Search

A thesis submitted in total fulfilment of the requirements for the degree of Doctor of Philosophy to the School of Agriculture, Biomedicine and Environment, La Trobe University, Victoria, Australia.

Human society is presently beset by an array of anthropogenic social-ecological crises that threaten the sustainability of the social-ecological systems that sustain our livelihoods. While research alone will not rectify these issues, it can help to answer key questions that must be addressed to develop effective solutions. To address such questions in a cohesive, compelling manner, social-ecological research can be bounded, structured, and distilled through innumerable organizing principles or theoretical frameworks. For this dissertation, I focused on the geographic region of Tierra del Fuego and sought to draw from the array of disciplines and methods that use sound as a lens for biological, ecological, and/or social inquiry. I also endeavored to consider various temporal, spatial, and organizational scales while investigating a selection of topics with a) specific importance in the social-ecological systems of Tierra del Fuego and b) general relevance to global social-ecological challenges. Chapter 1 provides an introduction to the dissertation, and Chapter 6 serves as a conclusion. The objective of Chapter 2, “Biogeographical and analytical implications of temporal variability in geographically diverse soundscapes”, was to provide some guidance to passive acoustic monitoring (PAM) practitioners on how to design appropriate temporal sampling schemes based on the temporal variability of the sounds one wishes to measure and the power and storage limitations of acoustic recorders. We first quantified the temporal variability of several soundscape measurements and compared that variability across sites and times of day. We also simulated a wide range of temporal sampling schemes in order to model their representativeness relative to continuous sampling. For Chapter 3, “Sentinels for sentinels: passive acoustic and camera trap monitoring of sensitive penguin populations”, we tested the utility of PAM to monitor behavior and abundance of Magellanic (Spheniscus magellanicus) and southern rockhopper penguins (Eudyptes chrysocome) at different spatial and temporal scales. We conducted in situ observations of the acoustic behavior of each species, and we compared acoustic metrics with penguin counts from narrowly focused camera traps and larger-extent observations of colony density. Chapter 4, “Acoustic monitoring shows invasive beavers (Castor canadensis) increase avian diversity in Tierra del Fuego”, is focused on impacts of the invasive North American beaver (Castor canadensis) on Fuegian bird communities. We sought to determine how bird communities might differ between intact riparian forests, beaver ponds, and beaver meadows created by pond drainage. We conducted PAM and classic avian point counts under each of these conditions across seasons to test for differences between impact conditions and to compare the two methodologies. For Chapter 5, “Human-nature connection and soundscape perception: insights from Tierra del Fuego, Argentina”, we evaluated the relationship between soundscape perception and nature relatedness by conducting surveys and soliciting responses to soundscape audio prompts. We also examined the potential for any demographic influences on nature relatedness or soundscape perception in the context of local social tensions.

2019 Annual Forum presentation - overview of the research delivered over the five year EWKR project

The research conducted by the MDB EWKR Waterbird Theme has produced new information to assist managers to better target water, vegetation and waterbird management to ensure ‘event readiness’ at sites between flooding events and to maximise recruitment. Maximising recruitment into the adult population depends on optimising the number of birds that nest, the number of chicks that fledge from each site, and the survival of those birds as juveniles, sub-adults and breeding adults. Information is needed quantifying these variables and what affects them – however the mobility of waterbirds and lack of information on their movements makes this difficult. Therefore, the MDB EWKR Waterbird Theme research activities included: detailed movement and habitat-use studies of individual birds over the duration of the EWKR project using tracking devices (satellite GPS transmitters); motion-sensing and time-lapse camera nest monitoring; on-ground tagged-nest and water depth monitoring; colony mapping; analysis of chick diet and energy sources; and modelling of chick energy requirements.

Appendix A1.1 The influence of flow and non-flow related stressors on the drivers of fish recruitmentAppendix A1.2 Prioritising fish research for flow management in the Murray-Darling BasinAppendix A1.3 Riverscape recruitment: a conceptual synthesis of drivers of fish recruitment in riversAppendix A1.4 Examination of the relationship between food density, temperature and early-life stage growth and survivalAppendix A1.5 Understanding the feeding requirements of larval fish in the northern Murray–Darling BasinAppendix A1.6 Comparison of the thermal and nutritional regimes among main channel and floodplain habitat patchesAppendix A1.7 The relationship between discharge, reach hydraulic complexity, zooplankton production and retention in a lowland river systemAppendix A1.8 Investigating the relationship between flow, structural habitat, hydrodynamics and patterns of larval settlement and retentionAppendix A1.9 Water infrastructure and challenges for fish conservation: A trait-based analysis to foresee fish recruitment in regulated riversAppendix A1.10 Basin-scale population dynamics of Golden Perch and Murray Cod: relating flow to provenance, movement and recruitment in the Murray–Darling BasinAppendix 2: Theme Data InventoryAppendix 3: Theme OutputsAppendix 4: Theme Engagement and Communications Activities

MMCP Collaboration (MMCP) is a project supported by the Joint State Governments and the Murray-Darling Basin Authority to generate and adopt freshwater ecological knowledge through collaboration, to maintain research capability and contribute supporting science to underpin the Basin-Wide Watering Strategy.

MMCP Collaboration (MMCP) is a project supported by the Joint State Governments and the Murray-Darling Basin Authority to generate and adopt freshwater ecological knowledge through collaboration, to maintain research capability and contribute supporting science to underpin the Basin-Wide Watering Strategy.The Fish movement theme is one of five themes that make up MMCP. This project aimed to increase the capacity of training lock staff to tag fish with automated transponders, to increase available data on fish movement. This document outlines the equipment, procedures and handling of data for lock staff to undertake PIT tagging fish after initial training.

Biodiversity loss is the silent crisis of the 21st century. Human activities are drastically altering the diversity of life on Earth, yet the extent of this transformation is shrouded by our limited information on biodiversity and how it is changing. Emerging technologies may be suited to fill this information gap, and as a result increase our capacity to measure and manage natural systems. Acoustic monitoring is a remote sensing technique that is rapidly reshaping the temporal and spatial scales with which we can assess animal biodiversity. Through recording and analyzing soundscapes—the collection of sounds occurring at a given place and time—we can assess biodiversity, habitat condition, and environmental change. However, the relationships between soundscapes and these three ecological dimensions are still in the early phases of categorization, especially in aquatic systems. This dissertation investigates how soundscapes can be used to measure biodiversity, habitat condition, and environmental change in aquatic habitats. It addresses several knowledge gaps: First, I develop a framework for classifying unknown sounds within a soundscape, which I use to measure the acoustic diversity and dynamics within a tropical freshwater wetland. Second, I demonstrate that soundscapes can reflect the resilience of animal communities following disturbance events. Altered soundscapes revealed that Hurricane Maria, which swept through Puerto Rico in September 2017, impacted dry forest animal communities more than adjacent coral reef communities. Third, in kelp forest habitats off the coast of California, USA, I showed that soundscape variables correlated with ecological variables associated with regime shift in kelp forests, including urchin density, kelp cover, and fish diversity. Overall, this dissertation demonstrates that soundscape recording and analysis is a promising way to assess the ecological conditions of aquatic systems.

The MDB EWKR Fish Theme focussed on fish recruitment and sought to improve our understanding of the key drivers, functional processes and limitations of successful recruitment of native fish. This would lead to an improved capacity to predict fish recruitment outcomes in response to different environmental water parameters. In summary, our research demonstrates that both fish population processes, and the key drivers that support recruitment operate at multiple spatial scales, from the patch to the basin scale. Food production areas coupled with appropriate temperature regimes, and the ability for larval dispersal or retention at patch to segment scales, were found to be important drivers of recruitment success. Hydraulic diversity is integral to providing appropriate conditions for food production and dispersal/retention of early-life stages. Connectivity at small to large scales is also critical in enabling access to appropriate habits and dispersal to maintain populations at catchment to basin scales. Our research also demonstrated that under droughtconditions, additional factors such as abundance and condition of adults, and maintenance of refuge areas are likely to be playing a critical role in determining recruitment success.