Welcome to the spring docent lectures at the S Faculty

Assoc. Prof. Michael Bertram 
Department of Wildlife, Fish, and Environmental Studies  
Faculty of Forest Sciences 
Swedish University of Agricultural Sciences 

Animal behaviour is highly sensitive to disruption by chemical pollution, with potentially far-reaching consequences for ecological and evolutionary processes in contaminated wildlife populations. However, many of the approaches conventionally used to study pollutant effects on animal behaviour do not fully capture the complexity of the natural environments in which contamination occurs. Much of the existing research in this area has focused on single species, single chemicals, and 
individual behaviours measured in confined arenas. Although these studies have been essential, they provide only a partial picture of how pollution affects animal behaviour in the real world.  

In this lecture, I will discuss how behavioural ecotoxicology is developing from simplified laboratory tests towards approaches that can reveal how contaminants affect animals under more realistic conditions. I will highlight three main areas in which the field is advancing: increasing environmental realism, better accounting for ecological complexity, and applying new methods that allow behaviour to be studied with greater accuracy and detail. This includes topics that have so far received limited research attention, such as social behaviour and collective dynamics in 
contaminated animals, interactions among multiple stressors, and differences among individuals in their responses to contaminants.

I will explore these themes through selected examples from my research programme, including field based work on Atlantic salmon (Salmo salar) in the River Dalälven, where my team investigated how exposure to pharmaceutical pollutants influenced river-to-sea migration behaviour. This work illustrates how contaminants can alter behaviour under natural conditions, and underscores the value of combining field studies with mechanistic and experimental approaches to better 
understand when behavioural disruption is likely to have broader ecological consequences.

Overall, the lecture will emphasise behaviour as a key pathway through which contaminants can influence ecological systems, and will highlight the need for a stronger ecological perspective within ecotoxicology. I will also outline future directions for my research, including the integration of environmentally realistic exposures, multiple-stressor approaches, and high-resolution field methods 
to improve our ability to predict when contaminant-induced behavioural changes are likely to scale up to affect wildlife populations. 

Ke Zhang  
Department of Forest Mycology and Plant Pathology 

Conifer trees, specifically Norway spruce and Scots pine, dominate the forest in Fennoscandia. In Sweden, these two species account for about 40% of the standing volume in the forests each, holding significant ecological, economic, and cultural value. Their resilience is critical for sustainable forestry and ecosystem services.

My current research focuses on one of the most damaging diseases in Swedish forests: Scots pine blister rust (SPBR). The fungal pathogen, Cronartium pini, infects pine through needles or young shoots, eventually causing stem deformation and the death of branches, tree tops, or the whole tree. This disease has existed in Swedish forests for more than one hundred years without significant damages; however, more severe epidemics have been reported in recent decades. Our studies in Sweden and Finland found that the epidemics are associated with various 
environmental factors such as higher temperature and precipitation in June. Climate change is predicted to promote the SPBR epidemics in northern Sweden, therefore, more knowledge on this critical pathosystem is needed for disease management. 

The causal agent C. pini is more complicated than regular rust fungi. It has two life-cycle forms: an autoecious form that completes its entire life cycle on pine, and a heteroecious form that requires two host species. The two forms are morphologically indistinguishable, but digital PCR and germination-based protocols have recently been developed for fast identification. New knowledge acquired through this development presents opportunities to address fundamental questions in forest pathology and mycology.

Breeding resistant pine is one of the most promising strategies to control SPBR. While it is known that resistance to SPBR is heritable, the genetic determinants underlying both qualitative and quantitative resistance in Scots pine remain largely unknown. To systematically identify resistant pine genotypes or clones, reliable artificial inoculation is needed to screen the pines in the forthcoming screening centre. Protocols for inoculating the two forms of Scots were developed recently and the colonization of the pathogen can be detected and monitored by microscopy and 
molecular methods. These protocols are the foundation for future studies on the genetic basis of host resistance and host-pathogen interaction.

Suitable environment, susceptible host, and virulent pathogen are the three key components in plant disease triangle. By addressing these three components in the SPBR pathosystem, my research line aims to mitigate the damage caused by SPBR and support the future forest health.