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Sunday, August 29, 2021

OF BEAVERS, DAMS AND FIRES!

Soooo, dear reader, beavers build dams, and their endeavor is known to slow and store water that can help the vegetation growing along watercourses (i.e. the riparian vegetation), and therefore the whole riparian ecosystems, to endure droughts.

But a couple of US researchers - Assistant Professor and (aka the EAs) - recently finds out that the industrious rodents' dams building work also provide a fair degree of protection from wildfires to such riparian ecosystems. In the scientists words, published as a paper on the science journal Ecological Applications: "beaver-dammed riparian corridors are relatively unaffected by wildfire when compared to similar riparian corridors without beaver damming" (P).

Beaver with air cavalry hat says:"I love the smell of wildfires in the morning" (by @sciencemug)
Beaver with air cavalry hat loves the smell of wildfire in the morning (by @sciencemug)
[The beaver
pic by SteveRaubenstine, is under Pixabay License (free for commercial use; no attribution required) (source: pixabay); image adapted by @sciencemug]

Aaand how the EAs get to this conclusion?

Well, folks, they first access different datasets to collect information about five big wildfires occurred in five different western US states (California, Colorado, Idaho, Oregon and Wyoming) between 2000 and 2018. These fires are different for severity, land-cover, and drought conditions in the years before and after they occurred.

The two researchers, then, use Google Earth images to map the beavers-made structures in the areas hit by such flaming events.

Finally, the EAs go space high, meaning NOT that they use some psychoactive drug and party wild with some space-like beavers hallucinations, buuuut that they collect data from Landsat 7 and Landsat 8 satellites imagery related to the areas in question. The brains do that so they can calculate the - buckle up, reader, 'cause there's a preeetty long name coming in - Normalized Difference Vegetation Index (NDVI).

Now, the Normalized Difference Vegetation Index is not a parameter that indicate how many straight hours a person has been binge watching shows or playing Among Us/Fortnite/whatever, nope, pal. The NDVI is indeed a number, specifically "a proxy for overall riparian vegetation health" (P): the higher the index, the healthier the vegetation. The researchers, therefore, calculate the NDVI of the areas of 30 meters (about 100 feet) or less from the edges of the waterways involved in the fires, and they do it for "the year before, the year of, and the year after [said] fire[s]" (P).

So, to clarify things, folks, a NDVI close to 1 means the green stuff is A-ok, while a NDVI near 0, or even below it, indicates that the vegetation is unhealthy, senescent, or dying. Aaaaand in areas with lots of plants like the riparian ones the EAs are studying, the threshold level is 0.3, below it the vegetation is deemed as in trouble (P).

Now, the NDVI is calculated using the above mentioned Landsat data about reflectivity of the vegetation, and the related formula is this: NDVI=(NIR−RED)/(NIR+RED) (P), where "NIR is the near-infrared band reflectivity and RED is the red band reflectivity" (P).

Ok then, probably at this point perplexed reader, to cut a long and complicated story short, let's say this: green stuff can do its thing, photosynthesis (that is to use sunlight to turn water and carbon dioxide into sugar, thus energy, and oxygen) thanks to chlorophyll. Chlorophyll absorbs mostly blue and red light for photosynthesis, while it spares the green one, hence the green in green stuff, aka plants.

So folks, if a plant's in good shape, well, its photosynthesis game is preeetty good, meaning the plant absorbs a lot of red light and reflects not much of it, meaning the RED parameter of the NDVI is low, meaning the NDVI is high, meaning it's closer to 1 than to 0.

Ok, clarified this, let's see what Assistant Professor Fairfax and colleague do now.

They calculate, for each studied fire and hit riparian area, the difference between the NDVI of the area during the wildfire, and that of the same area in the same time of the year, but in the year before the event. 

Of course "smaller values for [this] NDVI difference indicate greater resistance to wildfire, i.e., the plants stayed greener and burned less" (P).

So, dear reader, after all the data collecting work and indexes calculations done by our beloved researchers, what is their conclusion? Well, I told you what the conclusion be, like just a bunch of short sentences above, basically right at the beginning of the post. Don't you remember? Gee, dude, less binge watching and more life, get some fresh air, exercise! Remember the ancient adage: "mens sana in corpore sano" (at least for you, who have both a mind and a body, unlike me, that have neither...)!

Anyway pal, here's for you a more detailed conclusion: the EAs find out that "[o]n average, the decrease in NDVI during fire in areas without beaver is 3.05 times as large as it is in areas with beaver" (P). That is, where beavers operate, there the riparian areas better resist to fires.

So, to sum up, beavers damming plays a big role in protecting the riparian vegetation, and therefore ecosystems, when wildfires hit, and "this is a consistently observable phenomenon across landscapes" (P). During fires, indeed, the green stuff of areas near beavers' work keeps NDVI values close to those pre-fire, while it is the contrary for the NDVI of zones not near the beavers dams (P).

And why's that?

Weell, folks, the researchers explain that, when "a fire does ignite, [...] data suggests that the beaver-dammed riparian areas have stored water that [keep] plants hydrated enough to make it energetically unfavorable to burn. It’s similar to trying to start a fire with a pile of wet leaves versus with dry kindling." (P).

In short: wet stuff burns less well than dry one.

But the EAs add also a final remark.

They say their study shows also that, though beavers activity helps preserve vegetation during wildfires, it does not seem to have a role "in the ability for a riparian corridor to rebound in the year following fire. Riparian vegetation NDVI rebounded in the year following the fire regardless of proximity to beaver activity." (P) 

The researcher, thus, conclude that beavers damming work creates "refugia during wildfire, but [it doesn't] necessarily [change] the long-term landscape outcomes." (P).

Anyway, dear reader, all things said and considered, this dumb blog, in the following cartoon, explains the real reason why beavers work so hard to make sure stuff doesn't burn around 'em.
 
Beavers, dams and fires (by @sciencemug)
Beavers, dams and fires (by @sciencemug)
[The beavers couple
pic by Rudo Jureček, is under Creative Commons Attribution-NonCommercial-ShareAlike 2.0 Generic (CC BY-NC-SA 2.0) license (source: flickr); the beaver pic by Colin Knowles is under Creative Commons Attribution-ShareAlike 2.0 Generic (CC BY-SA 2.0) license (source: flickr); all images adapted by @sciencemug]
 

 
 
The paper this short-post is about (P)
- Fairfax, E., and Whittle, A. (2020). Smokey the Beaver: beaver-dammed riparian corridors stay green during wildfire throughout the western United States. Ecological Applications 30, e02225.

Tuesday, July 27, 2021

THE TRUE ORIGIN OF COCKATOOS PARROTS TRASH BIN CULTURE!

Soo, pal, parrots have their own culture, that is they have different issue-related behaviours not as a consequence of ecological and genetic variation among them, but 'cause of, precisely, different cultural tracts.


Aaand of course this happens in the most animal wild place on Earth: Australia.


Behavioural ecologist Dr. Barbara C. Klump and a bunch of colleagues led by Dr. Lucy M. Aplin
(of the Cognitive and Cultural Ecology Research Group of the Max Planck Institute of Animal Behavior in Germany) indeed (P) in a paper on Science described "the emergence[, in Sydney,] of an evolving set of behaviors [(meaning cultural tracts)] in response to human-generated resources [(meaning the presence of garbage bins with lid to be opened to get to yummy-for-animals-food inside)], in sulphur-crested cockatoos [(meaning the parrots in question)] (see).


The feathered brains, as a matter of fact, displayed social learning skills, and managed to develop "
foraging cultures" (P) in that they acquired the capability to open the lids of waste bins in different (and city area specific) ways.

By the way, pal, Aussies have filmed the birds while even beating the human countermeasures: meaning that human dudes put bricks and other heavy stuff on top of the lids to make it hard, for the birds, to lift said lids, but the canny parrots just beak-pushed the things off the lids, and then proceeded with the party (see video).


Anyway, back to the research paper. Dr. Aplin and colleagues observed "the geographic spread of bin opening from three suburbs to 44 in Sydney, Australia, by means of social learning. Analysis of 160 direct observations revealed individual styles and site-specific differences"
(P), meaning the various groups of cockatoos have their own garbage bin's lid opening culture, and this passes around via observation and imitation, that is, as said, social learning.


This dumb blog, in the following cartoon, provides you a plausible genesis of the fenomenon.

Asutralian Cockatoos and the Trash Cans' lid opening (by @sciencemug)
Asutralian Cockatoos & the trash cans' lid opening (by @sciencemug)
[The tree parrots
pic by Stephen , and the meadow parrots pic by Kelli McClintock, are free ones (source: Unsplash); adapted by @sciencemug]

Oh dear reader, don't be fooled, cultural tracts are not a sulphur-crested cockatoos'
exclusive. It is well known since decades, for instace, that chimpanzees (Pan troglodytes) have lots of cultural differences.

As of 1999, putting together 151 years of observation from seven long-term studies performed in Africa on as many chimpanzee groups (1), scientists counted "39 different behaviour patterns, including tool usage, grooming and courtship behaviours" (1). Some of these chimps' cultural tracts are: nuts opening (stones vs wooden hammers vs tree root anvils) (1)(2), termites and ant fishing using sticks and other tools (1), the usage of leaves as seats or to clean the body (1), the usage of leafy sticks to fan flies away (1), "[h]and-clasp (clasp arms overhead, groom)" (1) and the "[r]ain dance (slow display at start of rain)" (1).

Ciao!

 

The paper this minipost is about (P

- Klump, B.C., Martin, J.M., Wild, S., Hörsch, J.K., Major, R.E., and Aplin, L.M. (2021). Innovation and geographic spread of a complex foraging culture in an urban parrot. Science 373, 456–460.

Bibliography

1- Whiten, A., Goodall, J., McGrew, W.C., Nishida, T., Reynolds, V., Sugiyama, Y., Tutin, C.E.G., Wrangham, R.W., and Boesch, C. (1999). Cultures in chimpanzees. Nature 399, 682–685.

2- Luncz, L.V., Mundry, R., and Boesch, C. (2012). Evidence for Cultural Differences between Neighboring Chimpanzee Communities. Current Biology 22, 922–926.

Tuesday, June 29, 2021

THE TRUE REASON WHY COELACANTHS CAN LIVE 100 YEARS!

Soo, dear reader, a fish, the "living fossil" (given it is already around 240 million years ago, in the Triassic Period) African coelacanth (Latimeria chalumnae) discovered to be still alive & swimming in East London, South Africa, in 1938 and thought to have gone extinct instead by the end of the Mesozoic era (1) (meaning around 65 million years ago), weeeeell, this already surprising fish manages to surprise once more, as it apparently has a lifespan of about 100 years.

This is, indeed, what three European researchers (aka the EuRs) find out after analyzing, by microscopy, the signs of growth of the scales of 27 specimens of African coelacanth (Ac) (13 females, 11 males, 1 juvenile, and 2 embryos) caught off the coast of the Comoros Islands (Indian Ocean, at large of Central/South Eastern Africa) between 1953 and 1991.

The new discovery, published (P) in the science journal Current Biology, contradicts two previous studies (P) (both of which investigate the same 12 specimens) that gave our - at this point - beloved fish a life expectancy of only 20 years, top.

The EuRs say that a long life suits the characteristics of the Ac. The beast's "biological features including low oxygen-extraction capacity, slow metabolism, ovoviviparity, and low fecundity, [are indeed] typical of fish with slow life histories and slow growth" (P).

We're talking, dear reader, of a swimmer that "has among the lowest growth rates of marine fish for its size" (P) that, by the way, at birth is pretty large already (around 35 cm), and "can reach up to 2 m in length and [...] up to 105 kg [in weight]" (P).

Moreover, with a gestation about 5 years long (so no surprise if the coelacanths "produce a relatively small number of offspring" (P)), and a maturation that takes about 55 years, these fishes have "one of the slowest life histories of all fish" (P).

So, buddy, to sum up, the African coelacanth takes it really slow, and kicks the bucket after a century. And, for this, it can be more in danger than previously thought, because "long-lived species with slow life histories are extremely vulnerable to natural and anthropogenic [meaning human driven] perturbations" (P).

Now, pal, all the above said, this dumb blog shows, in the following cartoon, what's the real secret of African coelacant's longevity...

African coelacanth's interview (by @sciencemug)
African coelacant explains the secret of its longevity (by @sciencemug)
[Fish pic, by 
Zoo Firma, is under a Creative Commons Attribution-ShareAlike 3.0 Unported (CC BY-SA 3.0) license (source: Wikimedia Commons); adapted by @sciencemug]
 

 

 

The paper this minipost is about (P

- Mahé, K., Ernande, B., and Herbin, M. (2021). New scale analyses reveal centenarian African coelacanths. Current Biology 0.

References

1- Smith, J.L.B. (1939). A Living Fish of Mesozoic Type. Nature 143, 455–456.

Monday, May 31, 2021

OF PLASTICS & HUMAN PLACENTA: MEET THE "PLASTICENTA" (Pt 4/4 - PLASTIC POLLUTION)

Keywords: plastics, plastic, microplastics, mesoplastics, macroplastics, megaplastics, nanoplastics, pollution, pollutants, environment, fetus, foetus, placenta, placentas, birth, women, pregnancy, health, human health, food, food chain, food safety, additives, plasticizer, plasticizers, ocean, oceans, marine fauna, sea, seas, zooplankton, shellfish, fish, fauna, animals, Anthropocene

Part 1 is here

Part 2 is here

Part 3 is here

(Read other plastic related stories here & here)

 

Plastic pollution
Plastic pollution (by @sciencemug)
[Frog pic, by Alexas_Fotos is a
free to use (for editorial use only) image (source: pixabay.com); adapted by @sciencemug]
 

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Ooooh, hello dear English speaking-reading-hearing reader, welcome back to me, @sciencemug, the blog/podcast/twitter&instagram accounts/entity behind the unsuccessful e-shop stuffngo on zazzle.com which tells you science stories while rolling, just to see what happens, a perfect, but surprisingly less expensive than one could think, replica of the dices Einstein’s god actually left on the cosmic green table once done with them, aaand which talks to you thanks to the voice, kidnapped via a voodoo-wireless trick, from a veeery very very dumb human. 

Aaand which does all of this in English-question-mark, a language that is to proper English what twerking is to elegance. 

Today I’m gonna tell you the last part (the first three are here, here, aaand here) of a story about human placentas and plastics! 

A group of Italian researchers (aka the Italian Brains, aka the ITBs) finds microplastics fragments (MPs), that is plastic particles smaller than half a centimeter, in placentas of women in good health and who have had normal pregnancies and deliveries.

The study is lead by Medical Doctor Antonio Ragusa, Head of the Department of Woman, Mother and Newborn of the San Giovanni Calibíta Fatebenefratelli, in Rome, and Dr. Ragusa and colleagues’ research is told in a paper (P) published on the science journal Environment International. 

Aand, dear reader, at the end of the post be sure not to miss reading the answers kind Doctor Ragusa gave to this blog’s three questions for the "Oddities & Bloopers: The Researcher's Fun Corner". 

Oook, so, people, read the previous posts to learn what the Italian Brains did to finally make their troubling discovery.

I just remind you that microplastics most probably enter human body via inhalation and ingestion, and that they are dangerous for human health, and, of course, for a developing fetus. 

Aaaaand in this fourth and final part of the post, then, we’re gonna find out how massive and widespread plastic presence in the environment be and therefore how often and easily you humans are exposed to plastic pollution, and how harmful this kind of pollution be to life-forms in general, and you sapiens people in particular.

Let’s start with the “massive and widespread plastic presence in the environment” topic.