Mosses are non-vascular plants that form dense mats, often in damp or shady locations. While people frequently believe they attract insects, moss does not attract bugs with scent or nectar the way a flower attracts a bee. Instead, the plant creates a consistently sheltered microhabitat that arthropods and other invertebrates seek out for survival and reproduction.
Moss: A Microclimate for Arthropods
Moss acts like a natural sponge, absorbing and holding large quantities of water. This moisture retention creates a pocket of high humidity necessary for soft-bodied invertebrates to avoid desiccation. For organisms like slugs, this consistently moist environment is vital for survival.
The dense, interwoven structure of a moss mat provides significant insulation. This physical barrier buffers the organisms living within it from rapid shifts in temperature and humidity, offering a more stable environment. This stability makes moss an ideal refuge from harsh weather and temperature extremes.
Moss offers protection from predators and a complex physical structure for foraging and breeding. The tiny air spaces and miniature forest of stems and leaves provide a network of hiding spots, making it difficult for larger predators to hunt effectively. This stable, multi-dimensional habitat supports higher densities and greater diversity of invertebrates.
Which Creatures Seek Shelter in Moss?
The inhabitants of moss can be separated into beneficial decomposers and garden pests. Pests like slugs and snails are often found in moss because they require high humidity to move and breathe. They use the moist mat as a daytime retreat, emerging only to feed on nearby plants, algae, or fungi, rather than eating the moss itself.
Fungus gnats are another common nuisance. The adult gnats lay their eggs in the consistently moist, organic-rich material of the moss or underlying soil. The resulting larvae feed on the fungi and decaying matter present in the damp conditions, which can sometimes extend to plant roots.
On the beneficial side are springtails, minute arthropods that are essential to healthy ecosystems. These decomposers feed primarily on mold, fungal spores, and decaying plant matter, helping to prevent the buildup of harmful fungi. Springtails are so integrated with moss that they assist in its fertilization by transferring reproductive cells.
Moss mites, a highly diverse group of arachnids, are also abundant within the moss layer. These tiny creatures contribute significantly to nutrient cycling by breaking down organic debris and are often predators of other microscopic invertebrates. The presence of these mites is an indicator of a healthy, functioning soil and moss ecosystem.
Controlling Moss and Associated Pests
The most effective way to control pests associated with moss is to modify the environment so the moss cannot thrive. Moss flourishes where conditions are too shady, too wet, or the soil is too compacted for other plants like turfgrass to grow vigorously. Addressing these root causes prevents the formation of the ideal insect microclimate.
Improving soil drainage is a primary step, often achieved by aerating the soil to reduce compaction and allow for better air and water penetration. In areas with persistent moisture issues, regrading the landscape or installing drainage may be necessary to remove standing water. This reduction in consistent dampness stresses both the moss and the moisture-dependent pests it shelters.
Increasing sunlight exposure by pruning low-hanging tree branches or thinning dense shrub canopies also discourages moss growth. Where shade cannot be eliminated, physically removing the shallow-rooted moss by raking or scraping is effective, followed by reseeding the area with a shade-tolerant groundcover or grass species. By improving conditions for turf or other plants, they can naturally outcompete the moss for resources.
If pests like slugs or fungus gnats become problematic outside the mossy area, targeted management can be used. Slug and snail populations can be reduced with baits or by hand removal. Fungus gnats in houseplants are often managed by allowing the soil surface to dry out completely between waterings. These measures eliminate the pests without relying on broad-spectrum treatments that harm beneficial moss inhabitants.