IAP2-23-060

Uncovering the effects of climate change on forest ecosystems through the lens of animal behaviour

Ecosystem services have an estimated economic value of more than £25 trillion per year. Insects are particularly important ecosystem-service providers in terrestrial ecosystems, but they are also especially vulnerable to climate change, which might affect their capacity to provide ecosystem services, such as nutrient cycling and decomposition [1]. Understanding how the effects of climate change on ecosystem processes are mediated by these organisms presents a key challenge for biologists.

To address this timely issue, this PhD project will integrate animal behaviour and ecosystem ecology, combining laboratory work and field experiments. It will focus on Nicrophorus burying beetles, which are obligate scavengers and are known as nature’s undertakers. They are valuable ecosystem-service providers in woodlands and forests, because they breed on animal carrion, which is the most nutrient-rich form of organic matter [2]. As a part of their elaborate parental care, burying beetles deposit antimicrobial substances on the carcass to prevent bacterial and fungal growth, which influences the rate of decomposition [3]. Previous work has shown that the presence of burying beetles in terrestrial ecosystems plays an important role in promoting nutrient cycling and improving soil fertility [2]. In the absence of scavengers such as burying beetles, decomposition is mainly driven by fungi and bacteria, causing the release of large amounts of gases and the leaching of exudates into the soil [3]. This can have long-lasting effects on soil biochemistry as well as the functionality of the microbial community [3]. Prior work has also shown that at higher temperatures burying beetle parents provide less care (including the deposition of antimicrobial secretions on the carcass), potentially due to increased energetic costs [4]. This reduction in parental care under warmer conditions could thus have consequences for the rate of carcass decomposition and nutrient cycling in the soil.

The general aim of this PhD project is to link temperature-induced behavioural changes at the individual level to ecosystem-level processes in a global change context. We will use a combination of lab and field experiments to examine how climate change may affect nutrient cycling and other ecosystem processes through its effects on the parental behaviour of burying beetles. For example, we will examine the effects of temperature on the carcass maintenance behaviour (i.e. antimicrobial secretions) of burying beetles and, in turn, whether this leads to changes in the soil biota or physical and chemical changes in the soil.

More specifically, some potential topics the student could focus on are as follows:
1) Nicrophorus habitat specificity, abundance and distribution in forest habitats in the UK
This would constitute the first step in determining where burying beetles are most common and thus which types of habitats they might have the greatest impact on.
2) Effect of Nicrophorus activity on soil biota
Burying beetle breeding constitutes a pulse of nutrients, and soil biota is distributed in clusters based on resource availability. We will also characterise potential soil physical and chemical changes.
3) Modular effects of mesofauna on microbes
We will examine microbial activity to quantify nutrient cycling under different environmental conditions.
4) Avenues for mitigating such effects of climate change on ecosystem processes
We will experimentally test whether understory vegetation and litter on the forest floor can mitigate the effects of elevated ambient temperatures by creating a cooler microclimate beneath the soil surface.

This work will be done in collaboration with Forest Research, the research agency of the Forestry Commission and the UK’s principal organisation for forestry and tree-related research. As a CASE PhD studentship, this will include an internship at Forest Research in Edinburgh, Scotland.

Year 1

Research training
Design and plan experiment
Start experimental work (lab)
Data analysis for completed lab work

Year 2

Complete experimental work (lab)
Start field-based experiments
Continue data analysis
Start writing dissertation

Year 3

Complete field-based experiments
Complete data analysis
Continue writing dissertation

Year 3.5

Complete dissertation writing

The PhD student will employ a wide range of techniques both in the laboratory and the field. Field sites are likely to be mainly in Scotland, but there is some flexibility depending on the student’s particular interests and the specific project aims. The student will gain skills in soil biochemistry and microbiology, behavioural observations, animal husbandry, and statistical modelling. There will also be a strong focus on transferrable skills, such as project management, written communication, and oral communication.