Ecology & Zoology

Trees have been a part of the human existence for as long as humans have existed but that doesn't mean we know everything about them, like why they are the size they are. What limits the height of trees? Is it the fraction of their photosynthetic energy they devote to productive new leaves? Or is it their ability to hoist water hundreds of feet into the air, supplying the green, solar-powered sugar factories in those leaves?

The easy and therefore not vary satisfying answer is that both resource allocation and hydraulic limitation might play a role, but the question still becomes which factor (or what combination) actually sets maximum tree height, and how their relative importance varies in different parts of the world.  


 Humans train animals by rewarding them with tasty treats and trainers couple the reward with a sound, such as a buzz or a whistle. Once the animal has mastered the task, the trainer stops dispensing food, relying instead on the whistle or buzzer to inform the animal that it has performed successfully and that it will be rewarded - with food, but later.

Even though there may be no food reward at the time, whales and dolphins still squeal in response to the sound substituted for the food reward. And Sam Ridgway found that when he trained dolphins and beluga whales to switch off a sound after diving hundreds of meters, the animals produced the same squeals of victory when the sound stopped.  


Conservation wants to preserve nature as it is while wildlife management seeks to maintain responsible levels for animal populations. There is a reasonable balance. In Pennsylvania, for example, there are plenty of state and national park acres but hunting is big business and the fees pay for biologists and state nature management.


Slippery as an eel may be a popular phrase but it turns out they are a lot easier to catch when marine vessels make noise nearby.

In a Global Change Biology paper, researchers from the Universities of Exeter and Bristol found that fish exposed to playback of ship noise lose crucial responses to predator threats - European eels (anguilla anguilla)were 50% less likely to respond to an ambush from a predator, while those that did had 25% slower reaction times.

Those that were pursued by a predator were caught more than twice as quickly when exposed to the noise.  


Juvenile loggerhead turtles don't just passively drift through life, they swim into oncoming ocean currents, according to a new study.


Lanternsharks produce and perceive bioluminescent light in order to communicate, find prey, and camouflage themselves against predators in the mesopelagic twilight zone.

The mesopelagic twilight zone is 200-1000 meters deep in the sea - a vast, dim habitat, where, with increasing depth, sunlight is progressively replaced by point-like bioluminescent emissions. To better understand strategies used by bioluminescent predators inhabiting this region that help optimize photon capture, the authors of a new study analyzed the eye shape, structure, and retinal cell mapping in the visual systems of five deep-sea bioluminescent sharks, including four Lanternsharks (Etmopteridae) and one kitefin shark (Dalatiidae).


It's no surprise that between 1880 and 1920, as the population increased and America became more settled, Missouri, Oklahoma and Arkansas had increased deforestation and that decreased the habitat for black bears and other forest species.

To remedy that and repopulate that mountainous region known as the Central Interior Highlands (CIH), more than 250 bears from Minnesota and Manitoba were relocated to Arkansas in the 1950s and 1960s. Researchers have analyzed genetic diversity in black bears in the 
the Central Interior Highlands
and determined that conservation management has worked, but bears are not out of the woods yet.


A new paper has found that two broad-spectrum systemic insecticides, fipornil and imidacloprid, may be impacting honeybees.

Fipronil, part of the phenylpyrazole chemical family, is a highly effective insecticide which can be applied at very low doses for everything from crop to veterinary pests. Imidacloprid is in the class of chemicals called neonicotinoids - it mimics nicotine, which can be toxic to sucking insects like fleas and termites but has no effect on mammals.
 


More than 10,000 reptile species have been recorded into the Reptile Database, a web-based catalog of all living reptile species and classification, making the reptile species among the most diverse vertebrate groups in the world, alongside bird and fish species, and likely the largest known.

Experts projected that 2014 would mark the year that reptiles would become the most diverse vertebrate group in the world. Reptiles include snakes, lizards, turtles, crocodiles, tuataras and amphisbaenians.


Squids are weird, and then some are weirder. This Bobtail squid was imaged by the Deep Discover ROV in Atlantis Canyon, is less than one foot in length.
This Bobtail squid was imaged by the Deep Discover ROV in Atlantis Canyon, is less than one foot in length.This bobtail squid is very surprised at the absence of squid gynaecologists! Image credit: NOAA OKEANOS Explorer Program