Forest Edge Research Articles

Resilience of Aboveground Biomass of Secondary Forests Following the Abandonment of Gold Mining Activity in the Southeastern Peruvian Amazon

Amazon rainforests are critical for providing a wide range of ecosystem services. In the Southeastern Peruvian Amazon; however, goldmining activities are causing severe soil degradation and forest loss. We analyzed aboveground biomass (AGB), forest structure, and species diversity recovery during secondary succession in 179 forest plots. Our study provides the first field-based quantification of AGB recovery following the abandonment by two types of goldmining (heavy machinery and suction pumping) in Madre de Dios (Peru). We found that successional secondary forests in areas subjected to suction pumping were more resilient than those in areas subjected to heavy machinery. After 20 years, mean AGB in suction pumping mining areas had reached 56% of reference forest AGB, while in areas of heavy machinery mining it was only 18%. Mining type, stand age, and distance from the forest edge had a significant effect on AGB. The influence of the distance from the forest edge on AGB varies according to mining type because the effects of species diversity on AGB are mediated by the distance from the forest edge. Our results clearly showed the dynamics of AGB recovery across a secondary succession after goldmining, and the contrasting responses of AGB between the two mining types. Our study disentangles the importance of key factors in forest recovery after mining and improves understanding of the resilience of biomass accumulation in these highly degraded ecosystems.

A draft reference genome assembly of California Pipevine, Aristolochia californica Torr.

The California Pipevine, Aristolochia californica Torr., is the only endemic California species within the cosmopolitan birthwort family Aristolochiaceae. It occurs as an understory vine in riparian and chaparral areas and in forest edges and windrows. The geographic range of this plant species almost entirely overlaps with that of its major specialized herbivore, the California Pipevine Swallowtail Butterfly Battus philenor hirsuta. While this species pair is a useful, ecologically well-understood system to study co-evolution, until recently, genomic resources for both have been lacking. Here, we report a new, chromosome-level assembly of A. californica as part of the California Conservation Genomics Project (CCGP). Following the sequencing and assembly strategy of the CCGP, we used Pacific Biosciences HiFi long reads and Hi-C chromatin proximity sequencing technology to produce a de novo assembled genome. Our genome assembly, the first for any species in the genus, contains 531 scaffolds spanning 661 megabase (Mb) pairs, with a contig N50 of 6.53Mb, a scaffold N50 of 42.2Mb, and BUSCO complete score of 98%. In combination with the recently published B. philenor hirsuta reference genome assembly, the A. californica reference genome assembly will be a powerful tool for studying co-evolution in a rapidly changing California landscape.

Unique bird diversity in an Ethiopian church forest

AbstractToday, most of Ethiopia’s church forests are small forest patches surrounded by a degraded and anthropogenically modified landscape, mostly arable land. Nevertheless, these forest islands may still provide valuable habitats for typical forest species. It remains questionable whether these habitat remnants provide sufficient resources for forest species to successfully reproduce and persist in the long run. In this study, we assessed bird species based on point-counts in and around Tara Gedam Church Forest in northern Ethiopia. We observed birds in typical natural evergreen Afromontane forest (forest interior and forest edge) and in anthropogenic habitats, the semi-natural shrublands, agricultural land, and Eucalyptus tree plantations. We assigned ecological and behavioural characteristics to each of the bird species observed. Our results point to a specific bird community restricted to the forest interior and characterized by forest generalists and forest specialist birds. Along the forest edge, a mix of forest generalists and species of the open landscape can be found, creating mixed communities with high species overlap. The highest number of species was observed at the forest edge and in semi-natural shrubland, where both, open-land and forest species were found. On the other hand, the total number of species in the forest interior was comparatively low, with insectivorous and frugivorous typical forest species. Our results underline the fact that even small forest remnants are important for the conservation of forest species, which do not evade surrogate forest habitats.

Edge history modulates the depth of edge influence: Evidence from ground beetles with different feeding traits

Anthropogenic habitat loss and fragmentation are major concerns to conservationists, since these processes lead to species decline and extinction. Edge effect is one of the most important causes of biodiversity losses in fragmented habitats. The depth of edge influence, the distance over which the edge effect penetrates into the adjacent habitat is a central issue, as it fundamentally determines whether the habitat fragment has any remaining core habitat, which is essential for the survival of habitat specialist species. We reviewed 204 edge studies on ground beetles (Coleoptera: Carabidae) of different feeding habits, in forests, one of the habitats most impacted by humans. Meta-analysing 1814 abundance data of 351 ground beetle species from forest edges and their adjoining interiors, we showed that forest edges had significantly higher abundance of herbivorous, omnivorous, and predatory ground beetles than their interiors. Edge history considerably affected the depth of edge influence which on all trophic groups was similar in natural edges and those maintained by agriculture (≤ 10–20 m), while it was wider (> 300 m) when created by forestry or other anthropogenic activities. Consequently, the minimum area of a forest fragment should be ∼ 330 ha in order to keep half of it as core habitat to preserve forest-interior species.

Heterogeneity is key to supporting forest-dweller butterflies

Worldwide, forests are considered biodiversity hotspots. Butterflies are among the surrogate species for forest biodiversity yet in many parts of the world, little is known about the presence or habitat use of forest-dweller butterflies. In this study we aimed to narrow the information gap by applying a time-effective butterfly survey in forests in northeast Türkiye that are surrounded by several prime butterfly areas. The target species were Boloria euphrosyne, Coenonympha arcania, Erebia aethiops, and Satyrium ilicis. The surveys provided 128 records of the species. Random forests models showed that the mean temperature of the warmest month, canopy cover of pine trees, tree size, and managed meadows in or at the edge of forests are important parameters for species occurrence. Nevertheless, the direction of the effects varied between species. Maintaining heterogeneity in forests in terms of the forest variables indicated above and promoting small-scale grassland management in forest openings and edges are important conservation measures for forest-dwelling butterflies. The relevance of the temperature suggests that climate change may have significant effects on the occurrence of forest butterflies. Key words: Habitat use, Hay meadows, Forest structure, Erebia aethiops, Satyrium ilicis, Coenonympha arcania

What are the key factors influencing the dynamics of forest edge? An application of a new forest edge index in the southeast of China

Recent reforestation programs have led to significant increases in forest cover in China; however, they have not been able to halt the process of forest fragmentation. The dynamics of forest fragmentation are still unknown, especially the transitions among forest core (FC), forest edge (FE), and non-forest areas. Taking Fujian Province in southeast China as a case, a new FE index (FEI) was proposed to identify FE, FC, forest patch (FP), matrix edge (ME), matrix core (MC), and forest perforation (FPe) as well. Then the transitions among FC, FE, and non-forest areas was explored; a series of logistic regression models were developed to examine the internal and external, static and dynamic driving patterns of the FE dynamics. The results revealed that the FEI outperforms conventional landscape metrics in identifying FE areas. During the period from 2000 to 2020, FE constituted approximately 41% of the study area. Frequent transition dynamics were observed between FE and other landscape types, accounting for 22% and 19% of the study area during 2000–2010 and 2010–2020, respectively. The internal driving models demonstrated that various landscape types exerted a negative influence on FE expansion. Among these, FPe emerged as a dominant factor, followed by MC, FC, and ME. The external models highlighted the significant influence of elevation, average annual temperature, distance from road, and slope on the mutual transition between FC and FE, while aspect and GDP influenced greatly on the transition from matrix to FE. These findings deepen the understanding of forest fragmentation dynamics and provide valuable insights for forest management.

Native prey, not landscape change or novel prey, drive cougar (Puma concolor) distribution at a boreal forest range edge.

Many large carnivores, despite widespread habitat alteration, are rebounding in parts of their former ranges after decades of persecution and exploitation. Cougars (Puma concolor) are apex predator with their remaining northern core range constricted to mountain landscapes and areas of western North America; however, cougar populations have recently started rebounding in several locations across North America, including northward in boreal forest landscapes. A camera-trap survey of multiple landscapes across Alberta, Canada, delineated a range edge; within this region, we deployed an array of 47 camera traps in a random stratified design across a landscape spanning a gradient of anthropogenic development relative to the predicted expansion front. We completed multiple hypotheses in an information-theoretic framework to determine if cougar occurrence is best explained by natural land cover features, anthropogenic development features, or competitor and prey activity. We predicted that anthropogenic development features from resource extraction and invading white-tailed deer (Odocoileus virgianius) explain cougar distribution at this boreal range edge. Counter to our predictions, the relative activity of native prey, predominantly snowshoe hare (Lepus americanus), was the best predictor of cougar occurrence at this range edge. Small-bodied prey items are particularly important for female and sub-adult cougars and may support breeding individuals in the northeast boreal forest. Also, counter to our predictions, there was not a strong relationship detected between cougar occurrence and gray wolf (Canis lupus) activity at this range edge. However, further investigation is recommended as the possibility of cougar expansion into areas of the multi-prey boreal system, where wolves have recently been controlled, could have negative consequences for conservation goals in this region (e.g. the recovery of woodland caribou [Rangifer tarandus caribou]). Our study highlights the need to monitor contemporary distributions to inform conservation management objectives as large carnivores recover across North America.

Conservation Value to Bats: Assessing Multiple Functional Habitats in a Nature Preserve at the Urban-Agricultural Interface via Temporal Ecology

In grassland ecosystems, agriculture and urbanization are two main anthropogenic disturbances to native fauna. Nature preserves at the urban-agricultural interface may include diverse vegetation habitats, providing opportunities for native fauna. Limited research has examined the conservation value of such preserves to bats. We examined bat activity patterns at multiple temporal scales at Glacier Creek Preserve in Omaha, Nebraska, USA, between 2018 and 2020 via acoustic monitoring to identify what functional habitats it might provide to bats. We placed bat detectors along the forest edge and in the open, restored native prairies and open agricultural fields. A total of nine species were recorded at the preserve, including the endangered Myotis septentrionalis. Foraging activities were recorded for six species. The edge habitat had higher overall acoustic activities for three species (Eptesicus fuscus, Lasiurus borealis, and Lasiurus cinereus) and a higher proportion of foraging activities for two species (Lasiurus borealis and Lasiurus cinereus) than the open habitat. Lasiurus cinereus displayed activity peaks early at night, whereas Lasiurus borealis had activity peaks late. Results suggest that a medium-sized nature preserve at the urban-agricultural interface can provide roosts, commuting corridors, and foraging grounds for different bats. The conservation value of such nature preserves should not be overlooked.

Integrating presence‐only and detection/non‐detection data to estimate distributions and expected abundance of difficult‐to‐monitor species on a landscape‐scale

Abstract Estimating species distribution and abundance is foundational to effective management and conservation. Using an integrated species distribution model that combines presence‐only data from various sources with detection/non‐detection data from structured surveys, we estimated the distribution and expected abundance of three difficult‐to‐monitor mammals of management concern across New York State, namely, coyotes (Canis latrans), bobcats (Lynx rufus) and black bears (Ursus americanus). Three distinct landscape‐scale camera trap surveys provided detection/non‐detection data over 9 years between 2013 and 2021, and we augmented those data with incidental records of our focal species from public repositories. We used an inhomogeneous Poisson point process to construct an integrated model that fit both data types simultaneously. We demonstrate a simple application of spatial point density of all species records in the accessed public databases to inform the thinning process to account for unknown spatial sampling in the presence‐only data, often referred to as the ‘magic covariate’. Using this approach, we examine habitat associations and provide spatially explicit estimates in expected abundance across the entirety of New York State for all three focal species. As expected, coyotes were the most widely distributed and abundant species, with a strong positive association with agricultural land uses. Bobcats exhibited low expected abundance throughout the state and showed positive associations with deciduous forest and forest edge, and a negative association with road density. Finally, we observed considerable spatial variation in abundance of black bears with expected abundance increasing in association with various forest cover and composition covariates and decreasing with crop cover. We present insights into habitat associations and spatial variation in abundance, and provide management implications for each of the species of interest. Synthesis and applications. Our integrated modelling method allows for managers to use citizen sightings combined with detection/non‐detection surveys to estimate robust indices of abundance for both high‐ and low‐density, and wide‐spread versus patchily distributed species. Through comparison with previous studies, we highlight how broad‐scale programmes, such as the statewide efforts to estimate species distributions undertaken here, can benefit substantively from integrated models that leverage additional data (here, incidental records) from a larger region of space, and thus capture more landscape heterogeneity than is plausible within formalized surveys alone.

Where the small things are: Modelling edge effects on mouse lemur population density and distribution in northwestern Madagascar.

Edge effects result from the penetration to varying depths and intensities, of abiotic and biotic conditions from the surrounding non-forest matrix into the forest interior. Although 70% of the world's forests are within 1 km of a forest edge, making edge effects a dominant feature of most forest habitats, there are few empirical data on inter-site differences in edge responses in primates. We used spatially explicit capture-recapture (SECR) models to determine spatial patterns of density for two species of mouse lemurs (Microcebus murinus and Microcebus ravelobensis) in two forest landscapes in northwestern Madagascar. The goal of our study was to determine if mouse lemurs displayed spatially variable responses to edge effects. We trapped animals using Sherman live traps in the Mariarano Classified Forest (MCF) and in the Ambanjabe Forest Fragment Site (AFFS) site within Ankarafantsika National Park. We trapped 126 M. murinus and 79 M. ravelobensis at MCF and 78 M. murinus and 308 M. ravelobensis at AFFS. For M. murinus, our top model predicted a positive edge response, where density increased towards edge habitats. In M. ravelobensis, our top model predicted a negative edge response, where density was lower near the forest edges and increased towards the forest interior. At regional and landscape-specific scales, SECR models estimated different density patterns between M. murinus and M. ravelobensis as a result of variation in edge distance. The spatial variability of our results using SECR models indicate the importance of studying the population ecology of primates at varying scales that are appropriate to the processes of interest. Our results lend further support to the theory that some lemurs exhibit a form of ecological flexibility in their responses to forest loss, forest fragmentation, and associated edge effects.

New fossils of Eocypselus and Primapus from the British London Clay reveal a high taxonomic and ecological diversity of early Eocene swift‐like apodiform birds

We describe new specimens and species of apodiform birds from the early Eocene London Clay of Walton‐on‐the Naze (Essex, UK). In addition to multiple partial skeletons of Eocypselus vincenti Harrison, 1984, three new species of Eocypselus are described as Eocypselus geminus, sp. nov., Eocypselus paulomajor, sp. nov. and Eocypselus grandissimus, sp. nov. The previously unknown quadrate of Eocypselus shares a characteristic derived morphology with the quadrate of the Aegothelidae, Hemiprocnidae and Apodidae, whereas the quadrate of the Trochilidae is very different. We also report a striking disparity of the shapes of the axis vertebra of apodiform birds, which is likely to be of functional significance. Eocypselus and extant Hemiprocnidae and Cypseloidini (Apodidae) exhibit the plesiomorphic morphology, whereas a derived shape characterizes extant Aegothelidae, Apodini and Trochilidae. Furthermore, we describe the first partial skeleton of the earliest aegialornithid species, Primapus lacki Harrison & Walker, 1975, which was previously only known from the humeri of the type series that stem from different sites of the London Clay. The apodiform birds from Walton‐on‐the‐Naze show a considerable taxonomic and ecomorphological diversity, and whereas Eocypselus may have inhabited forest edges and caught insects by sallying flights from perches, Primapus probably was a fast‐flying and more aerial bird.

Retention forestry amplifies microclimate buffering in boreal forests

Retention forestry is increasingly adopted as an alternative to clearcutting practices and involves retaining structural and compositional complexity (e.g., living and dead trees) from preharvest to postharvest. Past studies have examined the role of retention forestry in supporting various ecosystem functions and biodiversity, whilst its microclimate buffering capacity has been largely neglected. We investigated the microclimates and the underlying mechanisms of retention forests relative to clearcuts and old forests in a boreal forest landscape in central Sweden. We found that both air temperature and vapour pressure deficit (VPD) differed significantly between the forest types. Old forests consistently exhibited the most buffered forest microclimates, followed by retention forests, while clearcuts displayed the lowest. Basal area and canopy cover were identified as the key determinants influencing air temperature and VPD across the forest types. Retention practices can also impact a stand's microclimates. Specifically, maintaining diverse tree species had the potential to lower the stand's maximum temperature, given its positive association with canopy cover. Large volumes of lying deadwood were found to be negatively correlated with both basal area and canopy cover, likely contributing to increased maximum temperatures. Furthermore, standing deadwood directly lowered the maximum temperature within forest stands. Finally, edge effects were observed in the retention forests, with south-facing edges experiencing significantly higher maximum temperature and VPD compared to north-facing edges and forest interiors. These south-facing edge effects were positively associated with the difference in lying deadwood volumes between forest edges and interiors. Our findings support the positive influence of retention practices on a stand's microclimate buffering, achieved through preserving diverse tree species, standing deadwood, and implementing measures to prevent severe wind-induced tree mortality, particularly in south-facing edges (e.g. creating south-facing buffer zones). Forest managers and policy makers can utilize these results to minimize the climate-change impacts on below-canopy biodiversity and functioning.

Importance of Habitat Context in Modelling Risk Maps for Two Established Invasive Alien Plant Species: The Case of Ailanthus altissima and Phytolacca americana in Slovenia (Europe)

Forests are important ecosystems that face threats from climate change and global environmental shifts, with invasive alien plant species being a significant concern. Some of these invasive species have already become established, while others are in the process of naturalisation. Although forests are a relatively stable ecosystem, extreme weather events increase their vulnerability to change, and clearings left after natural disturbances are particularly susceptible to invasion by alien plant species (IAPS). We created risk maps of two species that have spread rapidly in the last decade: American pokeweed (Phytolacca americana) and the tree of heaven (Ailanthus altissima). We prepared a generalised linear model based on the occurrence data collected within the LIFE ARTEMIS project. Eleven environmental variables were used to determine habitat characteristics. We constructed two models for each species: one covering the entirety of Slovenia and the other specifically for the forested areas in Slovenia, with the latter incorporating forest-specific variables (such as forest sanitation felling and monocultures). We observed the presence of both species at lower altitudes and in close proximity to water sources. American pokeweed tends to occur nearer to railways, while the presence of the tree of heaven is associated with areas lacking carbonate parent material and influenced by land use patterns. In forested areas, the occurrence of American pokeweed is influenced by forest habitat characteristics, such as disturbances caused by extreme weather events or the prevalence of Norway spruce monocultures. In contrast, the occurrence of the tree of heaven is influenced by more general environmental variables, such as altitude and proximity to railways. Consequently, we have generated risk maps for the entirety of Slovenia and separately for forested areas, both of which indicate similar levels of risk, particularly for the tree of heaven. The risk map for American pokeweed highlights numerous vulnerable areas, especially forest edges, which are highly susceptible to invasion. Furthermore, there is a higher likelihood of this species occurring in areas that have undergone sanitation felling. This study suggests that the production of risk maps of IAPS could be improved by focussing on habitat types and taking into account habitat-specific variables. This approach could enhance the early detection and management of these invasive species.

Recent advances and challenges in monitoring and modeling of disturbances in tropical moist forests

Tropical moist forests have been severely affected by natural and anthropogenic disturbances, leading to substantial changes in global carbon cycle and climate. These effects have received great attention in scientific research and debates. Here we review recent progress on drivers and ecological impacts of tropical moist forest disturbances, and their monitoring and modeling methods. Disturbances in tropical moist forests are primarily driven by clearcutting, selective logging, fire, extreme drought, and edge effects. Compound disturbances such as fire and edge effects aggravate degradation in the edge forests. Drought can result in terrestrial carbon loss via physiological impacts. These disturbances lead to direct carbon loss, biophysical warming and microclimate change. Remote sensing observations are promising for monitoring forest disturbances and revealing mechanisms, which will be useful for implementing disturbance processes in dynamic vegetation models. Yet, constrained spatiotemporal coverages and resolutions limit the application of these data in process-based models. It is also challenging to represent physical processes derived from fine-resolution remote sensing data in coarse-resolution models. We highlight the need to continuously integrate new datasets and physical processes in forest disturbance modeling to advance understanding of disturbance patterns and impacts. Interactions and impacts of climate change and anthropogenic activities should also be considered for modeling and assessing feedbacks of tropical moist forest disturbances.

Vegetational and Structural Features of Forest Clearings in Plitvice Lakes National Park

The impact of various ecological factors, biogeographical position and both former and current anthropogenic activity in Plitvice Lakes National Park greatly influenced the development of different habitat types, including forest clearings. Due to the insufficient knowledge of this habitat type, based primarily on general descriptions within the National Habitat Classification of the Republic of Croatia (NN 27/2021, NN 101/2022), this paper deals with presenting their vegetational and structural characteristics in the national park area. The following taxonomic keys were used to determine plant species: Tutin et al. (1964-1980), Pignatti (1982), Javorka and Csapody (1991) and Martinčič et al. (1999). Furthermore, scientific nomenclature of plant species was conducted using Flora Croatica Database (Nikolić 2012), while threat status was aligned by the Red Book of Vascular Flora of Croatia (Nikolić and Topić 2005). Also, protection level was adjusted according to the Regulation on strictly protected species (NN 144/2013, NN 73/2016). Spectrum of life forms and chorological types were aligned according to Pignatti (2005). Vegetation was studied in accordance with the principles of the Braun-Blanquet approach (Braun-Blanquet 1964). Together with the basic parameters of the selected plots, the research also included the collection of structural parameters of forest clearings according to Medak et al. (2023). Based on conducted research, a total of 98 plots of forest clearing habitats were established with a total of five different forest clearing communities. The largest number of forest clearing communities belonged to Salicetum capreae, followed by Eupatorietum cannabini, Atropetum bella-donae, Telekium speciosae and Rubetum idaei. A total of 257 species of vascular plants were identified in the area and classified into 60 families. The most represented family was Asteraceae, while the highest relative representation of life-forms belonged to hemicryptophytes (H). Furthermore, the most represented chorologycal type in the area was Eurasian (20.6%). The habitat type contained a total of 11 strictly protected (SZ), 6 nearly threatened (NT), 3 vulnerable (VU), 2 data-deficient (DD) and 4 endemic species. In addition, the largest number of plots had an anthropogenic origin, irregular type (shape), occupied a small area (less than 1000 m2) and were located along the edges of both forests and forest roads. The results of this paper represent the first vegetational and structural data of forest clearings in the national park area which contribute to an expansion of our knowledge and understanding of this habitat type, and form a starting point for the necessary future research.

Internal and edge-effect environmental monitoring to assess the threats facing intact tropical peat swamp forest in Central Kalimantan

Peat swamp forest (PSF) provides vital environmental benefits, including carbon storage. However, almost half of the Indonesia’s PSF areas are extensively degraded. Internal threats such as drainage contribute to peat drying, vegetation damage and heightened fire risk. Equally, forest edges are threatened from human activity and fire spread, leading to forest edge regression. This study assesses biophysical changes within an area of intact tropical PSF and along their edges in Central Kalimantan. To assess these threats, we established seven transects perpendicular to the forest edge, transitioning from degraded to intact forest. Forty-nine dipwells, and three loggers were installed to assess drainage and subsidence. We established seed traps and seedling plots along three transects at three distances from the forest edge (three replicates per distance) to assess forest edge regeneration potential. Furthermore, we are analysing historic remote sensing data from the last two decades to study land cover change and forest edge loss related to fire. Equipment was established February 2022, with data collection underway for 12 months. Here, we present our initial findings. The results will provide quantitative and qualitative data analysis to describe potential threat levels facing this forest and give recommendations for developing a targeted conservation action plan.

Experimental warming and nitrogen deposition in clear‐cuts and forest edges: Assessing impacts on plant communities and tree seedling performance

AbstractQuestionsDo nitrogen deposition and climate warming affect tree seedlings and plant communities in different habitats? In these habitats, how do microenvironments, including soil properties and, when applicable, edge effects relate to plant performance?LocationThe University of British Columbia Malcolm Knapp Research Forest, Maple Ridge, British Columbia, Canada.MethodsWe assessed performance of Pseudotsuga menziesii (Mirb.) Franco, Thuja plicata Donn ex D. Don and Tsuga heterophylla (Raf.) Sarg. planted tree seedlings and associated vascular plant communities. Performance of tree seedlings (height) and under vascular plant communities (percent cover) were examined in an experiment with warming (open‐top chambers) and nitrogen deposition (ammonium nitrate applied at 10 kg N ha−1 year−1) treatments applied to subplots in six forest edges and six clear‐cuts (N = 298 total subplots).ResultsIn clear‐cuts, tree seedling height increased with experimental warming and differed among species, and vascular plant cover increased with warming. In clear‐cuts, species identity, not soil variables, was a strong predictor of height, and plant cover was negatively related to pH. In forest edges, edge position and some soil variables were related to height, but not plant cover. There were no interaction effects found between experimental nitrogen deposition and warming.ConclusionsOur results suggest that moderate warming can enhance tree seedling height and understorey vascular plant cover in clear‐cuts in Pacific Northwest coastal ecosystems, but low nitrogen deposition may not have an effect alone or synergistically with warming.

Forest history from a single tree species perspective: natural occurrence, near extinction and reintroduction of European yew (Taxus baccata L.) on the Darss-Zingst peninsula, southern Baltic Sea coast

AbstractThe forests along the southern Baltic Sea coast harbour some stands of the rare and endangered European yew (Taxus baccata L.), which are hypothesised to be autochthonous. Using the example of an occurrence on the Darss-Zingst peninsula, the population dynamics of the yew since the late Holocene are interdisciplinarily investigated and linked to the forest history of this area. Pollen analysis shows that yew has been present in the study area for at least 2600 years and thus indeed represents an autochthonous tree species in the area. The yew was probably originally part of a second tree storey and of forest margins within a mixed forest mainly consisting of several deciduous tree species and Scots pine. Historical evidence reveals that yew was still occurring in the forest in the middle of the eighteenth century, but then had nearly disappeared by the end of the nineteenth century. This was caused by several factors including forest grazing by livestock, high game populations and clear-cutting. First replanting of yew took place in the 1930s/1940s and 1950s/1960s, followed by planting campaigns in the 1990s and 2000s. Planting material from local and regional autochthonous relict populations was used, at least in part. The current yew population mainly comprises young individuals with a total number of ca. 1300 trees. It has thus been possible here to re-establish an autochthonous yew occurrence that was nearly extinct in historical times. This local example of targeted re-enrichment of native tree diversity may also encourage further measures to give this species a new chance again elsewhere in the wider region.

Precipitation explains Wood Thrush (Hylocichla mustelina) occupancy patterns in Northern Costa Rica

Introduction: The Wood Thrush is a migratory bird that has experienced dramatic declines in its populations in recent decades. This species overwinters in forest fragments with intermediate levels of habitat modification in Central America. However, more studies detailing the use of remnant forests through time are needed to elucidate the threats this species faces in the wintering grounds. Objective: To understand the effects of environmental and forest structure variables on the occupancy of Wood Thrush in Northern Costa Rica. Methods: The study area was the Área de Conservación Guanacaste (ACG), located in Northern Costa Rica, in December 2016, and during the 2018-2019 migration season. We estimated Wood Thrush occupancy and detection probability in four locations of ACG (dry forest, cloud forest, and two locations in the wet forest) using single-season occupancy models. We also estimated Wood Thrush occupancy and probability of persistence in different months in three vegetation types (open area, secondary forest, and old-growth forest) in the wet forest of ACG using a multi-season occupancy model approach. Results: Wood Thrush occupancy was best described by precipitation in the four locations of the ACG; the probability of occupancy increased with precipitation. The average occupancy of Wood Thrushes varied with vegetation type: open area with shrubs and forest edge (0.69 ± 0.09), secondary forest (0.46 ± 0.1), and old-growth forest (0.61 ± 0.1). Wood Thrush probability of persistence responded partially to changes in precipitation, with an unexpected increase in persistence when the rainfall continued decreasing in the season. Conclusion: Wood Thrush occupancy was best predicted by changes in precipitation considering a larger spatial scale. Its probability of persistence partially varied with precipitation. An increase in persistence closer to Spring migration might be explained by the start of the breeding season of resident birds, potentially reducing territorial conflicts and conserving energy before migration. The long-term protection of wet forests in Northern Costa Rica is of paramount importance for the conservation of Wood Thrushes in their wintering grounds.

Trade-offs in biodiversity and ecosystem services between edges and interiors in European forests.

Forest biodiversity and ecosystem services are hitherto predominantly quantified in forest interiors, well away from edges. However, these edges also represent a substantial proportion of the global forest cover. Here we quantified plant biodiversity and ecosystem service indicators in 225 plots along forest edge-to-interior transects across Europe. We found strong trade-offs: phylogenetic diversity (evolutionary measure of biodiversity), proportion of forest specialists, decomposition and heatwave buffering increased towards the interior, whereas species richness, nectar production potential, stemwood biomass and tree regeneration decreased. These trade-offs were mainly driven by edge-to-interior structural differences. As fragmentation continues, recognizing the role of forest edges is crucial for integrating biodiversity and ecosystem service considerations into sustainable forest management and policy.