Biodiversity Implications of Agricultural Terrace Abandonment in a Mediterranean Landscapes
Nossan, Hannah
2023-08
Abstract
Dry-stone walls and terraces are a pervasive feature of traditional agriculture systems in many parts of the world and have been used to stabilize hilly slopes for millennia. They play a key role in reducing erosion, increasing rainwater infiltration, and increasing crop productivity. It has also been postulated that dry-stone wall terraces play a key role in increasing and helping to maintain biodiversity especially in the face of a changing climate. They are particularly common in the Mediterranean Basin where they often create a landscape-wide network of pharaonic proportions. Many of these terraces have been increasingly abandoned in recent years because of the high labor costs associated with their maintenance, and due to insufficient agricultural production on marginal lands. Little is known about how the abandonment process affects overall ecosystem function and biodiversity across multiple trophic levels. In this study conducted on the Aegean Island of Naxos, Greece, we build upon previous research which has demonstrated increased biodiversity in proximity to dry-stone walls. Previous research has suggested that terrace abandonment presents a serious threat to the ecological health of Mediterranean habitats (Deng et al., 2021; Newbold et al., 2020; Kruess and Tscharntke, 1994). Here we address two main issues regarding agricultural abandonment. First, we compare three distinct groups of terrace use: (1) active sites which are composed of plowed terraces and maintained supporting walls, (2) semi-active sites which are still plowed but whose supporting walls are not repaired, and (3) abandoned sites which are not used for cultivation, nor receive wall maintenance. Additionally, we use historical records to date the start of abandonment and study the impacts of age since abandonment on the present ecosystem. Measurements of biodiversity, such as reptile and arthropod species richness and population density, as well as measurements of vegetation were recorded to quantify the overall impacts of abandonment on biodiversity and ecosystem function over time. We find that terrace abandonment (via termination of agricultural production) and wall abandonment (via cessation of repairs) have varied effects on resident ecological communities. However, both conditions result in reduced biodiversity compared to actively managed fields. Also, effects vary by trophic level, with the strongest impacts on resident reptiles and arthropods, and the weakest on herbaceous plants. With increasing time since abandonment, we find significant increases in bush encroachment, and significant decreases in species richness and abundance among arthropod and reptile populations. This study suggests that maintenance of dry-stone wall terraces is an important component of ecological management in this region, as these agroecosystems contribute to a more multifunctional landscape.Deep Blue DOI
Subjects
terrace abandonment Mediterranean landscape biodiversity agriculture landscape change
Types
Thesis
Metadata
Show full item recordCollections
Remediation of Harmful Language
The University of Michigan Library aims to describe library materials in a way that respects the people and communities who create, use, and are represented in our collections. Report harmful or offensive language in catalog records, finding aids, or elsewhere in our collections anonymously through our metadata feedback form. More information at Remediation of Harmful Language.
Accessibility
If you are unable to use this file in its current format, please select the Contact Us link and we can modify it to make it more accessible to you.