Myrica Faya Research Articles

The combined effect of diffuse radiation and leaf wetness on functional traits and transpiration efficiency on a cloud forest species.

Cloud forests are unique biomes that thrive in foggy environments for a substantial part of the season. Fog in cloud forests plays two critical roles: it reduces incoming radiation and creates a humid environment, leading to the wetting of the canopy. This paper aims to investigate the combined effect of both radiation and wetness on Myrica faya Wilbur-a cloud forest species present in subtropical regions-both directly in plants and through simulations. Experiments consisted of a controlled environment with two levels of radiation and leaf wetness: low radiation/wet conditions, and high radiation/no-wetness; and three treatments: continuous low radiation and wetness, continuous high radiation and no wetness and alternate high low radiation and alternate wetness. The results revealed that a combination of low radiation and leaf wetness significantly improves leaf stomata conductance and increases the specific leaf area (SLA). Changes in SLA were driven by leaf size changes. However, the minimum leaf conductance (gmin) did not respond to any of the treatments. The simulations focused on exploring the impact of radiation and canopy wetness on transpiration efficiency (TE), i.e. the ratio between photosynthesis (An) and transpiration (Tc). The simulations demonstrated that TE increased exponentially as the canopy was gradually wetted, regardless of the radiation environment. This increase in TE results from Tc approaching zero while An maintains positive values. Overall, this study provides an integrated understanding of how fog alters M. faya functioning and, potentially, other cloud forest tree species.

Allometric relationships for eight species of 4-5 year old nitrogen-fixing and non-fixing trees.

Allometric equations are often used to estimate plant biomass allocation to different tissue types from easier-to-measure quantities. Biomass allocation, and thus allometric equations, often differs by species and sometimes varies with nutrient availability. We measured biomass components for five nitrogen-fixing tree species (Robinia pseudoacacia, Gliricidia sepium, Casuarina equisetifolia, Acacia koa, Morella faya) and three non-fixing tree species (Betula nigra, Psidium cattleianum, Dodonaea viscosa) grown in field sites in New York and Hawaii for 4-5 years and subjected to four fertilization treatments. We measured total aboveground, foliar, main stem, secondary stem, and twig biomass in all species, and belowground biomass in Robinia pseudoacacia and Betula nigra, along with basal diameter, height, and canopy dimensions. The individuals spanned a wide size range (<1-16 cm basal diameter; 0.24-8.8 m height). For each biomass component, aboveground biomass, belowground biomass, and total biomass, we determined the following four allometric equations: the most parsimonious (lowest AIC) overall, the most parsimonious without a fertilization effect, the most parsimonious without canopy dimensions, and an equation with basal diameter only. For some species, the most parsimonious overall equation included fertilization effects, but fertilization effects were inconsistent across fertilization treatments. We therefore concluded that fertilization does not clearly affect allometric relationships in these species, size classes, and growth conditions. Our best-fit allometric equations without fertilization effects had the following R2 values: 0.91-0.99 for aboveground biomass (the range is across species), 0.95 for belowground biomass, 0.80-0.96 for foliar biomass, 0.94-0.99 for main stem biomass, 0.77-0.98 for secondary stem biomass, and 0.88-0.99 for twig biomass. Our equations can be used to estimate overall biomass and biomass of tissue components for these size classes in these species, and our results indicate that soil fertility does not need to be considered when using allometric relationships for these size classes in these species.

Tree symbioses sustain nitrogen fixation despite excess nitrogen supply

AbstractSymbiotic nitrogen fixation (SNF) is a key ecological process whose impact depends on the strategy of SNF regulation—the degree to which rates of SNF change in response to limitation by N versus other resources. SNF that is obligate or exhibits incomplete downregulation can result in excess N fixation, whereas a facultative SNF strategy does not. We hypothesized that tree‐based SNF strategies differed by latitude (tropical vs. temperate) and symbiotic type (actinorhizal vs. rhizobial). Specifically, we expected tropical rhizobial symbioses to display strongly facultative SNF as an explanation of their success in low‐latitude forests. In this study we used 15N isotope dilution field experiments in New York, Oregon, and Hawaii to determine SNF strategies in six N‐fixing tree symbioses. Nitrogen fertilization with +10 and +15 g N m−2 year−1 for 4–5 years alleviated N limitation in all taxa, paving the way to determine SNF strategies. Contrary to our hypothesis, all six of the symbioses we studied sustained SNF even at high N. Robinia pseudoacacia (temperate rhizobial) fixed 91% of its N (%Ndfa) in controls, compared to 64% and 59% in the +10 and +15 g N m−2 year−1 treatments. For Alnus rubra (temperate actinorhizal), %Ndfa was 95%, 70%, and 60%. For the tropical species, %Ndfa was 86%, 80%, and 82% for Gliricidia sepium (rhizobial); 79%, 69%, and 67% for Casuarina equisetifolia (actinorhizal); 91%, 42%, and 67% for Acacia koa (rhizobial); and 60%, 51%, and 19% for Morella faya (actinorhizal). Fertilization with phosphorus did not stimulate tree growth or SNF. These results suggest that the latitudinal abundance distribution of N‐fixing trees is not caused by a shift in SNF strategy. They also help explain the excess N in many forests where N fixers are common.

Land-use change and windstorms legacies drove the recolonization dynamics of laurel forests in Tenerife, Canary islands

Laurel forests are quite relevant for biodiversity conservation and are among the island ecosystems most severely damaged by human activities. In the past, Canary laurel forests have been greatly altered by logging, livestock and agriculture. The remains of laurel forests are currently protected in the Canary Islands (Spain). However, we miss basic information needed for their restoration and adaptive management, such as tree longevity, growth potential and responsiveness to natural and anthropogenic disturbances. Using dendrochronological methods, we studied how forest dynamic is related to land-use change and windstorms in two well-preserved laurel forests on Tenerife Island. Wood cores were collected from over 80 trees per stand at three stands per forest. We used ring-width series to estimate tree ages and calculate annual basal area increments (BAI), cumulative diameter increases, and changes indicative of released and suppressed growth. Twelve tree species were found in all stands, with Laurus novocanariensis, Ilex canariensis and Morella faya being the most common species. Although some individuals were over 100 years old, 61.8%–88.9% of the trees per stand established between 1940 and 1970, coinciding with a post-war period of land abandonment, rural exodus and the onset of a tourism economy. Some trees have shown growth rates larger than 1 ​cm diameter per year and most species have had increasing BAI trends over the past decades. Strong growth releases occurred after windstorms at both sites, but the effects of windstorms were site-dependent, with the 1958 storm affecting mainly the eastern tip of the island (Anaga massif) and the 1991 storm the western tip (Teno massif). Given the great ability of laurel forest trees to establish after land use cessation and to increase growth after local disturbances such as windstorms, passive restoration may be sufficient to regenerate this habitat in currently degraded areas.

Together Apart: Evaluating Lichen-Phorophyte Specificity in the Canarian Laurel Forest.

The effects of host tree identity on epiphyte lichen communities are a controversial issue, as the results obtained in different forest environments studied are not consistent. We investigated the host preferences for lichens in the laurel forest of Macaronesia. For this purpose, we analyzed the lichen communities growing on the four most common trees (Erica canariensis Rivas-Mart., M. Osorio and Wildpret, Morella faya (Aiton) Wilbur, Laurus novoca-nariensis Rivas-Mart., Lousa, Fern. Prieto, E. Días, J.C. Costa and C. Aguiar, and Ilex canariensis Poir. in Lamarck) in the laurel forest of the Canary Islands. The diversity, richness, and lichen composition showed a repetitive and common pattern with the functional traits studied. Although the existence of specificity with respect to the phorophyte species was not demonstrated, there was a clear affinity of the epiphytic lichens to the physico-chemical features of the bark (texture and pH), canopy architecture, foliar characteristics, etc. Our results highlight the importance of the natural diversity of tree species in the laurel forest. Due to the diversity and uniqueness of the lichen species that support each of the phorophytes, this fact should be taken into account in landscape protection and restoration actions, especially in those islands where the forest is highly fragmented.

Rhizobial root nodules in aeolian sandstones on Madeira (Piedade Beds, Pleistocene) and their significance for palaeonvironmental and “originator” hypotheses

Numerous rhizoliths were observed in aeolian Pleistocene sediments (ca. 80 ka) on the Ponta da São Lourenço Peninsula on eastern Madeira. Surface of some rhizoliths locally exhibit bulbous swellings which were identified as rhizobial root nodules. Based on palaeoenvironmental analysis and a comparison with other rhizoliths in the Macaronesian region, the arborescent species of Morella faya, domestic to the Madeira Island, is suggested as the source taxon for the rhizoliths. Actinorhizal fungi of the genus Frankia are considered to be responsible for creating the nodules. Tree rhizoliths also document the changes in climate and plant cover composition on Madeira. Their origin dates to a rather humid period dominated by partly continuous arborescent vegetation.

Fog mitigates the consequences of a profligate water use strategy in a Macaronesian cloud forest tree species

How plants thrive in a cloud immersed environment where leaves are intermittently wet and the environmental conditions that drive transpiration and growth are limited, raises a relevant question in fog affected ecosystems. In order to provide insight into how cloud immersion and fog interception may affect Macaronesian laurisilva forests, micrometeorological variables, artificial fog water collection, throughfall, soil water content and the altitude of the trade wind inversion layer, together with the hourly sap flow, Qt, of a dominant tree species, Myrica faya, were measured at an exposed site of the Anaga Massif Rural Park Biosphere Reserve (Tenerife, Canary Islands) over a period of one year. Foggy conditions led to a 45.1% reduction in global radiation and a more than a 10-fold decrease in sap flow, throughout all day hours. M. faya showed a weak control of the transpiration rate and a profligate water use strategy, such that a substantial night-time sap flow, Qtn, was observed under high nocturnal atmospheric evaporative demand, representing 23.3% of the total daily Qt, even though fog was more frequent at night. Fog water interception resulted in canopy wetting and dripping for at least 55.0% of the time, and an associated downward xylematic sap transport in the most apical branches, i.e. in foliar water uptake. This represented 4.0% of the upward sap flow and was observed in 26.7% of the hourly Qt records. Nocturnal transpiration was also enhanced by the entry of previous foliar moisture. This general plant and climatic phenomenology was related at the mesoscale with the trade wind inversion height in the subtropical Macaronesia area.

Breeding of the endemic Azores Woodpigeon Columba palumbus azorica: a two-year study on Pico Island

ABSTRACT Capsule The Azores Woodpigeon Columba palumbus azorica nested in low altitude forests dominated by native Morella faya, and had an extended breeding season, with high failure rates, particularly during incubation. Aims This work aimed to study the breeding phenology, nesting habitat, clutch size and nesting success of the Azores Woodpigeon. Methods Areas for nest searching were defined randomly. A total of 125 nests were monitored during two breeding seasons on Pico Island, Azores. Survival rates were calculated according to Mayfield method. Results Although most nests were found in forests dominated by introduced Pittosporum undulatum, our study highlights a strong selection for those dominated by native Morella faya. The Azores Woodpigeon seemed to avoid native Laurel forest for nesting. There was a preference for nesting in small or medium trees. Nests heights ranged between 3 and 14 m, with a mean (± se) of 7.0 ± 0.2 m. Egg laying occurred from late-February to early-August (in 2016) or to early-September (in 2017). Clutch size did not vary with time; its mean value was 1.72 ± 0.05 eggs (range: 1–2 eggs). The probability of breeding success was estimated at 0.204 ± 0.113 in 2016 and 0.152 ± 0.103 in 2017. In both years, breeding failure mostly occurred during incubation. Survival differed between the two main nesting habitats, being higher in forests dominated by Morella faya. Conclusions The Azores Woodpigeon does not seem to rely on native Laurel forest for nesting, which confirms previous results. Its preference and higher survival in another strongly threatened habitat is cause for concern. The probability of breeding success was higher than previously reported but still low. Illegal hunting of adult birds, because of alleged damages to crops, might partially explain the high proportion of eggs that did not hatch.

Oceanic Island forests buried by Holocene (Meghalayan) explosive eruptions: palaeobiodiversity in pre-anthropic volcanic charcoal from Faial Island (Azores, Portugal) and its palaeoecological implications

In Faial Island (Azores Archipelago, North Atlantic Ocean), charcoalified and mummified wood fossils have been reported within late Holocene (Meghalayan) pyroclastic deposits from the Caldeira Formation. Due to their recent age, a detailed study conveys a snapshot into Azorean palaeophytodiversity and palaeovegetation, ca. 7–5 centuries before the arrival of Portuguese settlers to the Azores Islands. Here we provide the first detailed anatomical and taxonomical study of these wood fossils. In total, 41 samples were collected from seven localities, mainly from a ~1200 yr BP ignimbrite. Field work revealed autochthonous and paraautochthonous assemblages, with tree trunks in upright position. The anatomical study of the fossil woods resulted in the identification of Juniperus brevifolia, Laurus azorica, Myrsine retusa, Morella faya, Picconia azorica, Prunus lusitanica subsp. azorica, and Vaccinium cylindraceum. Two fossil assemblages are comparable to the proposed potential natural vegetation (PNV) for the Azores. Surprisingly, P. lusitanica subsp. azorica was the second most abundant fossil wood suggesting that this tree was more abundant in a recent past in Faial Island and probably in the archipelago. This is corroborated by historical accounts, and its modern scarcity was certainly anthropically driven. Identifying Holocene plant macrofossils is essential to properly reconstruct oceanic islands terrestrial palaeoecosystems, especially where forests with high percentage of entomophilous taxa are underrepresented in palaeopalynological limnic record. Further work is necessary to reconstruct Faial Island and Azores archipelago palaeovegetation which is essential to provide an ecosystem base-line for restoration and management.

The impact of climate change on water fluxes in a Macaronesian cloud forest

AbstractFog phenomena and their associated meteorological variables were continuously monitored during 4 years in an evergreen laurisilva cloud forest of the Anaga Massif Biosphere Reserve (Tenerife, Canary Islands), in order to establish its current dynamics. Fog was more frequent during night through early morning and in the afternoon, and particularly from May until September, coincidental with a frequent immersion of the 1025 m a.s.l. experimental site in the cloud layer of wind‐driven stratocumulus. The concomitant meteorological conditions during different fog regimes, characterized according to visibility (Ω) ranges, were compared with those when fog was absent. The presence of fog was associated with a significant reduction in global solar radiation, Rg, increased wind speed, and lower and more stable ambient temperatures. The foggy versus fog‐free hourly medians of Rg were found to be linearly related, whereas the proportion of median Rg reduction due to fog varied logarithmically with Ω. However, foggy versus fog‐free extreme values of the hourly Rg distributions departed from such a linear trend. By contrast, hourly temperatures during foggy versus fog‐free periods behaved linearly for most of the Ω range, except for very dense fog, Ω ≤ 100 m. Transpiration of the canopy, intermittently wetted due to interception of both rain and fog water droplets, was determined by quantifying the water balance at leaf scale with a mathematical model for the two representative hypostomatous species present at the site: the arboreal shrub Erica platycodon, with needle‐like leaves, and the laurophyll tree Myrica faya. Both tree transpiration and evaporation of the intercepted fog water were predictively higher during summer. By contrast, transpiration was reduced during February, in agreement with a 1 year period of sap velocity measurements, and was not appreciably affected by soil moisture content. The consequences of an anticipated downward shift of the stratocumulus cloud layer and of various projected Representative Concentration Pathways (RCPs) scenarios in the Macaronesian area were simulated, yielding in all cases a significant rise in transpiration for both species. Particularly, the simulated RCPs scenarios implied 29%–73% increments in transpiration from the actual values. Because fog is concomitant with lower temperatures and vapour pressure deficit, the modification of its current distribution as a consequence of climate change may have a direct effect on such associated meteorological variables, and therefore a meaningful impact in the water relations of the laurel cloud forests.

Ethnobotanical Knowledge in Sete Cidades, Azores Archipelago: First Ethnomedicinal Report.

Knowledge about folk medicines is limited to elder community members of remote communities, like Sete Cidades in the Azores. The Azores, 1300 km west of Portugal, are nine volcanic islands, totalling 2330 km2 of land dispersed by 173,200 km2 in the North Atlantic Ocean. The present study aims to scientifically document the uses of plant species for medicinal purposes, in the Sete Cidades. Twenty-eight community members from 40 to 84 years of age, of whom half were 55 to 64 years old, were interviewed. Twenty-nine taxa were reported as being used for medicinal purposes, ten of which have not been previously reported for ethnomedicinal use in Portugal, with a first record of the use of Morella faya. Leaves were the most used plant part (55%), and decoction the most common preparation mode. The five reported taxa with both the highest use value (0.71–0.25) and relative frequency of citation (0.14–0.11) were Clinopodium menthifolium subsp. ascendens, Aloysia citriodora, Mentha x piperita, Citrus limon and Rosmarinus officinalis. The traditional uses of some of the reported plants are supported by scientific studies, confirming their ethnomedicinal value and the need to preserve local knowledge of folk medicine practices.

Tests of Hexazinone and Tebuthiuron for Control of Exotic Plants in Kauai, Hawaii

Non-native plant species have become serious pests in Hawaii’s delicate island ecosystems. It is necessary to control invasive plants. The herbicides hexazinone and tebuthiuron were evaluated for defoliation efficacy to control several major invasive plants and for non-target effects on native plants at Site I in a rainforest at 1200 m elevation and Site II in a mesic area at 640 m elevation on the island of Kauai, Hawaii. The invasive weed species in the sites included daisy fleabane (Erigeron karvinskianus DC.), faya tree (Myrica faya Ait.), strawberry guava (Psidium cattleyanum Sabine), banana passion fruit (Passiflora mollissima Bailey), vaseygrass (Paspalum urvillei Steud.), and highbush blackberry (Rubus argutus Link. 1822). Native plants included ohia lehua (Metrosideros polymorpha Gaudich.), naupaka (Scaevola cerasifolia Labill.), pilo (Hedyotis mannii), hona (Urera glabra (Hook. &amp; Arn.)), aalii (Dodonaea viscosa Jacq.), and amau (Sadleria sp.). The results showed that broadcast applications of hexazinone granules and tebuthiuron pellets were effective on some of those invasive species. Herbicidal tolerance varied among the native species. For example, D. viscosa showed high tolerance to hexazinone. S. cerasifolia was susceptible to hexazinone, but not to tebuthiuron. The inconsistent defoliation of Sadleria sp. occurred among different applications rates of the two herbicides. M. polymorpha, particularly when it was small, could tolerate hexazinone and tebuthiuron. U. glabra was severely injured by the two herbicides. H. mannii was moderately tolerant to hexazinone, but fairly sensitive to tebuthiuron. The invasive loblolly pine (Pinus taeda L.) was highly tolerant to hexazinone, but was very sensitive to tebuthiuron. M. faya was very sensitive to hexazinone, but very tolerant to tebuthiuron. P. cattleyanum was sensitive to both herbicides. Six and nine months after hexazinone and tebuthiuron treatment, respectively, native plants were transplanted into the Sites to observe injury from residual herbicides. Approximately less than 10% mortality was observed for the out-planted native species three months after planting (MAP), indicating that the native species showed less injury in the early period of transplant. The mortality of the three endangered species Kauai hau kuahiwi (Hibiscadelphis distans), Kauai delissea (Delissea rhytidosperma H.Mann) and kawawaenohu (Alsinidendron lynchnoides), however, increased as the MAP increased. Overall, broadcast treatments of hexazinone and tebuthiuron at rates higher than 1 kg active ingredient per hectare would be problematic. The dissipation half-life values of hexazinone and tebuthiuron in the 1-15 cm layer of soils at the two sites were approximately 7 days and greater than 180 days, respectively.

Identifying potential distributions of 10 invasive alien trees: implications for conservation management of protected areas.

Tree invasion has the potential to negatively affect biodiversity and ecosystems, with invasive alien trees (IATs) expanding widely in protected areas (PAs) across different habitats. Thus, the effectiveness of PAs might be reduced. Investigation of the distributions of IAT is urgently required to improve the effective conservation management of PAs. We projected the potential distributions of 10 IATs, which included Acacia mearnsii, Ardisia elliptica, Cecropia peltata, Cinchona pubescens, Leucaena leucocephala, Melaleuca quinquenervia, Miconia calvescens, Morella faya, Prosopis glandulosa, and Spathodea campanulata, that have a serious influence on global biodiversity and assessed the distribution possibilities of these IATs in PAs based on the PA categories of the International Union for Conservation of Nature (IUCN). The overall potential distributions of these 10 IATs included Latin America, central and southern Africa, southeastern Asia, eastern Australia and New Zealand, and western Europe. Annual mean temperature, temperature seasonality, annual precipitation, and soil bulk density were found to be important environmental variables for the potential distributions of these IATs. Overall, A. mearnsii, A. elliptica, C. peltata, L. leucocephala, M. quinquenervia, M. calvescens, and S. campanulata were distributed mainly in the IUCN PA categories of national parks and PAs with sustainable use of natural resources. We proposed the following for conservation management of PAs: (1) completion of species inventories for PAs, (2) better understanding of factors driving invasions in PAs, (3) assessment of the efficiency of management within particular PAs, and (4) evaluation of changes in trends regarding plant invasions in PAs under climate change conditions.

Polyphenols of Myrica faya inhibit key enzymes linked to type II diabetes and obesity and formation of advanced glycation end-products (in vitro): Potential role in the prevention of diabetic complications

Myrica faya Aiton (fire tree, faya) is an underused species with a diverse flavonoid composition (anthocyanins, flavonols, ellagitannins) which can promote positive effects on human health. M. faya has been reported to possess high antioxidant activities, but its potential in the prevention of type II diabetes has not been evaluated so far. In the present study, eight M. faya samples from different areas of Madeira and Azores archipelagos (Portugal) were collected to determine their phytochemical profile and then tested for their in vitro anti-diabetic and antioxidant activities. The analyzed extracts showed strong inhibitory activities towards α -glucosidase, aldose reductase and glycation of bovine serum albumin (BSA) and moderate effects towards α-amylase and lipase (by comparison with reference compounds). Cyanidin-3-O-glucoside and ellagitannins were the main bioactive agents involved in the anti-diabetic effects of M. faya. Such results may provide important scientific evidence for further utilization of M. faya as dietary or nutraceutical products for the prevention and/or control of hyperglycaemia-associated complications.

Species Distribution Modeling: Comparison of Fixed and Mixed Effects Models Using INLA

Invasive alien species are among the most important, least controlled, and least reversible of human impacts on the world’s ecosystems, with negative consequences affecting biodiversity and socioeconomic systems. Species distribution models have become a fundamental tool in assessing the potential spread of invasive species in face of their native counterparts. In this study we compared two different modeling techniques: (i) fixed effects models accounting for the effect of ecogeographical variables (EGVs); and (ii) mixed effects models including also a Gaussian random field (GRF) to model spatial correlation (Matérn covariance function). To estimate the potential distribution of Pittosporum undulatum and Morella faya (respectively, invasive and native trees), we used geo-referenced data of their distribution in Pico and São Miguel islands (Azores) and topographic, climatic and land use EGVs. Fixed effects models run with maximum likelihood or the INLA (Integrated Nested Laplace Approximation) approach provided very similar results, even when reducing the size of the presences data set. The addition of the GRF increased model adjustment (lower Deviance Information Criterion), particularly for the less abundant tree, M. faya. However, the random field parameters were clearly affected by sample size and species distribution pattern. A high degree of spatial autocorrelation was found and should be taken into account when modeling species distribution.

Ecosystem vs. community recovery 25 years after grass invasions and fire in a subtropical woodland

Summary Despite a large body of research documenting invasive plant impacts, few studies have followed individual invaded sites over decades to observe how they change, and none have contrasted how compositional impacts from invasion compare to ecosystem‐process impacts over a multi‐decadal time‐scale. Using direct measurements of plant density and composition and of ecosystems processes, we evaluate how ecosystem structure, above‐ground net primary production (ANPP), and above‐ground and soil nutrient pools compare over 25 years since fire and C4 grass invasions disrupted seasonally dry Hawaiian woodlands. We compare structure and function between primary woodland that has never burned and is largely native species‐dominated, with sites that had been the same woodland type but burned in alien‐grass‐fuelled fires in the 1970s and 1980s. The sites have not experienced fires since 1987. We report here that woody plant composition and structure continue to be dramatically changed by the initial invasions and fires that occurred 25 years ago and invaders continue to dominate in burned sites. This is reflected in continued low plant carbon pools in burned compared to unburned sites. Yet ANPP and N storage, which were dramatically lower in the initial decade after invasive‐grass fuelled fires, have increased and are now indistinguishable from values measured in intact woodlands. Soil carbon pools were resilient to both invasion and fire initially and over time. Above‐ground net primary production has recovered because of invasion of burned sites by a non‐native N‐fixing tree rather than because of recovery of native species. This invasive N‐fixing tree is unlikely to return C storage of the invaded sites to those of unburned woodland because of its tissue and growth characteristics and its interactions with invasive grasses. It does not facilitate native species but rather promotes a persistent invasive grass/N‐fixer savanna. Synthesis. We conclude that fire, an unusual disturbance in this system, has perpetuated the dominance of these sites by invasive species and that despite the dramatic recovery of above‐ground net primary production and N pools, the ecosystem continues to be in a distinctly different state than the pre‐fire, pre‐Melinis community. Thus, despite the absence of further disturbance (fire), there is no evidence that succession towards the original ecosystem is occurring. The fact that N pools and above‐ground net primary production recover because of a new invader (Morella faya), highlights the unpredictability of ecosystem trajectories in the face of altered regional species pools.

The influence of soil resources and plant traits on invasion and restoration in a subtropical woodland

It has been shown in some cases that nitrogen (N) addition to soil will increase abundance of plant invaders because many invaders have traits that promote rapid growth in response to high resource supply. Similarly, it has been suggested, and sometimes shown, that decreasing soil N via carbon (C) additions can facilitate native species recovery. Yet all species are unlikely to respond to resource supply in the same way. We asked how soil nutrients and competition affect native and exotic woody species in a restoration experiment where we added N or C, and crossed soil manipulation with the manipulation of dominant exotic grass abundance in a Hawaiian subtropical woodland. We related changes in survival and growth of outplanted individuals to native/exotic status and plant traits. As a group, N-fixers showed reduced survival compared to non-fixers in response to added N, with Morella faya (exotic) and Acacia koa (native) having dramatic negative responses. Among non-fixers, species with greater foliar %N had more positive survival responses to increasing soil N. Specific leaf area was not predictive of responses to nutrients or competition. In general, responses to carbon addition were weak, although reducing competition from existing exotic grasses was beneficial for all outplanted species, with N-fixers showing the most positive response. We conclude that commonly used restoration strategies to clear exotic species or lower soil resources with C addition will most greatly benefit N-fixing species, which themselves may be unwanted invaders. Thus statements about the influence of increased soil N on invasions should be carefully dissected by considering the traits (such as N-fixation status) of the regional species pool.

Consumption, growth and survival of the endemic stream shredder Limnephilus atlanticus (Trichoptera, Limnephilidae) fed with distinct leaf species

Oceanic freshwater communities tend to be species poor but rich in endemism due to their physical isolation. The ecology of endemic freshwater species is, however, poorly known. This study assessed allometric relationships, feeding preferences, growth and survival of larvae of the endemic stream insect Limnephilus atlanticus (Trichoptera, Limnephilidae) exposed to four leaf species differing in their physical and chemical characteristics ( Ilex perado , Morella faya , Alnus glutinosa and Clethra arborea ), in laboratory trials. All regression models used to estimate L. atlanticus dry mass from body and case dimensions and wet mass were significant, but wet mass and body length were the best predictors. Limnephilus atlanticus consumed all the four leaf species offered, but when given a choice, shredders significantly preferred A. glutinosa over the other three leaf species. Relative larval growth rate was significantly higher when L. atlanticus fed on A. glutinosa and I. perado leaves in comparison with the other leaf species. Survival of 95% was found when individuals fed on A. glutinosa leaves while it decreased to 75% when they fed on the other leaf species. Our results suggest that L. atlanticus can be an active shredder and that it exhibits the same basic patterns of food exploitation as its continental counterparts. The lack of an effect of shredders on litter decomposition in Azorean streams revealed by previous studies may thus be due to low densities or to a preference for food resources other than the low quality native litter species.

Evaluation of the inorganic content of six underused wild berries from Portugal: Potential new sources of essential minerals

The mineral content and levels of trace elements in six wild underused berries (Elaeagnus umbellata, Myrica faya, Rubus grandifolius, Sambucus lanceolata, Vaccinium padifolium and Vaccinium cylindraceum) have been determined by inductively coupled plasma-mass spectrometry after microwave digestion. The inorganic content of these foodstuffs has not been previously described in scientific literature (except for E. umbellata). Hence, this information is of high interest concerning the introduction of these non-commercial berries in the mainstream market. The analytical method has been validated analyzing a certified reference material and performing recovery experiments. The results obtained have been discussed using the Recommended Daily Allowance for minerals provided by the Commission of the European Community, and a comparison between the composition of the analyzed berries and different commercialised berries has been carried out. Data obtained in this study support the consumption of these less-known berries, in particular R. grandifolius and S. lanceolata, as potential novel sources of essential minerals.

Treatments for seed germination improvement in Prunus azorica, Frangula azorica and Morella faya, three native species of Azores Islands

The aim of this study was to determine the best treatment to maximize seed germination of three native species of the Azores islands (Prunus azorica, Frangula azorica and Morella faya). In all three species the effect of gibberellic acid (GA3) application and cold stratification on seed germination under controlled conditions (light and temperature) was investigated. In particular, seeds of all three species were treated with 500 and 1000 mg L–1 GA3 for 24 hours and were subsequently cold stratified at 3–5°C for 0, 1 and 2 months. In addition, seeds from each species were only cold stratified for 0, 1 and 2 months and also seeds with the endocarp (stones) of P. azorica only were subjected to outdoor stratification from 1 October 2014 up to 28 February 2015. Untreated seeds of all three species exhibited a very low germination percentage, indicating that the seeds of all three species were dormant. For all three species, the germination of seeds untreated with GA3 significantly increased as the cold stratification period increased whereas GA3 application was more effective in improving germination in P. azorica and F. azorica than M. faya seeds. Furthermore, stones of P. azorica that were subjected to outdoor stratification and then transferred to germinate under controlled standard conditions exhibited high and rapid germination.