Forest Dynamics
Basin-Wide Effects of Game Harvest on Vertebrate Population Densities in Amazonian Forests: Implications for Animal-Mediated Seed DispersalBackgroundTropical forest ecosystems depend heavily on animal-plant interactions, particularly seed dispersal by vertebrates. However, widespread hunting in the Amazon has led to a significant decline in populations of many vertebrate species, especially large-bodied frugivores that are crucial for dispersing seeds of large-seeded plant species. While some vertebrate species are more sensitive to hunting than others, the cumulative impact of hunting across the Amazon basin remains poorly quantified. This study seeks to understand how subsistence hunting affects vertebrate populations and, by extension, the ecological services they provide, especially seed dispersal. Open access copy available |
Quantifying the Impacts of Defaunation on Natural Forest Regeneration in a Global Meta-AnalysisBackgroundIntact forests provide critical ecosystem services, such as carbon storage and climate regulation, which are heavily dependent on interactions between woody vegetation and animal species. However, defaunation is altering these interactions at a global scale. While previous studies have explored the effects of defaunation on individual ecosystems, a comprehensive global analysis quantifying its impact on natural forest regeneration has been lacking. This study conducts a meta-analysis to assess how vertebrate loss influences forest regeneration across multiple regions and ecosystems, identifying key taxonomic groups and ecological processes most affected by defaunation. Available with subscription or purchase |
Synergistic Effects of Seed Disperser and Predator Loss on Recruitment Success and Long-Term Consequences for Carbon Stocks in Tropical RainforestsBackgroundDefaunation—the loss of animal species due to hunting, habitat destruction, and other anthropogenic activities—has far-reaching consequences for tropical forests. Large frugivores play a crucial role in seed dispersal, while seed predators influence recruitment success and plant population dynamics. Previous studies have primarily focused on how defaunation affects seed dispersal, often overlooking the role of seed predators and potential compensatory effects within ecosystems. This study examines how the simultaneous loss of seed dispersers and seed predators affects tree recruitment and long-term carbon storage in tropical forests. Open access copy available |
Contrasting Effects of Defaunation on Aboveground Carbon Storage Across the Global TropicsBackgroundOpen access copy available |
Fungi and Insects Compensate for Lost Vertebrate Seed Predation in an Experimentally Defaunated Tropical ForestBackgroundDefaunation, primarily caused by overhunting, is known to disrupt critical plant-animal interactions such as seed dispersal and seed predation. This can have cascading effects on plant regeneration, species composition, and even carbon storage. While previous studies have focused on the negative consequences of losing vertebrate seed dispersers and predators, it remains unclear whether other organisms, such as fungi and insects, can compensate for these losses. This study explores whether the decline of large vertebrate seed predators in a tropical rainforest is offset by increased seed predation from non-vertebrate sources, specifically insects and fungi. Open access copy available |
Size-Related Differential Seed Predation in a Heavily Defaunated Neotropical Rain ForestBackgroundDefaunation, driven by hunting and habitat loss, disproportionately affects medium and large mammals, often leaving behind a residual community dominated by small rodents. This shift in mammal communities can alter seed predation dynamics and impact forest regeneration. In heavily defaunated areas like Los Tuxtlas, Mexico, small rodents have become the primary seed predators. This study investigates whether seed predation patterns differ based on seed size in a highly defaunated forest. Specifically, it examines whether small rodents preferentially consume small seeds while large-seeded species escape predation, potentially influencing seed germination and plant recruitment. Open access copy available |
Seed dispersal strategies and the threat of defaunation in a Congo forestBackgroundSeed dispersal is a crucial ecological process that shapes plant communities and maintains biodiversity in tropical forests. In the Congo Basin, most tree species rely on animals (zoochory) to disperse their seeds, with large vertebrates like forest elephants and bonobos playing a key role. However, hunting and poaching threaten these seed dispersers, which could have cascading effects on forest structure and plant regeneration. This study investigates the extent of animal-mediated seed dispersal in the LuiKotale forest, located in the Democratic Republic of the Congo (DRC), and assesses how hunting pressure on frugivores may impact tree community composition. Available with subscription or purchase |
Drivers and spatial patterns of avian defaunation in tropical forestsBackgroundTropical forests harbor an immense diversity of bird species, but hunting and wildlife trade are driving widespread declines in bird populations. Unlike habitat loss, hunting often occurs in seemingly intact forests, making its impact more difficult to detect. Birds are harvested for both subsistence (food) and commercial purposes (pet trade), but the spatial extent and drivers of avian defaunation remain poorly understood. This study aims to assess the factors influencing bird population declines and map defaunation patterns across tropical forests. Open access copy available |
Using Janzen–Connell to predict the consequences of defaunation and other disturbances of tropical forestsBackgroundThe Janzen–Connell (J–C) model describes how seed dispersal and mortality shape tropical forest diversity. According to the model, seeds that fall close to their parent trees suffer high mortality due to host-specific predators, pathogens, and herbivores. In contrast, seeds dispersed farther away have a better chance of survival. Defaunation, particularly the loss of large-bodied seed dispersers, disrupts this balance by reducing seed dispersal distances. This study applies the J–C model to predict how defaunation and other disturbances affect tree recruitment and forest composition. Available with subscription or purchase |
Cascading effects of contemporaneous defaunation on tropical forest communitiesBackgroundDefaunation, caused by hunting and habitat fragmentation, is a major threat to biodiversity in tropical forests. It disproportionately affects large-bodied vertebrates, which play key roles as seed dispersers, seed predators, and herbivores. The loss of these animals can have cascading effects on plant populations, altering species composition, seed dispersal, and plant recruitment. This study reviews empirical evidence from 42 studies to understand how defaunation influences plant-animal interactions, plant demography, and overall community diversity. Available with subscription or purchase |
