Opendata, web and dolomites

Report

Teaser, summary, work performed and final results

Periodic Reporting for period 1 - Diversity6continents (Ecological determinants of tropical-temperate trends in insect diversity)

Teaser

This research aims to explain why tropical rainforest ecosystems support such an extraordinary plant and animal diversity, while temperate zone forests are comparatively impoverished. This tropical – temperate difference is one of the most striking features of global...

Summary

This research aims to explain why tropical rainforest ecosystems support such an extraordinary plant and animal diversity, while temperate zone forests are comparatively impoverished. This tropical – temperate difference is one of the most striking features of global distribution of biota and as such needs to be understood and explained – for the curiosity’s sake, since we want to understand the world we are living in, as well as for better biodiversity conservation and maintenance of biodiversity-related ecosystem services. Our project examines plant – insect food webs in forest ecosystems in a global network of six study sites, representing three tropical – temperate pairs located at different continents. The study of plant and insect communities, and their interactions, is designed to reveal whether the diversity of insects can be fully explained by plant diversity alone. This would have important consequences for our strategies of biodiversity conservation, suggesting a strong focus on the vegetation. Further, the study will help us understand how approximately six million insect species, most of them still unknown to science, can coexist in tropical forests. The project includes a significant research infrastructure – a crane allowing access to rainforest canopy built in Papua New Guinea.

Work performed

The project is ahead of schedule, both in terms of field work and analysis. We have completed one year of sustained sampling of food webs using canopy crane of the Smithsonian Tropical Research Institute in Panama, and also completed a full vegetation season of sampling in the temperate zone forests at Front Royal (USA), working there with the Smithsonian Institution. In Panama, we have sampled two 0.1 ha plots of lowland rainforest at San Lorenzo, surveying entire foliage area in the forest for (i) herbivory damage,(ii) free feeding, semi-concealed and mining herbivorous larvae, and (iii) vegetation composition. We have reared the herbivorous insects into adults or parasitoids, and tested them for feeding on the plants they were collected from in no-choice experiments. Likewise, we have completed similar sampling within 0.1 ha plot in the temperate forest at Front Royal in USA, spreading the sampling throughout the vegetation season. We are presently processing our specimens and herbivory data from these sites. In Papua New Guinea, we have surveyed herbivores using this protocol from rainforest understorey along elevation gradient at Mt. Wilhelm. We have also progressed with the analysis of analogous pre-existing data on food webs from the Czech Republic, Japan and Papua New Guinea.

We have contributed to a global analysis of latitudinal trends in predation pressure on insect herbivores, using dummy caterpillars made of plasticine, exposed on vegetation across the globe. The study revealed increasing predation pressure from temperate to tropical ecosystems, and also from lowlands to higher elevations. Both trends were driven by increasing predation by invertebrates, particularly ants, while the predation by birds did not exhibit marked latitudinal or altitudinal trends (Roslin et al. 2017, Science 356: 742).

Our study of temperate zone food webs (Volf et al. 2017, J. Anim. Ecol. 86: 556) used a new method of phylogenetic analysis of host specialization. We showed that not all levels of host plant phylogeny are equal in their effect on structuring plant-herbivore food webs. In the case of generalist guilds, it is the phylogeny of deeper plant lineages that drives the food web structure whereas the terminal relationships play minor roles. In contrast, the specialization and abundance of monophagous guilds are affected mainly by the terminal parts of the plant phylogeny and do not generally reflect deeper host phylogeny.

In the preparation for the construction of the canopy crane in PNG, we have decided on its location, negotiated necessary land permissions, and set up public selection procedure for the contractors to build the crane. Further, we have surveyed the existing global network of canopy cranes and their contributions to the forest ecology so far. This analysis has contributed to a high-level review of forest canopy science (Nakamura et al. 2017, TREE 32: 438).

These results build a solid foundation for addressing the more general problems of ecological and phylogenetic factors determining latitudinal trends in food web structure, planned for the next stage of the project.

Final results

The project has brought important training benefits at several institution. We engaged two interns and 10 volunteers at the Smithsonian Institution in USA and two interns and two technicians at the Smithsonian Tropical Research Institute for long-term field and laboratory work and training. Further, we trained 15 paraecologists and 20 field assistants hired from indigenous communities in Papua New Guinea. The employment and training of these paraecologists and assistants had direct impact on living standards of under-privileged communities (subsisting on less than EUR 5.00 per person and day). It also contributed to rainforest conservation, since we employed indigenous rainforest owners, demonstrating to them economic benefits associated with forest research and conservation.

The project has also had a relatively high profile in the popularization of science, as its Papua New Guinea part of research was prominently featured at an exhibition at the Naprstek Museum of Asian, African and American Cultures in Prague. The project’s PI also had a one-hour TV interview in prime time on the Czech TV (https://tinyurl.com/hydeTV). Finally, there was a broad media coverage of the Science paper on dummy caterpillar predation in popular science media (https://tinyurl.com/dummycats) as the simple use of children’s toy plasticine for ecological science seems to have captured imagination of the general public.

Website & more info

More info: http://www.entu.cas.cz/png/erc/.