No abstract

15Afforestation can improve the delivery of ecosystem services from reclaimed landfill sites. 16 Tree health is a key determinant of ecosystem service delivery, and is directly impacted by 17 soil quality; which is driven by biological processes in the soil, reliant on leaf litter inputs to

Woodland restoration is underway globally to counter the negative soil quality and ecological impacts of agricultural expansion and woodland fragmentation, and restore or enhance biodiversity, ecosystem functions and services. However, we lack information about the long‐term effects of woodland restoration on agricultural soils, particularly at temporal scales meaningful to woodland and soil development. This study utilized soil and earthworm sampling across a chronosequence of sites transitioning from “agricultural land” to “secondary woodland” (50–110 years) and “ancient woodland” (>400 years), with the goal of quantifying the effects of woodland restoration on agricultural land, on key soil quality parameters (soil bulk density, pH, carbon and nitrogen stocks, and earthworm abundance, biomass, species richness and diversity). Broad‐leaved woodland restoration led to significantly greater soil organic carbon (SOC) stocks compared to arable land, and young (50–60 years) secondary woodland increased earthworm species and functional diversity compared to both arable and pasture agricultural land. SOC stocks in secondary broad‐leaved woodlands (50–110 years) were comparable to those found in long‐term ancient woodlands (>400 years). Our findings show that broad‐leaved woodland restoration of agricultural land can lead to meaningful soil ecological improvement and gains in SOC within 50–110 years, and provide intel on how restoration activities may be best targeted to maximize soil quality and functions.

Background: The ecological importance of deadwood is widely acknowledged, however popular forestry practices may reduce deadwood from a site, and most European forests now fall below recommended targets, putting deadwood-associated species at risk. There is increasing evidence that earthworm species which live in alternative habitats such as deadwood can be missed by traditional sampling methods, which can lead to false classifications regarding species distributions and conservation status and value. Resolving the current lack of a systematic and quantitative methodology for surveying earthworms in microhabitats such as deadwood may therefore lead to valuable insights into earthworm species ecologies in forest ecosystems. The main aim of this research was to develop and trial a systematic method for surveying deadwood-associated earthworms, with potential future application to other invertebrates. Sampling of earthworms within soil, deadwood and soil beneath deadwood was carried out across a chronosequence of unmanaged oak forest stands. The results were then used to investigate the influence of soil and deadwood environmental factors and woodland age on the earthworm populations of oak-dominated broadleaf woodlands. Results: Results from our surveys successfully show that in oak woodland habitats with deadwood, omitting deadwood microhabitats from earthworm sampling can lead to underestimates of total earthworm species richness, abundance and biomass. We also found a significantly greater proportion of juveniles within the earthworm communities of broadleaf deadwood, where temperature and moisture conditions were more favourable than surrounding open soil habitats. Conclusions: The systematic method presented should be considered as additional and complementary to traditional sampling protocols, to provide a realistic estimate of earthworm populations in woodland systems. Adopting this quantitative approach to surveying the biodiversity value of deadwood may enable forest management practices to more effectively balance wood production against ecological and conservation values. Opportunities for further development of the sampling methodology are proposed.

On reclaimed landfill sites, the addition of organic matter such as composted green waste (CGW) to soil-forming materials can support tree survival and growth. CGW addition may also assist the establishment of sustainable earthworm populations, and in turn these organisms can promote further soil development through their burrowing and feeding activity. Despite such potentially mutual benefits, little research has been carried out into CGW and earthworm interactions with trees on reclaimed land. A twelve month, open field nursery experiment revealed the responses of the interactions between two tree species; Alnus cordata (Betulaceae) and Acer platanoides (Sapindaceae), CGW and the earthworms Aporrectodea longa (Lumbricidae) and Allolobophora chlorotica (Lumbricidae) in reclaimed soil. Controlled mesocosm conditions permitted a detailed investigation into the factors affecting tree growth and nutrient uptake, soil nutrient cycling and earthworm population dynamics. Results revealed that A. cordata growth was unaffected by CGW or earthworm addition. There was, however, a significant positive synergistic effect of earthworm activity and CGW addition on A. platanoides growth. CGW addition significantly increased levels of organic carbon and essential plant macro-nutrients in reclaimed soil while earthworm activity assisted decomposition of both leaf litter and CGW. Findings showed that CGW may serve as a suitable early source of organic matter to support earthworm population establishment on reclaimed sites. This experiment demonstrates that CGW improves reclaimed soil quality, thereafter supporting tree establishment and growth on reclaimed landfill.