Kenneth B. H. Er’s research while affiliated with Singapore Botanic Gardens and other places

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Publications (35)


Ten survey sites located in the study: Five at the Main Road (labeled M1 to M5) and five at the Service Road (labeled S1 to S5). Each survey site consisted of a paired deployment of camera traps to monitor culvert crossings and closed‐circuit televisions to monitor road crossings (marked with red rectangles). * ‐ Two rope bridges were also installed at sites M3 and M5 and they were monitored using motion‐sensitive cameras. Photo credits: Eunice Kong.
Number of crossing events of all 14 species detected. In total, 1133 crossing events were recorded: 610 crossing events for culverts, 397 crossing events for roads, and 126 crossing events for rope bridges. Symbols on the names of each mammal species indicate the result of the χ² post hoc test for differences in number of crossings between road and culverts (*p < 0.05; **p < 0.01; ***p < 0.001).
Nonmetric multidimensional scaling (NMDS) plot for species composition using each wildlife crossing infrastructure at each survey site. Ellipses around each crossing type represent the 95% CI. The species composition using rope bridges were distinct and separate from those using culverts and roads for crossing. For culverts and roads, there were some overlap in the species composition, but the mammal community using culverts were more varied than those using roads for crossing.
Activity patterns of crossing events that occurred in culverts and roads for the three most commonly detected species and for all other species combined: (A) wild boars, (B) common treeshrew, (C) stray dogs, (D) remaining 10 species combined. The coefficient of overlap (Δ) is represented by the shaded region under the curves. For this study, daylight hours are designated as 07:00–19:00. The activity plot for common treeshrews using the road has been excluded due to the low frequency of detections (n = 3) to determine a reliable activity plot. The activity plot for stray dogs only included road crossings as they were not recorded to use culverts.
Bayesian estimate of the means and difference of means between monthly crossing rates for culverts and roads. (A, B) Estimates for mean number of monthly crossings for culverts and road respectively for wild boars only. (C) Difference in means for culvert and road crossing for wild boars. In this plot, the 95% highest density interval (HDI) region does not overlap with region of practical equivalence (ROPE). (D, E) Estimates for mean number of monthly crossings for culverts and road respectively for all other mammal species combined. (F) Difference in means for culvert and road crossing for all other mammal species. In this plot, the 95% HDI region partially overlaps with ROPE.

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A suite of wildlife crossing structures facilitates mammal movement across tropical forest fragments in a city
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December 2024

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133 Reads

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Ruisheng Choo

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Kenneth B. H. Er

Wildlife crossing structures and road calming measures are frequently implemented to improve habitat connectivity and mitigate the risks of wildlife–vehicle collisions on roads. Although Southeast Asia is a known biodiversity hotspot, majority of studies assessing effectiveness of such structures were conducted outside the region. Existing studies also tended to be non‐comparative and focused on crossing structures in silo. We addressed this gap by simultaneously surveying and comparing the usage frequency of mammals across three crossing types—culverts, roads and rope bridges—along a road surrounded by forests in Singapore. This allowed us to evaluate the preferences of mammals, assess usage patterns and investigate factors influencing the use of different crossing types. Using camera traps and closed‐circuit televisions, we documented 1133 independent crossing events across a 9‐month study period from March to November 2021. Fourteen mammal species were detected across all crossing types, with wild boar (Sus scrofa) being the most prevalent species (68.2%). Locally critically endangered species such as the Malayan porcupine (Hystrix brachyura), Sunda pangolin (Manis javanica), and Raffles' banded langur (Presbytis femoralis femoralis) were also recorded to use culverts, roads, and rope bridges for crossings, respectively. Although many species used multiple crossing types, most species had a preferred crossing method. Between culverts and roads, factors that influenced crossing preferences included group size for wild boars and time of day and presence of fences for other mammals. Even though such culverts were intended for drainage, they were still widely used by mammals. Overall, all three crossing methods were crucial in facilitating the movement of animals between habitats. Thus, a variety of infrastructure and measures to accommodate the diversity of wildlife moving across forest patches in a fragmented landscape is recommended.

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Fig. 1. Changes in the number of Singapore native orchid taxa listed from 1900 to present (2023). The green line (square markers) indicates the total number of taxa listed while the orange line (triangle markers) indicates the number of extinct taxa. *Holttum did not usually treat Singapore as separate from southern Peninsular Malaysia.
Fig. 2. The proportions of new orchid records and rediscoveries in Singapore from 2009 to 2023 which resulted from recent field collections and from taxonomic work on pre-existing specimens.
Rediscovering and conserving orchids in a tropical city-state

December 2024

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23 Reads

Gardens’ Bulletin Singapore

The conservation status of orchids in the city-state of Singapore mirrors the worldwide decline of this group of plants, one of the largest families of flowering plants. Despite this, the number of extant native orchids has been revised from 45 to 76 in the last 15 years largely due to taxonomic revisions and (re-)discoveries. Building on the history of orchid taxonomic research in the Singapore Botanic Gardens and the revival of plant systematics in Singapore, these recent successes reflect efforts in establishing resident taxonomists and field ecologists, embracing integrative taxonomy, undertaking comprehensive botanical surveys, and developing an opportunistic instinct to discover orchids in the field. Coupled with ongoing species recovery efforts, this provides a sense of optimism for conservation and suggests that small habitat fragments characteristic of cities could continue to be refugia for native orchids. This also further illustrates the important role that botanic gardens play in the conservation of endangered plant species.


(a) Two roost sites chosen in Singapore for data collection. Roost site 1 was the primary target for visual and acoustic data collection. Roost site 2 had no clear view for visual data analysis, but was used for acoustic data analysis. Illustrative projections of the microphone beamwidth and virtual markers for Cameras 1 and 2 depicted in orange dotted lines, and blue and red frames respectively. Sample video frames showing birds detected in yellow boxes on Camera 1 (b) and Camera 2 (c) while flying in and out of the roost site.
(a) Deep neural network (DNN) architecture to convert acoustic data to myna count. The input data size is 4096 samples (250 ms) of acoustic data at a sampling rate of 16,384 Hz. Each convolution layer down samples with a stride of 2, while increasing the number of filters from 1→8→16→32. The data from the 32 filters is mean‐pooled, flattened and passed through 2 dense hidden layers with 32 and 16 neurons each, and then fed into an output dense layer with a single neuron. The output of that neuron is finally scaled to give the myna count estimate. (b) Complete processing chain from acoustic recording to timeseries of myna count estimates. The recording is bandpass filtered in the 1–5 kHz band and then split into 1‐min blocks, and further split into 4096 sample (250 ms) chunks. Each 4096 sample chunk passes through the DNN (detailed in part a) to yield a point myna count estimate. The count estimates are statistically pooled over each 1‐min block to yield a timeseries of median and a 50% confidence interval.
(a) Myna count estimates (median) from acoustic roost size estimation model (“Acoustic” in blue) as a function of time, compared against the estimates from visual analysis (“Camera” in red). The light blue ribbon is the 50% confidence interval from the model. Orange outline shows the count estimation using the training data while the other plots are representative of validation data. (b) Temporal evolution of estimated bird count based on the acoustic roost size estimation model, as compared with the estimate from visual analysis, for test datasets collected on 17 September 2021, (c) 20 August 2020 and (d) 31 August 2020 at roost site 2—a rough visual estimate of the roost size is provided since part of the roost tree was occluded with foliage from another tree.
A novel method for estimating avian roost sizes using passive acoustic recordings using deep neural network

October 2024

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44 Reads

Communal bird roosts serve as information centres and a means of thermoregulation for many species. While some communally roosting species are major pests and cause dis‐amenities, others are of conservation concern. Estimating the population of roosting birds can provide a useful proxy of population size and possibly a more reliable estimate than other sampling techniques. However, estimating these populations is challenging as some roosts are large and often occluded in foliage. Previous acoustic methods such as paired sampling, microphone arrays and use of call rate have been used to estimate bird abundances; however, these are less suited for estimating large roost populations where hundreds of individuals are calling in unison. To address this challenge, we explored using machine learning techniques to estimate a roost population of the Javan myna, Acridotheres javanicus, an invasive species in Singapore. While one may expect to use sound intensity to estimate roost sizes, it is affected by various factors such as distance to the recorder, local propagation conditions (e.g. buildings and trees), weather conditions, and noise from other sources. Here, we used a deep neural network to extract higher order statistics from the sound recordings and use those to help estimate roost sizes. Additionally, we validated our method using automated visual analysis with a dual‐camera setup and manual bird counts. Our estimated bird counts over time using our acoustic model matched the automated visual estimates and manual bird counts at a selected Javan myna roost, thus validating our approach. Our acoustic model estimated close to 400 individual mynas roosting in a single tree. Analyses of additional recordings of Javan myna roosts conducted on two separate occasions and at a different roost location using our acoustic model showed that our roost estimates over time also matched our automated visual estimates well. Practical implication: Our novel approach of estimating communal roost sizes can be achieved robustly using a simple portable acoustic recording system. Our method has multiple applications such as testing the efficacy of avian roost population control measures (e.g. roost tree pruning) and monitoring the populations of threatened bird species that roost communally.


Urban bird commensals maintain coexistence under extreme food shortages

October 2024

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103 Reads

In developed cities, bird communities are typically comprised of a few dominant invasive species that can cause considerable social and economic costs. While various studies advocate restricting anthropogenic food as a suitable management approach, a significant knowledge gap persists regarding how these species interact and respond to such an intervention. Here, we evaluate whether limiting a shared food resource may affect their abundances similarly and assess whether such limitations influence their niche dynamics. In Singapore, open food centres for people, colloquially known as hawker centres, serve as key food sources for three highly adapted urban birds: feral pigeons, Javan mynas and house crows. We counted these three species across 63 hawker centres and analysed their niche dynamics across different phases—before, during COVID‐19 social restrictions when dining‐in was prohibited, and during an enforcement phase mandating the return of crockery. We modelled their counts, diet niche widths and niche overlaps, considering predictors which include the sampling phases, food availability, structural characteristics of hawker centres and spatial attributes such as distance to public housing. During social restrictions, feral pigeon and Javan myna counts showed a significant decline, while the count proportions of the three species compared to each other remained relatively stable. Hawker centres closer to bridges and public housing, and those that structurally more open, attracted more birds. The niche widths of feral pigeons and Javan mynas significantly narrowed during social restrictions due to reduced food availability. However, their niche overlaps remained consistent across sampling phases, indicating resource partitioning strategies to cope with extreme food shortages—feral pigeons adapted by foraging more on grass verges outside, while Javan mynas frequented tray return stations. This resilience in maintaining species proportions and the absence of significant niche overlap suggested the existence of an ecological balance despite substantial reductions in available food. Synthesis and applications. Our study underscores the importance of controlling human‐provided food to collectively manage dominant urban bird commensals. Beyond the two social restriction phases, curbing the availability of anthropogenic food through enforcement also kept nuisance birds away, validating a cost‐effective approach in reducing their counts.


Why do understorey Licuala palm fruits turn from red to white and then black when ripe?

September 2024

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105 Reads

Licuala ferruginea Becc., a tropical forest understorey palm, is observed to have fruits that appear red in colour when unripe, turning pink, then white, purple and finally black in colour as they ripen. We monitored 13 fruiting palms in rainforest fragments and recorded the consumption of fruits by animals via camera traps. We also documented the fruiting phenology of two palms in the nursery. In the rainforest fragments, a Cream‐vented Bulbul (Pycnonotus simplex) was observed plucking a mature purple fruit from a L. ferruginea palm, before flying away with the fruit in its beak. This was the only bird that was observed feeding on the mature fruit. A range of mammals, dominated by edge species such as the Long‐tailed Macaque and Wild Boar, were observed to consume L. ferruginea fruits indiscriminately across all five colour stages, thereby limiting the dispersal of the fruits. Forest bulbul gape sizes also matched the fruit size, suggesting that forest bulbuls are the likely dispersers of the palm in the original forest where edge species are not in high densities. We further posit that the initial phase of red fruits, with high contrasting red reflectance against a green foliage background, might be a form of early advertisement to birds. The fruit then turns pink and white, which have high green reflectance and is less contrasting, thereby reducing the conspicuity of the fruit. This allows the fruit to ripen with high fructose and glucose content, and turn purple and black, which are known visual cues for birds. This study provides indicative support for the dispersal syndrome hypothesis and highlights the potential effects of forest fragmentation on plant–frugivore interactions.


Leaf flush intervals for species monitored in both Holttum's study and the present monitoring; y‐axis is on the logarithmic scale. EG, evergreen; for other categories, see Table 1. Horizontal lines and shaded regions represent the mean and 95% confidence interval of the estimated intervals in the model. See Figure S2 for all species including those that were monitored in one of the studies only.
(a) Weights of models from sliding window analysis using mean daily rainfall within a varying window period as the predictor variable of a leaf flushing event. These models used species as random slopes; for the corresponding results from models using species as random intercepts, see Figure S3. White cross indicates the best‐ranked model. (b) Estimated species coefficients of the relationship between leaf flushing and mean daily rainfall for this best model. N refers to the number of individuals monitored for that species; dotted line indicates the overall slope coefficient of the model.
(a) Predicted mean daily rainfall from the best generalised additive model of annual rainfall pattern differences between Holttum's time (red) and the present day (blue); lines show predicted mean daily rainfall, and shaded regions represent 95% confidence bands. Trends in mean daily rainfall in (b) February and (c) May from 1929 to 2022. (Note that trendlines at the start and end of the period should be interpreted with caution.)
Changes in tropical leafing behaviour with climate change over nine decades: A case study from the Singapore Botanic Gardens

September 2024

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83 Reads

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1 Citation

Societal Impact Statement Long‐term phenology data is crucial to elucidate the effects of climate change on plants, but such efforts are lacking in the tropics. Historical records at the Singapore Botanic Gardens and ongoing phenological monitoring have allowed us to study leafing behaviour and its association with changing rainfall patterns over nine decades in equatorial Singapore. We found that the leafing behaviour of trees in our tropical site changed between 1927 and 2022. This study was made possible by assiduous past and present record‐keeping, and demonstrates the potential of botanical gardens as sentinels of environmental change, which is especially important in the tropics. Summary Understanding tropical phenology and the potential impacts of a changing climate requires long‐term monitoring but such efforts are rare in the tropics. We took advantage of the availability of historical phenological and weather records at the Singapore Botanic Gardens and ongoing phenological monitoring to ask whether leafing behaviour has changed over an exceptionally long period of about nine decades, and whether these changes are associated with changing rainfall patterns in supposedly aseasonal Singapore. Records of leaf flush intervals from 1927 to 1939 in the Singapore Botanic Gardens were compared against leaf flush intervals calculated from present‐day phenological monitoring conducted since 2016. Daily rainfall was modelled as a predictor of present‐day leaf flushing events using moving‐window analyses. Leaf flush intervals have shortened considerably for most of the species that were monitored in the two periods. Mean daily rainfall over a window of 1 to 4 months before was negatively associated with probability of leaf flushing for five species and positively associated with four out of a total of 23 species analysed. Long‐term rainfall records from 1929 to 2022 show that February has become drier and May has become wetter since the 1960s. The results consistently support that more distinctive dry and wet periods today compared to nine decades ago have resulted in more frequent leaf flushing, which may have implications for plant‐herbivore interactions, nutrient cycling and consequently plant health and ecosystem resilience. We also demonstrate the potential and importance of supporting long‐term research in botanical gardens in the tropics.


Crow ladder trap. Crows enter through the ladder entrance area and are not able to fly out with their wings extended.
Crow trap deployment sites in Singapore from March 2022 to June 2023. Each point indicates 1 trap (darker shading reflects overlap of trap location symbols that are close to each other).
Predictor plots of the zero‐truncated gamma model of crows caught per day against (A) Number of feeding incidents within a 500‐m radius, (B) Crow density and (C) Proportion of human‐managed vegetation within a 250‐m radius.
Trapping efficacy of invasive crows is affected by environmental factors and deployment history

July 2024

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116 Reads

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1 Citation

House crows (Corvus splendens) are considered an invasive species and are prevalent in parts of Europe, Africa, and Southeast Asia. Existing crow management measures include food limitation, habitat modification, and direct population control. The latter method provides a more immediate solution, particularly in nesting locations where crow attacks occur more frequently. Crow ladder traps are widely adopted to capture crows, but a thorough examination of the environmental conditions that optimize trapping efficacy is lacking. We assessed factors affecting crow trap efficacy in Singapore to better advise future deployment strategies of crow traps. We obtained data from 170 crow trapping operations including the identities of the contractors conducting the trapping operations, operation start date, crow density, intensity of bird feeding, various land use cover proportions, and an index to quantify the spatial‐temporal proximity to previous trapping operations. We used a spatial gamma generalized linear mixed model (GLMM) to determine the factors affecting the daily number of crows captured and a spatial binomial GLM to determine the factors affecting the probability that crows will be captured. The number of bird‐feeding incidents had a negative effect on crow trap efficacy suggesting that crows are probably less inclined to enter traps if proximate anthropogenic food abundance is high. Trapping efficacy increased if traps were placed in high crow‐density areas, likely because more crows could detect the traps. The probability of capture also declined if the traps were placed closer to prior trapping locations or with a shorter time interval from previous trapping operations. Capture rates of crows can be increased by placing traps in high crow density areas, limiting bird‐feeding incidences, and lengthening the spatial and temporal proximities to previous trapping operations. The deployment of ladder traps is a viable means to control the population of house crows and consideration of environmental conditions and trapping history can improve capture rates.



Conservation genetics and status of Orania sylvicola palms in Singapore -native relicts or historical re-introductions?

June 2024

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112 Reads

Gardens’ Bulletin Singapore

Orania sylvicola (Griff.) H.E.Moore is a large, single-stemmed palm species widely distributed across Malesia. It is the only species of Orania present in Peninsular Malaysia and Singapore. In Singapore, the species is rare and critically endangered, although a full understanding of its distribution is hampered by sparse historical collections. However, conflicting records on the known localities in the literature, along with a recent discovery of a substantial population of Orania sylvicola within the Tyersall Learning Forest in Singapore Botanic Gardens, have led to questions on the origin of the extant populations of O. sylvicola. There are known instances of past introductions of non-native plant species in Singapore, which raised suspicions that some of the individuals were historical reintroductions from overseas. Genetic analyses, a comprehensive survey of existing literature and herbarium collections, and a topographical study of existing Orania sylvicola populations were carried out to determine the origin of these individuals in Singapore. Our results suggested that all Orania sylvicola individuals in Singapore are of native origin, with two populations present. The distribution of the two populations overlaps in the Singapore Botanic Gardens, which may indicate that some of the plants have been transferred to the Botanic Gardens from another location in Singapore. Preliminary results also revealed that sampled populations within Peninsular Malaysia and between Peninsular Malaysia and Singapore are highly differentiated from each other with very little gene flow either by pollen or seed dispersal. Our study highlights how the integration of genetic information, historical collections and topographical analyses can contribute to assessing the origin and conservation potential of endangered plant species in Singapore and provide insights into suitable conservation actions for Orania sylvicola.


Citations (24)


... Similar results were found in the Singapore Botanic Gardens, where Ho et al. (2024) conducted a long-term assessment of changes in leafing behavior of tropical trees in response to climate change. They found that tropical trees can adjust their leafing behavior over extended periods, showcasing their adaptive capacity. ...

Reference:

Trees, society, and the path toward resilient ecosystems
Changes in tropical leafing behaviour with climate change over nine decades: A case study from the Singapore Botanic Gardens

... Likewise, he encouraged close collaboration between the Gardens and Pasir Panjang Nursery on ex-situ native plant conservation and species recovery, and Wildlife Management division and NBC on research projects. The result of these efforts could be seen in the completion of four milestone research projects that have since been published -1) A comprehensive biodiversity survey of Bukit Timah Nature Reserve by Chan and Davison (2019); 2) Flora of Singapore: Checklist and bibliography by Lindsay et al. (2022); 3) An account of the re-discovery of 173 presumed nationally extinct plant taxa and discovery of 155 new native plant records in Singapore over 14 years, including 22 new to science and five endemics by Neo et al. (2024); and 4) A study of the birds in the Gardens' Rainforest that showed how avian functional diversity was retained after more than 120 years of turnover by Low et al. (2024). When K.B.H. Er sent the Low et al.'s paper to Dr Leong as he was undergoing the last stages of chemotherapy before his passing, he remarked in his usual serious but happy tone, "This is important science." ...

Avian functional diversity retained in a tropical rainforest fragment after more than 120 years of turnover

Biodiversity and Conservation

... Until the collection from the Nee Soon Pipeline in 2011, the species was not recorded from Singapore. Despite Singapore being comparatively very well collected within Malesia (see Middleton et al., 2019), activities toward the Flora of Singapore programme, including additional fieldwork, collecting and critical re-appraisal and identification of herbarium material, has resulted in 150 additional species added to the flora of the island in a 14-year period from 2009-2023 (Neo et al., 2024). Climbing taxa, especially lianas reaching the canopy, were highlighted by Neo et al. (2024) as one of the groups previously overlooked by previous botanists and requiring specialist attention. ...

A botanical oasis rather than a biological desert: Rediscoveries, new species and new records in a tropical city

... In March 2020, SARS-CoV-2 sequence analysis revealed human-to-animal transmission 60 in five tigers and three lions at the Bronx Zoo, making non-domestic felids among the first documented non-human animals infected with SARS-CoV-2 through viral spillover 17,18 . Large felids have since constituted the majority of animal infections reported in zoological settings, with cases most commonly associated with respiratory signs and virus detection in oronasal samples and/or feces 16, [19][20][21][22][23][24][25][26][27][28][29][30][31][32] . Furthermore, putative lion-to-human spillback has also been 65 reported 33 . ...

Anthropogenic Transmission of SARS-CoV-2 from Humans to Lions, Singapore, 2021

Emerging Infectious Diseases

... Two-hundred and forty-four records of D. auratus and/or coordinates of collection sites were retrieved from 28 publications from the Web of Science Core Collection; 13 'supplementary publications'; and from the USNTC. These 244 records were from 1935 to 2023 and 25 of these records (10 %) had detected pathogens in D. auratus (Tan et al., 1967;Boshell et al., 1968;Sumrandee et al., 2016;Nooroong et al., 2018;Asyikha et al., 2020;Misra et al., 2021;Chaloemthanetphong et al., 2023;Koh et al., 2023). Sixteen of the 244 records were removed because they were records identified prior to Wassef and Hoogstraal (1984) (n = 8); or were records from Taiwan (Guglielmone et al., 2023) (n = 1) or from China which we considered to be doubtful (n = 7) (Supplementary Materials). ...

Detection of African Swine Fever Virus from Wild Boar, Singapore, 2023

Emerging Infectious Diseases

... For example, the critically endangered (CR) brown Asian giant tortoise has been consumed by the Semoq Beri indigenous people in Pahang [19]. However, this species has also been utilized in Indonesia for wildlife trading and traditional medicine, where it is believed to aid in musculoskeletal health [20,21]. Additionally, primate species, including the dusky leaf monkey and white-handed gibbon, have been reported as a source of food among the Semoq Beri and Temuan people in Peninsular Malaysia [22,23]. ...

A systematic survey of the online trade in elephant ivory in Singapore before and after a domestic trade ban

Oryx

... Previous studies have shown that the regular and proper maintenance of facilities can also increase satisfaction with parks [10,12]. Appropriate friendly park design can make citizens more willing to engage with the community and society [13,14]. In the current ...

Use and non-use of parks are dictated by nature orientation, perceived accessibility and social norm which manifest in a continuum
  • Citing Article
  • July 2023

Landscape and Urban Planning

... An ongoing national tick surveillance program based around a standardised methodology should be implemented. With sampling efforts focused on opportunistic tick screening on wildlife and companion animals as well as regular monitoring (e.g., quarterly) of fixed forest plots across Singapore such as those highlighted by Er et al. (2023) which are already used for forest ecology research. This would support estimations of the seasonal abundance of local ticks and the early detection of invasive tick species. ...

Establishing a network of long-term forest monitoring plots in Singapore
  • Citing Article
  • June 2023

Gardens’ Bulletin Singapore

... Unsurprisingly, nesting closer to major food sources is clearly more energy efficient and yields higher nesting success (Hunt Jr., 1972;Kristan III & Boarman, 2007;Meyrier et al., 2017). The numerous expansion gaps in bridges and air-conditioning fan coil units and ledges in public housing estates are often used for nesting by feral pigeons (Haag-Wackernagel & Geigenfeind, 2008;Lim et al., 2023;Tang et al., 2018). Javan mynas also use man-made structures for nest sites, but are frequently observed using tree cavities for nesting (Arazmi et al., 2022;Yap & Sodhi, 2004). ...

Proximity to anthropogenic food sources determine roosting and nesting prevalence of feral pigeons (Columba livia) in a tropical city

... GCIs can be conceptualized as the outcome of multi-level interactions between public authorities and actors from diverse sectors, including health, social services, education, and green/blue area management [12,20,21]. These actors are crucial as their actions and management interventions can facilitate the provision of accessible, safe, and appropriate green or blue spaces, including urban parks, forests, lakes, coasts, and protected areas, where individuals can engage in positive and effective nature-based health experiences. ...

The contributions of urban horticulture to cities' liveability and resilience: Insights from Singapore