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1.
The seed dispersal mechanisms and regeneration of various forest ecosystems can benefit from the actions of carnivores via endozoochory. This study was aimed to evaluate the role of carnivores in endozoochory and diploendozoochory, as well as their effect on seed viability, scarification, and germination in two forest ecosystems: temperate and tropical dry forest. We collected carnivore scat in the Protected Natural Area of Sierra Fría in Aguascalientes, Mexico, for 2 years to determine the abundance and richness of seeds dispersed by each carnivore species, through scat analysis. We assessed seed viability through optical densitometry using X‐rays, analyzed seed scarification by measuring seed coat thickness using a scanning electron microscope, and evaluated seed germination in an experiment as the percentage of seeds germinated per carnivore disperser, plant species, and forest type. In the temperate forest, four plant species (but mainly Arctostaphylos pungens) were dispersed by four mammal species. The gray fox dispersed the highest average number of seeds per scat (66.8 seeds). Bobcat dispersed seeds through diploendozoochory, which was inferred from rabbit (Sylvilagus floridanus) hair detected in their scats. The tropical dry forest presented higher abundance of seeds and richness of dispersed plant species (four species) than in the temperate forest, and the coati dispersed the highest number of seeds (8,639 seeds). Endozoochory and diploendozoochory did not affect viability in thick‐testa seeds (1,480 µm) in temperate forest and thin‐testa seeds (281 µm) in tropical dry forest. Endozoochory improved the selective germination of seeds. Nine plant species were dispersed by endozoochory, but only one species (Juniperus sp.) by diploendozoochory. These results suggest that carnivores can perform an important ecological function by dispersing a great abundance of seeds, scarifying these seeds causing the formation of holes and cracks in the testas without affecting viability, and promoting the selective germination of seeds.  相似文献   

2.
3.
Large carnivore feeding ecology plays a crucial role for management and conservation for predators and their prey. One of the keys to this kind of research is to identify the species composition in the predator diet, for example, prey determination from scat content. DNA‐based methods applied to detect prey in predators’ scats are viable alternatives to traditional macroscopic approaches, showing an increased reliability and higher prey detection rate. Here, we developed a molecular method for prey species identification in wolf (Canis lupus) scats using multiple species‐specific marker loci on the cytochrome b gene for 18 target species. The final panel consisted of 80 assays, with a minimum of four markers per target species, and that amplified specifically when using a high‐throughput Nanofluidic array technology (Fluidigm Inc.). As a practical example, we applied the method to identify target prey species DNA in 80 wolf scats collected in Sweden. Depending on the number of amplifying markers required to obtain a positive species call in a scat, the success in determining at least one prey species from the scats ranged from 44% to 92%. Although we highlight the need to evaluate the optimal number of markers for sensitive target species detection, the developed method is a fast and cost‐efficient tool for prey identification in wolf scats and it also has the potential to be further developed and applied to other areas and large carnivores as well.  相似文献   

4.
Large carnivores play an important role in the functioning of ecosystems, yet their conservation remains a massive challenge across the world. Owing to wide‐ranging habits, they encounter various anthropogenic pressures, affecting their movement in different landscape. Therefore, studying how large carnivores adapt their movement to dynamic landscape conditions is vital for management and conservation policy.A total of 26 individuals across 4 species of large carnivores of different sex and age classes (14 Panthera tigris, 3 Panthera pardus, 5 Cuon alpinus, and 4 Canis lupus pallipes) were GPS collared and monitored from 2014–19. We quantified movement parameters (step length and net squared displacement) of four large carnivores in and outside protected areas in India. We tested the effects of human pressures such as human density, road network, and landuse types on the movement of the species. We also examined the configuration of core areas as a strategy to subsist in a human‐dominated landscape using BBMM.Mean displacement of large carnivores varied from 99.35 m/hr for leopards to 637.7 m/hr for wolves. Tigers outside PAs exhibited higher displacement than tigers inside PAs. Moreover, displacement during day–night was significantly different for tigers inside and outside PAs. Similarly, wolf also showed significant difference between day‐night movement. However, no difference in day–night movement was found for leopard and dholes. Anthropogenic factors such as road length and proportion of agriculture within the home range of tigers outside PAs were found to be significantly different. All the habitat variables in the home range showed significant difference between the social canids. The core area size for tiger outside PA and wolf was found greater than PAs.The study on movement of large carnivore species across landscapes is crucial for conservation planning. Our findings can be a starting point for interlinking animal movement and landscape management of large carnivore conservation in the current Anthropocene.  相似文献   

5.
Pollinator behavior is an important contributor to plants speciation, yet how variation in pollinator behavior causes variation in reproductive isolation (RI) is largely uncharacterized. Here I present a model that predicts how two aspects of pollinator behavior, constancy and preference, contribute to a barrier to reproduction in plants. This model is motivated by two observations: most co‐occurring plants vary in frequency over space and time, and most plants have multiple pollinators that differ in behavior. Thus, my goal was to understand how relative frequencies of plants and pollinators in a community influence ethological RI between co‐occurring plants. I find that RI for a focal plant generally increases with increasing relative plant frequency, but the shape of this relationship is highly dependent on the strength of pollinator behavior (constancy and preference). Additionally, when multiple pollinators express different behavior, I find that pollinators with stronger preference disproportionately influence RI. But, I show that RI caused by constancy is the average RI predicted from constancy of each pollinator weighted by pollinator frequency. I apply this model to examples of pollinator‐mediated RI in Phlox and in Ipomopsis to predict the relationships between plant frequency and ethological RI in natural systems. This model provides new insights into how and why pollinator specialization causes RI, and how RI could change with changing biological communities.  相似文献   

6.
  • 1 We reviewed patterns of fruit consumption amongst 10 species of mesocarnivores: red fox Vulpes vulpes, weasel Mustela nivalis, stoat Mustela erminea, polecat Mustela putorius, stone marten Martes foina, pine marten Martes martes, Eurasian badger Meles meles, common genet Genetta genetta, Egyptian mongoose Herpestes ichneumon and wildcat Felis silvestris in Mediterranean Europe.
  • 2 The 65 reviewed studies recorded 79 different fruits eaten by carnivores, 58 of which were identified to species. Most records (63%) were of fleshy fruits with high pulp content. The frequency of occurrence of fruit items varied widely amongst species and regions. Four of the carnivore species (red fox, stone marten, badger and common genet) included more than 30 fruit species in their diet.
  • 3 A longitudinal pattern was detected in the consumption of fruit in the Mediterranean region, with the frequency of occurrence of fruit consumption increasing towards the east.
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7.
Phytolith‐occluded carbon (PhytOC) is an important long‐term stable carbon fraction in grassland ecosystems and plays a promising role in global carbon sequestration. Determination of the PhytOC traits of different plants in major grassland types is crucial for precisely assessing their phytolith carbon sequestration potential. Precipitation is the predominant factor in controlling net primary productivity (NPP) and species composition of the semiarid steppe grasslands. We selected three representative steppe communities of the desert steppe, the dry typical steppe, and the wet typical steppe in Northern Grasslands of China along a precipitation gradient, to investigate their species composition, biomass production, and PhytOC content for quantifying its long‐term carbon sequestration potential. Our results showed that (a) the phytolith and PhytOC contents in plants differed significantly among species, with dominant grass and sedge species having relatively high contents, and the contents are significantly higher in the below‐ than the aboveground parts. (b) The phytolith contents of plant communities were 16.68, 17.94, and 15.85 g/kg in the above‐ and 86.44, 58.73, and 76.94 g/kg in the belowground biomass of the desert steppe, the dry typical steppe, and the wet typical steppe, respectively; and the PhytOC contents were 0.68, 0.48, and 0.59 g/kg in the above‐ and 1.11, 0.72, and 1.02 g/kg in the belowground biomass of the three steppe types. (c) Climatic factors affected phytolith and PhytOC production fluxes of steppe communities mainly through altering plant production, whereas their effects on phytolith and PhytOC contents were relatively small. Our study provides more evidence on the importance of incorporating belowground PhytOC production for estimating phytolith carbon sequestration potential and suggests it crucial to quantify belowground PhytOC production taking into account of plant perenniality and PhytOC deposition over multiple years.  相似文献   

8.
One of the few laws in ecology is that communities consist of few common and many rare taxa. Functional traits may help to identify the underlying mechanisms of this community pattern, since they correlate with different niche dimensions. However, comprehensive studies are missing that investigate the effects of species mean traits (niche position) and intraspecific trait variability (ITV, niche width) on species abundance. In this study, we investigated fragmented dry grasslands to reveal trait‐occurrence relationships in plants at local and regional scales. We predicted that (a) at the local scale, species occurrence is highest for species with intermediate traits, (b) at the regional scale, habitat specialists have a lower species occurrence than generalists, and thus, traits associated with stress‐tolerance have a negative effect on species occurrence, and (c) ITV increases species occurrence irrespective of the scale. We measured three plant functional traits (SLA = specific leaf area, LDMC = leaf dry matter content, plant height) at 21 local dry grassland communities (10 m × 10 m) and analyzed the effect of these traits and their variation on species occurrence. At the local scale, mean LDMC had a positive effect on species occurrence, indicating that stress‐tolerant species are the most abundant rather than species with intermediate traits (hypothesis 1). We found limited support for lower specialist occurrence at the regional scale (hypothesis 2). Further, ITV of LDMC and plant height had a positive effect on local occurrence supporting hypothesis 3. In contrast, at the regional scale, plants with a higher ITV of plant height were less frequent. We found no evidence that the consideration of phylogenetic relationships in our analyses influenced our findings. In conclusion, both species mean traits (in particular LDMC) and ITV were differently related to species occurrence with respect to spatial scale. Therefore, our study underlines the strong scale‐dependency of trait‐abundance relationships.  相似文献   

9.
《农业工程》2023,43(1):99-105
There is a little understanding of how apex carnivores partition their diet to coexist. We studied food habit and trophic niche overlap of two apex carnivores, tiger and leopard in the tropical forest of Similipal tiger reserve, eastern India. We used line transect and scat analysis method, to estimate the prey availability and determine the diet and prey selection of two apex carnivores. Tigers consumed mostly large and medium-sized prey, whereas leopards mostly consumed medium and small-sized prey. Both carnivores were not random in their consumption of prey, sambar and wild pigs were selectively consumed by tigers, whereas leopards selectively consumed wild pigs, barking deer and mouse deer. Dietary overlap between two carnivore species was moderate (Pianka's niche overlap index: 0.55), and trophic niche breadth (Levin's standardized niche breadth) of the leopard (0.52) was greater than that of the tiger (0.37). Overall, tigers exhibited specialized feeding habits, whereas leopards showed generalist feeding habits. Our study highlights the opportunistic nature of leopards and probably a reason for the species successfully coexist with tigers.  相似文献   

10.
Carnivore intraguild dynamics depend on a complex interplay of environmental affinities and interspecific interactions. Context‐dependency is commonly expected with varying suites of interacting species and environmental conditions but seldom empirically described. In South Africa, decentralized approaches to conservation and the resulting multi‐tenure conservation landscapes have markedly altered the environmental stage that shapes the structure of local carnivore assemblages. We explored assemblage‐wide patterns of carnivore spatial (residual occupancy probability) and temporal (diel activity overlap) co‐occurrence across three adjacent wildlife‐oriented management contexts—a provincial protected area, a private ecotourism reserve, and commercial game ranches. We found that carnivores were generally distributed independently across space, but existing spatial dependencies were context‐specific. Spatial overlap was most common in the protected area, where species occur at higher relative abundances, and in game ranches, where predator persecution presumably narrows the scope for spatial asymmetries. In the private reserve, spatial co‐occurrence patterns were more heterogeneous but did not follow a dominance hierarchy associated with higher apex predator densities. Pair‐specific variability suggests that subordinate carnivores may alternate between pre‐emptive behavioral strategies and fine‐scale co‐occurrence with dominant competitors. Consistency in species‐pairs diel activity asynchrony suggested that temporal overlap patterns in our study areas mostly depend on species'' endogenous clock rather than the local context. Collectively, our research highlights the complexity and context‐dependency of guild‐level implications of current management and conservation paradigms; specifically, the unheeded potential for interventions to influence the local network of carnivore interactions with unknown population‐level and cascading effects.  相似文献   

11.
1. Although carnivores indirectly improve plant fitness by decreasing herbivory, they may also decrease plant reproduction by disrupting plant-pollinator mutualism. The overall magnitude of the resulting net effect of carnivores on plant fitness and the factors responsible for the variations in strength and direction of this effect have not been explored quantitatively to date. 2. We performed a meta-analysis of 67 studies containing 163 estimates of the effects of carnivores on plant fitness and examined the relative importance of several potential sources of variation in carnivore effects. 3. Carnivores significantly increased plant fitness via suppression of herbivores and decreased fitness by consuming pollinators. The overall net effect of carnivores on plant fitness was positive (32% increase), indicating that effects via herbivores were stronger than effects via pollinators. 4. Parasitoids had stronger positive effect on plant fitness than predators. Active hunters increased plant fitness, whereas stationary predators had no significant effect, presumably because they were more prone to disrupt plant-pollinator mutualism. Carnivores with broader habitat domain had negative effects on plant fitness, whereas those with narrow habitat domain had positive effects. 5. Predator effects were positive for plants which offered rewards (e.g. extrafloral nectaries) and negative for plants which lacked any attractors. 6. This study adds new knowledge on the factors that determine the strength of terrestrial trophic cascades and highlights the importance of considering simultaneous contrasting interactions in the same study system.  相似文献   

12.
Long‐term biodiversity experiments have shown increasing strengths of biodiversity effects on plant productivity over time. However, little is known about rapid evolutionary processes in response to plant community diversity, which could contribute to explaining the strengthening positive relationship. To address this issue, we performed a transplant experiment with offspring of seeds collected from four grass species in a 14‐year‐old biodiversity experiment (Jena Experiment). We used two‐ and six‐species communities and removed the vegetation of the study plots to exclude plant–plant interactions. In a reciprocal design, we transplanted five “home” phytometers (same origin and actual environment), five “away‐same” phytometers (same species richness of origin and actual environment, but different plant composition), and five “away‐different” phytometers (different species richness of origin and actual environment) of the same species in the study plots. In the establishment year, plants transplanted in home soil produced more shoots than plants in away soil indicating that plant populations at low and high diversity developed differently over time depending on their associated soil community and/or conditions. In the second year, offspring of individuals selected at high diversity generally had a higher performance (biomass production and fitness) than offspring of individuals selected at low diversity, regardless of the transplant environment. This suggests that plants at low and high diversity showed rapid evolutionary responses measurable in their phenotype. Our findings provide first empirical evidence that loss of productivity at low diversity is not only caused by changes in abiotic and biotic conditions but also that plants respond to this by a change in their micro‐evolution. Thus, we conclude that eco‐evolutionary feedbacks of plants at low and high diversity are critical to fully understand why the positive influence of diversity on plant productivity is strengthening through time.  相似文献   

13.
  1. The recovery of terrestrial carnivores in Europe is a conservation success story. Initiatives focused on restoring top predators require information on how resident species may interact with the re‐introduced species as their interactions have the potential to alter food webs, yet such data are scarce for Europe.
  2. In this study, we assessed patterns of occupancy and interactions between three carnivore species in the Romanian Carpathians. Romania houses one of the few intact carnivore guilds in Europe, making it an ideal system to assess intraguild interactions and serve as a guide for reintroductions elsewhere.
  3. We used camera trap data from two seasons in Transylvanian forests to assess occupancy and co‐occurrence of carnivores using multispecies occupancy models.
  4. Mean occupancy in the study area was highest for lynx (Ψwinter = 0.76 95% CI: 0.42–0.92; Ψautumn = 0.71 CI: 0.38–0.84) and wolf (Ψwinter = 0.60 CI: 0.34–0.78; Ψautumn = 0.81 CI: 0.25–0.95) and lowest for wildcat (Ψwinter = 0.40 CI: 0.19–0.63; Ψautumn = 0.52 CI: 0.17–0.78)
  5. We found that marginal occupancy predictors for carnivores varied between seasons. We also found differences in predictors of co‐occurrence between seasons for both lynx‐wolf and wildcat‐wolf co‐occurrence. For both seasons, we found that conditional occupancy probabilities of all three species were higher when another species was present.
  6. Our results indicate that while there are seasonal differences in predictors of occupancy and co‐occurrence of the three species, co‐occurrence in our study area is high.
  7. Terrestrial carnivore recovery efforts are ongoing worldwide. Insights into interspecific relations between carnivore species are critical when considering the depauperate communities they are introduced in. Our work showcases that apex carnivore coexistence is possible, but dependent on protection afforded to forest habitats and their prey base.
  相似文献   

14.
  1. DNA metabarcoding is widely used to characterize the diet of species, and it becomes very relevant for biodiversity conservation, allowing the understanding of trophic chains and the impact of invasive species. The need for cost‐effective biodiversity monitoring methods fostered advances in this technique. One question that arises is which sample type provides a better diet representation.
  2. Therefore, with this study, we intended to evaluate if there were differences in diet estimates according to the section of the gastrointestinal tract analysed and which section(s) provided the best diet representation. Additionally, we intended to infer the ecological/economic impacts of an invader as a model of the potential effects in an originally mammal‐free ecosystem.
  3. We examined the gut contents of the house mouse Mus musculus introduced to Cabo Verde, considering three sections: stomach, small intestine, and large intestine. We applied a DNA‐metabarcoding approach using two genetic markers, one specific for plants and another for invertebrates.
  4. We showed that this invader consumed 131 taxa (73 plants and 58 invertebrates). We obtained significant differences in the composition of two of the three sections, with a higher incidence of invertebrates in the stomach and plants in the intestines. This may be due to stomach inhibitors acting on plants and/or to faster absorption of soft‐body invertebrates compared to the plant fibers in the intestines. We verified that the impact of this invader in the ecosystem is predominantly negative, as at least 50% of the ingested items were native, endemic, or economically important taxa, and only 19% of the diet items were exotics.
  5. Overall, results showed the need to analyse only two gastrointestinal tract sections to obtain robust diet data, increasing the cost‐effectiveness of the method. Furthermore, by uncovering the native taxa most frequently preyed on by mice, this DNA‐metabarcoding approach allowed us to evaluate efficiently which are at the highest risk.
  相似文献   

15.
Mammalian carnivores play an important role in regulating food webs and ecosystems. While many carnivore populations are facing various threats such as habitat loss and fragmentation, poaching, and illegal trade, others have adapted to human-dominated landscapes. Information about Neotropical carnivore communities in particular is limited, especially in disturbed landscapes. We conducted a camera trap survey at 38 sites across the San Juan–La Selva Biological Corridor in Costa Rica to assess occupancy and detection probabilities of the carnivore community. We developed hypotheses within a likelihood-based framework in order to determine the landscape features and species traits (diet and size) that influenced their occupancy. We detected nine of the 13 native carnivores predicted to occur in the corridor. When modeled separately, each species responded to land cover changes differently, suggesting no strong community-wide predictors of occupancy. We then modeled three separate guilds within the carnivore community: omnivorous mesopredators, obligate carnivorous mesopredators, and apex predators. These community guild models revealed a negative relationship between omnivorous mesopredators and increasing forest and tree plantation cover, suggesting omnivores utilize forest fragments and edge habitats in agricultural landscapes. Obligate carnivorous mesopredator models did not reveal any strong habitat relationships, but landscape effects tended to contradict our a priori predictions. Apex predators were positively associated with increasing forest and tree plantation cover, protected areas, and increasing distances to villages. Alarmingly, apex predators and obligate carnivorous mesopredators were generally rare within the biological corridor. A lack of top-down control alone might result in heightened occupancy for all mesopredators, but because the community is dominated by omnivorous species, bottom-up release from human-induced land cover changes and resource provision may better explain their high occupancy.  相似文献   

16.
Bees rely on floral pollen and nectar for food. Therefore, pollinator friendly plantings are often used to enrich habitats in bee conservation efforts. As part of these plantings, non‐native plants may provide valuable floral resources, but their effects on native bee communities have not been assessed in direct comparison with native pollinator friendly plantings. In this study, we performed a common garden experiment by seeding mixes of 20 native and 20 non‐native pollinator friendly plant species at separate neighboring plots at three sites in Maryland, USA, and recorded flower visitors for 2 years. A total of 3,744 bees (120 species) were collected. Bee abundance and species richness were either similar across plant types (midseason and for abundance also late season) or lower at native than at non‐native plots (early season and for richness also late season). The overall bee community composition differed significantly between native and non‐native plots, with 11 and 23 bee species being found exclusively at one plot type or the other, respectively. Additionally, some species were more abundant at native plant plots, while others were more abundant at non‐natives. Native plants hosted more specialized plant–bee visitation networks than non‐native plants. Three species out of the five most abundant bee species were more specialized when foraging on native plants than on non‐native plants. Overall, visitation networks were more specialized in the early season than in late seasons. Our findings suggest that non‐native plants can benefit native pollinators, but may alter foraging patterns, bee community assemblage, and bee–plant network structures.  相似文献   

17.
《农业工程》2022,42(6):679-683
Urban expansions into natural habitats have forced many carnivores to adapt to the modified areas; however, our understanding of their ecology in such areas is limited. The Indian fox (Vulpes bengalensis) is a small carnivore species that can adapt and exploit urban areas due to its generalist nature, but there is a paucity of data on Indian foxes in these human-modified areas. To understand the resource requirement of Indian foxes in urban habitats, we conducted a diet analysis by examining 119 scats of Indian foxes in a peri-urban habitat of Baripada town, Odisha, eastern India. To determine the diet composition of Indian foxes, we analyzed scat contents by their frequency occurrence (%FO), the relative frequency of occurrence (%RF) and mean percent volume (%Vm). Indian foxes consumed a wide range of food categories, including arthropods, rodents, reptiles, birds, plant parts and anthropogenic resources. In %Vm, rodents showed the highest volume, followed by polythene, Spondias pinnata fruit and Coleoptera. We found anthropogenic foods in considerable quantities, including polythene and paper. The diet of Indian foxes indicates that the species has opportunistic and generalist feeding habits consisting primarily of easily accessible foods. Furthermore, management efforts should focus on the proper management of waste and control of anthropogenic food sources in urban habitats.  相似文献   

18.
19.
  1. Large carnivores play critical roles in terrestrial ecosystems but have suffered dramatic range contractions over the past two centuries. Developing an accurate understanding of large carnivore diets is an important first step towards an improved understanding of their ecological roles and addressing the conservation challenges faced by these species.
  2. The puma is one of seven large felid species in the world and the only one native to the non‐tropical regions of the New World. We conducted a meta‐analysis of puma diets across the species’ range in the Americas and assessed the impact of varying environmental conditions, niche roles, and human activity on puma diets. Pumas displayed remarkable dietary flexibility, consuming at least 232 different prey species, including one Critically Endangered and five Endangered species.
  3. Our meta‐analysis found clear patterns in puma diets with changing habitat and environmental conditions. Pumas consumed more larger‐bodied prey species with increasing distance from the equator, but consumption of medium‐sized species showed the opposite trend.
  4. Puma diets varied with their realized niche; however, contrary to our expectations, puma consumption of large species did not change with their trophic position, and pumas consumed more small prey and birds as apex predators. Consumption of domestic species was negatively correlated with consumption of medium‐sized wild species, a finding which underscores the importance of maintaining intact native prey assemblages.
  5. The tremendous dietary flexibility displayed by pumas represents both an opportunity and a challenge for understanding the puma’s role in ecosystems and for the species’ management and conservation. Future studies should explore the linkages between availability and selection of primary and other wild prey, and consequent impacts on predation of domestic species, in order to guide conservation actions and reduce conflict between pumas and people.
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20.

Background

A plant is considered carnivorous if it receives any noticeable benefit from catching small animals. The morphological and physiological adaptations to carnivorous existence is most complex in plants, thanks to which carnivorous plants have been cited by Darwin as ‘the most wonderful plants in the world’. When considering the range of these adaptations, one realizes that the carnivory is a result of a multitude of different features.

Scope

This review discusses a selection of relevant articles, culled from a wide array of research topics on plant carnivory, and focuses in particular on physiological processes associated with active trapping and digestion of prey. Carnivory offers the plants special advantages in habitats where nutrient supply is scarce. Counterbalancing costs are the investments in synthesis and the maintenance of trapping organs and hydrolysing enzymes. With the progress in genetic, molecular and microscopic techniques, we are well on the way to a full appreciation of various aspects of plant carnivory.

Conclusions

Sufficiently complex to be of scientific interest and finite enough to allow conclusive appraisal, carnivorous plants can be viewed as unique models for the examination of rapid organ movements, plant excitability, enzyme secretion, nutrient absorption, food-web relationships, phylogenetic and intergeneric relationships or structural and mineral investment in carnivory.  相似文献   

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