The time it takes seeds to pass through the gut of vertebrates is an important aspect of endozoochorous seed dispersal because it influences seed dispersal distance. The physical characteristics of seeds (e.g. dry seed weight, volume and specific gravity) vary among plant species, which might cause a difference in seed movement through the gastrointestinal system. We conducted feeding experiments with captive female Japanese macaques Macaca fuscata (n=5) using eight different types of seeds to evaluate the effects of the physical characteristics of seeds on their passage time. The median seed recovery percentage for the real seeds was 35.5% (range, 24–78%). Among three passage time variables examined, the mean retention time (MRT) (37–54 h) and time of last appearance of a seed (TLA) (53–109 h) differed significantly among seed types, and the former differed significantly among individuals. Transit time (TT) (22–35 h) did not. The generalized linear models (GLM) selected dry seed weight as the most important factor affecting MRT, and specific gravity of seeds as the most important factor affecting TLA. This implies that (1) heavier seeds and (or) seeds with greater specific gravity remain in the gut longer and are likely to be dispersed farther from the parent plant; (2) the lighter seeds and (or) seeds with lower specific gravity are dispersed nearer the parent. Our study demonstrated the importance of considering the effects of the physical characteristics of seeds on the manner in which primates disperse plant species, although we should consider the effect of the individual variation in the passage time, too.
Endozoochory is important to the dynamics and regeneration of forest ecosystems. Despite the universality of inter-annual variation in fruit production, few studies have addressed the sign (seed predation versus seed dispersal) and strength (frequency and quantity) of fruit-frugivore interaction and the effectiveness of endozoochory in response to the long-term temporal context. In this study I evaluated the characteristics of endozoochorous dispersal by wild Japanese macaques Macaca fuscata inhabiting deciduous forest in northern Japan for five different years. I collected 378 fecal samples from the macaques in fall (September to November) and quantified the proportion of feces containing seeds, number of seeds per fecal sample, ratio of intact seeds, and seed diversity. The proportion of feces containing seeds of any species (five-year mean: 85.9%, range: 78–97%) did not show significant inter-annual variation, while species-level proportions did. The intact ratio of seeds (mean: 83%, range: 61–98%) varied significantly both between years and between months, and this varied among dominant plant species. The number of seeds per fecal sample (mean: 78, range: 32–102) varied monthly but did not between years, and the seed diversity (mean: 0.66, range: 0.57–0.81) did not show significant inter-annual variation, both of which were attributed to longer duration of macaques’ gastro-intestinal passage time of seeds exceed their feeding bouts. This study demonstrated that frequency and success of seed dispersal over seed predation of macaque endozoochory showed inter-annual variation, indicating low specificity across the seed–macaque network. The temporal variability in the quality of seed dispersal may provide evidence of high resilience in response to fluctuating environmental conditions in the temperate forests.
Abstract In Li‐Zellen mit Li‐Anode und organischem Elektrolyten [1 M LiClO 4 in Propylencarbonat‐1,2‐Dimethoxyethan (1:1 im Gewicht)] wurde das Ladungs‐ und Entladungsverhalten für (Li‐inkorporierende) Kathoden aus Cr 2 O 5 , Cr 3 O 8 und amorphem Cr‐oxid ["a‐Cr 3 O 8 " aus Wärmebehandlung von Cr 3 O 8 /Wasser‐Mischungen bei 110‐300°C] untersucht.
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