Biodiversity provides essential resources like clean air, clean water, food and medicines. Diverse ecosystems also offer benefits such as climate regulation, flood control and pollination, while supporting culture, recreation and spiritual enrichment.
Biodiversity. It’s been poetically described as the magnificent tapestry of life that adorns our planet, a vibrant and intricate mosaic woven from countless threads of existence. It encompasses the extraordinary variety of life on Earth, from the smallest microbes hidden in the soil to the towering redwood trees that touch the sky, and from the tiniest insects to the largest whales that travel the oceans.
Now, what if all this incredible biodiversity on Earth followed a surprisingly simple pattern? New research shows that in every region, species tend to cluster in small hot spots and then gradually thin out. This universal rule applies across drastically different organisms and habitats from dragonflies to trees, octopuses to oceans. Scientists believe that “environmental filtering” shapes this global distribution, providing new tools to predict how life responds to biodiversity threats—such as us.
Humans are having a highly detrimental impact on biodiversity worldwide. Not only is the number of species declining, but the composition of animal and plant communities is also changing. However, there is something we can do about it: prioritizing the establishment and effective management of large, interconnected protected areas with high ecological integrity can help achieve the biodiversity that is crucial for human survival and well-being.
A new study reveals a predictable global rule: most species originate from biodiversity hot spots. Today, Conservation International, an organization that protects nature around the world, recognizes 36 biodiversity hot spots. One of them is the New Zealand archipelago.
The one, global rule that predicts where life thrives—and where it fails
After studying bioregions across the world, researchers from England’s University of Reading and Sweden’s Umea University believe they have now identified a simple rule that governs how life is organized on Earth. By examining species from very different life-forms—amphibians, birds, dragonflies, mammals, marine rays, reptiles and trees—they found the same pattern everywhere.
The rule is simple: in every region on Earth, most species cluster together in small “hot spot areas,” then gradually spread outward with fewer and fewer species able to survive farther away from these hot spots.
Given the vast differences in life strategies—some species crawl, others fly, swim or remain rooted—and the contrasting environmental and historical backgrounds of each bioregion, the researchers initially thought that species distribution would vary widely across them. What they found instead was that in every bioregion, there is always a core area where most species live. These cores provide optimal conditions for species diversification and survival; and from them, biodiversity radiates outward. However, only a subset of species manages to persist.
The forests of East Australia are considered another biodiversity hot spot. Reptile endemism here is 27%. One endemic reptile, the rain-forest-dwelling Boyd’s forest dragon, is unusual in that its body temperature is generally within one degree of the air temperature.
The pattern points to a general process known as “environmental filtering,” long considered a key theoretical principle in ecology for explaining species distribution on Earth. Until now, actual, global evidence was scarce. This study, which was published in the journal Nature Ecology and Evolution in June 2025, provides broad confirmation across multiple branches of life and at a planetary scale. It doesn’t matter whether the limiting factor is cold, drought, heat or salinity, conclude the scientists. The result is always the same: only species able to tolerate local conditions establish and persist, creating a predictable distribution of life on Earth.
This rule helps explain why species are spread the way they are across the planet, and the pattern highlights the disproportionate ecological role that these small areas play in sustaining the biodiversity of entire bioregions. Safeguarding these core zones is, therefore, essential. And the existence of a universal organizing mechanism has profound implications for our understanding of life on Earth: it may be, to some extent, predictable. Such predictable patterns can help scientists trace how life has diversified through time and offer valuable insights into how ecosystems might react to global environmental changes.
The devastating human impact on biodiversity
But today, that spreading biological diversity is under threat. Increasingly, animal and plant species are disappearing worldwide, and humans are responsible. To date, there has been no synthesis of the extent of human intervention in nature and whether the effects can be found everywhere in the world and in all groups of organisms. This is because most of the studies previously conducted have only looked at individual aspects. They either examined changes in species diversity over time or were limited to a single location or to a specific human impact. Based on these studies, it is difficult to make any general statements about the collective effects of humans on biodiversity.
Human activities significantly impact freshwater habitats, leading to the degradation of vital ecosystems and biodiversity loss. In Oregon, the Klamath River dam removal project—the largest in history—was completed in 2024, restoring the river’s natural flow and habitat, particularly for salmon.
To fill this research gap, a team from the Swiss Federal Institute of Aquatic Science and Technology and the University of Zurich has conducted an unprecedented synthesis study, one of the largest ever conducted on this topic. The researchers compiled data from approximately 2,100 studies that compared biodiversity at almost 50,000 sites affected by humans with the same number of reference sites that were not affected. The studies covered freshwater, marine and terrestrial habitats around the world and all groups of organisms, including birds, fish, fungi, invertebrates, mammals, microbes and plants.
The findings of this synthesis study, which were published in the journal Nature in March 2025, are unequivocal and leave no doubt as to the devastating influence that humans are having on biodiversity worldwide. After analyzing the effects of the five main human impacts on biodiversity—climate change; direct exploitation, such as fishing or hunting; habitat changes; invasive species; and pollution—the results showed that all five factors have great consequences on biodiversity all over the planet, in all groups of organisms and in all ecosystems.
On average, the number of species at sites affected by humans was almost 20% lower than at unaffected sites. Particularly severe species losses across all biogeographic regions were found in vertebrates such as amphibians, mammals and reptiles. Their populations tend to be much smaller than those of invertebrates, increasing the probability of extinction.
Humans are having a devastating impact on animal biodiversity worldwide. For tigers, habitat loss through deforestation for agriculture, infrastructure development—including roads and settlements—and timber and poaching for their body parts has significantly reduced the animal’s numbers.
However, the repercussions we cause go far beyond the loss of species. Human pressure is also changing the composition of species communities, a second key aspect of biodiversity. In high mountain regions, for example, specialized plants are at risk of being displaced by species from lower altitudes as the climate warms. In some circumstances, the number of species at a particular site may remain the same; nevertheless, biodiversity and its ecosystem functions will be affected if, for example, a type of plant disappears that has particularly good root systems to protect the soil from erosion. The greatest shifts in the species communities are found among tiny microbes and fungi, perhaps because these organisms have short life cycles and high dispersion rates and, therefore, respond more quickly.
It’s not surprising that environmental pollution and habitat changes have a particularly negative impact on the number and the composition of species communities. Habitat changes are often very drastic, such as when we cut down a forest or level a meadow. Pollution, whether accidental, as in the case of an oil tanker spill, or deliberate, as in the case of spraying pesticides, introduces new substances into a habitat that destroy or weaken the organisms living there. This does not mean, however, that climate change is less problematic for biodiversity in comparison. It’s likely that the full extent of its damage cannot yet be verified.
The third key aspect of biodiversity that the research team investigated was homogeneity, or how similar species communities are at different sites. For example, large-scale, intensive agriculture tends to make landscapes more homogeneous and the species communities they contain more similar. The scientists showed that homogeneity effects were mixed, with some studies showing a very strong tendency towards homogenization and others displaying a tendency for species communities to become more diverse, especially at the local level. However, the latter is probably not a good sign. Increasing dissimilarities could also be a temporary effect in severely impaired habitats.
The habitat changes that humans create can have a particularly negative impact on the composition of animal and plant communities. They’re often very drastic, such as when we cut down a forest or level a meadow.
According to the authors, their work demonstrates, on the one hand, that changes in biodiversity should not be based solely on changes in the number of species. On the other hand, the findings are alarming due to their distinctness and global validity. The scientists hope the results may serve as benchmarks for future biodiversity research and conservation efforts since they provide clear indications of which human influences are leaving the greatest marks on biodiversity and point to the goals that need to be set if such trends are to be reversed.
The conservation of Nature’s Strongholds could halt biodiversity loss
We can stem biodiversity loss, argue scientists from the Wildlife Conservation Society and colleagues in an essay published in the open-access journal PLOS Biology in May 2024: to achieve global biodiversity targets, we must prioritize (1) large, (2) interconnected conserved and protected areas with (3) high ecological integrity (4) that are effectively managed and equitably governed.
The essay authors emphasize the importance of conserving landscapes at scales large enough to encompass functioning ecosystems and the biodiversity they contain. In many cases, this will require interconnected groups of protected areas that are managed together. Effective governance means that the diversity of rights holders and stakeholders are recognized, and that the costs and benefits are shared equitably between them. The authors state that protected and conservation areas that meet all four criteria—which they call “Nature’s Strongholds”—will be disproportionately important for biodiversity conservation on a global scale. Examples of some Nature’s Strongholds are the biodiverse, tropical forest regions of the Amazon and Central Africa.
With rich biodiversity, the tropical forests of the Amazon are an example of a Nature’s Stronghold. Amazon rain forests support an estimated 10% of the world’s known species, including jaguars, unique tree frogs and macaws, such as these.
The perception of biodiversity often matches the reality
We know that protecting biodiversity is important for our health. But we’re now learning that even just how we perceive the natural world has health implications, too.
In a new study that was led by researchers at Germany’s Friedrich Schiller University Jena, the German Center for Integrative Biodiversity Research the Helmholtz Center for Environmental Research and that was published in the British Ecological Society journal People and Nature in July 2025, participants with no ecological training were asked to sort audio recordings and images of forests based on perceived biodiversity.
In each of the two sorting studies, 48 participants were presented with 16 audio recordings or 57 photographs of forest patches throughout Belgium, Germany and Poland with varying levels of biodiversity. The actual biodiversity of the forests in the photographs was assessed using a combination of four, commonly used, forest diversity indicators: forest structural diversity, tree species richness, understory abundance and understory structural diversity. Actual biodiversity in the audio files was measured via bird species richness.
When study participants looked at images of forest patches in Belgium, Germany or Poland, their intuitive perception of biodiversity was remarkably accurate, closely aligning with scientific measures. Perceived biodiversity is linked to our mental health and well-being as much as measured biodiversity.
To understand what indicators of biodiversity people were perceiving, the researchers also asked the study participants to sort the audio recordings and images according to any criteria that stood out to them. Visually, people noticed color, light conditions or vegetation density. Acoustically, people noticed birdsong characteristics, the emotions that the audio recordings evoked or volume.
Astonishingly, the researchers found that the biodiversity levels that participants perceived from the materials closely matched the actual biodiversity of the forests.
The scientists write that not only are we experiencing a sixth mass extinction but also an extinction of biodiverse experiences. In addition to conserving and restoring diverse forests characterized by an array of tree species, they recommend providing habitats for different vocalizing birds. They state that this will have the dual benefit of meeting conservation goals while also increasing people’s experience of biodiversity and, therefore, likely increasing mental well-being.
Evidence from the fields of biology and psychology suggests that we have an innate tendency to connect with nature, a concept known as “biophilia.” Popularized by E. O. Wilson, it argues that this connection is rooted in our evolutionary history, as our ancestors relied on natural environments for survival.
The innate longing for biodiversity
According to World Wildlife Fund, biodiversity is “all the different kinds of life you’ll find in one area—the variety of animals, plants, fungi and even microorganisms like bacteria that make up our natural world. Each of these species and organisms work together in ecosystems, like an intricate web, to maintain balance and support life.” The American Museum of Natural History states that biodiversity is “the variety of life on Earth at all its levels, from genes to ecosystems, and can encompass the evolutionary, ecological and cultural processes that sustain life.” United Nations Climate Change says biodiversity means “all life on Earth from microbes to rain forests, and how that life interacts with each other. Essentially, it is the fabric that holds the planet—and every life on it—together.”
Of all the definitions of biodiversity that I’ve ever heard, though, I like biologist E. O. Wilson’s the best: biodiversity is “the very stuff of life.” I think the fact that we humans can perceive levels of biodiversity by just looking at a picture or hearing an audio recording speaks to a long-ago ability that must still sleep within us, waiting to be fully awakened.
Here’s to finding your true places and natural habitats,
Candy
The post Biodiversity: Where It Thrives, When It Doesn’t and How We Innately Know It first appeared on Good Nature Travel Blog.