Thank you gorillas!
Open canopy, a sign of successShould we be grateful to the gorillas? It would seem natural to think so because without the existence of these and other animals and their contribution to the effective dispersal of seeds fertilized by their fecal matter (thereby supplying minerals and humidity), these seeds would have less chance of developing into healthy and vigorous plants and therefore into plants that can be beneficial for humans as well. Another observation corroborates this assessment: the seedlings develop much better under an open canopy than in the forest where the light cannot penetrate. “The positive effect of dropping seeds in open habitats has already been mentioned, but this is the first time that the role of light has been directly demonstrated. In order to quantify this, I used hemispherical photographs of the canopy (at 360°C) taken vertically from the ground. Using softwares, I was able to transform the pictures into contrasting black and white images revealing the percentage of the canopy that was open. It emerged that the canopy around the gorilla nest sites showed a 7% to 10% level of openness. Apart from these sites, where the canopy was closed, the level of openness was only around 2% or 3%. The difference may not seem much but it is a determining factor: the seedlings develop two to ten times more rapidly in the open sites. Luminosity in tropical forests is a fundamentally important factor”. The privilege of certified forestsAs of now, it would certainly be a step too far to draw the conclusion that the gorillas show a preference for artificial felling light gaps and therefore contribute directly to the conditions necessary for regeneration of human-exploited forests. “Over the three years, I compiled three nest-site inventories: one of these was done just before the loggers had passed through the area, a second just after they had passed followed by a third 12 months later. I wanted to observe whether the gorillas showed a preference for areas that were open by logging activities. This would have given credence to the idea that when forest exploitation is practiced in a sustainable way, it is beneficial to the gorillas because it creates new habitats for them. This was not seen to be the case but this was probably because it was too early: the herbaceous plants had not yet had time to regenerate sufficiently. In my opinion, it is just a matter of time”. |
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© 2007 ULi�ge
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