BUSCADOR RECOLECTA

Background: Little is known about the interaction between predators and wildfires, in part because the large home range and scarcity of predators make their study difficult, and their response is strongly species-specific. Aims: In this paper, we study, for the first time, the effect of wildfire on the behaviour of Bonelli’s eagles (Aquila fasciata) simultaneously tracked by GPS/GSM dataloggers in four neighbouring territories. Methods: One territory was burnt in a wildfire and the other three were used for comparison. We computed the home-range area by comparing individual spatial and temporal behaviour before, during and after the fire event using kernel density estimators and movement parameters. Key results: Our results show an immediate negative effect during the first days of the wildfire for an individual inhabiting the burnt territory – the individual flew directly away from the burning area. However, after a few days, the individual recovered their usual behaviour. The three neighbouring pairs did not show significant differences in behavioural parameters before, during and after the wildfire. Conclusions and implications: Our results suggest that occasional wildfires do not affect the distribution and density of Bonelli’s eagles in the short or medium-term (two years after fire). This could be the result of adaptation by this species to the frequent and recurrent wildfires in the Mediterranean area., This work was supported by Red Eléctrica de España and Wildlife Service of the Valencian Community regional government (Conselleria d’Agricultura, Desenvolupament Rural, Emergència Climàtica i Transició Ecològica, Generalitat Valenciana, Spain). We also thank project FIROTIC (PGC2018-096569-B-I00, Spanish Government).

Premise: Resource availability affects biomass allocation in ways that could influence plant responses to disturbance such as fire. This is important because fire also varies across landscapes in ways that are correlated to resource availability. We hypothesized that plants growing in landscape microsites with a shortage of nutrients and water allocate more biomass and resources to belowground structures (and thus promote traits that enhance post-fire resprouting ability) than plants in more mesic sites. Methods: We selected sites in three contrasting topographies (3 gullies, 3 midslopes, and 3 ridges) that supported different vegetation types and fire regimes, in Jalisco, Mexico. At each site, we measured soil nutrient and water content and light availability. Then we sampled biomass and root starch allocation in three post-fire resprouting shrubs that grow across a wide range of microenvironmental conditions. Results: The ridges showed the highest values of solar radiation and the lowest of soil N and water content. Overall, we found a significant tendency for higher root-to-shoot (R/S) ratios, greater fine root biomass, and higher root starch content, in individuals growing in ridges or midslopes compared to the values of the plants living in gullies. Conclusions: Plants located in open canopy sites, characterized by a shortage of nutrients and water, tend to allocate more biomass belowground than plants in wet and fertile sites. Thus, plants in wet and fertile forests should be more vulnerable to increased disturbance such as wildfires., CONACYT. Grant Number: 635743/337325 University of Guadalajara Spanish Government. Grant Number: PGC2018‐096569‐B‐I00 Generalitat Valenciana. Grant Number: PROMETEO/2016/021, Peer reviewed

© 2021 The Authors., It is common to characterise the species niche using climate and global species distribution maps. This is then used to predict changes in distribution under a warming climate. This approach assumes that climate is a major driver of species distribution and that each species responds individually (sensu Gleason) to climate. However, in many world landscapes, for a given climate, strikingly different vegetation types co-occur: forests and non-forests. These two alternative biome states are maintained by different feedback processes and have radically different species with contrasting shade and disturbance tolerance traits. We propose that to improve predictions of species distribution changes under a novel climate, we need to consider the presence or absence of forest shade, as species are likely to respond individually only within their forest or non-forest biome, and not across biomes. Synthesis. By considering shade as a biotic filter in niche modelling, we are not only improving our predictive capacity, but we are also reconciling the two views of communities: both the individualistic (within biome) and the organismal (across biomes) views of the community concept become relevant and complementary., This research has been performed under the framework of the projects FIROTIC (PGC2018-096569-B-I00, Spanish government).

The evolutionary role of fire in animals has been poorly explored. Reptiles use sensory cues, such as smell (chemoreception), to detect threats and flee. In Mediterranean ecosystems, fire is a threat faced by reptiles. We hypothesized that the Mediterranean lizard Psammodromus algirus recognizes the threat of fire by detecting the smoke, which triggers a behavioral response that enhances survival in fire-prone ecosystems. We predicted that lizards from fire-prone ecosystems will be more sensitive to fire stimulus than those from ecosystems that rarely burn. We conducted a terrarium experiment in which lizards from habitats with contrasted fire regimes (fire-prone vs. non-fire-prone) were exposed to smoke versus control (false smoke) treatment. We found that, in populations from fire-prone habitats, more lizards reacted to smoke, and their behavioral response was more intense than in lizard populations from non-fire-prone habitats. Our results suggest that an enhanced response to smoke may be adaptive in lizards from fire-prone ecosystems as it increases the chance for survival. We provide evidence that fire is likely an evolutionary driver shaping behavioral traits in lizard populations exposed to frequent wildfires. Understanding ecological and evolutionary processes shaping animal populations is relevant for species conservation in a changing fire regime world., This work was supported by the Ministry of Economy and Competitiveness and the Ministry of Science, Innovation and Universities of the Spanish Government (grant numbers CGL2015-64086-P, PGC2018-096569-B-I00, and BES-2016–078225)

Wildfires are a natural disturbance in many ecosystems. However, their effect on biotic interactions has been poorly studied. Fire consumes the vegetation and the litter layer where many parasites spend part of their life cycles. We hypothesize that wildfires reduce habitat availability for parasites with consequent potential benefits for hosts. We tested this for the lizard Psammodromus algirus and its ectoparasites in a Mediterranean ecosystem. We predicted that lizards in recently burned areas would have lower parasite load (cleaning effect) than those in unburned areas and that this phenomenon implies that lizards spending their entire lives in postfire conditions experience a lower level of parasitism than those living in unburned areas. We compared the ectoparasite load of lizards between eight paired burned/unburned sites, including recent (less than 1 year postfire) and older fires (2-4 years). We found that lizards' ectoparasites prevalence was drastically reduced in recently burned areas. Likewise, lizards in older burned areas showed less evidence of past parasitic infections. Fire disrupted the host-parasite interaction, providing the opportunity for lizards to avoid the negative effects of ectoparasites. Our results suggest that wildfires probably fulfil a role in controlling vector-borne diseases and pathogens, and highlight ecological effects of wildfires that have been overlooked., This work was supported by Ministry of Economy and Competitiveness and Ministry of Science, Innovation and Universities from the Spanish Government (grant nos CGL2015-64086-P, PGC2018-096569-B-I00, BES-2016-078225).

No single factor produces wildfires; rather, they occur when fire thresholds (ignitions, fuels, and drought) are crossed. Anomalous weather events may lower these thresholds and thereby enhance the likelihood and spread of wildfires. Climate change increases the frequency with which some of these thresholds are crossed, extending the duration of the fire season and increasing the frequency of dry years. However, climate-related factors do not explain all of the complexity of global fire-regime changes, as altered ignition patterns (eg human behavior) and fuel structures (eg land-use changes, fire suppression, drought-induced dieback, fragmentation) are extremely important. When the thresholds are crossed, the size of a fire will largely depend on the duration of the fire weather and the extent of the available area with continuous fuels in the landscape., This work was performed under the framework of the FIROTIC project (PGC2018-096569-B-I00) of the Spanish Government and the PROMETEO/2016/021 project of Generalitat Valenciana.

[Methods] We selected 13 sites dominated by Pinus halepensis trees in the Valencia region (eastern Spain) across a range of altitudes and climatic conditions. In each site, we established 4 transects, spaced by at least 100 m. In each transect, we haphazardly selected and georeferenced 10 trees, separated by at least 10 m. For each tree, we measured its basal diameter (10 cm above ground) and the distance to the two closest trees. Then, we compute the annual growth rate as the basal diameter (cm) divided by the age (years) and the average of the distances to the 2 closest trees. Afterward, we estimated the age of each tree by counting whorls. For reproductive trees, we also estimated the age of each cone following the same method of counting whorls (avoiding immature cone cohorts; i.e., the last or last two cohorts depending on the sampling season) and recorded whether they were open (non-serotinous), closed (serotinous cones), or from the last cohort considered (closed but serotiny unknown). The retention of branches and cones in this species allowed us to estimate the age of the young tree and its cones (even if they were open), and therefore the age at first reproduction (tree age - age of the first cone) and the total number of stored cones (i.e. closed cones; an estimation of the canopy seed bank) for each tree. Please see “materials and methods” section within the paper for more details., Wildfires are a natural disturbance in many ecosystems. Consequently, plant species have acquired traits that allow them to resist and regenerate in an environment with recurrent fires. A key trait in fire-prone ecosystems is the age at first reproduction (maturity age); populations of non-resprouting species cannot persist when fire interval is shorter than this age. Maturity age is variable among individuals, so we hypothesize that short fire intervals select for early seed production (precocity). We selected 13 plots with different fire regimes in eastern Spain, all dominated by Pinus halepensis (a non-resprouting serotinous species). Then, we evaluated the age at first reproduction and the size of the canopy seed bank of each individual pine. Our results show a significant effect of fire regime on the onset of reproduction in this species, suggesting a selection towards higher precocity in populations subject to shorter fire intervals. Due to this higher precocity, pines stored more cones, and therefore, increased their potential for post-fire regeneration. We provide the first field evidence that fire can act as a driver of precocity. Being precocious in fire-prone environments is adaptive because it increases the probability of having a significant seed bank when the next fire arrives., Ministerio de Ciencia e Innovación, Award: PGC2018-096569-B-I00. Ministerio de Ciencia e Innovación, Award: FPU16/06412., Peer reviewed

Ecology and evolutionary biology have focused on how organisms fit the environment. Less attention has been given to the idea that organisms can also modify their environment, and that these modifications can feed back to the organism, thus providing a key factor for their persistence and evolution. There are at least three independent lines of evidence emphasizing these biological feedback processes at different scales: niche construction (population scale); alternative biome states (community scale); and the Gaia hypothesis (planetary scale). These feedback processes make us rethink traditional concepts like niche and adaptation. We argue that organism–environment feedbacks must become a regular part of ecological thinking, especially now that the Earth is quickly changing., This research has been performed under the framework of the projects FIROTIC (PGC2018-096569-B-I00, Spanish government) and FocScales (Promteo/2021/040, Generalitat Valenciana)., Peer reviewed

Extreme climate events, together with anthropogenic land-use changes, have led to the rise of megafires (i.e., fires at the top of the frequency size distribution) in many world regions. Megafires imply that the center of the burnt area is far from the unburnt; therefore, recolonization may be critical for species with low dispersal abilities such as reptiles. We aimed to evaluate the effect of megafires on a reptile community, exploring to what extent reptile responses are spatially shaped by the distance to the unburnt area. We examined the short-term spatiotemporal response of a Mediterranean reptile community after two megafires (>20,000 ha) that occurred in summer 2012 in eastern Spain. Reptiles were sampled over 4 years after the fire in burnt plots located at different distances from the fire perimeter (edge, middle, and center), and in adjacent unburnt plots. Reptile responses were modeled with fire history, as well as climate and remotely sensed environmental variables. In total, we recorded 522 reptiles from 12 species (11 species in the burnt plots and nine in the unburnt plots). Reptile abundance decreased in burnt compared with unburnt plots. The community composition and species richness did not vary either spatially (unburnt and burnt plots) or temporally (during the 4 years). The persistence of reptiles in the burnt area supported their resilience to megafires. The most common lizard species was Psammodromus algirus; both adults and juveniles were found in all unburnt and burnt plots. This species showed lower abundances in burnt areas compared with the unburnt and a slow short-term abundance recovery. The lizard Psammodromus edwarsianus was much less abundant and showed a tendency to increase its abundance in burnt plots compared with unburnt plots. Within the megafire area, P. algirus and P. edwarsianus abundances correlated with the thermal–moisture environment and vegetation recovery regardless of the distance from the fire edge. These results indicated the absence of a short-term reptile recolonization from the unburnt zone, demonstrating that reptiles are resilient (in situ persistence) to megafires when environmental conditions are favorable., FCT, Fundaçao para a Ciência e a Tecnologia, Portugal, Grant/Award Number: CEECIND/02331/2017/CP1423/ CT0012; Ministerio de Ciencia, Innovacion y Universidades, Gobierno de España, Grant/Award Number: PGC2018-096569-B-I00; Ministerio de Economía, Industria y Competitividad, Gobierno de España, Grant/Award Number: CGL2015-64086-P, Peer reviewed

Tropical forests and savannas can co-occur in a range of macro-environmental conditions. In these conditions, disturbances and resource availability are thought to control savanna and forest transitions, although the mechanisms involved are disputed. We hypothesized that, in Neotropical regions where fire activity is high, fire is the main factor controlling functional differences between savanna and forest, as well as their relative resistance to biome shifts. We sampled plant functional traits and soil and determined fire history, for 198 plots distributed across three landscapes with distinct fire frequencies (high, mid, and low). In each landscape, plots covered a woody cover gradient (from wooded grasslands to forests). We tested whether the sharpness and the magnitude of the functional distinction between savanna and forest were affected by fire. We also computed the environmental hyperspace (niche space) to evaluate how biome relative stability changed in relation to fire. Functional thresholds were detected only in the high and mid landscapes, where savanna and forest plots formed a multidimensional bimodal distribution in functional trait space. The stability of savannas in relation to forest increased abruptly with fire, whereas functional differences between forest and savanna increased gradually. Our results suggest that savanna can occur as an alternative vegetation state to forest where a fire burns every 18 years (on average), but higher frequencies are required for savannas to occupy large unique portions of the environmental niche space., The authors are grateful to the São Paulo Research Foundation (FAPESP; processes 2013/50169-1, 2014/06100-0, and 2014/06453-0) for the financial support and scholarships granted to the authors. This study was financed in part by the Coordenação de Aperfeiçoamento de Pessoal de Nível Superior—Brasil (CAPES)—Finance Code 001. M.H. is currently supported by a grant from Instituto Serrapilheira/Serra-1709-18983, R.O. by a Grant from FAPESP 19/07773-1, and J.P. by a Grant from the Spanish government (PGC2018-096569-B-I00).

Seed dormancy varies greatly between species, clades, communities, and regions. We propose that fireprone ecosystems create ideal conditions for the selection of seed dormancy as fire provides a mechanism for dormancy release and postfire conditions are optimal for germination. Thus, fire-released seed dormancy should vary in type and abundance under different fire regimes. To test these predictions, we compiled data from a wide range of fire-related germination experiments for species in different ecosystems across the globe. We identified four dormancy syndromes: heat-released (physical) dormancy, smoke-released (physiological) dormancy, non-fire-released dormancy, and non-dormancy. In fireprone ecosystems, fire, in the form of heat and/or chemical by-products (collectively termed ‘smoke’), are the predominant stimuli for dormancy release and subsequent germination, with climate (cold or warm stratification) and light sometimes playing important secondary roles. Fire (heat or smoke)-released dormancy is best expressed where woody vegetation is dense and fires are intense, i.e. in crown-fire ecosystems. In such environments, seed dormancy allows shade-intolerant species to take advantage of vegetation gaps created by fire and synchronize germination with optimal recruitment conditions. In grassy fireprone ecosystems (e.g. savannas), where fires are less intense but more frequent, seed dormancy is less common and dormancy release is often not directly related to fire (non-fire-released dormancy). Rates of germination, whether controls or postfire, are twice as fast in savannas than in mediterranean ecosystems. Fire-released dormancy is rare to absent in arid ecosystems and rainforests. The seeds of many species with fire-released dormancy also possess elaiosomes that promote ant dispersal. Burial by ants increases insulation of seeds from fires and places them in a suitable location for fire-released dormancy. The distribution of these dormancy syndromes across seed plants is not random – certain dormancy types are associated with particular lineages (phylogenetic conservatism). Heat-released dormancy can be traced back to fireprone floras in the ‘fiery’ mid-Cretaceous, followed by smoke-released dormancy, with loss of fire-related dormancy among recent events associated with the advent of open savannas and non-fireprone habitats. Anthropogenic influences are now modifying dormancy-release mechanisms, usually decreasing the role of fire as exaptive effects. We conclude that contrasting fire regimes are a key driver of the evolution and maintenance of diverse seed dormancy types in many of the world's natural ecosystems., J.G.P.s contribution to this study was performed within the framework of projects FocScales (PROMETEO/2021/040; Generalitat Valenciana) and FIROTIC (PGC2018-096569-B-I00; Spanish government); B.B.L.s contribution was privately supported.

Seed dormancy (i.e. delayed germination even when conditions arefavourable) is a key plant characteristic that occurs among manyspecies worldwide. But, what selective pressures led to seeddormancy? A recent study provides a major analysis of the factorsdriving this trait at the global scale (Zhanget al.,2022). Usingc.12 000 species and 10 million records across the globe, theyconclude that dormancy is a strategy for plants living under‘seasonal/unpredictable’ environments; and suggest that bet-hedg-ing could be the major mechanism behind the pattern. To reachtheir conclusions the authors relate the proportion of species withdormant seeds in a grid-cell global map against climate variablesrelated to annual precipitation, temperature and seasonality. Thenthey showed that the most significant variables were those related toclimate seasonality that they equate with unpredictable climates(although seasonal climates usually are highly predictable in theirseasonal cycles)., This research was performed under the framework of projects FIROTIC (PGC2018-096569-B-I00; Spanish government, MCIN/AEI/10.13039/501100011033 and FEDER) and FocScales (Promteo/2021/040, Generalitat Valenciana)., Peer reviewed

Wildfires are a natural disturbance in many ecosystems. Consequently, plant species have acquired traits that allow them to resist and regenerate in an environment with recurrent fires. A key trait in fire-prone ecosystems is the age at first reproduction (maturity age); populations of non-resprouting species cannot persist when the fire interval is shorter than this age. Maturity age is variable among individuals, so we hypothesized that short fire intervals select for early seed production (precocity). We selected 13 plots with different fire regimes in eastern Spain, all dominated by Pinus halepensis (a non-resprouting serotinous pine species). Then, we evaluated the age at first reproduction and the size of the canopy seed bank of each individual tree. Our results show a significant effect of fire regime on the onset of reproduction in this species, suggesting a selection towards higher precocity in populations subject to shorter fire intervals. Due to this higher precocity, pines stored more cones and therefore, increased their potential for reproduction post-fire. We provide the first field evidence that fire can act as a driver of precocity. Being precocious in fire-prone environments is adaptive because it increases the probability of having a significant seed bank when the next fire arrives., This work has been supported by a research project (FIROTIC, PGC2018-096569-B-I00) and a fellowship (FPU16/06412), both from the Ministry of Science and Innovation from the Spanish Government.

Many animals survive wildfires; however, the mechanisms used to detect and respond to fire have been poorly studied. Sensory cues like sight and sound are used to recognize threats (e.g. predators) and elicit escape responses in prey. Similarly, these cues might be used to detect an approaching wildfire. We tested whether the western fence lizard, Sceloporus occidentalis, responds to the sound of fire as a threat. We predicted that lizards living in burned areas would be more sensitive to the sound of fire than lizards in adjacent and urban areas, where fire suppression could have induced relaxed selection on fire responsiveness. We compared the behaviours of lizards following an experimental playback where we broadcast the sound of fire along with other control sounds (a predator, a common nonpredatory bird and a novel nonpredatory bird). We conducted our playbacks in 2019 in recently burned areas (using the survivors from the 2018 Woolsey Fire, southern California, U.S.A.), unburned adjacent areas and urban areas. We found that in burned areas, lizards responded more to the sound of fire than all three controls, but in urban areas, they responded more to both the sound of a predator and the sound of fire. Our results suggest that lizard responses to fire sounds are greater in an area that has recently experienced a wildfire than in an unburned area, and that urban areas create a complex evolutionary landscape that also increased antipredator behaviour for other biologically relevant stimuli., This work was supported by Ministry of Economy and Competitiveness and Ministry of Science, Innovation and Universities from the Spanish Government (grant numbers CGL2015-64086-P, PGC2018-096569-B-I00 and BES-2016-078225).