Building wood debris piles benefits avian seed dispersers in burned and logged Mediterranean pine forests
Introduction
Wildfires are one of the most important disturbances affecting ecological processes and economic interests in forest ecosystems worldwide (Blondel and Aronson, 1999, Hessburg and Agee, 2003, FAO, 2007). In many countries postfire salvage logging (i.e., the harvesting of burned timber for mainly commercial purposes) is the most extended forestry practice intended to compensate for the economic losses caused by wildfires (Hutto, 2006, Lindenmayer et al., 2004). Salvage logging is also justified by other objectives, such as reducing the fuel load, enhancing future tree survival, preventing the proliferation of xylophagous insects or making it easier and safer for people to pass through the burned area or for future forest management work to be carried out (Ne’eman et al., 1995, Martínez-Sánchez et al., 1999, Lindenmayer and Noss, 2006).
In the Mediterranean Basin, where there has been a long history of landscape management, fires often take place in lowland pine forests, most of which grow on abandoned agricultural land (Trabaud, 1981). In this type of forest, after a fire, salvage logging is the most frequently used management method, because pine wood is still commercially profitable for use as boards until two years after a fire, and even later if ground down (e.g., to produce biomass fuel). In general terms, salvage logging involves a drastic habitat change—from a burned forest structure to open grassland and shrubland—a short time after the fire. However, on a smaller scale the characteristics of these new open habitats also depend on the interests and decisions of landowners and managers, and therefore on the ownership structure of each burned forest. When forests are divided into small privately owned lots, as is often the case in Mediterranean areas, individual decisions lead to the coexistence of multiple management models in burned stands in close proximity. These strategies result in clearcuts (where wood debris may be completely removed, left on the ground or piled up), areas where isolated snags remain, and unlogged stands of partially burned pines. Furthermore, restoration measures such as log erosion barriers can be found in burned public forests, which are managed essentially for restoration purposes. The administrative authority concerned may also issue management recommendations, and grant subsidies to, or reach agreements with, local landowners, who may then delegate postfire management to public managers.
The habitat disturbance induced by postfire salvage logging affects animal communities, an issue that has sometimes been studied using birds as the focal group (Kotliar et al., 2002, Hutto and Gallo, 2006, Cahall and Hayes, 2009). It has been shown that salvage logging can have a greater impact than the fire itself on the forest bird community, including the substitution of forest specialists by open-land species (Izhaki, 1993, Llimona et al., 1993, Morisette et al., 2002, Castro et al., in press). Such changes are likely to affect frugivorous bird species, some of which are involved in important ecological processes such as seed dispersal of fleshy-fruited shrubs and climbers. In the Mediterranean, fleshy-fruited plants produce ripe fruit during the fall and winter (Mooney and Kummerow, 1981, Jordano, 1992), when various species of small and medium-sized birds disperse their seeds (Herrera, 1984, Herrera, 1998). In burned areas, early succession gives rise to a shrubland-like habitat (Trabaud and Lepart, 1980), which hosts a diverse winter bird assemblage, including some species that attain high densities thanks to postfire fruit and seed production (Pons and Prodon, 1996, Pons, 2001, Tellería et al., 2004). Izhaki and Adar (1997) showed that winter bird communities in eastern Mediterranean burned and logged forests were dominated by shrubland species, some of which were seed dispersers. However, the habitat and microhabitat use of these species under different scenarios of postfire management has not yet been studied in depth. Previous studies have reported that bird-dependent seed rain strongly relies on habitat structures that act as dispersal foci, such as isolated trees that act as perches (Guevara and Laborde, 1993, Pausas et al., 2006, Herrera and García, 2009). After logging, wood debris piles and barriers built in a burned pine forest can also act as dispersal foci (Rost et al., 2009). Thus, the variability of postfire treatments after logging, which leads to the presence of different microhabitats on a small scale, may have important implications for bird-dependent seed rain, depending on the differential use that seed dispersers make of the resulting microhabitats.
The aims of this study are: (1) to investigate the effects of postfire management on winter bird communities in burned Mediterranean pine forests, (2) to determine whether certain management practices have positive effects on species richness and abundance of seed dispersers in winter, and (3) to analyze microhabitat selection by seed dispersers in order to describe patterns in their use of the microhabitats. If postfire management practices had an effect on seed dispersers distribution and microhabitat use, this would also affect seed rain and the regeneration of fleshy-fruit producing shrub or climber species. We took advantage of the availability in three study areas of examples of different postfire logging practices (ranging from completely logged areas to unlogged ones, and including different methods of managing wood debris) to investigate which of these practices may be more favorable to the presence of bird species involved in seed dispersal.
Section snippets
Study area
The study was carried out in three burned areas located in Catalonia, in the northeast of the Iberian Peninsula: Torroella de Montgrí (henceforth TM, 3°7′ E, 42°3′ N), Ventalló (VE, 3°2′ E, 42°7′ N) and Cistella (CI, 2°50′ E, 42°17′ N) (Fig. 1). The maximum distance between any two areas was 30 km. All three areas have a meso-Mediterranean climate, limestone substrates, and altitudes ranging from 80 to 210 m above sea level. Before the fire, they featured a vegetation mosaic composed of Aleppo
Results
In the point counts we recorded a total of 744 birds belonging to 38 species (Table 1). The most abundant species were the Sardinian warbler, the Dartford warbler, the European robin, the Hedge accentor (Prunella modularis) and the Chaffinch (Fringilla coelebs). The seed disperser group is composed by nine species (Table 1), which accounted for 58% of the total abundance, the three most abundant accounting for 48% of the total abundance.
RDA results showed that habitat variables explained 16% of
Discussion
Habitat heterogeneity in burned Mediterranean pine forests allows the coexistence of bird species with different habitat requirements during winter, and thus we found a mixture of open-land, shrubland and forest birds in our study sites. Such habitat and bird community heterogeneity likely results from the management carried out in these areas, as well as from the regeneration of the low plant cover. We found that different management practices favored different bird species in winter. Indeed,
Acknowledgements
The authors would like to thank David Meya and Joan Real for kindly providing us with advice and information. This study was funded by the Spanish Ministry of Science and Innovation (CGL2005-0031/BOS and CGL2008-05506/BOS) and J.R. held a FPU grant of the Ministry of Education.
References (54)
- et al.
Influences of postfire salvage logging on forest birds in the Eastern Cascades, Oregon, USA
Forest Ecol. Manag.
(2009) - et al.
Effects of undergrowth clearing on the bird communities of the Northwestern Mediterranean Coppice Holm oak forests
Forest Ecol. Manag.
(2006) - et al.
The role of remnant trees in seed dispersal through the matrix: being alone is not always so sad
Biol. Conserv.
(2009) - et al.
An environmental narrative of Inland Northwest United States forests, 1800–2000
Forest Ecol. Manag.
(2003) - et al.
Influence of deadwood on density of soil macro-arthropods in a managed oak-beech forest
Forest Ecol. Manag.
(2004) - et al.
Effects on erosion of two postfire management practices: clearcutting versus non-intervention
Soil Till. Res.
(1998) - et al.
Recovery of vegetation in a natural east Mediterranean pine forest on Mount Carmel, Israel as affected by management strategies
Forest Ecol. Manag.
(1995) - et al.
The role of the perch effect on the nucleation process in Mediterranean semi-arid oldfields
Acta Oecol.
(2006) - et al.
Can salvage logging affect seed dispersal by birds into burned forests?
Acta Oecol.
(2009) - et al.
Bird Census Techniques
(1992)
Birds in Europe: population estimates, trends and conservation status
BirdLife Conservation Series No. 12
Biology and Wildlife of the Mediterranean Region
CANOCO Reference Manual and User's Guide to Canoco for Windows. Software for Canonical Community Ordination (Version 4)
Is hábitat management an effective tool for wild rabbit (Oryctolagus cuniculus) population reinforcement?
Eur. J. Wildland Res.
Response of bird communities to silvicultural thinning of Mediterranean maquis
J. Appl. Ecol.
Incendis 1986–2008—Medi Ambient i Habitatge
State of the World's Forests 2007
Saproxylic insect ecology and the sustainable management of forests
Annu. Rev. Ecol. Evol. Syst.
Monitoring seed dispersal at isolated standing trees in tropical pastures—consequences for local species availability
Vegetatio
Changes in rodent community during recovery from fire: relevance to conservation
Biodivers. Conserv.
Postfire forest management and Mediterranean birds: the importance of logging remnants
Biodivers. Conserv.
A study of avian frugivores, bird-dispersed plants, and their interaction in Mediterranean scrublands
Ecol. Monogr.
Plant-vertebrate dispersal systems in the Mediterranean: ecological, evolutionary and historical determinants
Annu. Rev. Ecol. Syst.
Long-term dynamics of Mediterranean frugivorous birds and fleshy fruits: a 12-year study
Ecol. Monogr.
Toward meaningful snag-management guidelines for postfire salvage logging in North American Conifer Forests
Conserv. Biol.
Cited by (31)
Examining the temporal effects of wildfires on forest birds: Should I stay or should I go?
2023, Forest Ecology and ManagementWinter bird use of harvest residues in clearcuts and the implications of forest bioenergy harvest in the southeastern United States
2016, Forest Ecology and ManagementCitation Excerpt :obs.). Similar inter-relationships between downed wood perches and foraging have been recorded for European robin (Erithacus rubecula; Rost et al., 2010) and several Australian robins (Petroica spp.; Mac Nally et al., 2001). Winter bird use of downed wood perches decreased as maximum vegetation height increased from 2013 to 2014, potentially indicating structural height more so than perch type (i.e., downed wood versus vegetation) dictates winter bird perch selection.
Assessing biodiversity and conservation value of forest patches secondarily fragmented by urbanisation in semiarid southeastern Spain
2014, Journal for Nature ConservationCitation Excerpt :For each patch, the mean number of birds recorded per plot (averaged among the two sampling dates) was used as an index of abundance. According to Rost et al. (2010) detectability was expected to correlate with raw abundance, so we are aware that species present in low numbers could have passed undetected in some plots, rendering richness values also indicative. Sampling was carried out by both authors in all cases.
Post-fire wood management alters water stress, growth, and performance of pine regeneration in a Mediterranean ecosystem
2013, Forest Ecology and ManagementCitation Excerpt :Natural inanimate objects offering potential for facilitation include rocks, boulders, terrace risers (Carlucci et al., 2011; Coop and Schoettle, 2009; Peters et al., 2008; Resler et al., 2005; Munguía-Rosas and Sosa, 2008; Smit et al., 2008), piles of cut branches mimicking nurse canopies (Gómez-Aparicio et al., 2005; Padilla and Pugnaire, 2008), or even branches spread on the ground as a result of pruning activity (Castro et al., 2011; Harrington et al., 2013; Hastings et al., 2003; Jacobs and Gatewood, 1999; Stoddard et al., 2008). Moreover, the structural habitats provided by dead logs and branches in disturbed forest areas (whether from fire or other disturbances such as insect outbreaks, droughts, and windstorms) may attract animal seed dispersers, further increasing the positive effects on seedling recruitment (Carlucci et al., 2011; Castro et al., 2010b, 2012; Cavallero et al., 2013; Rost et al., 2009, 2010), and also potentially reducing herbivore damage to the regenerating vegetation (Relva et al., 2009; Ripple and Larsen, 2001). The potential of facilitation by dead tree structures resulting from different disturbances for ecological restoration is very large at the global scale.
Comparing the effect of salvage logging on birds in the Mediterranean Basin and the Rocky Mountains: Common patterns, different conservation implications
2013, Biological ConservationCitation Excerpt :On the other hand, the bird species that have captured most conservationists’ concerns and efforts in Europe in recent decades are those from steppes and farmlands because those species have sharply declined due to habitat loss and degradation (BirdLife International, 2004). Some of these species colonize recently burned areas, apparently benefitting from fire (Pons and Bas, 2005; Brotons et al., 2008) and logging (Castro et al., 2010; Rost et al., 2010). Therefore, differences in the avifauna and conservation priorities in different regions need to be considered when assessing the impact of salvage logging on bird communities.