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1.
We tested the widely accepted hypothesis that spotted hyaenas (Crocuta crocuta) are non-selective in their diet. The prey preference of spotted hyaena was studied in the Addo Elephant National Park (AENP),
South Africa. Diet (frequency of occurrence of prey items in the diet) was quantified through the analysis of 55 scats, and
compared with available prey. A combination of large- and medium-sized mammals (buffalo (Syncerus caffer), red hartebeest (Alcelaphus buselaphus) and common duiker (Sylvicapra grimmia) were the most preferred prey items. The most abundant species, warthog (Phacochoerus africanus) and kudu (Tragelaphus strepsiceros), were ignored and avoided, respectively. These results show that the assumption that hyaena prey on the most abundant available
prey species may be overly simplistic. Predation patterns, such as the ones observed in AENP, may have important ramifications
for less common species that are selected by hyaena in small enclosed reserves. 相似文献
2.
A. David M. Latham M. Cecilia Latham Kyle H. Knopff Mark Hebblewhite Stan Boutin 《Ecography》2013,36(12):1276-1290
Population increases of primary prey can negatively impact alternate prey populations via demographic and behavioural responses of a shared predator through apparent competition. Seasonal variation in prey selection patterns by predators also can affect secondary and incidental prey by reducing spatial separation. Global warming and landscape changes in Alberta's bitumen sands have resulted in prey enrichment, which is changing the large mammal predator–prey system and causing declines in woodland caribou Rangifer tarandus caribou populations. We assessed seasonal patterns of prey use and spatial selection by wolves Canis lupus in two woodland caribou ranges in northeastern Alberta, Canada, that have undergone prey enrichment following recent white‐tailed deer Odocoileus virginianus invasion. We determined whether risk of predation for caribou (incidental prey) and the proportion of wolf‐caused‐caribou mortalities varied with season. We found that wolves showed seasonal variation in primary prey use, with deer and beaver Castor canadensis being the most common prey items in wolf diet in winter and summer, respectively. These seasonal dietary patterns were reflected in seasonal wolf spatial resource selection and resulted in contrasting spatial relationships between wolves and caribou. During winter, wolf selection for areas used by deer maintained strong spatial separation between wolves and caribou, whereas wolf selection for areas used by beaver in summer increased the overlap with caribou. Changing patterns in wolf resource selection were reflected by caribou mortality patterns, with 76.2% of 42 adult female caribou mortalities occurring in summer. Understanding seasonal patterns of predation following prey enrichment in a multiprey system is essential when assessing the effect of predation on an incidental prey species. Our results support the conclusion that wolves are proximately responsible for woodland caribou population declines throughout much of their range. 相似文献
3.
Mattioli Luca Capitani Claudia Gazzola Andrea Scandura Massimo Apollonio Marco 《European Journal of Wildlife Research》2011,57(4):909-922
Studies on predation by the wolf (Canis lupus) have often reported contradictory results about the role of prey density and vulnerability on wolf prey use. We investigated
dietary response and prey selection by wolves in a high-density and multi-species ungulate community, analysing scats collected
over a period of 11 years in the Casentinesi Forests, Italy. The second most abundant species, wild boar (Sus scrofa), was found to be the main wolf prey, and we did not observe any dietary response of wolves to variations in the density
of either primary or secondary prey species. Selection patterns were uniform throughout the study period. Wolves strongly
selected for wild boar piglets, while roe deer (Capreolus capreolus) fawns and adults, red deer (Cervus elaphus) adults and fallow deer (Dama dama) adults were avoided. Wolf preference for wild boar was inversely density dependent. Within each species, juveniles were
preferred to adults. Medium-sized, young individuals of both wild boar and roe deer were optimal prey, although with different
selection patterns related to the different anti-predator strategies adopted by each prey species. The results of this study
suggest that in productive ecosystems with high density and high renewal rates of prey, selection patterns by wolves are determined
by prey vulnerability, which is connected to prey age and body size. The different patterns of wild boar versus cervids use
by wolf across Europe seems to be related to their relative abundances, while the strong selection of wild boar in Italian
Apennines with respect to the more frequent avoidance in central-eastern Europe is better explained by higher piglet productivity
and smaller body size of adults boar in Mediterranean temperate forests. 相似文献
4.
J. Santamarina 《Hydrobiologia》1993,252(2):175-191
The food resource use of a stream in NW Spain by fish (Salmo trutta L. and Anguilla anguilla L.), birds (Cinclus cinclus L. and Motacilla cinerea L.) and mammals (Galemys pyrenaicus G. and Neomys anomalus C.) was studied. Data on seasonal diets and stream benthos prey were used to determine prey selection patterns.Caddisfly larvae are the main resource for Cinclus and Galemys, but these predators also consumed other benthic prey. Salmo fed on a wide range of benthic invertebrates, emergent pupae and terrestrial prey, whereas Anguilla consumed primarily benthic invertebrates, especially Lumbricids. Neomys fed mainly on terrestrial prey (Gasteropods and Lumbricids), but also consumed aquatic prey. Motacilla captured aquatic insects both in larval and aerial stages, as well as terrestrial prey.Both prey availability and selection led to seasonal differences in the use of food resources. All species showed a marked prey selection of aquatic taxa. Prey size plays an important role in this selection, most species consuming the largest of available prey sizes. In spite of the fact that all species feed upon freshwater invertebrates, substantial resource partitioning was observed in all seasons. This partitioning may be attributable to morpholological and physiological differences. Nevertheless, Anguilla and Galemys, two quite different animals, did feed on the same prey much of the time. 相似文献
5.
CALUM MACNEIL † JAIMIE T. A. DICK ROBERT W. ELWOOD 《Biological reviews of the Cambridge Philosophical Society》1999,74(4):375-395
Gammarus spp. (Crustacea: Amphipoda) are widespread throughout a diverse range of marine, freshwater and estuarine/brackish habitats, often dominating benthic macroinvertebrate communities in terms of both numbers and/or biomass. Gammarus spp. are the dominant macroinvertebrate prey items of many fish, whether as a seasonal food source or a year-round staple. Selective predation by fish on Gammarus spp. is often linked to parasitism and the body size of the prey. Gammarus spp. populations are under increasing threat from both pollution and replacement/displacement by introduced species. Loss of populations and species invasions/replacements could have significant impacts on native predator species if the predator(s) cannot successfully adapt their feeding patterns to cope with non-indigenous Gammarus prey species. Despite this, many fish predation studies do not identify Gammarus prey to species level. This lack of precision could be important, as Gammarus spp. exhibit wide variations in physiochemical tolerances, habitat requirements, abilities to invade and susceptibility to replacement. Although rarely acknowledged, the impacts of nonpiscean predators (particularly macroinvertebrates) on Gammarus prey species may frequently be stronger than those exerted by fish. A major aim of this review is to ascertain the current importance of Gammarus as a prey species, such that the implications of changes in Gammarus spp. populations can be more accurately assessed by interested groups such as ecologists and fisheries managers. We also review the dynamics of Gammarus spp. as prey to a diverse array of mammals, birds, amphibians, insects, flatworms, other crustaceans such as crabs and crayfish and, perhaps most importantly, other Gammarus spp. 相似文献
6.
Russell A. McWilliam Todd E. Minchinton David J. Ayre 《Biological journal of the Linnean Society. Linnean Society of London》2013,108(4):812-820
The diets of predators should reflect interactions between their behavioural and anatomical constraints and the availability and accessibility of prey, although feeding preferences may also reflect adaptation to locally abundant prey, particularly in closed populations. On the south‐east coast of Australia, the whelk Haustrum vinosum (Lamarck, 1822) and its prey communities provide a model system in which to test the effect of variation in prey availability on diet and dietary preferences. Haustrum vinosum is a direct developing species, forming effectively closed populations, with the potential for local adaptation at local and regional scales. Here we show that populations of whelks east and west of a biogeographical barrier encounter different prey assemblages, and have different feeding patterns and apparent prey preferences. We then use a prey choice experiment to test for evidence that H. vinosum from three populations west of the barrier display an inherent preference for its most frequently encountered western prey species, the mussel Brachidontes rostratus (Dunker, 1857), over a novel prey, the barnacle Tesseropora rosea (Krauss, 1848). We detected no prey preference within any population, suggesting past association with B. rostratus did not influence prey selection. Our data support the hypothesis that predators with limited dispersal and high population differentiation are able to maintain flexible generalist foraging patterns, even when they encounter novel prey. © 2013 The Linnean Society of London 相似文献
7.
L. J. Vitt S. S. Sartorius T. C. S. Avila-Pires M. C. Espósito D. B. Miles 《Oecologia》2000,122(3):410-420
We examined standard niche axes (time, place, and food) for three sympatric teiid lizards in the Amazon rain forest. Activity
times during the day were similar among species. Ameiva ameiva were in more open microhabitats and had higher body temperatures compared with the two species of Kentropyx. Microhabitat overlaps were low and not significantly different from simulations based on Monte Carlo analysis. Grasshoppers,
crickets, and spiders were important in the diets of all three species and many relatively abundant prey were infrequently
eaten (e.g., ants). Dietary overlaps were most similar between the two species of Kentropyx even though microhabitat overlaps were relatively low. A Monte Carlo analysis on prey types revealed that dietary overlaps
were higher at all ranks than simulated overlaps indicating that use of prey is not random. Although prey size was correlated
with lizard body size, there were no species differences in adjusted prey size. A. ameiva ate more prey items at a given body size than either species of Kentropyx. Body size varies among species, with A. ameiva being the largest and K. altamazonica the smallest. The two species of Kentropyx are most distant morphologically, with A. ameiva intermediate. The most distant species morphologically are the most similar in terms of prey types. A morphological analysis
including 15 species from four genera revealed patterns of covariation that reflected phylogenetic affinities (i.e., taxonomic
patterns are evident). A cluster analysis revealed that A. ameiva, K. pelviceps, and K. altamazonica were in the same morphological group and that within that group, A. ameiva differed from the rest of the species. In addition, K. pelviceps and K. altamazonica were distinguishable from other species of Kentropyx based on morphology.
Received: 26 December 1998 / Accepted: 15 September 1999 相似文献
8.
Kenneth M. Brown 《Oecologia》1981,50(3):380-385
Summary Foraging patterns were determined for three orbweaving spiders in several geographical locations varying in percent cover by herbaceous vegetation. Argiope trifasciata was the most common species in early successional habitats, while both Argiope aurantia and Araneus trifolium were more common in wetter, more herbaceous sites. Discriminant analysis revealed that web height selected for webs and body size were the variables that explained most of the variation among populations in foraging patterns. Argiope aurantia forages lowest in vegetation, A. trifasciata at intermediate heights, and A. trifolium near the top of the vegetation. The body size sequence is reversed.Web radius, spider size, and web height appear to explain much of the variation in abundance and size of prey in webs. Species foraging higher in the vegetation take more winged prey, while larger species foraging lower in the vegetation tend to take larger, jumping prey like acridids. Comparison of prey in webs with field estimates of potential prey suggests that orbweavers select large insect prey. Inferential evidence indicates that interspecific competition may be responsible for the divergence in foraging patterns among species reported here. However, field manipulative experiments have not yet indicated that competition among orb-weavers is severe. 相似文献
9.
M. S. Mahjoub G. Dur S. Souissi F.G. Schmitt J.S. Hwang 《Journal of fish biology》2016,88(5):1835-1846
It was hypothesized that the Malabar grouper Ephinephelus malabaricus larvae have developed search patterns adapted to the distribution of their prey to maximise their net energy intake per unit time. Analysis of the swimming behaviour of E. malabaricus larvae in both the presence and absence of Artemia sp. nauplii is presented to test this hypothesis. A method derived from turbulence studies (the moment function of the displacements) was used to characterize the behaviour. The results revealed that larval swimming pattern was multifractal (intermittent and long‐range‐correlated) and isotropic (i.e. uniform in all directions) in the presence of prey, but multifractal and anisotropic (i.e. more frequent long displacement on the vertical axis) in the absence of prey. It is suggested that the search behaviour observed in the absence of prey is an adaptive response to prey distribution pattern, which is often characterised by multifractality and anisotropy (i.e. larger patches on the horizontal axes). In the presence of prey, E. malabaricus shifted to intensive search behaviour. Other possible contributors to the observed patterns are discussed. It is concluded that multifractality and anisotropy of swimming patterns observed in the experiment are mainly explained in an optimal foraging theory framework. 相似文献
10.
The swimming and feeding behavior of Mesocyclops 总被引:1,自引:1,他引:0
Craig E. Williamson 《Hydrobiologia》1986,134(1):11-19
The swimming and feeding behaviors of Mesocyclops are described from a review of the literature and personal observations.
Mesocyclops exhibits considerable behavioral flexibility in response to environmental stimuli. Mesocyclops edax exhibits an increase in horizontal looping behavior at high prey densities, and performs a tight vertical looping behavior in response to the loss of captured prey. Ingestion rates by Mesocyclops are a complex function of prey density, morphology, and behavior in addition to prey size. Vertebrate predators induce a rapid escape response in Mesocyclops and may be responsible at least in part for their extensive diel vertical migrations. The complex behavioral patterns of Mesocyclops suggest that its distribution and abundance in nature will be distinctly nonrandom and influenced as much by its own behavioral responses as by other external physical factors such as water circulation patterns. 相似文献
11.
Sergio M. Pellis Renata C. E. Officer 《Ethology : formerly Zeitschrift fur Tierpsychologie》1987,75(3):177-196
Two aspects of predatory behaviour in five species of carnivorous mammals were studied: four species (Dasyurus viverrinus, Dasyurus hallucatus, Dasyuroides byrnei and Phascogale tapoatafa) of a group of Australian marsupials, Dasyuridae, and an eutherian, the domestic cat, Felis catus. All data were collected from captive animals in laboratory conditions. Using sequences of predatory behaviour recorded on movie film, two aspects of predation were compared: (a) attack strategy, that is, the behavioural patterns leading up to biting the prey, and (2) head shaking movements used during killing. All individual predators of all species but Dasyuroides byrnei exhibited avoidance of attacking prey from the front. Indeed, two of the four individual Dasyuroides used not only did not avoid frontal attack but selected to do so even when attacks from the rear or side were possible (e.g., the prey sat unmoving in the centre of the enclosure). Frontal attacks by Dasyuroides involved the use of the forepaws to grasp and pin prey, and the directing of killing bites to the head. These two behaviour patterns are also present in the other three species of dasyurids. Therefore, the frontal attack employed by this species does not involve the use of novel behaviour patterns. Analysis of head shakes revealed two basic forms. From a downward pointing position the head was rotated in one of two ways: the snout traversed an arc in space, as seen in Felis catus and Dasyurus hallucatus, or the sagittal crest traversed an arc in space, as seen in the other three species of dasyurids. When the prey is held down by the forepaws, either form of head shake enhances penetration of the canines into the prey, whereas, when not held down by the forepaws, both forms of head shake can disorient prey, enabling subsequent killing bites to be applied. 相似文献
12.
Feeding electivity was investigated in a non-outbreaking population of the crown-of-thorns starfish Acanthaster planci (L.) from North Sulawesi, Indonesia. A null model-based approach was used to assess the feeding pattern of Acanthaster in relation to the availability of coral prey in the field. Of a total of 70 species of corals recorded as prey, massive
species, particularly of Faviidae, tended to be more frequently consumed than would be expected under the assumption of random
feeding by A. planci. Branched and encrusting/laminar forms of corals that occurred in relatively exposed sites were apparently not preferred,
pointing to the importance of non-acroporan massive species of corals in cryptic habitats as prey for A. planci. The null model-based electivity index Z introduced here directly measured the deviation from random feeding, while two common indices (Ivlev’s and Vanderploeg and
Scavia’s) only partially reflected such deviations (hence, prey selection cannot be accurately demonstrated by these). Electivity
values (Z) for poritid species and Acropora palifera, the most common Acropora species in the study site, were significantly negative, indicating apparent avoidance of them by Acanthaster. Our results indicate that accessibility to different coral species and the choice/avoidance of certain species are the important
elements of feeding in non-outbreaking populations of Acanthaster inhabiting spatially variable reef environments. A similar consideration may apply to the feeding patterns of other corallivores
that possess superior/inferior mobility to Acanthaster. The present study emphasizes the merit of testing the observed patterns, using null models for a rigorous assessment of
feeding preferences. 相似文献
13.
Portia fimbriata from Queensland, a previously studied jumping spider (Salticidae), routinely includes web-building spiders and cursorial salticids in its diet, both of these types of prey being dangerous and unusual prey for a salticid. The present paper is the first detailed study ofP. fimbriata's prey preferences. Three basic types of tests of prey preference were used, providing evidence that (1)P. fimbriata males and females prefer spiders (both web-building spiders in webs and salticids away from webs) to insects; (2)P. fimbriata males and females prefer salticids to web-building spiders; (3)P. fimbriata males and females prefer larger spiders to smaller spiders; (4) there are intersexual differences in the preferences ofP. fimbriata for prey size, females preferring larger prey and males preferring smaller prey; and (5)P. fimbriata's prey preferences are not affected by a prior period without food of 2 weeks. When preferences were tested for by using both living, active prey and dead, motionless lures, the same preferences were expressed, indicating thatP. fimbriata can distinguish among different types of prey independent of the different movement patterns of different prey. 相似文献
14.
Ovarian dynamics and oosorption in two species of predatory lady beetles (Coleoptera: Coccinellidae)
Abstract Ovarian development and oviposition dynamics of two species of lady beetle, Coccinella septempunctata L. and C. transversoguttata richardsoni Brown, are examined in laboratory experiments in which pea aphids (Acyrthosiphon pisum Harris) are provided ad libitum and then removed. Both species respond to prey removal by stabilizing at lower body weights, and by laying progressively fewer and smaller eggs of reduced viability, until oviposition ceases altogether after several days of starvation. Dissections of females after prey removal reveal similar patterns of oosorption in both species. However, C. septempunctata reduces oviposition more rapidly after prey removal than does C. transversoguttata. When prey are again provided, C. septempunctata soon lay as many eggs as previously but C. transversoguttata lay fewer. Females, especially of C. septempunctata, that stop producing and resorb eggs in the absence of prey lay more eggs subsequently than do females that feed continually on prey provided ad libitum and lay eggs throughout the experiment. Thus, although both species are responsive to a rapid change in prey availability, C. septempunctata appears to be especially responsive. Rapid responses to changes in prey availability may contribute to the greater abundance and reproductive success of this introduced species relative to the native C. transversoguttata in western North American alfalfa fields that exhibit widely varying pea aphid densities. However, both species engage in oosorption as a means of reserving resources under poor prey conditions and enhancing future reproductive effort when prey conditions improve. 相似文献
15.
Aim The endoparasites of Sebastes capensis Gmelin are examined over most of its geographical range (coasts of Peru, Chile, Argentina and South Africa) to determine: (1) whether the endoparasite communities of this fish show zoogeographical patterns; and (2) if so, whether there are any relationships between spatial variations in the endoparasite fauna and known zoogeographical patterns for marine free‐living organisms (e.g. prey that are included in the life cycles of endoparasites). Location Fish were captured at nine localities along the Pacific coast of South America, from 11° S in the centre of the Peruvian coast, to 52° S in southern Chile, and also at two localities in the Atlantic Ocean, at 43° S in Argentina, and 34° S in South Africa. Methods From April to September 2003 and April to August 2004, 626 fish were captured. Endoparasites and diet were examined following traditional methods. Cluster analyses were used to evaluate the distribution patterns of the endoparasite communities, and to evaluate similarities in the prey composition per locality. Results The endoparasite fauna of S. capensis consisted of four species widely distributed along the Pacific coast: Ascarophis cf. sebastodis, Anisakis sp., Corynosoma australe, and Pseudopecoelus sp. Other parasites were distributed only in some geographical areas. The species richness of the parasite communities increased with latitude along the Pacific coast, while parasite communities from Argentina and South Africa showed low species richness. Cluster analyses based on endoparasite composition and on prey composition grouped localities in a way consistent with known biogeographical areas for marine free‐living organisms. Main conclusions The endoparasites of S. capensis exhibit a pattern associated with known biogeographical areas for free‐living organisms. The latitudinal increase in endoparasite community richness is associated with changes in prey composition (intermediate hosts) and also possibly with the presence of definitive hosts. Therefore, the biogeographical patterns of prey are considered key determinants of the endoparasite community structure of the host. 相似文献
16.
Fish predation on Notonecta (Hemiptera): relationship between prey risk and habitat utilization 总被引:4,自引:0,他引:4
Summary Prey risk was examined in the laboratory to compare the ability of 6 Notonecta species to coexist with insectivorous fishes (Lepomis cyanellus, L. gibbosus). Because of their smaller size, lighter color, greater tendency to remain motionless in the presence of the predator, greater ability to avoid capture when attacked, and predicted lower profitability as prey, N. lunata and N. petrunkevitchi were estimated to have the lowest prey risk and greatest chance of coexisting with insectivorous fishes in nature. The 2 largest notonectids, N. irrorata and N. insulata, both highly melanistic and rapidly discovered by foraging sunfishes, were judged to be the most susceptible to predation by large fishes. The presence of vegetation as a potential refuge tended to decrease prey risk but did not significantly alter the relative risk among the prey species. Finally, the relative prey risk measured in the laboratory was consistent with the general distribution of these species in relation to fishes in local habitats. We suggest that fish predation is an important determinant of Notonecta habitat utilization patterns. 相似文献
17.
Abstract The foraging behaviour, web characteristics and prey availability of two sympatric orb-weaving spiders, Nephila plumipes and Eriophora transmarina (Araneae: Araneoidea), are compared. The spiders are similarly sized but have different temporal foraging patterns. Nephila plumipes spins a relatively permanent web and captures most of its prey during the day. Eriophora transmarina only forages at night, spinning a new web every night and usually dismantling it at dawn. These different foraging activities are most likely to be responsible for the observed differences in the types and rates of prey capture: E. transmarina captured mostly Lepidoptera that were more abundant at night than during the day, while N. plumipes captured mostly Hymenoptera that were more abundant during the day than at night. While nocturnal E. transmarina have less time available for foraging than the diurnal N. plumipes, the former has a substantially higher nocturnal prey capture rate. We argue that the difference between the species in their prey capture rates are likely to be due to differences in the architecture of their webs. 相似文献
18.
Spatial variation in the density and vulnerability of preferred prey in the landscape shape patterns of Amur tiger habitat use
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Yuri K. Petrunenko Robert A. Montgomery Ivan V. Seryodkin Olga Y. Zaumyslova Dale G. Miquelle David W. Macdonald 《Oikos》2016,125(1):66-75
Theoretical and empirical research suggests that carnivore distributions are largely determined by prey availability. Availability depends not only on prey density but also on prey accessibility which is affected, in part, by the configuration of landscape attributes that make prey vulnerable to predation. Exactly how spatial variation in these processes shape patterns of carnivore habitat use at the home range scale remains poorly understood. We examined the influence of prey density (negative binomial resource selection function) and vulnerability (kill site resource selection function), mapped separately for each of three species of primary prey, on habitat use patterns within the home range for Amur tigers Panthera tigris altaica in Far East Russia over 20 winters. We developed spatially‐explicit mixed linear regression models to assess these patterns and found that models with parameters for specific primary prey were more robust than models with composite parameters for all primary prey species. This emphasizes the importance of evaluating predation dynamics at a species‐specific level. We also found that Amur tigers used habitat within the home range where red deer Cervus elaphus and wild boar Sus scrofa were dense. These two species were clearly preferred by tigers accounting for 72% (201 of the 278) of the tiger kills detected. The effect of red deer density however, was modulated by the vulnerability of red deer in the landscape. Amur tigers tended to establish their home ranges on habitat where red deer were most vulnerable to predation, but would use habitat where red deer were dense in the peripheral regions of their home ranges. This suggests that tigers may utilize two separate strategies for acquiring prey. As the configuration of resource patches within the home range influences carnivore survival and reproduction, our analysis has implications for tiger conservation that extend beyond our improved understanding of tiger‐prey ecology. 相似文献
19.
Natalie V. Klinard Jordan K. Matley Silviya V. Ivanova Sarah M. Larocque Aaron T. Fisk Timothy B. Johnson 《Journal of fish biology》2021,98(1):237-250
Understanding predator–prey interactions and food web dynamics is important for ecosystem-based management in aquatic environments, as they experience increasing rates of human-induced changes, such as the addition and removal of fishes. To quantify the post-stocking survival and predation of a prey fish in Lake Ontario, 48 bloater Coregonus hoyi were tagged with acoustic telemetry predation tags and were tracked on an array of 105 acoustic receivers from November 2018 to June 2019. Putative predators of tagged bloater were identified by comparing movement patterns of six species of salmonids (i.e., predators) in Lake Ontario with the post-predated movements of bloater (i.e., prey) using a random forests algorithm, a type of supervised machine learning. A total of 25 bloater (53% of all detected) were consumed by predators on average (± S.D. ) 3.1 ± 2.1 days after release. Post-predation detections of predators occurred for an average (± S.D. ) of 78.9 ± 76.9 days, providing sufficient detection data to classify movement patterns. Tagged lake trout Salvelinus namaycush provided the most reliable classification from behavioural predictor variables (89% success rate) and was identified as the main consumer of bloater (consumed 50%). Movement networks between predicted and tagged lake trout were significantly correlated over a 6 month period, supporting the classification of lake trout as a common bloater predator. This study demonstrated the ability of supervised learning techniques to provide greater insight into the fate of stocked fishes and predator–prey dynamics, and this technique is widely applicable to inform future stocking and other management efforts. 相似文献
20.
Corallivorous gastropods of the genus Drupella are known for population outbreaks throughout the Indo-Pacific region. Despite their potential to destroy wide areas of coral
reef, prey preferences have never been analyzed with respect to prey availability, and juvenile ecology and food selectivity
remain largely unknown. Here, the influence of water depth, coral abundance, colony shape, prey species, and intraspecific
attraction among snails on distribution patterns, prey selection, and microhabitat use of D. cornus was studied in the northern Red Sea. Special emphasis was put on ontogenetic differences. The snails were most abundant in
the shallowest reef zone (1 m depth). Adults were associated with several substrates and coral growth forms, whereas juveniles
were highly cryptic and restricted to live branching corals. The genus Acropora was significantly preferred over other acroporid and pocilloporid corals. As revealed by resource selection ratios, Acropora acuminata was preferred by juveniles, A. selago by adults. In aquarium experiments, intraspecific attraction was high among both life stages. Overall, significant differences
in juvenile and adult microhabitat and prey use suggest that juveniles have more specific habitat requirements, and indicate
ecological impacts on coral communities different from that of adults. Prey preferences seem to depend on both coral genus
and colony shape. Acropora corals provide the best combination of food and shelter and therefore determine distribution patterns of D. cornus. 相似文献