Land managers and land owners often test multiple revegetation methods out at a small scale before deciding how to implement treatments across a large scale. Often times this information isn't shared in a way that can promote recovery on neighboring lands or in more distant areas that have similar climate and soil conditions. What restoration practices work to improve success of revegetation projects across environmental gradients? RestoreNet is a networked experiment that is finding solutions to some of these challenges and improving success of revegettion across arid landscapes.

Each experimental site tested 3 treatments: above-ground cage-like structures that act as nurse plants (ConMods), at the surface mulch, and below-ground pits. This was coupled with seed mixes of native species found nearby the site and divided into two mixes: cooler and warmer. See the photos above for examples of the different treatments. 

How did seeds respond to treatments?

• Germination of seeds was influenced by treatment and seed mix type.
• Pit and mulch treatments increased seedling density.
• Pits showed the biggest effect of improving seed germination while also limiting non-native species
• Germination also responded in areas with high precipitation in the weeks following germination.

Which seed mix performed better?

Seeded species were grouped into 2 categories at each site based on the climate range of the species.

• The cooler mixes had higher germination success than the warmer mixes. This might be explained by conditions being generally wetter than average across sites in the study year.
• Overall, seeding increased the number of seedlings when compared to control plots that weren't seeded.

General TAKE-HOME MESSAGES for arid lands...

• Consider creating or utilizing areas rich in micro-topography (to perhaps mimic pits) that work to capture sheet flows and increase soil moisture at a small scale and increase success when seeding.
• Consider seeding many species that span adaptations to both cool and warm because we can’t predict the weather with high accuracy.
• Keep an eye on RestoreNet and consider adding a site! We have only completed the first year of the experiment.

Map of locations used in this study in Northern Arizona

Sources/Usage: Public Domain.

How did the treatments compare?

The LEFT figure shows that all treatments increased germination of seeds compared to the control and seed only plots. However, the pit treatment had significantly more germinated seeds. This shows promise for pitting before seeding in places where restoration is difficult.

The RIGHT figure shows how the seed mixes compared. The cooler mix outperfommed the warmer mix in a year where most sites experienced cooler and wetter weather. This shows that land managers may not want to shift to only seeding species expected to thrive in hotter and drier futures.

Sources/Usage: Public Domain.

READ THE PAPER : Havrilla, C.A., Munson, S.M., McCormick, M.L., Laushman, K.M., Balazs, K.R., and Butterfield, B.J., 2020, RestoreNet--An emerging restoration network reveals controls on seeding success across dryland ecosystems online, https://doi.org/10.1111/1365-2664.13715.

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