Pak Nok Toby Tsang

• Post-doc
• The University of Hong Kong

1. Studies along broad spatial and habitat gradients evidence that organisms’ traits can influence community assembly through their impact on dispersal and environmental filtering. However, the role of traits in structuring local faunal communities within habitats remains poorly understood. In particular, the often-assumed role of traits in affecti...

Urban areas are foci for the introduction of non‐native plant species, and they often act as launching sites for invasions into the wider environment. Although interest in biological invasions in urban areas is growing rapidly, and the extent and complexity of problems associated with invasions in these systems have increased, data on the compositi...

Land use change threatens global biodiversity and compromises ecosystem functions, including pollination and food production. Reduced taxonomic α‐diversity is often reported under land use change, yet the impacts could be different at larger spatial scales (i.e., γ‐diversity), either due to reduced β‐diversity amplifying diversity loss or increased...

Land use change threatens global biodiversity and compromises ecosystem functions, including pollination and food production. Reduced taxonomic α-diversity is often reported under land use change, yet the impacts could be different at larger spatial scales (i.e., γ-diversity), either due to reduced β-diversity amplifying diversity loss or increased...

Land use change threatens global biodiversity and compromises ecosystem functions, including pollination and food production. Reduced taxonomic α-diversity is often reported under land use change, yet the impacts could be different at larger spatial scales (i.e., γ-diversity), either due to reduced β-diversity amplifying diversity loss or increased...

1. Urban areas are foci for the introduction of non-native plant species, and they often act as launching sites for invasions into the wider environment. Although interest in biological invasions in urban areas is growing rapidly, and the extent and complexity of problems associated with invasions in these systems have increased, data on the compos...

Urban ecology and tropical biology have both developed rapidly in recent decades and matured into important interdisciplinary fields, with significant implications for biodiversity and human communities globally. However, urban ecosystems within the tropics remain understudied and poorly characterized despite these systems representing major hotspo...

The globalization of trade and increased human mobility have facilitated the introduction and spread of nonnative species, posing significant threats to biodiversity and human well-being. As centers of global trade and human populations, cities are foci for the introduction, establishment, and spread of nonnative species. We present a global synthe...

Insect biogeography is poorly documented globally, particularly in the tropics. Recent intensive research in tropical Asia, combined with increasingly available records from citizen science, provides an opportunity to map the distributions of tropical Asian butterflies. We compiled a dataset of 724,247 occurrences of 3,591 tropical Asian butterfly...

Widespread species experience a variety of climates across their distribution, which can structure their thermal tolerance, and ultimately, responses to climate change. For ectotherms, activity is highly dependent on temperature, its variability and availability of favourable microclimates. Thermal exposure and tolerance may be structured by the av...

Identifying the drivers that promote unique species compositions (i.e. ecological uniqueness) is crucial to understanding the mechanisms underpinning diversity patterns and for effective conservation planning. Environmental conditions are often sampled differentially in datasets, which can lead to rarer environments having unique species compositio...

Aim The vulnerability of montane species to environmental change has been increasingly recognized in recent years. However, most of these species are regionally endemic with restricted distributions, limiting dispersal necessary for avoiding extinction. The outcome of threats posed for montane lizards is further complicated in species exhibiting ma...

Early naturalists such as Humboldt observed that changes in topography and anthropogenic disturbances influenced vegetation structure and the composition of animal communities. This holistic view of community assembly continues to shape conservation and restoration strategies in an era of landscape degradation and biodiversity loss. Today, remote s...

Aim Ecological theory has predicted that species richness should stabilize communities, with mechanisms including species synchrony and population variability determining the net impacts. While these theories have been supported empirically, results can be sensitive to taxonomic bias as studies are often focussed on plants. Trophic differences betw...

Perceptions of, and attitudes toward, wildlife are influenced by exposure to, and direct experiences with, nature. Butterflies are a conspicuous and ubiquitous component of urban nature across megacities that are highly urbanized with little opportunity for human–nature interactions. We evaluated public familiarity with, perceptions of and attitude...

While essential in understanding impacts of climate change for organisms, diel variation remains an understudied component of temporal variation in thermal tolerance limits [i.e. the critical thermal minimum (CTmin) and maximum (CTmax)]. For example, a higher Ctmax might be expected for an individual if the measurement is taken during the day (when...

Critical Thermal maximum (CTmax) is often used to characterize the upper thermal limits of organisms and represents a key trait for evaluating the fitness of ectotherms. The lack of standardization in CTmax assays has, however, introduced methodological problems in its measurement, which can lead to questionable estimates of species’ upper thermal...

Diversity metrics, essential for habitat evaluation in conservation, are often based on occurrences records with little consideration of behavioral ecology. As species use diverse habitats to perform different behaviors, reliance on occurrence records alone will fail to reveal environmental conditions shaping the behavioral importance of habitats w...

In ectothermic predator‐prey relationships, evasion of predation by prey depends on physiological and behavioural responses relating to the thermal biology of both predator and prey. On Japan's Izu Islands, we investigated a prey lizard's physiological and thermal responses to the presence of a snake predator over geologic time in addition to recen...

Interspecific competition, a dominant process structuring ecological communities, is influenced by species' phenotypic differences. Limiting similarity theory holds that species with similar traits should compete intensely (‘trait‐similarity'). In contrast, competing theories including modern coexistence theory emphasize that species with traits co...

Upper thermal limit (UTL) is a key trait in evaluating ectotherm fitness. Critical Thermal maximum CT max , often used to characterize the UTL of an organism in laboratory setting, needs to be accurate to characterize this significant and field-relevant threshold. The lack of standardization in CT max assays has, however, introduce methodological p...

Observations of coral reef losses to climate change far exceed our understanding of historical degradation before anthropogenic warming. This is a critical gap to fill as conservation efforts simultaneously work to reverse climate change while restoring coral reef diversity and function. Here, we focused on southern China’s Greater Bay Area, where...

The effects of climatic warming on tropical streams have received little attention, and field studies of such changes are generally lacking. Drifting insects from a Hong Kong forest stream were sampled for 36 months between 2013 and 2016, and compared with samples collected by identical methods in 1983‐84. Mean air temperatures rose by ~0.5°C (0.17...

Diets of species are crucial in determining how they influence food webs and community structures, and how their populations are regulated by different bottom‐up processes. Omnivores are able to adjust their diet flexibly according to environmental conditions, such that their impacts on food webs and communities, and the macronutrients constraining...

Climate change is predicted to impact tropical rain forests, with droughts becoming more frequent and more severe in some regions. We currently have a poor understanding of how increased drought will change the functioning of tropical rain forest. In particular, tropical rain forest invertebrates, which are numerous and biologically important, may...

Interspecific competition, a dominant process structuring ecological communities, acts on species' phenotypic differences. Species with similar traits should compete intensely (trait-similarity), while those with traits that confer competitive ability should outcompete others (trait-hierarchy). Either or both of these mechanisms may drive competiti...

Urban areas suffer high pressure of introductions of alien species compared to other habitats due to intensive human activities. As trading globally continues to rise, more species will likely be introduced into urban areas. To determine whether this increase in introduction pressure will lead to increased alien species richness in urban areas, or...

ContextEnvironmental processes and dispersal are primary determinants of metacommunity dynamics. The relative importance of these effects may vary between species of different abundance classes, given variation in life history traits. Under high disturbance conditions, rare species may be more easily eliminated from their optimal habitats and their...

Species are threatened globally by multiple and often synergistic environmental changes including habitat loss, fragmentation and climate change. However, how these changes act in concert is poorly understood, especially in the tropics where the vast majority of biodiversity resides. Here, using a unique dataset covering 10 years of butterfly surve...