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Research Questions/Objectives:
Questions:
Objective:
Brief Description of the Project:
Project Phases:
Background and Significance of the Research Question to drought risk, vulnerability, preparedness, or resilience:
Pasture and Crop Drought Resistance:
It has been clearly demonstrated that the capacity for ecosystems to resist change or to recover from disturbances such as drought is dependent on biodiversity. Hence, promoting biodiversity in agricultural systems is expected to promote drought resistance. Furthermore, studies have also found that contradictory to the common notion that only one or two drought resistant species are responsible for the ability of a system to cope in drought conditions, research indicates the presence of most if not all species has an effect on increasing the drought resistance of an ecosystem 3,4.
Governments and NGOs are developing financial incentives to encourage farmers to adopt measures that will increase farm diversity. Yet, there are no methods in place to accurately assessing biodiversity, especially metrics which focus on species that will influence the ecosystem function. The development of effectual sensor/s that can quantify the biodiversity of an agricultural system with relatively low expertise, i.e., you don’t have to be a trained entomologist to use it, would be of great help to farmers in diagnosing if their changes in behaviour was actually influencing biodiversity. As agriculture moves towards a mentality of “smart” farming these sensors may also be integrated into their systems to increase their efficiency in relation to other practises on the farm such as when is the best time to fertilise or spray insecticide based on long term monitoring of trends in population dynamics which may be indicative of corresponding conditions.
Direct Economic Benefits for Farmers:
Provide a buffer for the economic impacts of drought by diversifying the income of farmers through:
Possible Alternative Outcomes of the Study (Pest Management):
Drought conditions can increase insect herbivory as a result of diminished defence in plants5. This effect can compound the impact of droughts on crop species6. An invertebrate sensor arrays may aid in effective pest management by helping to identify when there is a sufficient population of a pest’s species to precipitate an outbreak and or identify the guild/species that is likely to be problematic allowing for more targeted eradication. Sensors may also show the conditions that are ideal for control measures to be implemented whilst mitigating negative effects to pollinators and other invertebrates that have a positive effect on agriculture such as species that are natural predators of pest species. This may also lead to a dramatic reduction of the amount of spraying that is required to produce similar results to the methodologies currently being employed and reduce the impacts of spraying on biodiversity, further increasing drought resistance.
Academic and research experience relevant to the honours project:
Whilst completing my Bachelor of Science I completed courses relevant to this research project including (Tropical Entomology, Sensors and Sensing for Scientists, Technological Applications in Ecology, and Ecological Research Methods) with a final overall grade point average of 6.16.
I have worked in the field for the past year as a graduate environmental scientist for a well renowned consultancy Biotropica Australia PTY LTD (Biotropica), working with a small team of dedicated scientists and further developing my analytical skills in a wide variety of fields of study including population dynamics, remote sensing for the purposes of bat and ground mammal detection, water quality monitoring, invasive fauna and flora, protected flora and fauna, and geographic information systems. I have also endeavoured to further develop my professional and communication skills.
During my time at Biotropica I have been assisting on the “Three Corridors Research Project”. A multi-disciplinary project with the goal of quantifying the effectiveness of three revegetated and regrowth habitat corridors on the Atherton tablelands in promoting connectivity and increasing biodiversity in the national parks which they connect. My involvement has included the deployment of remote audio bat detectors the deployment of camera traps, assisting in the completion of vegetation transects, species identification based on camera trap data, data analysis both of past data from initial surveys done directly after the corridors were planted twenty years ago and the data that is currently being produced by the research.
I am a highly motivated and resourceful individual who is very interested in the field of sustainable agriculture and applying/improving my understanding of ecological systems to improve both best practise, financial outcomes for farmers and long-term outcomes for the environment. I believe this is one of the great contributions that we as scientists can make to leave our world in better condition for the next generation.
Principal Supervisor’s skills and experience in relation to this project topic:
Professor Susan Laurance is a tropical ecologist at JCU who studies that effects of land use and climate change on biodiversity and tropical ecosystems. Laurance has >25 years of experience in quantifying the community structure and composition of taxa including: vegetation, invertebrates, birds, and mammals. She is a very experience research scientist with >150 peer-reviewed publications.
Prof Laurance has collected and worked with large sensor arrays as part of her Daintree Drought Experiment which has been running for > 5 years. She does not have experience in insect sensor detection but Dr Peter Yeeles, an invertebrate ecologist who is currently working on yellow crazy ant detection with sensors will be the project’s secondary supervisor.
Professor Laurance is a very experienced supervisor and has supervised a wide variety of PhD, Masters and Honours projects varying from “Using mosquito excreta to enhance mosquito-borne disease surveillance” to “Rainforest plant flammability and recovery post-fire”.
Professor Laurance’s experience both in experimental design and in managing large scale collaborative projects will be invaluable, as this project will require the engagement in expertise from a variety of fields of research including, entomology, acoustic and visual sensor design, and community ecology.
References:
1. Kirkeby, C., Rydhmer, K., Cook, S.M., Strand, A., Torrance, M.T., Swain, J.L., Prangsma, J., Johnen, A., Jensen, M., Brydegaard, M. & Græsbøll, K. (2021). Advances in automatic identification of flying insects using optical sensors and machine learning. Sci Rep. 11(1555). https://doi.org/10.1038/s41598-021-81005-0
2. Yang, Y., Liu, W., Xing, K., Qiao, J., Wang, X., Gao, L. & Shen, Z. (2010). Research on insect identification based on pattern recognition technology. 2010 Sixth International Conference on Natural Computation. pp.545-548. 10.1109/ICNC.2010.5583156
3. Tilman, D. & Downing, J. (1994) Biodiversity and stability in grasslands. Nature. 367. pp.363–365. https://doi.org/10.1038/367363a0
4. Wright, A. J., Mommer, L., Barry, K. & Van Ruijven, J. (2021). Stress gradients and biodiversity: monoculture vulnerability drives stronger biodiversity effects during drought years. Ecology. 102(1). pp.e03193. https://doi.org/10.1002/ecy.3193
5. Gely, C., Laurance, S.G. & Stork, N.E. (2020). How do herbivorous insects respond to drought stress in trees?. Biological Reviews. 95(2). pp.434-448. https://doi.org/10.1111/brv.12571
6. Grinnan, R., Carter, T.E. & Johnson, M.T.J. (2013). Effects of drought, temperature, herbivory, and genotype on plant–insect interactions in soybean (Glycine max). Arthropod-Plant Interactions. 7. pp.201–215. https://doi.org/10.1007/s11829-012-9234-z
Ecosystem functions play a crucial role in sustaining environments worldwide, including those heavily influenced by human activities. These functions encompass vital processes such as air and water purification, climate regulation, nutrient cycling, crop pollination, seed dispersal, and the provision of habitats for diverse species (Alberti 2005). Preserving the delicate balance of these functions is essential for ecological resilience and the long-term health of our planet(Srivastava & Vellend 2005).
In the aftermath of extreme weather events like droughts, the absence of essential ecosystem functions can significantly impede recovery processes (Loeser, Sisk & Crews 2007; Souther et al. 2020). For instance, vegetation cover plays a key role in slowing water movement and enhancing soil infiltration capacity and decreasing soil erosion, critical for ecological resilience to droughts (Zuazo & Pleguezuelo 2009). Decreased vegetation cover before a drought can have significant implications for the ability of rangelands to support grazing and recover from drought.
Recognizing and restoring ecosystem functions are crucial for enhancing the resilience of grazing systems, especially considering the increasing intensity and frequency of droughts associated with climate change (Chiang, Mazdiyasni & AghaKouchak 2021).
There are concerns about the ecological consequences of cattle grazing practices in savanna rangeland ecosystems, including potential impacts on flora, fauna, and their associated ecosystem functions. To address this, I conducted a study examining the effects of increased cattle grazing intensity on ant communities and one of their ecosystem functions—seed dispersal—at Wambiana Station, Queensland, within a long-term grazing experiment. The focus was on Acacia holosericea, a native species in this ecosystem, using both traditional seed removal experiments and a novel sensor-based method.
Results revealed an increase in ant abundance with higher cattle grazing intensity, although no significant changes in ant community structure were observed (Fig 1) excluding a marginal increase in the total abundance of ants as well as the abundance of a single Iridomyrmex morphospecies in the high intensity grazing treatment. The rapidity of seed removal was higher in the lower grazing intensity treatment compared to the higher intensity treatment (Fig 2). Increased grazing pressure seemed to influence ant foraging behaviour, possibly due to the abundance increase of a dominant (King, Andersen & Cutter 1998) Iridomyrmex morphospecies, affecting the seed removal of Acacia holosericea seeds by the important seed removing genera Rhytidoponera (Gove, Majer & Dunn 2007). While the novel sensor-based method showed some limitations compared to traditional methods, such as a higher failure rate, it provided greater temporal resolution and required less deployment time.
This study underscores the impact of cattle grazing on ecosystem functions, even in the absence of observed changes in community structure. It suggests that direct measurement of ecosystem functions, facilitated by emerging sensor technologies, may be more applicable in a prescriptive setting compared to focusing solely on biological indicators, such as ants. Largely due to direct ecosystem function measurements requiring less time and expertise.
References:
Alberti, M 2005, ‘The effects of urban patterns on ecosystem function’, International regional science review, vol. 28, no. 2, pp. 168-92.
Chiang, F, Mazdiyasni, O & AghaKouchak, A 2021, ‘Evidence of anthropogenic impacts on global drought frequency, duration, and intensity’, Nature communications, vol. 12, no. 1, p. 2754.
Gove, AD, Majer, JD & Dunn, RR 2007, ‘A keystone ant species promotes seed dispersal in a “diffuse” mutualism’, Oecologia, vol. 153, pp. 687-97.
King, JR, Andersen, AN & Cutter, AD 1998, ‘Ants as bioindicators of habitat disturbance: validation of the functional group model for Australia’s humid tropics’, Biodiversity & Conservation, vol. 7, pp. 1627-38.
Loeser, MR, Sisk, TD & Crews, TE 2007, ‘Impact of grazing intensity during drought in an Arizona grassland’, Conservation Biology, vol. 21, no. 1, pp. 87-97.
Souther, S, Loeser, M, Crews, TE & Sisk, T 2020, ‘Drought exacerbates negative consequences of high‐intensity cattle grazing in a semiarid grassland’, Ecological Applications, vol. 30, no. 3, p. e02048.
Srivastava, DS & Vellend, M 2005, ‘Biodiversity-ecosystem function research: is it relevant to conservation?’, Annu. Rev. Ecol. Evol. Syst., vol. 36, pp. 267-94.
Zuazo, VcHD & Pleguezuelo, CRoR 2009, ‘Soil-erosion and runoff prevention by plant covers: a review’, Sustainable agriculture, pp. 785-811.
Overview of Identified Practical Applications:
Monitoring seed removal provides valuable insights into the functioning of ecosystems within grazing systems. Seed removal serves as a practical indicator of ecological processes, particularly in understanding the dynamics of plant-animal interactions (Archer & Pyke 1991). In a grazing system, the assessment of acacia seed removal offers a direct measurement of seed dispersal (Martínez-Bauer et al. 2015; Zelikova & Breed 2008), a critical ecological function that influences plant population dynamics and community composition(Zelikova & Breed 2008). By studying the impact of grazing intensity on seed removal, we can unravel the intricate relationships between herbivores, such as cattle, and seed-dispersing ants. This information can be applied in assessing how grazing practices may affect the establishment and distribution of plant species. Furthermore, the application of seed removal as a monitoring tool contributes to the evaluation of ecosystem resilience (Elmqvist et al. 2003), aiding in the development of sustainable grazing management strategies that consider both plant regeneration and the maintenance of biodiversity within these dynamic ecosystems. Our results support the hypothesis that this important ecosystem function is inhibited by increased grazing pressure at Wambiana. The decrease in the rate of seed removal with increased grazing may have resulted from an increase in the abundance of a single dominant morphospecies altering the behaviour of important seed removal ants which was found in the study of the ant community present.
Ants play a crucial role in grazing agroecosystems, contributing significantly to the overall health and functionality of these ecosystems. These industrious insects serve as essential biological agents by engaging in a variety of activities that positively impact soil structure (Bottinelli et al. 2015), nutrient cycling (Frouz, Jílková & Sorvari 2016), and pest control (Anjos et al. 2022). Ants are proficient soil engineers, creating intricate underground tunnels that enhance soil aeration and water infiltration, ultimately promoting optimal conditions for plant growth (Frouz & Jilková 2008). Their foraging behaviour aids in the breakdown of organic matter, facilitating nutrient release and absorption by plants (Frouz, Jílková & Sorvari 2016). In terms of pest management, ants act as natural predators, preying on various insect pests that may otherwise harm crops and productive grasses (Anjos et al. 2022). This biological control reduces the reliance on chemical pesticides, fostering a more sustainable and environmentally friendly approach to agriculture. In essence, ants play a multifaceted role in grazing agroecosystems, contributing to their resilience and overall productivity. Ants are also ideal as biological indicators of ecosystem health due to there high abundance, ease of capture, relative ease of identification, and known interactions with other organisms (Eldridge et al. 2020; Ohwada & Yamawo 2021). Ants are already being used as biological indicators in grazing systems, mine reclamation projects and various other settings (Delabie et al. 2009; Majer 1983; Peck, Mcquaid & Campbell 1998; Tibcherani et al. 2018).
Seed removal serves as an important indicator of restoration success, encapsulating the intricate dynamics within ecosystems (Lomov, Keith & Hochuli 2009). As a fundamental ecological process, the removal of seeds by various fauna reflects the return of biodiversity and functional relationships in rehabilitated areas (Jordano et al. 2011). Successful restoration efforts aim to recreate not just the physical structure of ecosystems but also the intricate ecological interactions that sustain them (Crouzeilles et al. 2016). By examining seed removal, we can gauge the effectiveness of habitat reconstruction and the resurgence of critical species interactions, such as seed dispersal by animals. This metric not only unveils the resilience of plant communities but also sheds light on the revitalization of ecological services, emphasizing the interconnectedness of flora and fauna in restored environments. As such, seed removal stands as a tangible and dynamic measure of the holistic health and viability of restored ecosystems, providing invaluable insights into the overall success of conservation and restoration initiatives. The field testing of the seed removal sensor that is being developed by Prof. Will Edwards and team at JCU Cairns Campus during my project is a direct contribution to the improvement and development of a widely applicable methodology for measuring seed removal not just by ants, but by mammals and birds as well.
References:
Anjos, DV, Tena, A, Viana-Junior, AB, Carvalho, RL, Torezan-Silingardi, H, Del-Claro, K & Perfecto, I 2022, ‘The effects of ants on pest control: a meta-analysis’, Proceedings of the Royal Society B, vol. 289, no. 1981, p. 20221316.
Archer, S & Pyke, DA 1991, ‘Plant-animal interactions affecting plant establishment and persistence on revegetated rangeland’, Rangeland Ecology & Management/Journal of Range Management Archives, vol. 44, no. 6, pp. 558-65.
Bottinelli, N, Jouquet, P, Capowiez, Y, Podwojewski, P, Grimaldi, M & Peng, X 2015, ‘Why is the influence of soil macrofauna on soil structure only considered by soil ecologists?’, Soil and Tillage Research, vol. 146, pp. 118-24.
Crouzeilles, R, Curran, M, Ferreira, MS, Lindenmayer, DB, Grelle, CE & Rey Benayas, JM 2016, ‘A global meta-analysis on the ecological drivers of forest restoration success’, Nature communications, vol. 7, no. 1, p. 11666.
Delabie, JH, Céréghino, R, Groc, S, Dejean, A, Gibernau, M, Corbara, B & Dejean, A 2009, ‘Ants as biological indicators of Wayana Amerindian land use in French Guiana’, Comptes rendus biologies, vol. 332, no. 7, pp. 673-84.
Eldridge, DJ, Oliver, I, Val, J, Travers, SK & Delgado-Baquerizo, M 2020, ‘Grazing and aridity have contrasting effects on the functional and taxonomic diversity of ants’, Basic and applied ecology, vol. 48, pp. 73-82.
Elmqvist, T, Folke, C, Nyström, M, Peterson, G, Bengtsson, J, Walker, B & Norberg, J 2003, ‘Response diversity, ecosystem change, and resilience’, Frontiers in Ecology and the Environment, vol. 1, no. 9, pp. 488-94.
Frouz, J & Jilková, V 2008, ‘The effect of ants on soil properties and processes (Hymenoptera: Formicidae)’, Myrmecological News, vol. 11, no. 11, pp. 191-9.
Frouz, J, Jílková, V & Sorvari, J 2016, ‘9 r Contribution of wood ants to nutrient cycling and ecosystem function’, Wood ant ecology and conservation, p. 207.
Jordano, P, Forget, P-M, Lambert, JE, Böhning-Gaese, K, Traveset, A & Wright, SJ 2011, Frugivores and seed dispersal: mechanisms and consequences for biodiversity of a key ecological interaction, The Royal Society.
Lomov, B, Keith, DA & Hochuli, DF 2009, ‘Linking ecological function to species composition in ecological restoration: Seed removal by ants in recreated woodland’, Austral ecology, vol. 34, no. 7, pp. 751-60.
Majer, J 1983, ‘Ants: bio-indicators of minesite rehabilitation, land-use, and land conservation’, Environmental management, vol. 7, pp. 375-83.
Martínez-Bauer, AE, Martínez, GC, Murphy, DJ & Burd, M 2015, ‘Multitasking in a plant–ant interaction: how does Acacia myrtifolia manage both ants and pollinators?’, Oecologia, vol. 178, pp. 461-71.
Ohwada, K & Yamawo, A 2021, ‘Functional roles of ants in a temperate grassland’, The Science of Nature, vol. 108, no. 6, p. 56.
Peck, SL, Mcquaid, B & Campbell, CL 1998, ‘Using ant species (Hymenoptera: Formicidae) as a biological indicator of agroecosystem condition’, Environmental Entomology, vol. 27, no. 5, pp. 1102-10.
Tibcherani, M, Nacagava, VAF, Aranda, R & Mello, RL 2018, ‘Review of ants (Hymenoptera: Formicidae) as bioindicators in the Brazilian Savanna’, Sociobiology, vol. 65, no. 2, pp. 112-29.
Zelikova, TJ & Breed, MD 2008, ‘Effects of habitat disturbance on ant community composition and seed dispersal by ants in a tropical dry forest in Costa Rica’, Journal of Tropical Ecology, vol. 24, no. 3, pp. 309-16.
