Impact of Phytophthora-dieback on birds in Banksia woodlands in south west Western Australia

Abstract

Invasive plant pathogens have impacted forest and woodland systems globally and can negatively impact biodiversity. The soil-borne plant pathogen Phytophthora cinnamomi is listed as one of the world's worst invasive species and alters plant community composition and habitat structure. Few studies have examined how these Phytophthora-induced habitat changes affect faunal communities.We examined bird communities in Banksia woodland with, and without, Phytophthora dieback in a biodiversity hotspot, southwestern Australia. Seven sites along dieback fronts, with paired 1-ha plots in diseased and healthy vegetation, were surveyed monthly for birds over seven months. Vegetation assessments showed that diseased sites had reduced plant species richness, litter, shrub, tree and canopy cover, high bare ground and significantly lower flowering scores, than healthy sites. Bird community composition differed significantly between diseased and healthy sites, although total bird abundance, total species richness and foraging guilds, did not. Average species richness of birds per survey and the abundance of brown honeyeaters, western spinebills and silvereyes was lower in diseased than healthy sites. The tawny-crowned honeyeater had higher abundances in diseased sites.Similarity matrices of habitat structure, flowering scores and bird assemblages were congruent, indicating that habitat structural differences were influencing bird community composition. Our results suggest that this pathogen is potentially a serious threat to avian biodiversity and especially for nectarivores, and populations in fragmented landscapes. Since elimination of the pathogen is not currently possible, management should focus on methods of preventing its spread until techniques to eliminate the pathogen are developed.

Effectiveness of camera traps for quantifying daytime and nighttime visitation by vertebrate pollinators

“…40% of species listed as threatened flora are pollinated by vertebrates (Brown et al., ; Keighery, ). Here, several species of nectarivorous vertebrates are experiencing population decline in landscapes negatively impacted by land clearing, habitat fragmentation, introduced species, climate change and/or disease (Davis, Gole, & Roberts, ; Davis et al., ; How & Dell, ; Phillips, Hopper, & Dixon, ). Camera trapping can make a positive contribution to conservation and ecological restoration by identifying and quantifying floral visitors, documenting decline in abundance or local extinction, documenting changes in behavior, detecting them in candidate sites for conservation translocations, and/or the detection of possible replacement pollinators.…”

Phytophthora cinnamomi

“…In south-west Western Australia, over 3500 plant species, many of which are endemic, are susceptible to P. cinnamomi. P. cinnamomi is responsible for dramatic changes to the composition of plant communities over vast areas and threatens macrofungal and bird biodiversity in this region (Anderson et al, 2010;Davis et al, 2014). In South Africa, sclerophyllous shrubs in the Agathosma genus are part of the Cape Floral Kingdom, a small region in terms of land area, but an area which has the greatest known species richness (Cowling et al, 1996).…”

Using climate change models to inform the recovery of the western ground parrotPezoporus flaviventris

“…Determining exact numbers is challenging, but there is a consensus amongst researchers and conservation managers that decline is ongoing, and the total population is currently estimated to comprise < 150 individuals (Burbidge et al, 2016). According to Burbidge et al (2016), the drivers of this decline are introduced predators, especially feral cats Felis catus (Doherty et al, 2015), inappropriate fire regimes (Department of Parks and Wildlife, 2014), habitat loss and fragmentation (Hobbs, 2001), and phytophthora dieback (Davis et al, 2014; Phytophthora cinnamomi is a fungal pathogen that kills many of the plant species that provide habitat for the western ground parrot).…”