Direct seeding of indigenous tree and shrub species into New Zealand hill country pasture

Abstract

agresearch.co.nz). This project was part of an indigenous biodiversity restoration research project conducted in the context of a wider integrated catchment management program at the Whatawhata Research Centre, located near Hamilton, New Zealand. SummaryOur study aimed to examine the applicability of a native plant restoration technique involving close grazing, blanket herbicide spraying and mob stocking (to trample the seed into the soil) for establishing New Zealand native tree and shrub species into exotic hill country pasture. This approach represents an alternative to the usual spaced-planting of seedlings in the context of an indigenous vegetation restoration programme. Field-collected seed of Cabbage Tree ( Cordyline australis ), Kahikatea ( Dacrycarpus dacrydioides ), Kanuka ( Kunzea ericoides ), Karamu ( Coprosma robusta ), Kohuhu ( Pittosporum tenuifolium ), Koromiko ( Hebe stricta ), and Manuka ( Leptospermum scoparium ) were germination tested in the laboratory, and broadcast sown in two field experiments in spring 2001 and autumn 2002. The spring-sown experiment tested the effect of mob stocking and the autumn-sown experiment tested the effect of mob stocking and sowing rate. Laboratory germination varied widely among species (0 -88%). In the field, the two shrubs, Koromiko and Karamu, established densities of up to 5 and 1.2 plants/m 2 , respectively, after 2.5 years. Autumn emergence for these two species strongly related to sowing rate. Three tree species, Cabbage Tree, Kahikatea and Manuka, emerged in the field but did not survive beyond 6 months. Mob stocking was effective in spring but not autumn sowing, implicating soil moisture content as an important factor in germination success. The study demonstrated that the direct seeding technique was successful for two shrub species, highlighting the potential for development of a cost-effective native plant restoration approach.

Direct seeding reduces costs, but it is not promising for restoring tropical seasonal forests

“…The most successful direct seeding plantings resulted from few species being sown (e.g. Dodd and Power, 2007;Engel and Parrotta, 2001;Knight et al, 1998). This method is valid for revegetation purposes only, and requires seed dispersal from neighboring sites (Engel and Parrotta, 2001) or the germination of native plants on the site (Cabin et al, 2002) to increase plant diversity.…”

“…Considering the high dependence of seed germination and seedling survival on water, direct seeding plantings are more constrained to the rainy season than seedling plantings (Cabin et al, 2002;Dodd and Power, 2007;Douglas et al, 2007;Knight et al, 1998). Therefore, planting nursery-raised seedlings may be a more attractive method when the revegetation of areas is required for a longer period of the year.…”

Upscaling restoration of native biodiversity: A New Zealand perspective

“…Direct seeding has been used successfully in many countries (Ceccon et al . ) but so far has had limited application in New Zealand (Dodd & Power ; Ledgard et al . ).…”

“…There is considerable potential for the use of direct seeding as a way to reduce costs associated with nurserypropagated plant material. Direct seeding has been used successfully in many countries (Ceccon et al 2016) but so far has had limited application in New Zealand (Dodd & Power 2007;Ledgard et al 2008). A number of challenges occur with direct seeding in abandoned New Zealand farmland, especially in facilitating seeds to germinate in the dense grass sward that dominates many restoration sites.…”

Uso de semeadura direta de espécies arbóreas nativas para restauração florestal de áreas agrícolas, sudeste do Brasil

“…Infelizmente, tal método de restauração florestal tem um alto custo, com investimentos da ordem de R$ 5.000,00 a R$ 8.000,00 ha -1 (FUNDAÇÃO FLORESTAL;FUNDO FLORESTAR, 1994;, dificultando a aplicação do método em larga escala ou mesmo com densidades maiores de plantio, tornando premente a busca por métodos de restauração de baixo custo que possibilitem a rápida colonização das áreas em processo de restauração por espécies nativas. Especialmente devido ao alto custo, alguns pesquisadores têm buscado desenvolver técnicas de restauração alternativas ou complementares ao plantio de mudas, sendo a semeadura direta uma delas (BULLARD et al, 1992;PARROTA, 2001;PARROTA, 2005;AERTS et al, 2006;JINKS, 2006;DODD;POWER, 2007;JINKS, 2009; Figura 12 -A: abertura de covetas para instalação do experimento de enriquecimento florístico da comunidade vegetal formada pela semeadura direta de preenchimento na Área 2. B: detalhe da coveta para semeadura…”