Facundo J. Oddi

Effects of fire severity on early recovery of Patagonian steppes

Fire severity influences the recovery and biodiversity of plant communities. We compared the early post-fire recovery of plant functional groups in two sites (one burnt with high severity and one with low severity) in the north-western Patagonian steppe. We sampled the post-fire soil seed banks, as well as the composition and cover of aboveground plant species, and calculated richness, diversity and the percentage of exotic species. Low fire severity increased the diversity of aboveground vegetation and seed banks, whereas high fire severity reduced the cover of all functional groups, with the exception of fugitive species. Tiller production of perennial grasses decreased due to bud bank mortality. In the seed bank, high severity fire reduced fugitive species and increased exotic species. Fugitive species need fire to recruit, and the combination of fire cues and post-fire environmental conditions can explain the high abundance of these species after fire. In Patagonia, the use of fire is not considered a management option because fires are believed to be dangerous to humans, goods and services. However, north-western Patagonia is sparsely populated and the frequent wildfires pose no danger. It is necessary to increase the knowledge of the ecological processes of Patagonian ecosystems related to fire regime and land use, to achieve a reasonable balance between sustainable use and conservation in this region.

From leaves to landscape: A multiscale approach to assess fire hazard in wildland-urban interface areas.

The overlapping zone between urbanization and wildland vegetation, known as the wildland urban interface (WUI), is often at high risk of wildfire. Human activities increase the likelihood of wildfires, which can have disastrous consequences for property and land use, and can pose a serious threat to lives. Fire hazard assessments depend strongly on the spatial scale of analysis. We assessed the fire hazard in a WUI area of a Patagonian city by working at three scales: landscape, community and species. Fire is a complex phenomenon, so we used a large number of variables that correlate a priori with the fire hazard. Consequently, we analyzed environmental variables together with fuel load and leaf flammability variables and integrated all the information in a fire hazard map with four fire hazard categories. The Nothofagus dombeyi forest had the highest fire hazard while grasslands had the lowest. Our work highlights the vulnerability of the wildland-urban interface to fire in this region and our suggested methodology could be applied in other wildland-urban interface areas. Particularly in high hazard areas, our work could help in spatial delimitation policies, urban planning and development of plans for the protection of human lives and assets.

Fire regime from 1973 to 2011 in north-western Patagonian grasslands

Fire is one of the most important disturbances in terrestrial ecosystems and has major ecological and socioeconomic impacts. Fire regime describes the variation of individual fire events in time and space. Few studies have characterised the fire regime in grasslands in spite of the importance of these ecosystems. The aim of this study was to describe the recent fire regime (from 1973 to 2011) of north-western Patagonian grasslands in terms of seasonality, frequency and burned area. Our study area covered 560 000 ha and we used a remote sensing approach combined with statistics obtained from operational databases. Fires occur during the summer in 2 of every 3 years with a frequency of 2.7 fires per year and a mean size of 823 ha. Fire size distribution is characterised by many small fires and few large ones which would respond to a distribution from the power law family. Eighty per cent of the total area affected by fire was burned in the span of a few years, which were also widespread fire years in forests and woodlands of north-western Patagonia. This work contributes to general knowledge about fire regimes in grasslands and we expect that our results will serve as a reference to further fire regime research.

Perspectives from the Survey of Honey Bee Colony Losses During 2015–2016 in Argentina

Several countries have carried out surveys of managed honeybee colonies, the results of which suggest high loss rates all over the world. Although Latin America is an important apicultural region, estimates of honeybee colony losses are lacking. This study quantified colony losses in Argentina during the 2015-16 season. Overall, the survey included 28,204 honeybee colonies, of which 15.5% were recorded as lost. The total winter losses (13.0%) were higher than summer losses (3.9%), a result that contrasts with that collected in Uruguay where no seasonality was observed in the 2013-14 losses. Although interesting, such inter-country variability cannot be analysed for Latin America because of the lack of simultaneous and standardized estimates of colony losses. Therefore, we developed a unified questionnaire to simultaneously record colony losses in 10 countries of Latin America in collaboration with 35 researchers. We address the readers of Bee World and ask them to help distribute the questionnaire among potentially interested parties in Latin America. (Less)