Academic literature on the topic 'Macropod behaviour'

This paper introduces a series of papers on the ecology, social organisation and behaviour of populations of sympatric macropods (Macropodoidea : Marsupialia) in north-eastern New South Wales. The study site, in the valley of Wallaby Creek, covers partly tree-cleared cattle-grazed pastures and also wet and dry forest communities; 10 species of macropods live there. The valley has a moderately high rainfall (1023 mm per annum), falling predominately in summer, and an equable climate of cool winters and warm summers. Soils derived from sedimentary and basaltic rocks and alluvium support naturally diverse plant associations further diversified by clearing and establishment of pasture and weed species. Macropods favouring open country occupy the pastures, which can also be used by cover-dependent species where pasture abuts forest or remnant patches of cover. Composition of the macropod community has changed since development of the pasture zone. Dingoes, major predators of some of the macropods, are abundant, and all exotic mammals other than cattle are rare. Populations of two of the macropod species are habituated to approach by observers, and close observation, on foot, of undisturbed animals has become our common study technique. A 1-ha grid has been established over 3.7 km2 of the study site to facilitate exact location of animals and observations. The suitability of the macropod populations for this kind of study results from the attitudes of the landholders.

Artificial food patches were used to examine whether red bellied-pademelons (Thylogale billiardierii) and Bennett’s wallabies (Macropus rufogriseus rufogriseus) altered their foraging behaviour in an open habitat (a young plantation) in response to distance from cover, used as a surrogate for predation risk. Analyses using the full dataset showed no significant relationship between the amount of food eaten at a station and any of the cover variables. In contrast, regression analyses of the upper bounds dataset indicated that both increased distance from windrow (2.5-m-high stacks of burnt wood) and from nearest cover (windrow or forest at plantation edge) significantly reduced the amount of food consumed at a station. This indicates that distance from cover acts as a constraint on the amount of food eaten. When the feeding-station data were overlayed onto a map of scat densities across the study site, the amount of food eaten was positively related to the density of scats of both red-bellied pademelons and Bennett’s wallabies. Our results demonstrate that these macropods trade-off increased foraging benefits in order to forage closer to protective cover. Furthermore, they represent the first time that artificial food patches, with progressively decreasing reward per search effort, have been used to assess foraging behaviour in macropods. This opens up a wide range of research opportunities aimed at examining macropod foraging, with both ecological and practical applications.

Context Feral cats threaten wildlife conservation through a range of direct and indirect effects. However, most studies that have evaluated the impacts of feral cats on species of conservation significance have focussed on direct impacts such as predation; few studies have considered the indirect impacts of cat-borne disease. Toxoplasma gondii, a cat-borne parasite, causes both acute and latent disease in a range of wildlife species, and macropods are particularly susceptible. Kangaroo Island is Australia’s third largest island and supports a high density of feral cats and high seroprevalence of T. gondii in multiple species, relative to the mainland. This suggests that Kangaroo Island has a high environmental contamination with the parasite and a high risk of infection for other species. Aims We aimed to describe T. gondii seroprevalence in culled and road-killed macropods, so as to assess the effects of island versus mainland location, sex, species and behaviour. Methods Macropod sera were tested for T. gondii IgG antibodies using a commercially available modified agglutination test. Key results The seroprevalence of T. gondii in culled western grey kangaroos (Macropus fuliginosus) was significantly higher on the island (20%, 11/54 positive) than on the mainland (0%, 0/61 positive). There was no difference in T. gondii seroprevalence between culled and road-killed (21%, 21/102 positive) kangaroos from the island. The seroprevalence of T. gondii was significantly higher in female (32%, 12/38 positive) than in male (13%, 8/60 positive) kangaroos, but we observed no sex effect in tammar wallabies (Macropus eugenii), and no effect of species. Conclusions The higher T. gondii seroprevalence in insular macropods supports previous reports of higher T. gondii exposure in other Kangaroo Island fauna. The lack of difference in T. gondii seroprevalence between culled and road-killed kangaroos suggests that T. gondii-positive animals are not more vulnerable to road mortality, in contrast to that suggested previously. Implications Our findings suggest greater potential adverse conservation impacts owing to toxoplasmosis on the island than on the mainland. In light of a recent study demonstrating higher cat abundance on the island than on the mainland, the higher observed T. gondii seroprevalence in insular macropods is likely to be a consequence of higher cat density.

Context When measuring grazing impacts of vertebrates, the density of animals and time spent foraging are important. Traditionally, dung pellet counts are used to index macropod grazing density, and a direct relationship between herbivore density and foraging impact is assumed. However, rarely are pellet deposition rates measured or compared with camera-trap indices. Aims The aims were to pilot an efficient and reliable camera-trapping method for monitoring macropod grazing density and activity patterns, and to contrast pellet counts with macropod counts from camera trapping, for estimating macropod grazing density. Methods Camera traps were deployed on stratified plots in a fenced enclosure containing a captive macropod population and the experiment was repeated in the same season in the following year after population reduction. Camera-based macropod counts were compared with pellet counts and pellet deposition rates were estimated using both datasets. Macropod frequency was estimated, activity patterns developed, and the variability between resting and grazing plots and the two estimates of macropod density was investigated. Key Results Camera-trap grazing density indices initially correlated well with pellet count indices (r2=0.86), but were less reliable between years. Site stratification enabled a significant relationship to be identified between camera-trap counts and pellet counts in grazing plots. Camera-trap indices were consistent for estimating grazing density in both surveys but were not useful for estimating absolute abundance in this study. Conclusions Camera trapping was efficient and reliable for estimating macropod activity patterns. Although significant, the relationship between pellet count indices and macropod grazing density based on camera-trapping indices was not strong; this was due to variability in macropod pellet deposition rates over different years. Time-lapse camera imagery has potential for simultaneously assessing herbivore foraging activity budgets with grazing densities and vegetation change. Further work is required to refine the use of camera-trapping indices for estimation of absolute abundance. Implications Time-lapse camera trapping and site-stratified sampling allow concurrent assessment of grazing density and grazing behaviour at plot and landscape scale.

I determined the sex of a total of 251 road-kills of six macropod species in southern Australia over a 13-year period. There was a significant bias towards males in five species, ranging from 65 to 92% males, but there was no difference from parity in the red kangaroo, Macropus rufus. Male eastern grey kangaroos, M. giganteus, and male western grey kangaroos, M. fuliginosus, probably behave in ways that expose them to vehicles more than females. Male-biased road-kills of swamp wallabies, Wallabia bicolor, may reflect skewed population sex ratios. There are insufficient data on the behaviour and population structure of the red-necked wallaby, M. rufogriseus, and rufous-bellied pademelon, Thylogale billardierii, to determine which explanation is responsible for male-biased road mortality in these species.

While preparing a review of published descriptions of copulatory behaviour in macropod marsupials (McLean, Lundie-Smith and Jarman 1993), we were surprised to find no description for one of the most studied species, the quokka (Setonix brachyurus, e.g. see Bradshaw 1983). Copulating quokkas have been seen previously by researchers (e.g. Kitchener 1970), but no account was given. Here we provide descriptions of copulatory behaviour in quokkas, and comment on levels of sexual behaviour and activity by quokkas in the wild and in captivity.

Translocated captive-bred predators are less skilled at hunting than wild-born predators and more prone to starvation post-release. Foraging in an unfamiliar environment presents many further risks to translocated animals. Knowledge of the diet and foraging behaviour of translocated animals is therefore an important consideration of reintroductions. We investigated the diet of the endangered meso-predator, the eastern quoll Dasyurus viverrinus. We also opportunistically observed foraging behaviour, enabling us to examine risks associated with foraging. Sixty captive-bred eastern quolls were reintroduced to an unfenced reserve on mainland Australia (where introduced predators are managed) over a two year period (2018, 2019). Quolls were supplementary fed macropod meat but were also able to forage freely. Dietary analysis of scats (n = 56) revealed that quolls ate macropods, small mammals, birds, invertebrates, fish, reptiles and frogs, with some between-year differences in the frequency of different diet categories. We also observed quolls hunting live prey. Quolls utilised supplementary feeding stations, indicating that this may be an important strategy during the establishment phase. Our study demonstrated that, in a novel environment, captive-bred quolls were able to locate food and hunt live prey. However, foraging was not without risks; with the ingestion of toxic substances and foraging in dangerous environments found to be potentially harmful. Knowledge of the diet of reintroduced fauna in natural landscapes is important for understanding foraging behaviour and evaluating habitat suitability for future translocations and management.

A comparative study of macroscopic and microscopic dimensions of the intestines in five macropod species indicated that the grazing macropods (the red kangaroo, Macropus rufus, and the eastern grey kangaroo, Macropus giganteus) had significantly longer caeca and large intestines than those of the browsing macropods (the swamp wallaby, Wallabia bicolor, and the red-necked pademelon, Thylogale thetis). This trend was not observed in the small intestine. The arid-adapted M. rufus also had a significantly longer large intestine than M. giganteus, which may be a water-conservation feature. Intestinal villi were tall in T. thetis, which consumed a less fibrous diet, whereas the agile wallaby, Macropus agilis, on a highly fibrous diet, had short villi; other macropods, on diets of medium fibre content, had villi of intermediate height. Thus, the size of the hindgut (i.e. caecum and large intestine) may provide an index of the specific feeding habit of a species (browsing or grazing), whilst parameters of the villi of the small intestine may reflect the quality of the animals' current diet.

Camera traps provide a novel and quasicovert method of gathering information on animal behaviour that may otherwise remain undetected without sophisticated and expensive filming equipment. In a rangelands pest management project at Mt Hope in the central west of New South Wales, Australia, we recorded foxes seemingly hunting kangaroos on three occasions. While we did not record direct instances of predation, our observations provide camera trap photographic evidence suggesting that foxes will attempt to tackle mammals above the critical weight range, including large macropod species such as western grey kangaroos.

In this study 10 free-roaming domestic dogs from an Aboriginal community were radio-collared to determine the sizes of their home ranges and to observe their wandering behaviour. Half of the radio-tagged dogs went on wandering forays, while the other five roamed only within the vicinity of the community. Home-range size was highly variable within the study group: the mean for the wandering dogs was 927 ha whereas that of the sedentary dogs was 2.6 ha. Dogs travelled 8–30 km on forays. All forays were initiated at night and those that were recorded had an average duration of 26 h. Foray destinations were usually riparian habitats where macropod quarry were abundant.

Colloidal macroions are known to interact very strongly with oppositely charged polyionic hydrogels. Sometimes this results in a non-uniform distribution of the macroions within the gel, a phenomenon that is not fully understood. This thesis is a summary of four papers on the development of a theory of the thermodynamics of macroions interacting with hydrogels, aimed at explaining the phenomenon of core/shell separation in spherical gels. It is the first theory of such interactions to use a rigorous approach to whole-gel mechanics, in which the elastic interplay between different parts of the gel is treated explicitly. The thesis shows that conventional theories of elasticity, earlier used on gels in pure solvent, can be generalised to apply also to gels in complex fluids, and that the general features of the phase behaviour are the same if mapped to corresponding system variables. It is found that the emergence of shells is due to attractions between macroions in the gel, mediated by polyions. Since the shell state is unfavourable from the perspective of the shell itself, being deformed from its preferred state, there will be a hysteresis between the uptake and the release of the macroion, like already known to occur with the uptake and release of pure solvent. Due to the elastic interplay, growth of the shell makes further growth progressively more favourable. Thus, unless there is a limited amount of macroions available the system will not reach equilibrium until complete phase transition has taken place. If the amount is limited the core/shell separation can be in equilibrium, so the volume of the solution that the gel is in contact with plays a very important part in determining the thermodynamic resting point of the system. The ability of a macroion/hydrogel to phase separate thus depends on the molecular properties whereas the ultimate fate of such a separation depends on the proportions in number between the ingoing components.

Résumé : La reproduction entraîne des dépenses énergétiques importantes chez les femelles mammifères. Ces dépenses sont supposées diminuer l'énergie disponible pour d'autres traits positivement corrélés à l'aptitude phénotypique et augmenter les besoins d'alimentation. Toutefois, des différences individuelles dans la capacité d'acquisition et d'allocation peuvent masquer l'impact négatif de l'effort reproducteur. La manipulation expérimentale de l'effort reproducteur et le contrôle statistique des effets individuels sont deux approches puissantes et complémentaires mises en œuvre dans le cadre de mon étude afin de contrôler pour l'hétérogénéité individuelle. Elles ont permis de montrer clairement un coût de la reproduction chez le kangourou gris de l'Est (Macropus giganteus). Dans un premier temps, nous avons trouvé que le coût de la reproduction affectait le montant d'énergie alloué à certaines fonctions somatiques (CHAPITRE I). L'effort reproducteur diminuait le gain de masse et la croissance des jambes pour des intervalles de capture supérieurs à deux ans. Chez les femelles non manipulées, un effet négatif sur le gain de masse était aussi observable pour un intervalle inférieur à 3 ans. À l'échelle de deux événements successifs de reproduction, le gain de masse et dans une moindre mesure la croissance des bras, mais non des jambes diminuaient avec un effort reproducteur plus important à la précédente reproduction. Ensuite, nous avons démontré qu'il y avait un coût de la reproduction en terme de futur succès reproducteur (CHAPITRE II). Les individus dont l'effort reproducteur avait été diminué expérimentalement produisaient davantage de jeunes qui survivaient au stade 'LPY', âgés approximativement de 7 mois, que les femelles contrôles. Ils diminuaient également davantage leur taux de reproduction en allongeant l'intervalle entre les naissances, mais la survie au sevrage n'était pas affectée. Le CHAPITRE III montre que les femelles adaptaient leur comportement alimentaire en fonction de leur statut reproducteur. En comparaison avec les individus manipulés ou ayant perdu leur jeune, les femelles allaitantes augmentaient leur temps passé à s'alimenter durant la journée, l'intensité de leurs bouchées et de leur mastication sans impliquer de compromis avec la vigilance. Nous avons aussi découvert que la survie au sevrage du jeune précédent menait à une augmentation du taux de bouchées pour l'année en cours. Les CHAPITRES I et II ont mis en évidence l'effet non négligeable des différences individuelles sur la détection des coûts de la reproduction. En effet, en l'absence de manipulation expérimentale ou de contrôle statistique, aucun compromis n'était détecté autant en terme de croissance que de prochaine reproduction. Au contraire, des corrélations positives entre l'effort reproducteur et les autres traits ont été trouvées. Le CHAPITRE I suggérait notamment que cette variabilité du succès reproducteur était liée à l'hétérogénéité individuelle dans le gain de masse maternelle qui augmentait la survie du jeune. Dans le CHAPITRE II, une corrélation positive entre les probabilités d'avoir un 'LPY' lors de deux événements successifs de reproduction suggérait que certaines femelles étaient capables de mener à bien ou non leur reproduction, mais cela indépendamment de l'effort reproducteur précédent. Enfin dans le dernier CHAPITRE (III), l'effet aléatoire était significatif dans l'analyse de différents comportements d'alimentation, ce qui pourrait être lié aux différences de gain de masse des femelles présentées dans le CHAPITRE I. Certaines contraintes individuelles affectant le coût de la reproduction ont été identifiées. La masse et la condition corporelle augmentaient le succès reproducteur et diminuaient l'intervalle entre deux naissances successives (CHAPITRES I et II), mais contrairement à de précédentes études le comportement d'alimentation des femelles n'était pas affecté par leur masse (CHAPITRE III). L'âge des individus avait également une influence. Les jeunes femelles croissaient davantage, avaient aussi une prise alimentaire plus importante et subissaient un coût de reproduction supérieur. Ce dernier se traduisait par un taux d'échec plus élevé à la reproduction suivante si les jeunes femelles avaient eu un jeune l'année précédente (CHAPITRES I, II et III). Des contraintes environnementales fortes influençaient la reproduction des femelles. La croissance, le succès reproducteur, l'intervalle entre les naissances et les comportements d'alimentation variaient suivant le site et l'année d'étude. Le site du Promontory et l'année 2011 apparaissaient particulièrement limitants. En effet en 2011, le gain de masse et le succès reproducteur ont diminué et l'intervalle de naissance et la prise de nourriture pour les femelles allaitantes ont augmenté (CHAPITRE I,II et III). Nous cherchions également à mettre au jour une allocation différentielle des mères suivant le sexe de leur jeune. Si le coût supérieur d'avoir un mâle par rapport à une femelle était évident quant aux taux de bouchées (CHAPITRE III), il s'est avéré plus difficile à détecter sur d'autres traits. À Anglesea, les jeunes mères avaient moins de probabilité d'avoir un jeune qui atteigne le stade 'LPY' après avoir eu un fils qu'une fille (CHAPITRE II). Toutefois, des résultats contraires à nos attentes ont été trouvés, du moins au premier abord, sur la croissance et le succès reproducteur subséquent. Ainsi, les femelles qui avaient eu une fille perdaient davantage de masse (CHAPITRE I) et avaient généralement une probabilité moindre de produire un jeune qui atteigne le stade 'LPY' ou qui soit sevré par la suite (CHAPITRE II). En revanche, l'intervalle de naissance n'était pas différent suivant le sexe du jeune alors qu'il était fortement affecté par le coût de la reproduction démontré grâce à la manipulation, invoquant une autre explication qu'un coût supérieur des filles par rapport aux fils. En effet, les femelles qui étaient en mauvaise condition corporelle gagnaient de la masse quand elles produisaient une fille, mais pas un fils (CHAPITRE I). De surcroît, les jeunes mères avaient moins de chances de sevrer un jeune à l'événement de reproduction suivant si elles avaient eu un fils plutôt qu'une fille, et le succès reproducteur des mères des fils n'était plus différent de celui des mères des filles dans les années plus difficiles (CHAPITRE II). Enfin, les mères des fils augmentaient la quantité de nourriture ingérée si elles avaient sevré un jeune l'année précédente, mais les mères des filles la diminuaient. Ces différents résultats suggéraient fortement qu'un ajustement du sexe-ratio était utilisé quand les ressources individuelles ou environnementales contraignaient davantage la reproduction. En conclusion, pour limiter le décalage entre les besoins énergétiques et la disponibilité en nourriture, les femelles chez le kangourou gris de l'Est pourraient modifier l'allocation de leurs ressources à la reproduction en reportant la prochaine mise bas et en produisant un jeune du sexe le moins coûteux en accord avec les contraintes individuelles et environnementales. Ces résultats soulignent l'importance d'études avec un suivi individuel sur plusieurs années afin de pouvoir comprendre la variabilité des stratégies de reproduction et leurs conséquences sur la dynamique des populations. // Abstract : Reproduction in living beings, particularly in female mammals that produce milk, is costly, potentially involving trade-offs with life-history traits if resources are limited and an increase in foraging effort. Individual differences may, however, hide the negative effects of this cost on life-history traits. I used two powerful and complementary approaches, to deal with individual heterogeneity: experimental manipulation of reproductive effort and statistical control of individual effect. Using both approaches, I investigated the effect of presence, size and sex of young on growth, subsequent reproduction and individual foraging behaviours of females. I used data of tagged free-ranging eastern grey kangaroos (Macropus giganteus) collected over six years at five study sites in Victoria, Australia. There was a clear cost of reproduction. Reproductive effort decreased mass gain and limb growth for inter-capture intervals greater than two years. Over two successive reproductive events, mass gain and arm growth were reduced but leg growth was independent of reproductive effort (CHAPTER II).In addition, survival to Large Pouch Young ('LPY') stage, about 7 months of age, was higher and birth rate lower in manipulated compared to control females but survival to weaning was not affected (CHAPTER III). CHAPTER IV shows that lactating females cope with current reproductive costs by increasing ivtime spent foraging as well as bite and chewing rates without decreasing vigilance comparedto non lactating ones. Bite rate was also greater for females that weaned a young at the previous reproductive event. My study supports reproductive cost hypothesis while showing substantial individual differences. To limit mismatch between energetic needs and resource availability, females of eastern grey kangaroo could modify resource allocation to reproduction by delaying birth date of subsequent young and producing the less costly sex according to individual and environmental constrains. My thesis shows the importance of experimental approach and individual monitoring over multiple years to understand the diversity of reproductive strategies and their consequences in evolutionary ecology and population dynamic.

R??sum?? : La reproduction entra??ne des d??penses ??nerg??tiques importantes chez les femelles mammif??res. Ces d??penses sont suppos??es diminuer l'??nergie disponible pour d'autres traits positivement corr??l??s ?? l'aptitude ph??notypique et augmenter les besoins d'alimentation. Toutefois, des diff??rences individuelles dans la capacit?? d'acquisition et d'allocation peuvent masquer l'impact n??gatif de l'effort reproducteur. La manipulation exp??rimentale de l'effort reproducteur et le contr??le statistique des effets individuels sont deux approches puissantes et compl??mentaires mises en ??uvre dans le cadre de mon ??tude afin de contr??ler pour l'h??t??rog??n??it?? individuelle. Elles ont permis de montrer clairement un co??t de la reproduction chez le kangourou gris de l'Est (Macropus giganteus). Dans un premier temps, nous avons trouv?? que le co??t de la reproduction affectait le montant d'??nergie allou?? ?? certaines fonctions somatiques (CHAPITRE I). L'effort reproducteur diminuait le gain de masse et la croissance des jambes pour des intervalles de capture sup??rieurs ?? deux ans. Chez les femelles non manipul??es, un effet n??gatif sur le gain de masse ??tait aussi observable pour un intervalle inf??rieur ?? 3 ans. ?? l'??chelle de deux ??v??nements successifs de reproduction, le gain de masse et dans une moindre mesure la croissance des bras, mais non des jambes diminuaient avec un effort reproducteur plus important ?? la pr??c??dente reproduction. Ensuite, nous avons d??montr?? qu'il y avait un co??t de la reproduction en terme de futur succ??s reproducteur (CHAPITRE II). Les individus dont l'effort reproducteur avait ??t?? diminu?? exp??rimentalement produisaient davantage de jeunes qui survivaient au stade 'LPY', ??g??s approximativement de 7 mois, que les femelles contr??les. Ils diminuaient ??galement davantage leur taux de reproduction en allongeant l'intervalle entre les naissances, mais la survie au sevrage n'??tait pas affect??e. Le CHAPITRE III montre que les femelles adaptaient leur comportement alimentaire en fonction de leur statut reproducteur. En comparaison avec les individus manipul??s ou ayant perdu leur jeune, les femelles allaitantes augmentaient leur temps pass?? ?? s'alimenter durant la journ??e, l'intensit?? de leurs bouch??es et de leur mastication sans impliquer de compromis avec la vigilance. Nous avons aussi d??couvert que la survie au sevrage du jeune pr??c??dent menait ?? une augmentation du taux de bouch??es pour l'ann??e en cours. Les CHAPITRES I et II ont mis en ??vidence l'effet non n??gligeable des diff??rences individuelles sur la d??tection des co??ts de la reproduction. En effet, en l'absence de manipulation exp??rimentale ou de contr??le statistique, aucun compromis n'??tait d??tect?? autant en terme de croissance que de prochaine reproduction. Au contraire, des corr??lations positives entre l'effort reproducteur et les autres traits ont ??t?? trouv??es. Le CHAPITRE I sugg??rait notamment que cette variabilit?? du succ??s reproducteur ??tait li??e ?? l'h??t??rog??n??it?? individuelle dans le gain de masse maternelle qui augmentait la survie du jeune. Dans le CHAPITRE II, une corr??lation positive entre les probabilit??s d'avoir un 'LPY' lors de deux ??v??nements successifs de reproduction sugg??rait que certaines femelles ??taient capables de mener ?? bien ou non leur reproduction, mais cela ind??pendamment de l'effort reproducteur pr??c??dent. Enfin dans le dernier CHAPITRE (III), l'effet al??atoire ??tait significatif dans l'analyse de diff??rents comportements d'alimentation, ce qui pourrait ??tre li?? aux diff??rences de gain de masse des femelles pr??sent??es dans le CHAPITRE I. Certaines contraintes individuelles affectant le co??t de la reproduction ont ??t?? identifi??es. La masse et la condition corporelle augmentaient le succ??s reproducteur et diminuaient l'intervalle entre deux naissances successives (CHAPITRES I et II), mais contrairement ?? de pr??c??dentes ??tudes le comportement d'alimentation des femelles n'??tait pas affect?? par leur masse (CHAPITRE III). L'??ge des individus avait ??galement une influence. Les jeunes femelles croissaient davantage, avaient aussi une prise alimentaire plus importante et subissaient un co??t de reproduction sup??rieur. Ce dernier se traduisait par un taux d'??chec plus ??lev?? ?? la reproduction suivante si les jeunes femelles avaient eu un jeune l'ann??e pr??c??dente (CHAPITRES I, II et III). Des contraintes environnementales fortes influen??aient la reproduction des femelles. La croissance, le succ??s reproducteur, l'intervalle entre les naissances et les comportements d'alimentation variaient suivant le site et l'ann??e d'??tude. Le site du Promontory et l'ann??e 2011 apparaissaient particuli??rement limitants. En effet en 2011, le gain de masse et le succ??s reproducteur ont diminu?? et l'intervalle de naissance et la prise de nourriture pour les femelles allaitantes ont augment?? (CHAPITRE I,II et III). Nous cherchions ??galement ?? mettre au jour une allocation diff??rentielle des m??res suivant le sexe de leur jeune. Si le co??t sup??rieur d'avoir un m??le par rapport ?? une femelle ??tait ??vident quant aux taux de bouch??es (CHAPITRE III), il s'est av??r?? plus difficile ?? d??tecter sur d'autres traits. ?? Anglesea, les jeunes m??res avaient moins de probabilit?? d'avoir un jeune qui atteigne le stade 'LPY' apr??s avoir eu un fils qu'une fille (CHAPITRE II). Toutefois, des r??sultats contraires ?? nos attentes ont ??t?? trouv??s, du moins au premier abord, sur la croissance et le succ??s reproducteur subs??quent. Ainsi, les femelles qui avaient eu une fille perdaient davantage de masse (CHAPITRE I) et avaient g??n??ralement une probabilit?? moindre de produire un jeune qui atteigne le stade 'LPY' ou qui soit sevr?? par la suite (CHAPITRE II). En revanche, l'intervalle de naissance n'??tait pas diff??rent suivant le sexe du jeune alors qu'il ??tait fortement affect?? par le co??t de la reproduction d??montr?? gr??ce ?? la manipulation, invoquant une autre explication qu'un co??t sup??rieur des filles par rapport aux fils. En effet, les femelles qui ??taient en mauvaise condition corporelle gagnaient de la masse quand elles produisaient une fille, mais pas un fils (CHAPITRE I). De surcro??t, les jeunes m??res avaient moins de chances de sevrer un jeune ?? l'??v??nement de reproduction suivant si elles avaient eu un fils plut??t qu'une fille, et le succ??s reproducteur des m??res des fils n'??tait plus diff??rent de celui des m??res des filles dans les ann??es plus difficiles (CHAPITRE II). Enfin, les m??res des fils augmentaient la quantit?? de nourriture ing??r??e si elles avaient sevr?? un jeune l'ann??e pr??c??dente, mais les m??res des filles la diminuaient. Ces diff??rents r??sultats sugg??raient fortement qu'un ajustement du sexe-ratio ??tait utilis?? quand les ressources individuelles ou environnementales contraignaient davantage la reproduction. En conclusion, pour limiter le d??calage entre les besoins ??nerg??tiques et la disponibilit?? en nourriture, les femelles chez le kangourou gris de l'Est pourraient modifier l'allocation de leurs ressources ?? la reproduction en reportant la prochaine mise bas et en produisant un jeune du sexe le moins co??teux en accord avec les contraintes individuelles et environnementales. Ces r??sultats soulignent l'importance d'??tudes avec un suivi individuel sur plusieurs ann??es afin de pouvoir comprendre la variabilit?? des strat??gies de reproduction et leurs cons??quences sur la dynamique des populations. // Abstract : Reproduction in living beings, particularly in female mammals that produce milk, is costly, potentially involving trade-offs with life-history traits if resources are limited and an increase in foraging effort. Individual differences may, however, hide the negative effects of this cost on life-history traits. I used two powerful and complementary approaches, to deal with individual heterogeneity: experimental manipulation of reproductive effort and statistical control of individual effect. Using both approaches, I investigated the effect of presence, size and sex of young on growth, subsequent reproduction and individual foraging behaviours of females. I used data of tagged free-ranging eastern grey kangaroos (Macropus giganteus) collected over six years at five study sites in Victoria, Australia. There was a clear cost of reproduction. Reproductive effort decreased mass gain and limb growth for inter-capture intervals greater than two years. Over two successive reproductive events, mass gain and arm growth were reduced but leg growth was independent of reproductive effort (CHAPTER II).In addition, survival to Large Pouch Young ('LPY') stage, about 7 months of age, was higher and birth rate lower in manipulated compared to control females but survival to weaning was not affected (CHAPTER III). CHAPTER IV shows that lactating females cope with current reproductive costs by increasing ivtime spent foraging as well as bite and chewing rates without decreasing vigilance comparedto non lactating ones. Bite rate was also greater for females that weaned a young at the previous reproductive event. My study supports reproductive cost hypothesis while showing substantial individual differences. To limit mismatch between energetic needs and resource availability, females of eastern grey kangaroo could modify resource allocation to reproduction by delaying birth date of subsequent young and producing the less costly sex according to individual and environmental constrains. My thesis shows the importance of experimental approach and individual monitoring over multiple years to understand the diversity of reproductive strategies and their consequences in evolutionary ecology and population dynamic.

The thesis concerns polyelectrolyte gels in contact with oppositely charged proteins and surfactant micelles, and includes of four papers (I-IV). In paper I confocal Raman spectroscopy was introduced as a method to trace micelles and investigate the structure of gel-surfactant complexes, in phase separated gel spheres. In paper II, the binding of surfactants to microspheres (~50-100 µm) was investigated by means of a micromanipulator-assisted microscopy method. The two surfactants were found to display qualitative difference respect to degree of swelling, surfactant distribution in the gels, and the difference is discussed in terms of absence/presence of hydrophobic attraction to the polyelectrolyte gel network. Kinetics of volume change in gels were analyzed. Aggregation numbers of micelles in polystyrenesulfonate (PSS) solutions, obtained from fluorescence quenching measurements, are presented. In paper III, phase behaviour, protein assembly and diffusion, was studied in PSS gel microspheres. Interpretation of results was aided by measurements of osmotic swelling of individual gel networks, and by combining the results with studies of protein diffusion in macroscopic (cm-sized) gel spheres. Complexes formed were further analyzed with small angle x-ray spectroscopy. In paper IV phase behaviour of mixed ionic/nonionic surfactant micelles is investigated in cm-sized gel spheres. The coexistence of three phases, the formation of dense shells in the bulk of the gels and other phenomena are described for the first time, and the results are presented along with discussion on the charge-density of spherical micelles and of  network induced hysteresis effects in gels. The composition and microstructure of phases are investigated by confocal Raman spectroscopy and small-angle x-ray scattering respectively. The results are interpreted with aid of highly detailed theoretical model calculations.

Timber harvesting results in patches of regenerating forest that are substantially different from surrounding unharvested stands, and provides an opportunity to investigate the effect of habitat change on forest fauna. In this thesis I used timber harvesting as an experimental treatment to investigate the effect of a changed resource base on the home range and resource selection of the swamp wallaby, Wallabia bicolor. I recorded habitat attributes at unharvested control, recently harvested (<12 months old), 5 year old and 10 year old sites. Initially, harvesting removed almost all above-ground plant biomass, although the nitrogen and water content of grass on recently harvested sites was relatively high. Five years after harvesting, sites were dominated by densely regenerating 1-3 m tall Eucalyptus seedlings. Relative to unharvested sites, there was substantial lateral cover and values of a forage quality index were high. In contrast, 10 year old sites supported dense, closed stands of 3-6 m tall eucalypt regeneration, had a moderate amount of lateral cover and had low values of the forage quality index. (For complete abstract open document)

The South Australian mainland tammar wallaby (Macropus eugenii eugenii) was presumed extinct in the wild from the early 1930's, until a feral population was re-discovered in New Zealand. Eighty-five animals were returned to Australia as part of a repatriation program into their former range. The establishment phase after a reintroduction is a critical time as animals may fail to survive if they cannot find resources and avoid predators in an unfamiliar habitat. To maximise reintroduction and establishment success, reintroductions need to be planned with a good understanding of the animals’ ecology and anti-predator strategies. To improve this understanding requires experimental reintroductions and detailed monitoring. This thesis investigates the experimental reintroduction of 46 wallabies into Innes National Park in South Australia and examines the influence of release group familiarity on establishment. Part of this was an investigation of home range, habitat requirements and social behaviours during establishment and seasonally post-establishment. The thesis includes three data chapters which focus on (1) home range and core area, home range stability and degree of overlap with conspecifics; (2) habitat selection at the landscape scale and for day and night use within home range; and (3) factors influencing fine scale habitat use and social grouping behaviours in light of predation risk. In this study, the animals’ perceived risk of predation is assumed to be reflected by surrogate measures of risk, such as distance to cover, likelihood of using cover, group size, and distance to nearest neighbour. Release group familiarity was established by housing animals together in captivity for at least one month prior to release (“familiar” groups), whereas “unfamiliar” release groups comprised animals housed separately but released together. After each reintroduction the first month was considered to be a time of “establishment” in the environment. During the establishment month, home ranges were not randomly located within the landscape, as indicated by the biased occupancy of particular habitat types. Habitat types selected at the landscape scale were similar for familiar and unfamiliar release groups. However, animals released in unfamiliar groups showed a stronger preference for denser high cover habitat during their nocturnal activities within their home range. As tammars use cover to conceal themselves from predators, this result suggests that animals released in unfamiliar groups were more cautious than those released in familiar groups. Indeed at the fine scale, it was also found that animals released in unfamiliar groups were more likely to be found in high cover habitat, and forage closer to cover at night than did those released in pre-established familiar groups. Using habitat with more caution and capitalising on communal vigilance in an unfamiliar habitat may ultimately improve the likelihood of survivorship and overall reintroduction success. Comparing habitat decisions and social behaviours during the establishment period to similar times of year post-establishment suggested that animals' naivety about their new environment influenced some decisions they made. While habitat selection at the landscape scale was similar during establishment and at an equivalent time of year post establishment, analyses showed that they preferred to use melaleuca (a high cover habitat) during their nocturnal activities during establishment much more strongly than they did once they had established. Home range and core areas were also significantly smaller during the establishment month than at an equivalent time of year post establishment. This result supports the idea that animals will restrict their movements when they are unfamiliar with the habitat and predation risks. It also suggests that some habitat choices improved once they were familiar with their new environment and presumably predation risks. Their habitat choices reflected better anti-predator behaviour than those made during the establishment period: they were more likely to use high cover habitat, they remained significantly closer to cover while foraging, and group sizes were larger than during establishment. Seasonal habitat selection at the landscape and home range scales suggested that the five habitat types within the study area provided different fundamental resources for the animals, as they were preferred at different times of year. Some differences in habitat selection were observed between the sexes, and the females were more selective in their diurnal and nocturnal activities. These differences most likely reflected, in part, differences in predator avoidance and reproductive strategies of the sexes, where females' preference at the landscape scale shifted towards high cover habitat during spring, the time of year when pouch young vacate the pouch and start to become independent. While no such selection at the landscape scale was observed for the males, it was also observed that within their daily activities both sexes were more likely to be found in high cover habitat during spring than any other time of the year, perhaps suggesting that as males were following the females. Overall, females generally selected Eucalyptus diversifolia, Acacia anceps and grassland at the landscape scale, and used E.diversifolia for refuge during the day and the other two habitats for foraging at night, whereas males generally preferred Melaleuca halmaturorum instead of E.diversifolia for diurnal refuge. Eucalyptus rugosa was mostly avoided by both sexes. From month to month, both sexes expanded rather than shifted their home ranges to incorporate new areas, and these new areas were explored with conspecifics (when the amount of new area increased the amount of sharing also increased), highlighting their reliance on communal vigilance when in unfamiliar habitat. More new areas were incorporated into home ranges from July to December than from January to May. Time since release was not influential, which also supported the conclusion that perhaps home ranges moved to follow resources or overlap conspecifics more. Indeed, in one circumstance when neighbouring animals had died, a male wallaby was observed to move four kilometres through unfamiliar habitat and completely shift his home range in search of other residence. Compositional analysis of habitat use versus availability indicated that monthly home ranges were selectively positioned in the landscape and were always larger than 4ha. Males' home ranges were larger than females', and males shared more of their home ranges than females did, supporting the usual sex bias observed for polygamous species. Core areas were proportional to the size of the home range, with similar sizes held by males and females and throughout the year. Core size was not influenced by the degree of overlap with conspecifics, with similar amount of core area shared by both sexes year round. The time of year influenced home range size, the smallest were held in winter when food resources were likely to be most abundant, but also when inclement weather was likely to restrict movements, as the animals' ability to detect predators may be hindered due to wet and windy conditions. Living with conspecifics is known to assist predator detection by group vigilance. Indeed, this study found the amount of home range overlap and the time two individuals spend together was positively correlated, and the size of home ranges decreased when more of it was shared with conspecifics, which suggested that sharing of home range was important. The degree which home ranges were shared was observed to be a fairly stable requirement for both sexes and did not change with season or time since release. Despite previous isolation from predators, the wallabies displayed anti-predator behaviours which incorporated interrelated benefits obtained from group vigilance and using protective cover. Additionally, these behaviours were adjusted according to their familiarity with the habitat. Post-establishment, animals were observed to go further from cover when they were a greater distance from their nearest neighbour but surrounded by larger numbers of conspecifics. Whereas during the establishment period, animals ventured further from cover when they were closer to a nearest neighbour, but group size was not influential. It is known that larger groups of animals have more false alarms to predators, and false alarms result in the animals‟ wasting energy in fleeing. If false alarms are more prevalent while occupying unfamiliar habitat with unfamiliar risks, then relying on large numbers of conspecifics while establishing may have been more of a liability than a benefit during the establishment period. However, some anti-predator strategies were commonly used, regardless of familiarity with their habitat. During the establishment month and post-establishment, animals were always more likely to be found in high cover habitat when they were further from their nearest neighbour, or were surrounded by fewer conspecifics. Some strategies and habitat decisions may have reflected differences in reproductive needs. While females, with and without pouch young did not differ in how far they would forage from protective cover, females with pouch young remained closer to their nearest neighbour than those without. This finding perhaps reflected the importance of relying on communal vigilance when their flight time from a predator may be hindered due to increased weight and bulk of a pouch young. These findings supported the theory that group vigilance anti-predator strategies are somewhat innate in the tammars, as having previously been completely isolated from predators their responses could have been lost, and once released there was no opportunity to socially learn the appropriate responses off an established population. Some habitat and social grouping behaviours were occasionally unexpected but may have been balanced out by other behaviours. This study observed that animals foraged further into the open during winter than at any other time of year, which contradicts findings by other authors where tammars foraged further into the open when the weather was fine. However, I also found that animals remained closer to their nearest neighbour during autumn and winter than at any other time of year. Perhaps foraging further into the open in inclement weather is actually safer if it provides a greater chance to detect and react to an approaching predator. For example, a fox approaching from the scrub edge would not give the wallaby enough time to respond. An additional benefit of foraging further away from cover in larger group sizes, is that animals can flee in different directions confusing the fox, as it would have to make a quick decision and chose one animal to pursue. Animals were furthest from their nearest neighbours in spring which was also somewhat surprising as this is when pouch young vacate the pouch and it was observed that females with pouch young remain closer to their nearest neighbour suggesting they gain some anti-predator benefit from doing so. However, during spring the animals were also more likely to be found in high cover habitat than at any other time of year, so this may have somewhat balanced out the need for a close neighbour. Overall, this study confirmed that tammars retain anti-predator behaviours despite previous isolation from predators. However, their habitat and social decisions improved with time since release. In this experimental study, animals released in groups with unfamiliar conspecifics appeared to be at an advantage as they displayed habitat use and social groupings which suggested they were using their new habitat with more caution. Therefore, this study recommends releasing groups of unfamiliar conspecifics. Releasing animals at different times of year also had an influence on how they used their habitat. Animals released in spring displayed behaviours suggesting that they were more cautious in avoiding predators: they were more likely to be found in cover, foraged closer to cover, and were in larger group sizes than those animals released in winter. Therefore, it is recommended that animals are released at a time of year where conditions are fine and resources are abundant. Releasing females with pouch young did not appear to hinder the animals after their release (compared to females without pouch young) and could be recommended as young permanently evacuating the pouch in the wild are at a greater advantage than juveniles released from captivity. Results from this experimental study were used to assist ongoing management decisions and were imperative in the planning of subsequent reintroduction events for this species, and can be applied more generally to other species with similar anti-predator strategies.
Thesis (Ph.D.) -- University of Adelaide, School of Earth and Environmental Sciences, 2011

碩士
國立臺北教育大學
自然科學教育學系碩士班
95
This experiment, from February 2006 to January 2007, was designed to learn the habit and breeding behavior of Macropodus opercularis (Linnaeus) in an artificial environment. Paradise fish’s behaviors were categorized into nine patterns in this experiment. Among these patterns, swimming took 47.6%, feeding took 20.4%, motionless took 17.8%, and the rest behavior patterns including surfing to breath, building nest, taking care of larvae, waving the fins, and waving the fins and body without moving around. Paradise fish’s behavior patterns are closely related to environmental temperature. The percentage of active behaviors during 14℃~18℃ would take only 37.33% of the period of observation; and when the temperature moved up to 29℃~32℃, it would also increase to 90.26%. Temperature also influenced the usage of space of paradise fish. They tended to perform most of their behaviors near the surface area. When being disturbed, they would move to the bottom of the water area fast and hold still there. With the increase of temperature, paradise fish’s fighting behavior tends to be faster and more furious. It usually ended within 30 minutes and the advantage lied in the previous habited paradise fish.This experiment also discussed the influence of temperature on paradise fish’s breeding behavior. When food sources were abundant and the water temperature was above 22℃, male paradise fish would start to produce foam to build up its nest. Under the influence of low temperature, female paradise fish would not lay eggs unless the temperature was increased by heating facility to 26℃. However, if the temperature was kept steady at 26℃, the female paradise fish would not lay eggs, either. The temperature had to be lowered for at least one week before it could be raised again to induce female paradise fish to lay eggs. After the eggs were laid and fertilized, if the temperature increase in the following days were lower than 0.2℃ a day, the number of larvae hatched in the nest would be very low or even none; on the contrary, if the temperature increase could be more than 0.8℃ a day, the number of larvae could be effectively improved. The differences could be as huge as 250 to 1127. When discussing the survival rate of larvae, this experiment confirmed that small Cyclops would be the most suitable feed for larvae. If the water quality was stable and food source was sufficient, survival rate of larvae could be more than 90%.

碩士
國立中山大學
海洋生物研究所
91
Animal agonistic behaviors, including threat, combat, submission and chase, are complex responses to experimental stimuli. Animal behaviors are regulated by the central nervous system. In the central nervous system, the biogenic amine serotonin has been thought to serve important roles in animal aggression (including fish), but it’s not clear if serotonin affects threatening and fighting differently. This study took experimental approaches to examine the effects of this neurotransmitter on threatening and fighting in a paradise-fish model in which the complex agonistic behavior is well characterized. Treatments with serotonin synthesis precursor tryptophan (0.125mg/g) to one of the two contestants had insignificant effects on threatening or fighting while synthesis blocker p-Chlorophenylalanine (PCPA) (0.3mg/g) decreased threatening time and occurrences of head-tail display. When these drugs were added to both contestants, tryptophan reduced all agonistic behavioral patterns displays, and PCPA decreased threatening time and head-tail display. In addition to changes in behavioral patterns, tryptophan led the fish to be attacked. In contrast, PCPA led the injected fish to actively attack its opponent. However, tryptophan and PCPA had no effect on social status in parasise fish. I suggest that agonistic responses and the initial fighting decision in a paradise fish are affected not only by level of its serotonin, but also by the behavioral responses of its opponent. And the establishment of outcome of encounter is affected more by the environmental stimuli than the serotonin level.

碩士
國立臺灣師範大學
生命科學研究所
100
An individual’s reproductive success can depend on its morphological, behavioral and hormonal traits. Although many studies have explored the importance of each of these three individually to reproductive success, how they combine and how males’ and females’ traits combine to influence reproductive success are rarely explored. I paired up male and female paradise fish Macropodus opercularis to investigate (1) whether male and female fishes’ behavioral traits are related to their morphological traits and hormone levels, and (2) the relative importance of the three types of traits in both the male and the female in determining the reproductive success of a mating pair. I used standard length, condition factor and caudal fin length to represent the fishes’ morphology; aggressiveness (attack frequency) and parental care (bubble-nest area) to represent their behaviors; levels of testosterone (T), 11-ketotestosterone (KT), 17ß-estradiol (E2) and cortisol (Cort) to represent their hormones, and likelihood of spawning, latency to spawn and the number of eggs they produced to represent reproductive success. I had five main sets of results. (1) Egg production was associated positively with the female’s KT levels and the male’s T levels, but negatively with female’s T levels and the male’s KT levels. (2) Males with high levels of T built small bubble-nests. Moreoever, female partners of males which built smaller bubble-nests spawned more slowly. (3) Females with higher levels of Cort were slower to spawn. (4) Female partners of males with greater condition factor were less likely to spawn, and partners of males with longer standard length produced fewer eggs. (5) Males with longer caudal fins were less aggressive, and females with longer standard length were more aggressive. Overall, this study showed that males which provided more parental care or had higher levels of T had higher reproductive success, but that larger males or those with higher levels of KT had lower reproductive success. Moreover, females with high levels of KT had high reproductive success, but those which had higher levels of T or Cort had lower reproductive success. In conclusion, the morphological traits and hormone levels of male and female paradise fish were related to their aggressiveness and parental effort. A pair’s reproduction was correlated with both the male and female fishes’ traits. Morphological traits and hormone levels were more important than aggressiveness and parental effort, and males’ traits had a stronger association with reproduction than females’.

This authoritative volume represents a complete and comprehensive guide to the husbandry of Australian marsupials and other mammals. Australian Mammals: Biology and Captive Management dedicates a chapter to each group of animals including the platypus, the echidna, carnivorous marsupials, numbats, bandicoots and bilbies, koalas, wombats, possums and gliders, macropods, bats, rodents and the dingo. For each animal group the following information is covered: Biology; Housing; Capture and restraint; Transport; Diet; Breeding; Artificial rearing; and Behaviour and behavioural enrichment. The book provides a complete literature review of all known information on the biology of each group of animals and brings information on their biology in the wild into captive situations. Also, for the first time, it provides practical guidelines for hand-rearing, and has been extensively reviewed by zookeepers and veterinarians to incorporate the most up-to-date information and techniques. Australian Mammals: Biology and Captive Management provides practical guidance for zoo-keepers, veterinarians, zoologists, researchers and students. Winner of the 2004 Whitley Medal. Shortlisted in the Scholarly Reference section of the 2004 Australian Awards for Excellence in Educational Publishing.

Abstract Billions of tons in proven reserves for inter-salt shale oil has been recognized as crucial strategic resources. The fracturing fluids injection triggers unique salt dissolution chemical phenomena, which on the one hand improves the reservoir pore structure and on the other hand easily induces formation collapse. However, there is no research on triggering mechanism and controlling factors of salt dissolution, and effect of slat dissolution on extremely important imbibition function in inter-salt shale formation is lack of understanding. Herein, the complex mechanism of inter-salt shale dissolution reaction was revealed based on microcosmic pore structure network. The effect of salt dissolution on imbibition in inter-salt shale formation was assessed from various angles, which was conducted by online nuclear magnetic resonance (NMR), high-quality focused ion beam scanning electron microscopy (FIB-SEM), and CT technologies. The results indicate that high temperature improves slat dissolution reaction and enhances the seepage capacity by more than 60 times, which sharply exceeds the influence of fracturing fluid salinity, flow rate and pressure in inter-slat formation. Three kinds of pores for imbibition recovery contribution were 48.17%, 46.39%, and 5.44%, namely micropore, mesopore and macropore, respectively. Additionally, salt dissolution enlarged seepage channel so that spontaneous imbibition occurred in micropores, which was considered as conventionally unmovable areas. Besides, the salt dissolution effect mainly promoted oil discharge in the second stage of imbibition process, leading to 15.83% higher imbibition recovery. These results can furnish an in-depth understanding the nature of complicated mechanisms in inter-slat shale oil reservoirs with fracturing fluids injection.

Abstract Billions of tons in proven reserves for inter-salt shale oil has been recognized as crucial strategic resources. The fracturing fluids injection triggers unique salt dissolution chemical phenomena, which on the one hand improves the reservoir pore structure and on the other hand easily induces formation collapse. However, there is no research on triggering mechanism and controlling factors of salt dissolution, and effect of slat dissolution on extremely important imbibition function in inter-salt shale formation is lack of understanding. Herein, the complex mechanism of inter-salt shale dissolution reaction was revealed based on microcosmic pore structure network. The effect of salt dissolution on imbibition in inter-salt shale formation was assessed from various angles, which was conducted by online nuclear magnetic resonance (NMR), high-quality focused ion beam scanning electron microscopy (FIB-SEM), and CT technologies. The results indicate that high temperature improves slat dissolution reaction and enhances the seepage capacity by more than 60 times, which sharply exceeds the influence of fracturing fluid salinity, flow rate and pressure in inter-slat formation. Three kinds of pores for imbibition recovery contribution were 48.17%, 46.39%, and 5.44%, namely micropore, mesopore and macropore, respectively. Additionally, salt dissolution enlarged seepage channel so that spontaneous imbibition occurred in micropores, which was considered as conventionally unmovable areas. Besides, the salt dissolution effect mainly promoted oil discharge in the second stage of imbibition process, leading to 15.83% higher imbibition recovery. These results can furnish an in-depth understanding the nature of complicated mechanisms in inter-slat shale oil reservoirs with fracturing fluids injection.