Suitable Microhabitats Research Articles

Pit builders are assisted by walls to find suitable sites for pit construction but are slowed down by obstacles and their initial distance from the destination

Abstract Habitat selection plays a critical role in the survival and reproduction of animals, with implications for all important behaviours. Animals are often limited in their familiarity with their habitat and rely on their senses and the habitat structure to detect suitable sites to settle in. We focus here on a trap‐building predator, the wormlion, which constructs pitfall traps in loose soil, and examine how the distance from suitable microhabitats and the presence of obstacles affect its habitat selection. We conducted four experiments. Experiment 1 assessed the impact of distance on the probability of wormlions reaching a suitable microhabitat. Experiment 2 examined the interaction between distance and obstacles. Experiment 3 investigated the influence of walls on the probability of reaching destinations. Experiment 4 evaluated walls as either leading paths or barriers. Our results showed that increasing distance from the destination negatively affected the probability of wormlions reaching it, with larger individuals more likely to cover greater distances. Obstacles interacted with distance, generally decreasing movement when present. Walls positively influenced orientation, aiding wormlions in reaching suitable sites, either by following the wall or locating the destination along the wall. The function of walls varied, sometimes facilitating movement and sometimes decreasing it, depending on their orientation and context. These findings suggest that walls may serve as navigational aids for wormlions in urban environments, assisting them in locating suitable microhabitats. This has implications for understanding habitat selection in urban ecosystems. Future research should explore the long‐term effects of walls on wormlion survival and habitat quality in more natural settings.

Hot-spots of epiphytic and epixylic lichens in fragmented temperate forests are underpinned by microhabitat heterogeneity and spatiotemporal habitat continuity

Habitat loss, fragmentation and degradation are major causes of the ongoing decline of epiphytic and epixylic lichen species in temperate forests throughout Europe. We investigated how extant species richness and composition of epiphytic and epixylic lichen communities in ten hot-spots of lichen diversity in the Czech Republic reflected the occurrence and properties of potentially suitable microhabitats and habitats. At each hot-spot, we surveyed a pair of 1-ha square plots, one in (over-)mature managed and the second in unmanaged forest. In total, we recorded 513 epiphytic and epixylic lichen species which represent a substantial part of lichen biota in Central Europe. Species richness and composition of lichen communities were explained by microhabitat heterogeneity, and also by the area of near-natural forest habitats (habitat extent) at the landscape scale. In addition, lichen species richness and number of red-listed species were explained by a categorial variable distinguishing mature managed and unmanaged plots, used as a proxy of temporal continuity of natural succession. This finding illustrates that temporal continuity of natural succession in unmanaged forests likely had an extra stimulus for lichen communities that may not be reflected by observed aspects of forest habitats. Hence, we confirmed indispensable positive effects of (micro)habitat heterogeneity, and spatial and temporal continuity for preserved hot-spots of lichen diversity in Central Europe. Due to generally slow colonization-extinction dynamics of epiphytic and epixylic lichens we call for strengthening microhabitat heterogeneity, and the spatial and temporal continuity of European temperate forests at the landscape scale.

Pre‐loved home: Egg clutches of the striped marsh frog, Limnodynastes peronii, detected in water‐filled burrows created by the hunter hairy crayfish, Cherax setosus

AbstractMany animals create their own microhabitats that are not naturally present in the environment, such as nests and burrows, which are extended phenotypes that perform tasks related to survival and reproduction. Animals may be able to avoid the costs of implementing their own extended phenotypes by exploiting those already created by other species, including structures that are not actively in use or abandoned. Herein, we report on the striped marsh frog, Limnodynastes peronii, from Australia utilizing crayfish burrows for depositing their egg clutches. Field observations revealed large numbers of recently hatched L. peronii tadpoles in two flooded burrows likely created by the hunter hairy crayfish, Cherax setosus, near an ephemeral wetland pond on Kooragang Island, Australia that had partially dried. Our observations indicate that L. peronii may opportunistically exploit crayfish burrows which, when flooded, become suitable aquatic sites for breeding. These small waterbodies may provide fitness benefits to offspring, reducing exposure to aquatic predators found in naturally occurring aquatic systems but at the expense of increasing competition and cannibalism among confined siblings. These burrows may provide suitable microhabitat refuge during droughts, and breeding habitat for amphibians when other typical breeding habitats may not exist due to wetland drying. This is an example of an amphibian using an extended phenotype of a crustacean for the purposes of reproduction, revealing a unique interaction between these species that has not been reported.

Wild mice in an urbanized world: Effects of light at night under natural and laboratory conditions in the single-striped grass mouse (Lemniscomys rosalia)

ABSTRACT Urbanization, and the accompanying artificial light at night (ALAN), can disrupt the activity of animals. Such disruptions at the base of a food web can ripple through the ecosystem. Most studies of ALAN are performed in the laboratory. Thus, we lack basic information about the circadian responses of animals under natural environmental conditions to fully evaluate the impact of ALAN. We studied the behaviour and activity of wild-caught, peri-urban single-striped grass mice (Lemniscomys rosalia) under a natural treatment and in a standard laboratory treatment, including dim light at night to mimic conditions that they could experience. The species exhibited predominantly crepuscular activity under all experimental treatments. It showed the highest level of activity under the natural treatment, whereas ALAN significantly suppressed its activity. Males were more active than females under all experimental treatments. The marked changes in activity under ALAN is of particular concern since global change in combination with urbanization can lead to a change in vegetation density and composition that will decrease the number of suitable microhabitats and expose small mammals to novel habitat changes. We suggest that the single-striped mice could become vulnerable because of urbanization, leading to impacts on its ecosystem broadly.

Lasting effects of avian‐frugivore interactions on seed dispersal and seedling establishment

Abstract The consequences of plant–animal interactions often transcend the mere encounter stage, as those encounters are followed by a chain of subsequent stages on the plant's reproductive cycle that ultimately determine fitness. Yet, the dissemination and recruitment stages of animal‐mediated seed dispersal are seldom analysed jointly, hindering a full understanding of the ecology of seed dispersal. We analyse the dispersal and recruitment of a fleshy‐fruited plant (Pistacia lentiscus), from fruit production to seedling survival up to their second year. We link early reproductive investment of individual plants to seedling recruitment and explore the role played by seed viability, the coterie of frugivores and microhabitat seed deposition. The proportion of viable seeds was generally low (mean = 34%) but highly variable among individual plants (range: 0%–95%). Seed viability did not seem to have a direct effect on individual plant's recruitment. We recorded 28 bird species feeding on P. lentiscus fruits or seeds. Their contribution to plant recruitment was mainly determined by their intensity of fruit consumption and probability to disperse viable seeds. Most frugivores presented non‐random microhabitat preferences, delivering uneven seed contributions to different sites. Post‐dispersal seed predation by rodents was the most limiting phase in P. lentiscus recruitment. Yet, microhabitats showing the lowest predation rates received the lowest seed rain. Hence, we found a decoupling of the dissemination and recruitment stages: most seeds do not arrive at the most suitable microhabitats. We estimate P. lentiscus plants need to produce c. 5 × 105 fruits to recruit a single seedling that survives to its second summer in our study site. Its success as a prevalent species in Mediterranean lowland landscapes relies on its high fecundity and thorough fruit removal and dispersal by a diversified frugivore assemblage, which compensates for the high seed unviability characteristic of this genus. Synthesis: Measuring the delayed, post‐dispersal outcomes of animal frugivory interactions may overturn inferences based on consumption observations only. Seed rain patterns are often decoupled from microhabitats' suitability for seedling recruitment. Hence, more integrative studies that encompass the entire plant reproductive cycle (from fruit production to seedling recruitment) are needed to fully understand frugivores' lasting contribution to plant regeneration in natural populations.

Population assessment of the Endangered Forty-spotted Pardalote Pardalotus quadragintus on Maria Island, Tasmania

The Forty-spotted Pardalote Pardalotus quadragintus is one of the smallest birds in Australia and is endemic to Tasmania, where it occurs only in forest or woodland containing White Gum Eucalyptus viminalis. It is listed as Endangered under the Tasmanian Threatened Species Protection Act 1995 and Commonwealth Environment Protection and Biodiversity Conservation Act 1999. A habitat-stratified survey of Forty-spotted Pardalotes on Maria Island, off the eastern coast of Tasmania, was undertaken in August 2023 to provide a robust estimate of the population. Initial stratification using available vegetation mapping overestimated the availability of suitable habitat based on survey-site habitat evaluations. Forty-spotted Pardalotes were detected at 14 of 74 survey sites, with all detections being at sites where White Gum was the main tree species present. Their mean density was 1.66 birds per hectare, with an estimated total population of 847 birds (CV 0.38, confidence intervals 404–1776 birds). This estimate is consistent with previous uncorrected count-based estimates, although comparisons with historical counts are highly subjective given the substantial methodological differences. Only ~5% of Maria Island supports the preferred habitat for this species and further research on the requirements for, and abundance of, suitable microhabitat is recommended to further refine population estimates and guide conservation management actions.

Micro-habitat features determine oviposition site selection in High Brown and Dark Green Fritillaries

The survival of butterfly populations depends on successful oviposition strategies. The limited mobility of early life stages requires females to select sites that reflect larval requirements. However, as land use and climate changes are altering habitat conditions and micro-climate, some species may adapt ovipositing strategies and flourish while others, with narrow niche requirements, may be unable to respond. Oviposition site selection and micro-habitat niche is examined for two closely related butterfly species—the specialist High Brown Fritillary (Fabriciana adippe) and relative generalist Dark Green Fritillary (Speyeria aglaja) through field observations of egg-laying females and analysis of micro-habitat characteristics. A total of 104 oviposition behaviour observations across both species were recorded in 69 1 m2 quadrats, with the habitat characteristics compared to randomly selected quadrats in the same area. Results show that higher host plant density was a positively significant factor for oviposition site selection only for the High Brown Fritillary. Moreover, the cover of live Bracken (Pteridium aquilinum) and grass were important for site selection in both species, with High Brown Fritillaries tolerating less live Bracken and grass cover than Dark Green Fritillaries. This confirms the more specific requirements and narrower micro-habitat niche of the High Brown Fritillary, which appears to be more sensitive to micro-habitat cooling.Implications for insect conservationThe management of Bracken mosaic habitats for these two species should aim to supress grass growth and maintain Bracken density within limits, by opening the Bracken canopy on a rotation through grazing or manual cutting, ensuring a continuous supply of suitable micro-habitat.

Opposite effects of host tree species on the realised niche of Dicranum viride – A model species belonging to the group of endangered epiphytes

Functional diversity is widely recognised as the key to understanding the role of ecological mechanisms in shaping the patterns of species co-existence across different environmental gradients. Despite research in this area, there is a considerable knowledge gap on the ecological mechanisms that shape the composition of bryophyte communities, especially those at risk. One of the most endangered group of species are usually woodland specialist bryophytes, therefore, understanding the factors determining their occurrence should be a priority. One of the model species belonging to this group is Dicranum viride, a target species of international conservation importance, and of particular interest for forest managers responsible for forest ecosystems protection.We examined the effect of the tree phorophyte species on the realised niche of D. viride in the temperate forest ecosystems. The specific tree species that D. viride inhabits greatly influences its realised niche. Both phorophyte species we examined, i.e. Fagus sylvatica and Carpinus betulus, can sustain the presence of D. viride, but the key determinant is the availability of suitable microhabitats, such as specific combinations of bryophyte species within bark irregularities. Our findings indicate that even in regions where the effects of forest management are noticeable, the preservation of trees with diverse microhabitats facilitate the existence of rare moss species with D. viride as an example.As a moss with a narrow ecological amplitude, D. viride occurrence patterns can be used as a tool in monitoring studies and for improving forest management strategies aimed at harmonising wood production with the conservation of biodiversity and ecosystem functioning. As a result, this information can be significant for conservation strategies, as it highlights the importance of identifying and preserving certain tree species to protect both particular epiphyte communities and individual target species.

Tree canopy enhances Collembola functional richness and diversity across typical habitats of the Gorongosa National Park (Mozambique)

The role of tree canopies in protecting soil functional diversity is essential for ecosystems threatened by the longer lasting periods of drought, which are predicted to increase in the southern afro-tropical region. Nonetheless, biodiversity inventories of soil mesofauna are scarce in afro-tropical ecosystems, even in emblematic and well-studied protected areas, such as the Gorongosa National Park (GNP). Understanding the interrelationships between tree canopies and soil fauna functional diversity can provide insightful information for future adaptive management to protect wildlife and ecosystem services in the GNP, in the context of climate change. Here we assessed collembolan functional type richness and functional diversity in the dry period and during the rainfall across major GNP habitat types: miombo forests, mixed forests, and open savanna/floodplains. Besides the significant positive influence of rainfall, habitat types also influenced functional type’ richness and diversity of collembolan life-forms. Environmental gradients across habitat types, namely the area of tree canopy cover and its indirect effect on soil local conditions (pH and nutrient availability), explained collembolan functional parameters. Calcium concentrations and soil alkalinity significantly enhanced collembolan functional type richness and functional diversity, respectively. Collembola survival across GNP habitats depended on the canopy buffering in the dry sampling period. These results highlight the key role of tree canopies in creating suitable microhabitat conditions supporting soil functional diversity and the sustainability of soil processes and ecosystem services in GNP.

Movement patterns in Florida pine snakes are shaped by landscape heterogeneity, ambient air temperature and reproductive ethology

Abstract Although variation in space use has been investigated extensively in terrestrial vertebrates, there have been recent criticisms that there are more data for mammals than reptiles. This may be an important consideration because the factors that shape movement patterns in reptiles could differ from those of mammals leading to misleading generalizations if data for mammals are extrapolated to reptiles. Here, we quantified the relationships between space use size, movement velocity and turn angle in 24 adult Florida pine snakes (Pituophis melanoleucus mugitus). We tested the effects of site, season, sex, the distribution of vegetation cover, and ambient air temperature on movement patterns. We also assessed the use of underground refugia across seasons, because underground refugia are thought to play an important role in the ecology and evolution of Florida pine snakes. Our results indicate that the movement patterns that shape space use variation in Florida pine snakes are affected by the heterogeneity of suitable microhabitats across landscapes, ambient air temperature and reproductive ethology. This study strengthens our collective understanding of movement patterns in Florida pine snakes and contributes to a growing body of knowledge of the movement ecology of snakes. Broadly, our results highlight general differences in the movement ecologies of mammals and Florida pine snakes that could potentially extend to our understanding of other ectothermic lineages, being predictably linked to metabolic theory.

A simulation model of functional habitat connectivity demonstrates the importance of species establishment in older forests

Fragmented natural habitats, such as old-growth forests, have been often considered island-like systems. However, whereas the isolation of real islands is mostly a function of their spatial arrangement, the biodiversity of old-growth forest patches is also affected by how well the surrounding suboptimal habitats, such as younger forests, can support the functional connectivity between the old-forest fragments. The latter topic remains largely unclear due to the lack of mechanistic knowledge about the processes behind species’ affinity for old forest. Although in animal ecology, functional connectivity has often been investigated with mechanistic agent-based models, these have rarely been applied for passively dispersing organism groups. We used a pattern-oriented modeling approach by combining a spatially explicit agent-based model and an empirical biodiversity dataset of Estonian old-growth nemoral forest sites, to study how forests of different ages between the old-forest fragments are exploited by different passively or slowly dispersing functional groups. We found that the establishment of ground layer vegetation, epiphytes, ectomycorrhizal and pathogenic fungi is significantly restricted in the younger forests, whereas no clear difference between forest-age classes emerged for survival. Our results thus suggest that establishment, not survival, is the main process behind the species’ affinity for old forest, concurring with studies that have demonstrated the importance of suitable microhabitat availability in older forests. We conclude that young secondary forests do not support the connectivity – and consequently, biodiversity – of many old-forest specific groups.

Study of terrestrial diatoms in corticolous assemblages from deciduous trees in Central Europe with descriptions of two new Luticola D.G.Mann taxa.

Although many studies have examined the algae associated with various habitats in tree trunks, the diatoms in these environments are still poorly studied. Studies of corticolous algae mainly focus on green algae and cyanobacteria, which are usually immediately visible, while diatoms are mostly overlooked or not reported. During the research, 143 species of diatoms were identified, including two new representatives of the genus Luticola: L.bryophilasp. nov. with relatively large central area and short distal raphe endings and L.confusasp. nov. characterized by the presence of small depressions on central raphe endings. Both are described herein based on light and scanning electron microscopy observations and compared to similar taxa based on literature data. Basic morphological data for almost all the diatom taxa are noted, and their habitat requirements, and photographic documentation are also presented. The present research showed that the occurrence of diatom assemblages on tree trunks is influenced by various factors like host tree species, the area where the host tree grows, and the availability of suitable microhabitats within the trunk. However, the species composition of this assemblages depends mainly on the tree species.

Seasonal and diurnal patterns of littoral microhabitat use by fish in gravel pit lakes, with special reference to supplemented deadwood brush piles

The habitat quality of the littoral zone is of key importance for almost all lentic fish species. In anthropogenically created gravel pit lakes, the littoral zone is often structurally homogenized with limited fish habitats. We supplemented deadwood brush piles in the littoral zone of eight gravel pit lakes and investigated the diurnal and seasonal use of this and other typical microhabitats by six dominant fish species. Shoreline habitats were sampled using point abundance electrofishing during day and night in all four seasons, and patterns of fish abundance were compared amongst unstructured littoral habitats, emerged macrophytes and brush piles. We caught a total of 14,458 specimens from 15 species in the gravel pit lakes. Complex shoreline structures were used by all fish species that we examined, especially during daytime, whilst the use of unstructured habitats was highest during night. The newly added brush piles constituted suitable microhabitats for selected fish species, perch (Perca fluviatilis), roach (Rutilus rutilus) and pike (Esox lucius), particularly during winter. Supplemented deadwood provides suitable fish habitat in gravel pit lakes and may to some degree compensate for the loss of submerged macrophytes in winter by offering refuge and foraging habitat for selected fish species.

Resampling alpine herbarium records reveals changes in plant traits over space and time

Abstract Climate warming causes upward shifts in plant species distributions, resulting in an influx of species from lower elevations into alpine plant communities. Plant functional trait changes along elevation gradients and over time may reflect these changing conditions. Intraspecific trait variation measured from herbarium records offers a way to observe such changes in trait values over time. We selected four species: Poa alpina and Polygonum viviparum found in alpine grasslands, and Cardamine resedifolia and Ranunculus glacialis found in high‐alpine to subnival scree habitats. We measured several functional traits from (i) herbarium records collected between 1880 and 1950 and from (ii) individuals resampled in 2014 along an elevation gradient covering >1500 m within the same study region in the Swiss Alps. By comparing (i) against (ii) for each species separately, we analysed temporal changes in the distribution of traits along the studied elevation gradient. After a century of climate warming, the change in the relationship linking plant functional traits with elevation was species dependent. Size‐related and reproductive functional trait values for P. viviparum increased over time, increasing at lower, but not higher elevations. Poa alpina's size‐related traits increased consistently with time along the elevation gradient. Most of C. resedifolia's size‐related and flowering traits decreased over time at lower elevations and converged at higher elevations. Finally, R. glacialis traits did not respond to time alone—reproductive traits decreased over time at lower, and increased at higher elevations, reversing their historical trait distributions. The negative trend for vegetative trait values with elevation did not change over time, however. In 2014, at lower elevations, all species mainly occurred on their typical microhabitat types, but occurrence on other microhabitats increased with elevation for all species. Synthesis: Contrasting temporal changes in the distribution of growth and reproductive trait values between alpine grassland and alpine‐subnival scree species, especially at lower elevations, suggest that climate warming effects vary among species. Additionally, species' physiological constraints and availability of suitable microhabitats may further impact species' distribution changes. Further warming may confine the distribution of high‐alpine plant species to even higher elevations, or microclimates currently difficult to colonise by lower‐alpine species.

Microclimate species distribution models estimate lower levels of climate-related habitat loss for salamanders

Species distribution models (SDMs) largely rely on free-air temperatures at coarse spatial resolutions to predict habitat suitability, potentially overlooking important microhabitat. Integrating microclimate data into SDMs may improve predictions of organismal responses to climate change and support targeting of conservation assets at biologically relevant scales, especially for small, dispersal-limited species vulnerable to climate-change-induced range loss. We integrated microclimate data that account for the buffering effects of forest vegetation into SDMs at a very high spatial resolution (3 m2) for three plethodontid salamander species in Great Smoky Mountains National Park (North Carolina and Tennessee). Microclimate SDMs were used to characterize potential changes to future plethodontid habitat, including habitat suitability and habitat spatial patterns. Additionally, we evaluated spatial discrepancies between predictions of habitat suitability developed with microclimate and coarse-resolution, free-air climate data. Microclimate SDMs indicated substantial losses to plethodontid ranges and highly suitable habitat by mid-century, but at much more conservative levels than coarse-resolution models. Coarse-resolution SDMs generally estimated higher mid-century losses to plethodontid habitat compared to microclimate models and consistently undervalued areas containing highly suitable microhabitat. Furthermore, microclimate SDMs revealed potential areas of future gain in highly suitable habitat within current species’ ranges, which may serve as climatic microrefugia. Taken together, this study highlights the need to develop microclimate SDMs that account for vegetation and its biophysical effects on near-surface temperatures. As microclimate datasets become increasingly available across the world, their integration into correlative and mechanistic SDMs will be imperative for accurately estimating organismal responses to climate change and helping environmental managers tasked with spatially prioritizing conservation assets.

Ground‐based vegetation descriptions and remote sensing as complementary methods describing habitat requirements of a frugivorous primate in northern Madagascar: implications for forest restoration

AbstractNon‐human primate species are threatened worldwide. Their population declines go along with the loss of ecological functions such as seed dispersal that plays a crucial role in plant regeneration. Restoring essential habitat structures could thus not only protect primates, but also facilitate forest regeneration. We used classical vegetation description on the ground and a remote sensing analysis to describe habitat use of crowned lemurs (Eulemur coronatus), a seed‐dispersing primate endemic to northern Madagascar. Our aim was to find vegetation characteristics important for lemurs that might be targeted in a restoration approach. For this, we applied both methods in differently degraded forest types. Both classical vegetation description and remote sensing analysis were able to distinguish these forest types. The habitat use of our two study groups was associated consistently with vegetation structures measured on a small scale such as tree height and density of thick trees. In contrast, vegetation productivity and water content derived from satellite imagery on a larger scale could not consistently explain habitat use of lemurs. Thus, measurements on the ground can identify suitable microhabitats that do not show on the satellite imagery scale. These microhabitats might be very important conservation elements to create buffer zones and corridors. Further, they might attract seed‐dispersing species into degraded areas targeted for forest restoration, acting as natural regeneration nuclei. The potential of these microhabitats for conservation would not be recognized when analyses were based solely on landscape analyses on large scales.

Significance of seed dispersal by the largest frugivore for large-diaspore trees

How do large-bodied frugivores contribute to seed dispersal of large-diaspore plants? This study examined seed dispersal effectiveness for two large-diaspore tree species, Astrotrichilia asterotricha (AA) and Abrahamia deflexa (AD), in a Madagascan forest. I evaluated fruit removal rates through focal tree observations and factors affecting seedling recruitment up to the 2-year-old seedling stage. I confirmed brown lemur (Eulemur fulvus) as the sole disperser, removing 58.8% and 26.0% of fruits produced by AA and AD. Brown lemurs frequently visited large-crowned AA trees with high density of fallen fruits and more adjacent fruiting trees during seasons with low fruit diversity. Most AA seedlings were removed by predators, although canopy openness slightly improved seedling establishment. Although AD seeds were severely attacked by predators under mother trees, the seedlings survived under dispersal conditions distant from the mother trees, and with low density of diaspores. AD had a higher cumulative probability from fruit removal to seedling recruitment (6.5%) than AA (1.5%) in the first rainy season. This study clarifies the significance of seed dispersal to tree recruitment strategies, which vary among different combinations of tree species and large frugivores, i.e. quantitative dispersal to reach suitable microhabitats, and qualitative dispersal to escape from dangerous zones near mother trees.

Plant species-dependent transmission of Escherichia coli O157:H7 from the spermosphere to cotyledons and first leaves.

The colonization of six edible plant species: alfalfa, broccoli, coriander, lettuce, parsley and rocket, by the human pathogen Shigatoxigenic Escherichia coli was investigated following two modes of artificial inoculation of seeds, by soaking or watering. The frequency and extent of colonization of cotyledons depended on the mode of inoculation, with three, rapidly germinating species being successfully colonized after overnight soaking, but slower germinating species requiring prolonged exposure to bacteria by watering of the surrounding growth media. Separate analysis of the cotyledons and leaves from individual plants highlighted that successful colonization of the true leaves was also species dependent. For three species, failure of transfer, or lack of nutrients or suitable microhabitat on the leaf surface resulted in infrequent bacterial colonization. Colonization of leaves was lower and generally in proportion to that in cotyledons, if present. The potential risks associated with consumption of leafy produce are discussed.

Accidental epiphytes: Ecological insights and evolutionary implications

AbstractVascular 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 epiphytes and the initial evolution of epiphytic lineages. Even though accidental epiphytes have been mentioned in the literature for more than a century, they have been neglected in most epiphyte studies. Only recently has accidental epiphytism been investigated more thoroughly. Therefore, the aim of this article is to provide a comprehensive review of the ecological basis and evolutionary relevance of this common but largely neglected phenomenon and to highlight open questions and promising research directions. Our central statement—that any species has the potential to grow epiphytically given the availability of suitable microhabitats and successful dispersal—is backed up by a compilation of observations of accidental epiphytes from numerous ecosystems with diverse climates, even including semiarid Mediterranean ones. A variety of arboreal microhabitats and environmental conditions conform to the ecological niche of typical terrestrial species, with the availability of such microhabitats depending on the interaction of local climate conditions, host tree age, and host species identity. Whenever suitable microhabitats are available in tree crowns, accidental epiphytism is limited primarily by dispersal. In an evolutionary context, the conquest of forest canopy represents an ecological opportunity where accidental epiphytes act as links between terrestrial and epiphytic life forms. We discuss two fundamental scenarios with sympatric speciation, selective pressure, autopolyploidy, and allopatric speciation as underlying mechanisms in the transition from terrestrial to epiphytic growth. In conclusion, we argue that accidental epiphytism is a substrate and dispersal‐dependent phenomenon and that, both from an individual perspective and an evolutionary perspective, epiphytism reflects the occupation of suitable but previously unexploited arboreal microhabitats. Acknowledging the fundamental principles that plant growth is opportunistic and that dispersal is a stochastic process can decisively improve our understanding of species distributions and other ecological patterns, as in the case of accidental epiphytism.

Seed fate in ant‐mediated dispersal: Seed dispersal effectiveness in the Ectatomma ruidum (Formicidae)—Zanthoxylum ekmanii (Rutaceae) system

AbstractPlants are often dispersal limited relying on passive or active agents to find suitable microhabitats for germination. Seeds of pioneer tree species, for example, require light gaps for growth but have short median dispersal distances and often do not provide a food reward to encourage animal dispersal. Zanthoxylum ekmanii seeds are frequently moved by ants but evaluating the effectiveness of ant‐mediated seed removal requires knowledge of the species moving the seeds, how far they are moved, and the deposition site. To assess the effectiveness of ants as seed dispersers of Z. ekmanii, we utilized the seed dispersal effectiveness framework. We tracked the movement of seeds from caches on the forest floor, revealing that foragers of Ectatomma ruidum moved 32.8% of seeds an average first distance of 99.8 cm with 68.3% of those seeds taken into a colony. The quality of deposition location was assessed using a seedling emergence study where freshly germinated seeds were buried at different depths. Seedlings were primarily able to emerge from the shallowest depths. Wax castings of E. ruidum colonies demonstrated that seeds brought into the colony were deposited in chambers that had larvae present and experienced more damage than seeds unhandled by ants. Foragers, however, did not have a strong enough bite force to rupture Z. ekmanii seeds likely because their muscle morphology is not structured to maximize force generation. Overall, E. ruidum may help fine tune deposition location, incorporating seeds into the topsoil, though few seeds will likely emerge if soil bioturbation is low.Abstract in Spanish is available with online material