Ants play an important role in every terrestrial ecosystem where they fulfill multiple functions such as providing a large proportion of the animal biomass, being the major arthropod predators and representing important distributors of plant seeds. Additionally, they have been successfully used

as biological control agents. Therefore, ants have ahigh potential to actas bioindicators.

Nowadays all around the world the flora and fauna is becoming increasingly monotonous due to the invasion of alien species. Many of these species are typical for disturbed areas and they have a high potential to colonize new areas, where they are often able to displace indigene species. This is causing a global loss of biodiversity. However, a recent study showed that certain habitats, although located in an urban area, are still able to maintain a diverse ant fauna. The main objective of this study is to quantify on which extent biotic homogenization is effecting ant communities.

The study will clarify how many species are native, and how many are introduced. For introduced ants the proportion of invasive species (meaning they have a negative impact to native species) will be estimated. This study will also quantify changes of ant species richness across a gradient of urban habitats located within and at the border of the city of Bogor. The gradient will range from buildings, gardens and traditional markets towards annual agricultures, tree plantations and highly disturbed secondary forest patches or scrub fallows along rivers and forest edges. Ants are collected by several sampling methods (manual collecting; baiting with honey), which are capable of recording partly different fractions of the present ant species assemblage. We collected 94 species for 19 different sites in this study. Most of them are identified as tramp species. 6 species are dominating in Bogor: Odontoponera denticulata, Paratrechina longicornis, Tapinoma indicum, Anoplolepis gracilipes, Dolichoderus thoracicus, Pheidole plagiaria, and Tetramorium simillimum. We found two species which are well known as invasive species (based on McGlynn 1999, Biogeography 26:535-548). These species are O. denticulata and P. longicornis, which both were found and dominated in almost every habitat on each location. Although the species were identified their provenience is still doubtful. In this study we hypothesized about native species, which are only found in one location. Our preliminary conclusion showed that habitats with high human disturbance have low ant diversity with higher tramp species ratios and constant presence of invasive species. This leads to the conclusion, that tramp species, especially invasive ones, have dominated the urban habitat, with a huge impact on native ant communities. In other locations like forest edges, small forest patches, and parks the diversity is still relatively high. This can be explained by the fact that some native elements still survived there.

Effects of Forest Disturbance of Ant Community Structure at Salak Mount, West Java (Indonesia).  (Funded by Chevron Corporate)

The effects of forest destruction on the ant community structure in Mount Salak were studied between March and September 2004. The ecological research was conducted at four different locations covering three habitats (undisturbed secondary forest, disturbed secondary forest, production forest) by using pitfall traps. So far, we found 4477 individuals belonging to 34 genera at Mount Salak. The genus Pheidole is commonly found in all forest types where it is distributed equally. Covering more than 50% of all collected specimens the individual number of the genus Pheidologeton dominates the ant communities. However concerning this genus the number of individuals was extremely low in minor disturbed forests compared to other forest types. The findings from different areas at Mount Salak showed that the species composition of ant communities was significantly related to the habitat type. Our analyses indicated that forest disturbance significantly affects the structure of ant communities. The community-structure of ants was completely different at different forest types. Several species could be only found in one forest type. Our data indicates that there is a site-specific species composition of ant communities and forest transformation may contribute significantly to the presence of single species.

Effects of Island Characteristics to Ant Community Structure In Kepulauan Seribu, West Java, Indonesia

This research started at the beginning of 2006. Data collection and analyses were completed in August 2006. Eighteen islands differing in area, isolation from the mainland, land-use history, and the presence of docks were selected to study these effects on species richness and the structure of ant communities.  Several key results from the research were (1) island characteristics tend to influence species composition (2) several ant species were strongly affected by island isolation and land-use. (3) human-induced habitat modifications on islands were identified as the main factor for the occurrence and distribution of tramp species within Kepulauan Seribu. Now we are still working on scientific manuscript for publication and guidebook of ant from Seribu Islands.

Invasive Alien Ants in Small Island of Kepulauan Seribu Sanctuary- Indonesia: Its Possible Impact toward Local Ant Communities (Funded By BEHF-Wildlife Trust)

Alien invasive ant species are major threats to indigene and endemic ant species for small islands such as in Seribu Islands. The main objective of this project was to quantify to which extent invasive ant populations is affecting native ant communities that may be endangered and endemic. The study clarified how much species are native and endemic, and how much are introduced and invasive. Ecological observation have been conducted in three different islands representing three conditions: highly populated island, unique bird island, and unexplored island. Ants have been surveyed by pitfall traps and leaf litter sampling (winkler method) in 5 m x 5 m plot. We recorded that some ant species were not found anymore in Bokor, Rambut and Untung Jawa i.e. Philidris sp.01, Philidris sp.02, Tapinoma sp.07, Crematogaster sp.70, Amblyopone sp.01, Hypoponera sp.04, Pachycondyla sp.42, and Tetraponera sp.01.  Based on several references, there were no endemic or endanger species in Kepulauan Seribu.  All species in Kepulauan Seribu can be found in Java Island (Main Island).  In this research, we also found that invasive ant species can shapping the ant species composition on the islands.