Wildlife and Species Interactions

Seed dispersal strategies and the threat of defaunation in a Congo forest

Background

Seed 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.

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Defaunation of Large-Bodied Frugivores Reduces Carbon Storage in a Tropical Forest of Southeast Asia

Background

Tropical forests are vital for carbon storage, but recent studies suggest that defaunation—the loss of large-bodied seed dispersers due to hunting and habitat fragmentation—can significantly impact this function. While previous research has shown reductions in above-ground carbon storage due to defaunation in South America and Africa, its effects on Southeast Asian forests remain debated. Some scientists argue that the dominance of wind-dispersed Dipterocarpaceae trees in the region buffers against carbon losses from defaunation. This study examines the extent to which defaunation influences carbon storage in a tropical forest in Thailand, where large frugivores such as primates, hornbills, and terrestrial mammals still persist.

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Drivers and spatial patterns of avian defaunation in tropical forests

Background

Tropical 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.

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Using Janzen–Connell to predict the consequences of defaunation and other disturbances of tropical forests

Background

The 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.

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Cascading effects of contemporaneous defaunation on tropical forest communities

Background

Defaunation, 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.

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Defaunation affects carbon storage in tropical forests

Background

Tropical forests play a critical role in global carbon storage, holding approximately 40% of the Earth's terrestrial carbon. While deforestation, logging, and climate change are well-documented threats to these forests, the impact of defaunation (the loss of large frugivorous animals due to hunting and habitat loss) has been largely overlooked. Many large-seeded hardwood trees rely on large vertebrates for seed dispersal, and their decline could significantly affect forest composition and carbon storage.

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A technological biodiversity monitoring toolkit for biocredits

Background

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Alnus acuminata: Valuable Timber Tree for Tropical Highlands

Background 

Alnus acuminata, also known as alder, is a nitrogen-fixing tree native to tropical highlands from Mexico to northern Argentina. It thrives in elevations between 1,200 and 3,200 meters, with annual rainfall of 1,000 to 3,000 mm and temperatures ranging from 4°C to 27°C. This species plays a significant role in watershed protection, soil enrichment, and sustainable timber production. Its adaptability to moist soils, including riverbanks and landslides, and its resilience in disturbed areas make it a valuable pioneer species. Farmers in regions like Costa Rica have used Alnus acuminata in agroforestry systems for over 90 years, integrating it with pastureland and coffee cultivation.

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Discolouring the Amazon Rainforest: how deforestation is affecting butterfly coloration

Background

Butterflies are among the most colorful organisms in the world, and color plays a central role in many of their life-history strategies. However, sudden environmental changes, including anthropogenic disturbances such as habitat loss and fragmentation, could affect the efficacy of coloration strategies in these and other animals. Therefore, this study aims to investigate how deforestation is affecting butterfly coloration in the Amazon Rainforest and to provide insights into the potential consequences of anthropogenic disturbances on these beautiful creatures.

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Lowland Tapirs Facilitate Seed Dispersal in Degraded Amazonian Forests

Background:

During their first decades of growth, secondary tropical forests have the potential to accumulate significative more carbon than old-growth stands. Nevertheless, recovering degraded forests' habitats could be an expensive task to achieve. In this context, natural regeneration processes, such as seed dispersal by herbivorous animals, offer a cost-effective tool to recover degraded forests, although this role remains largely unexplored.

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