Working Group on Iberian Lucanidae (GTLI)

Saproxylic organisms depend, during part of their life cycle, on dead or dying wood from standing or fallen dead or dying trees, or on wood fungi or on the presence of other saproxylics (Speight, 1989). Although it is a taxonomically heterogeneous group, insects and particularly beetles are the organisms most represented among saproxylics. it is estimated that between 22 and 56% of forest beetles are saproxylic (Grove, 2002).

Aside of being an important portion of forest biodiversity, saproxylic organisms play a fundamental role in the forest ecosystem. Wood decay is an essential part of the carbon cycle in ecosystems; life as we know it would collapse in 20 years due to lack of atmospheric CO2 if wood decay would stop while photosynthesis would continue at the current rate (Kirk & Cowling, 1984). Thus, the sustained attention paid to saproxyilic insect ecology is not surprising. Dajoz (2000) is a key reference for people interested in this group. A short introduction to saproxylic organisms can be found here (only in Spanish).

A long history of forest use has threatened the survival of many saproxylic insects. Forest destruction, fragmentation and degradation has entailed the extinction or drastic abundance reductions of many saproxylic species (Speight, 1989). In particular, the negative attitude of foresters towards the presence of dead wood in the forest has contributed to declines in saproxylic diversity.

Conservation and efficient management of saproxylic insects requires a good knowledge of their ecology. Although many studies have been carried out in Europe, ecological research on saproxylic insects is still in its infancy in the Iberian Peninsula. Table 0.1 summarizes some of the questions that Iberian forest entomologists must address in order to provide a sound basis to the conservation of Iberian saproxylics. This list can be taken as a tentative research agenda for the study of Iberian saproxylic insects in the coming years.

1. A check-list of Iberian saproxlic species

2. Ecology of target species:

- Habitat specificity
- Quantity and quality of dead wood needed
- Effect of habitat fragmentation
- Threat sources

3. Wood decay succession in Mediterranean environments

4. Role of saproxylic insects in Mediterranean ecosystems

5. Factors influencing saproxylic diversity:

- Dead wood amount
- Type of forest
- Habitat fragmentation
- Forest management
- Fire regime

To answer many of the questions posed in Table 0.1 quantitative sampling methods will be necessary. Only then it will be possible to compare species diversity and abundance across sites, management methods, and so on. es necesario contar con métodos de muestreo cuantitativos, de modo que sea posible comparar la diversidad y abundancia de especies entre sitios, tipos de gestión, etc. We present a list of sampling methods (only in Spanish), including instructions for trap building (only in Spanish).

References

Dajoz, R. (2000). Insects and forests: the role and diversity of insects in the forest environment. Editions Tec & Doc, Paris.

Grove, S. J. (2002). Saproxylic insect ecology and the sustainable management of forests. Annu. Rev. Ecol. Syst. 33: 1-23.

Kirk, T. K.; Cowling, E. B. (1984). Biological decomposition of solid wood. En: Rowell, R. M. (ed.) The chemistry of solid wood: 455-487. American Chemical Society, Washington DC.

Speight, M. C. D. (1989). Saproxylic invertebrates and their conservation. Nature and Environment Series 46, Council of Europe, Strasbourg.