Brad Farmilo submitted his PhD thesis just before Christmas titled "The internal dynamics of forest fragments". Brad's been with me these last four years, and undertaken a really neat study about the ecological mechanisms that change (e.g. herbivory, recruitment dynamics) when you grow pine forests around remnant eucalypt forest. He did this at the world's second longest experimental fragmentation study site: the Wog Wog Habitat Fragmentation Experiment, near Bombala in southern NSW.
Importantly, we think we've seen an interaction between climate drying and fragmentation as it affects plant species density. Brad's work lays the foundation for understanding how pine forest harvesting (which is due to occur soon) then subsequently affects patterns and processes in these forests.
You can check out his Research Blog here: http://wogwogfragmentationexperiment.blogspot.com.au/
It tracks his progress over the years, and provides some neat tips about undertaking a PhD.
Here's the Executive Summary of his thesis:
Virtually
all of Earth’s ecosystems have been dramatically transformed via human actions
leading to irreversible biodiversity losses. Global extinctions are expected to
result as species richness declines towards an equilibrium determined by the
amount of remaining habitat. This thesis uses the Wog Wog Habitat Fragmentation
Experiment (the second longest running experiment of its kind) in temperate
south-eastern Australia to investigate how patterns of plant species density
vary with size of forest fragments (0.25, 0.88 and 3.06 ha), as well as
identifying factors which may influence vegetation dynamics within a plantation
landscape. Species density in small fragments was higher than continuous forest
for both total and common species at small spatial scales. This finding
contradicts much of the fragmentation literature suggesting that the mature
plantation matrix may alter important within-fragment conditions, which are yet
to be documented. Small fragments were also characterized as having higher soil
moisture and canopy cover, and lower daily maximum temperatures, which is
strongly influenced by the structure of the adjacent plantation. Rates of
recruitment of the dominant shrub appear to be more pronounced within
fragments, irrespective of size, than in areas of continuous forest (although
not significant at alpha = 0.05). This finding, in concert with microclimatic
changes in small fragments, may have caused an increase in structural
complexity within fragments, which may also positively influence plant species
density in small fragments. We also show that the affect of vertebrate
herbivores on understorey seedlings is species-specific, but that their
influence is largely uniform across the fragmented landscape and continuous
forest areas. These findings have been generated from a single point in time and
therefore, it is expected that due to the nature of the landscape (forest
removal and a subsequent cycle of plantation development and harvesting) the
long-term biodiversity in forest-plantation systems will be imperiled more so
than traditional grass-forest systems because of profound ecological changes
that are occurring not just in space, but in time. In addition, many of our results suggest that
there is a minimum size of fragment to be maintained in these landscapes below
which ecological processes are disrupted and may therefore be of reduced value
to native biodiversity.