The three-toed woodpecker: an important biodiversity indicator and model species for the conservation of biodiversity in boreal forests.

Date:
2018/06/15

Time:
14:00

Room:
K306 Anton

The three-toed woodpecker: an important biodiversity indicator and model species for the conservation of biodiversity in boreal forests.

(Oral)

Martijn Versluijs
martijn.versluijs@slu.se

Department of Wildlife, Fish, and Environmental Studies, Swedish University of Agricultural Sciences (SLU), SE-901 83 Umeå, Sweden, Sweden
,
Jean-Michel Roberge
- Skogsstyrelsen, Skogsenheten Box 284, 901 06 Umeå - Department of Wildlife, Fish, and Environmental Studies, Swedish University of Agricultural Sciences (SLU), SE-901 83 Umeå, Sweden, Sweden

DOI: 10.17011/conference/eccb2018/107180

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The use of biodiversity indicators have been proposed as a comprehensive method for assessing conservation values at the stand scale. In the boreal biome, the three-toed woodpecker have been proposed as an indicator for high species richness of co-occurring forest birds. However, to be able to fully understand the potential of biodiversity indicators it is necessary to understand when indicators are valid indicators, as natural dynamics within boreal forest systems can effect bird communities and thus indicator values of species. To assess the impact of natural disturbances we collected data within a large-scale field experiment where we assessed the short term (4-5 years) impact of two restoration treatments mimicking natural disturbances − prescribed burning (n=10) and gap cutting (n=10), using continuous cover stands (n=20) as references − on boreal breeding bird assemblages. We performed detailed bird inventories, through territory mapping and additionally we collected data of local stand characteristics. In this study, we confirmed that the three-toed woodpecker belong to the best indicators of high species richness and abundance within resident forest birds occurring in middle and northern boreal forests. However, the three-toed woodpecker lost its indicator value after prescribed burning; in these stands the goldcrest was the best biodiversity indicator. Based on habitat associations we found that the three-toed woodpeckers is closely associated with structural complexity within forest stands, similar to co-occurring species. Thus structural complexity at such may influence species richness. Still the three-toed woodpecker can be used for conservation planning if their habitats/resource requirements are set as quantitative targets. To accommodate managers with management recommendation regarding these quantitative targets, we quantified refined habitat thresholds and related this with their foraging substrate selection. We found resource requirement thresholds by a 0.9 probability of occurrence of 1.5 m²/ha freshly dead spruce and 0.07 m²/ha dying spruce. By focal bird observations we were able to confirm that indeed modeled resources matched with important foraging substrates for three-toed woodpecker in mature forest areas. This suggest that proposed resource thresholds can be used to plan forest management concerning three-toed woodpeckers population. However, we need to consider additional habitat structures when we planning forest management aiming to conserve biodiversity.

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INTRO:
The study confirms that the three-toed woodpecker is one of the best indicators of species richness and abundance of co-occurring forest birds in the boreal zone. Management recommendations are given with quantitative targets to maintain the foraging of this woodpecker species.
MERITS:
The study is highly relevant by demonstrating that three-toed woodpecker can be used as biodiversity indicator in forested boreal landscapes, and also by setting quantitative threshold values of dead wood to managers.
CRITIQUE:
The abstract misses providing information on the methods used, e.g. the size and number of study sites, a short description of the restoration experiment, the method how species richness and abundance of the resident birds were monitored, how habitat and/or structural complexity were defined and measured, etc. Results are somehow contradictional; stating that three-toed woodpecker is one of the best biodiversity indicators of co-occurring bird species and then explaining that "further analysis of the data showed that the three-toed woodpecker is an indicator of habitat complexity rather than species richness of co-occurring species". It is also not clear that if large-diameter deciduous trees and the heterogeneity in tree species are good predictors of resident bird species, why they are not used to formulate the management options? In my view, the study on three-toed woodpecker as biodiversity indicator, and the study on defining quantitative target values of dead wood to support the foraging of this bird species should be two separate presentations.
DISCUSSION:
Studies like this highlight the importance of enhancing and maintaining special forest structural elements (large-diameter living trees, dead wood, etc.) to preserve forest biodiversity and especially cavity birds. By setting quantitative targets regarding these elements, forest managers can be effectively involved in forest conservation issues.

- - -
INTRO:
This abstract presents a summary of available studies (both published and unpublished) of the Eurasian Three-toed Woodpecker and its viability as a keystone/umbrella species.
MERITS:
It is always nice to see synthesis of available data on a topic/species and provide insight on the full body of work rather than the individual studies.
CRITIQUE:
In the third paragraph is a bit confusing and needs clarification in several areas. The authors use the phrase "strong positive correlation" without providing statistical values to back it up and this sentence is also unclear as to what two things are actually correlated with one another - suggest using "between" rather than "with" to clarify. They also use the phrase "the quality of the forest landscape" without qualifying what this mean. They also use the phrase "the species is observed to indicate general species richness..." when they mean is correlated with? Lastly, at the end of the paragraph, the authors state "requirement for dead wood and thereby susceptibility to forest management" and it is not clear if they are implying that forest management removes or creates dead wood.

It is also not clear why the Great-spotted Woodpecker is more important than the Three-toed - suggest adding a clause to clarify.

Citations are not shown in text. Because this is a summary of previous work, this is very important.
DISCUSSION:
In general, I recommend including citations where appropriate, clarifying some vague statements and qualifying statements with data or more information when needed.

The three-toed woodpecker: an important biodiversity indicator and model species for the conservation of biodiversity in boreal forests.

Date:2018/06/15

Time:14:00

Room:K306 Anton

The three-toed woodpecker: an important biodiversity indicator and model species for the conservation of biodiversity in boreal forests.

(Oral)

SEE PEER REVIEW

SEE PEER REVIEW

Date:
2018/06/15

Time:
14:00

Room:
K306 Anton