The Living Planet Index (LPI) is a measure of biodiversity that is often misinterpreted. In my accompanying article on the Living Planet Index, I describe these misinterpretations in detail, and what it actually tells us about the state of global biodiversity.
In brief, the LPI measures the average change in the size of studied animal populations. It does not tell us the total change in animal populations; the share of populations that have been lost; or anything about extinctions.
But these results vary a lot from region to region.
In the chart we see the LPI given by region. This is measured relative to 1970, which is assigned a value of one.
Latin America and the Caribbean
Latin America and the Caribbean have seen the most severe decline of any region. It experienced an average decline of 94% across its studied populations. When we think about the changes in some of the leading drivers of biodiversity loss, we should not be surprised that Latin America has been badly affected.
In recent decades it has experienced intense deforestation and expansion of agricultural land: the primary driver of habitat loss. It is also a biodiversity hotspot, being home to many endemic (unique) tropical species. These species are often highly specialized, and don’t adapt well to changes in local conditions.
The LPI highlights the conversion of grasslands, forests, wetlands and the harvesting of species for hunting and poaching as the main contributors to this decline. It was most severe for fish, reptiles and amphibians.
The trend for North America is one of two halves. Since 1970, it has experienced an average decline of 20%. But, most of this occurred before the year 2000. After a steady decline through the 1970s, 80s and 90s, the trend seems to have stabilized from the turn of the millennium. In fact, the average trend might be slightly increasing.
Europe and Central Asia
Europe has seen the smallest decline of all of the continents. An average decline of 24% since 1970. This paints a less severe picture for biodiversity in Europe and Central Asia, and is attributed in part to successful conservation efforts. For example, most countries in Europe are afforesting and restoring wild ecosystems.
It’s also true that most of the continent’s transformation – the expansion of agriculture, deforestation and destruction of habitats – occurred well before 1970. It is a history that goes back centuries. In other words, it’s biodiversity was already in a very depleted state. We’d expect that any declines in the region would be less severe.
Africa is still rich in biodiversity. It’s the only continent with a significant number of large mammals left. Unfortunately, it has seen a dramatic decline in recent decades. An average decline of two-thirds (66%) since 1970.
Like Latin America, the main drivers of this are habitat loss for expanding agriculture, and the overexploitation of animals for hunting, poaching and wildlife trade. Looking at initial trends in the continent’s subregions, it looks like the decline has been most severe in West, Central and East Africa. Populations have been more stable in the North and South.
The Asia-Pacific spans a wide range of countries and habitats. It includes large terrestrial landscapes, but also many small island states. This means it’s home to a large number of endemic species and unique ecosystems.
Since 1970, it has experienced an average decline of 45%. But there are initial signs that this is changing. We’ve seen a positive trend since 2010. This has been seen clearly in population trends for several species of reptiles and amphibians.
There is one particular environment that has experienced an incredibly severe decline: the world’s freshwaters.
Almost one-third of freshwater species are threatened with extinction.2 Freshwater species are at higher risk of extinction compared to terrestrial species. This bleak reality is also reflected in trends within the LPI.
The LPI covers 3,741 freshwater populations across 944 species. Not a small, limited sample. Since 1970, the average decline has been 84%. That’s a 4% decline every year. Most of this decline has come from reptiles, amphibians, and fishes. Particularly across Latin America and the Caribbean.
Overfishing and overharvesting of freshwater amphibians and reptiles – which are often traded in markets for their body parts, or for medicinal uses – is one of the biggest threats to these species.
Freshwaters are also polluted by many different types of waste: agricultural waste from manure and fertilizers, industrial discharge, and domestic waste. This can very quickly tip the balance of species within freshwaters. The diversion of rivers and use of dams can also alter the habitats for these species.
Conservation efforts in these environments are also more difficult because it usually requires input from multiple sectors. The allocation of responsibility for water is not as straightforward as for land. Just like terrestrial mammals, it’s the megafauna (the largest species) that are at greatest risk.
Freshwater megafauna are species that grow to more than 30 kilograms and include animals such as Mekong giant catfish, river dolphins, otters, beavers and hippos. All of these are targeted by humans. What makes them especially vulnerable is that they reproduce at much slower rates and have less offspring.3 This makes it more difficult for them to restore their populations that have been depleted.