Aridity influences the recovery of vegetation and shrubland birds after wildfire

Wildfires play a determining role in the composition and structure of many plant and animal communities. On the other hand, climate change is considered to be a major driver of current and future fire regime changes. Despite increases in drought in many areas of the world, the effects of aridity on post-fire colonization by animals have been rarely addressed. This study aims to analyse how a regional aridity gradient affects post-fire recovery of vegetation, bird species richness and the numbers of four early to middle-successional warbler species associated with the shrub cover. The database contains bird relative abundance and environmental variables from 3072 censuses in 695 transects located in 70 recently burnt areas (1 to 11 years after wildfire) in Catalonia (Spain), which were sampled between 2006 and 2013. Generalized linear mixed models (GLMMs) showed that plant cover was affected by time since fire, aridity and forest management. However, only the highest vegetation height layer (>100 cm) recovered slower in arid areas after fire. Time since fire positively influenced bird species richness and the relative abundance of the four focal species. The post-fire recovery of Melodious (Hippolais polyglotta) and Subalpine warblers (Sylvia cantillans) was hampered by aridity. Although this was not demonstrated for Dartford (S. undata) and Sardinian warblers (S. melanocephala), their occurrence was low in the driest areas during the first three years after fire. Overall, this study suggests that future increases in aridity can affect plant regeneration after fire and slow down the recovery of animal populations that depend on understorey and shrublands. Given the recently highlighted increases in aridity and fire frequency in Mediterranean-climate regions, improved knowledge on how aridity affects ecological succession is especially necessary

A comprehensive but practical methodology for selecting biological indicators for long-term monitoring.

The selection of the many biological indicators described in scientific literature is rarely based on systematic or clear-cut processes, and often takes into account only a single or very few taxa, or even disregards the complex interactions that exist between the components of biodiversity. In certain cases, the particular context of a site-for example in the Mediterranean Basin-makes it difficult to apply the choice of indicators to other regions proposed in the literature. Therefore, the selection of appropriate methodologies for generating relevant indicators for a particular site is of crucial importance. Here, we present a simple quantitative methodology capable of incorporating multidisciplinary information for assessing and selecting appropriate methods and indicators for monitoring local biodiversity. The methodology combines several ecological levels (species, habitats, processes, and ecosystem disturbances), and embraces biological interactions and common functional guilds (detritivores, producers, herbivores, and carnivores). We followed an iterative selection procedure consisting of five phases: 1) collection focal area useful information; 2) classification of this information into interrelated datasets; 3) assessment and selection of the relevant components using a quantitative relevance index; 4) the adding of taxonomic, physiognomic and functional similarities to the relevant components; and 5) the quantitative selection of the priority indicators in the study area. To demonstrate the potential of this methodology, we took as a case study the biodiversity components and their ecological interactions present in a protected area. We show that our methodology can help select appropriate local and long-term indicators, reduce the number of components required for thorough biodiversity monitoring, and underline the importance of ecological processes

Anàlisi dels factors determinants en la rebrotada del bruc boal (Erica arborea L.) després de l’incendi de l’Alt Empordà del 2012

S’han analitzat els factors determinants en el procés de rebrotada del bruc boal (Erica arborea) entre quatre i nou mesos després de l’incendi de l’Alt Empordà del 2012.Mitjançant models lineals generalitzats mixtos (GLMM) s’han analitzat quines variables (severitat del foc i altres variables biològiques) han influït en els indicadors de la rebrotada: la biomassa i el creixement dels rebrots. D’una banda, la biomassa s’ha vist influïda pels efectes de l’àrea de la rabassa i pel nombre i l’alçada dels rebrots. De l’altra, una severitat més gran del foc ha promogut el creixement dels rebrots en els primers quatre mesos després de l’incendi, tot i que en els cinc mesos següents s’ha donat l’efecte contrari. En canvi, a baixes severitats, el creixement inicial ha estat menor, incrementant-se en el segon període. La capacitat de resposta d’una espècie dominant, com el bruc, facilita la recuperació de l’ecosistema i s’ha de tenir en compte en la gestió postincendi.This study analyses the key factors in the resprouting process of the tree heath (Erica arborea) between four and nine months after a huge wildfire in Alt Empordà (Catalonia, Spain) in 2012. Generalized linear mixed models (GLMM) were used to analyse which variables (fire severity and other biological variables) affected the biomass and growth of resprouts, indicators of resprouting vigour. On the one hand, biomass was influenced by the lignotuber area and by the number and height of resprouts. On the other hand, a greater fire severity promoted the growth of resprouts in the first four months after the fire, although in the following five months it produced the opposite effect. However, at low severity, initial growth was lower, and it increased in the following period. The response capacity of a dominant species like the tree heath facilitates the recovery of the ecosystem and should be taken into account in post-fire management

Cicada-MET: an efficient ecological monitoring protocol of cicada populations

Cicadas are a fascinating group of insects that play an essential role in terrestrial ecosystems. Their long-lasting association with plant roots encourages their use as indicators of vegetation and soil integrity. Cicada-MET is a novel, standardized method for monitoring cicada populations by counting cicada exuviae (i.e., the skin of emerged nymphs), providing an effective and efficient means to study their distribution, abundance, and ecology. The method involves annual exuviae counts along transects and fixed plots sampled throughout the emergence season. We validated Cicada-MET using a database of 466 counts from 64 transects over 10 years and the sampling of 60 plots for one season. Methodological aspects tested included sampling speed, exuviae detectability in successive counts, exuviae loss due to weather, and cicada species detection performance using exuviae counts compared to auditory methods. Transects captured approximately 10% of the total number of emerged nymphs across one season, demonstrating the protocol’s reliability in estimating emerging cicada population numbers. However, caution is needed when inferring densities for larger areas, separated from paths where transects are located. The standardized nature of Cicada-MET reduces spatial and temporal biases, allowing for interspecific comparisons and monitoring interannual variations in abundances and emergence timing. This method is well-suited for studying the impact of natural and anthropogenic disturbances. The high-resolution data obtained can be easily combined with environmental variables, enhancing the value of cicada data as bioindicators. In summary, Cicada-MET offers a versatile and efficient tool for monitoring cicada populations, with applications in ecological indication, conservation, and management. The adaptability of Cicada-MET to various research questions, spatial scales, and long-term approaches, along with its quantitative accuracy and ease of use, make it a valuable resource for researchers and practitioners working with cicadas and their associated ecosystems

Long‑term response of open‑habitats species to wildfre salvage logging: the endangered European wild rabbit as example.

Salvage logging treatments, a type of logging to economic returns after natural disturbance, are often applied in the aftermath of wildfires. Specialist or dependent species of open-habitat usually increase their populations in the short-term after wild- fires and post-fire salvage logging. However, the long-term effects on threatened open-habitat species such as the European wild rabbit (Oryctolagus cuniculus L.) are still poorly known. Thus, plant productivity, habitat heterogeneity and rabbit abundance were studied in the north-east Iberian Peninsula in four type of post-fire treatment plots: (1) unburnt, (2) salvage logging with branches left on the ground, (3) salvage logging and manual removal of branches, and (4) recurrent fires. Both the time since the fire and the treatment affected plant productivity and habitat heterogeneity. Plant productivity was quicker in treatments when branches were left on the ground or when branches were removed than in recurrent fire plots. Rabbit relative abundance increased in the short term but dramatically declined over time after fires, especially in the plots where branches were left on the ground and with recurrent fires, in which rabbit abundances fell dramatically. In the long-term, the lack of food availability and adequate habitat structure are the main factors affecting the maintenance of the rabbit popula- tion. An appropriate moment for managing burnt areas to favour the persistence of rabbit is between the fifth and sixth year after the fire. These actions also benefit the reduction of environmental biomass and so help prevent future severe wildfires

Diversity, distribution and phenology of cicadas (Hemiptera: Cicadidae) in Catalonia (NE Iberian Peninsula)

Les cigales o cicàdids són insectes amb fase juvenil endogea, cicle vital llarg i cants audibles, importants a les xarxes tròfiques d’ecosistemes terrestres. Malgrat l’interès que han despertat arreu, la informació històrica a la península ibèrica, i en particular a Catalunya, és escassa. El catàleg d’hemípters de Martorell y Peña (1879) hi cita set espècies. Després d’aquesta data, les cigales van rebre molt poca atenció fins al segle XXI. La informació acumulada els darrers anys permet estudiar la diversitat, distribució i fenologia del grup. A tal efecte, es va realitzar una cerca bibliogràfica mitjançant cercadors acadèmics, i es van analitzar les dades del portal ornitho.cat pel període 2006-2020 (N=3468 registres). Es presenta el catàleg de cicàdids de Catalunya que conté 12 espècies, un nombre comparable al d’altres territoris europeus: les cigales grossa, del pi, de l’olivera i negra, respectivament Lyristes plebejus Scopoli, 1763, Cicada orni Linné, 1758, C. barbara Stal, 1866 (al·lòctona introduïda) i Cicadatra atra Olivier, 1790; les brunzidores ala-roja, sigil·lada, de garriga i cotonosa, respectivament Tibicina haematodes Scopoli, 1763, T. quadrisignata Hagen, 1855, T. garricola Boulard, 1983 i T. tomentosa Olivier, 1790; i les cigalelles europea occidental, vespera, culprima i argentada, respectivament Cicadetta petryi Schumacher, 1924, Hilaphura varipes Waltl, 1837, Euryphara dubia Rambur, 1840 i Tettigettalna argentata Olivier, 1790. Es mostren mapes de riquesa i distribució d’espècies en quadrícules UTM de 5 × 5 km, diagrames de distribució altitudinal i fenologia per les espècies més comunes, així com il·lustracions originals de suport a la identificació. Aquest treball il·lustra el potencial de la ciència ciutadana per ampliar el coneixement de grups d’insectes poc estudiats i estableix un escenari de referència sobre el que fonamentar futurs estudis de la distribució i ecologia dels cicàdids.True cicadas (Cicadidae) are insects with a juvenile phase spent belowground, a long life cycle and audible songs, that are important in the trophic networks of terrestrial ecosystems. Despite the interest they arouse, historical information in the Iberian Peninsula, and more specifically in Catalonia, is scarce. The catalogue of Hemipteran by Martorell y Peña (1879) cited seven species. After that date, cicadas received very little attention until the 21st century. The information accumulated in recent years allowed us to study the diversity, distribution and phenology of the group. To this end, a bibliographic search was carried out using the academic search engines, and the data hosted at ornitho.cat website was analysed for the period 2006-2020 (N= 3468 records). The catalogue of cicadas of Catalonia presented here contains 12 species, a number comparable to that of other European territories: Cicadinae Lyristes plebejus Scopoli, 1763, Cicada orni Linné, 1758, C. barbara Stal, 1866 (introduced non-native) and Cicadatra atra Olivier, 1790; Tibicininae Tibicina haematodes Scopoli, 1763, T. quadrisignata Hagen, 1855, T. garricola Boulard, 1983 and T. tomentosa Olivier, 1790; and Cicadettinae Cicadetta petryi Schumacher, 1924, Hilaphura varipes Waltl, 1837, Euryphara dubia Rambur, 1840 and Tettigettalna argentata Olivier, 1790. We provide species richness and distribution maps in 5 × 5 km UTM grids, altitudinal distribution and phenology diagrams for the most common species, as well as original illustrations to support identification. This work shows the potential of citizen science to expand the knowledge of a scarcely studied group of insects and establishes a baseline scenario on which to base future studies of the distribution and ecology of cicadas

Estudi dels patrons de colonització postincendi en vertebrats al llarg de gradients ambientals i espacials

Wildfires are natural perturbations that affect the structure of the landscape and biodiversity. In the Mediterranean basin, wildfires occur especially in hot seasons. However, in recent years the number of fires with the size of them has been increasing, associated with human intervention. In this thesis, I analyse how the gradient of regional aridity in Catalonia affects the recovery of vegetation, the richness of bird species and shrubland warbler abundance. The relative role of two hypotheses on the abundance of rodents in the first moments after a wildfire is evaluated. These opposite hypotheses make reference to the ability of rodents to resist the fire into refuges or, on the other hand, to colonize burnt areas from the unburnt area. Finally, I study how the postfire and the management of burnt wood can affect the recolonization of rodentsEls incendis forestals són alteracions naturals que afecten l'estructura del paisatge i la biodiversitat. A la conca mediterrània, els incendis forestals es donen especialment en les estacions caloroses. Tanmateix, en els darrers anys tant el nombre d’incendis con la mida dels mateixos ha anat en augment, associat amb la intervenció humana. En aquesta tesi s’analitza com el gradient d'aridesa regional de Catalunya afecta a la recuperació de la vegetació, la riquesa d'espècies d'aus i l’abundància de tallarols de matollar. S’avalua el paper relatiu de dues hipòtesis sobre l'abundància de rosegadors en els primers moments després d'un incendi forestal. Aquestes hipòtesis contraposades fan referència a la capacitat dels rosegadors a resistir el pas del foc en refugis o, per altre banda, a la colonitzar des de l'àrea no cremada. Finalment, s’avalua com la tala postincendi i la gestió de la fusta cremada poden afectar la recolonització de rosegador

Effects of Post-Fire Management on a Mediterranean Small Mammal Community

Wildfires simplify ecosystems, modifying the ecological niches of the fauna living in the recently burned areas. Small mammals respond rapidly to changes in habitat structure and composition after fire, but the effects of fire can be ameliorated by some management strategies (e.g., salvage logging). Hence, it is necessary to explore whether alternative management strategies may be able to return the ecosystem to its initial state. We studied the small mammal community by live trapping on eight plots under different post-fire treatments in Sant Llorenç del Munt i l’Obac Natural Park (Barcelona province, NE Spain). At the community level, an increase in overall relative abundance and species density was observed in the burned areas. Apodemus sylvaticus, the most abundant mammal in study area, used woody debris piles as a shelter against predators. Mus spretus was more abundant in post-fire sites with large open areas interspersed with woody debris piles. Crocidura russula steadily increased its presence in later successional stages when ground cover became more complex. Our results suggest that combining different management strategies may be appropriate to improve the habitat suitability and biodiversity of small mammals and other key open-land species throughout the burned area