Leaf Litter in the Vivarium

The Low Down

Leaf litter is something any of us are familiar with as yard waste. Every year, fallen leaves threaten to smother out our beloved grass (or in my case, that patchwork of moss and dirt that I wish was grass). These fallen leaves cause hours of raking and bagging tree dander. In the jungle, trees have leaves; those leaves have an expiration date, and they have to go somewhere - down! Unlike our yards, there isn't someone to rake them up and haul them to the curb. Instead, a complex network of organisms has developed to break down the fallen leaves and return the nutrients to the food web.

A New World

Years ago, I was fortunate enough to be able to travel to the jungles of Costa Rica. On my first visit to that primeval green landscape known as primary rainforest, I got down on my knees and used a stick to pull back a thick layer of leaves that hugged the forest floor. What I found was somewhat expected, and somewhat a surprise. I expected to see layers upon layers of leaves, about 8-10 inches thick - the uppermost layer intact, then progressively decaying the further down I went until eventually arriving at a basement of rich, black earth.What I did not expect to see what the plethora of life that awaited me. Branches of fungal mats stretched throughout the leaf litter, which was then feasted upon by small insects and arthropods (including springtails!). Larger, predatory invertebrates, such as centipedes and spiders, made short work of the hapless bugs, while higher up, small lizards and frogs hunt for prey. This was where I encountered my first wild dart frog, a Oophaga pumilio, hunting springtails and other small invertebrates at the top layer of leaf litter.

New Beginnings

After this trip, I walked into my frog room and once vibrant tanks, full of colorful frogs and plants, seemed a bit devoid of life. While most tanks did have a thin layer of leaf litter, it didn't support the diverse array of life I saw in the Neotropics. Over the next month, the tanks got extra layers of leaf litter, as well as new species of microfauna. I also realized that, due to the size of the enclosures, there was a limited population the leaf litter could support. I began to experiment with feeding the vivaria in order to keep fungal and microfauna populations high. This was the origin of Josh's Frogs Clean Up Crew Cuisine and Bioactive Booster.I could go on and on about this trip and the impact it had on how I approached animal keeping - I could go on for hours, and we all have things to do. Instead, let's focus on leaf litter - when to use it, what to use it for, and how to get the most out of it.

Leaf litter should be used whenever it's part of the natural habitat for the species in question.

Some animals, such as many small arboreal geckos, may never interact directly with leaf litter in the wild, but it's present below them. Other animals, such as many species of poison dart frogs, have evolved to hunt prey in, on top of, and around leaf litter. Yet other species, such as box turtles, burrow into leaf litter as shelter to hide away from winter, only to emerge in spring. Leaf litter plays a critical role in many of our pets' natural lives. Even if it does not, There's a good chance it plays a significant role in their natural habitat.Leaf litter can be used in many different ways in a habitat. Many times, leaf litter is serving multiple purposes in the enclosure:

As shelter

Leaf litter provides housing for many different organisms. Even in a thick layer of leaf litter, the natural curl of the leaves provides a lot of air pockets and voids for invertebrates to inhabit. Due to their flat shape, leaf litter has a TON of surface area for bacteria and fungi to grow. Larger voids can serve as shelter for larger critters, which may also be able to burrow into the leaf litter when needed. It's these larger critters that are typically the stars of our bioactive enclosures.

As visual barriers

Everyone wants to feel safe, and our pets are no exception. Leaf litter can help block your view of the tank inhabitants, and vice versa. It can also make an enclosure seem a lot more spacious to two tank inhabitants forced to spend their time in close proximity to one another. Leaf litter can also provide feeder insects with places to remain unseen from your pets. This can be both good (it'll take longer for your pet to scarf up its dinner) and bad (feeder insects may be able to avoid being eaten altogether, reproduce in the tank, or grow larger than your pet can eat).

As a source of humidity

Leaf litter will help retain moisture down at the soil layer. This can help raise ambient humidity in the lower reaches of the tank, and provide a humid refuge the tank inhabitants can burrow into. Many beneficial invertebrates, such as springtails and isopods, require high humidity to thrive. A healthy layer of leaf litter can also help keep your plants watered, much like mulch in a flower bed.

As a source of nutrition

Leaf litter provides nutrients for beneficial bacteria and fungi to take hold in the vivarium. It can also play an important dietary function for many different varieties of microfauna. Ultimately, leaf litter ends up as plant food as it decomposes into rich, organic soil.

Decided to use leaf litter in your enclosure?

Great - now, let's look at how you can get the most out of it!

Use a variety of leaves

While any leaf litter is usually better than none, using different types of leaves is a great addition to the bioactive enclosure. This ensures leaves are different shapes and sizes, generally resulting in more voids being present in the mix. It also means leaves will break down at different rates, providing a sustained, long lasting source of nutrition.

Top off regularly

Leaf litter does break down, and since There's not a tree in your tank to drop more of it, you'll have to step in and lend mother nature a hand. As the top layer begins to break down, add a thin layer of new leaves on top. Generally, this'll be every 6 months or so. Try to maintain a 1-3"" layer of leaves.

Seed with microfauna on a regular basis

We all know new tanks should be seeded with springtails and isopods. Ideally, these bugs set up shop in the vivarium, keeping it clean while they reproduce and remain at healthy population levels. Often, these populations are anything but stable - many animals will actively eat them, and some species outcompete others. I add new springtails to my vivaria every month, and new isopods every 3-4 months. This keeps microfauna populations high and my tanks cleaner.

Jumpstart and maintain the biological cycle

Beneficial fungi can be introduced to a new tank to speed up its cycling via Bioactive Booster. After fungi have established and microfauna have been introduced, CUC Cuisine can be offered to help keep microfauna populations high.Reptiles Magazine article titled Natural Vivarium Substrate Recipes can be viewed here http://www.reptilesmagazine.com/Natural-Vivarium-Substrate-Recipes/While this article provides recipes for substrate mixes, it also includes valuable information on using leaves in the vivarium.

Josh's Frogs