Pei-Jen Lee Shaner

• PhD
• Professor at National Taiwan Normal University

Understanding factors influencing the spatio-temporal patterns of apex predators is prerequisite for their conservation. We studied space use and diel activity of tigers (Panthera tigris) in response to prey availability and anthropogenic activities with trail cameras in Nepal during December 2022–March 2023. We used hierarchical occupancy models t...

Nests are considered extended phenotypes of animals with potentially serious fitness consequences for the survival of offspring. Therefore, nest characteristics may contain valuable information about the underlying ecological and evolutionary mechanisms shaping animal reproduction. However, we currently lack efficient tools to archive nests and mea...

1. Individual niche specialization is widespread in natural populations and has key implications for higher levels of biological organization. This phenomenon, however, has been primarily quantified in resource niche axes, overlooking individual variation in environmental associations (i.e. abiotic conditions organisms experience). 2. Here, we expl...

Little is known about the behavioral and cognitive traits that best predict invasion success. Evidence is mounting that cognitive performance correlates with survival and fecundity, two pivotal factors for the successful establishment of invasive populations. We assessed the quantity discrimination ability of the globally invasive red-eared slider...

Prey behavioral responses to predation risk cues may vary between species; moreover, the strength of these behaviors may differ depending on risk cue. In northwestern Taiwan, we used the giving up density (GUD) framework supported with camera trap observations to test how two wild murid rodents that differ by up to fivefold in body size (striped fi...

Species with similar ecological characters often compete with each other; however, a species may also facilitate the survival or reproduction of another ecologically similar species, although such interaction is rarely documented in birds. Here, we reported a facilitative species interaction between Asian house martins (Delichon dasypus) and russet...

Niche variation at population level mediates niche packing (i.e. patterns of species' spread within the niche space) and species coexistence at community level. Competition and ecological opportunity (resource diversity) are two of the main mechanisms underlying niche variation. Dense niche packing could occur through increased niche partitioning o...

Rodents threaten agricultural industries and food security on a global scale. Rodent management practices routinely involve the use of chemical products, mainly anticoagulant rodenticides (ARs). An understanding of farmer rodent control behaviors is crucial in order to implement management changes to more environmentally friendly practices. In this...

Pests cause devastating losses on agricultural industries worldwide. Common pest management practices include using chemical products. The efficacy of these toxins remains inconclusive, however, and their application can have adverse effects on non-target wildlife from both direct and indirect exposure. In parts of Taiwan, threatened species may be...

Ecogeographic rules that describe quantitative relationships between morphologies and climate might help us predict how morphometrics of animals was shaped by local temperature or humidity. Although the ecogeographic rules had been widely tested in animals of Europe and North America, they had not been fully validated for species in regions that ar...

Background Quantity discrimination, the ability to discriminate a magnitude of difference or discrete numerical information, plays a key role in animal behavior. While quantitative ability has been well documented in fishes, birds, mammals, and even in previously unstudied invertebrates and amphibians, it is still poorly understood in reptiles and...

The niche variation hypothesis (NVH) predicts that populations with wider niches exhibit greater morphological variation through increased interindividual differences in both niche and morphology. In this study, we examined niche–trait relationships in three passerine species (Cyanoderma ruficeps, Sinosuthora webbiana, and Zosterops simplex). A tot...

Background: Understanding how wild species respond to novel situations with associated risk can provide valuable insights for inter-specific behavioral variation and associations with pace-of-life (POL). Rodents, a globally distributed and diverse taxonomic group, have been the subjects of countless studies emulating risky situations. Controlled l...

Background: Rodents, a globally distributed and diverse taxonomic group, have been the subjects of countless studies emulating risky situations. In controlled laboratory experiments the majority of focus has been on captive-bred rodents, whereas far less attention has been paid to their wild counterparts. Understanding how wild species respond to n...

Background: Understanding how wild species respond to novel situations with associated risk can provide valuable insights for inter-specific behavioral variation and associations with pace-of-life (POL). Rodents, a globally distributed and diverse taxonomic group, have been the subjects of countless studies emulating risky situations. Controlled la...

Quantifying ecosystem resilience is critical for predicting how shifts in disturbance regime affect ecosystem structure and function as a result of recent climate change. Studies of disturbance-ecosystem interactions often focus on one or a few disturbance events but the interactions may vary considerably among disturbance events. We used a 25-year...

Based on 20,000 records representing c. 11,000 individuals from an 8-year capture-mark-recapture (CMR) study, we tested and confirmed a new case of invariant clutch size (ICS) in a sexually dichromatic lacertid lizard, Takydromus viridipunctatus. In the grassland habitat of the early succession stage, females showed strictly low and invariant clutc...

The red panda Ailurus fulgens is categorized as Endangered on the IUCN Red List and is threatened by anthropogenic pressures such as livestock grazing. We surveyed people living in or near protected areas and people living away from protected areas in Nepal, to understand human attitudes towards red panda conservation. Given Nepal's participatory a...

With rapid urbanization worldwide, anthropogenic impacts such as human settlements and invasive carnivores (dogs Canis familiaris, cats Felis catus) are altering spatial distributions and temporal activity patterns of native species. In this study, we focused on spatiotemporal responses of native mammals to anthropogenic impacts in a protected area...

Phylogenetic analysis has shown that males' propensity to engage in aggressive encounters is associated with females having greater longevity. Here, we confirm the causal link between aggression and reduced longevity by looking at an egg-eating snake (Oligodon formosanus) in which females defend territories in the presence of sea turtle eggs. We mo...

Litter and vegetation under forest canopy (i.e., understory vegetation) are known to reduce soil erosion and contribute substantially to evapotranspiration. However, previous studies rarely examined understory water interception. We conducted a comprehensive study of rainfall partitioning using a water balance equation that included both overstory...

Many properties of forest ecosystems, such as species composition and forest structure, naturally vary with forest age. However, in regions prone to cyclone disturbances, both forest age and cyclone severities can play a role shaping these properties. To evaluate potential effects of an altered cyclone regime on forest ecosystems, it is necessary t...

Information on species distribution range is a prerequisite for setting conservation strategies. Conservation efforts in Nepal have been focused on flagship species, such as Bengal Tiger (Panthera tigris), Asian Elephant (Elephas maximus) and Greater One-horned Rhinoceros (Rhinoceros unicornis). By contrast, distribution data and conservation effor...

Chien-Lung Chen and Pei-Jen L. Shaner (2018) Resource events such as typhoon-triggered greenfall have consequences for multiple ecological mechanisms, ranging from population dynamics and trophic interactions to ecosystem processes. Arthropods are sensitive to environmental disturbances, and many taxa have been used as indicator species. In a field...

Food and parasitism can have complex effects on small mammal reproduction. In this study, we tested the effects of sex, food, and parasitism on reproductive performance of the Taiwan field mouse (Apodemus semotus). In a field experiment, we increased food availability for a portion of the mice in the population by providing sorghum seeds to a set o...

The vertebrate extinction rate over the past century is approximately 22–100 times greater than background extinction rates [1], and large mammals are particularly at risk [2, 3]. Quaternary megafaunal extinctions have been attributed to climate change [4], overexploitation [5], or a combination of the two [6]. Rhinoceroses (Family: Rhinocerotidae)...

This corrects the article DOI: 10.1038/srep23087.

Host spacing may benefit the parasites (e.g., enhance parasite transmission) or the hosts (e.g., reduce host infection), with profound consequences in epidemiology and host–parasite dynamics. In this study, we tested parasitism effects of intestinal nematodes on spacing behaviors and spatial recruitment of the Taiwan field mouse (Apodemus semotus)....

The tradeoff between reproduction and survival, which is driven by physiological processes and ecological agents, is a central theme in life-history theory. For male vertebrates, survival cost of reproduction may be mediated through testosterone level and parasitism: a high level of testosterone reinforces secondary sexual traits and mating perform...

Foraging host individuals can defend against fecal–orally transmitted parasites by avoiding feces-contaminated patches, which has been widely documented among ungulates. However, it remains unclear whether smaller-sized hosts (e.g., mice), with their high metabolism and constant needs for energy acquisition, can afford the same behavioral strategy....

Appendix S1. Locality, abbreviation, latitude, longitude, elevation, mean temperature and sample sizes of Microhyla fissipes and M. heymonsi for each sample locality used in this study. Appendix S2. Illustrations of the temporal and spectral properties of the advertisement call of a Microhyla fissipes individual. Appendix S3. Acoustic characteris...

Acoustic signals for mating are important traits that could drive population differentiation and speciation. Ecology may play a role in acoustic divergence through direct selection (e.g., local adaptation to abiotic environment), constraint of correlated traits (e.g., acoustic traits linked to another trait under selection), and/or interspecific co...

Microsatellites have a wide range of applications from behavioral biology, evolution, to agriculture-based breeding programs. The recent progress in the next-generation sequencing technologies and the rapidly increasing number of published genomes may greatly enhance the current applications of microsatellites by turning them from anonymous to info...

Long-term success of conservation in protected areas requires the cooperation and participation from local people, especially in developing countries where local people often endure most of the cost from human-wildlife conflict. This study investigated crop damage due to wildlife in Thanapati Village adjacent to Shivapuri Nagarjun National Park, Ne...

Trophic cascades play a crucial role in ecosystem functioning. In this study, we tested the effects of avian predation on willows (Salix warburgii) and associated arthropods in an urban wetland. We excluded birds by netting around willow branches for 20 months from September-November 2010 to June 2012. We compared the leaf count, leaf area, leaf bi...

The expansion of agriculture to rugged mountains can exacerbate negative impacts of agricultural activities on ecosystem function. In this study, we monitored streamwater and rainfall chemistry of mountain watersheds at the Feitsui Reservoir Watershed in northern Taiwan to examine the effects of agriculture on watershed nutrient cycling. We found t...

Parasites can generate complex life history trade-offs in a host. In this study, we experimentally reduced the infection level of intestinal helminth parasites in the Taiwan field mouse (Apodemus semotus) to test (1) whether parasite richness and load are biased towards male or female mice (sex-biased parasitism) and (2) whether the effects of para...

Niche evolution underpins the generation and maintenance of biological diversity, but niche conservatism, in which niches remain little changed over time in closely related taxa, and the role of ecology in niche evolution are continually debated. To test whether climate niches are conserved in two closely related passerines in East Asia – the vinou...

The effects of parasitism on host survival and reproduction can be highly complex depending on the type of parasites, host sex and life-history characteristics, and ecological conditions. In this study, we tested sex-biased parasitism from Trombiculid mites (Acarina: Trombiculidae) and their sex-specific effects on host reproduction and survival, i...

Significance The number of passenger pigeons went from billions to zero in mere decades, in contrast to conventional wisdom that enormous population size provides a buffer against extinction. Our understanding of the passenger pigeon’s extinction, however, has been limited by a lack of knowledge of its long-term population history. Here we use both...

To reexamine genetic divergence of Apodemus agrarius in insular Taiwan and the Korean Jeju from other populations in continental Eurasia, we obtained 91 cytochrome b complete sequences of A. agrarius across Eurasia, and these sequences were compared to eight corresponding sequences of A. agrarius, obtained from GenBank. We first found that the two...

Hypothesis: Individuals that diverge from their population's mean trophic niche suffer reduced survival. Organism: The Taiwan field mouse, Apodemus semotus, a common, small, omnivorous rodent. Field site: Pinus-Alnus-Quercus forest in central Taiwan (121°18E, 24°21N). Methods: We used capture-recapture data to measure the survival of individual Apo...

The niche variation hypothesis ( NVH ) predicts that populations with wider niches are phenotypically more variable than populations with narrower niches, which is frequently used to explain diversifying processes such as ecological release. However, not all empirical evidence supports the NVH . Furthermore, a relationship between population phenot...

Chinese fir (Cunninghamia lanceolata) is the most important forest plantation species in subtropical Asia and is rapidly replacing natural forests. Such land-use change may affect ecosystem nutrient cycling through changes in litterfall nutrient flux. Tropical cyclones often cause pulses of litterfall. Previous studies, however, have mostly focused...

Background/Question/Methods The niche variation hypothesis (NVH) predicts that populations with wider niches are more variable than populations with narrower niches, which is frequently used to explain diversifying processes such as ecological release. However, empirical evidence for NVH remains divided. Furthermore, an apparent relationship betw...

Heterozygosity-fitness correlations (HFCs) provide insights into the genetic bases of individual fitness variation in natural populations. However, despite decades of study, the biological significance of HFCs is still under debate. In this study, we investigated HFCs in a large population of the sexually dimorphic lizard (Lacertidae). Because of t...

Locus name, repeat motif, primer sequences, allele sizes (bp), annealing temperature ( T a), number of alleles, observed heterozygosity ( Ho ), expected heterozygosity ( HE ), and statistics of hardy-weinberg equilibrium (HWE) of the 10 microsatellite loci used in this study. (DOC)

Comparison of 16 Cormack-Jolly-Seber models for Takydromus viridipunctatus . (DOC)

Background/Question/Methods Food webs play a crucial role in community and ecosystem ecology. Previous studies have shown that both direct and indirect trophic interactions can be important in maintaining food web dynamics. Trophic cascade, in particular, has been found to occur in a variety of communities and ecosystems. For example, trophic cas...

Background/Question/Methods Species range represents ecological niche of a species, and is determined by abiotic and biotic factors, such as climate, population demography, and interactions with other species. Although interspecific competition could be an important biotic factor determining the range of a species, it is difficult to ascertain whe...

Background/Question/Methods The niche concept is important in almost every level of ecological organizations, from individual behaviors to ecosystem functioning. However, the position and width of the niche in many species can be adjusted in response to changes in resource, competition, and predation. This increases the difficulties in studying n...

The isotope values and elemental concentrations of the dietary sources used in the mixing models. Grid-specific values of δ13C, δ15N, %C, and %N for the fungi/detritivores, above-ground arthropods, plants, millet seeds, and cicadas. The mean value for each dietary source was calculated from taxon-specific values listed in Table S1. (DOC)

The isotope values and elemental concentrations of the plants, arthropods, and fungi included in the study. Taxon-specific values of δ13C, δ15N, %C, and %N for the plants, arthropods, and fungi used in calculating dietary source values. “N” is the number of individual samples included for each taxon. (DOC)

Trophic shifts of generalist consumers can have broad food-web and biodiversity consequences through altered trophic flows and vertical diversity. Previous studies have used trophic shifts as indicators of food-web responses to perturbations, such as species invasion, and spatial or temporal subsidies. Resource pulses, as a form of temporal subsidi...

Background/Question/Methods Consumer assemblages are strongly affected by the availability of food resources. In recent years, more and more studies have shown that, in addition to background resource fluctuations, pulsed resources are also ubiquitous in ecosystems and could potentially have profound ecological consequences in consumer-resource d...

Relationships to 15N abundances have been found in aridity, rainfall, soil age and latitudinal gradients across large spatial and temporal scales and patterns at intermediate spatial and temporal scale remain unclear. An investigation on 15N abundances at intermediate spatial and temporal scale was conducted in a series of successional fields (Blan...

Dietary shifts are commonly exhibited by omnivorous consumers when foraging from variable food resources. One advantage of dietary shifts for a consumer is the ability to gain complementary resources from different foods. In addition, dietary shifts often affect food-web dynamics. Despite the importance of dietary shifts to organismal, community, a...

Food availability often drives consumer population dynamics. However, food availability may also influence capture probability, which if not accounted for may create bias in estimating consumer abundance and confound the effects of food availability on consumer population dynamics. This study compared two commonly used abundance indices (minimum nu...