What is it about?
Biotic factors such as the presence of invasive animal and/or plant species are well known as major causes of ecological degradation and also as limiting either natural or assisted (human-induced) ecological restoration. However, abiotic aspects of the landscape, such as water availability and soil physical/chemical conditions can also potentially limit restoration and should be considered. Dryland ecosystems are amongst the world’s most threatened and least protected. New Zealand’s drylands have been drastically changed, initially through burning, agricultural and grazing practices and the impacts of introduced herbivores and plants. This research aimed at identifying some of the key environmental factors preventing the reestablishment native woody species in a New Zealand dryland ecosystem. The experiments involved a combination of shading, irrigation and grazing exclusion. The results showed that supplemental water was not beneficial for the survival and growth of the native seedlings, unless combined with shade. Fencing proved important for establishment, even though the species used are regarded in the literature as unpalatable to herbivores. The results indicated that the presence of shade was fundamental for the establishment and growth of the native seedlings likely due to improvements in the microclimate, soil aeration, and water availability to seedlings.
Featured Image
Why is it important?
This study shows that it is crucial to target the environmental factors that hinder both natural and assisted ecological restoration. Restoration of degraded ecosystems is a priority for land management in many different biomes and it is especially important in the globally threatened drylands. The situation in New Zealand’s dryland zone is no different, as it is one of the most endangered and the least well protected ecosystems in the country. Currently, around 30% of the New Zealand dryland zone retains a native vegetation cover with < 2% under legal protection and most of the native vegetation limited to higher altitudes and steeper slopes. Restoration of New Zealand’s dryland ecosystem is urgently required.
Perspectives
This research has helped pinpoint not one but several environmental factors that make ecological restoration difficult for dryland ecosystems in New Zealand. When most restoration efforts seem to target invasive species, for example, the fact that lack of vegetation cover (or some kind of shelter) and degraded soils are seldom taken into account when implementing a restoration plan. Actively planting native seedlings is doomed to fail where their environment has changed over the last decades, as it is the case in most native ecosystems in New Zealand. Ecological restoration has increased chances of succeeding when both biotic and abiotic conditions of the degraded landscape are considered..
Anna Rodrigues
Vitality® New Zealand
Read the Original
This page is a summary of: Ecological Factors Preventing Restoration of Degraded Short Tussock Landscapes in New Zealand’s Dryland Zone, Open Agriculture, August 2017, De Gruyter,
DOI: 10.1515/opag-2017-0048.
You can read the full text:
Contributors
The following have contributed to this page
