Feral Horses Gallop to the Rescue of Butterflies in Distress
By Nanticha Ocharoenchai
In the Czech Republic, horses have become the knights in shining armor. A study published in the Journal for Nature Conservation suggests that returning feral horses to grasslands in Podyjí National Park could help boost the numbers of several threatened butterfly species.
In 2017, wildlife organizations laid out their plan to introduce Exmoor ponies (Equus ferus caballus) to the dry, temperate grasslands of Podyjí along the Czech border with Austria. They aimed to "rewild" the region and restore natural ecosystems by allowing the land and its native species to develop free from human influence.
At the same time, a team of researchers led by Martin Konvička, a researcher at the University of South Bohemia in the Czech Republic, began monitoring butterfly species in the reintroduction sites to predict how they would respond to this "refaunation," as scientists call the reintroduction of animals. Their results showed that the horses' grazing would likely improve conditions for many of the butterfly species that live in the area.
It turns out that horses encourage habitats that many butterflies flock to. By trampling and feeding on tall shrubs, young twigs and fruits, horses keep the grasslands short, which some butterfly species prefer. They also don't disturb the land as much as mowing or more intensive livestock grazing would.
Konvička and his team studied the population size, movements and larvae of five species of checkerspot butterflies, including four that are listed as endangered or critically endangered nationally. For more than two months, the researchers scoured the park's fields to find as many butterflies as possible. They marked them with unique codes using felt-tip pens and took note of their species, sex and wing wear on a scale of "fresh" to "heavily worn." Then they released them, only to repeat the procedure the next day.
To study checkerspots, Konvička said, "you need a group of dedicated people at the spot, ready to work every day with no days off for most of the summer, when most humans prefer to be at a beach."
The researchers' analysis allowed them to predict how the butterflies might respond to the reintroduction. The results showed that each species tends to specialize in different habitats. Some prefer short grass and woodland edges, and others like exposed rocks and ditches.
"The ongoing insect/pollinator crisis is at least partly due to homogenization of land use in agriculture, forestry, et cetera," Konvička said in an email. In other words, these human impacts are making landscapes more uniform with less variety, reducing the chances that they'll provide the right habitat for multiple species of butterflies.
That means "everything which brings back a semblance to pre-industrial/prehistoric conditions will help," Konvička added.
One of the organizations involved in this project, the nature conservation NGO European Wildlife, decided to replicate their refaunation efforts after the success of reintroducing Exmoor ponies to a former military base in Milovice, also in the Czech Republic. That project demonstrated how butterflies benefited from the presence of Exmoor ponies, a breed native to the British Isles. They're also one of the oldest and most primitive horse breeds in Europe and handle cold weather well.
Dalibor Dostal, director of European Wildlife, said part of the challenge was "to give people confidence in natural processes."
Four of the studied butterfly species prefer habitats that horses help create and maintain. But the study also shows that the rarest of the five species, the Assmann's fritillary (Melitaea britomartis), will likely be threatened by the reintroduction due to the decrease of tall vegetation that it prefers.
The study site, which is also a former military base, was once home to other species like the hermit butterfly (Chazara briseis). The concrete military structures and ecological changes left behind from World War II drove out some species, but they created ideal living conditions for the Assmann's fritillary. The reintroduction of the horses will likely transform the landscape again.
Konvička said that studies like this one could help predict those impacts before they occur.
"Detailed knowledge of [the ecology] of focal insects may point to rewilding-associated risks," he said.
He recommended the regulation of horse population sizes, as well as incrementally enlarging the project sites to avoid the risk of overgrazing, which could clip down the vegetation to a uniform length that's not ideal for many butterflies.
"I think the introduction of feral horses in such dry grasslands is an excellent idea," said Roel van Klink, a researcher at the German Centre for Integrative Biodiversity Research at the University of Leipzig, who was not involved in the study.
"At this moment many such grasslands face abandonment, because appropriate management with livestock is very expensive," van Klink said in an email. "We know that if no management would take place at all, such grasslands would turn into … cold, dark forests with not much undergrowth. This would certainly lead to the extinction of all five butterfly species from the site."
Konvička said he believes many projects neglect the role of missing "ecological engineers" — sometimes called "ecosystem" engineers — that is, species that serve significant functions through the alteration, maintenance or destruction of habitats. As with the Exmoor ponies in this case, they may not be the original inhabitants, but the aim of rewilding is to get the ecosystem functioning again.
"At the scale of national parks, restoring all the missing ecosystem components is the only way in the long term," he said.
Nanticha Ocharoenchai is a communications graduate and environmental writer from Thailand, where she initiated the climate strike movement.
Reposted with permission from Mongabay.
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By Bob Jacobs
Hanako, a female Asian elephant, lived in a tiny concrete enclosure at Japan's Inokashira Park Zoo for more than 60 years, often in chains, with no stimulation. In the wild, elephants live in herds, with close family ties. Hanako was solitary for the last decade of her life.
Hanako, an Asian elephant kept at Japan's Inokashira Park Zoo; and Kiska, an orca that lives at Marineland Canada. One image depicts Kiska's damaged teeth. Elephants in Japan (left image), Ontario Captive Animal Watch (right image), CC BY-ND
Affecting Health and Altering Behavior<p>It is easy to observe the overall health and psychological consequences of life in captivity for these animals. Many captive elephants suffer from arthritis, obesity or skin problems. Both <a href="https://doi.org/10.11609/JoTT.o2620.1826-36" target="_blank">elephants</a> and orcas often have severe dental problems. Captive orcas are plagued by <a href="https://doi.org/10.1016/j.jveb.2019.05.005" target="_blank">pneumonia, kidney disease, gastrointestinal illnesses and infections</a>.</p><p>Many animals <a href="https://doi.org/10.1016/j.neubiorev.2017.09.010" target="_blank">try to cope</a> with captivity by adopting abnormal behaviors. Some develop "<a href="https://doi.org/10.1016/j.applanim.2017.05.003" target="_blank" rel="noopener noreferrer">stereotypies</a>," which are repetitive, purposeless habits such as constantly bobbing their heads, swaying incessantly or chewing on the bars of their cages. Others, especially big cats, pace their enclosures. Elephants rub or break their tusks.</p>
Changing Brain Structure<p>Neuroscientific research indicates that living in an impoverished, stressful captive environment <a href="https://doi.org/10.1016/j.jveb.2019.05.005" target="_blank" rel="noopener noreferrer">physically damages the brain</a>. These changes have been documented in many <a href="https://doi.org/10.1002/cne.903270108" target="_blank" rel="noopener noreferrer">species</a>, including rodents, rabbits, cats and <a href="https://doi.org/10.1006/nimg.2001.0917" target="_blank" rel="noopener noreferrer">humans</a>.</p><p>Although researchers have directly studied some animal brains, most of what we know comes from observing animal behavior, analyzing stress hormone levels in the blood and applying knowledge gained from a half-century of neuroscience research. Laboratory research also suggests that mammals in a zoo or aquarium have compromised brain function.</p>
This illustration shows differences in the brain's cerebral cortex in animals held in impoverished (captive) and enriched (natural) environments. Impoverishment results in thinning of the cortex, a decreased blood supply, less support for neurons and decreased connectivity among neurons. Arnold B. Scheibel, CC BY-ND<p>Subsisting in confined, barren quarters that lack intellectual stimulation or appropriate social contact seems to <a href="https://doi.org/10.1590/S0001-37652001000200006" target="_blank" rel="noopener noreferrer">thin the cerebral cortex</a> – the part of the brain involved in voluntary movement and higher cognitive function, including memory, planning and decision-making.</p><p>There are other consequences. Capillaries shrink, depriving the brain of the oxygen-rich blood it needs to survive. Neurons become smaller, and their dendrites – the branches that form connections with other neurons – become less complex, impairing communication within the brain. As a result, the cortical neurons in captive animals <a href="https://doi.org/10.1002/cne.901230110" target="_blank">process information less efficiently</a> than those living in <a href="https://doi.org/10.1002/dev.420020208" target="_blank">enriched, more natural environments</a>.</p>
An actual cortical neuron in a wild African elephant living in its natural habitat compared with a hypothesized cortical neuron from a captive elephant. Bob Jacobs, CC BY-ND<p>Brain health is also affected by living in small quarters that <a href="https://doi.org/10.3233/BPL-160040" target="_blank">don't allow for needed exercise</a>. Physical activity increases the flow of blood to the brain, which requires large amounts of oxygen. Exercise increases the production of new connections and <a href="http://dx.doi.org/10.1126/science.aaw2622" target="_blank">enhances cognitive abilities</a>.</p><p>In their native habits these animals must move to survive, covering great distances to forage or find a mate. Elephants typically travel anywhere from <a href="https://www.elephantsforafrica.org/elephant-facts/#:%7E:text=How%20far%20do%20elephants%20walk,km%20on%20a%20daily%20basis." target="_blank">15 to 120 miles per day</a>. In a zoo, they average <a href="https://doi.org/10.1371/journal.pone.0150331" target="_blank" rel="noopener noreferrer">three miles daily</a>, often walking back and forth in small enclosures. One free orca studied in Canada swam <a href="https://doi.org/10.1007/s00300-010-0958-x" target="_blank" rel="noopener noreferrer">up to 156 miles a day</a>; meanwhile, an average orca tank is about 10,000 times smaller than its <a href="https://www.cascadiaresearch.org/projects/killer-whales/using-dtags-study-acoustics-and-behavior-southern" target="_blank" rel="noopener noreferrer">natural home range</a>.</p>
Disrupting Brain Chemistry and Killing Cells<p>Living in enclosures that restrict or prevent normal behavior creates chronic frustration and boredom. In the wild, an animal's stress-response system helps it escape from danger. But captivity traps animals with <a href="https://doi.org/10.1073/pnas.1215502109" target="_blank">almost no control</a> over their environment.</p><p>These situations foster <a href="https://doi.org/10.1037/rev0000033" target="_blank">learned helplessness</a>, negatively impacting the <a href="https://doi.org/10.1155/2016/6391686" target="_blank" rel="noopener noreferrer">hippocampus</a>, which handles memory functions, and the <a href="https://doi.org/10.1016/j.neuropharm.2011.02.024" target="_blank" rel="noopener noreferrer">amygdala</a>, which processes emotions. Prolonged stress <a href="https://doi.org/10.3109/10253899609001092" target="_blank" rel="noopener noreferrer">elevates stress hormones</a> and <a href="https://doi.org/10.1523/JNEUROSCI.10-09-02897.1990" target="_blank" rel="noopener noreferrer">damages or even kills neurons</a> in both brain regions. It also disrupts the <a href="https://doi.org/10.1016/j.neubiorev.2005.03.021" target="_blank" rel="noopener noreferrer">delicate balance of serotonin</a>, a neurotransmitter that stabilizes mood, among other functions.</p><p>In humans, <a href="https://doi.org/10.1006/nimg.2001.0917" target="_blank" rel="noopener noreferrer">deprivation</a> can trigger <a href="https://doi.org/10.3389/fnins.2018.00367" target="_blank" rel="noopener noreferrer">psychiatric issues</a>, including depression, anxiety, <a href="https://doi.org/10.3389/fnins.2018.00367" target="_blank" rel="noopener noreferrer">mood disorders</a> or <a href="https://doi.org/10.1177/1073858409333072" target="_blank" rel="noopener noreferrer">post-traumatic stress disorder</a>. <a href="https://doi.org/10.1007/s00429-010-0288-3" target="_blank" rel="noopener noreferrer">Elephants</a>, <a href="https://doi.org/10.1371/journal.pbio.0050139" target="_blank" rel="noopener noreferrer">orcas</a> and other animals with large brains are likely to react in similar ways to life in a severely stressful environment.</p>
Damaged Wiring<p>Captivity can damage the brain's complex circuitry, including the basal ganglia. This group of neurons communicates with the cerebral cortex along two networks: a direct pathway that enhances movement and behavior, and an indirect pathway that inhibits them.</p><p>The repetitive, <a href="http://dx.doi.org/10.1016/j.bbr.2014.05.057" target="_blank">stereotypic behaviors</a> that many animals adopt in captivity are caused by an imbalance of two neurotransmitters, dopamine and <a href="https://doi.org/10.1016/j.neubiorev.2010.02.004" target="_blank" rel="noopener noreferrer">serotonin</a>. This impairs the indirect pathway's ability to modulate movement, a condition documented in species from chickens, cows, sheep and horses to primates and big cats.</p>
The cerebral cortex, hippocampus and amygdala are physically altered by captivity, along with brain circuitry that involves the basal ganglia. Bob Jacobs, CC BY-ND<p>Evolution has constructed animal brains to be exquisitely responsive to their environment. Those reactions can affect neural function by <a href="https://www.penguinrandomhouse.com/books/311787/behave-by-robert-m-sapolsky/" target="_blank">turning different genes on or off</a>. Living in inappropriate or abusive circumstance alters biochemical processes: It disrupts the synthesis of proteins that build connections between brain cells and the neurotransmitters that facilitate communication among them.</p><p>There is strong evidence that <a href="https://doi.org/10.1523/JNEUROSCI.0577-11.2011" target="_blank">enrichment</a>, social contact and appropriate space in more natural habitats are <a href="https://doi.org/10.1111/j.1748-1090.2003.tb02071.x" target="_blank" rel="noopener noreferrer">necessary</a> for long-lived animals with large brains such as <a href="https://doi.org/10.1371/journal.pone.0152490" target="_blank" rel="noopener noreferrer">elephants</a> and <a href="https://doi.org/10.1080/13880292.2017.1309858" target="_blank" rel="noopener noreferrer">cetaceans</a>. Better conditions <a href="https://www.ncbi.nlm.nih.gov/pmc/articles/PMC5543669/" target="_blank" rel="noopener noreferrer">reduce disturbing sterotypical behaviors</a>, improve connections in the brain, and <a href="https://doi.org/10.1038/cdd.2009.193" target="_blank" rel="noopener noreferrer">trigger neurochemical changes</a> that enhance learning and memory.</p>