Stephan W. Gale’s research while affiliated with Kadoorie Farm and Botanic Garden and other places

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Publications (91)


Fig. 4 Number of times each environmental variable, restoration treatment and their interactions selected in the generalised linear models examining seedling survival. Details of the models are in Table S2
Fig. 6 Relative importance of the selected factors for RGR . a RGR of seedling height 2014-2015 (2.4% of variation explained). b RGR of seedling height 2015-2017 (1.4% of variation explained). c RGR of basal diameter 2014-2015 (1.9% of variation explained). d RGR of basal diameter 2015-2017 (2.8% of variation explained)
Temporal shifts in the importance of environmental factors and management interventions among species in the early stages of forest restoration
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April 2025

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57 Reads

Journal of Forestry Research

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Stephan W. Gale

Both abiotic conditions and management influence the success of forest restoration. Despite growing interest and practical effort in restoring degraded forest landscapes, understanding of how disparate factors, such as terrain, soil conditions, climate and silvicultural treatments, directly or collectively control species performance and shape community recovery remains limited. In this study, we assessed how topography and management intervention affect seedling survival and growth in the early stages of restoration. To do so, we established seven experimental plots, each measuring 20 m × 20 m (400 m ² ) subdivided into 48 subplots, in coarse, anthropogenic grassland on a mid-elevation mountain slope in Hong Kong, and planted a total of 3975 native tree seedlings belonging to 12 tree species within them. To characterise topography, we modelled the elevation, slope, convexity and aspect of each subplot. Two types of tree guard (enclosed blue plastic sleeve and open yellow mesh), two types of fertiliser (organic and inorganic) and cardboard weeding mats were used to assess the impact of management interventions on the establishment of the seedlings. Survivorship, height and basal diameter were measured at 1, 2 and 4 years after planting. We used generalised linear models to examine the effect of these factors and their interactions on seedling survival, and we applied linear models and hierarchical partitioning to explore their relative importance in determining the relative growth rate (RGR) of each species. The most parsimonious models were selected using the Akaike Information Criterion. Survivorship was 98.1%, 95.2% and 86.4% across all plots in the first, second and fourth year, respectively. On average, topographic and management variables explained 1.48–3.34% of total variation in RGR, respectively, for all species. The models revealed that type of tree guard, aspect and elevation were the most important factors explaining RGR and survival. Results of hierarchical partitioning by species and growth period showed that the key determinants of performance vary by species and shift over the course of early seedling establishment, emphasising the importance of both spatial and temporal scales in the restoration of degraded tropical forests. Our findings support the use of enclosed tree guards and fertiliser to improve survivorship and growth across a range of broadleaved Asiatic species. All potential limiting factors pertaining to both site factors and management, as well as their interactions, should be considered in restoration planning to maximise restoration success.

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Morphological conservatism and sectional division in Nervilia. (A–H’) Section Linervia. (I–J’) Section Vinerlia. (K–N’) Section Nervilia. (A, A’) Flower and leaf of N. adolphi var. adolphi in Tanzania. (B, B’) Flower and leaf of N. alisanensis in China (Hainan). (C, C’) Flower and leaf of N. juliana in India. (D, D’) Flower and leaf of N. khaoyaica in Thailand. (E, E’) Flower of N. mackinnonii in Thailand and leaf of N. cf. mackinnonii (sample MY73 in Table 1 ) in Myanmar. (F, F’) Flower and leaf of N. taiwaniana in Taiwan. (G, G’) Flower and leaf of N. simplex in Malawi. (H, H’) Flowers and leaf of N. cumberlegei in Taiwan. (I, I’) Flowers and leaf of N. plicata in China (Hong Kong). (J, J’) Flowers and leaf of N. plicata in Thailand. (K, K’) Flowers and leaf of N. concolor in Thailand. (L, L’) Flowers and leaf of N. kotschyi var. kotschyi in Kenya. (M, M’) Flowers and leaf of N. campestris (=N. holochila) in Indonesia. (N, N’) Flower and leaf of N. maculata in Thailand.
Phylogram obtained from Bayesian inference (BI) analysis of the combined ITS and ptDNA data sets. Numbers at the nodes indicate bootstrap percentages and Bayesian posterior probabilities, respectively. “-” indicates that the node collapsed in MP analysis. Sectional affiliation is indicated at right, as is the extent of the species-rich Nervilia adolphi-punctata alliance (shown in purple).
Spatio-temporal reconstruction of Nervilia according to the best-fit model (DEC+J) inferred by BioGeoBEARS and the maximum clade credibility tree obtained by BEAST analysis. The blue bar at each node indicates the 95% credibility intervals with mean node ages (Mya) shown above. Coloured rectangles correspond to the four biogeographic regions defined for the purposes of this study: blue (1) indicates Africa & Madagascar, green (2) seasonal tropical Asia, orange (3) moist tropical Asia and red (4) Oceania. Grey boxes indicate taxa that span two or more biogeographic regions. The worldwide occurrence of Nervilia is shown inset (grey shaded area), with the coloured polygons corresponding to the four biogeographic regions. Numbers shown in each polygon indicate the total number of Nervilia species known in that region according to POWO (2024) on the left of the forward-slash, followed by the number of species sampled in this study and the total number of samples in brackets.
Statistics relating to the phylogenetic data sets used in this study.
BioGeoBEARS estimation of ancestral areas for Nervilia.
Molecular phylogenetic analyses reveal multiple long-distance dispersal events and extensive cryptic speciation in Nervilia (Orchidaceae), an isolated basal Epidendroid genus

February 2025

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217 Reads

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1 Citation

Introduction The terrestrial orchid genus Nervilia is diagnosed by its hysteranthous pattern of emergence but is nested among leafless myco-heterotrophic lineages in the lower Epidendroideae. Comprising ca. 80 species distributed across Africa, Asia and Oceania, the genus remains poorly known and plagued by vague and overlapping species circumscriptions, especially within each of a series of taxonomically intractable species complexes. Prior small-scale, exploratory molecular phylogenetic analyses have revealed the existence of cryptic species, but little is otherwise understood of origin, the scale and timing of its biogeographic spread, or the palaeoclimatic factors that have shaped its ecology and given rise to contemporary patterns of occurrence. Methods Here, we sample widely throughout the generic range, including 45 named taxa and multiple accessions referable to several widespread ‘macrospecies’, as well as material of equivocal identity and probable undescribed status, for the first time enabling an evaluation of taxonomic boundaries at both species and sectional level. Using nuclear (ITS) and plastid (matK, trnL-F) sequence data, we conduct phylogenetic (maximum parsimony and Bayesian inference) and ancestral area analysis to infer relationships and resolve probable origin and colonisation routes. Results The genus is strongly supported as monophyletic, as are each of its three sections. However, the number of flowers in the inflorescence and other floral characters are poor indicators of sectional affinity. Dated ancestral area analysis supports an origin in Africa in the Early Oligocene, with spread eastwards to Asia occurring in the Late Miocene, plausibly via the Gomphotherium land bridge at a time when it supported woodland and savanna ecosystems. Discussion Taxonomic radiation in Asia within the last 8 million years ties in with dramatic Himalayan-Tibetan Plateau uplift and associated intensification of the Asia monsoon. Multiple long-range migrations appear to have occurred thereafter, as the genus colonised Malesia and Oceania from the Pliocene onwards. The bulk of contemporary species diversity is relatively recent, potentially explaining the ubiquity of cryptic speciation, which leaves numerous species overlooked and unnamed. Widespread disjunct species pairs hint at high mobility across continents, extinction and a history of climate-induced vicariance. Persistent taxonomic challenges are highlighted.


Maximum Likelihood (ML) tree of the new species and related species. Bootstrap values of the Maximum Likelihood are shown along the branches. Outgroups: Melicytus obovatus. Viola tenuis are marked in grey.
Viola tenuis Benth. a habitat and habit (photograph in Hong Kong, J. Zhang) b flower, front view c flower, side view d leaf and stipules e bracteoles f ovary and stigma g stamens h seeds.
a holotype of Viola tenuis Benth. (K000370141) b, c specimen of V. tenuis in KFBG (JG0615, HKY0012).
Distribution of Viola tenuis Benth.
On the identity and typification of Viola tenuis Bentham (Violaceae)

February 2025

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54 Reads

Viola tenuis Benth. was first described by George Bentham in 1842, without any type specimen designated, but with a collection record by Richard Brinsley Hinds in 1841. Currently, Viola tenuis is considered a synonym of another species according to Plants of the World Online (POWO). However, based on a combination of morphological and molecular evidence, we propose reinstating Viola tenuis as a distinct species. Our analysis places it within Viola sect. Plagiostigma subsect. Diffusae, where it shows morphological similarities to five other species endemic to Guangdong Province, China. We designated the type of V. tenuis here and assigned additional KFBG specimens to the species.



Fig. 2. Relative contribution of IUCN categories to the small fin survey. Bar-plot showing the contribution of threatened [vulnerable (vU), endangered (en), or critically endangered (CR)] species to the shark fin trade based on small fin data by number of species (top) and by contribution of fins (bottom). nt, near threatened; lC, least concern.
Fig. 5. Geographic distribution of species present in the small fin trade. Overlapping species distributions present in the small fin trade to FAO-MFAs. numbers denote area codes assigned by FAO.
Species richness estimations for shark fin trimmings using abundance data. Ci, confidence interval; Se, standard error; Mle, maximum likelihood estimation; ACe, abundance-based coverage estimator.
Small sharks, big problems: DNA analysis of small fins reveals trade regulation gaps and burgeoning trade in juvenile sharks

October 2024

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179 Reads

Science Advances

Many shark species have been overexploited for international markets, including fins for shark fin soup in Southeast Asia. Previous studies highlighted the value of large, threatened shark species, regulated under CITES Appendix II. However, sampling biases may have overlooked small shark species. Here, we address this by identifying species from ~4000 small shark fins in Hong Kong. These fins included species not recorded in previous surveys, raising the market’s species diversity to 106. Nearly 75% of the small fins came from small shark species and 58.1% of small species were threatened with extinction. We identified an important CITES listing gap: Trade in 19 small, threatened species, especially from the family Triakidae, is unregulated. In addition, a quarter of small fins come from large sharks, indicating that substantial exploitation of juveniles is occurring and may be affecting fisheries sustainability. Enhanced surveillance of small shark fin trade is essential to ensure effective conservation under emerging trade regulations.



1092. Begonia hongkongensis F.W.Xing: Begoniaceae

May 2024

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41 Reads

Curtis&apos s Botanical Magazine

Begonia hongkongensis F.W.Xing is described and illustrated. Begonia section Platycentrum series Aequilateralibus , to which it belongs, is likely to be an artificial group defined by its symmetrical leaf base, a feature that is atypical for the genus as a whole, but which may have evolved as an adaptation to flash floods since it is associated with rheophytic and streamside species of tropical areas with very high annual rainfall. Variation within the species and relationships with morphologically similar species are discussed.


Tai Po Kau ForestGEO Forest Dynamics Plot: Species Composition and Community Structure

April 2024

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310 Reads

The Tai Po Kau Forest Dynamics Plot was established in 2015 following standard ForestGEO protocols. It is located within the core area of Tai Po Kau Nature Reserve in the New Territories of Hong Kong S.A.R., China. The plot measures 500 m by 400 m (i.e. 20 hectares, ha) and, in the first census completed in 2015, it contained 81,019 individuals of 172 woody species, amounting to 117,203 stems, each equal to or greater than 1 cm diameter at breast height. These species belong to 111 genera in 53 families. This handbook presents a map indicating the occurrence of each of these species within the plot, as well as notes on their ecology, phenology and key identification characteristics, including photos. The Tai Po Kau Forest Dynamics Plot is the first in the ForestGEO worldwide network to be established in secondary forest. As such, it offers a unique opportunity for integrated research into the impacts of disturbance on tropical biodiversity. This book is therefore intended as a foundation for deepening understanding of the ecology, conservation and restoration of degraded tropical landscapes.



Citations (61)


... Historically, Hong Kong was covered by broad-leaved evergreen forests, but extensive deforestation occurred before and during the Second World War in the 1940s [54]. Much of the current forest cover consists of secondary forests that have regenerated naturally or through plantation efforts [54,55]. In contrast, small pockets of remnant forest known as Fung Shui Woods (FSWs) have survived for over 100 years [56], with some even exceeding 300 years in age [57] (Figure 1b). ...

Reference:

Mapping Individual Tree- and Plot-Level Biomass Using Handheld Mobile Laser Scanning in Complex Subtropical Secondary and Old-Growth Forests
Integrating both restoration and regeneration potentials into real-world forest restoration planning: A case study of Hong Kong
  • Citing Article
  • August 2024

Journal of Environmental Management

... Agarwood, also known as oudh or gaharu, is a highly valued resinous wood product that is widely used to make incenses, perfumes, medicines and artisanal ornaments (Thompson et al., 2022). Escalating demand for agarwood has triggered over-exploitation of agarwood-producing species (Kwok et al., 2024). To ensure the sustainability of the trade, all species in the three agarwood-producing genera, Aquilaria, Gyrinops and Gonystylus of Thymelaeaceae are listed in CITES Appendix II (Gratzfeld and Tan, 2008). ...

Life history traits associated with high fecundity help offset the worst genetic impacts of targeted poaching in Aquilaria sinensis

Global Ecology and Conservation

... Diverse, seasonal tropical and evergreen rainforests were the primeval vegetation of Hong Kong (Corlett 1999;Zhu et al. 2023), with an estimated 150-180 woody species per ha, as found in nearby protected areas of South China (Fang et al. 2004;Xu et al. 2015) and northern Vietnam (Zhu and Roos 2004). However, virtually all original forest cover had been cleared by the 1600s as a result of centuries of human disturbance, and so today the only remaining old-growth forest fragments are small, isolated feng shui woodlands restricted to the lowlands and remote, mid-elevation slopes (Marafa 2003;Chen et al. 2018;Lee et al. 2023). Significant secondary regeneration has occurred since the Second World War, mostly in moist ravines and on slopes protected from manmade fire at middle to upper elevations. ...

Can Disparate Shared Social Values Benefit the Conservation of Biodiversity in Hong Kong’s Sacred Groves?

Human Ecology

... A total of 656 plant species were recorded in 115 of Hong Kong's > 300 FSW (ibid.), accounting for 30% of the territory's entire native flora (Zhu et al., 2018(Zhu et al., , 2023; nowadays, many are completely confined to FSW (Chu, 1998;Kadoorie Farm and Botanic Garden, 2023). Many villages associated with FSW whose residents traditionally maintained them through active use have been abandoned over the last 50 years (Chu, 1998). ...

Additions to the Flora of Hong Kong, China

... • Inhibition of Natural Succession: The combination of dense monoculture planting, severe ground disturbance, understory suppression by shade and allelopathy, and the lack of diverse seed sources actively inhibits natural ecological succession and the potential future colonization by other native plant and associated faunal species (Zhu et al., 2023;Pérez-Gómez et al., 2024). This locks the site into a simplified, low-diversity, and low-resilience state, failing to restore the full complexity and functionality of a native forest ecosystem, including critical processes like pollination and nutrient cycling which depend on diverse plant and soil life (Gamfeldt et al., 2013;Zhou, X. et al. 2017). ...

Monoculture plantations impede forest recovery: Evidence from the regeneration of lowland subtropical forest in Hong Kong

Frontiers in Forests and Global Change

... As for G. elata, Cyrtosia septentrionalis (Rchb.f.) Garay (syn. Galeola septentrionalis) is a fully MH orchid that is thought to switch mycobiont as it transitions through seed germination, protocorm development and subsequent life history phases (Umata et al., 2022). Over the course of their life, plants of this species develop a giant body comprising an extensive root system of 20 or more extended adventitious roots, some of which may reach up to 5 m in length, as well as numerous shorter lateral roots (Hamada, 1939;Umata et al., 2022); some individuals produce more than 30 flower-Variable, life stage-dependent mycorrhizal specificity and its developmental consequences in the fully myco-heterotrophic orchid Cyrtosia septentrionalis ing shoots, each attaining up to 1.7 m in height (Chen & Cribb, 2009;Hamada, 1939;Umata et al., 2022). ...

Spatial separation of mycobionts in the giant, differentiated root system of Cyrtosia septentrionalis, a fully myco-heterotrophic orchid

... It is noteworthy that A. nipponica is occasionally treated as a synonym of A. wallichii. However, A. nipponica can be distinguished by its smaller size, with leaves up to 5 cm in length, while A. wallichii typically reaches 10 to 50 cm in height (Kumar & Gale 2022). Despite the significant difference in leaf size, the flower size remains similar in both species (Kumar & Gale 2022). ...

Taxonomic notes on Apostasia nipponica and Crepidium cordilabium (Orchidaceae), two species newly recorded from Hong Kong
  • Citing Article
  • July 2022

Feddes Repertorium

... Crassulacean acid metabolism (CAM) is a photosynthetic pathway that has evolved convergently in multiple plant lineages, especially in species inhabiting water-limited environments, such as hot semi-arid areas and tropical forests Xue et al., 2023). Recent studies have indicated that the majority of epiphyte plants use the CAM pathway (Holtum et al., 2007), including bromeliads (Hermida-Carrera et al., 2020), pteridophytes (Silvera et al., 2010), and orchid species (Givnish et al., 2015;Zou et al., 2018;Gamisch et al., 2021;Hu et al., 2022;Zhang et al., 2022b). CAM photosynthesis, which has evolved at least four times within Orchidaceae, is thought to be a key innovation that has driven orchid diversity. ...

Diversification Slowdown in the Cirrhopetalum Alliance (Bulbophyllum, Orchidaceae): Insights From the Evolutionary Dynamics of Crassulacean Acid Metabolism

... & Souvann., was found near the border of Bolikhamxay Province near the Mekong River. This location lies within one of Laos' most important protected areas, the Phou Khao Khouay National Biodiversity Conservation Area, where several endemic plant species occur (Tagane et al., 2018;Mattapha et al., 2021;Souvannakhoummane et al., 2021). ...

Cymbilabia sourioudongii (Orchidaceae), a new species from Lao PDR.

Rheedea

... The species of this genus are characterized by multinodal, pseudobulbous stems bearing roots at the base and two or more plicate leaves; a racemose terminal inflorescence that rises above the leaves, bearing multiple flowers that are either loosely or densely arranged and are often doubleresupinate (appearing non-resupinate) (Margońska et al. 2012); a usually flat, usually ecallose labellum with a cavity at the base of the column, the cavity divided into two chambers; a deeply lobed labellum base with side lobes extending beyond the column, a notched or dentate apical margin; and a short column with a pair of prominent staminodes near the apex. The anther is dorsally positioned on the column, with pollinia lacking a viscidium (Kumar et al. 2022). However, both the subtribe and the genus are plagued by taxonomic challenges, with no universal consensus reached to date (Kumar et al. 2022). ...

Integrative analyses of Crepidium (Orchidaceae, Epidendroideae, Malaxideae) shed more light on its relationships with Dienia , Liparis and Malaxis and justify reinstatement of narrow endemic C. allanii
  • Citing Article
  • March 2022

Botanical Journal of the Linnean Society