How sharks and rays evolve


This 21 May 2020 video says about itself:

Sharks and Rays by Annie Crawley

Sharks & Rays takes you on a journey to discover the wonders of sharks and rays from around the world. Join underwater photographer, filmmaker and ocean explorer, Annie Crawley to learn all about these amazing creatures. You learn the biology with complex information in easy to understand language.

Exclusive footage will have you diving with schooling hammerhead sharks, observing manta rays feeding, nurse sharks entering a state of tonic immobility, plus you will experience the first Shark Sanctuary in the world while diving in the blue waters of Palau. Whale sharks, hammerheads, great white sharks, electric rays, manta rays, reef sharks, mako sharks, dozens of species of sharks and rays from around our world’s ocean are explored in this program.

From Flinders University in Australia:

Ecosystem diversity drives the origin of new shark and ray species

May 19, 2020

Summary: Biologists how different oceanographic conditions in the Gulf of California and the Baja California Peninsula influenced formation of new species of sharks and rays.

What drives the evolution of new species of sharks and rays? Traditionally, scientists thought it required species to be separated by geographic or spatial barriers, however, a new study of elasmobranchs (the group of sharks and rays) has challenged this expectation — and found evolution is happening faster than many think.

Flinders University evolutionary biologists Dr Jonathan Sandoval-Castillo and Professor Luciano Beheregaray tested how different oceanographic conditions in the Gulf of California and the Baja California Peninsula (Mexico) influenced the formation of new species of guitarfish (genus Pseudobatos).

The team discovered four types, or ‘young species’, of guitarfish that have similar external appearance but are genetically different.

Each type of guitarfish appears to have adapted to one of the four separate regions of the Gulf of California. This promotes environmental tolerances which result in those guitarfish having improved odds for survival and reproduction in the region where they were born.

“We have shown that these four guitarfish species evolved quite quickly from the same common ancestor,” says Dr Jonathan Sandoval-Castillo.

“The process where several new species originate from one ancestor in a relatively short period of time is called adaptive radiation, and this is the first report of such a process in sharks and rays. Our results help changing the false popular belief that sharks and rays do not evolve, or only evolve very slowly,” says Prof Luciano Beheregaray.

These findings also have important implications for the management of exploited elasmobranch species, such as guitarfish in the Gulf of California which represents an important fishery for Mexico.

If these young species adapt and evolve to their local habitat conditions, they cannot be replaced by migrants from other habitats.

“If such species are incorrectly managed as a single stock, it can result in the over-exploitation and possibly extinction of the entire species.”

Common whitethroat, mallards and gadwalls


Mallards and gadwall, 20 May 2020

After my earlier blog post, still 20 May 2020 in the sand dunes nature reserve. We walked away from the lake, just south of Egmond aan Zee village. Just to the south of that lake, in the next lake, were these three mallards dabbling, and a gadwall duck swimming behind them.

Further away, a little grebe swimming.

Common whitethroat, 20 May 2020

On a bush above the lake, this common whitethroat singing.

Common whitethroat, on 20 May 2020

An oystercatcher flying.

Mallards, 20 May 2020

Meanwhile, the mallards were still dabbling.

Gadwall, 20 May 2020

The gadwalls had moved to another part of the lake.

Gadwall, on 20 May 2020

As we walked back, a brimstone butterfly.

Will tapirs save the Brazilian Amazon?


This video says about itself:

SAVING AMAZON TAPIRS

The story of our Amazon journey in June 2019 and our plans for the establishment of the LTCI Amazon Tapir Program in 2020!

Filmed and produced by Laurie Hedges.

By Gloria Dickie, May 12, 2020 at 8:00 am:

Tapirs may be key to reviving the Amazon. All they need to do is poop

A Brazilian ecologist is determined to understand the role of tapir dung in forest restoration

Beneath the viridescent understory of the Brazilian Amazon, ecologist Lucas Paolucci has been honing his skills for hunting tapir dung. In this region’s degraded rain forests, he sees the piglike mammal’s enormous piles of poop as a treasure.

Chock full of seeds, the dung from trunk-nosed lowland tapirs (Tapirus terrestris) may be key in regenerating forests that have been hit by intensive logging and slash-and-burn agriculture, says Paolucci, of the Amazon Environmental Research Institute in Brazil.

“Tapirs in Brazil are known as the gardeners of the forests,” he says. Feasting on the fruit of more than 300 plant species, the animals travel through the forest underbrush with their bellies full of seeds. That includes seeds from large, carbon-storing trees like mess apple trees (Bellucia grossularioides) that can’t pass through smaller animals. So the lowland tapir, South America’s largest mammal, is one of the key agents dispersing seeds throughout the Amazon.

Rooting through poop piles in Mato Grosso, a state in west-central Brazil, wasn’t how Paolucci began his career; he studied ants in Brazil’s coastal Atlantic Forest. Later, he began to wonder how forest fires in the Amazon might affect the rain forest’s insect communities. And then, he became intrigued by the monstrous dung piles — each pile “bigger than my head”, he says.

In 2016, Paolucci joined other researchers studying the role of these magnanimous defecators in restoring disturbed forests. The team conducted an experiment in eastern Mato Grosso, where two forest plots had been control burned to varying degrees from 2004 to 2010. One plot was burned every year, and the other every three years. A third plot was left untouched as a control group.

Paolucci’s colleagues walked through the plots, recording the location of 163 dung piles and comparing them with camera-trap recordings of tapirs roaming through the area. Then the team sieved the fecal findings to separate out seeds, counting a total of 129,204 seeds from 24 plant species. The camera traps showed tapirs spending far more time in burned areas than in the pristine forest, perhaps enjoying the sunshine away from the forest canopy, Paolucci says. The animals also deposited more than three times as many seeds per hectare in burned areas as in the untouched forest.

This 13 May 2020 video is called Tapir dung might help restore degraded tracts of the Amazon | Science News.

Just months after the team published those findings in March of 2019 in Biotropica, the Amazon saw one of its most destructive fire seasons in years (SN: 8/23/19). That made Paolucci even more determined to understand tapirs’ role in forests’ recovery. But he knows the tapirs can’t be doing the job alone.

So Paolucci went back to the insects he began his career with, studying how they might be partners in planting new growth. Tapirs may be leaving fecal fortunes on the forest floor, but dung beetles are actually responsible for pushing the poop around. The insects will break off and bury small pieces of dung, including any seeds within, to snack on later. That helps seed germination get going.

In early 2019, Paolucci returned to the Amazon to collect 20 kilograms of tapir dung, which he broke apart and molded into 700-gram clumps. In each clump, he inserted plastic beads as dummy seeds and then returned the poop pellets to the field. After 24 hours, Paolucci collected the dung clumps again and counted how many beads remained. Those missing had presumably been rolled away by the beetles, and, by proxy, indicated how many seeds would potentially grow into plants one day. Paolucci hopes to publish these results in 2021.

This 13 May 2020 video is called How dung beetles are inadvertent gardeners | Science News.

Amazon ranchers are typically required by law to maintain 80 percent of native forest cover on their properties, but many trees have been illegally cleared and need to be replanted. Tapirs could provide cost-effective help with that effort, Paolucci speculates.

But the population of lowland tapirs, the only tapir species that is widespread throughout the Amazon, is decreasing and is now considered vulnerable, due to habitat loss and hunting for meat. Roughly 20 percent of the Amazon has been destroyed, with another 7 percent expected to be gone by 2030 if current deforestation rates continue. If tapirs fail to thrive, future “seed dispersal is expected to rely even more on organisms such as dung beetles,” Paolucci says.

School staff gets coronavirus infection


This 21 May 2020 video says about itself:

Coronavirus: Elite Sydney school shut after positive COVID-19 test | Nine News Australia

New South Wales Education Treasurer Mark Scott discusses the closure of an elite Sydney boys’ school after a student tested positive to COVID-19.

Translated from Dutch NOS radio today:

At a primary school in Eygelshoven (South Limburg), the coronavirus was diagnosed in four staff members. They have been quarantined, reports regional broadcaster 1Limburg.

The case at primary school De Veldhof came to light when a teacher turned out to be infected. The three other infections emerged from source and contact investigations. …

Parents

All parents have been informed about the infections. As long as their children don’t show symptoms of Covid-19, they can just go to school.

If a person shows symptoms of COVID-19, then it may already be too late. At first sight healthy people, not showing symptoms (yet) may infect others.

Newly born baby in South Africa dies from COVID-19: here.

Respiratory failure has occurred in some infected children and an emerging inflammatory disease may be connected to the coronavirus. By Aimee Cunningham, May 12, 2020.

Wild pansies, little grebes and nightingales


Wild pansies, 20 May 2020

This photo shows wild pansies which we saw on 20 May 2020 in the sand dunes nature reserve, on the day after 19 May.

As we start walking, a blackbird sings. And a chiffchaff.

A cuckoo calls.

A brimstone butterfly.

A wood warbler sings.

We arrive at the hide where we saw little grebes in the lake. This time, we see only a coot couple with their youngsters. The littles grebes are audible, not visible.

A small, but noisy flock of starlings.

Nightingales sing.

A male chaffinch sings from the top of a bush.

Small heath butterflies.

Wild pansies, on 20 May 2020

We arrive at an area with many wild pansies.

Sand dune plants, 20 May 2020

And other plants adapted to this sandy environment.

Rabbit droppings.

We arrive at a lake, not far from Egmond aan Zee village.

Swifts, house martins and barn swallows flying around.

Little grebes, 20 May 2020

Two little grebes swimming.

Coot, 20 May 2020

And a coot.

Stay tuned, as there will be a sequel to this blog post!