An interdisciplinary study: farmers' knowledge of functional biodiversity and the effects of restored native vegetation on beneficial invertebrates in a pasture landscape
posted on 2017-05-01, 01:20authored byPeter Paul O'Donnell
There is a growing
consensus among researchers for the need to conserve biodiversity within
agricultural landscapes. Increasingly, research suggests that on-farm
biodiversity is integral to the resilience and sustainability of
agroecosystems. Biodiversity performs a range of ecosystem services in the
agroecosystem such as regulating microclimates, recycling nutrients, augmenting
soils, pollinating crops and supressing pest invertebrate populations. In
particular, the role of invertebrate diversity in providing ecosystem services
on farms is garnering much attention. Invertebrates comprise the bulk of faunal
biomass on farms, are taxonomically diverse, and are the main drivers of many
ecosystem functions. Globally, there are various practices and programs which
are designed to increase biodiversity in agricultural landscapes. Often, these
involve participation by farmers in projects which emphasize restoration of
native vegetation (revegetation of land or protection of remnant native
vegetation) on farmland.
This study investigates the effect of restored native
vegetation on invertebrate communities in southeastern Gippsland, in Victoria,
Australia. In this project, restored native vegetation refers to both blocks of
remnant vegetation and strips of land revegetated with native vegetation, both
of which were protected by fencing from livestock. This study comprises a
series of ecological assessments along with a social study of the role of
farmers in championing and actioning conservation work within agricultural
landscapes.
The ecological component of the study was based on two broad
taxonomic surveys of invertebrate abundances conducted on four farms and one
reference site in the study area. Comparisons of invertebrate abundance were
made at several taxonomic levels, across several vegetation types: restored
native vegetation (either protected areas of remnant native vegetation or areas
revegetated with native vegetation communities), pasture adjacent to restored
native vegetation, pasture remote from native vegetation and a reference site.
Groups of invertebrates considered to be beneficial to agriculture were of
particular interest. At the order level, Araneae generally had higher
abundances in restored native. Four (Asilidae, Tachinidae, Bethylidae, and
Formicidae) of the 11 beneficial invertebrate families had higher abundances in
restored native vegetation. One beneficial invertebrate family (Carabidae) had
consistently higher abundances in pasture adjacent to restored native
vegetation. The highest abundances of the other five beneficial invertebrate
families (Lycosidae, Staphylinidae, Dolichopodidae, Syrphidae, and Apidae)
showed no consistent pattern with regards to vegetation type. One beneficial
invertebrate family (Xylophagidae) was only found in restored native
vegetation. Thirteen of 16 genera of ants were commonly found to have higher
abundances in restored native vegetation. Eight of the 16 genera of ants were
found exclusively in restored native vegetation. Two out of the three
functional groups consistently had higher abundances in restored native
vegetation.
When sampling of invertebrates was undertaken at different
distances from the edge of restored native vegetation, decreases in abundance
from the edge of restored native vegetation to 20m and 80m out into adjacent
pasture were not uncommon for beneficial invertebrates. These results suggest
that beneficial invertebrates may be using restored native vegetation as a
faunal refuge.
The reference site, a low-disturbance area, had unique
invertebrate fauna, with high abundances of some beneficial groups. In addition,
the cores and edges of areas of restored native vegetation had distinct
assemblages of beneficial invertebrates compared to adjacent pasture. These
results indicate that low-disturbance areas and restored native vegetation are
important in increasing the abundance and diversity of beneficial invertebrates
in a pasture landscape.
Farmers in the research area were genuinely interested in
restoring native vegetation on farmland. However, due to dry weather patterns
in the research area, low commodity prices on the world market, and reductions
in agricultural funding, farmers lacked the time and money to restore native
vegetation on farmland. Lack of funding was most commonly identified by farmers
as a barrier to restoration work on farms. Farmers expressed interest in
learning more about the important role of beneficial invertebrates in
controlling pest species in pasture landscapes; and the related role of
restored native vegetation in supporting the abundance and diversity of
beneficial invertebrates on pasturelands. Farmers who are included in
agroecological projects and are presented with the results from these projects
could be more open to undertake restoration work on farms.