Joss Sibbering Initial Dissertation Presentation

Jocelin Sibbering

1: Context

  • Wet woodlands research
  • Conservation and restoration


  • Multiple successional pathways
  • Ecological tipping points
  • Novel Ecosystems
  • Rewilding

Papers
Forgotten Forests

“…there have been no rigorous wet woodland biodiversity studies across the range of taxonomic groups and wet woodland types in the UK. Thus, there are key knowledge gaps on the unique assemblages of wet woodlands, the environmental tolerances of wet woodland species, the role of microhabitats and microclimate on biodiversity now and under climate change, the importance of connectivity, and how the (eco)hydrological conditions at macro- and micro-scale influence biodiversity, above-ground productivity and carbon sequestration.”

(Milner et al, 2024)

Gaps in Research
  1. Assemblages of wet woodlands
  1. Environmental tolerances of wet woodlands
  1. Roles of microhabitats and microclimate on biodiversity now and under climate change
  1. The importance of connectivity
  1. How ecohydrological conditions at macro and micro scale influence biodiversity, above-ground productivity and carbon sequestration.
Gaps in Research


Previous structural diversity measures have been found to miss important features of the wet woodland ecosystem such as canopy openings from tree fall.


Image from: https://www.flickr.com/photos

/gatesofmemphis/3712343158/

The UK’s current management guidelines for wet woodlands are 30 years old


Forestry Commission Practice Guide: The Management of Semi-natural Woodlands 8. Wet Woodlands (Printed 1994, reprinted 2003).


This was before the current focus and targets on carbon sequestration were developed (Milner et al, 2024)

Importance of this research

Structural diversity mapping can help influence:

  • “Natural” forest conservation, restoration and management.
  • Analysing resilience of ecosystems (to climate change).
  • Understanding of the role of structural diversity within other measures of diversity.
  • Habitat provision for endangered species.

2: Scientific Question(s)

“How does the species’ composition of wet woodland compare to that of associated dry forest and non-forested wetland?”


“How will species assemblages of wet woodlands be affected by climate change?”


“How does the structural diversity of wet woodland compare to that of equivalent non-forested wetland or dry forest?”

Structural diversity of wet woodland
  • Available to be researched alongside the Wet Woodlands Research group in Wheatfen nature reserve, Norfolk.
  • Existing data has been collected, though fieldwork is likely still needed.
  • Possible to do an “incomplete” structural diversity analysis for masters, before continuing with a more rigorous project in PhD?
  • WWR would be happy to support me, even helping me publish this research at the end.
Structural Diversity

Measures:

  • Volumetric capacity (occupied or unoccupied)

  • Physical arrangement

  • Identity/traits of biotic components (mainly sessile, though other biota also count)

Need to consider what technology is available and how much time is allocated for data collection. (eg. terrestrial LiDAR scanners)

Source: A theoretical framework for the ecological role of three‐dimensional structural diversity, LaRue et al 2023

Measuring Structural Diversity

Storch et al 2018 arrived at 11 measures for structural diversity, related to:

  • DBH (live and dead)

  • Diameter of downed deadwood

  • Stand height

  • Decay classes

  • Bark-diversity index

  • Flower/fructification diversity

  • Tree species richness

3: Hypothesis


Wet woodland shows a higher structural diversity than either dry forest or non-forested wetland.

  • Could be further developed into something more specific?
Hypothesis supporting literature


This paper analysed structural diversity of forested wetlands in Atlantic Canada, seeking a measure to distinguish firested wetland from upland forest. The results showed no siginificant difference.


Spatial patterns of vegetation structure and structural diversity across edges between forested wetlands and upland forest in Atlantic Canada (Harper, Gray and Querry, 2021)

4: Predictions

1:

  • The physical features of wet woodland make it difficult for tree species to remain standing beyond a certain height.

  • This leads to frequent canopy openings, increased horizontal structure and prevalence of deadwood.

  • This creates a higher diversity of niches and thus higher structural diversity beyond that expected from dry forest or unforested wetlands.

Predictions (cont.)


2:

High temporal and spatial structural diversity due to changing water levels, premature tree fall and spatial variation in inundation lead to a diverse array of niches and thus higher structural diversity beyond that expected from dry forest or unforested wetlands.

Predictions (cont.)


3:

High species turnover due to poor growing conditions gives more opportunities for unique and rare species, including pioneer species, late-stage species and flood-tolerant species.

5: Project Structure

  • Literature search – Research how to measure structural diversity
  • Record search criteria and key points
  • Research feasible structural diversity recording methods
  • Look up funding opportunities
  • Write systematic review
  • Visit site
  • Finalize research question – Find out what data is out there eg. Ted Ellis recordings/bryological survey
Project Structure (cont)


  • Contact organisations that could assist with research
  • Collect data - spend weekend in Norfolk.
  • Data wrangling
  • Write research paper
  • Poster sessions?
  • Publish paper?