School of Science - Te Kura Pūtaiao
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Research at AUT's School of Science - Te Kura Pūtaiao is focused on key scientific issues with regional and global significance. The common theme connecting all research areas is sustainability – in the broadest sense as it relates to environmental and human health. Our research is closely allied to teaching and learning opportunities at undergraduate and postgraduate level within the school.
Research is organised in five main areas:
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Browsing School of Science - Te Kura Pūtaiao by Subject "0602 Ecology"
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- ItemAre Rare Plant Species Less Resistant Than Common Ones to Herbivores? A Multi-plant Species Study Using Above- and Below-Ground Generalist Herbivores(Wiley, 2023-09-05) Bürli, S; Ensslin, A; Kempel, A; Fischer, MRare plant species are suggested to be less resistant to herbivores than common species. Their lower apparency and the fact that they often live in isolated populations, resulting in fewer herbivore encounters, might have led to the evolution of reduced defences. Moreover, their frequent lower levels of genetic diversity compared with common species could negatively affect their resistance against enemies. However, the hypothesis that plant resistance depends on plant regional and local rarity, independently of habitat and competitive and growth strategy, lacks evidence. To test this hypothesis, we assessed the performance and preference of one belowground and three aboveground generalist invertebrate herbivores from different taxonomic groups as indicators of plant resistance. Herbivores were fed a total of 62 regionally and locally rare and common plant species from Switzerland. We accounted for differences in a plant's growth and competitive strategy and habitat resource availability. We found that regionally and locally rare and common plant species did not generally differ in their resistance to most generalist herbivores. However, one herbivore species even performed better and preferred locally and regionally common plant species over rarer ones, indicating that common species are not more resistant, but tend to be less resistant. We also found that all herbivore species consistently performed better on competitive and large plant species, although different herbivore species generally preferred and performed better on different plant species. The latter indicates that the use of generalist herbivores as indicators of plant-resistance levels can be misleading. Synthesis: Our results show that rare plant species are not inherently less resistant than common ones to herbivores. Instead, our results suggest that the ability of plants to allocate resources away from defence towards enhancing their competitive ability might have allowed plants to tolerate herbivory, and to become locally and regionally common.
- ItemBioluminescence in Cephalopods: Biodiversity, Biogeography and Research Trends(Frontiers Media SA, 2023-06-27) Otjacques, E; Pissarra, V; Bolstad, K; Xavier, JC; McFall-Ngai, M; Rosa, RNumerous terrestrial and marine organisms, including cephalopods, are capable of light emission. In addition to communication, bioluminescence is used for attraction and defense mechanisms. The present review aims to: (i) present updated information on the taxonomic diversity of luminous cephalopods and morphological features, (ii) describe large-scale biogeographic patterns, and (iii) show the research trends over the last 50 years on cephalopod bioluminescence. According to our database (834 species), 32% of all known cephalopod species can emit light, including oegopsid and myopsid squids, sepiolids, octopuses, and representatives of several other smaller orders (bathyteuthids, and the monotypic vampire “squid”, Vampyroteuthis infernalis and ram’s horn “squid”, Spirula spirula). Most species have a combination of photophores present in different locations, of which light organs on the head region are dominant, followed by photophores associated with the arms and tentacles and internal photophores. Regarding the biogeographic patterns of cephalopod species with light organs, the most diverse ocean is the Pacific Ocean, followed by the Atlantic and Indian Oceans. The least diverse are the Southern and the Arctic Oceans. Regarding publication trends, our systematic review revealed that, between 1971 and 2020, 277 peer-reviewed studies were published on bioluminescent cephalopods. Most research has been done on a single species, the Hawaiian bobtail squid Euprymna scolopes. The interest in this species is mostly due to its species-specific symbiotic relationship with the bacterium Vibrio fischeri, which is used as a model for the study of Eukaryote–Prokaryote symbiosis. Because there are many knowledge gaps about the biology and biogeography of light-producing cephalopods, new state-of-the-art techniques (e.g., eDNA for diversity research and monitoring) can help achieve a finer resolution on species’ distributions. Moreover, knowledge on the effects of climate change stressors on the bioluminescent processes is nonexistent. Future studies are needed to assess such impacts at different levels of biological organization, to describe the potential broad-scale biogeographic changes, and understand the implications for food web dynamics.
- ItemCombining Multiple Stable Isotope Methods Elucidates Diet, Trophic Position and Foraging Areas of Southern Ocean Humpback Whales Megaptera novaeangliae(Inter-Research Science Center, 2024) Bury, SJ; Peters, KJ; Sabadel, AJM; St. John Glew, K; Trueman, C; Wunder, MB; Cobain, MRD; Schmitt, N; Donnelly, D; Magozzi, S; Owen, K; Brown, JCS; Escobar-Flores, P; Constantine, R; O’Driscoll, RL; Double, M; Gales, N; Childerhouse, S; Pinkerton, MHSouthern Ocean humpback whales Megaptera novaeangliae are capital breeders, breeding in the warm tropics/subtropics in the winter and migrating to nutrient-rich Antarctic feeding grounds in the summer. The classic feeding model is for the species to fast while migrating and breeding, surviving on blubber energy stores. Whilst northern hemisphere humpback whales are generalists, southern hemisphere counterparts are perceived as krill specialists, but for many populations, uncertainties remain regarding their diet and preferred feeding locations. This study used bulk and compound-specific stable isotope analyses and isoscape-based feeding location assignments to assess the diet, trophic ecology and likely feeding areas of humpback whales sampled in the Ross Sea region and around the Balleny Islands. Sampled whales had a mixed diet of plankton, krill and fish, similar to the diet of northern hemisphere humpback whales. Proportions of fish consumed varied but were often high (2-60%), thus challenging the widely held paradigm of Southern Ocean humpback whales being exclusive krill feeders. These whales had lower 15N values and trophic position estimates than their northern hemisphere counterparts, likely due to lower Southern Ocean baseline 15N surface water values and a lower percentage consumption of fish, respectively. Most whales fed in the Ross Sea shelf/slope and Balleny Islands high-productivity regions, but some isotopically distinct whales (mostly males) fed at higher trophic levels either around the Balleny Islands and frontal upwelling areas to the north, or en route to Antarctica in temperate waters off southern Australia and New Zealand. These results support other observations of humpback whales feeding during migration, highlighting the species’ dietary plasticity, which may increase their foraging and breeding success and provide them with greater resilience to anthropogenically mediated ecological change. This study highlights the importance of combining in situ field data with regional-scale isoscapes to reliably assess trophic structure and animal feeding locations, and to better inform ecosystem conservation and management of marine protected areas.
- ItemGeometric Implications of Photodiode Arrays on Received Power Distribution in Mobile Underwater Optical Wireless Communication(MDPI AG, 2024-05-28) Govinda Waduge, Tharuka; Seet, Boon-Chong; Vopel, KayUnderwater optical wireless communication (UOWC) has gained interest in recent years with the introduction of autonomous and remotely operated mobile systems in blue economic ventures such as offshore food production and energy generation. Here, we devised a model for estimating the received power distribution of diffused line-of-sight mobile optical links, accommodating irregular intensity distributions beyond the beam-spread angle of the emitter. We then used this model to conduct a spatial analysis investigating the parametric influence of the placement, orientation, and angular spread of photodiodes in array-based receivers on the mobile UOWC links in different Jerlov seawater types. It revealed that flat arrays were best for links where strict alignment could be maintained, whereas curved arrays performed better spatially but were not always optimal. Furthermore, utilizing two or more spectrally distinct wavelengths and more bandwidth-efficient modulation may be preferred for received-signal intensity-based localization and improving link range in clearer oceans, respectively. Considering the geometric implications of the array of receiver photodiodes for mobile UOWCs, we recommend the use of dynamically shape-shifting array geometries.
- ItemPredicting Ecological Change in Tussock Grasslands of Aotearoa New Zealand(New Zealand Ecological Society, 2023-11-10) Day, Nicola; Barratt, Barbara; Christensen, Brendon; Curran, Timothy; Dickinson, Katharine; Lavorel, Sandra; Norton, David; Buckley, HannahNatural grasslands are among the most threatened biomes on Earth. They are under pressure from land cover change including afforestation, farming intensification, invasive species, altered fire regimes, and soil amendments, all of which impact native biodiversity and ecosystem functioning. In Aotearoa New Zealand, tussock-dominated native grasslands expanded due to increased fire activity during waves of human settlement. These areas have subsequently been maintained as modified grasslands by agricultural pastoral land management practices and effects of introduced feral mammals. Despite many decades of research on biodiversity in tussock grasslands, we need greater fundamental understanding of many processes causing change in their biodiversity and ecosystem functioning in order to predict how future global change will impact this important and increasingly threatened biome. In this perspective forum article, we present five key research questions that, if answered, would greatly enhance our understanding of connections between tussock grassland biodiversity, ecosystem functioning, and associated ecosystem services: (1) What are the relative impacts of domesticated and non-domesticated mammals on indigenous biodiversity in grasslands? (2) Where will invasive plants undergo range expansion? (3) Will future fires tip tussock grasslands into alternative vegetation states? (4) What are the implications of woody thickening by native or non-native species? (5) What are the impacts of global change, and vegetation change in particular, on soil processes and ecosystem functioning? We provide recommendations for research to address and integrate across these questions using both existing and new data. This work would build on our current knowledge and lead to a framework to better understand the ecological impacts of ongoing global change in tussock grasslands.
- ItemPriorities for Synthesis Research in Ecology and Environmental Science(Wiley, 2023-01-11) Halpern, Benjamin S; Boettiger, Carl; Dietze, Michael C; Gephart, Jessica A; Gonzalez, Patrick; Grimm, Nancy B; Groffman, Peter M; Gurevitch, Jessica; Hobbie, Sarah E; Komatsu, Kimberly J; Kroeker, Kristy J; Lahr, Heather J; Lodge, David M; Lortie, Christopher J; Lowndes, Julie SS; Micheli, Fiorenza; Possingham, Hugh P; Ruckelshaus, Mary H; Scarborough, Courtney; Wood, Chelsea L; Wu, Grace C; Aoyama, Lina; Arroyo, Eva E; Bahlai, Christie A; Beller, Erin E; Blake, Rachael E; Bork, Karrigan S; Branch, Trevor A; Brown, Norah EM; Brun, Julien; Bruna, Emilio M; Buckley, Lauren B; Burnett, Jessica L; Castorani, Max CN; Cheng, Samantha H; Cohen, Sarah C; Couture, Jessica L; Crowder, Larry B; Dee, Laura E; Dias, Arildo S; Diaz‐Maroto, Ignacio J; Downs, Martha R; Dudney, Joan C; Ellis, Erle C; Emery, Kyle A; Eurich, Jacob G; Ferriss, Bridget E; Fredston, Alexa; Furukawa, Hikaru; Gagné, Sara A; Garlick, Sarah R; Garroway, Colin J; Gaynor, Kaitlyn M; González, Angélica L; Grames, Eliza M; Guy‐Haim, Tamar; Hackett, Ed; Hallett, Lauren M; Harms, Tamara K; Haulsee, Danielle E; Haynes, Kyle J; Hazen, Elliott L; Jarvis, Rebecca M; Jones, Kristal; Kandlikar, Gaurav S; Kincaid, Dustin W; Knope, Matthew L; Koirala, Anil; Kolasa, Jurek; Kominoski, John S; Koricheva, Julia; Lancaster, Lesley T; Lawlor, Jake A; Lowman, Heili E; Muller‐Karger, Frank E; Norman, Kari EA; Nourn, Nan; O'Hara, Casey C; Ou, Suzanne X; Padilla‐Gamino, Jacqueline L; Pappalardo, Paula; Peek, Ryan A; Pelletier, Dominique; Plont, Stephen; Ponisio, Lauren C; Portales‐Reyes, Cristina; Provete, Diogo B; Raes, Eric J; Ramirez‐Reyes, Carlos; Ramos, Irene; Record, Sydne; Richardson, Anthony J; Salguero‐Gómez, Roberto; Satterthwaite, Erin V; Schmidt, Chloé; Schwartz, Aaron J; See, Craig R; Shea, Brendan D; Smith, Rachel S; Sokol, Eric R; Solomon, Christopher T; Spanbauer, Trisha; Stefanoudis, Paris V; Sterner, Beckett W; Sudbrack, Vitor; Tonkin, Jonathan D; Townes, Ashley R; Valle, Mireia; Walter, Jonathan A; Wheeler, Kathryn I; Wieder, William R; Williams, David R; Winter, Marten; Winterova, Barbora; Woodall, Lucy C; Wymore, Adam S; Youngflesh, CaseySynthesis research in ecology and environmental science improves understanding, advances theory, identifies research priorities, and supports management strategies by linking data, ideas, and tools. Accelerating environmental challenges increases the need to focus synthesis science on the most pressing questions. To leverage input from the broader research community, we convened a virtual workshop with participants from many countries and disciplines to examine how and where synthesis can address key questions and themes in ecology and environmental science in the coming decade. Seven priority research topics emerged: (1) diversity, equity, inclusion, and justice (DEIJ), (2) human and natural systems, (3) actionable and use-inspired science, (4) scale, (5) generality, (6) complexity and resilience, and (7) predictability. Additionally, two issues regarding the general practice of synthesis emerged: the need for increased participant diversity and inclusive research practices; and increased and improved data flow, access, and skill-building. These topics and practices provide a strategic vision for future synthesis in ecology and environmental science.
- ItemRarity and Life-History Strategies Shape Inbreeding and Outbreeding Effects on Early Plant Fitness(Elsevier BV, 2024-10) Bürli, Sarah; Ensslin, Andreas; Fischer, MarkusLocal abundance and regional distribution are two aspects of a species’ rarity. They are suggested to differentially alter genetic processes in plants: Locally rare species are hypothesized to suffer less from inbreeding and outbreeding than locally common species, thanks to genetic purging through long inbreeding histories and weaker local adaptations, respectively. Regionally rare species are hypothesized to be more susceptible to outbreeding, but less to inbreeding, compared to regionally common ones, due to small and declining range size. While this has major implications for plant conservation practices, we lack evidences and general understanding on how breeding effects on a plant’s early life fitness are related to its local and regional rarity. To investigate effects of inbreeding and outbreeding on plants’ early fitness, we performed self-, within- and between-population pollinations in eight pairs of closely related species differing in regional and local rarity. To avoid biases due to context dependency, we took species competitive ability, habitat resource-richness and resource-allocation strategy into account in the analyses. We then tested how inbreeding and outbreeding affected five fruit-, seed- and seedling-related traits. Inbreeding did not generally have more negative effects on early fitness of regionally rare and non-competitive species than on regionally common and competitive ones. Outbreeding was generally beneficial to early fitness of plant species across the gradients of regional rarity, competitive ability and habitat resource-richness. Our results show that outbreeding may be beneficial to the early fitness of plant species, including rare and non-competitive ones and may be considered for conservation strategies.