Mixed Evergreen Forest Research Articles

Do remnant forest patches provide microclimate buffering? A case study from Sri Lanka

Tropical forests have declined in extent considerably owing to large scale deforestation for providing land for multiple uses, and this has reduced their collective capacity to provide many important ecological functions. In the present study, conducted in the tropical island of Sri Lanka, we focus on remnant patches of two common and co-occurring vegetation types in the dry zone, Dry Mixed Evergreen Forest and Scrub Forest, to test (a) whether small remnant forest patches facilitate microclimate buffering and, if so, (b) whether the two forest types differ in terms of their potential to buffer the microclimate, and (c) whether the extent of canopy cover influences the microclimate buffering capacity. Co-occurring Grasslands were used as reference habitats. We used multiple temperature, relative humidity and vapour pressure deficit related metrics, and showed that Dry mixed Evergreen Forest and Scrub Forest had significant microclimate buffering potential, the latter to a lesser extent than the former (Dry mixed Evergreen Forest > Scrub Forest). These results are noteworthy, given that the patches of both forest types were relatively small (mean ± standard deviation: Dry Mixed Evergreen Forest = 0.63 ± 0.13 km2 and Scrub Forest = 0.10 ± 0.07 km2), intermixed and scattered across the same landscape. The study also showed that, after controlling for effects of patch size, the extent of canopy cover had a significant impact on most of the microclimate metrics. The impact of patch size on microclimate metrics was less pronounced. These findings highlight the need for conserving remnant forest patches, especially of the Dry Mixed Evergreen Forest, as refuges of biodiversity, particularly in the context of tropical forests in developing countries facing severe threats of deforestation.

2021–2022年广东南岭站日尺度气象数据集

The mountainous forest and biodiversity ecological functional area of the Nanling Mountain forest ecosystem is one of the 25 key ecological functional areas in China, covering a variety of forest vegetation types, including tropical and subtropical moist broadleaf forests, coniferous broad-leaved evergreen mixed forest, and mountain top evergreen broad-leaved dwarf forest. The tropical and subtropical moist broadleaf forests are the most typical vegetation type in the Nanling Mountains. Monitoring the meteorological elements in the community can help understand the response mechanism of the tropical and subtropical moist broadleaf forests in the Nanling Mountains to climate change. Based on the Nanling Forest Ecosystem National Field Scientific Observation Research station ("Nanling Station" for short) in the Nanling Mountains, Guangdong, we carried out positioning research in Nanling National Nature Reserve. In this paper, we disclosed the raw data of 10 min average wind speed, precipitation, air temperature, air pressure, solar radiation (i.e. total radiation, reflected radiation, ultraviolet radiation, net radiation, photosynthetically active radiation) as well as relative humidity continuously collected in the subtropical evergreen broad-leaved forest area of the Nanling Station from 2021-2022 on a daily scale after data processing, quality control and evaluation. The dataset accessible to the public can serve as a valuable resource for further insights into the Nanling Mountain Forest Ecosystem, and provide foundation for efforts related to the restoration and protection of forest ecosystems.

Three Censuses of a Mapped Plot in Coastal California Mixed-Evergreen and Redwood Forest

Large, mapped forest research plots are important sources of data to understand spatial and temporal changes in forest communities in the context of global change. Here, we describe the data from the first three censuses of the 16-ha UC Santa Cruz Forest Ecology Research Plot, located in the Mediterranean-climate forest on the central coast of California, USA. The forest includes both mixed-evergreen forest and redwood-dominated forest and is recovering from significant logging disturbances in the early 20th century. Each woody stem with a diameter ≥ 1 cm at 1.3 m was mapped, tagged, identified, and measured, with censuses performed at ~5-year intervals. The first census included just 6 ha (previously described), and the area was then expanded to 16 ha in the second census. We describe the temporal dynamics of the forest in the original 6 ha, as well as the structure and temporal dynamics of the full 16 ha. The community includes 34 woody species, including 4 gymnosperm and 9 angiosperm tree species, 18 species of shrubs, and 3 species of lianas. The community includes eight non-native species, representing less than 0.5% of the stems. More than half the species show greater rates of mortality than recruitments, reflective of a dynamic forest community. Over a decade, the number of living woody stems has declined, but the basal area has increased, reflecting a self-thinning process.

A new species of the genus Dibamus Dumril & Bibron, 1839 (Squamata: Dibamidae) from the driest and hottest place of Vietnam.

A new species of the genus Dibamus Dumril & Bibron, 1839 is described based on seven specimens collected from Nui Chua National Park, Ninh Thuan Province, southern Vietnam, the hottest and driest place of the country. Dibamus tropcentr sp. nov. is superficially similar to Dibamus smithi Greer, 1985, but can be distinguished from the latter by: the presence of a rudimentary labial suture; by larger number of subcaudal scales; by comparatively longer tail; by generally larger number of midbody scale rows; by having the interparietal scale not enlarged, subequal to the nuchal scale; by having frontal and frontonasal scales subequal in size as compared to almost twice larger frontal scale in D. smithi; by having three scales posterior to interparietal; by having the medial scale posterior to mental not enlarged; by having three to four scales on the posteromedial edge of infralabials; and by having supralabial scale larger than ocular scale. We suggest the new species should be considered as Vulnerable (VU) following the IUCNs Red List categories. The new species occurs in dry maritime mixed low evergreen forests at elevations of 200280 m a.s.l. and was recorded in association with termite species Globitermes sulphureus (Haviland). Our study brings the total number of species of the genus Dibamus to 25; this is the seventh species of the genus recorded from Vietnam.

Monsoon influence on plant diversity in northern Indochina: Evidence from the late Miocene Yen Bai flora, northern Vietnam

Indochina, as a global biodiversity hotspot, offers the potential for understanding the evolution of biodiversity. However, the historical narrative of plant diversity in this region remains enigmatic due to limited fossil records. Here, we report a newly discovered megafossil flora from the late Miocene of the Yen Bai Basin, northern Vietnam. This megafossil flora suggests that the late Miocene vegetation in northern Vietnam comprised mixed tropical evergreen and deciduous broadleaved forest components mainly characterized by Fabaceae, Fagaceae, and Lauraceae bearing strong resemblance to the modern vegetation in northern Vietnam. Paleoclimate reconstruction for this plant fossil assemblage using the Coexistence Approach indicates a mean annual temperature (MAT) of 18.5–23.0 °C and a mean annual precipitation (MAP) of 1183.1–2078.5 mm. Similarly, employing the Climate-Leaf Analysis Multivariate Program yields an MAT of 21.3 ± 2.3 °C and a growing season precipitation (GSP) of 1328.6 ± 606.0 mm. The length of the growing season was about eleven months. Overall these results indicate a modern-like warm and humid tropical monsoon climate in northern Vietnam during the late Miocene. Climatic comparison of the Yen Bai with other fossil floras in northern Vietnam and southern China reveals the relative stability of temperature seasonality since the middle Eocene but obvious long-term variation in precipitation seasonality, particularly in respect of precipitation during the three consecutive driest months (X3.DRY). This suggests the Asian monsoon in northern Vietnam underwent important changes from the middle Eocene to the late Miocene, and intensified significantly during the middle and late Miocene. Our results show the modernization of plant diversity in northern Indochina had its origin in the Paleogene and further developed in the late Miocene, and was linked to the evolution of the Asian monsoon mainly in terms of changes in dry season precipitation.

Functional adjustment under lethal drought and physiological memory to water stress of two phylogenetically close and coexisting conifers

Forest die-off can primarily affect the least drought-tolerant species and mortality be modulated by physiological legacies left by drought. To characterize the functional response and physiological memory to water stress of two phylogenetically and functionally close conifers with current contrasting field mortality and regeneration dynamics, we conducted a drought experiment in which seedlings were driven to death. Both species exhibited isohydric behavior with small hydroscapes. Yet, hydraulic performance, osmotic adjustment and gas exchange dynamics under rising water stress consistently showed that Pinus pinea was more resistant to drought than Pinus pinaster. Under water stress, P. pinaster exhibited greater water use efficiency, but higher photochemical damage and more constrained photosynthetic and stomatal conductance dynamics than P. pinea. Xylem conductivity loss under water stress and the wilting point were lower in P. pinea. Osmotic potential at full turgor decreased in P. pinea but it increased in P. pinaster with increasing water stress below a water potential threshold. Consequently, lethal water stress levels were higher for P. pinea than for P. pinaster. Synergistically, cumulative water stress induced physiological legacies curtailing carbon uptake and hydraulic performance in both species. Negative physiological legacies left by memory to water stress in plants, might explain delayed tree mortality years after drought. The functional responses to drought characterized agree with current field demographic dynamics under climate change in mixed evergreen forests where more drought-tolerant taxa like P. pinea are replacing formerly dominated P. pinaster stands.

Asynchronous destruction of marsh and forest in Neolithic age: An example from Luotuodun site, Lower Yangtze

The natural marshland and forest landscapes in the Lower Yangtze region have undergone a long history of human-induced destruction; however, little is known about the beginning and process of this destruction. In this study, we investigate the anthropogenic impact on the marsh and forest using cores collected from the vicinity of the Neolithic Luotuodun site, employing palaeoenvironmental and palaeovegetation methods. Our results indicate that the marsh was disturbed by the Neolithic community at 7500 cal yr BP and was completely destroyed at 6500 cal yr BP. Deforestation began at 6500 cal yr BP, and the original mixed broadleaf evergreen and deciduous forest was completely cleared at 4800 cal yr BP. Our findings demonstrate that the Neolithic community in the Luotuodun site prioritized the transformation of marsh in low-lying areas before deforestation. Given that most recent research has focused on pollen-based forest dynamics to study terrestrial landscape changes, the emergence and evolution of anthropogenic landscapes may be greatly underestimated.

Linking rhizosphere soil microbial activity and plant resource acquisition strategy

Abstract Plants live in association with a diversity of soil microorganisms, which are extremely important in affecting plant growth and soil biogeochemical cycling. By adopting plant trait‐based approaches, we explored the linkages between rhizosphere soil microbial activity and plant resource acquisition strategy of above‐ and below‐ground across a range of tree species in a subtropical evergreen mixed forest. The microbial activities were represented by diverse extracellular enzymes relevant to carbon, nitrogen and phosphorus cycling and soil organic carbon (SOC) mineralization. At the species level, leaf and root traits were mainly represented by two leading dimensions, that is, the ‘fast‐slow’ economics spectrum on which leaf and root traits were well aligned and the orthogonal collaboration gradient in the root. Both extracellular enzymes and SOC mineralization in the rhizosphere varied greatly across plant species. We found that diverse rhizosphere soil microbial activities positively correlated with the classical ‘fast‐slow’ conservation gradient of plant resource acquisition (especially above‐ground), that is, the rhizosphere soil microbes associated with fast‐growing plant species feature higher metabolism than that of slow‐growing plant species. In comparison, rhizosphere soil microbial activities were independent of the plant collaboration gradient in the root, and it might be an alternative exploitative strategy in foraging soil nutrients for plants. Synthesis. Our study strengthens the multivariate nature of plant resource acquisition in adapting to above‐ and below‐ground stresses. The findings on the linkages between rhizosphere soil microbial activity and plant resource acquisition strategy have the potential to improve our understanding and prediction of plant species turnover impacts on soil biogeochemical cycles.

A FLORISTIC STUDY OF SWANTON PACIFIC RANCH, SANTA CRUZ COUNTY, CALIFORNIA

The Swanton Pacific Ranch (SPR) is located north of the town of Davenport, in Santa Cruz County, California, and is owned by California Polytechnic State University, San Luis Obispo. SPR is approximately 1295 ha and contains areas of salt marsh, coastal prairie, coastal bluff scrub, northern coastal scrub, riparian forest, redwood forest, mixed evergreen forest, and chaparral. The property extends over an elevational gradient from 0 m to 420 m. In this study, we conducted a floristic inventory at SPR and documented 636 taxa. Between 2017 and 2019 we vouchered 547 taxa with 974 specimens. We were unable to locate 63 taxa that had been previously reported, 27 represented from historic collections and 36 represented by personal observations, but lacking vouchers. We relocated, but did not collect, 26 taxa known from previous collections. Overall, we documented 93 families at SPR, with Asteraceae, Poaceae, and Fabaceae having the most species, respectively. California rare taxa, listed by the California Native Plant Society, made up 2.5% of the flora (n = 18). Locally rare taxa made up 10% of the flora (n = 65). Non-native taxa made up 26% of the flora (n = 169). We vouchered one new taxon for Santa Cruz County, Senecio aphanactis Greene, which has a California Rare Plant Rank of 2B.2; documented a new occurrence of Hesperocyparis abramsiana (C.B.Wolf) Bartel var. abramsiana, a Federally Threatened conifer; and collected a form of Sanicula crassicaulis Poepp. Ex DC that we have published as a distinct variety. Overall, this relatively small coastal ranch contained approximately 10% of the flora of California. The 2020 CZU Lightning Complex Fire burned ca. 90% of SPR within a year of this study being completed. This opens the possibility for this study to be used as a baseline for future studies examining post-fire shifts in plant diversity at a landscape scale.

A dataset of woody plant biomass models for subtropical mixed evergreen and deciduous broad-leaved forests

Tree biomass equations are the most commonly used method to estimate tree and forest biomass on various spatial and temporal scales because of their minor damage, ease of use, and high relative accuracy. The systematic compilation of models for the biomass of mixed evergreen and deciduous broad-leaved forest (a unique and essential class of typical vegetation types in the subtropical zone of China) has not been reported so far. In this paper, we compiled a species list through an inventory of 28.9 hm2 of mixed evergreen deciduous broad-leaved forests in southwestern Hubei Province with fixed detection sample plots, produced a species list, and used it to retrieve, collect and establish a model dataset of woody plant biomass in subtropical mixed evergreen and deciduous broad-leaved forests. The species list contains a total of 665 biomass models in 167 groups as well as the information corresponding to each mode, such as the plant species name, Latin name, plant life type, plant components calculated by the model, model independent variables, measurement units and ranges of independent variables, model correlation coefficient or coefficient of determination, model sample size, climate zone, and soil type. is also recorded. By establishing this dataset, this paper not only provides essential information for in-depth research on the productivity and carbon sink of this specific vegetation but also serve as a scientific basis for the management of this type of forest, the conservation of biodiversity, and the evaluation of forest ecological benefits.

Schoenorchis mishmensis sp. nov. (Orchidaceae) from Mishmi Hills, Lower Dibang Valley District, Arunachal Pradesh, India

A new species of Schoenorchis, belonging to the family Orchidaceae is described from tropical mixed evergreen forests of Mishmi Hills, (Arunachal Pradesh, India). It is allied to Schoenorchis micrantha and S. brevirachis but differs in the size and shape of plant, the size of the leaf blade, inflorescence and flower. A detailed description with taxonomic notes, colour photos and information on the habitat, conservation status are provided.

How far westward? Revisiting the distribution of Arctonyx badgers in the westernmost global range

Abstract Bangladesh delimits the westernmost range of Arctonyx badgers, but their presence in the country is not completely understood. The whole of Bangladesh is reportedly home to the northern hog badger (A. albogularis); however, there is no valid record to date. The greater hog badger (Arctonyx collaris), its larger congener and a globally vulnerable mustelid, has three valid records. This work, between 2001 and 2021, traced 28 records (all of A. collaris: 20 from literature review and social media, 8 from camera-trapping) in Bangladesh including four rare cases of erythrism and seven conflict incidents. All but five were from mixed evergreen forests of southeast Bangladesh, the known A. collaris range. One record was from wet deciduous forests of northern Bangladesh (bordering Meghalaya, India), a region not previously marked as an A. collaris range. In 2021, from 4436 trap-nights of sampling, 17 notionally-independent events (all night-time) were obtained. This produced the first evidence of A. collaris in northeast Bangladesh, a region that borders the Tripura Hills, India (where it was first recorded in 2020) and belongs to the Indo-Burma biodiversity hotspot. The work proves the existence of relict populations whereas the absence of A. albogularis signifies a re-assessment of its westernmost distribution.

Impact of Aboveground Vegetation on Abundance, Diversity, and Biomass of Earthworms in Selected Land Use Systems as a Model of Synchrony between Aboveground and Belowground Habitats in Mid-Himalaya, India

The population status and biomass of earthworms were studied in three different land use systems of pasture (Pa), silvopasture (SP), and mixed evergreen forest (MEF) from 2019–2020 in the Solan district of Himachal Pradesh, India. The aim of this study was to assess the population status of earthworms and investigate how different land use systems influence their abundance, diversity, and biomass. Earthworms and soil were sampled using the Tropical Soil Biology and Fertility (TSBF) method in all seasons (winter, spring, summer, monsoon, and autumn). The physicochemical properties of the soil were analyzed to evaluate their effects on the diversity, biomass, and density of animals. The diversity status parameters, such as the Shannon diversity index (H′), Margalef richness index (R), evenness (J′), and dominance index (D), were computed. A total of seven earthworm species, belonging to four families, namely, Amynthas corticis, Aporrectodea rosea, Drawida japonica, Eisenia fetida, Metaphire birmanica, Metaphire houlleti, and Lennogaster pusillus, were identified from all three land use systems. The lowest Shannon diversity index (H′), Margalef index (R), and evenness (J′) index values were registered in MEF (H′ = 0.661, R = 0.762, J′ = 0.369) compared to those in Pa (H′ = 1.25, R = 1.165, J′ = 0.696) and SP (H′ = 0.99, R = 0.883, J′ = 0.552), implying that MEF is the least diversified land system. In contrast, the highest dominance index (D) value was registered in MEF (Pa = 0.39, SP = 0.53, MEF = 0.67), which again showed that MEF is the least diversified land system. The highest values of abundance and biomass were recorded in MEF (754.15 individuals m−2 and 156.02 g m−2), followed by SP (306.13 individuals m−2 and 124.84 g m−2) and Pa (77.87 individuals m−2 and 31.82 g m−2). Both the density and biomass of earthworms increased from Pa to MEF (Pa < SP < MEF). This study is novel because it revealed that the diversity and productivity (biomass and abundance) values of earthworms were negatively correlated (as diversity increased, productivity decreased; as diversity decreased, productivity increased). The total values of abundance and biomass of earthworms in the three land use systems indicated perfect synchrony between aboveground and belowground habitats, whereas the diversity values revealed that MEF was dominated by one or two species and the least diversified. Therefore, for sustainable belowground productivity, aboveground conservation is recommended, and vice versa, regardless of diversity.

Vertical thermal environment of subtropical broad-leaved urban forests and the influence of canopy structure

Urban forests alter the surface energy balance and provide a comfortable thermal environment. However, little quantitative research exists on the relationship between their vertical temperature structure and influence on the urban thermal environment. In this study, we aimed to measure the differences and determine the correlations between the canopy temperature (T1), below-canopy air temperature (T2), below-canopy ground surface temperature (T3), and soil temperature (T4) of three forests: evergreen broad-leaved forest (EBF), deciduous broad-leaved forest (DBF), and mixed evergreen and deciduous broad-leaved forest (MBF) in Zhejiang Province, China. The thermal environment of DBF fluctuated greatly, whereas that of EBF and MBF was relatively stable. T1 was highly and significantly correlated with T2 (r > 0.850, p < 0.01) and T3 (r > 0.790, p < 0.01) in EBF and MBF; thus, T1 is a good predictor of T2 and T3 in EBF and MBF. T4 was susceptible to the external thermal environment and correlated relatively well with T2 (r = 0.879) in DBF. MBF and EBF had substantial cooling effects, with mean values of T2 and T3 2.4 and 2.3 °C, and 10.1 °C and 10.7 °C lower than the air and surface temperatures in the areas without canopy shade, respectively. Ambient temperature and humidity, solar radiation, canopy thickness and density, tree number, and tree species and height significantly influenced the thermal environment and cooling effect of the forests. The results of this study provide an important reference for the future design of thermally comfortable urban landscapes.

Moso bamboo (Phyllostachys edulis) invasion increases forest soil pH in subtropical China

Soil pH has cascading effects on terrestrial ecosystem functions by regulating the biogeochemical cycle, which can be altered by plant invasion. Bamboo invasion occurs throughout the world in both native and introduced habitats, especially in Asia. However, the effect of bamboo invasion on soil pH is still poorly understood. Here, we investigated the invasion-induced change in pH (CIP) with pairwise sampling from 215 bamboo-tree transects in subtropical China, including 203 pure bamboo forest (BF) plots, 188 mixed bamboo-tree forest (MBTF) plots and 199 non-bamboo-invaded tree forest (TF) plots. We found a significant increase in soil pH after bamboo invasion from 4.44 (±0.03) in TFs to 4.52 (±0.03) in MBTFs and 4.67 (±0.03) in BFs. The CIP was related to the invaded forest type, with the largest changes in deciduous broadleaf (0.38 ± 0.09) and mixed evergreen and deciduous broadleaf forests (0.38 ± 0.10), followed by mixed needleleaf and broadleaf forests (0.24 ± 0.05), and the smallest changes in evergreen broadleaf (0.19 ± 0.03) and needleleaf forests (0.20 ± 0.03). Further analysis showed that the CIP increased linearly with invasive bamboo density and was independent of climate factors. Overall, we provide the first evidence of a large-scale observation for bamboo invasion-induced forest soil pH increase. Our findings highlight that plant invasion should not be neglected as a driver of global change via its effects on soil pH.

Effects of different vegetation restoration on soil nutrients, enzyme activities, and microbial communities in degraded karst landscapes in southwest China

The karst area in southwestern China is one of the largest and continuous karst landforms in the world, and its ecosystem is highly sensitive and fragile. Appropriate vegetation restoration modes are of great significance for sustaining and improving the stability of the karst ecosystem, the dominant landform type in southwest China. Bacteria, linking soil and plants, play an important role in regulating the succession and restoration of karst vegetation. However, it remains unclear how soil bacterial communities and soil biochemical properties respond to vegetation restoration practices in karst areas. In this study, a 13-year long-term trial was performed using three planting restoration modes of deciduous broad-leaved, mixed evergreen and deciduous broad-leaved forest, and evergreen broad-leaved forests, with controls of natural enclosure. We aimed to investigate the impact of different vegetation restoration modes on the structure of soil microbial communities and their driving mechanisms using 16S rDNA Illumina sequencing, combined with the determination of 11 soil indicators and statistical models. The results showed that artificial restoration can improve soil nutrient contents, enzyme activities and microbial biomass more effectively than natural closure, which is beneficial to the rapid restoration of vegetation after abandoning of farmland. Among them, the effect of deciduous broad-leaved treatment on artificial restoration mode was better than that of mixed evergreen and deciduous broad-leaved forest and evergreen broad-leaved forest. In sequencing results, artificial restoration increased the relative abundance of Proteobacteria, but decreased that of Acidobacteria. In addition, pH, soil microbial biomass carbon, and urease activity significantly increased bacterial diversity. Different vegetation restoration measures significantly changed the soil bacterial community structure. The bacterial community of deciduous broad-leaved forest was the most beneficial to the benign development of soil. Mantel test showed that pH and soil microbial biomass carbon and nitrogen were the key driving factors of the soil bacterial community. FAPROTAX analysis showed a significant positive correlation between sucrase activity and phototrophy functional bacteria. The results demonstrated that compared with natural enclosure, artificial vegetation restoration promoted rapid community succession, and construction of deciduous broad-leaved forest was the most effective way to manage karst areas, improve soil nutrients, alter its key microbial populations, promote ecosystem services, and eventually benefit the restoration of vegetation in karst areas.

The early middle Eocene Wagon Bed carpoflora of central Wyoming, U.S.A.

The early middle Eocene Wagon Bed fruit and seed flora of central Wyoming encompasses nine morphotypes that are assignable to extant genera (Alangium, Aphanathe, Canarium, Carya, Celtis, Iodes, Mastixia, Nyssa, Pleiogynium), four that are assignable to extinct genera in extant families (Chandlera, Menispermaceae; Coryloides, Betulaceae; Pentoperculum, Anacardiaceae; Saxifragispermum, Salicaceae) and one morphotype potentially assignable to an extant family (Pandanaceae). At least 11 morphotypes remain unidentified due to incomplete characters, although some exhibit features suggestive, but not definitive, of extant families (e.g., Euphorbiaceae, Lauraceae, Nymphaeaceae, Rosaceae). Individual taxa exhibit paleobiogeographic links with the Eocene floras of the west coast of North America, as well as with those of the Eocene of Europe. Together with previously described pollen and woods, these fruits and seeds indicate a mixed evergreen and deciduous forest, existing under moist circumstances, possessing primary taxonomic affinities with extant paratropical taxa of the Old World.

Bulbophyllum karbianglongensis (Orchidaceae, Epidendroideae), a new species from Assam, India

A new epiphytic Bulbophyllum belonging to section Cirrhopetaloides is described from tropical mixed evergreen forests of Karbi Anglong (Assam, India) with coloured photographs and line drawings. It is allied to the Bulbophyllum bicolor, B. venulosum and B. blaoense, but differs in the size and shape of pseudobulbs, the shape of the leaf blade, and flower size. A detailed description with corresponding color photos and information on the habitat is provided.

Short-term avian responses to experimental variable-density thinning: Initial stand attributes outweigh effects of management in Austral temperate rainforests

Anthropogenic environmental changes have led to secondary forests becoming dominant in many regions. Although ecological or restoration thinnings can help restore old-growth conditions, experimental evidence of their subsequent benefits to biodiversity remains sparse, particularly in Austral Temperate Rainforests in South America. Using mist-net sampling within 1-ha plots in mixed-evergreen and Nothofagus secondary forests, we examined short-term effects (4 years) of experimental Variable Density Thinning (VDT) on bird richness, abundance, and the individual body condition of two abundant breeding species: frugivore Elaenia albiceps and insectivore Aphrastura spinicauda. Based on 518 birds captured, richness and relative abundance were higher in Nothofagus than in mixed-evergreen forests, regardless of VDT treatment, except for E. albiceps which was more abundant in mixed-evergreen forests. Richness and abundance did not vary with VDT treatment, except for E. albiceps which increased in abundance following VDT. However, individual body condition of E. albiceps did not change due to VDT management, although it was better in mixed-evergreen than in Nothofagus forests, and increased over the course of the study. In contrast, body condition of A. spinicauda was not associated to VDT treatment, forest type, or season. Our results suggest that the short-term effects of VDT in secondary Austral Temperate Rainforests upon avian richness, abundance, and individual body condition were minimal, and that initial stand attributes (i.e. forest type) more strongly influenced these variables. This is likely due to the region’s high diversity of tree species, which drives substantial differences in tree species composition among forest types and affects the food resources available to birds. In this case, most trees in mixed-evergreen forests produce fleshy fruits that are important in the diet of E. albiceps and other bird species. Therefore, in geographical regions with a high alpha and beta tree diversity, restoration thinnings in secondary forests should explicitly target tree composition, which appears to be at least as important as vegetation structure in determining short-term avian responses.

Influence of Scale Effect of Canopy Projection on Understory Microclimate in Three Subtropical Urban Broad-Leaved Forests

The canopy is the direct receiver and receptor of external environmental variations, and affects the microclimate and energy exchange between the understory and external environment. After autumn leaf fall, the canopy structure of different forests shows remarkable variation, causes changes in the microclimate and is essential for understory vegetation growth. Moreover, the microclimate is influenced by the scale effect of the canopy. However, the difference in influence between different forests remains unclear on a small scale. In this study, we aimed to analyze the influence of the scale effect of canopy projection on understory microclimate in three subtropical broad-leaved forests. Three urban forests: evergreen broad-leaved forest (EBF), deciduous broad-leaved forest (DBF), and mixed evergreen and deciduous broad-leaved forest (MBF) were selected for this study. Sensors for environmental monitoring were used to capture the microclimate data (temperature (T), relative humidity (RH), and light intensity (LI)) for each forest. Terrestrial laser scanning was employed to obtain the canopy projection intensity (CPI) at each sensor location. The results indicate that the influence range of canopy projection on the microclimate was different from stand to stand (5.5, 5, and 3 m). Moreover, there was a strong negative correlation between T and RH, and the time for T and LI to reach a significant correlation in different urban forests was different, as well as the time for RH and LI during the day. Finally, the correlation between CPI and the microclimate showed that canopy projection had the greatest effect on T and RH in MBF, followed by DBF and EBF. In conclusion, our findings confirm that canopy projection can significantly affect understory microclimate. This study provides a reference for the conservation of environmentally sensitive organisms for urban forest management.