Hannah White: Looking at historical climate helps map current ecosystem stability

In this post Dr Hanna White, lecturer at Anglia Ruskin University in Cambridge, presents her latest work “Ecosystem stability at the landscape scale is primarily associated with climatic history”. She discusses how biodiversity could not be enough to maintain a stable plant productivity in a changing climate, the importance of ecosystem monitoring and why ecologists are a great community for doing science.

About the Paper

Hannah White
Hannah White

Plant productivity is a vital ecosystem function, keeping us and other organisms alive. It is crucial, therefore that plant productivity is maintained and stable over time in the face of global environmental change. To do this, we need to understand the factors that shape spatial variation in temporal ecosystem stability.

Previously, stability of plant productivity has been studied at the field scale using experimental plots. We, however, took a landscape scale approach, scaling up previously studied relationships (e.g. biodiversity-stability relationship) and investigating new ones too, to determine the drivers of stability at a scale relevant to land managers under real world conditions. We used a time series of remotely sensed data of the Enhanced Vegetation Index to measure multiple dimensions of stability (variability, magnitude of anomalous events, recovery time and recovery rate) and investigate the factors that shape the variation of stability across the island of Ireland. Our idea was to investigate not only the ecological but also the environmental context of an area, and how this influences stability. We studied the relationship of temporal stability with biodiversity (the species richness of vascular plants), landscape heterogeneity (the Shannon diversity of land covers in the surrounding area), and climatic history (variation and extreme events in temperature and precipitation in the 50 years prior to the study period).

The key message from the paper is that different components of landscape scale stability in agricultural grasslands are primarily driven by the climatic history of an area. Contrary to our original hypotheses, however, the relationship was not always positive. A history of a variable climate, for example, did not always promote stability, sometimes leading to lower stability of plant productivity. Although there is some suggestion of a positive effect of biodiversity on stability at the landscape scale, this effect is generally outweighed by climatic factors. The incorporation of climatic history is relatively unique in this research field but, from our results, is clearly a very important thing to consider!!

This paper is part of a cross-border project between researchers in the Republic of Ireland and Northern Ireland investigating the stability of grasslands at different spatial scales (https://www.ucd.ie/ecomodel/resilience.html). Ireland has suffered multiple fodder crises where the reduced plant production for fodder has had huge economic impacts. Understanding the mechanisms underlying the dynamics of plant productivity in agricultural grasslands in time can help as promote stability and therefore contribute to food security.

About the Research

A typical Irish landscape – agricultural pasture. Photo credit: Jon Yearsley
A typical Irish landscape – agricultural pasture. Photo credit: Jon Yearsley

In the face of ongoing global environmental change, being able to monitor ecosystem functioning in time is vital for the continued processing of the planet. It has implications for multiple ecosystem services including global food security, which is crucial with an increasing global population.

Combining remote sensing data with biological recordings data allows the investigation of ecological theories across large spatial scales. Although this has its challenges, for example accounting for recorder bias within the biodiversity data, the methods we use can be applied to multiple systems, for example forestry research, and a variety of environmental stressors and disturbances, including vegetation recovery following fires or deforestation.

Our research opens up a new set of questions and multiple lines of research regarding the mechanisms through which climatic history impacts ecosystem stability. Disentangling these mechanisms will be key in future proofing our landscapes in the face of ongoing climate change. Additionally, although climatic history outweighed biodiversity effects in our models, we were only able to scale up species richness estimates to the landscape scale. Investigating additional biodiversity components such as functional diversity may prove fruitful in understanding the influence of the ecological context of the landscape on ecosystem stability.

About the Author

I am a Lecturer in GIS and Spatial Ecology at Anglia Ruskin University, Cambridge, UK. Like most ecologists, I have always been interested in the natural world, whether through watching nature documentaries or weekends spent rock pooling at the beach during my childhood (…and adulthood). I did a very broad undergraduate degree with only a little bit of ecology, but decided to do a MSc in Ecology, Evolution and Conservation, as I enjoyed these aspects of my course. It was during this time that I discovered what macroecology was, and realised that it encompassed all the things I was interested in: Why are things where they are? How has this changed?  How will this continue to change?. Since then, I’ve continued to investigate biodiversity patterns, traits and functioning with a macroecological lens, as trying to find the generalisable patterns that exist in the natural world really fascinates me.

Recently, I have been investigating the commonness and rarity of species and how this contributes to multiple aspects of biodiversity, which can in turn impact ecosystem functioning. I am also bringing together my research interests in community ecology, species traits and ecosystem stability to investigate the relationship between these across different taxonomic groups. Despite my research being primarily desk-based, I am definitely an outdoors person. I love running, hiking and sea swimming, although I have to admit, an indoor heated pool is often more appealing. After reading scientific literature during the working day, in the evenings I like to completely escape with a fiction book. This, along with cooking, really helps me switch off from work. 

One of my favourite things about being an ecologist is that the ecological community is fantastic, probably because everyone is so passionate about the subject and we’re really trying to produce valuable research that will make a difference. It is because of the collaborative nature of the ecology community that we are able to produce progressive research such as our paper in Functional Ecology. Surrounding yourself with good people makes such a difference in research and would be an important piece of advice I would pass onto anyone in the field.

Read the article in full here

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