Fruit type has a major impact on seed dispersal, seed predation and energy allocation, but our understanding of large‐scale patterns in fruit type variation is weak. We used a dataset of 4008 Australian species to provide the first continental‐scale tests of a series of hypotheses about the factors that might affect fruit type. We found a significant latitudinal gradient in the proportion of fleshy‐fruited species, with the percentage of fleshy‐fruited species rising from 19% at 43.75°S to 49% at 9.25°S. Species bearing fleshy fruits were more frequent on the coastal fringes of Australia, while species bearing non‐fleshy fruits became more frequent toward the arid centre. Wet, warm and stable climates favoured fleshy‐fruited species, with the two best predictors of the proportion of fleshy‐fruited species being maximum precipitation over five days (R2 = 0.40), and precipitation in the wettest month (R2 = 0.25). These results remained consistent after accounting for phylogenetic correlation among species. A combined model including variables of precipitation, temperature, and climatic variation explained 67% of the variation in the proportion of fleshy‐fruited species. Our results are consistent with the idea that plant reproductive strategies are more often tied to conditions during the parts of the year in which they grow than to conditions during the harsh parts of the year. Overall, our findings demonstrate strong relationships between plant reproductive traits and environmental gradients, and improve our understanding of the factors that shape large‐scale patterns in plant ecological strategies.

Aim It has been widely assumed that large seeds generally require large animals to ingest and disperse them. However, this relationship has only been quantified in single animal groups (e.g. birds) and in a few communities. Our goal was to provide the first broad-scale study of the relationship between animal body mass and ingested seed size.Location Global. MethodsWe compiled a dataset of 13,135 unique animal × seed interactions, animal body masses and seed sizes in these interactions, across all vertebrate groups (fish, amphibians, reptiles, birds and mammals). ResultsContrary to expectations, ingested seed size was negatively related to animal body mass. This negative relationship was largely driven by large ungulates ingesting small and dry seeds, and analyses excluding either ungulates or seeds with non-fleshy fruit types showed a positive relationship between animal body mass and ingested seed size. Large animals ingested both seeds with a larger maximum size (the 95th quantile had a positive slope) and a smaller minimum size (the 5th quantile had a negative slope). Larger animals ingest larger seeds from fleshy fruits but smaller seeds from non-fleshy fruits. A significant positive relationship was found between animal size and the number of seed species ingested. Main conclusionsOur data show that one of the assumptions that has underpinned the study of animal-seed interactions does not hold true across the full range of animal taxa and fruit types. These findings shed new light on theories about which types of plant species might be at risk if large animals go extinct, and cast doubt on the generality of a few theories (e.g. optimal diet theory, fruit-size hypothesis) about the relationship between frugivores and seeds.

Aim Biotic interactions have traditionally been predicted to be stronger towards the tropics. However, all previous studies about the latitudinal gradient in seed predation were either based on single species or compiled data from studies that used different methods in different ecosystems. Our goal was to provide the first broad‐scale quantification of the latitudinal gradient in seed predation at both cross‐species and within‐species levels. Location Twenty‐five sites spanning 28° of latitude on the east coast of Australia. Methods Using consistent protocols, we measured pre‐dispersal seed predation for 256 species × site combinations (including a total of 170 species) and post‐dispersal seed removal for 126 species × site combinations (including a total of 91 species), as well as removal of standard rice grains at each site. The relationships between seed predation and latitude were quantified using generalized mixed‐effects models and meta‐analyses. Results Contrary to expectations, the proportion of seeds lost to pre‐dispersal seed predation increased with latitude at the cross‐species level and showed no latitudinal trend at the within‐species level. There was no significant relationship between latitude and the proportion of seeds lost to post‐dispersal seed removal, either within species or across species. We found significantly higher removal of standard rice grains at lower latitudes, but this trend reversed if we excluded the four island sites from analysis. Main conclusions Seed predation on natural seeds was not higher at lower latitudes. Thus, our study joins a growing body of evidence contrary to the idea that tropical species suffer greater losses to herbivores than do temperate species. The latitudinal gradient in removal rates for standard rice grains suggests that natural seeds from low latitudes may have achieved a similar predation rate to high‐latitudinal species through increased investment in defenses. However, additional data will be necessary to test this hypothesis.