The idea of using leaves and botanicals in the aquarium to influence the function and/or aesthetics of the environment is not some "new" concept; indeed, hobbyists have been doing this in one form or another for many decades.
I think that what's different is that we are now accepting the use of these materials for a combination of reasons- what we call "functional aesthetics"- the capability of a material to influence the look and the function of the aquarium environment simultaneously.
A real "mental shift..."
Some hobbyists have commented that, as their leaves and botanicals break down the scape as initially presented changes significantly over time. Wether they know it or not, they are grasping "Wabi-Sabi"...sort of. One must appreciate the beauty at various phases to really grasp the concept and appreciate it. To find little vignettes- little moments- of fleeting beauty that need not be permanent to enjoy.
And, despite their impermanence, these materials function as diverse harbors of life, ranging from fungal and biofilm mats, to algae, to micro crustaceans and even epiphytic plants. Decomposing leaves, seed pods, and tree branches make up the substrate for a complex web of life which helps the fishes that we're so fascinated by flourish.
And, if you look at them objectively and carefully, these assemblages are beautiful.
This is not something new or previously unconsidered by the hobby, but it's something we don't give much thought to, I think. Of course, when we look at natural ecosystems where leaves and other botanical materials collect, the parallels in look and function become far more obvious!
Understanding the transient nature of botanical materials is absolutely essential for the botanical-style aquarium enthusiast. There are many who prefer a crisp, clean collection of botanicals and leaves in their tanks, and go to great effort to keep them that way...They will remove any leaf that starts to break down or recruit biofilms, and replace them with new ones. If you're up to the task- I say go for it!
For most of us- those of us who've made that mental shift- we let Nature dictate the evolution of our tanks. We understand that the processes of biofilm recruitment, fungal growth, and decomposition work on a timeline, and in a manner that is not entirely under our control.
Decomposition is an amazing process by which Nature processes materials for use by the greater ecosystem. It's the first part of the recycling of nutrients that were used by the plant from which the botanical material came from. When a botanical decays, it is broken down and converted into more simple organic forms, which become food for all kinds of organisms at the base of the ecosystem.
In aquatic ecosystems, much of the initial breakdown of botanical materials is conducted by detritivores- specifically, fishes, aquatic insects and invertebrates, which serve to begin the process by feeding upon the tissues of the seed pod or leaf, while other species utilize the "waste products" which are produced during this process for their nutrition.
In these habitats, such as streams and flooded forests, a variety of species work in tandem with each other, with various organisms carrying out different stages of the decomposition process.
We just plug along, feeding our fishes, doing water exchanges, and growing plants. We tend to our aquascapes, and watch things grow. And, over time, even the most diligently-maintained aquariums tend to look significantly different than when they did when they were first assembled.
It's how natural systems go.
There will be change. There will be decomposition.
If we allow it to happen. If we accept that some parts of the evolution of our aquariums are beyond our control.
Think about that!
Stay curious. Stay creative. Stay thoughtful. Stay bold...
And Stay Wet.