Mechanisms and impacts and of host-parasite relationships

Mechanisms and impacts and of host-parasite relationships

Mistletoes are hemi-parasitic plants native to the UK, whose ecology and impacts on biodiversity are not well understood. Due to this glaring lack of knowledge on such a charismatic species, we are lacking optimal managing solutions for the host-parasite relationship they form with native UK tree species.

Background

Parasitism, whereby one species benefits from and has negative impacts on another, is a widespread interspecific relationship with crucial implications for ecology, evolution, and societal needs. Parasites must maintain a delicate balance: too much success (i.e. fast growth and high reproduction) may kill the host, and consequently the parasite—unless it can transfer to another host; too little exploitation of the host, and the host may manage to expel the parasite. A crucial question is “how do parasite-host systems persist in the long-term?”.

This project will explore the prevalence of parasite-host dynamics using the charismatic European mistletoe (Viscum album) and its host tree species in Oxfordshire as a case study. Once an individual mistletoe has germinated and its root-like structure penetrated the branch of its host, it is stuck until the end of its life, or that of its host. Thus, mistletoes need to regulate themselves internally somehow, or be regulated externally by the host, in order to avoid exhausting their host and ultimately committing indirect mass-suicide. However, mistletoe populations have been increasing in the past decades in the UK, suggesting that there is no regulation. How then, is the host-parasite balance kept? Berry dispersal via birds and host tree specificity may be likely regulating mechanisms.

Project Description

In this project, the student will evaluate mistletoe-host dynamics using unmanned aerial, dendroecological, and physiological techniques. S/he will explore how mistletoe prevalence and population growth rates affect their host both physiologically and demographically. This knowledge will help evolutionary biologists better understand how parasitic relationships are maintained, and botanists and land managers to develop plans to control mistletoe abundance on ancient oaks and fruit trees, which have great cultural and economic value.

Aims of the Project

To examine the various ecological, evolutionary and human-social aspects that affect the delicate host-parasite balance between mistletoes and its host trees.

Methods to be used

The student will use a combination of data collection techniques such as tree climbing, cherry-pickers and unmanned aerial vehicles (drones), as well as ground-censuses to evaluate the spatial patterns of dispersal of mistletoes (e.g. birds), germination and other demographic processes.

Specialised skills required

The student will need to be proficient in R, and preferably in machine-learning. The student will also need to be capable of carrying out fieldwork and be keen on becoming a drone pilot, if not already have the license by the CAA.

If interested in this project, please contact Roberto Salguero-Gomez. rob.salguero@zoo.ox.ac.uk

Associated Pages