Regeneration patterns and persistence of the fog-dependent Fray Jorge forest in semiarid Chile during the past two centuries

The persistence of rainforest patches at Fray Jorge National Park (FJNP) in semiarid Chile (30°40′S), a region receiving approximately 147 mm of annual rainfall, has been a source of concern among forest managers. These forests are likely dependent on water inputs from oceanic fog and their persistence seems uncertain in the face of climate change. Here, we assessed tree radial growth and establishment during the last two centuries and their relation to trends in climate and canopy disturbance. Such evaluation is critical to understanding the dynamics of these semiarid ecosystems in response to climate change. We analyzed forest structure of six forest patches (0.2–22 ha) in FJNP based on sampling within 0.1 ha permanent plots. For the main canopy species, the endemic Aextoxicon punctatum (Aextoxicaceae), we used tree‐ring analysis to assess establishment periods, tree ages, growing trends and their relation to El Niño Southern Oscillation (ENSO), rainfall, and disturbance. The population dynamics of A. punctatum can be described by a continuous regeneration mode. Regeneration of A. punctatum was sensitive to different canopy structures. Growth release patterns suggest the absence of large scale human impact. Radial growth and establishment of A. punctatum were weakly correlated with rainfall and ENSO. If water limits forests patch persistence, patches are likely dependent on the combination of fog and rain water inputs. Forest patches have regenerated continuously for at least 250 years, despite large fluctuations in rainfall driven by ENSO and a regional decline in rainfall during the last century. Because of the positive influence on fog interception, forest structure should be preserved under any future climate scenario. Future research in FJNP should prioritize quantifying the long‐term trends of fog water deposition on forests patches. Fog modeling is crucial for understanding the interplay among physical drivers of water inputs under climate change.     

Gap-phase dynamics and coexistence of a long-lived pioneer and shade-tolerant tree species in the canopy of an old-growth coastal temperate rain forest of Chiloé Island, Chile

Aim A major question with regard to the ecology of temperate rain forests in south‐central Chile is how pioneer and shade‐tolerant tree species coexist in old‐growth forests. We explored the correspondence between tree regeneration dynamics and life‐history traits to explain the coexistence of these two functional types in stands apparently representing a non‐equilibrium mixture. Location This study was conducted in northern Chiloé Island, Chile (41.6° S, 73.9° W) in a temperate coastal rain forest with no evidence of stand disruption by human impact. Methods We assessed stand structure by sampling all stems within two 50 × 20 m and four 5 × 100 m plots. A 600‐m long transect, with 20 uniformly spaced sampling points, was used to quantify seedling and sapling densities, obtain increment cores, and randomly select 10 tree‐fall gaps. We used tree‐ring analysis to assess establishment periods and to relate the influences of disturbances to the regeneration dynamics of the main canopy species. Results Canopy emergent tree species were the long‐lived pioneer Eucryphia cordifolia and the shade‐tolerant Aextoxicon punctatum. Shade‐tolerant species such as Laureliopsis philippiana and several species of Myrtaceae occupied the main canopy. The stem diameter distribution for E. cordifolia was distinctly unimodal, while for A. punctatum it was multi‐modal, with all age classes represented. Myrtaceae accounted for most of the small trees. Most tree seedlings and saplings occurred beneath canopy gaps. Based on tree‐ring counts, the largest individuals of A. punctatum and E. cordifolia had minimum ages estimated to be > 350 years and > 286 years, respectively. Shade‐tolerant Myrtaceae species and L. philippiana had shorter life spans (< 200 years). Most growth releases, regardless of tree species, were moderate and have occurred continuously since 1750. Main conclusions We suggest that this coastal forest has remained largely free of stand‐disrupting disturbances for at least 450 years, without substantial changes in canopy composition. Release patterns are consistent with this hypothesis and suggest that the disturbance regime is dominated by individual tree‐fall gaps, with sporadic multiple tree falls. Long life spans, maximum height and differences in shade tolerance provide a basis for understanding the long‐term coexistence of pioneer and shade‐tolerant tree species in this coastal, old‐growth rain forest, despite the rarity of major disturbances.     

Shrub facilitation drives tree establishment in a semiarid fog‐dependent ecosystem

Questions

The exceptional occurrence of tall rain forest patches on foggy coastal mountaintops, surrounded by extensive xerophytic shrublands, suggests an important role of plant–plant interactions in the origin and persistence of these patches in semi‐arid Chile. We asked whether facilitation by shrubs can explain the growth and survival of rain forest tree species, and whether shrub effects depend on the identity of the shrub species itself, the drought tolerance of the tree species and the position of shrubs in regard to wind direction.

Location

Open area–shrubland–forest matrix, Fray Jorge Forest National Park, Chile.

Methods

We recorded survival after 12 years of a ~3600 tree saplings plantation (originally ~30‐cm tall individuals) of Aextoxicon punctatum, Myrceugenia correifolia and Drimys winteri placed outside forests, beneath the shrub Baccharis vernalis, and in open (shrub‐free) areas. We assessed the effects of neighbouring shrubs and soil humidity on survival and growth along a gradient related to the direction of fog movement.

Results

B. vernalis had a clear facilitative effect on tree establishment and survival since, after ~12 years, saplings only survived beneath the shrub canopy. Long‐term survival strongly depended on tree species identity, drought tolerance and position along the soil moisture gradient, with higher survival of A. punctatum (>35%) and M. correifolia (>14%) at sites on wind‐ and fog‐exposed shrubland areas. Sites occupied by the shrub Aristeguietia salvia were unsuitable for trees, presumably due to drier conditions than under B. vernalis.

Conclusions

Interactions between shrubs and fog‐dependent tree species in dry areas revealed a strong, long‐lasting facilitation effect on planted tree's survival and growth. Shrubs acted as benefactors, providing sites suitable for tree growth. Sapling mortality in the shrubland interior was caused by lower soil moisture, the consequence of lower fog loads in the air and thus insufficient facilitation. While B. vernalis was a key ecosystem engineer (nurse) and intercepted fog water that dripped to trees planted underneath, drier sites with A. salvia were unsuitable for trees. Consequently, nurse effects related to water input are strongly site and species specific, with facilitation by shrubs providing a plausible explanation for the initiation of forest patches in this semi‐arid landscape.     

Diverging drought-tolerance strategies explain tree species distribution along a fog-dependent moisture gradient in a temperate rain forest

The study of functional traits and physiological mechanisms determining species’ drought tolerance is important for the prediction of their responses to climatic change. Fog-dependent forest patches in semiarid regions are a good study system with which to gain an understanding of species’ responses to increasing aridity and patch fragmentation. Here we measured leaf and hydraulic traits for three dominant species with contrasting distributions within patches in relict, fog-dependent forests in semiarid Chile. In addition, we assessed pressure–volume curve parameters in trees growing at a dry leeward edge and wet patch core. We predicted species would display contrasting suites of traits according to local water availability: from one end favoring water conservation and reducing cavitation risk, and from the opposite end favoring photosynthetic and hydraulic efficiency. Consistent with our hypothesis, we identified a continuum of water use strategies explaining species distribution along a small-scale moisture gradient. Drimys winteri, a tree restricted to the humid core, showed traits allowing efficient water transport and high carbon gain; in contrast, Myrceugenia correifolia, a tree that occurs in the drier patch edges, exhibited traits promoting water conservation and lower gas exchange rates, as well low water potential at turgor loss point. The most widespread species, Aextoxicon punctatum, showed intermediate trait values. Osmotic compensatory mechanism was detected in M. correifolia, but not in A. punctatum. We show that partitioning of the pronounced soil moisture gradients from patch cores to leeward edges among tree species is driven by differential drought tolerance. Such differences indicate that trees have contrasting abilities to cope with future reductions in soil moisture.     

Effects of herbivory and patch size on tree seedling survivorship in a fog-dependent coastal rainforest in semiarid Chile

The landscape (matrix) surrounding habitat fragments critically affects the biodiversity of those fragments due to biotic interchange and physical effects. However, to date, there have been only a limited number of studies on plant–animal interactions in fragmented landscapes, particularly on how tree seedling herbivory is affected by fragmentation. We have examined this question in a fog-dependent mosaic of rainforest fragments located on coastal mountaintops of semiarid Chile (30°S), where the effects of the surrounding semiarid matrix and forest patch size (0.1–22 ha) on tree seedling survival were simultaneously addressed. The rainforest is strongly dominated by the endemic evergreen tree species Aextoxicon punctatum (Olivillo, approx. 80% of basal area). To assess the magnitudes and causes of Olivillo seedling mortality, we set up a field experiment where 512 tree seedlings of known age were transplanted into four forest fragments of different sizes in four 1.5 × 3-m plots per patch; one-half of each plot was fenced off with chicken wire to exclude small mammals. The plots were monitored for 22 months. Overall, 50% of the plants died during the experiment. The exclusion of small mammals from the plots increased seedling survival by 25%, with the effect being greater in smaller patches where matrix-dwelling herbivores are more abundant. This experiment highlights the important role of the surrounding matrix in affecting the persistence of trees in forest fragments. Because herbivores from the matrix cause greater tree seedling mortality in small patches, their effects must be taken into account in forest conservation–restoration plans.     

A fungal endophyte slows litter decomposition in streams

1. Phyllosphere interactions are known to influence a variety of tree canopy community members, but less frequently have they been shown to affect processes across ecosystem boundaries. Here, we show that a fungal endophyte (Rhytisma punctatum) slows leaf litter decomposition of a dominant riparian tree species (Acer macrophyllum) in an adjacent stream ecosystem. 2. Patches of leaf tissue infected by R. punctatum show significantly slower decomposition compared to both nearby uninfected tissue from the same leaf, and completely uninfected leaves. These reduced rates of decomposition existed despite 50% greater nitrogen in infected tissues and may be driven by slower rates of decomposition for fungal tissues themselves or by endophyte–hyphomycete interactions. 3. Across a temperate forest in the Pacific Northwest, approximately 72% of all A. macrophyllum leaves were infected by R. punctatum. Since R. punctatum infection can influence leaf tissue on entire trees and large quantities of leaf litter at the landscape scale, this infection could potentially result in a mosaic of ‘cold spots’ of litter decomposition and altered nutrient cycling in riparian zones where this infection is prevalent.     

Tree regeneration responses in a lowland Nothofagus-dominated forest after bamboo dieback in South-Central Chile

The bamboo Chusquea quila (Poaceae:Bambuseae) is the most abundant understory species ofNothofagus-dominated forests at low elevations inthe Chilean Lake District. Species of this genus strongly inhibit theestablishment and growth of tree species, especially those of the genusNothofagus. At intervals of many years, this bambooflowerssynchronously and dies, creating large-scale disturbances. The mainobjective of this study was to determine the influence of bamboo dieback ontreeregeneration, especially of shade-intolerant species. The forest studiedis a remnant stand of old-growth forest dominated by emergent individualsof N. obliqua and Eucryphiacordifoliawhich project about 10 m above a main canopy formed byAextoxicon punctatum, Laureliaphilippiana, and Podocarpus saligna. Treeseedlings that established prior to bamboo dieback were recorded in six gapsdensely covered by bamboo. After the dieback event in the early 1990's,recruitment, height growth and survivorship were monitored in four gaps duringtwo growing seasons. After the synchronous mass flowering and death ofChusqueaquila, both reorganization of advance regeneration and new seedlingrecruitment were observed in gaps. The advance regeneration consisted mainly ofthe shade-tolerant species A. punctatum,L. philippiana, and Amomyrtus luma.These species together with E. cordifolia accounted forover 90% of the total individuals in gaps. During the following twoseasons, c. 40% of the advance regeneration either died or was damaged.Root suckers of E. cordifolia and L.philippiana were taller and grew faster than the seedlings of otherspecies. Nothofagus obliqua was unable to establishadvanceregeneration in gaps formerly dominated by bamboo. New recruitment resulted inthe synchronized establishment of treeseedlings, especially less shade-tolerant species such as N.obliqua, Aristotelia chilensis,Rhaphithamnus spinosus, and E.cordifolia. These species recruited into the gaps almost entirelyduring the first season right after the bamboo dieback. However, by the end ofthe second season, these species had a lower density due to a combination oflower recruitment rate, shortened recruitment period, and greater mortalityratecompared to the shade-tolerant species. New bamboo seedlings grew fasterand were more abundant than tree seedlings, except for root suckers (bothnew establishment and advance regeneration) of E.cordifolia which is more likely to successfully recruit into thecanopy. Seedlings of N. obliqua compete poorly with bambooseedlings; its successful recruitment may require bamboo flowering coincidentwith a mast seed year for the tree species.     

Seedling Mortality and Herbivory Damage in Subtropical and Temperate Populations: Testing the Hypothesis of Higher Herbivore Pressure Toward the Tropics

Herbivory rates are generally thought to be higher in tropical than in temperate forests. Nevertheless, tests of this biogeographic prediction by comparing a single plant species across a tropical-temperate range are scarce. Here, we compare herbivore damage between subtropical and temperate populations of the evergreen tree Aextoxicon punctatum (Olivillo), distributed between 30° and 43° S along the Pacific margin of Chile. To assess the impact of herbivory on Olivillo seedlings, we set up 29 experimental plots, 1.5 × 3 m: 16 in forests of Fray Jorge National Park (subtropical latitude), and 13 in Guabún, Chiloé Island (temperate latitude). Half of each plot was fenced around with chicken wire, to exclude small mammals, and the other half was left unfenced. In each half of the plots we planted 16 seedlings of Olivillo in December 2003, with a total of 928 plants. Seedling survival, leaf production and herbivory by invertebrates were monitored over the next 16 mo. Small mammal herbivores killed ca 30 percent of seedlings in both sites. Nevertheless, invertebrate herbivory was greater in the temperate forest, thus contradicting the expected trend of increasing herbivore impact toward the tropics. Seedling growth was greater in subtropical forest suggesting better conditions for tree growth or that higher invertebrate herbivory depressed seedling growth in the temperate forest. Invertebrate herbivory increased toward temperate latitudes while small mammal herbivory was similar in both sites. We suggest that comparison of single species can be useful to test generalizations about latitudinal patterns and allow disentangling factors controlling herbivory patterns across communities.     

Rain Forest Islands in the Chilean Semiarid Region: Fog-dependency, Ecosystem Persistence and Tree Regeneration

Tree presence in semiarid ecosystems is generally constrained by insufficient annual rainfall. However, in semiarid Chile, rainforest patches dominated by Aextoxicon punctatum are unexpectedly found on coastal mountaintops (450–600 m) at 30°S, surrounded by a xerophytic vegetation matrix that receives only 147 mm of annual precipitation. It has been proposed that these forests persist as a result of fog-water inputs. If so, then because fog-water deposition is spatially heterogeneous and shows strong edge effects, the potential environmental gradient created by the direction of fog input should determine forest structure and tree regeneration patterns. To investigate this hypothesis, we measured fog inputs, forest structural attributes (age and size distribution, basal area, and coarse woody debris), and tree regeneration in three different habitats: the windward edges (WE), leeward edges (LE), and the interior (center) of rainforest patches varying in area from 0.2 to 22 ha. Mean fog-water input was estimated from passive collectors over 1 year in WE and LE of patches. Tree regeneration was greater in the WE and forest interior (FI) and decreased toward the LE of patches, following a marked pattern of decline in fog inputs. Older trees and coarse woody debris were concentrated in the FI and LE of patches. Tree regeneration and patch structure appear to be largely controlled by fog-input direction and edge effects. We propose that forest patches may be slowly growing toward the incoming fog edge, while dying at the opposite edge.     

Artenzusammensetzung,lichtgenuß und energiegehalt der krautschicht des Valdivianischen Regenwaldes bei St. Martin

Zusammenfassung Pflanzensoziologische Aufnahmen im Valdivianischen Regenwald bei St. Martin ergaben, daß dieser Wald als eine Variante des Nothofago-Perseetum zu betrachten ist, der sich durch zahlreiches Vorkommen von Aextoxicon punctatum auszeichnet. Nach dem Lebensformenspektrum dominieren die Phanerophyten, an zweiter Stelle stehen die Epiphyten, von denen die Hymenophyllen 30% ausmachen. Die Vielschichtigkeit des Valdivianischen Regenwaldes bedingt sehr unterschiedliche Lichtbedingungen. Nach der Lichtkartierung lassen sich Nertera granadensis, Seneclo cymosus und Chusquea quila als besonders lichtbedürftige Arten, Rhamnus diffusus, Lapageria rosea und Luzuriaga raticans als im Schatten wachsende Arten charakterisieren.Die Stoffgruppenanalyse ergab auffallend hohe Lipoidgehalte der Blätter: dieser hohe Anteil an Lipoiden und ätherischen Ölen dürfte weitgehend für den ebenfalls hohen Brennwert des Valdivianischen Regenwaldes verantwertlich sein, der nach der Analyse von 29 Arten errechnet wurde. Dieser Brennwert liegt welt über dem des tropischen Regenwaldes, stimmt dagegen fast mit demjenigen von Mischwäldern der gemäßlgten Zone überein. Charakteristisch hebt sich der Brennwert verschiedener Wuchsformen voneinander ab, wobei der Kalorienwert von den Gehölzen und Lianen zu den Epiphyten und weiter zur Krautschicht abfällt. Ein Vergleich der Brennwerte von Monocotylen und Dicotylen aus dem Valdivianischen Regenwald mit den entsprechenden Mittelwerten von Pflanzenmaterial anderer Regionen ergibt eine ziemlich gute Übereinstimmung, jedoch bestchen größere Differenzen, wenn sich der Vergieich auf die Brennwerte bestimmter Familien beschränkt.

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Summary Plant sociological mapping in the Valdivian rain forest near St. Martin/Chile led to the conelusion that this forest should be considered as a variant of the Nothofago-Perseetum with a high abundance of Aextoxicon punctatum. The spectrum of life forms shows clear dominance of phanerophytes, followed by epiphytes; 30% of these are Hymenophyllaceae. The multilayered system of strata within the forest causes quite different light conditions. Nertera granadensis, Senecio cymosus and Chusquea quila require optimal illumination; Rhamnus diffusus, Lapageria and Luzuriaga radicans on the contrary are satisfied with low light intensities in shady places.Analysis of the most important components of the leaves showed surprisingly high contents of lipolds; this and the etheric oils must be responsible for the likewise high caloric value of the Valdivian rain forest which was calculated as an average for 29 species. This average caloric value is far above that for tropical rain forest but almost agrees with that for mixed forests of the temperate zone. The fumigation value of various life forms differs characteristically: it declines from woody species (trees and bushes) plus lianes to epiphytes and to herbs. In a taxonomic comparison of caloric values of monocotyledons and dicotyledons the Valdivian rain forest agrees fairly well with the caloric value of plant material from other regions. However there are higher differences if the comparison of caloric values is limited to distinct plant families.

Prof. Dr. H. Walter zum 80. Geburtstag gewidmet.     

Comparative morphology of the electrosensory system of the epaulette shark Hemiscyllium ocellatum and brown-banded bamboo shark Chiloscyllium punctatum

We compared the electrosensory system of two benthic elasmobranchs Hemiscyllium ocellatum and Chiloscyllium punctatum. The distribution of the ampullary pores on the head was similar for both species, with a higher density of pores anteriorly and a lower density posteriorly, although C. punctatum generally possessed larger pores. Ampullary canals of the mandibular cluster were quasi-sinusoidal in H. ocellatum, a shape previously found in benthic rays only, whereas ampullary canals in C. punctatum were of a linear morphology as reported for many shark and ray species previously. The ampullae proper were of the lobular type, as occurs in most galean sharks. Chiloscyllium punctatum had six sensory chambers compared with the five per ampulla in H. ocellatum, which were generally smaller than those of C. punctatum. The sensory epithelium comprised flattened receptor cells, compared with the usual pear-shaped receptor cells encountered in other elasmobranchs and their apically nucleated supportive cells did not protrude markedly into the ampullary lumen, unlike those in benthic rays.     

ONTOGENY AND PALEOECOLOGY OF THE MIDDLE PENNSYLVANIAN ARBORESCENT LYCOPOD BOTHRODENDRON PUNCTATUM,BOTHRODENDRACEAE (WESTERN MIDDLE ANTHRACITE FIELD,SHAMOKIN QUADRANGLE,PENNSYLVANIA)

Study of an in situ Bothrodendron punctatum community in a strip mine in Bear Valley, Shamokin Quadrangle, Pennsylvania, provides new insights into the ontogeny of Middle Pennsylvanian arborescent lycopods and into the ecological and environmental characteristics of lycopod-dominated clastic-swamp communities. Bothrodendron punctatum began growth as a monocaulous stem. The first branches developed when the stem attained a minimum height of 5 m. Lateral branches bore terminal cones and were determinate and deciduous. They grew to a maximum length of 1 m, and became smaller and more closely spaced with increasing stem height. The branch scars were not disrupted by secondary stem growth indicating that the branches stayed attached until the stem attained its determinate growth limit. The plant grew to a height of 25 m. Though B. punctatum is an uncommon component of Euramerican floras, the plant could become locally dominant under favorable environmental and edaphic conditions. The upper canopy was formed by B. punctatum and contained emergents of Lepidodendron aculeatum and a Sigillaria species. The understory contained pteridosperms and rare Calamites. Bothrodendron punctatum seems to have preferred environments transitional between clastic and peat swamp conditions. It was sensitive to local inhomogeneity in microhabitat characteristics, as well as to regional climatic fluctuations (drought stress). Both these variables produce specifically attributable effects on branch size and separation trends.     

Pollination of lark daisy on roadsides declines as traffic speed increases along an Amazonian highway

Ecological disturbances caused by roadways have previously been reported, but traffic speed has not been addressed. We investigate effects of traffic speed on pollination of Centratherum punctatum (Asteraceae) along an Amazonian highway roadside. We hypothesised that frequency of flower visitors, duration of single visits and pollen deposition on stigmas will vary negatively as traffic speed increases. After measuring vehicle velocities, we classified three road sections as low‐, mid‐ and high‐velocity traffic. The main pollinator bee, Augochlora sp., visited C. punctatum inflorescences with decreasing frequency from low‐ to high‐velocity roadside sections, whereas the nectar thief butterflies did the opposite. Duration of single visits by bees and butterflies was shorter, and arrival of pollen on C. punctatum stigmas was lower, in high‐ than in low‐velocity roadside. Air turbulence due to passing vehicles increases with velocity and disturbed the flower visitors. Overall, results support that traffic velocity negatively affects foraging of flower visitors and the pollination of C. punctatum on roadsides.     

In silico and In vitro evaluation of the anti-inflammatory potential of Centratherum punctatum Cass-A

Centratherum punctatum Cass., a herb belonging to the family Asteraceae has been traditionally used as a curative against diverse disorders like inflammation, tumor, depression, and hypertension. Though the medicinal properties of this plant have been attributed to the presence of flavonoids, glucosides, alkaloids, Vitamin C, etc., the molecular constituents of this plant and of the flavonoids that contribute to its medicinal activity have not been explored yet. This work attempts to evaluate the potential of Centratherum punctatum extract as an anti-inflammatory agent. Ethanolic extracts of Centratherum punctatum analyzed by High Performance Thin Layer Chromatography (HPTLC) and Liquid Chromatography–Mass Spectrometry (LC–MS/MS) identified the presence of the flavones kaempferol, glycoside Isorhamnetin-3-O-rutinoside, and kaempferol-3-glucoside. The plant extract exhibited anti-oxidant property as confirmed by DPPH assay and IC₅₀ value of 271.6 μg/mL during inhibition of protein denaturation, 186.8 μg/mL during RBC membrane stabilization, and 278.2 μg/mL for proteinase inhibition. Membrane stabilizing functions of flavones and flavones glycosides validated the anti-inflammatory potential of the extract. In silico evaluation using a rigorous molecular docking protocol with receptors of Cox2, TNF-α, Interleukin 1β convertase, and Histamine H1 predicted high binding affinity of the isoflavones and isoflavone glycosides of Centratherum punctatum Cass. The interactions have also been shown to compare well with that of known drugs valdecoxib through Gln178, His342, and Gly340, desloratadine (through Lys191 and Thr194) and belnacasin (through Asp288 and Gly287) proven to function through the anti-inflammatory pathway. This work establishes the anti-inflammatory potential of Centratherum punctatum Cass. extract as an alternative to existing therapeutic approach to inflammation through a systematic in silico approach supplementing the findings.     

Differences in the stimulation of cyclic electron flow in two tropical ferns under water stress are related to leaf anatomy

Cyclic electron flow (CEF) plays an important role in photoprotection for angiosperms under environmental stresses. However, ferns are more sensitive to drought and their water transport systems are not as efficient as those of angiosperms, it is unclear whether CEF also contributes to photoprotection in these plants. Using Microsorum punctatum and Paraleptochillus decurrens, we studied the electron fluxes through both photosystem I (PSI) and photosystem II (PSII) under water stress and their leaf anatomies. Our goal was to determine if CEF functions in the photoprotection of these ferns and, if so, whether CEF stimulation is related to leaf anatomy. Compared with P. decurrens, M. punctatum had thicker leaves and cuticles and higher water storage capacity, but lower stomatal density and slower rate of water loss. During induced drought, the decrease in leaf water potential (Ψ_leaf) was more pronounced in P. decurrens than in M. punctatum. For both species, the decline in Ψ_leaf was associated with a lower effective PSII quantum yield, photochemical quantum yield of PSI and electron transport rate (ETR), whereas increases were found in the quantum yield of regulated energy dissipation, CEF and CEF/ETR(II) ratio. Values for CEF and the CEF/ETR(II) ratio peaked in M. punctatum at a light intensity of 500–600 µmol m^?2 s^?1 vs only 150–200 µmol m^?2 s^?1 in P. decurrens. Therefore, our results indicate that the stimulation of CEF in tropical ferns contributes to their photoprotection under water stress, and is related to their respective drought tolerance and leaf anatomy.     

Age and growth of the tropical oviparous shark,Chiloscyllium punctatum in Indonesian waters

The brown-banded bamboo shark, Chiloscyllium punctatum, is the most common shark caught in coastal commercial fisheries throughout Southeast Asia, yet there is a lack of the life-history information necessary for reliable stock assessments. The authors estimated growth rates and age at maturity using analysis of growth bands in vertebral centra. They trialled four different techniques to enhance the visibility and improve identification of the putative annual growth bands necessary for age estimation. The authors found that the burn method on whole vertebral centra provided the most readable and consistent results for age analysis. The logistic model was chosen as the best-fit growth model for age estimation of 330 individual C. punctatum from Indonesia. Several age verification methods, including marginal increment ratio and length-frequency analysis, were performed with the support of age validation through the use of calcein-labelled vertebrae from two sharks maintained in captivity. This study found that C. punctatum from Indonesian waters is a fast-growing species that can grow up to 18 cm year⁻¹, reach an estimated maximum total length of 1 m, mature at c. 6.5 years and live for up to 14 years.     

Do plant mites commonly prefer the underside of leaves?

The adaxial (upper) and abaxial (lower) surfaces of a plant leaf provide heterogeneous habitats for small arthropods with different environmental conditions, such as light, humidity, and surface morphology. As for plant mites, some agricultural pest species and their natural enemies have been observed to favor the abaxial leaf surface, which is considered an adaptation to avoid rain or solar ultraviolet radiation. However, whether such a preference for the leaf underside is a common behavioral trait in mites on wild vegetation remains unknown. The authors conducted a 2-year survey on the foliar mite assemblage found on Viburnum erosum var. punctatum, a deciduous shrub on which several mite taxa occur throughout the seasons, and 14 sympatric tree or shrub species in secondary broadleaf-forest sites in Kyoto, west–central Japan. We compared adaxial–abaxial surface distributions of mites among mite taxa, seasons, and morphology of host leaves (presence/absence of hairs and domatia). On V. erosum var. punctatum, seven of 11 distinguished mite taxa were significantly distributed in favor of abaxial leaf surfaces and the trend was seasonally stable, except for Eriophyoidea. Mite assemblages on 15 plant species were significantly biased towards the abaxial leaf surfaces, regardless of surface morphology. Our data suggest that many mite taxa commonly prefer to stay on abaxial leaf surfaces in wild vegetation. Oribatida displayed a relatively neutral distribution, and in Tenuipalpidae, the ratio of eggs collected from the adaxial versus the abaxial side was significantly higher than the ratio of the motile individuals, implying that some mite taxa exploit adaxial leaf surfaces as habitat.     

苹果蓟属,东南亚大陆菊科一新归化属

该文报道了在泰国北部和中国西南部的菊科一个新归化属——苹果蓟属(Centratherum Cass.)。依据所采集的标本,详细描述了该属在东南亚大陆的唯一代表亚种苹果蓟 [Centratherum punctatum Cass. Subsp. fruticosum(S. Vidal)K. Kirkman ex Shih H. Chen, M. J. Wu & S. M. Li],并配以插图。苹果蓟与其所在属的其他种的区别在于该亚种叶片菱形至椭圆形,叶缘具不规则锯齿,先端微尖,总苞片基部硬化,先端无芒。文中还提供了苹果蓟的分布图,并讨论了其可能的传播途径。     

Species composition and aspects of the biology of Orectolobiformes from Indonesian waters

The biological aspects of members of the order Orectolobiformes exploited in Indonesian waters are given. Seven species belonging to five families were recorded in the catches at various landing sites in southern Indonesia. Of these, Chiloscyllium punctatum was the most abundant species landed, contributing >50% of the number of orectolobiforms recorded. The biological data obtained varied greatly between the species listed. The total length (L_T) at maturity for some species, e.g. C. punctatum and Nebrius ferrugineus, varied from that which has been previously recorded for those species in other regions. This highlights the need for regional‐specific biological data for fisheries managers and conservation assessors.     

The toxicity of tributyltin oxide to the wood-boring beetles Lyctus brunneus Steph. and Anobium punctatum (Deg.)

When tributyltin oxide (TBTO) was tested by British Standard 3653 against Lyctus brunneus, 0·5 % solution, equivalent to 0·72 g/m₂ surface application, gave almost complete protection. Tests to BS 3651, using larvae of Anobium punctatum transferred into fully impregnated wood gave toxic limits of 1·39–2·93 kg/m³ TBTO when benzene was used as diluent. The use of white spirit as diluent gave lower toxic limits, probably due to combined toxic action of TBTO and white spirit residues. TBTO appears to have no contact action against the insects tested. Probit analysis of the test with A. punctatum gave an LD 50 of 0·254 kg/m³ and an LD99 of 3 kg/m³. The advantage of treating results by probit analysis rather than by deriving ‘toxic limits’ is discussed.