed the litter captured and stored by tank bromeliads (TB) in five different forests along an elevation gradient in Mexico. Among those forests, carbon...

Plants and animals evolve different attachment structures and strategies for reversible or permanent adhesion to different substrate types. For vascular epiphytes, having the ability to permanently attach to their host plants is essential for establishment and survival. Unlike mistletoe roots, roots of vascular epiphytes do not penetrate the host t...

Plant functional traits impact the fitness and environmental niche of plants. Major plant functional types have been characterized by their trait spectrum, and the environmental and phylogenetic imprints on traits have advanced several ecological fields. Yet, very few trait data on epiphytes, which represent almost 10% of vascular plants, are avail...

The epiphytic life form characterizes almost 10% of all vascular plants. Defined by their mechanical dependence throughout their life and their non‐parasitic relationship with the host, the term epiphyte describes a very heterogenous and taxonomically diverse group of plants. This article explores the functional ecology of this group, acknowledging...

This data paper describes a new, comprehensive database (BIOVERA-Epi) on species distributions and leaf functional traits of vascular epiphytes, a poorly studied plant group, along gradients of elevation and forest-use intensity in the central part of Veracruz State, Mexico. The distribution data include frequencies of 271 vascular epiphyte species...

For decades, tropical ecologists distinguished primary (PH) and secondary hemiepiphytes (SH) as two structurally dependent life forms with an epiphytic phase at, respectively, the beginning or the end of their ontogeny. However, the use of these terms has been criticized repeatedly because the term “hemiepiphyte” suggests an unsubstantiated biologi...

Aim Vascular epiphytes are ubiquitous components of wet tropical forests where they contribute substantially to local and regional plant diversity. While some basic epiphyte distribution patterns are relatively well studied, little effort has been made to understand the drivers responsible for constraining their global distribution. This study quan...

Tropical forests are the most diverse terrestrial ecosystems and home to numerous tree species competing for resources in space and time. Functional traits influence the ecophysiological performance of tree species, yet the relationship between traits and emergent long-term growth patterns is poorly understood. Here, we present a novel 3D forest st...

Metacommunity ecology currently lacks a consistent functional trait perspective across trophic levels. To foster new cross‐taxa experiments and field studies, we present hypotheses on how three trait dimensions change along gradients of density of individuals, resource supply and habitat isolation. The movement dimension refers to the ability to mo...

This data paper describes a new, comprehensive database (BIOVERA-Epi) on species distributions and leaf functional traits of vascular epiphytes, a poorly studied plant group, along gradients of elevation and forest-use intensity in the central part of Veracruz State, Mexico. The distribution data includes frequencies of 271 vascular epiphyte specie...

Vascular epiphytes represent almost 10% of all terrestrial plant diversity. Being structurally dependent on trees, epiphytes live at the interface of vegetation and atmosphere, making them susceptible to atmospheric changes. Despite the extensive research on vascular epiphytes, little is known about wind disturbance on these plants. Therefore, this...

Hemiepiphytic plants are defined by their ontogeny. They germinate on a host tree but later establish root contact with the soil. Most hemiepiphytes remain structurally dependent on their host for their entire life, but some, often referred to as stranglers, develop pseudotrunks that allow them to outlive their host. Unfortunately, the terminology...

Vascular epiphytes represent almost 10% of all terrestrial plant diversity. Despite their growing sites exposed to frequent extensive storms, nothing is known about how external mechanical perturbations by wind affects epiphytes’ growth and development. Therefore, this study investigated the effect of such mechanical stress on the growth rate and m...

Endophytic fungi are known to be present in roots of salt marsh plants, but their ecological role in this symbiosis is still largely unknown. Generally considered parasitic or saprophytic, they may still be mutualistic, at least under certain circumstances. Among salt marsh plants, Salicornia spp. are recognized as particularly salt-tolerant and th...

Aim Vascular epiphytes are ubiquitous features of wet tropical forests where they contribute substantially to local and regional plant diversity. While some basic epiphyte distribution patterns are relatively well studied, little effort has been made to understand the drivers responsible for constraining their global distribution. This study quanti...

Background and Aims: The species of Araceae are known for their diversity of life forms; however, the terminology regarding this group generates conceptual confusion within the scientific community. Our objective was to demonstrate the current conceptual confusion based on the literature, herbarium vouchers vs. observations and field data. Methods...

Bromeliads are recognized as vital habitats for arboreal amphibians. However, these plants are often not included in traditional amphibian surveys. Furthermore, focused canopy sampling techniques are time-consuming, require specialized equipment and training, and, in the case of bromeliads, sampling is typically destructive. In this study, we devel...

Epiphytes make up roughly 10% of all vascular plant species globally and play important functional roles, especially in tropical forests. However, to date, there is no comprehensive list of vascular epiphyte species. Here, we present EpiList 1.0, the first global list of vascular epiphytes based on standardized definitions and taxonomy. We include...

Lower montane tropical forests are typically characterized by substantial epiphyte loads. One of the important ecological roles of epiphytes in these forest systems is the interception of rainwater with a major impact on forest hydrology. Several morphological traits of epi-phytes assure a dependable water supply and greatly increase the water-hold...

• Forest canopies play a crucial role in structuring communities of vascular epiphytes by providing substrate for colonization, by locally varying microclimate, and by causing epiphyte mortality due to branch or tree fall. However, as field studies in the three‐dimensional habitat of epiphytes are generally challenging, our understanding of how for...

Despite the ecological importance of vascular epiphytes in the tropics, even basic information on the processes that form epiphyte communities is scarce. This is partially due to an almost complete lack of long‐term studies. Here, we present data that were collected in three consecutive censuses over 21 years in a monospecific host tree system that...

Trait matching between interacting species may foster diversity. Thus, high epiphyte diversity in tropical forests may be partly due to the high diversity of trees and some degree of host specificity. However, possible trait matching between epiphyte and host is basically unexplored. Since the epiphytic habitat poses particular challenges to plants...