Restoration of mining sites in New Caledonia: history, progress report on seed sector production and development of new techniques using bioengineering
Résumé
New Caledonia possesses up to 25% of the worldwide resources of nickel. Mining exploitation started in 1873 and the ore extraction is done in open pit. Consequently, New Caledonia’s flora and vegetation are directly threatened and local stakeholders are aiming to develop methods to rehabilitate the exploited zone and to restore the original vegetation cover.
The first revegetation trials started in 1971 but ecological restoration capability and concepts have only been developed in the past 15 years. Studies on seed ecophysiology, microorganisms and topsoils are one of the major advancements for restoration. Plantations and hydroseeding are the two major practices used. They both need large seed quantities and the need for seed orchards became evident, but knowledge was poor and several assays were recently carried out. It thus appeared essential to realize a progress report on the seed production sector. At the same time, there was a need to increase restoration methods in particular for extreme areas such as gullies. “NATIVE” and “INNERMINE” projects were dedicated respectively to these subjects.
“NATIVE” revealed that a unique company is dedicated to seed collection and production and needs to be supported. Indeed, regarding seed requirements, production field surfaces must be multiplied by 10 and plant diversity must be increased. Based on observations, on our expertise and on other country practices, we draw up a list of proposals for improvements in the short, medium and long term that will be presented.
“INNERMINE” highlighted that there is an expertise in bioengineering applied and/or applicable. However, it uses exclusively seeds and seedlings. On the other hand, it shows significant deficiencies in the use of cuttings, while this type of material appears particularly well suited in gully context. Subsequently, we recently conducted preliminary experiments and selected demonstration sites. We will present the first encouraging results.