Aim Savannas and seasonally-dry ecosystems cover a significant part of the world's land surface. If undisturbed, these ecosystems might be expected to show a net uptake of methane (CH 4 ) and a limited emission of nitrous oxide (N 2 O). Land management has the potential to change dramatically the characteristics and gas exchange of ecosystems. The present work investigates the contribution of warm climate seasonally-dry ecosystems to the atmospheric concentration of nitrous oxide and methane, and analyses the impact of land-use change on N 2 O and CH 4 fluxes from the ecosystems in question.Location Flux data reviewed here were collected from the literature; they come from savannas and seasonally-dry ecosystems in warm climatic regions, including South America, India, Australasia and Mediterranean areas.Methods Data on gas fluxes were collected from the literature. Two factors were considered as determinants of the variation in gas fluxes: land management and season. Land management was grouped into: (1) control, (2) 'burned only' and (3) managed ecosystems. The season was categorized as dry or wet. In order to avoid the possibility that the influence of soil properties on gas fluxes might confound any differences caused by land management, sites were grouped in homogeneous clusters on the basis of soil properties, using multivariate analyses. Inter-and intra-cluster analysis of gas fluxes were performed, taking into account the effects of season, land management and main vegetation types.Results Soils were often acid and nutrient-poor, with low water retention. N 2 O emissions were generally very low (median flux 0.32 mg N 2 O m )2 day )1 ), and no significant differences were observed between woodland savannas and managed savannas. The highest fluxes (up to 12.9 mg N 2 O m )2 day )1 ) were those on relatively fertile soils with high air-filled porosity and water retention. The effect of season on N 2 O production was evident only when sites were separated in homogeneous groups on the basis of soil properties. CH 4 fluxes varied over a wide range ()22.9 to 3.15 mg CH 4 m )2 day )1 , where the negative sign denotes removal of gas from the atmosphere), with an annual average daily flux of )0.48 ± 0.96 (SD) mg CH 4 m )2 day )1 in undisturbed (control) sites. Land-use change dramatically reduced this CH 4 sink. Managed sites were weak sinks of CH 4 in the dry season and became sources of CH 4 in the wet season. This was particularly evident for pastures. Burning alone did not reduce soil net CH 4 oxidation, but decreased N 2 O production.Main conclusions Despite the low potential for N 2 O production, both in natural and managed conditions, tropical seasonally-dry ecosystems represent a significant source of N 2 O (4.4 Tg N 2 O year )1 ) on a global scale, as a consequence of the large area they occupy. The same environments represent a potential CH 4 sink of 5.17 Tg CH 4 year )1 . However, assuming that c. 30% of the tropical land is

Abstract. Bryophyte dynamics after fire in the Mediterranean macchia of Southern Italy was studied both by diachronic and synchronic approaches. Changes of bryophyte cover and species composition were found in relation to both age and fire intensity. During the first 2 yr after fire, bryophytes dominated the plots which had experienced the highest fire intensity while herbs were dominant in plots affected by lighter fires. Pioneer species, such as Funaria hygrometrica, Barbula convoluta and Bryum dunense, characterized recent intense fires, whereas Bryum torquescens, B. radiculosum and B. ruderale were dominant after less intense burning. Pleurochaete squarrosa, Tortula ruraliformis and Tortella flavovirens dominated intermediate successional stages. Pleurocarpous mosses were dominant only in the older closed stands. Different patterns of regeneration strategies were described: spores dominated early stages of intense fire, while vegetative propagules characterized later successional stages and less severely burned areas. Although bryophytes usually have a low abundance in Mediterranean vegetation, their role in post‐fire vegetation dynamics may be locally enhanced according to burning conditions.

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"The New Red List of the Italian Flora" includes all the Italian policy species and other species of known conservation concerns for a total of 400 taxa, 65% of which are threatened with extinction. The Red List is based on a huge georeferenced data-set useful for conservation purposes