TITLE: Nature’s “perfect balance” is a mystery scientists are trying to decode
https://bigthink.com/series/great-question/sean-b-carroll/
EXCERPTS: “While society’s been humming along and enjoying all these advances in agriculture and medicine, in the last 50 or 60 years, ecologists have learned a lot about how nature works. I’ve codified these into a set of rules called the ‘Serengeti Rules.’”
In the last 60 years, ecologists have discovered that specific animals have an outsized impact on the health of their communities. The functioning of these ecosystems are sometimes entirely dependent upon certain individual species or small groups of species than others, says biologist Sean B. Carroll, who codified the laws of nature into a set of rules called The Serengeti Rules.
I call 'em the Serengeti Rules 'cause you can see them in operation in the magnificent Serengeti. You can see them in operation in all sorts of other places like Lake Erie, but I don't think 'Lake Erie Rules' would've sold as many books.
So, a couple of those rules that are really important is that some animals are more important than others, meaning they have an outsized impact on the communities in which they live. There's sort of this poetry about nature of, you know, every creature has its place and its purpose and everything is equally important.
That's not true.
The functioning of these ecosystems are sometimes much more dependent upon certain individual species or small groups of species than others. That's really important knowledge because if we lose those species, those communities can collapse. And if those communities are somehow compromised, reintroduction or boosting those species can have great knock-on effects on the overall health of the ecosystem.
So for example, in Yellowstone National Park in the United States, it's a pretty famous story of reintroduction of wolves, which had been exterminated from the Lower 48, and the last wolf was killed in Yellowstone in about 1924. So there have been no wolves for 70 years in Yellowstone. And you might say, "So what?" We can get along without these large predators.
Well, that's been shattered by ecological discoveries. These large predators play a really important role. And in the case of Yellowstone, essentially, trees need wolves.
So think about that for a second.
Trees need wolves.
Well, it's by wolves controlling the browsing and grazing of deer and elk. That was absent for 70 years. It was stunting plant and tree life in Yellowstone, and so wolves were reintroduced in 1995. And within a decade, you could see changes in the landscape of Yellowstone. And those changes led to increased abundance of other sorts of creatures.
Similarly, we know that some species have really strong indirect effects on others.
So for example, in the Pacific Northwest, the trees need salmon. Rivers don't have a lot of nutrients. A lot of the nutrients in those rivers comes in from the ocean in the form of salmon bodies. And when those salmon are taken by all sorts of carnivores, and when those carcasses are left on the stream banks, the nutrients from those carcasses fertilize the trees, and we can actually trace those nutrients from the ocean into the trees in the Pacific Northwest.
Who would've thought of such things? As we've learned about all sorts of hidden connections and ecosystems, we're realizing, first of all, why were some of our actions so damaging? But flip side of that coin is why a little bit of action now can be so rewarding, can be so positive, and that these systems, these sort of webs of life, can be restitched just by the introduction of certain key creatures.
This is really important because we are nature's manager now, whether you like it or not, we've taken it over. We're trying to manage nature for the long run so that we have the things that we need and hopefully nature can persist. So we need to keep exploring these interactions, whether they're interactions within the body or they're interactions out there in nature, to manage our future.
TITLE: Reintroducing bison to Kansas tallgrass prairies promotes biodiversity and resilience, study finds
https://www.yahoo.com/news/reintroducing-bison-kansas-tallgrass-prairies-150010728.html
EXCERPTS: Reintroducing bison to tallgrass prairies can double biodiversity of native plants and increase drought resistance, a Kansas State University study found.
The study collected 29 years of data from the Flint Hills.
Native species biodiversity increased between 0.58 and 1.06 species per year, depending on the area with the introduction of bison. Researchers found that introducing cattle increases biodiversity by half, as compared to bison. Dominant grass cover in areas where bison grazed was significantly lower than in ungrazed areas but the grass was not eliminated completely.
The area bison grazed was cleared and gave space for new native plants to thrive. This finding was replicated by cattle, but to a lesser extent. Researchers credit this to differences in their grazing habits.
Bison are year-round grazers, whereas cattle typically only graze during growing seasons. Bison also form grazing lawns, whereas cattle do not. Grazing lawns create areas that lead to a significant decline of dominant grasses, which help create a concentrated area for diverse species to grow.
Researchers gathered data on the species from the 2011 and 2012 droughts, which researchers say were one of the “most extreme drought events that have occurred in the Great Plains since the 1930s Dust Bowl,” and found that the new biodiverse species were resilient during droughts.
“The resilience we found in the bison grasslands is also consistent with the idea that diversity promotes ecological resilience,” said researcher Zac Ratajczak. “And this resilience will only become more important if our climate becomes more extreme.”
Recovery in the bison-grazed areas was rapid, and rebounded to pre-drought levels within two to four years. Researchers found lower resilience in cattle-grazed areas than bison-grazed areas, but it remained higher than ungrazed areas. This is because the dominant grasses in ungrazed areas rely heavily on shallow soil water, and the biodiverse species often rely on deeper soil water. The increase in competition for water between grasses decreases their resilience and ability to rebound.
“Our results suggest that many grasslands in the central Great Plains have substantially lower plant biodiversity than would have occurred before bison were widely wiped out,” Ratajczak said. “Returning or ‘rewilding’ native megafauna could help to restore grassland biodiversity.”
TITLE: Connectivity loss in Pond Networks Threatens Microbial Biodiversity
www.foodmanufacturing.com/home/news/22929123/connectivity-loss-in-pond-networks-threatens-microbial-biodiversity
EXCERPT: In the midst of the ongoing global biodiversity crisis, even the smallest habitats like ponds demand our attention. Fragmentation of these habitats—driven by human activities like urbanization, agriculture, and land-use changes—poses a significant threat to biodiversity. Often overlooked in conservation efforts, ponds serve as vital ecological hotspots, supporting diverse species and sustaining essential ecosystem processes. These waterbodies are home to various microbial communities that, despite their tiny size play an indispensable role in ecosystem functioning, acting as primary producers, decomposers, and links in food webs. While the impacts of habitat fragmentation on large organisms like mammals and birds are well-documented, the effects on microscopic organisms, including bacteria, algae, and other unicellular eukaryotes remain poorly understood.
A recent study carried out by researchers from HUN-REN Centre for Ecological Research in Hungary explored the effects of connectivity loss within pond networks. Using an outdoor experimental setup of artificial ponds (mesocosms), the researchers simulated fragmentation by terminating the movement of water and organisms between habitats in half of the pond networks while maintaining dispersal in the other half. By controlling for factors like habitat size and environmental conditions, and focusing solely on connectivity loss, the study provided an insight into the direct impacts of fragmentation on biodiversity.
“Our findings were particularly striking for unicellular microeukaryotes. Connectivity loss led to significant declines in their diversity at both local and regional levels, highlighting that fragmentation can directly drive biodiversity loss, even under controlled circumstances. Both rare and abundant species were impacted, suggesting that fragmentation represents a widespread and severe threat to microbial biodiversity. In contrast, prokaryotes appeared more resilient, though we observed signs of a potential “extinction debt,” where biodiversity loss may emerge over longer timescales.” – explains Dr. Beáta Szabó, the first author of the study.
Beyond biodiversity, the study also highlighted how connectivity loss disrupts trophic interactions. Zooplankton grazers, which interact closely with microbial communities, experienced reduced biomass in fragmented habitats, further exacerbating the decline in diversity and community evenness of microeukaryotes. These findings highlight the interdependence of organism groups within ecosystems and the cascading impacts that habitat fragmentation can have on biodiversity and ecosystem functioning.
“Our study clearly demonstrates that habitat fragmentation—specifically the loss of connectivity—can have serious and far-reaching consequences for biodiversity. Even when habitat size or environmental conditions remain constant, simply disrupting the dispersal of individuals between habitats can trigger significant declines in microbial diversity. Conservation efforts must not only focus on preventing habitat destruction, particularly in vulnerable ecosystems like pond networks, but also prioritize maintaining and restoring connectivity between habitats to protect the ecosystems and species that rely on them. This is especially crucial for microbes, which, despite their small size, have enormous ecological significance." – summarizes Dr Zsófia Horváth, the senior author of the study and head of the Biodiversity and Metacommunity Ecology Research Group at Institute of Aquatic Ecology, HUN-REN Centre for Ecological Research.
TITLE: How Human Activity Fuels Pandemics: Climate Change and Biodiversity at the Core
https://www.gadgets360.com/science/news/how-human-activity-fuels-pandemics-climate-change-and-biodiversity-at-the-core-7342474
EXCERPT: The rise in pandemics has been attributed to disruptions caused by human activities to the planet's ecosystems. Infectious diseases, which have historically resulted in significant loss of life, are appearing more frequently.
According to a study published by researchers from the University of Adelaide, the disruption of ecosystems is central to the emergence of pandemics. Healthy ecosystems regulate diseases by maintaining natural balances, including predator-prey dynamics and vegetation growth. However, activities such as deforestation, climate change, and biodiversity loss have altered these balances, enabling pathogens to spread more easily. For instance, changes in climate have allowed disease-carrying mosquitoes to expand their range into previously temperate regions.
Reports have indicated that biodiversity loss has created opportunities for pathogens to move from wildlife to humans. The case of vampire bats in South America is often cited, where deforestation and agricultural expansion provided new feeding grounds, leading to the spread of rabies. Similarly, the HIV virus emerged through the hunting of apes for food, eventually spreading globally. These examples underscore the link between human activity and the rise of zoonotic diseases.
It is widely believed that without addressing the root causes, the likelihood of future pandemics remains significant. Efforts to balance human development with ecological preservation have been suggested as key to safeguarding global health.