RMDA Formative Assessment 2-Title Page

Title

Investigating the effects of habitat quality on the survival behaviours of iconic Western Santa Cruz giant tortoises (Chelonoidis porteri) in the Galapagos Islands using standardised observation techniques

Affiliations

Galapagos Natural Park Directorate, Charles Darwin Foundation, Ministry of Agriculture, Galapagos Science Centre.

Abstract

It has long been understood that changing land uses can have significant impacts on the survival behaviours of many species across the natural world.

This study investigated the impact of the differing land uses in the agricultural highland regions of the Santa Cruz island, on the survival behaviours of the critically endangered Western Santa Cruz giant tortoise on their annual migration.

The study involved standardised methodolgy to observe and record simple behavioural data, alongside the local land use type, temperature of the tortoises and the environment, season, sex, and the size and vegetation types at each focal observation point.

The results showed that land use type had a strong impact on the ratio of time tortoises spent eating, walking and resting with the most time spent eating in touristic areas. Tortoises in abandoned land rested for significantly longer than did tortoises in livestock or touristic areas. Also the probability of a tortoise eating was influenced by both vegetation height and an interaction between the vegetation cover and its density. Similarly tortoises were less likely to walk as vegetation height and density increased.

This study built on previous work which showed that agricultural areas remain important habitats for giant tortoises, and that the type and characteristics of the farmland does influence their behaviour and health. This study suggests that these large generalist herbivores select areas in which they can optimise foraging efficiency and thus provides the opportunity to influence decisions around future land uses to favour their ongoing survival for example, converting existing abandoned land for touristic use. These iconic species will be an essential part of the local tourism economy, aswell as being important ecosystem engineers. Further work is warranted to investigate the effects of changing land use from one type to another on tortoise behaviour and survival.

Keywords

Galapagos, Tortoise, Land-Use, Behaviour