My Marsden Fund proposal success was reported this week in our local paper, the Otago Daily Times, along with the success of two of my office colleagues. Our office houses researchers from both Manaaki Whenua – Landcare Research and GNS Science, both Crown Research Institutes, and winning three funding bids is quite the success rate for a research staff of about 20!
I’m very excited to announce the success of my project proposal to the Marsden Fund of the NZ Royal Society, entitled Friends on the forest floor: do facilitative interactions dominate in New Zealand’s unique bryoflora? I’ll be working with Associate Professor David Burritt of the University of Otago and Dr. David Glenny of Manaaki Whenua – Landcare Research to explore species interactions and physiological stress in NZ bryophytes over the next 3 years. Here is a summary of this Marsden Fast-Start project:
Competitive species interactions underpin modern theory on how plant communities are structured and which species are present. Facilitation, where the presence of a neighbouring species benefits rather than hinders a plant’s growth, is considered important mainly in harsh environments, where the neighbour could ameliorate the impact of stressful conditions. Bryophytes (mosses and liverworts) are the oldest land plants. They lack roots and internal transport vessels, making them fundamentally different from flowering plants. Because bryophytes obtain nutrients and water directly from the atmosphere, they may be more likely to share than compete for resources, and thus may be especially reliant on facilitation between species to acquire and maintain water in their cells. To determine whether facilitative interactions increase in strength under stressful conditions or occur along the entire environmental gradient, we will measure the stress and performance responses of bryophytes grown in monoculture and with other species along experimentally-imposed temperature and moisture gradients. This will allow us to test the generality of current ecological theory derived from studies of flowering plants.
Yesterday I had the sincere pleasure of being a guest on the Otago Access Radio show Kā manu o Rēhua me Dr. Anderson with Georgia and Tumai, Year 6 tauira from Te Kura Kaupapa Māori o Ōtepoti, and my colleague from Landcare Research Manaaki Whenua, Barbara Anderson. The students and I had a great time discussing my job as a plant ecologist, and some of the crazy and amazing things ecologists do when we set up and run field experiments to answer questions about the natural world.
The podcast version of yesterday’s show should be up soon, but in the meantime you can check out all the great interviews conducted by several students from TKKM o Ōtepoti in previous shows. A few of these students will head to Toronto at the end of July to attend the World Indigenous People’s Conference on Education, and present on their work with the Ahi Pepe Mothnet project that is bringing science experiments directly into schools. To help support the students travelling to the conference, you can donate at their Givealittle page until Friday, 30 June!
In my post-doc work on how colonisation and diversification of plant lineages can have a legacy effect on extant plant communities, we previously showed that understanding evolutionary priority effects is necessary to predict the structure and function of pristine ecological communities. In a paper just published in New Phytologist, we tested whether anthropogenically-driven changes in available habitat and mass immigration (i.e. non-native invasion) eliminate the role of evolutionary priority effects in community assembly. We advanced the theory that radiating lineages can monopolize niche space by showing that evolutionary drivers of community assembly also operate in new habitat created by anthropogenic disturbance. However, we also demonstrated that non-native invasion can erase the otherwise strong role of evolutionary priority effects in shaping native community composition. This work is important and timely because it indicates that effects of human-induced global change on community assembly extend beyond purely ecological dynamics to the ecological consequences of plant radiations.
Our newest paper from our common garden experiment testing whether plant-induced soil heterogeneity promotes plant species coexistence is out in the April issue of Oecologia. In this paper we show that soil heterogeneity increases per capita biomass of invaders (i.e. the disadvantaged species in a competing pair). By using a reciprocal invasion among species pairs in our experimental design, this indicates mutual invasibility by this species pair, which is a criterion for stable coexistence. Moreover, we unlock the “black box” of mechanistic drivers of plant-soil feedbacks by measuring the spatial arrangement in both biotic and abiotic soil properties within our experimentally-created soil treatments. We show that soil biota (bacteria and fungi) and phosphorous may be important drivers of the reproductive biomass response to the spatial arrangement of plant-soil feedbacks.
This paper wouldn’t have been possible without the outstanding work of Ph.D. student, Jennifer Murphy, and undergraduate student, Angela Kaczowka, along with many other students of the Burns lab who assisted with experimental set-up and data collection over the 4 years of the experiment.
Our paper on evolutionary priority effects in New Zealand forests has been selected as the Editor’s Choice article in the upcoming issue of Journal of Ecology — the editors wrote this great blog post summarising our findings and the implications for our understanding of ecological communities. And one of my co-authors and one of our lab’s PhD students kindly supplied me with useful (and attractive!) photos to include in the blog post.
Our paper showing an evolutionary legacy of community assembly in New Zealand forests, an evolutionarily older and more structurally complex ecosystem than investigated to date, is now in early view online at the Journal of Ecology. We have shown that evolutionary priority effects — where early-arriving ancestral taxa diversify and preempt niche space, precluding later arrivals from dominating new habitats — shape extant communities of both pteridophytes and angiosperms. These physiologically-contrasting taxonomic groups exhibit different responses to precipitation gradients, however. Evolutionary priority effects in pteridophyte communities become stronger with increasing precipitation, as predicted by the hypothesis that competition has a greater role in structuring communities in benign or resource-rich environments (i.e. the Stress Gradient Hypothesis). Angiosperms show a different pattern, with stronger priority effects in the drier eastern portion of the mountain range we sampled, suggesting that environmental drivers other than precipitation may be more important in structuring angiosperm communities. Our work thus advances current understanding by showing a remarkable consistency of clade age effects on community dominance across different ecological conditions — more structurally complex ecosystems and longer evolutionary timescales, as well as across physiologically-contrasting taxonomic groups.