Impact of human colonisation history on New Zealand avian diversity : a thesis presented in partial fulfilment of the requirements for the degree of Doctor of Philosophy in Ecology at Massey University, Auckland, New Zealand
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Date
2016
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Massey University
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Abstract
Human activity has transformed earth's ecology and exerts new selection forces on entire species
communities. This thesis examines the influence of evolutionary and human history on the
composition of local biodiversity in New Zealand terrestrial habitats. The Auckland region of New
Zealand provides an excellent model system because these areas have only recently been colonised
by humans, and there is a gradient of habitats ranging from urban to protected native bush. The
history of humans in New Zealand is used to inform the response of naïve biodiversity to
anthropogenic transformation. First, a general concept of the effect of human societies on
biodiversity responses to anthropogenic impacts is explained in chapter one. I focus on three major
historical phases - hunter-gather, Agrarian and Industrial- to outline the contrasting influences of
each society on native species extinction and extirpation legacies. I then examine the impact of two
waves of colonization by humans in New Zealand on avifauna, to establish an understanding of the
influence of different human societies on species communities. My results show that New Zealand’s
extinction rates are the highest recorded, and are associated with the post-colonisation period by
European society and a more advanced human niche construction. This caused more advanced
cultural, ecological transformations at various spatial scales. In addition, for exotic bird species in
New Zealand, I examined whether the extent of previous coexistence with humans was a potential
determinant of establishment success. My findings suggest that previously co-existing with humans
is a potential key factor driving the establishment success of exotic species, particularly in habitats
transformed by humans. To verify the idea that species functional diversity responds in different
ways to human civilisation, I characterise differences in species biological traits among a gradient
of habitats with variable degrees of anthropogenic disturbance. I show that no clear assemblages of
traits are currently found along extant New Zealand native avifauna. I argue that this can be
explained by the different experiences that NZ native avifauna has had with humans in comparison to exotic species. To investigate the possibility of a time-lag response of birds to human habitat
transformations, the response of an avifauna assemblage in a remnant forest in the urban habitat is
investigated over a period of 26 years of human habitat changes. My results suggest that the
community assemblage changed over that time, driven by the arrival of new exotic species. This
resulted in a change of community composition to one dominated by exotic species. Finally, nestsite
selection of exotic and native avifauna is examined across an anthropogenic gradient to
understand the role of evolutionary history in shaping their behavioural response to habitat change. I
found further support for the effect of species past-experience with humans. Indeed only native
species more naive to anthropogenic habitats and its disturbance tend to alter their nest site strategy
in relation to the degree of terrestrial predation. By using the history of a recently colonised location
like New Zealand, this research has been able to show the potential importance of human society
characteristics during colonisation and how previous levels of human coexistence of biodiversity
has implications for current and future ecological consequences in an Anthropogenic world. This
thesis highlights the importance of considering species’ past-experiences with humans to inform
ecological and evolutionary research and conservation strategies.
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Keywords
New Zealand, Colonization, Environmental aspects, Land settlement, Human ecology, Birds, Effect of habitat modification on, Geographical distribution, Variation, anthropogenic disturbance, anthrosequence, environmental change, time-lag, past-evolutionary history