Hale, J. and Butcher, R.
Department of Sustainability, Environment, Water, Population and Communities - 2010
About the document
An Ecological Character Description describes the ecological character of a wetland at the time of its listing as a Wetland of International Importance. The Ecological Character Description is a fundamental management tool for site managers, forming the basis of management planning and action as well as including guidance on site monitoring requirements to detect changes in the ecological character of the site.
Hosnies Spring Ramsar site is located on Christmas Island in the Indian Ocean. The site is located within the Christmas Island National Park in the east of Christmas Island. At the time of listing (1990) Hosnies Spring comprised less than one hectare of freshwater spring. In 2010 the boundary of Hosnies Spring was expanded from 0.33 hectares to 202 hectares.
Hosnies Spring's most notable feature is the freshwater spring with a mangrove stand. The stand comprises of two species; Bruguiera gymnorhiza and B. sexangula, both of which usually occur in intertidal zones. However, at Hosnies Spring the trees are located at the spring some 120 metres inland and 37 metres above sea level. It is thought that the stand is a relict of times when the site was inundated by the sea more than 120 000 years old ago.
The ecological character of a wetland is the sum of all the components, processes and services of that wetland. Ecosystem components are physical, chemical and biological parts of a wetland, from large-scale to very small-scale (e.g. habitat, species and genes). Ecosystem processes are the dynamic forces within an ecosystem. They include all those processes that occur between organisms and within and between populations and communities, including interactions with the non-living environment, that result in existing ecosystems and bring about changes in ecosystems over time. Ecosystem services are the benefits that people receive from ecosystems.
This document describes the critical components, processes and services for Hosnies Spring Ramsar site. Hosnies Spring has three critical components and processes: hydrological regime; land crabs; and mangroves. It also has four critical services: food webs; biodiversity; distinct wetland species; and supports near natural wetland types. The description also identifies limits of acceptable change which describe the range of variation which key aspects of the ecology of the site can vary without representing a change in the ecological character. Limits of acceptable change for Hosnies Spring have been proposed for all critical components, processes and benefits and services based on existing data.
This document also describes the current Ramsar listing criteria met by the site, the key threats and knowledge gaps for Hosnies Spring. Recommended monitoring needs and communication messages are also provided.
Further information on what Ecological Character Descriptions are and how critical components, processes and services are identified is available in the National Framework and Guidance for Describing the Ecological Character of Australian Ramsar Wetlands – Module 2 of the National Guidelines for Ramsar Wetlands – Implementing the Ramsar Convention in Australia.