During the last century, decreases in biodiversity have been increasingly observed - wikipedia 
A 2017 study published in ''PLOS One'' found that the biomass of insect life in Germany had declined by three-quarters in the last 25 years.
Dave Goulson of Sussex University stated that their study suggested that humans:
appear to be making vast tracts of land inhospitable to most forms of life, and are currently on course for ecological Armageddon. If we lose the insects then everything is going to collapse - theguardian.com
In absolute terms, the planet has lost 52% of its biodiversity since 1970 according to a 2014 study by the World Wildlife Fund.
The Living Planet Report 2014 claims that:
the number of mammals, birds, reptiles, amphibians and fish across the globe is, on average, about half the size it was 40 years ago.
Of that number, 39% accounts for the terrestrial wildlife gone, 39% for the marine wildlife gone and 76% for the freshwater wildlife gone. Biodiversity took the biggest hit in Latin America, plummeting 83 percent.
High-income countries showed a 10% increase in biodiversity, which was canceled out by a loss in low-income countries.
This is despite the fact that high-income countries use five times the ecological resources of low-income countries, which was explained as a result of process whereby wealthy nations are outsourcing resource depletion to poorer nations, which are suffering the greatest ecosystem losses.
As of 2012, studies suggest that 25% of all mammal species could be extinct in 20 years - winnipegfreepress
In 2007, German Federal Environment Minister Sigmar Gabriel cited estimates that up to 30% of all species will be extinct by 2050.
Of these, about one eighth of known plant species are threatened with extinction.arizona.edu Estimates reach as high as 140,000 species per year (based on Species-area curve)
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ucsd.edu
This figure indicates unsustainable (sustainability) ecological practices, because few species emerge each year. Almost all scientists acknowledge that the rate of species loss is greater now than at any time in human history, with extinctions occurring at rates hundreds of times higher than background extinction rates.