Micah J. Davies

Dispersal behaviour of Brown Treecreepers predicts functional connectivity for several other woodland birds

Abstract The persistence of native species in fragmented landscapes is dependent on dispersal or foraging movements between habitat patches, which may be limited. Although corridors have been heralded as solutions, their effectiveness depends on species’ movement behaviour, which has rarely been studied. We previously analysed dispersal movements of Brown Treecreepers (Climacteris picumnus), concluding that scattered trees may provide greater connectivity than corridors, and the length of corridors and size of any gaps within may be more important than corridor width. However, conclusions from a single species may not be representative. Here, we analyse dispersal movements of two sedentary birds—Eastern Yellow Robins (Eopsaltria australis) and White-throated Treecreepers (Cormobates leucophaeus)—and foraging movements of two semi-nomadic birds—Fuscous Honeyeaters (Lichenostomus fuscus) and White-plumed Honeyeaters (L. penicillatus). Despite differences in their ecologies and purpose of movements, we found the movement strategies of these species at the local landscape scale were similar. The types of connectivity used and gap distances crossed were similar to those for Brown Treecreepers, strengthening our understanding of how to provide connectivity. We suggest that decision rules for movement have been shaped over evolutionary time by variability in the landscape, so movement behaviour may be less species-specific than previously assumed.

Can farm-management practices reduce the impact of house mouse populations on crops in an irrigated farming system?

The impacts of a range of farm-management practices on house mouse (Mus domesticus) populations were tested in a large replicated field study in a complex irrigated farming system in southern New South Wales, Australia. An advisory panel, made up of farmers, extension officers, industry representatives and scientists developed a series of best-practice farm-management actions to minimise the impact of mice. Twelve experimental sites were split into six treated sites, where farmers were encouraged to conduct the recommended practices, and six untreated sites, where farmers conducted their normal farming practices. Mouse abundance was generally low to moderate for the 4-year project (5–60% adjusted trap success). We found significant reductions in population abundance of mice on treated sites when densities were moderate, but no differences when densities were low. Biomass of weeds and grasses around the perimeter of crops were significantly lower on treated sites because of applications of herbicide sprays and grazing by sheep. We could not detect any significant difference in mouse damage to crops between treated and untreated sites; however, levels of damage were low (<5%). Yields of winter cereals and rice crops were significantly higher on treated sites by up to 40%. An analysis of benefits and costs of conducting farming practices on treated sites compared with untreated sites showed a 2 : 1 benefit to cost ratio for winter cereals, 9 : 1 for rice and 4 : 1 for soybeans.

Does structural connectivity facilitate movement of native species in Australia's fragmented landscapes?: a systematic review protocol

BackgroundHabitat fragmentation and accompanying isolation effects are among the biggest threats to global biodiversity. The goal of restoring connectivity to offset these threats has gained even greater urgency under the looming spectre of climate change. While linear corridors have been the most commonly proposed solution to these issues, it has become increasingly recognised that structural connectivity exists in different forms with a variety of characteristics. We previously conducted a systematic review from 2008-2010 to collate and synthesise evidence regarding the relationship between these different types of structural connectivity and the actual movement of native Australian plants and animals (i.e., functional connectivity). Our previous review produced a number of management recommendations but also identified significant knowledge gaps. Given that empirical research into connectivity has become even more common since the original review and that it has been more than five years since the original literature searches, the time is ripe for an update of that review.MethodsWe will update our previous systematic review by repeating a thorough search for both published and unpublished evidence on the effects of structural connectivity on animal and plant movement through heterogeneous landscapes. We will slightly broaden the scope of the original review by including data on semi-aquatic species as well as terrestrial ones. Studies will be included if they: 1) contain data on a terrestrial or semi-aquatic native Australian species; 2) have at least one study site that contains some form of structural connectivity between otherwise isolated patches of habitat; and 3) include data on movement of species through the connectivity or data that allow inference of movement (or the lack thereof). We will repeat the analyses carried out for the original review which used hierarchical linear modelling to assess the effects of numerous sources of heterogeneity (e.g., type of connectivity, width of connection, ecosystem type, taxonomic group, and many other characteristics of the species, habitat, and connectivity) on the amount of movement observed in a landscape. If increased sample sizes allow we will also carry out additional meta-analyses, which were not possible with the original dataset.

Monitoring of small mammal populations in the Brindabella Ranges after fire

We live-trapped small mammals in the Brindabella Ranges west of Canberra, Australian Capital Territory from April 2009 until October 2011 to assess population recovery after an intense and widespread fire that occurred across the region in 2003. Three native mammals (agile antechinus, Antechinus agilis; dusky antechinus, Antechinus swainsonii; bush rat, Rattus fuscipes) were encountered. Trapping records and spool-and-line movement patterns suggested a strong association of these small mammals with moist gully vegetation that had survived the fire.

Flood regimes driving vegetation and bird community transitions in semiarid floodplain woodlands

Ecohydrology. 2018;11:e1954. https://doi.org/10.1002/eco.1954 Abstract Water resource development in many parts of the world has resulted in serious reductions in the frequency, extent, and duration with which floodplain woodlands are inundated, resulting in significant habitat change and loss of productivity. Yet few studies have attempted to assess the effects of different flood regimes upon floodplain vegetation and fauna communities together, particularly during the terrestrial phase. We use new space‐for‐time substitution data from south‐eastern Australia to describe the nature of Eucalyptus largiflorens floodplain woodland communities under different flood regimes, from which inferences may be made about the consequences of water management decisions. We explore the hypothesis that differences in flood regime drive dissimilarities in vegetation structure and condition as well as variation in woodland bird abundance. Overall, insufficient floodingwas associated with degradation of floodplainwoodland condition and structure, as well as shifts in the relative abundance of key woodland bird groups. The results suggest that changes in flooding frequency are associatedwith significant shifts in site character and ultimately transitions in community composition, even within the same broad vegetation type. Importantly, these transitions are the result of interactions between water availability, vegetation changes, fauna habitat preferences, and interspecific interference competition. In addition, they indicate the influence of altered flood regimes upon terrestrial fauna of floodplain ecosystems rather than just aquatic components—a link that is relatively neglected by both scientists andmanagers to‐date. Such transitions and links have far‐reaching implications for ecosystem function at multiple scales and for how floodplains are understood, valued, and managed.