Search

Lichens are one of the most responsive components of the ecosystem to reactive forms of nitrogen. In this work, we selected the lichen genera Cladonia and Usnea, composed of terricolous and epiphytic lichens respectively, and described as sensitive to nitrogen, to test the effects of different doses of nitrogen on lichen physiological parameters (photobiont and mycobiont vitality, chitin quantification, nitrogen content and stable isotopes analysis). The main objectives were to check if the activation of protective mechanisms could be stimulated in case of chronic stress (low nitrogen increase for prolonged time), and, if so, if a toxicity threshold could be identified above which these mechanisms fail. The two lichen genera were generally affected by prolonged exposure to increased nitrogen availability. However, Cladonia rangiformis was able to maintain physiological functioning at the lowest nitrogen doses used, whereas thalli of Usnea become overwhelmed. Moreover, the mycobiont appeared to be more sensitive than the photobiont responding to lower nitrogen doses. Although only studies of longer duration and testing more nitrogen doses will be able to determine an accurate toxicity threshold, these results give important clues on the use of lichens as biomonitors for the establishment of environmental policies.

Biodiversity is declining due to the impact of human activities. However, public awareness of the biodiversity crisis is low, particularly for plants, creating a barrier to engage with conservation programs. In this perspective, we show how citizen science and mobile apps can be used as educational tools to raise awareness about plant biodiversity among students and the general public. We examine the outcomes of three Bachelor of Science activities as well as two informal education initiatives. We discuss the potential of these approaches as educational and outreach tools. Our results show that citizen science and mobile apps are excellent tools for engaging society in biodiversity conservation and environmental issues.

A common view is that honeybees are mostly managed by beekeepers for commercial purposes or as a hobby, especially in Europe. This misconception is probably due to the lack of systematic studies on wild colonies of honeybees in Europe in comparison to other regions of the world. Since we are used to considering this species as “domesticated”, we may be induced to disregard activities not distinctly linked with colony survival, reproduction, or productivity. Washboarding is one of them in which the entire colony stops resource collection activities; numerous individual bees assemble on the front side of the hive and perform repetitive movements back and forth. They are curiously synchronised but apparently without a scope. In this exploratory work, we carried out a literature review of available, mostly grey, literature. Assuming this behaviour may be linked to cavity-nesting and to tree trunks or rocks being rough surfaces hosting various cryptogams, we performed preliminary observations and manipulative experiments. From our survey, we depict that washboarding is frequently reported in grey literature/beekeepers’ reports, but rarely mentioned in scientific literature. Beekeepers who responded to a designed questionnaire observed this behaviour in various ecological situations, with no trend emerging. Our preliminary experiment of placing cryptogams in front of managed hives resulted in honeybees removing lichens (foliose types) or covering with propolis, and all species were affected. Further research is needed to clarify if lichens are removed because of their chemical compounds, because of hosting potentially toxic microorganisms, or collected as resources.

Context: Acacia longifolia is a native legume of south-eastern Australia and Tasmania and is invasive in many parts of the world. A key feature to its success is the production of a high quantity of flowers every season, resulting in a massive seedbank that remains dormant in the soil for decades. Many studies have been performed on this species’ reproductive biology, but none has focused on flowering in detail. Aims: Our main objective was to understand this species’ resource allocation strategy that ensures its successful reproduction in the invasive range. Methods: We developed an integrative approach, assessing flowering at different levels, namely, canopy and branch flowering (macro scale), downscaling to individual flower functional stages and their duration, pollen longevity and stigma receptivity (micro scale). We performed this study in three different locations in sand dunes along the Portuguese coast with different environmental conditions. Key results: Canopy flowering shows no difference among sites. Pollen and stigma assessment showed that this species is protogynous, with the stigma being highly receptive long before pollen is released. Once released, pollen lasts roughly 72 h. Individual flowers are relatively short-lived, with a rapid progression from closed flower buds to fully open flowers. Implications: Our results indicated that A. longifolia has a resource trade-off strategy of investing in flowers and pollen that are relatively short-lived, which are counterbalanced by their massive quantities.

Eucalyptus globulus Labill. is one of the most widely planted hardwood species worldwide. This species occupies a quarter of the country's forested area in Portugal, so there is a growing concern about its post-fire dispersal. Although it is generally recognised that fire promotes E. globulus natural regeneration and that precipitation and topography influence recruitment, little is known about the role of post-fire conditions on the establishment of the species following off-season fires. We examine how post-fire conditions affect E. globulus natural regeneration and invasive potential. Sapling establishment was assessed in plantations and under old and large isolated eucalyptus trees (seed-trees) following two off-season fire events (2017 June and October fires). Abiotic and biotic local factors affected differently sapling establishment in plantations and under seed-trees. In plantations, sapling cover was more influenced by tree-related traits (age and height), whereas the conditions beneath seed-trees mitigated the impact of harsh conditions on saplings. In both cases, post-fire climatic conditions constrained natural regeneration, with less impact under seed-trees, reinforcing their importance in establishment success. Thus, isolated seed-trees should be considered while managing the species’ unplanned spread.

As climate change increasingly affects forest ecosystems, detailed understanding of major effects is important to anticipate their consequences under future climate scenarios. The Mediterranean region is a prominent climate change hotspot, and evergreen cork oak (Quercus suber L.) woodlands are particularly climatically sensitive due to cork (bark) harvesting. Cork oak’s drought avoidance strategy is well-known and includes structural and physiological adaptations that maximise soil water uptake and transport and limit water use, potentially leading to reduced stem and cork growth. Trees’ responses to cope with water-limited conditions have been extensively described based on cork-rings width and, more recently, on cork-rings density, in dendroecological studies. However, so far, tree functional attributes and physiological strategies, namely photosynthetic metabolism adjustments affecting cork formation, have never been addressed and/or integrated on these previous cork-rings-based studies. In this study, we address the relation between carbon and oxygen stable isotopes of cork rings and precipitation and temperature, in two distinct locations of southwestern Portugal–the (wetter) Tagus basin peneplain and the (drier) Grândola mountains. We aimed at assessing whether the two climatic factors affect cork-ring isotopic composition under contrasting conditions of water availability, and, therefore, if carbon and oxygen signatures in cork can reflect tree functional (physiological and structural) responses to stressful conditions, which might be aggravated by climate change. Our results indicate differences between the study areas. At the drier site, the stronger statistically significant negative cork δ13C correlations were found with mean temperature, whereas strong positive cork δ18O correlations were fewer and found only with precipitation. Moreover, at the wetter site, cork rings are enriched in 18O and depleted in 13C, indicating, respectively, shallow groundwater as the water source for physiological processes related with biosynthesis of non-photosynthetic secondary tissues, such as suberin, and a weak stomatal regulation under high water availability, consistent with non-existent water availability constrains. In contrast, at the drier site, trees use water from deeper ground layers, depleted in 18O, and strongly regulate stomatal conductance under water stress, thus reducing photosynthetic carbon uptake and probably relying on stored carbon reserves for cork ring formation. These results suggest that although stable isotopes signatures in cork rings are not proxies for net growth, they may be (fairly) robust indicators of trees’ physiological and structural adjustments to climate and environmental changes in Mediterranean environments.

The pinewood nematode (PWN), Bursaphelenchus xylophilus, responsible for the pine wilt disease (PWD), is a major threat to pine forests worldwide. Since forest mortality due to PWN might be exacerbated by climate, the concerns regarding PWD in the Mediterranean region are further emphasized by the projected scenarios of more drought events and higher temperatures. In this context, it is essential to better understand the pine species vulnerability to PWN under these conditions. To achieve that, physiological responses and wilting symptoms were monitored in artificially inoculated Pinus pinaster (P. pinaster), Pinus pinea (P. pinea), and Pinus radiata (P. radiata) saplings under controlled temperature (25/30°C) and water availability (watered/water stressed). The results obtained showed that the impact of PWN is species-dependent, being infected P. pinaster and P. radiata more prone to physiological and morphological damage than P. pinea. For the more susceptible species (P. pinaster and P. radiata), the presence of the nematode was the main driver of photosynthetic responses, regardless of their temperature or water regime conditions. Nevertheless, water potential was revealed to be highly affected by the synergy of PWN and the studied abiotic conditions, with higher temperatures (P. pinaster) or water limitation (P. radiata) increasing the impact of nematodes on trees’ water status. Furthermore, water limitation had an influence on nematodes density and its allocation on trees’ structures, with P. pinaster revealing the highest nematode abundance and inner dispersion. In inoculated P. pinea individuals, nematodes’ population decreased significantly, emphasizing this species resistance to PWN. Our findings revealed a synergistic impact of PWN infection and stressful environmental conditions, particularly on the water status of P. pinaster and P. radiata, triggering disease symptoms and mortality of these species. Our results suggest that predicted drought conditions might facilitate proliferation and exacerbate the impact of PWN on these two species, through xylem cavitation, leading to strong changes in pine forests of the Mediterranean regions.

Increasing interest in Corema album L. is raising due to the appealing white colour and potential health benefits related to its bioactive composition. White fruits production culminates in late August on coastal dunes, but fruits of various colours are present almost till flowering (late February). We undertook a preliminary physical-chemical characterisation (biometric, CIELab colour, pH, soluble solids content and titrable acidity) of a late fruit collection to disentangle maturity progression and to reveal latent qualities for future utilisation. Irrespective of fruit perceived colouration (white, translucent, brown, brown with black spots and black), the characterized high acidity (1-3 g.100 mL-1) is suggestive that over-mature fruits can still be further explored as food additives. Moreover, using a multivariate exploratory technique, we found a clear fruit’s maturation progression from white/translucent to black, a so-far unreported maturity stage. Addressing gaps in plant phenology and fruit’s maturity behaviour is needed before undertaking cultivation.

The aim of this report is to illustrate by means of a series of case studies the implementation of mapping and assessment of forest ecosystem services in different contexts and geographical levels. Methodological aspects, data issues, approaches, limitations, gaps and further steps for improvement are analysed for providing good practices and decision making guidance. The EU initiative on Mapping and Assessment of Ecosystems and their Services (MAES), with the support of all Member States, contributes to improve the knowledge on ecosytem services. MAES is one of the building-block initiatives supporting the EU Biodiversity Strategy to 2000.

Acacia spp. are among the most widespread and prominent invaders within Mediterranean-type ecosystems, where have already shown the capability to deeply change the characters and the functioning of invaded ecosystems (like in Portugal or S Africa: e.g. Holmes & Cowling, 1997; Hellmann et al., 2011). In Sicily, just in the last few years, two Australian Acacias, notably Acacia cylops A. Cunn. ex G. Don and A. saligna (Labill.) H.L.Wendl., started to regenerate abundantly within different areas (especially afforested sites). However their naturalization process has not been studied up to now.