1.Their feet are softly padded
At 39 kPA the static load weight of an alpaca is much better than sheep at 82 kPA, cattle at 185 kPA and man at 95 kPA, and even better than kangaroo coming in at 46 kPA. Their soft padded feet do not damage our shallow top soils like other harder hooves livestock and they do not rip out grasses damaging the roots, or ringbark trees, therefore their compaction is less. Damage to topsoil decreases long-term soil fertility, increases soil erosion, and encourages the proliferation of weeds. Alpacas are generally kinder to pasture than sheep, preferring to browse on a variety of plants and grasses, without disrupting root systems. 
2. They cut grasses off with their front incisor teeth while grazing
Unlike cattle (leather) pull up grass by the roots and compress the soil, alpacas use their front incisor teeth to cut grasses off while grazing without disturbing root system. This allows faster pasture recovery and minimizes soil erosion. Alpacas, as browser-grazers, enjoy eating brush, fallen leaves, and other vegetation that is often undesirable to other species.
3. Alpaca Farming using less chemical
Alpacas do well on native grasses and as browsers they tend to select a variety of plants to eat, so biodiversity is maintained and since native pastures require less fertiliser this can in turn reduce waterway contamination from chemical run off. The practice of alpacas to have communal dung piles that they tend to not graze around reduces worm burdens and therefore the need for chemical drenches is also reduced, and the ease of manure collection offers the opportunity for another side line to supplement farm income and improve soil fertility naturally. Due to their clean breach and the lifting of their tail to urinate and defecate, they do not require crutching or mulesing, which is now a major issue for the sheep industry. They tend not to suffer from fly strike or parasites like other livestock and this also reduces the use of chemicals in the farming process. Besides, sheep fleece contains lanolin. As a result, a multi-step detergent wash is needed to remove most of the lanolin prior to processing. Although alpaca also needs to go through a fiber-scouring phase, the chemicals required are fewer and less harsh. Ultimately, alpaca fleeces are relatively easy to process due to this absence of lanolin.
4. They produce more fleece and better quality than sheep
Their fleece grows quickly and is lighter, warmer (meaning it takes fewer strands than wool to insulate), and softer than most sheep wool. Alpacas are not harmed when their fleece is harvested. Alpacas come in wide array of natural colors, offering far more choices for naturally colored yarn and products, as opposed to colors produced using chemical dyes. Manufacturing synthetic fibers is energy-intensive and can release lung-damaging pollutants such as nitrogen and sulfur oxides, particulates, carbon monoxide, and heavy metals into the air, as well as climate-warming carbon dioxide. Alpaca clothing is considered to “breathe naturally,” as it tends to wick moisture and perspiration away from the skin.
5. They have a light environmental footprint
They are finely suited to the harsh conditions of the Peruvian Andes. They eat mostly (native) grass, and sometimes leaves wood, bark or stems. Unlike other grazers, alpacas do not decimate natural vegetation. They consume lower amounts of both water and forage relative to other livestock, and their efficient three-stomach digestive system metabolizes most of what they eat. Researchers at the University of Zurich and ETH Zurich have shown that camelids family (including alpacas) release less methane than ruminants. They produce significantly less of it than ruminants like cattle, sheep and goats.
In summary, alpacas are one of the most sustainable farm animals that worth promoting. On top of their eco friendly nature, they lend enormously to the environmental sustainability of thousands, as alpacas provide wool yearly and allow small farmers to support themselves, their families, and their communities. I hope you enjoy reading this article and you've learned something today. Thank you and have a great weekend ahead!:)