Sympatric Rodent Species Research Articles

Differentiating Footprints of Sympatric Rodents in Coastal Dune Communities: Implications for Imperiled Beach Mice

AbstractIdentifying techniques for conducting frequent, effective, and inexpensive monitoring of small mammals can be challenging. Traditional approaches such as livetrapping can be laborious, expensive, detrimental to animal health, and ineffective. Passive approaches such as tracking (e.g., from tracks on the ground or footprints collected at a tracking station) have been shown to lessen those burdens, but a problem with tracking, particularly for rodents, is the uncertainty in identifying species from footprints. To address the need for a more accurate method of identifying small mammal tracks, we measured footprints from live-captured rodents and developed a classification tree for distinguishing between subspecies and species using footprint widths treated as having known or unknown identification. We captured rodents within or near the coastal dunes of Florida and Alabama with a focus on areas occupied by threatened and endangered beach mice Peromyscus polionotus subspp., whose populations warrant regular monitoring but whose tracks are not easily distinguished from those of some sympatric species. We measured 6,996 front and hind footprints from 540 individuals across eight species. The overall accuracy of our classification tree was 82.6% and we achieved this using only the front footprint width. Footprint width cutoffs for species identification were < 5.5 mm for house mice Mus musculus, 5.5–6.7 mm for beach mice, and 6.7–8.3 mm for cotton mice Peromyscus gossypinus. We were most successful in confirming the identity of beach mice: we correctly classified approximately 94% of beach mice, while we misclassified fewer than 6% as house mice and fewer than 1% as cotton mice. When we input a beach mouse individual into the classification tree as of an unknown species, we correctly identified 78.1% of individuals as beach mice from their tracks, and most incorrect identifications were of house mouse tracks. Our study demonstrates that researchers can identify sympatric rodent species in coastal dune communities from tracks using quantitative classification based on footprint width. Accurate identification of beach mice or other imperiled species from tracks has important management implications. Not only can wildlife managers determine the presence of a species accurately, but they can monitor populations with considerably less effort than livetrapping requires. Although our study was specific to coastal dune communities, our methods could be adapted for the creation of a classification tree for identifying tracks from suites of species in other areas.

Habitat structure influences refuge use by two sympatric species of Neotropical forest rodents

Habitat structure influences refuge use by two sympatric species of Neotropical forest rodents

Differential seed mass selection on hoarding decisions among three sympatric rodents

Seed mass plays an important role in seed dispersal of many plant species during the hoarding process by rodents. Seeds of a particular plant species are usually dispersed by several sympatric rodent species. However, little is known about seed mass selection by different sympatric rodents that may show different hoarding behavior. In order to understand the role of different rodent species on the evolution of seed mass, we investigated the hoarding behavior and seed mass selection by three sympatric rodents (red spiny rat Maxomys surifer, Chinese white-bellied rat Niviventer confucianus, and yellow-bellied rat Rattus flavipectus) in semi-natural enclosures in southwest China. The hoarding behavior differed significantly among species: M. surifer showed predominantly scatter-hoarding behavior, N. confucianus showed both scatter- and larder-hoarding behavior, and R. flavipectus showed predominantly larder-hoarding behavior. All three rodent species preferred to remove and larder-hoard heavy seeds, but M. surifer and R. flavipectus were more selective on seed mass than N. confucianus during seed removal, while R. flavipectus were more selective than M. surifer and N. confucianus during larder-hoarding. The rodents showed contrasting preferences for seed mass during scatter-hoarding process. M. surifer and N. confucianus preferred to scatter-hoard heavy seeds, whereas R. flavipectus preferred to scatter-hoard light seeds. Our results show that different rodents may exert different selective pressures on seed mass during different dispersal processes. Changes in the composition of rodent communities, including those caused by human disturbance such as forest fragmentation, may influence the fates of seeds with different mass and the evolution of seed mass. Seed mass plays an important role in seed dispersal of many plants by scatter-hoarding rodents. Previous studies usually focus on seed-mass selection by the whole rodent community while ignore the interspecific variation; and they often obtain inconsistent results. By using the semi-natural enclosure, we detected differences in hoarding behaviors among sympatric rodent species, and their different preferences on seed mass. These different preferences may exert different selective pressures on seed mass. Changes in the composition of rodent communities may influence the fates of seeds with different mass and the evolution of seed mass. We suggest that differences in hoarding behavior among sympatric rodent species should be considered in future field studies, as this will help us to better understand the role of the whole rodent community in the evolution of seed mass of forest trees that depend on dispersal by rodents.

Body size, not phylogenetic relationship or residency, drives interspecific dominance in a little pocket mouse community

The role of interspecific aggression in structuring ecological communities can be important to consider when reintroducing endangered species to areas of their historic range that are occupied by competitors. We sought to determine which species is the most serious interference competitor of the endangered Pacific pocket mouse, Perognathus longimembris pacificus, and more generally, whether interspecific aggression in rodents is predicted by body size, residency status or phylogenetic relatedness. We carried out simulated territory intrusion experiments between P. longimembris and four sympatric species of rodents (Chaetodipus fallax, Dipodomys simulans, Peromyscus maniculatus, Reithrodontomys megalotis) in a field enclosure in southern California sage scrub habitat. We found that body size asymmetries strongly predicted dominance, regardless of phylogenetic relatedness or the residency status of the individuals. The largest species, D. simulans, was the most dominant while the smallest species, R. megalotis, was the least dominant to P. longimembris. Furthermore, P. longimembris actively avoided encounters with all species, except R. megalotis. One management recommendation that follows from these results is that P. longimembris should not be reintroduced to areas with high densities of D. simulans until further research is carried out to assess the fitness consequences of the interactions. Our finding that the species least similar in body size is the most serious interference competitor of P. longimembris highlights an important distinction between interference and exploitative competition in rodent communities.

Age and habitat quality matters: isotopic variation of two sympatric species of rodents in Neotropical Forest

Dietary studies allow us to understand important ecological patterns such as intra- and interpopulation variation and interspecific differences regarding the use of food sources. Stable isotopes have been successfully employed to detect dietary differences between species and feeding shifts within a species, as a result of function of age, habitat use, and resource availability. Here we investigated the stable isotope compositions of carbon and nitrogen of young and adult specimens of Euryoryzomys russatus and Sooretamys angouya and their stomach contents, in a complex mosaic of vegetation in the Atlantic Forest. Isotopes indicated a pronounced inter- and intraspecific plasticity in resource use between E. russatus and S. angouya . Plant sources was the prevalent feeding habit for E. russatus , with small to intermediate consumption of arthropods. For S. angouya , plants were dominant in the stomach content, but arthropod arose as an important source. E. russatus showed more isotope signature variation between grids than S. angouya , suggesting that the former was more affected by habitat changes. These results allow us to better understand the ontogeny, diet and the behavioral responses to environmental variations of both species. Finally, our study contributes to reduce the lack of knowledge about sympatric species ecology and aggregates information for their conservation.

Does scatter-hoarding of seeds benefit cache owners or pilferers?

The scatter‐hoarding behavior of granivorous rodents plays an important role in seed dispersal and seedling regeneration of trees, as well as the evolution of several well‐known mutualisms between trees and rodents in forest ecosystems. Because it is difficult to identify seed hoarders and pilferers under field conditions by traditional methods, the full costs incurred and benefits accrued by scatter‐hoarding have not been fully evaluated in most systems. By using infrared radiation camera tracking and seed tagging, we investigated the benefits and losses of scatter‐hoarded seeds (Camellia oleifera) for 3 sympatric rodent species (Apodemus draco, Niviventer confucianus and Leopoldamys edwardsi) in a subtropical forest of Southwest China during 2013 to 2015. We established the relationships between the rodents and the seeds at the individual level. For each rodent species, we calculated the cache recovery rate of cache owners, as well as conspecific and interspecific pilferage rates. We found that all 3 sympatric rodent species had a cache recovery advantage with rates that far exceeded average pilferage rates over a 30‐day tracking period. The smallest species (A. draco) showed the highest rate of scatter‐hoarding and the highest recovery advantage compared with the other 2 larger species (N. confucianus and L. edwardsi). Our results suggest that scatter‐hoarding benefits cache owners in food competition, supporting the pilferage avoidance hypothesis. Therefore, scatter‐hoarding behavior should be favored by natural selection, and plays a significant role in species coexistence of rodent community and in the formation of mutualism between seeds and rodents in forest ecosystems.

Unpredictability of escape trajectory explains predator evasion ability and microhabitat preference of desert rodents

Mechanistically linking movement behaviors and ecology is key to understanding the adaptive evolution of locomotion. Predator evasion, a behavior that enhances fitness, may depend upon short bursts or complex patterns of locomotion. However, such movements are poorly characterized by existing biomechanical metrics. We present methods based on the entropy measure of randomness from Information Theory to quantitatively characterize the unpredictability of non-steady-state locomotion. We then apply the method by examining sympatric rodent species whose escape trajectories differ in dimensionality. Unlike the speed-regulated gait use of cursorial animals to enhance locomotor economy, bipedal jerboa (family Dipodidae) gait transitions likely enhance maneuverability. In field-based observations, jerboa trajectories are significantly less predictable than those of quadrupedal rodents, likely increasing predator evasion ability. Consistent with this hypothesis, jerboas exhibit lower anxiety in open fields than quadrupedal rodents, a behavior that varies inversely with predator evasion ability. Our unpredictability metric expands the scope of quantitative biomechanical studies to include non-steady-state locomotion in a variety of evolutionary and ecologically significant contexts.

Helminth composition and prevalence of indigenous and invasive synanthropic murid rodents in urban areas of Gauteng Province, South Africa.

Although synanthropic rodents such as the indigenous species, Mastomys coucha, and the invasive species, Rattus norvegicus, R. rattus and R. tanezumi, are well-known to be hosts to various micro- and macroparasites, their helminth parasite fauna is poorly studied in South Africa. In an attempt to remedy the situation, the aim of the present study was to investigate the helminth fauna of these sympatric rodent species, which were obtained from the informal settlements of Alexandra, Tembisa, Diepsloot and residential suburbs of Pretoria and Hammanskraal, Gauteng Province, South Africa. Helminths were recovered from the urinary bladder, liver and gastrointestinal tract and were identified morphologically and molecularly. The recovered nematodes were all rodent-specific and included Aspiculuris tetraptera, Eucoleus sp., Heterakis spumosa, Mastophorus muris, Nippostrongylus brasiliensis, Protospirura sp., Strongyloides ratti, Syphacia obvelata, Syphacia muris, Trichuris sp. and Trichosomoides crassicauda. Syphacia obvelata, a commensal nematode of laboratory rodents, was recovered from indigenous M. coucha. Strobilar stages of cestodes recovered included Hymenolepis diminuta, Hymenolepis nana and Inermicapsifer madagascariensis. Recovered metacestodes were strobilocerci of Hydatigera taeniaeformis from all three invasive Rattus species and coenurostrobilocerci of Hydatigera parva from M. coucha. An acanthocephalan, Moniliformis moniliformis, was recovered from R. rattus only. All rodent species examined showed high helminth infection prevalence (≥70%) with equal or higher nematode than cestode prevalence. Mastomys coucha, however, showed significantly lower cestode prevalence than Rattus species where they co-occur. Interspecific transmission of helminths likely occurs between invasive and indigenous rodents, and these rodents harbour several helminths that have zoonotic implications.

Quantifying whether different demographic models produce incongruent results on population dynamics of two long-term studied rodent species

Abstract1. Population density (ind/ha) of long-term (>15 years) series of CMR populations, using distinct demographic models designed for both open and closed populations, were analysed for two sympatric species of rodents (Myodes glareolus and Apodemus flavicollis) from a mountain area in central Italy, in order to test the relative performance of various employed demographic models. In particular, the hypothesis that enumeration models systematically underestimate the population size of a given population was tested.2. Overall, we compared the performance of 7 distinct demographic models, including both closed and open models, for each study species. Although the two species revealed remarkable intrinsic differences in demography traits (for instance, a lower propensity for being recaptured in Apodemus flavicollis), the Robust Design appeared to be the best fitting model, showing that it is the most suitable model for long-term studies.3. Among the various analysed demographic models, Jolly-Seber returned the lower estimates of population density for both species. Thus, this demographic model could not be suggested for being applied for long-term studies of small mammal populations because it tends to remarkably underestimate the effective population size. Nonetheless, yearly estimates of population density by Jolly-Seber correlated positively with yearly estimates of population density by closed population models, thus showing that interannual trends in population dynamics were uncovered by both types of demographic models, although with different values in terms of true population size.

Different population responses of three sympatric rodent species to acorn masting—the role of tannin tolerance

AbstractRodent population dynamics are predicted to respond positively to the masting of acorns, but diverging results have been published. This study tested the hypothesis that population responses to acorn masting vary depending on differences in the tolerance to tannins of different rodent species. The effects of acorn abundance on the rodent population densities were analyzed using a dataset obtained in Hokkaido, Japan. Specifically, population fluctuations of three rodent species (Apodemus speciosus, A. argenteus, and Myodes rufocanus) and the abundance of Quercus crispula acorns have been monitored since 1992. Acorn production in previous years had a positive effect on the annual population growth rates of A. speciosus; however, this trend was not clear in the other two species. Tannin tolerance, assessed by body weight changes in an acorn feeding experiment, exhibited clear differences among the rodent species; namely, the body weight of A. speciosus increased, whereas that of the other two species decreased. The observed responses to acorn masting of populations of the three sympatric rodent species reflected tannin tolerance. It suggests that only populations of species with high tannin tolerance positively respond to acorn masting. Previous studies tend to overlook species‐specific abilities of coping with tannins in acorns. Our results emphasize the necessity of evaluating the tannin tolerance of rodents and the tannin content of acorns to understand how rodent population dynamics and acorn production are related.

Establishing species-specific sexing markers suitable for non-invasive samples of species lacking genomic resources: an example using the highly endangered common hamster Cricetus cricetus

Here we present an approach to establish species-specific genetic markers for sex identification suitable for non-invasive samples. Such markers are not yet available for the endangered common hamster (Cricetus cricetus) because of the lack of genomic resources. Using Y chromosome conserved anchored tagged sequences (YCATS) exonic primers, we obtained Y-chromosomal sequences from hamsters and sympatric rodent species. From this, we designed hamster-specific primers targeting two short Y-chromosomal intron fragments and included them in microsatellite multiplex reactions, using autosomal loci also as amplification controls. The method yielded highly consistent results. The approach can be easily applied to development of sex markers in species for which there are no genome sequences available and thus aid conservation genetics efforts.

Forecasting potential emergence of zoonotic diseases in South‐East Asia: network analysis identifies key rodent hosts

Summary Within complex ecological systems, identifying animal species likely to play a key role in the emergence of infectious zoonotic diseases remains a major challenge. One approach consists of using information on current ecological and parasitological similarities among host species in order to predict the most likely pathways for future pathogen spillover. Using field data acquired from 15 sympatric rodent species in various habitats in Thailand, Cambodia and Laos, we built networks based on shared parasites (17 helminth and 15 microparasite species) and shared habitats among rodent species and humans. We investigated the architectures of bipartite and unipartite networks using modularity, subgroups partitioning or node centrality, to assess the relative epidemiological importance of particular rodent species. Our results showed that Rattus tanezumi, Bandicota savilei and R. exulans were consistently found to be members of subgroups that included humans in unipartite and bipartite networks on zoonotic agents and shared habitats. High values of centrality in shared zoonotic agents were found for the same three rodent species, whereas high values of shared habitats were observed for two of them. Although phylogenetically related rodent species likely shared both habitats and parasites, a lack of habitat specialization was associated with increased zoonotic parasite sharing. Our results emphasize the disproportionate importance of these three rodent species, through their high degree of connectivity with humans, which may represent a high risk for direct zoonotic spillover. Moreover, due to its high centrality in habitats, R. tanezumi may also play a key role as a bridge host. The recent discovery of new arenaviruses in rodents in South‐East Asia, with associated disease in humans in Cambodia, provides an opportunity to test this empirically. The three rodent species identified using our network approach are some of the potential maintenance hosts for these new emerging arenaviruses. Synthesis and applications. Our results on rodents and their pathogens in South‐East Asia show that network analysis has a high potential to improve the surveillance of emerging zoonotic pathogens by targeting key host species and potential ‘emerging’ pathogen–rodent interactions in complex and heterogeneous landscapes.

Habitat selection by two sympatric rodent species in an alpine resort

Conservation of small mammal species relies on an understanding of their habitat use. We used trapping surveys and telemetry to examine habitat selection and use by the broad-toothed rat (Mastacomys fuscus mordicus) and the bush rat (Rattus fuscipes) in an alpine resort in Victoria. M. fuscus occurred at low numbers, nesting in subalpine wet heathland and foraging in that habitat as well as small patches of disturbed woodland. In contrast, R. fuscipes was more common and nested in woodlands. Although foraging primarily in woodlands, R. fuscipes also foraged in all other available habitats. Both species showed strong selection for woodland fragments within ski runs. Although highly disturbed, these habitats may provide important habitat and connectivity between less disturbed and larger habitat patches.

Aggressive and investigative behaviors of two sympatric species of echimyid rodents, Proechimys semispinosus and Hoplomys gymnurus, in Central Panama

An understanding of the mechanisms that allow ecologically similar species to coexist is critical in making effective conservation and restoration decisions. This understanding is especially important when considering species that play critical roles in forest regeneration. Small mammals influence Neotropical forest regeneration following disturbance through their actions as seed dispersers and seed predators. In Panama, the Central American spiny rat (Proechimys semispinosus) and the armored rat (Hoplomys gymnurus) persist sympatrically despite a similar diet and seasonal food resource limitation. To study the relationship between these species, we conducted behavioral arena trials to analyze interspecific and intraspecific interactions. Our goal was to determine whether behavioral dominance between H. gymnurus and P. semispinosus exists, potentially reducing the intensity of aggressive competition and allowing the two species to coexist sympatrically. Aggression data were analyzed using a zero-inflated negative binomial regression model showing that species pairing was a significant predictor of aggression, supporting the existence of behavioral dominance by P. semispinosus over H. gymnurus. Investigative behavior data were analyzed using the Kruskal–Wallis test and showed a significantly higher level of investigative behavior for P. semispinosus towards H. gymnurus during the dry season when resources are scarce compared to the wet season when resources are plentiful.

Coupled biotopic variation in populations of sympatric rodent species in the Southern Urals

Using geometric morphometric methods, coupled biotopic variation in the shape of the mandible was revealed in cenopopulations of two sympatric rodent species, the pygmy wood mouse (Sylvaemus uralensis Pall., 1811) and bank vole (Myodes glareolus Schreb., 1780), in the Southern Urals. As a rule, heterospecific pairs from syntopic samples synchronously taken in cenopopulations of the two species inhabiting contrasting local biotopes displayed similar (parallel and unidirectional) morphological changes. In an unusually arid year, however, differently directed morphogenetic responses were revealed in young of the year from cenopopulations of the two species in broadleaf forest outliers surrounded by steppe vegetation on tops of the Guberlya low hills. Such a local disturbance of the coupled pattern of biotopic variation in S. uralensis and M. glareolus cenopopulations under ambient conditions sharply deviating from the optimum may be evidence for depletion of their coevolutionary adaptive potential, which is estimated from the range of ecological conditions at which parallelism in the variation of sympatric species is observed.

Mutualistic and predatory interactions are driven by rodent body size and seed traits in a rodent–seed system in warm-temperate forest in northern China

Context Mutualistic interactions between animals and plants shape the structure of plant–animal systems and, subsequently, affect plant-community structure and regeneration. Aims To assess the effects of plant and rodent functional traits on the formation of mutualistic and predatory interactions regarding seed dispersal and predation in a warm-temperate forest. Methods Seed scatter-hoarding and predation by six sympatric rodent species on seeds belonging to five sympatric tree species were tested under enclosure conditions. Key results Functional traits (i.e. rodent body size and seed traits) are important to mutualism/predation in this seed–rodent system. The rodent–seed network is highly nested: large-sized rodents have mutualistic or predatory interactions with both large- and small-sized seed species, but small-sized rodents interacted with small-sized seed species only. Large seeds or seeds with hard coats enhanced mutualism and reduced predation. Conclusion Body size of rodents and seed traits such as handling time and nutritional value are key factors in the formation of mutualistic and predatory interactions within seed–rodent systems. Implications To promote seedling establishment in degenerated forests, introducing or protecting large-sized scatter hoarders and reducing the density of pure seed eaters are needed.

Seasonal flooding regime and ecological traits influence genetic structure of two small rodents.

Although codistributed species are affected by the same abiotic factors, such as rivers and seasonal flooding regimes, ecological traits, such as locomotion habits and habitat preferences, may also influence differences in levels of genetic diversity and differentiation. We examined population genetic structure and diversity of Hylaeamys megacephalus and Oecomys aff. roberti, two cricetid rodent species from the mid-Araguaia River in central Brazil, using mitochondrial DNA sequence data. Specifically, we aim to test whether the Araguaia River acts as a barrier to the gene flow of these two species and to assess how ecological traits, such as locomotion habits and habitat preferences, may influence differences in levels of genetic diversity and differentiation. As both species occur in flooded forests, neither showed genetic differences related to river banks. Oecomys aff. roberti showed stronger population structure that appears to be associated with isolation by distance. This arboreal species maintained stable populations in the Araguaia River, while the terrestrial H. megacephalus was more affected by seasonal floods, resulting in a genetic signature of population expansion. Our initial predictions were largely supported by our results given that locomotion habits and habitat preferences of each species appears to have played a role on the genetic structure of these two sympatric rodent species.

Diversification of an emerging pathogen in a biodiversity hotspot: Leptospira in endemic small mammals of Madagascar.

Biodiversity hotspots and associated endemism are ideal systems for the study of parasite diversity within host communities. Here, we investigated the ecological and evolutionary forces acting on the diversification of an emerging bacterial pathogen, Leptospira spp., in communities of endemic Malagasy small mammals. We determined the infection rate with pathogenic Leptospira in 20 species of sympatric rodents (subfamily Nesomyinae) and tenrecids (family Tenrecidae) at two eastern humid forest localities. A multilocus genotyping analysis allowed the characterization of bacterial diversity within small mammals and gave insights into their genetic relationships with Leptospira infecting endemic Malagasy bats (family Miniopteridae and Vespertilionidae). We report for the first time the presence of pathogenic Leptospira in Malagasy endemic small mammals, with an overall prevalence of 13%. In addition, these hosts harbour species of Leptospira (L. kirschneri, L. borgpetersenii and L. borgpetersenii group B) which are different from those reported in introduced rats (L. interrogans) on Madagascar. The diversification of Leptospira on Madagascar can be traced millions of years into evolutionary history, resulting in the divergence of endemic lineages and strong host specificity. These observations are discussed in relation to the relative roles of endemic vs. introduced mammal species in the evolution and epidemiology of Leptospira on Madagascar, specifically how biodiversity and biogeographical processes can shape community ecology of an emerging pathogen and lead to its diversification within native animal communities.

Long‐term seed survival and dispersal dynamics in a rodent‐dispersed tree: testing the predator satiation hypothesis and the predator dispersal hypothesis

Summary Mast seeding in animal‐dispersed plants has previously been accounted for by two main hypotheses: the predator satiation hypothesis (that it increases seed survival and establishment before dispersal) and the predator dispersal hypothesis (that it increases seed dispersal or dispersal distance). However, neither hypothesis has been rigorously tested with simultaneous data on seed production, seed predation and seed dispersal by vertebrate seed predators. We studied oil tea Camellia oleifera (Theaceae) seed production for eight years (2002–2009) in a subtropical forest in south‐west China, and investigated how annual seed and rodent abundance determined per capita seed availability for rodent seed predators and seed dispersers and how seed and rodent abundance were related to seed dispersal and seed survival via scatter‐hoarding. We predicted the patterns of seed dispersal and survival to test the two hypotheses about mast seeding. Edward's long‐tailed rat Leopoldamys edwardsi acted as the principal seed disperser of oil tea seeds because of scatter‐hoarding, while other sympatric rodent species acted only as seed predators. We first provided a reasonable method to estimate per capita seed availability based on annual seed abundance and annual metabolic rodent abundance (corrected for metabolic‐scaling body mass of each rodent species). We found that annual seed abundance, annual metabolic rodent abundance and per capita seed availability all had some significant effects on different estimators of seed fates (including dispersal distances) across each stage from seedfall to seedling establishment. Both annual seed abundance and per capita seed availability were positively correlated with pre‐dispersal seed survival, but negatively correlated with scatter‐hoarding (and recaching), seed survival after dispersal and dispersal distances. However, annual metabolic rodent abundance had a positive effect on scatter‐hoarding, but had a negative effect on the time to cache recovery. Synthesis. Since greater seed production was associated with improvement in pre‐dispersal survival of oil tea seeds but a reduction in dispersal (including secondary dispersal and dispersal distance), our long‐term study indicates that, compared with the predator dispersal hypothesis, the predator satiation hypothesis provides a better mechanism predicting seed dispersal and seed survival in animal‐dispersed plants by integrating seed abundance and animal abundance.

Seed caching and cache pilferage by three rodent species in a temperate forest in the Xiaoxinganling Mountains

Although differences in food-hoarding tactics both reflect a behavioral response to cache pilferage among rodent species and may help explain their coexistence, differentiation in cache pilfering abilities among sympatric rodents with different hoarding strategies is seldom addressed. We carried out semi-natural enclosure experiments to investigate seed hoarding tactics among three sympatric rodent species (Tamias sibiricus, Apodemus peninsulae and Clethrionomys rufocanus) and the relationship of their pilfering abilities at the inter- and intraspecific levels. Our results showed that T. sibiricus exhibited a relatively stronger pilfering ability than A. peninsulae and C. rufocanus, as indicated by its higher recovery rate of artificial caches. Meanwhile A. peninsulae showed a medium pilfering ability and C. rufocanus displayed the lowest ability. We also noted that both cache size and cache depth significantly affected cache recovery in all three species. T. sibiricus scatter-hoarded more seeds than it larder-hoarded, A. peninsulae larder-hoarded more than scatter-hoarded, and C. rufocanus acted as a pure larder-hoarder. In T. sibiricus, individuals with lower pilfering abilities tended to scatter hoard seeds, indicating an intraspecific variation in hoarding propensity. Collectively, these results indicated that sympatric rodent species seem to deploy different food hoarding tactics that allow their coexistence in the temperate forests, suggesting a strong connection between hoarding strategy and pilfering ability.