Community Ecology of Epiphytes and other Arboreal Plants in the New Zealand Eco-region

<p><b>Epiphytes and other structurally-dependent plants have a spatial ecology and community structure intrinsically linked to that of the host trees in the forest, unlike fully terrestrial plants. Understanding of the ecological implications of this from a theoretical perspective is in its infancy. New Zealand’s south temperate rainforest, whilst not as species rich as tropical forests, hosts one of the richest temperate epiphyte floras. Our understanding of the ecological processes structuring the epiphyte communities of New Zealand forests is however lacking. Here, I present four key studies seeking to add to our knowledge of epiphyte community structure, host specificity and spatial ecology in the New Zealand eco-region.</b></p> <p>First, I tested if seed size determined the likelihood of woody plant species occurring epiphytically on tree ferns (their arboreality) – Chapter 2. Arboreality was negatively related to seed size, with only smaller-seeded species commonly occurring on tree ferns. However, the effect of seed size reduced in later life history stages, as expected. These small-seeded species, most notably Weinmannia racemosa, appear to be utilising an alternative recruitment strategy by establishing epiphytically on the tree fern trunks.</p> <p>Second, on Cyathea dealbata host tree ferns, I tested patterns of species accumulation, metacommunity network structure, and differences in vertical stratification (Chapter 3). Epiphytes and climbers followed a species accumulation model of succession between tree ferns of different sizes and between older and younger portions of the tree fern. The metacommunity network showed patterns of species co-occurrence and nestedness consistent with null expectations. Epiphytes of different habits and different dispersal syndromes show different vertical profiles of occurrence, with bird-dispersed species occurring more often near the top of the tree fern than other taxa.</p> <p>To understand an unusual pattern in epiphyte between-host structuring, I quantified the relationship between epiphytic plant and sooty mould assemblages in New Zealand montane beech forest (Chapter 4). Due to the presence of host specific scale insects, the sooty mould was limited to two of three co-dominant canopy tree species. On these two host species, epiphyte richness was significantly reduced. The host size-richness relationship in these two species was also removed, with species composition significantly altered compared to the mould free host species. My results are consistent with the sooty mould amensally excluding the epiphytes and it can be considered as a part of a keystone species complex (with the host beeches and scale insects). This produces a strong pattern of parallel host specificity otherwise not seen in epiphyte assemblages.</p> <p>Lastly, I compared the differences in spatial niche and host species diversity between three arboreal plants, with divergent ecophysiology, on Lord Howe Island (Chapter 5). These focal species were a dwarf mistletoe, an epiphytic orchid and an epiphytic fern. The mistletoe was restricted to thinner branches, and had a significantly different niche to both epiphyte taxa. The host diversity of the mistletoe and orchid both differed significantly from null model expectations. However, the epiphytic fern (Platycerium bifurcatum) had a host diversity consistent with null expectations.</p> <p>Taken together, these studies increase our understanding of epiphyte community assembly in New Zealand and provide a platform to encourage further work in this field. They also provide results that expand understanding of spatial patterns between host and up vertical clines.</p>

Community Ecology of Epiphytes and other Arboreal Plants in the New Zealand Eco-region

<p><b>Epiphytes and other structurally-dependent plants have a spatial ecology and community structure intrinsically linked to that of the host trees in the forest, unlike fully terrestrial plants. Understanding of the ecological implications of this from a theoretical perspective is in its infancy. New Zealand’s south temperate rainforest, whilst not as species rich as tropical forests, hosts one of the richest temperate epiphyte floras. Our understanding of the ecological processes structuring the epiphyte communities of New Zealand forests is however lacking. Here, I present four key studies seeking to add to our knowledge of epiphyte community structure, host specificity and spatial ecology in the New Zealand eco-region.</b></p> <p>First, I tested if seed size determined the likelihood of woody plant species occurring epiphytically on tree ferns (their arboreality) – Chapter 2. Arboreality was negatively related to seed size, with only smaller-seeded species commonly occurring on tree ferns. However, the effect of seed size reduced in later life history stages, as expected. These small-seeded species, most notably Weinmannia racemosa, appear to be utilising an alternative recruitment strategy by establishing epiphytically on the tree fern trunks.</p> <p>Second, on Cyathea dealbata host tree ferns, I tested patterns of species accumulation, metacommunity network structure, and differences in vertical stratification (Chapter 3). Epiphytes and climbers followed a species accumulation model of succession between tree ferns of different sizes and between older and younger portions of the tree fern. The metacommunity network showed patterns of species co-occurrence and nestedness consistent with null expectations. Epiphytes of different habits and different dispersal syndromes show different vertical profiles of occurrence, with bird-dispersed species occurring more often near the top of the tree fern than other taxa.</p> <p>To understand an unusual pattern in epiphyte between-host structuring, I quantified the relationship between epiphytic plant and sooty mould assemblages in New Zealand montane beech forest (Chapter 4). Due to the presence of host specific scale insects, the sooty mould was limited to two of three co-dominant canopy tree species. On these two host species, epiphyte richness was significantly reduced. The host size-richness relationship in these two species was also removed, with species composition significantly altered compared to the mould free host species. My results are consistent with the sooty mould amensally excluding the epiphytes and it can be considered as a part of a keystone species complex (with the host beeches and scale insects). This produces a strong pattern of parallel host specificity otherwise not seen in epiphyte assemblages.</p> <p>Lastly, I compared the differences in spatial niche and host species diversity between three arboreal plants, with divergent ecophysiology, on Lord Howe Island (Chapter 5). These focal species were a dwarf mistletoe, an epiphytic orchid and an epiphytic fern. The mistletoe was restricted to thinner branches, and had a significantly different niche to both epiphyte taxa. The host diversity of the mistletoe and orchid both differed significantly from null model expectations. However, the epiphytic fern (Platycerium bifurcatum) had a host diversity consistent with null expectations.</p> <p>Taken together, these studies increase our understanding of epiphyte community assembly in New Zealand and provide a platform to encourage further work in this field. They also provide results that expand understanding of spatial patterns between host and up vertical clines.</p>

Inferring the Potential Geographic Distribution and Reasons for the Endangered Status of the Tree Fern, Sphaeropteris lepifera, in Lingnan, China Using a Small Sample Size

In this study, we investigated suitable habitats for the endangered tree fern, Sphaeropteris lepifera (J. Sm. ex Hook.) R.M. Tryon, based on fieldwork, ecological niche modeling, and regression approaches. We combined these data with the characterization of spore germination and gametophytic development in the laboratory to assess the reasons why S. lepifera is endangered and to propose a conservation strategy that focuses on suitable sites for reintroduction and accounts for the ecology and biphasic life cycle of the species. Our methods represent an integration of process- and correlation-based approaches to understanding the distributional patterns of this species, and this combined approach, while uncommonly applied, is a more robust strategy than either approach used in isolation. Our ecological niche models indicated that cold temperature extremes, temperature stability over long- and short-terms, and the seasonality of precipitation were among the most important abiotic environmental factors affecting the distribution of S. lepifera among the variables that we measured. Moreover, distribution of this fern species is also strongly influenced by the timing of development of male and female gametes. Additionally, we observed that slope aspect, specifically south-facing slopes, facilitates more incoming sunlight for mature trees, and simultaneously, provides greater, much-needed shade for fiddleheads on account of the canopy being denser. We believe that our study can provide important guidance on the restoration of S. lepifera in the wild. Specifically, potential restoration areas can be screened for the specific environmental factors that we infer to have a critical impact on the survival of the species.

Composition, community structure, and vertical distribution of epiphytic ferns on Cyathea junghuhniana in Gede-Pangrango National Park, Indonesia

Hasanah U, Hadisunarso, Praptosuwiryo TN. 2021. Composition, community structure, and vertical distribution of epiphytic ferns on Cyathea junghuhniana in Gede-Pangrango National Park, Indonesia. Biodiversitas 22: 4968-4976. Epiphytic ferns are a significant component of tropical forests worldwide and contribute significantly to the high species diversity found in tropical regions. Tree ferns are important phorophytes for the establishment and occurrence of epiphytic fern species in tropical forests. The first detailed description of the diversity and abundance of epiphytic ferns on the tree fern Cyathea junghuhniana (Kunze) Copel. in a natural forest of Indonesia is provided. This study aimed to determine the species composition, richness, abundance, community structure, and vertical distribution of epiphytic ferns growing on the tree fern C. junghuhniana in the mountain forest of Gede-Pangrango National Park, West Java, Indonesia. The 35 tree fern caudices of at least 3 m height were selected by purposive random sampling. Each tree fern was divided into intervals of 1 meter from ground level to a height of three meters, thus obtaining 105 one-meter samples of the epiphytic fern community on tree fern caudices stratified according to height. The Importance Value Index (IVI) was estimated for each species of epiphyte based on the frequency of occurrence on caudices. The 35 tree fern caudices hosted 760 fern epiphytes belonging to 12 species of 9 genera and 6 families. The highest species richness occurred in Polypodiaceae. The species with the highest Importance Value Index (IVI = 1.24 %) was Nephrolepis davallioides (Sw.) Kunze, with increasing frequency from bottom to top of the caudex.

Occurrence of some campanian-maastrichtian organic-walled microfossils from Enugu Shale, Anambra Basin, Southeastern nigeria: Implications for age and paleoenvironments

Detailed geological field mapping and sampling of the Enugu Formation in the Anambra Basin has been carried out in order to re-examine the age of sediments and reconstruct their paleoenvironments of deposition. A total of ten (10) outcrop samples of shale were subjected to palynological laboratory examination, using conventional method of acid demineralization and maceration techniques for recovering acid-insoluble organic-walled microfossils from sediments. Two main lithological units were distinguished: - carbonaceous fissile shale and siltstone. A late Campanian - Earliest Maastrichtian age was assigned based on index palynomorphs marker taxa Longapertites marginatus (overwhelming abundance), Monocolpites marginatus, Zlivisporis blanensis, and Echitriporites trianguliformis. The age designation was strengthened by the occurrence of a well-known stratigraphic age-diagnostic organic-walled microplankton Coronifera tubulosa, Senegalinium spp. and Andalusiella polymorpha. Palynomorphs of environmental value include Cyathidites minor, (a tree fern of wet, forested, tropical to temperate regions, usually most developed in mountainous / highland terrains under moist and equable climate); Spinizonocolpites baculatus/echinatus, Longapertites marginatus, Mauritidites crassibaculatus and Moncolpites marginatus, which are palm pollen that inhabit similar brackish water as the mangrove. A non-marine to marginal marine depositional setting has therefore been proposed for the Enugu Formation.

YU-FENG GU, MORIGENGAOWA, RI-HONG JIANG, BAO-DONG LIU & YUE-HONG YAN (2021) Sphaeropteris guangxiensis Y. F. Gu & Y. H. Yan (Cyatheaceae), a new species of tree fern from Southern China. Phytotaxa 518 (1): 69–74.

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Sphaeropteris guangxiensis Y. F. Gu & Y. H. Yan (Cyatheaceae), a new species of tree fern from Southern China

Nearly 103 species of Sphaeropteris are distributed in tropical area, of which three species are indigenous to China. Our previous molecular study of the genus in China showed that there is an undescribed species from Guangxi province which could be originated from natural hybridization. In this study, we carried out further morphological studies on the species of Sphaeropteris in China, and assessed the status of the new species. Here, we described and illustrated the new species as S. guangxiensis Y.F. Gu & Y.H. Yan.

Monilochaetes pteridophytophila (Australiascaceae, Glomerellales), a new fungus from tree fern

During taxonomic and phylogenetic studies of fungi on pteridophytes in Thailand, Monilochaetes pteridophytophila sp. nov. was collected from the frond stalks of a tree fern (Alsophila costularis, Cyatheaceae). The new species is introduced, based on evidence from morphology and phylogenetic analyses of a concatenated dataset of LSU, ITS, SSU and RPB2 sequences. Monilochaetes pteridophytophila differs from extant species of Monilochaetes in having darker conidiophores with fewer septae (1–4-septate). Monilochaetes pteridophytophila forms a distinct clade, basal from other species of Monilochaetes in Australiascaceae. A detailed description and illustrations of the new species are provided. We also provided a synopsis of accepted species of Monilochaetes.