New Caledonia, an archipelago situated in the South-West Pacific Ocean has a very high biodiversity of which many flora and fauna species are endemic, and is therefore considered as one of the world hotspots for the biodiversity conservation. Sclerophyll forests, one of the five main vegetation types occurring on the island are mainly threatened by anthropogenic activities. Rusa deer (Cervus timorensis russa) were introduced into New Caledonia from Java in 1870. They have colonised all the biotopes of the main island, and represent one of the major threats to the New Caledonian sclerophyll forests. Currently, there is a lack of management tools to monitor the trends of rusa deer in New Caledonian sclerophyll forests. To test monitoring methods for use as management tools, six sclerophyll forests study sites were studied using direct census methods (i.e. spotlight count and drive count), indirect census methods (i.e. faecal standing crop method) and three indices (i.e. the faecal pellet groups index, the browsing index and the antler rubbing index). The faecal pellet groups index is based on sampling pellet groups in plots along transects. To ensure reliable data collection with a coefficient of variation of the mean number of intact faecal pellet groups per plot per transect of less than 20 percent, my study indicated that 15 plots per transect and 20 transects per sites should be sampled in New Caledonian sclerophyll forests whereas previous studies conducted in New Zealand indicated that a minimum of 25 plots per transect and of 18 transects per site should be sampled. The advantages of reducing the number of plots per transect and of transects per site is that it reduces the expenses (e.g. time, finance) and the bias due to data collection (e.g. fatigue, boredom and visual activity) which will improve the precision of the data recorded. Estimates of rusa deer density obtained from the census methods were not correlated (r = - 0.425, df = 4, P = 0.401) due to my small sample size. The reliability of these estimates is questionable because of biases. Previous publications have shown that biases are difficult to avoid when using direct census methods and that it is difficult to estimate the size of animal populations with accuracy and precision. The faecal standing crop method was subjected to bias because the estimation of the decay rate and the defecation rate were unreliable. These methods were not recommended for rusa deer management in New Caledonian sclerophyll forests. Of the three indices tested, the faecal pellet groups index and the browsing index based on unpalatable browse species were the most reliable as the confidence intervals of these two indices were small (i.e. from ±0.08 to ±0.11 for the faecal pellet groups index; from ±0.04 to ±0.27 for the browsing index of unpalatable browse species), and they also showed significant correlations with a subjective ranking of the rusa deer density based on expert knowledge (rs = 0.829, df = 4, P = 0.042 and rs = 0.829, df = 4, P = 0.042 respectively). These two indices appear to show the most promise for use as management tools, as they could reliably track local variations of rusa deer densities on the sclerophyll forests. These two indices could be used by wildlife technicians in New Caledonia to establish management plans of rusa deer populations which rely on participative management involving the stakeholders (e.g. hunters, forest managers, local communities). We believe that the faecal pellet groups index and the browsing index could be useful to monitor rusa deer populations in New Caledonian sclerophyll forests, and meet conservation and hunting objectives of the local population and authorities. Management tools such as culling and hunting operations will be implemented in New Caledonian sclerophyll forests where monitoring of indices I recommended show an increase in the deer population. Stakeholders will be involved in the implementation of the monitoring tools (i.e. indices) and of the management tools (e.g. culling and hunting operations, fencing) but also in decision making for the management of the rusa deer in New Caledonian sclerophyll forests.
| Identifer | oai:union.ndltd.org:netd.ac.za/oai:union.ndltd.org:nmmu/vital:10750 |
| Date | January 2008 |
| Creators | Roques-Rogery, Guillaume |
| Publisher | Nelson Mandela Metropolitan University, Faculty of Science |
| Source Sets | South African National ETD Portal |
| Language | English |
| Detected Language | English |
| Type | Thesis, Masters, MTech |
| Format | xii, 75 leaves : ill. ; 30 cm, pdf |
| Rights | Nelson Mandela Metropolitan University |
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