Seeing the Forest for the Trees

Before diving deeper, let’s clarify some terms. Species richness refers to the number of different species in a specific area, while species abundance indicates how many individuals of each species are present. Evenness describes the distribution of individuals among the species in a community.

Petra Tschakert and colleagues define biodiversity as "a measure of variation and richness of living organisms at a particular scale." Vicki Medland’s definition aligns closely, focusing on genetic variation within species, species diversity, and ecosystem variety.

The Convention on Biological Diversity elaborates further, describing biodiversity as "the variability among living organisms from all sources, including terrestrial, marine, and other aquatic ecosystems, along with the ecological complexes of which they are a part."

Ian Swingland emphasizes that geographical areas influence biodiversity through the diversity of species, endemic species, and the degree of threat they face. He notes that the varying significance of these factors complicates defining biodiversity, creating barriers to effective problem-solving and decision-making.

While defining biodiversity can be challenging, two commonly used metrics for measuring it are the Shannon-Wiener function and Simpson’s Diversity Index. The Shannon-Wiener function accounts for both species richness and evenness, while Simpson’s index assesses the likelihood that two randomly chosen individuals belong to the same species.

A general trend in biodiversity is that ecosystems tend to be less diverse as one moves toward higher latitudes. This could be attributed to a greater abundance of life in the tropics during the last glacial period and a higher energy influx at the equator.

Specific regions, known as biodiversity hotspots, require urgent attention due to their concentrated biological richness and significant threats from human activities. Although these hotspots cover only 2.4% of Earth's land, they harbor over half of all vascular plants and 43% of land vertebrates unique to these areas.

For instance, Madagascar has around 90% of its plant and animal species endemic but has lost nearly 90% of its forests. Similar situations can be observed in the Tropical Andes and Sundaland, where substantial habitat loss has occurred.

In the following sections, we will explore the importance of biodiversity concerning climate change and its connection to emerging diseases.

The Interconnection with Climate Change

Restoring or conserving natural habitats like forests can significantly aid in removing carbon dioxide from the atmosphere. Research by Yin Li et al. suggests that conserving biodiversity in subtropical forests enhances tree carbon storage.

Reducing atmospheric CO? levels alleviates the warming effects of greenhouse gases and contributes to lower air pollution-related deaths, as demonstrated by Mark Jacobson's research.

Furthermore, Rachel Standish and Suzanne Prober highlight that diverse plant species offer additional benefits like improved soil carbon storage and ecological resilience.

Agroforestry, a land-use practice that integrates trees and crops, shows the highest potential for carbon sequestration according to Shibu Jose and Sougata Bardhan. Research on Arabica coffee production in Ethiopia by Olivier Honnay et al. indicates that agroforestry also supports biodiversity.

Scientists Qiang Fang and Shuangquan Huang assert that biodiversity is crucial for sustaining pollination, with over 80% of wild plant species relying on insects for reproduction.

On a more molecular level, studies have linked methane, a potent greenhouse gas, to the gut microbiome composition of livestock. Research by Juan Boo Liang and colleagues suggests that a diverse gut microbiome in livestock might be associated with reduced methane emissions.

Genetic Diversity and Its Implications

Glenn Yannic et al. argue that climate change forces animal species to contract their habitats, leading to a loss in genetic diversity. Research on the endemic Madagascan pea plant Delonix decaryi by Malin Rivers et al. shows a similar trend in decreasing genetic diversity with habitat loss.

Additionally, Camilla Wikenros and others reveal that reduced species abundance can foster inbreeding, which may push species toward extinction. Investing in species abundance is crucial for enhancing individual fitness and preventing extinction, as genetic diversity is fundamental for species adaptation.

While the application of genetic data in biodiversity conservation is still limited, researchers like Malin Rivers et al. are working to bridge this gap, believing that genetic analyses can improve our understanding of ecological impacts of population changes.

Aquatic Biodiversity

Focusing on marine environments, Jonathan Lefcheck et al. find that marine biodiversity is a strong predictor of fish biomass globally. Conversely, Tim McClanahan and Catherine Jadot’s research on Madagascar’s coral reefs indicates that fish species richness is significantly influenced by biomass.

This relationship is vital, especially since billions rely on fish for their protein intake.

In the Coral Triangle of Southeast Asia, Susan Williams et al. advocate for multispecies seagrass restoration to enhance plant survival and coverage, crucial for local fisheries and coastal protection.

Despite these positive aspects, some studies, including those by Michaela Zeiter et al. and Aliny Pires et al., fail to show that diverse ecosystems consistently protect against climate change impacts.

Pandemic Patterns

Isabel dos Santos Silva et al. describe pandemics as widespread epidemics affecting many people across borders. Over the last century, their frequency has increased due to global travel, urbanization, and greater human interaction with the environment.

Dirk Schmeller et al. highlight that rising pathogen emergence is linked to climate change, biodiversity loss, and habitat degradation. Notably, 75% of new infectious diseases in humans are zoonotic, originating from animals.

The relationship between biodiversity and disease emergence is intricate. The "dilution effect" suggests that higher biodiversity reduces the risk of disease transmission, as shown by Serge Morand’s research linking declining biodiversity to human infectious disease outbreaks.

For example, the West Nile virus has not caused significant epidemics in areas with high viral host richness, as noted by Alex Byas and Gregory Ebel.

However, greater biodiversity can also contribute to disease emergence. Research by Denis Valle and James Clark indicates that forest conservation in the Brazilian Amazon correlates with increased malaria cases.

While some studies support this inverse relationship, evidence is less convincing than for the dilution effect. Richard Ostfeld and Felicia Keesing elaborate on the complexity of these interactions, emphasizing that high diversity of hosts leads to greater pathogen diversity.

Local Focus for Biodiversity Conservation

Given the dilution effect, investing in global biodiversity conservation is beneficial. Dirk Schmeller et al. point out that environmental microbiomes bolster ecosystem stability and function.

A broad commitment to biodiversity conservation is essential, as both host and environmental microbiomes are interconnected, promoting health and stability.

However, James Jones et al. suggest that zoonotic pathogen transmission risk is often a local phenomenon, emphasizing the need for localized ecological focus rather than generalizing trends.

This perspective reinforces the importance of understanding local ecology and interactions to effectively mitigate disease risks.

Final Thoughts

Overall, promoting biodiversity seems to foster healthier lives with lower disease emergence risks while alleviating environmental pressures. A one-size-fits-all approach will not suffice for biodiversity conservation.

To achieve greater biodiversity, we must reflect on our willingness to protect and sustain critical biological hotspots and adopt sustainable lifestyles for the survival of all life forms.

Ultimately, we cannot simultaneously exploit nature and expect to thrive; a harmonious balance between human, animal, and environmental needs is crucial for our collective well-being.