Thread by @RewildingS

We’re offering some #rewildingscience for the weekend today in the shape of @Nature_Based 2013 paper which seeks to answer to the question are wild boar effective ecosystem engineers? #rewilding 1/

An #ecosystemengineer is defined by the paper as species which create, modify, maintain, or destroy habitats for other species and that have a strong effect on ecosystem functioning. These are useful species in habitat management, but their impacts need to be understood. 2/

The paper is focused on the Scottish highlands where, as it points out, there has been extensive habitat destruction and species expirations over the past millennium. With data collected within a 125ha fenced area of the Alladale Wilderness Reserve. 3/

It uses the wild boar as its focal species due to them being an extirpated engineer of Scotland that could be used to promote Caledonian Pine Forest regeneration due to the regenerative nature of their foraging behaviour 4/

The paper studies the behavioural ecology of wild boar, to better understand their potential uses and ecological implications of a reintroduction. With two primary hypotheses... 5/

(1)Wild boar will preferentially use grass-dominated vegetation and grazing behavior in the spring and summer months. (2) Wild boar will preferentially use bracken-dominated vegetation and rooting behavior in the autumn and winter months. 6/

Four 2-yo females and one 3-yo female, reared in captivity were fitted with GPS collars, with hourly movement data recorded throughout each season. Maximum and minimum collar angle and ambient temperature recordings were also made before each hourly location recording 7/

Monitoring sessions were carried out to assess behaviour, these were also carried out prior to the main study to acclimatize boar to the observer and practice the monitoring protocol. With the following protocol established 8/

Results showed that wild boar exploited seasonally variable resources and had variable impacts on vegetation communities both spatial and temporally. With grazing behaviour preferred in the spring and summer and rooting in autumn and winter 9/

The study suggests this shows that wild boar can be important engineers, by creating germination niches for other plant species. This could be beneficial for habitat management. It also suggests importantly that wild boar contribute as both grazers and disturbers 10/

Wild boar displayed deep rooting behavior within bracken dominated vegetation while shallow rooting within grass-dominated communities. As the paper points out, bracken is often a problem for conservation managers, so wild boar could provide a useful solution to this problem 11/

The results also showed a preference for canopy cover around extant woodland patches. It is suggested that this could create space for shade tolerant species to establish, while when rooting occurs in canopy gaps light demanding and more competitive species may occur 12/

The paper points out that optimal habitat (e.g. oak woodland), other potential food resources (e.g. crops), and predators were absent in this study area, which may impact the results. Further research to include these conditions is suggested 13/

Results also found the wild boar in the study to be diurnally active, rather than nocturnal, which they suggest is likely to be related to factors including ‘daily supplementary feeding, human activity, temperature, and the absence of predators’. 14/

Interestingly, the study found collar temperatures to be higher at night than during the day, demonstrating benefits of communal resting sites. With mean collar temperature at night just 2.8◦C different in winter and summer compared with an air temperature difference of 9◦C 15/

The study empahsises that supplementary feeding will likely be required if boar are reintroduced into fenced areas with missing woodland species. And indeed they mention that using supplementary feeding will have altered forgaing behaviour 16/

However, the absence of supplementary feeding is likely to increase their foraging activity, and authors suggest that the trends seen in different communities are likely to be maintained. 17/

The paper concludes by acknowledging the limitations of sample size and suggests research in more complex environments is needed. but suggests the results provide evidence of how wild boar behavior would impact the current Scottish Highland landscape 18/

It also shows the importance of investigating how potential ecosystems engineers interact with a new environment before considering their reintroduction or re-establishment. Implications for practice are also offered 19/

I found this paper an enjoyable read, a very neat study that clearly displays the ecological impact that could be utilised by reintroducing wild boar albeit with a limit sample size. Food for thought in the current ecological climate. 20/

I was particularly amazed by the impact of communal resting on winter tempratures and the potential impact this can have on activity budgets. 20/20

#rewilding #rewildingscience #paperreview
The full paper can be accessed here: onlinelibrary.wiley.com/doi/epdf/10.11…