November 12, 2020

Transitional habitats...from the underwater perspective?

There is something extremely compelling about the water/land relationship that I just can't seem to get enough of, when it comes to aquariums.

We're starting to see more and more aquariums representing the flooded forests, swamps, and wetlands from the underwater perspective. Lots of interesting work with seed pods, branches, and leaves.

We've started to really push out the "Urban Igapo" idea of creating a "wet season/dry season" dynamic in our own aquariums, using terrestrial plants, soils, and other natural materials.

Although, I think we can and should go a little further with these types of representations. Compelling habitats, like wetlands and swamps are fascinating subjects for aquaria. And the irony is that we tend to represent these unique habitats primarily with paludariums and such in aquarium work. We tend not to focus totally in the underwater part, lol.

Now, wetlands in and of themselves are interesting habitats, and include such obsession-inducing ecological niches as mangrove swamps, varzea, and bogs! Wetlands may be saturated with water either seasonally or permanently, and are home to aquatics AND terrestrial plants. They are among the most biologically diverse of all ecosystems- and as such, are a really fascinating subject for our aquarium work, right?

Of course, because there is a most intimate relationship between the water and the surrounding terrestrial environment, it's worth noting that there is a lot of inspiration out there.

The water chemistry of wetland habitats is dependent upon the source of the water and the geological material which it flows through, such as the aforementioned peat swamps, bogs, or mangrove swamps. The soils support biological activity and diversity within the aquatic ecosystem, and provide not only a literal "foundation" for plant growth, but a zone in which various microorganisms, insects, and other life forms thrive, forming the basis of a food chain.

As mentioned previously, many are inundated year-round, although some wetlands are ephemeral in nature, such as the varzea in South America, or even some of those temporary pools you find in the plains of Africa, which are home to some of our favorite annual killifishes, such as Nothobranchius! We've talked about this before, right?

So, if you're thinking what I'm thinking...and I know that you are- the fact is, there are numerous ways to replicate these types of environments in the aquarium!

You can opt to construct something as faithful to the real thing as possible, really trying to be biologically correct- or you could go for something inspired by these habitats. I'm playing with something like that in my brackish water mangrove thicket tank...Mangroves are really great plants to play with in such an aquarium. Especially when we over-emphasize the underwater segment!

And of course, there are also those peat swamps from Southeast Asia, which are a very interesting and distinct ecological niche. With a little research, and use of the right plants and materials, faithful recreations of these habitats are totally achievable! And, as aquarists, it's fun to emphasize the underwater aspect.

And then, you have regions in South America, such as the Pantanal, in which many grasses and other plants create a very unique habitat. One that's begging for more representation in the hobby.

We've talked a lot about flooded forest floors and inundated meadows in the tropical regions of the world, specifically South America and Southeast Asia. Being terrestrial habitats, these forest floors are often covered with shrubs and grasses, many of which are not typically available in the aquarium hobby.

Grasses, such as Paspalum repens, a common species found in South America, and several other grasses, are quite abundant in these habitats, and are most resistant to prolonged submersion. Seeing a formerly terrestrial habitat transformed into an aquatic one is a moth-watering subject for many hobbyists to replicate in aquariums!

And we can do it with some grasses that are available to us.

Now, there are species of Paspalum which are available as seed in many parts f the world, particularly North America and Europe. You absolutely can grow these and utilize them for the "role" of ("generic") "Panatanal grasses" or "forest grasse"s in your displays. Many of them are remarkably tolerant of submersion for brief periods of time!

We as hobbyists can do a lot of work to help figure out which terrestrial plants can tolerate/grow/thrive under submerged or partially submerged conditions. Perhaps a more "realistic" (not in the hardcore "biotope aquarium contest" context, of course) avenue to explore in this regard?

And of course, there are trees, too. I've seen a few tanks beautifully replicate this habitat, both with natural branches/wood and synthetic ones (Beautiful, but, yuck. I know I'll hear it for this..bring on the hate mail...)

Speaking of trees...

I've got one tree for you to research...the dominant terrestrial plant in the South American flooded forests is Eugenia inundata... Don't think I'm not well underway in my (somewhat futile) efforts to see if we can secure fallen leaves or branches of THIS plant! You'll also find Iriartea setigera, Socratea exorrhiza, Mauritiella aculeata palms in these areas..

Get after it, guys...

(Mauritiella aculeata - Image by pixel too used under CC BY 2.0)

Like so many things from the Amazon, it's not easy (read that, damn near impossible) to secure botanical material from this region, so the proverbial "Don't hold your breath waiting for this" comes to mind! Oh, and the submerged grasses we see and drool over in those underwater pics from Mike Tucc and Ivan Mikolji of these habitats?

They're typically Paspalum repens and Oryza perennis.

And we DO have access to some species, such as Sedges and other riparian or semi-aquatic/bog plants from genera that are found in these regions, such as Papyrus (Cyperus), Acorus, Orzyas, etc. These are surprisingly popular plants in the hobby, and for the purpose of recreating one of these seasonally-inundated habitats, they're near perfect!

Since many of these plants tolerate submersion for extended periods of time, they are of great interest to many of us for use in our aquariums. Of course, part of what interests me is that these are generally very hardy plants.

Even when they die off and decompose, they form a compelling niche in the underwater environment. A rich, diverse, and productive habitat.

There are numerous species more commonly available from commercial nurseries in North American and European nations, so creating realistic representations of these habitats in our aquariums is more attainable than ever! Acorus is my fave.

Now, with this in mind, there are also lots and lots of possibilities for creating unique aquatic displays with what I would call "aquatic analogs" of these grasses and shrubs. In other words, incorporating some true aquatics to replicate the "look" of the flooded forests using representative species. I mean, we are talking about the "underwater perspective", right?

I freely admit that this is a total "cheat"- but when you think about it, it's a pretty good method that can be employed if you want to represent the inundation period from the underwater perspective for the theme of your aquarium, and aren't able to secure or grow the terrestrial/semi-aquatic analogs to the species found in these habitats.

I know a few that could work!

I'm thinking about plants like Echinodorus tenellus, the "Pygmy Chain Sword", which grows in a most "grasslike" state, and certainly is representative of the grasses one might find on a flooded Panatanal or forest floor habitat in South America.

It's not hard to cultivate a little section of these plants in your representation of a flooded forest, and drop in a few leaves and botanicals, and achieve a relatively realistic-looking facsimile of the flooded grasslands from this underwater perspective.

Another great candidate that has a sort of "generic tropical terrestrial grasslike" appearance would be Cryptocoryne parva. This diminutive plant actually can be grown emerged, so for "semi-flooded" igapo or varzea biotope aquariums, it would be really adaptable! And when submerged, it bears strong resemblance to Paspalum or other tropical, submersion-resistant grasses. (It's the plant in the foreground in the below pic, BTW)

Geographic transgressions aside, it's an interesting subject for this purpose.

I suppose the old fave, Sagittaria, could also be employed for this purpose, but some species can achieve a larger size and perhaps ultimately be not as realistic, so you'd need to choose carefully. More exotic, but readily available as tissue-cultured, would be the beautiful Lilaeopsis mauritiana, a beautiful species often called "Micro Sword" for its appearance and size.

Yeah, a lot of aquatic plant candidates here.

And of course, since we're representing a flooded forest floor or meadow, with patchy growth over rich soil and leaves, you likely don't need to have the full-on green lawn that planted aquarists strive for so ardently!

A little bit of "open space" and some twigs, roots, bark pieces, a few seed pods, and exposed substrate and you're well on your way to creating a remarkably cool tank! In fact, you can omit the plants altogether, and replicate the "late season" inundation, when most of the terrestrial vegetation has either went dormant or died off.

The idea of representing the terrestrial habitats during their submerged phase as the subject of your aquarium is really compelling. There's plenty of room for creativity, experimentation, and yes- breakthroughs.

Stay inspired. Stay curious. Stay creative. Stay excited...

And Stay Wet.

Scott Fellman

Tannin Aquatics