Identifying the mechanisms linking savannah degradation and bird distribution change

Degradation of savannahs threatens both biodiversity and pastoralist communities who depend on them. Some 15% of northern Tanzanian savannahs show evidence of serious degradation due to altered grazing and rainfall patterns. We have previously shown that local extinctions of birds in Tanzania are commonest in degraded landscapes suggesting birds may be a useful index of degradation, but we do not know the mechanism that drives such declines across multiple guilds. We hypothesise that they are mediated through changes in grass quality and invertebrate populations and this project is set to test these ideas.
We have recently used remote sensing to map degradation across Northern Tanzania and have started experimental trials involving grazing and fire
management to restore missing ecological processes in degraded landscapes of northern TZ. This work provides a background resource upon which the current
project has been built. To undertake the work will require uses remote sensing, field and laboratory experiments to identify the mechanisms linking degradation
to bird population declines and to assess whether bird populations indicate savannah health.
Specifically, we will test the hypotheses that:
Savannah bird populations and communities are associated with vegetation structure and quality, and invertebrate abundance and community.
Grass quality and quantity is altered by grazing and fire management.
Insect herbivore populations respond rapidly to these changes, driving changes in bird abundance and distribution.
To test these hypotheses, the student will gain skills in analysing remotely sensed data to identify degrading landscapes, will gain field experience surveying birds, invertebrates and vegetation across northern Tanzania (including within our experimental management plots) and will under lab work to quantify vegetation quality. Analysing these data will involve detailed statistical analyses, including machine learning and spatial analysis alongside modern statistical methods.
The student will be based in the Biology Department at the University of York, in research groups with an active programme of post-graduate research in African
savannah ecology and in plant-invertebrate interactions, with regular fieldwork at established sites in northern Tanzania.