Newly released non‐native dung beetle species provide enhanced ecosystem services in New Zealand pastures

Abstract

1. Whether the release of non‐native insect species benefits or harms ecosystem services has been the subject of debate. In New Zealand, the release of new non‐native dung beetle species was intended to enhance ecosystem services but concerns were raised over possible negative effects. 2. Field cage trials used three newly released dung beetle species to investigate two concerns: that soil disturbance from dung beetle activity increases soil losses in runoff after rainfall; and that dung burial increases survival of infective parasitic nematodes on pasture. 3. Three treatments – dung + beetles, dung‐only, and controls (without dung or beetles) – were applied on each of three soil types with different permeability: sandy loam, clay loam, and compacted clay. 4. Dung beetle activity resulted in significant reductions of 49% and 81% in mean surface runoff volume, depending on simulated rainfall intensity. Amounts of sediment in the runoff did not change under an extreme rainfall simulation, but in a less extreme rainfall simulation the presence of dung beetles resulted in a 97% reduction in mean sediment amount in runoff. 5. The numbers of infective third‐stage nematode larvae recovered from foliage varied considerably between soil types and through time; however, dung beetle activity reduced overall mean nematode numbers on grass around the dung pats by 71%. 6. This study adds to global evidence that dung beetles can improve agricultural ecosystem services by providing data on services that have rarely been investigated: reduced runoff/soil losses through increased soil porosity, and reductions in parasitic nematodes.

Wood Pastures: A Transitional Habitat between Forests and Pastures for Dung Beetle Assemblages

“…Long-term conservation needs to consider climate change effects and connectivity of suitable dung beetle habitats to provide dispersal possibilities. Active conservation planning is needed, as only sufficiently stable and abundant populations as well as diverse assemblages of dung beetles are able to perform their ecological functions that benefit people [15,75].…”

Global distribution patterns provide evidence of niche shift by the introduced African dung beetleDigitonthophagus gazella

“…The southern latitude limit in South America is in Chillan, Chile (36°S). Its establishment in Victoria, Australia at 36°S (Edwards, 2003) and parts of New Zealand (34–47°S; Forgie et al, 2018) demonstrate the ability of D. gazella to survive in more southerly latitudes. Floate et al (2015) report that D. gazella does not have an obligatory diapause and that the minimum temperature for egg development is 18 °C (with an average egg‐to‐adult development time of 52.2 days at 22 °C, a development threshold of 18 °C equates to 209 degree days).…”

“…Its range expansion has been aided by introduction programs for the biological control of cattle dung on pastures in several regions around the world. These include Australia (Bornemissza, 1970; Tyndale‐Biscoe, 1990; Edwards, 2003, 2007), Brazil (Nascimento et al, 1990), Chile (Ripa et al, 1995), New Caledonia and Vanuatu (Gutiérrez et al, 1988), New Zealand (Forgie et al, 2018), and the USA (Blume & Aga, 1978; Fincher et al, 1983). Adult beetles arrive at fresh dung pats to remove and bury dung in tunnels beneath the pat.…”

Dung beetles as hydrological engineers: effects of tunnelling on soil infiltration

“…Dung beetles are ubiquitous and provide many ecosystem functions and services. They play an important role in bioturbation, secondary seed dispersal, fly population control, nutrient cycling (Nichols et al ., 2008) and may also increase infiltration rates (Brown et al ., 2010; Forgie et al ., 2018). Tunnelling and rolling dung beetle species create tunnels in the soil when nesting or feeding, (Simmons & Ridsdill‐Smith, 2011).…”