Statistical Methods for the Joint Analysis of Spatial, Sparse or Missing Ecological Data
To mitigate biodiversity loss, we need to understand the environmental and demographic causes of changes in the distributions and abundances of species. Bird populations are in a continual state of flux; these fluctuations can be explained by changes in vital rates, such as survival and productivity...
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| Format: | Thesis |
| Language: | English |
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2020
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| Online Access: | https://kar.kent.ac.uk/79692/ https://kar.kent.ac.uk/79692/1/108JimenezMunoz_Marina_thesis_afterviva.pdf |
| Summary: | To mitigate biodiversity loss, we need to understand the environmental and demographic causes of changes in the distributions and abundances of species. Bird populations are in a continual state of flux; these fluctuations can be explained by changes in vital rates, such as survival and productivity (breeding success). This thesis is the result of three different ecological projects for which we have developed statistical methods that combine different types of data together. In particular, in this thesis we describe, implement, and develop statistical models that can be applied to different types of ecological data such as census, ring-recovery, and capture-recapture data. In the first project we use data from the British Trust for Ornithology (BTO), which has developed an extensive historical data set of the total number of birds ringed in Britain and Ireland, dating back to 1909. However, until 2000 the data were submitted by ringers in paper form. The way in which such archival data were collected and stored means that the total number of birds ringed in different age categories is difficult to obtain. Bird survival changes with age, with younger birds being more vulnerable. Missing information on the age at ringing compromises our ability to understand historic variation in survival rates. We examine suitable methods and propose a new model for enhancing the use of such data. Using blackbird (Turdus merula) and sandwich tern (Thalasseus sandvicensis) data we show the rigour of our model in estimating unknown age proportions for different species, allowing the BTO and other European institutions to fully utilise their historical data. Bi-parental care is crucial in the reproduction success of the little auk (Alle alle) which we study in the second project. For this species, typically, the female deserts the brood before the male does. Hypotheses which considered that females left the nest earlier in order to increase their remating success or to secure their good body conditions have been rejected. As a ... |
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