Golden-headed lion tamarins

GHLTs are small arboreal primates threatened by extreme habitat fragmentation and loss of the Atlantic Forest in southern Bahia, Brazil (Pinto and Rylands 1997; IUCN 2012). They are frugi-faunivores that live in small groups (5–7 individuals on average) and maintain home ranges that can be quite large (20-200 ha; Raboy and Dietz 2004; Oliveira et al 2011). In addition to mature and secondary forest, the species uses shade-cocoa plantations known locally as cabruca (Raboy et al 2004, Oliveira 2010). The species' geographic range is characterized by two distinct vegetation types: coastal humid forest in the east, where cocoa production is the predominant agricultural activity, and semi-deciduous mesophytic forest in the west, where cattle ranching is widely practiced (Pinto and Rylands 1997). Because shade-cocoa production in this region utilizes a canopy of native trees, large swaths of forested habitat are still available for GHLTs throughout the east compared to the small, fragmented forest cover interspersed by open cattle ranches in the west. However, forest throughout the species' range was lost at a rate of 13% over the last 20 years, and this deforestation rate is projected to increase as shade cocoa plantations are converted to cattle pastures following declines in cocoa prices and fungal epidemics that devastated the cocoa industry beginning in the early 1990′s (Schroth & Harvey, 2007). Additionally, planned changes to Brazil's Forest Act will eliminate enforced protection of certain areas of existing forest (Calmon et al., 2011). Because the majority of native vegetation within the GHLT range is found on private land where extreme pressure for agricultural expansion is highest (Sparovek et al., 2010; Ferreira et al., 2012), a better understanding of the needs of GHLTs and the protection of their habitat is becoming increasingly critical for the survival of this species.

Overview of existing knowledge relevant to the in situ conservation of the species

The two-day symposium was structured to allow for a day of research presentations and a day of discussion. Through 16 presentations, participants presented the major results of their recently concluded or ongoing research programs. Topics included ecology and behavior of GHLTs in various habitat types, genetic structure and health of GHLT populations, the impacts of forest fragmentation/connectivity and climate change on the species, and updates on the activities of NGOs and the status of protected areas within the species' distribution range. Following presentations, participants summarized existing knowledge on in situ GHLT biology, ecology and conservation based on past research programs/publications and on the information presented at the symposium (Tables 1 & 2). Additional information (e.g. population surveys, extensive GIS work, population and landscape modelling, genetic sampling, and health assessments) not listed in Table 2 is available at the level of the entire distribution range.

Defining priorities for future research and conservation

Following the summation of existing knowledge, participants worked in break-out groups to identify what they deemed the top five most significant research gaps in GHLT research and knowledge. Working group results were presented and discussed in a plenary session. The topics identified as highest priority research areas included:

1. Ecology, biology, health status, and genetic differentiation of western populations: Demographic and landscape modeling have demonstrated that without protective measures, all western populations are in immediate danger of extinction in the short term (Zeigler, unpubl. data). Despite this urgency, basic scientific information (i.e. ecology, basic biology, genetic differentiation, and health status) needed to develop sound conservation measures is still unavailable for these populations. Such information will improve our understanding of the species' management needs throughout its range.

2. GHLTs and cabruca agroforest: Cabruca plantations can range from heavily managed monocultures to highly natural mosaics of cacao trees and endemic tree species, and not all forms are suitable as GHLT habitat. Research focusing on the presence/absence of GHLTs and their comparative demography and ecology along the full spectrum of cabruca agroforest is essential to understanding the species' habitat and management needs and balancing regional socioeconomics with conservation.

3. GHLT dispersal and survival in fragmented landscapes: Very little is known about how GHLTs move and survive in fragmented forest; how often individuals leave forest boundaries and move through non-forest matrix, how far individuals travel through non-forest matrix, what landscape elements individuals are willing to travel through and which elements act as barriers to dispersal, the probability that dispersing individuals will survive the journey, and whether other characteristics (such as patch occupancy by GHLTs) influence dispersal and settlement. This information is critical for landscape-level conservation planning.

Table 1.

Definitions used to categorize the scope of available knowledge, sample size and duration of available studies on which the assessment in Table 2 is based.

4. A new census of the current GHLT distribution: Given continuing threats across the species' distributional range, the size and locations of populations are likely to still change/ decline. Knowing how many individuals/populations exist and where they are located is of vital importance to managing and protecting the species in addition to improving our understanding of population trends and gauging the effectiveness of conservation efforts.

5. GHLT use and behavior in unknown habitat types: Research has thus far focused on GHLTs in primary forest, degraded forest, and cabruca agroforest. Little is known regarding if and how GHLTs use other habitat types such as restinga, high altitude forest, or other agroforestry systems.

6. Threat impact analysis: Threats to GHLT survival have been identified and include broad processes like forest loss and fragmentation and climate change. Information on the specific nature of these threats and their impacts on GHLT survival, however, is limited. A better understanding of these threats is necessary for protecting GHLT populations from negative impacts.

7. Environmental services provided by GHLTs: GHLTs are hypothesized to have an important role in ecosystem functioning. Research is needed to better understand the importance of the species in maintaining the structure and viability of the Atlantic Forest through, for example, seed dispersal. Since a major part of Brazil's economy relies on Atlantic Forest resources, demonstrating that GHLTs themselves play a critical role in the functionality of the forest may be an alternative approach to securing conservation of the species and its habitat.

8. Environmental education: Research into the perceptions of local people towards GHLTs and conservation in general is important for improving our understanding of their attitudes and offers important information for developing sound, efficient and viable education and outreach programs that involve all relevant stakeholders.

Table 2.

Overview of key research topics relevant for the in-situ conservation of golden-headed lion tamarins and the current level of available knowledge (both published and unpublished) for those topics. Information is categorized per habitat/landscape or as global knowledge using the following scale: (0) No Information, (1) Little Information (i.e. information based on a single field season and/or on only a few GHLT groups/individuals), (2) Moderate Information, (3) High Amount of Information (i.e. information based on multiple field seasons and GHLT groups/individuals). Asterisks (^*) indicate that data have been collected but not yet analyzed.

The symposium was concluded with a discussion of how we can fill these major research gaps and how communication between researchers and stakeholders can be improved in order to disseminate the results of research and improve the efficiency of conservation efforts of the species.

Conclusion

We considered this meeting a very significant event because it brought together the majority of researchers involved with the in situ conservation of GHLTs to discuss research and exchange ideas. The resulting overview of existing knowledge and the list of knowledge gaps can serve as guidelines for the development of future research projects that wish to ultimately contribute to the development of conservation actions for the species. With this information, next steps will include reaching out to stakeholders involved with activities relevant to the conservation of the Atlantic Forest in general and GHLTs in particular. It is important that research results presented during this symposium become available to the wider public, particularly to federal and non-governmental institutions and civil society. The format of the distributed information should allow stakeholders to see how their respective activities might affect GHLTs and the landscape in which they reside while suggesting the kind of alterations that may be required to make those activities more compatible with GHLT conservation.

Ultimately, to maximize the long-term persistence of GHLTs, we need to conserve a functionally connected landscape that offers adequate resources and allows GHLTs to move and breed successfully within the exceptionally heterogeneous environment of southern Bahia. Partly, this includes a much better understanding of the anthropogenic pressures on GHLTs and their habitat. Of equal importance is the consideration of GHLTs within their broader ecological network and the Atlantic Forest ecosystem. Studying GHLTs as an integral part of the ecological network of which they are a part will improve our understanding of the species' needs as well as its role within the ecosystem, contributing to more efficient conservation actions in the long-term. To get to this point, critical research is still needed at both broader and narrower scales as described in this document. Broadening our focus to the entire Atlantic Forest while continuing to study essential aspects of the species' biology, is likely the most efficient conservation strategy over the long-term. There is an increasing demand for large-scale projects that focus on regions, their ecological functionality, and the species within those regions. We hope that this document serves as a guideline for how to develop new projects and partnerships that incorporate this demand and contribute to the long-term persistence of GHLTs and the Atlantic Forest.