The climate and biodiversity crises are not two separate things
Review study co-written by FAU paleontologist offers new solutions for combating climate change and biodiversity loss
Reports and ProceedingsAn unprecedented and continuing loss of biodiversity has been sparked by anthropogenic climate change together with the intensive use and destruction of natural ecosystems. However, since the public often views the climate crisis and the biodiversity crisis as two separate catastrophes, an international team of researchers including paleontologist Prof. Dr. Wolfgang Kiessling from Friedrich-Alexander-Universität Erlangen-Nürnberg (FAU) calls for adopting a new perspective: In their review study just released in the journal “Science”, they recommend protecting and restoring at least 30 percent of all land, freshwater and marine zones, establishing a network of interconnected protected areas, and promoting interdisciplinary collaboration between institutions.
Human beings have massively changed the Earth’s climate system by producing greenhouse gas emissions that caused the global mean temperature to rise by more than 1.1 degrees Celsius compared to the preindustrial era. The consequences for our planet are manifold and include among others the rising of global sea levels, frequent extreme weather events, and a loss in biodiversity.
Climate and biodiversity go hand in hand
In their newly published report, “Overcoming the coupled climate and biodiversity crises and their societal impacts”, 18 international researchers highlight the connection between climate crisis and biodiversity loss. Prof. Dr. Wolfgang Kiessling, FAU paleontologist and Chair of Palaeoenvironmental Research at Geozentrum Nordbayern, is one of the co-authors. He explains: “The drastic change in temperatures we experience right now has a great impact on the habitats of animate beings. Since they all have their specific range of tolerance, organisms are forced to shift their territory due to climate change. This comes with different challenges. For instance, mobile species can only migrate to cooler environments for so long until they hit a dead end, for example the coast of a landmass. Sessile organisms like coral reefs on the other hand take several generations to change their habitat. If you look at it long-term, for many of them it may already be too late.”
What makes matters worse is the loss of ecosystems due to agriculture, fishing and industry. The study’s authors estimate that human activities have altered roughly 75 percent of the land surface and 66 percent of the marine waters on our planet. As a result, today approximately 80 percent of the biomass from mammals and 50 percent of plant biomass have been lost, while more species are in danger of extinction than at any time in human history.
Coming full circle, global warming and the destruction of natural habitats not only lead to biodiversity loss, but also reduce the capacity of organisms, soils and sediments to store carbon, which in turn exacerbates the climate crisis.
Adapting now for a good future
In order to address these multiple crises, the researchers propose a combination of emissions reduction, restoration and protection measures, intelligent land-use management, and promoting cross-institutional competencies among political actors. “The key to a good future must be to not only focus on reducing emissions but to make sustainable adaptions to the already existing change in our climate, especially through nature-based solutions”, says Kiessling.
This includes the protection of coastlines by maintaining coral reefs and wetlands; the restoration of at least 30 percent of land, freshwater and marine zones to prevent further biodiversity losses; and the connection of protected areas via migration corridors, hence creating a web of safe habitats around the world for animals. The paper further emphasizes that agriculture and fishing must focus on sustainability: Resource-conserving forms of use and a reliable food supply for the human race have to be ensured, with concepts leading to intensified carbon dioxide uptake and carbon fixation in biomass and soils being prioritized. In addition, sufficient havens must be created for species responsible for making harvests possible, e.g. the insects that pollinate fruit trees.
Unanimous approach necessary
For all of these measures to be successful, countries and institutions across the world need to stand on common ground. As Kiessling puts it: “No matter the issue, be it economic, political or social, we all must look at it with climate change, biodiversity and sustainability in mind, and most importantly: We must understand that what impacts one country will definitely have an effect on others. This is why we need joint strategies and regular exchange between institutions and world leaders.”
The full report is available via the DOI: 10.1126/science.abl4881
JOURNAL
Science
ARTICLE TITLE
Overcoming the coupled climate and biodiversity crises and their societal impacts
ARTICLE PUBLICATION DATE
20-Apr-2023
Neuroptera: Greater insect diversity in the Cretaceous period
An LMU team has studied the biodiversity of larvae from the insect order neuroptera over the past 100 million years.
Human activity is currently driving a loss of natural diversity that some experts describe as the sixth major mass extinction event in the history of the Earth. The decline in insects is particularly alarming: Insects are not just a highly diverse group of creatures in and off themselves, but they are also of tremendous ecological and economic importance.
The extent to which insects are disappearing can only be described as an exceptional situation. To better understand the underlying processes, it is therefore worth delving into past extinction events. Why? Because in the past, too, some groups of insects have gained in significance and diversified while others have been passed by and forced to withdraw into the few remaining niches.
100 million years of larvae diversity
The latter point seems to have been the case for neuroptera, whose modern-day representatives include lacewings and antlions. Researchers have long suspected that the importance of this group of insects has tended to decrease since prehistoric times. Until now, however, there had been no quantitative validation of this hypothesis.
Now, a team working with LMU biologists Professor Carolin Haug and Professor Joachim Haug have published a study in Scientific Reports documenting the diversity of neuroptera from the Cretaceous period to the present day. For the first time, statistical analysis thus backs up scientists’ view of these insects over the course of evolutionary history.
But how do we measure and compare the biological diversity of insects during the process of evolution? At best, we can only paint an incomplete picture of a tiny fraction of the biodiversity that prevailed in past ecosystems, because insect fossils are very rare. And although Jurassic Park may have nurtured expectations to the contrary, DNA for use in relatedness analyses can no longer be extracted from creepie-crawlies encased in amber during the Cretaceous period.
Form and function
Neuroptera are holometabolic insects whose larvae differ considerably in terms of appearance and lifestyle from adults. Whereas many neuroptera pollinate flowers after metamorphosis, their larvae are often fierce predators – as is apparent from their strikingly stylet-like mouthparts. Precisely these larvae mouthparts became the focus of the researchers’ attention. “Unfortunately, the larval phase is often rather neglected in such analyses,” Joachim Haug says. “Yet the larvae in particular often display morphological attributes that we can use as a very informative data basis.”
The basic idea is simple: Different forms are a marker for biodiversity. The more different head shapes and stylets occur in neuroptera larvae, the more ecological functions these creatures assume. It follows that, if an exceptionally large variety of head parts and mouthparts occur in a given geological period, it is reasonable to conclude that these insects occupied many different niches at that time. The principle holds true even if only a few specimens have survived and relatedness remains unclear.
A complex pattern
The researchers measured the heads of more than 1,000 larvae, including all the nearly 300 fossilized neuroptera larvae that are known worldwide and 800 specimens that are still alive today. In this way, they were able to confirm that the diversity of neuroptera larvae has indeed declined in the last 100 million years.
“Although our glance into the past is limited to a small sample size and very specific regions around the globe, we can nevertheless detect greater morphological diversity among neuroptera larvae in the Cretaceous period,” Carolin Haug says. “So, it is probable that actual diversity was in fact substantially greater in the past.” However, the overall picture of neuroptera history is complex: Whereas their diversity as a whole has definitely decreased, some neuroptera lines have diversified and thus gained in importance.
“Our work also showed how much potential lies in the morphological study of insect larvae,” Carolin Haug adds. “Quantitative morphology can reveal changes that cannot be quantitatively recorded within a taxonomic framework.”
JOURNAL
Scientific Reports
ARTICLE TITLE
Quantitative analysis of lacewing larvae over more than 100 million years reveals a complex pattern of loss of morphological diversity
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