Seed-Based Restoration

HVNP found ʻaʻaliʻi to regenerate readily on its own post-fire, leading to a shift in species-selection to focus on species that have lower potential for natural recovery post-fire. Recovery appears to vary given pre-fire vegetation, with different restoration strategies appropriate for bunch grass (Broomsedge, Andropgon sp.) vs. mat grass (Kikuyu, Cenchrus clandestinus). Furthermore, they expressed a desire to target areas with high burn severity.

 

Over their monitoring period, WDFI has seen that long-term weed management has a direct correlation with increased number of stems, plant vigor, and overall plant height for native species. At the time of this presentation, Koʻokoʻolau was on its 4th or 5th generation, ʻāweoweo was continuing to seed with new plants beginning to germinate, and ʻaʻaliʻi fruit was becoming a visible component of the leaf litter/ soil.
 

NNRM highlighted the need to anticipate catastrophic events (fires) and value of prepping ahead of time. Projects require flexibility and being able to adapt when changes come up is key. When working in remote sites, small problems can easily become big ones. Budgeting time (and finances) with these considerations in mind with behove you and the success of your project.

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All the programs found that the amount of seeds that were in storage were not enough to address their post-fire restoration needs and emphasized the need for more seed collection of a wider diversity of species to be able to conduct effective and timely post-fire restoration. HVNP, relying heavily on ~15 years of seed collection broadcast around 2 million seeds in over 1,000 acres. In contrast, WDFI broadcast over 3.6 million ʻaʻaliʻi seeds alone across their 21.5 acre restoration site and NNRM broadcast 172 lbs of seed by helicopter--with ~116 lbs of those seeds consisting of over 22 million seeds.

 

While both WDFI and NNRM benefited from historic collection efforts, they keenly demonstrate the effort required to prepare for large-scale, seed-based restoration. In particular, they highlight a need to shift from opportunistic collections to dedicated teams with focused collection targets to overcome collection challenges such as inter-annual variation and founder limitations and ultimately to acquire have the right seed at the right time, and from the right place.

 

There are still outstanding storage limitations, including unknown viability of seeds in storage without conducting time-intensive germination/viability trials and certain species do not store well, both leading to an ongoing need to recollect to keep enough viable seed on hand. Lack of germination trials also leads to questions of how much of seed broadcasted are actually viable. 

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Questions surrounding founder diversity remain, especially when a project has access to only a few wild individuals. In a later part of the forum, groups discussed potential frameworks for evaluating seed zones for a given species. Some key questions include origin (indigenous vs endemic), dispersal mechanism, and historic ranges of bird dispersers.

As the capacity to conduct seed-based restoration continues to grow, the question remains–What do we charge for a pound of seeds? Given current tools, a single pound of seed may take upwards of 50 hours to collect and process. As demonstrated throughout these presentations seed collection and processing are both time consuming. Place-based knowledge is central to seed collection, a knowledge base that takes time and practice to develop and as such, seed collectors are specialists. As collection efforts increase, there is a need for more efficient tools to process large seed batches.

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Seed-based restoration goes hand-in hand with an increase in the collection and storage of common seeds. Ungulate exclusion is going to be necessary for most species. Weed management can have a positive impact on restoration success.​​