38 research outputs found
Smart Moves: Effects of Relative Brain Size on Establishment Success of Invasive Amphibians and Reptiles
Brain size relative to body size varies considerably among animals, but the
ecological consequences of that variation remain poorly understood. Plausibly,
larger brains confer increased behavioural flexibility, and an ability to
respond to novel challenges. In keeping with that hypothesis, successful
invasive species of birds and mammals that flourish after translocation to a new
area tend to have larger brains than do unsuccessful invaders. We found the same
pattern in ectothermic terrestrial vertebrates. Brain size relative to body size
was larger in species of amphibians and reptiles reported to be successful
invaders, compared to species that failed to thrive after translocation to new
sites. This pattern was found in six of seven global biogeographic realms; the
exception (where relatively larger brains did not facilitate invasion success)
was Australasia. Establishment success was also higher in amphibian and reptile
families with larger relative brain sizes. Future work could usefully explore
whether invasion success is differentially associated with enlargement of
specific parts of the brain (as predicted by the functional role of the
forebrain in promoting behavioural flexibility), or with a general size increase
(suggesting that invasion success is facilitated by enhanced perceptual and
motor skills, as well as cognitive ability)
Can Land Managers Control Japanese Knotweed? Lessons from Control Tests in Belgium
Japanese knotweed Fallopia japonica is an
extremely abundant invasive plant in Belgium and surrounding
countries. To date, no eradication method is
available for land managers facing the invasion of this
rhizomatous plant. We tested different chemical herbicides
with two application methods (spraying and stem injection),
as well as mechanical treatments, on knotweed
clones throughout southern Belgium. The tested control
methods were selected to be potentially usable by managers,
e.g., using legally accepted rates for herbicides. Stem
volume, height and density reduction were assessed after
one or two years, depending on the control method. Labor
estimations were made for each control method. No tested
control method completely eradicated the clones. Stem
injection with glyphosate-based herbicide (3.6 kg ha-1 of
acid equivalent glyphosate) caused the most damage, i.e.,
no sprouting shoots were observed the year following the
injection. The following year, though, stunted shoots
appeared. Among the mechanical control methods, repeated
cuts combined with native tree transplanting most
appreciably reduced knotweed development. The most
efficient methods we tested could curb knotweed invasion,
but are not likely to be effective in eradicating the species.
As such, they should be included in a more integrated
restoration strategy, together with prevention and public
awareness campaigns