For decades, ecologists have assumed the worst invasive species—such as brown tree snakes and kudzu—have an “away-field advantage.” They succeed because they do better in their new territories than they do at home. A new study led by the Smithsonian Environmental Research Center reveals that this fundamental assumption is not nearly as common as people might think.
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By the time they are born, baby Weddell seal brains have already reached 70 percent of their adult size. (The brain of a human infant is a mere 25 percent of its adult size.) But the researchers found this rapid development carries a hefty price tag.
by Kristen MinogueMost gardeners consider the sight of an earthworm writhing in the dirt a good omen. The slimy invertebrates chew up and churn up the soil, making it easier for vegetables and flowers to access nutrients.
But for wild orchids, they’re more of a menace. Earthworms could prevent roughly half a forest’s orchid seeds from even germinating, ecologists from Smithsonian Environmental Research Center and Johns Hopkins University discovered in a study published online this March in Annals of Botany Plants.
The small size of orchid seeds (they are barely the size of dust grains) makes them particularly vulnerable. As earthworms chew up forest litter, they ingest orchid seeds as well. When that happens, two things can keep the seeds from germinating: One, the process of passing through an earthworm’s gut can render them unviable. Or two, if the seeds survive ingestion, they can end up buried so deep that they can’t access the fungi they need to germinate and grow. As a general rule, deeper soils are much less likely to have those fungi.
by Kristen MinogueThe most bizarre scientific legends sometimes come from completely ordinary creatures. Take, for example, the medieval legend of a tree that gave birth to birds.
A few days ago, marine ecologist Kim Holzer discovered a strange can washed up on a Bermuda beach. Washed-up debris can be dangerous, especially when it comes coated with potential invaders. But this can carried nothing extraordinary—except goose barnacles, the crustaceans that spawned one of the oddest scientific myths in Western history.
by Kristen MinogueMilk—the white, calcium-rich liquid common to mammals and refrigerators across the globe—may have evolved long before the mammals that secrete it. It may have evolved even before dinosaurs. It’s an idea SERC lactation expert Olav Oftedal proposed a decade ago and is now gaining momentum among biologists who study the evolution of what we drink.
by Kristen MinogueIs it better to be a jack of all trades or a master of some? In the plant world, it’s possible to do both–and that could make a huge difference in deciding which plants dominate under climate change. This holds especially true for one: the invasive reed Phragmites australis. Its ability to alter its anatomy enables it to grow well in just about any environment, including one spiked with CO2 and nitrogen, SERC ecologists discovered in a study published Oct. 31.
Plants like this are called “jack-and-master” plants. Typically, the most competitive plants surpass their neighbors through one of two strategies. “Jack-of-all-trades” plants do moderately well under most scenarios. Their competitors will surpass them when conditions are good, but if the environment becomes stressful, the jack of all trades will grow better. “Master-of-some” plants do very well under only a few conditions, so if the environment shifts in their favor, they are certain to emerge victorious. But a few types—the jack-and-master plants—can use both tactics. And the invasive Phragmites is one of them.
by Monaca NobleMost organisms have several types of parasites associated with them. However, when species are introduced, they may lose some of their natural parasites through the invasion process. Or sometimes, parasites that survive the journey don’t do very well in the new environment. In essence invasion acts as a filter limiting the number of parasites that are transported and introduced. In science this process is called the parasite escape hypothesis.
Take the common cat parasite Toxoplasma gondii. T. gondii‘s complex two-host life cycle makes it difficult for it to adapt to new places. The parasite has two phases, a sexual phase and an asexual phase. The sexual phase can only take place in the cat (primary host), but the asexual phase can occur in several mammal species (secondary host) including cats, mice, humans, and birds. Because the parasite must infect a cat to reproduce and survive, its preferred secondary host is a mouse. If a mouse infected with T. gondii were introduced into an area with no cats, the parasite would not be able to survive.
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by Kristen MinogueSome species can survive just about anywhere. Take blue mussels, a group of shellfish whose habitat stretches from the Arctic to the Mediterranean. Over the last several decades, biologists have thrown all kinds of tests at them – heat, cold, saltwater, freshwater, low oxygen. They’ve even tried drying them out. Almost nothing fazes these animals. For invasion scientists trying to figure out how far they could spread, that’s a scary prospect.
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by Monaca NobleRemember Snowmageddon 2010, the east coast storms that dumped up to three feet of snow over the mid-Atlantic? The February snowstorm was the largest in the region in nearly 90 years, resulting in the heaviest snowfall on record for Delaware (26.5 inches) and the third heaviest snowfall in Baltimore (24.8 inches). The storm made a big impression on Dr. João Canning-Clode and other scientists at the Smithsonian Environmental Research Center, who began to wonder if the storm, and the December/January cold snap that preceded it, would lead to the deaths and potential disappearance of marine invaders from southern climates.
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by Kristen Minogue
It’s a trick worthy of any spy thriller: to elude an enemy, hide among something it won’t notice. Or, to be extra safe, something it finds incredibly disgusting. It turns out the same strategy can work for plants that don’t want to get eaten. Sometimes.
For the last seven months, intern Marina LaForgia has kept tabs on tree saplings in more than a dozen different environments and watched the game of ecological survival play out. As she tracked their progress, she searched for an answer to a deceptively simple question: Is diversity good for plants? When it comes to the food chain, will hungry herbivores pass over tasty plants if they’re surrounded by less palatable ones?
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