Local Extinction Of Species Research Articles

Temporal variability of sea surface temperature affects marine macrophytes range retractions as well as gradual warming

Record mean sea surface temperatures (SST) during the past decades and marine heatwaves have been identified as responsible for severe impacts on marine ecosystems, but the role of changes in the patterns of temporal variability under global warming has been much less studied. We compare descriptors of two time series of SST, encompassing extirpations (i.e. local extinctions) of six cold-temperate macroalgae species at their trailing range edge. We decompose the effects of gradual warming, extreme events and intrinsic variability (e.g. seasonality). We also relate the main factors determining macroalgae range shifts with their life cycles characteristics and thermal tolerance. We found extirpations of macroalgae were related to stretches of coast where autumn SST underwent warming, increased temperature seasonality, and decreased skewness over time. Regardless of the species, the persisting populations shared a common environmental domain, which was clearly differentiated from those experiencing local extinction. However, macroalgae species responded to temperature components in different ways, showing dissimilar resilience. Consideration of multiple thermal manifestations of climate change is needed to better understand local extinctions of habitat-forming species. Our study provides a framework for the incorporation of unused measures of environmental variability while analyzing the distributions of coastal species.

Sharp declines in observation and capture rates of Amazon birds in absence of human disturbance

Across the globe, unprecedented declines have been reported across a range of taxa. Among the most well documented are declines in bird populations, with most declines attributable to human activities such as deforestation and other alterations to habitats. There is increasing evidence that bird populations also have declined at sites within large expanses of relatively undisturbed lowland tropical forest, such as in Amazonia. Causes of such declines likely are varied and may be related to direct or indirect effects of climate change. Here, we use mist-net data and direct observations to examine changes in bird numbers over a 22-yr period on two 100-ha study plots in an Amazonian lowland forest of eastern Ecuador. As previously reported, capture rates experienced large declines from 2009 on; observation rates also showed large declines through 2013 but subsequently have shown no consistent trend up or down. Overall capture rates and observation rates are now approximately half the rates during the first decade. Most foraging guilds also declined over time, with declines particularly pronounced among insectivorous groups. With few exceptions, patterns of change were similar between plots suggesting a more general response rather than responses to local factors on each plot. Capture rates and observation rates of ∼90% of the most common species in both understory and canopy were lower during the latter part of the study, with only a few species (∼10%) showing increases. Similarly, large declines were seen in both canopy and understory mixed-species flocks. Large declines in bird numbers have been noted in other tropical sites that have conducted long-term population studies, including Panama and Brazil, suggesting a response to large-scale factors, such as climate change. While not yet documented, the consequences of losing approximately 50% of population abundance are likely substantial and could result in local extinction of rare species, altered species interactions and social organization, as well as declining ecological function and biotic integrity of these tropical forest ecosystems.

Restoring the threatened Scalesia forest: insights from a decade of invasive plant management in Galapagos

Island forests are becoming increasingly fragmented and colonized by invasive species, which can eventually lead to local species extinctions. In the Galapagos Islands, invasive species pose a serious extinction threat to the endemic daisy tree Scalesia pedunculata, formerly the dominant habitat-forming species of the unique Scalesia forest. This forest has been reduced to fragments due to land use changes in the past and is now increasingly invaded by introduced plants. We conducted a field experiment on Santa Cruz Island to assess the impacts of blackberry (Rubus niveus) and two other invasive plant species, Cestrum auriculatum and Tradescantia fluminensis, as well as the effects of the removal of two of these (R. niveus and C. auriculatum) on cover, composition and diversity of the resident plant communities. Particular attention was paid to effects of the invasive species on the S. pedunculata population. Annual vegetation monitoring was carried out in a total of 34 permanent plots (10 m × 10 m) over 10 years (2014–2023), using the line-intercept method. Seventeen of these plots were established in an invaded area and 17 plots in an area with continuous invasive plant removal since 2014. Results indicated that there were significant changes in both the species composition of the plant communities and average percent cover of species over time, comparing removal plots with invaded plots. Species composition in removal plots changed significantly more than in invaded plots, towards a plant community with greater percent cover of endemic species. A significant negative relationship between the three invasive species and cover of S. pedunculata suggested that multiple invader species may have additive negative impacts. Natural recruitment of S. pedunculata by seeds was observed in the removal but not in the invaded plots. These results, as well as the striking decrease of 71% in cover of adult S. pedunculata in the invaded plots indicate that this threatened species will be driven to local extinction on Santa Cruz Island, Galapagos, in less than 20 years if invasive plant species are not removed on a large scale.

Association between anthropization and rodent reservoirs of zoonotic pathogens in Northwestern Mexico.

The world is facing a major pulse of ecological and social changes that may favor the risk of zoonotic outbreaks. Such risk facilitation may occur through the modification of the host's community diversity and structure, leading to an increase in pathogen reservoirs and the contact rate between these reservoirs and humans. Here, we examined whether anthropization alters the relative abundance and richness of zoonotic reservoir and non-reservoir rodents in three Socio-Ecological Systems. We hypothesized that anthropization increases the relative abundance and richness of rodent reservoirs while decreasing non-reservoir species. We first developed an Anthropization index based on 15 quantitative socio-ecological variables classified into five groups: 1) Vegetation type, 2) Urbanization degree, 3) Water quality, 4) Potential contaminant sources, and 5) Others. We then monitored rodent communities in three regions of Northwestern Mexico (Baja California, Chihuahua, and Sonora). A total of 683 rodents of 14 genera and 27 species were captured, nine of which have been identified as reservoirs of zoonotic pathogens (359 individuals, 53%). In all regions, we found that as anthropization increased, the relative abundance of reservoir rodents increased; in contrast, the relative abundance of non-reservoir rodents decreased. In Sonora, reservoir richness increased with increasing anthropization, while in Baja California and Chihuahua non-reservoir richness decreased as anthropization increased. We also found a significant positive relationship between the anthropization degree and the abundance of house mice (Mus musculus) and deer mice (Peromyscus maniculatus), the most abundant reservoir species in the study. These findings support the hypothesis that reservoir species of zoonotic pathogens increase their abundance in disturbed environments, which may increase the risk of pathogen exposure to humans, while anthropization creates an environmental filtering that promotes the local extinction of non-reservoir species.

The land snail fauna of Batu Kudik, isolated limestone outcrop near Simunjan, Sarawak, Malaysian Borneo (Mollusca, Gastropoda).

The present study provides a checklist of land snails collected from Batu Kudik, a small and isolated limestone outcrop in Simunjan, Sarawak. A total of 24 species of land snails, representing 18 genera and 14 families were recorded, including one newly-described subspecies. The most species-rich of the families in Batu Kudik are Diplommatinidae (17%) and Chronidae (17%) with four recorded species from each of the families. Based on our analysis, Plectostomawallaceikudikense subsp. nov., Opisthostomajavanica and Georissapyrrhoderma were identified as the most abundant land snails at this isolated outcrop, whereas Diplommatinaonyx and Everettiaminuta were recorded as the least abundant. All of the land snails at Batu Kudik were exclusively found sheltered between limestone boulders, underscoring the critical role of this outcrop as their refuge for survival. Consequently, conserving this biodiversity-rich limestone area becomes paramount to prevent the local extinction of these land snail species and possibly other organisms that depend on the unique attributes of the limestone for their survival. We also provide detailed descriptions of Plectostomawallaceikudikense, a new subspecies of the genus Plectostoma which is endemic to Batu Kudik. A description of a new subspecies Plectostomawallaceikudikense subsp. nov.

The effect of urbanization and temperature on thermal tolerance, foraging performance, and competition in cavity-dwelling ants.

Human disturbance including rapid urbanization and increased temperatures can have profound effects on the ecology of local populations. Eusocial insects, such as ants, have adapted to stressors of increasing temperature and urbanization; however, these evolutionary responses are not consistent among populations across geographic space. Here we asked how urbanization and incubation temperature influence critical thermal maximum (CTmax) and various ecologically relevant behaviors in three ant species in urban and rural locations in Worcester, MA, USA. We did this by incubating colonies of three species of cavity dwelling ant (Aphaenogaster picea, Tapinoma sessile, and Temnothorax longispinosus) from 2 habitat types (Rural and Urban), for 60-days at multiple temperatures. We found that incubation temperature, urbanization, and species of ant all significantly affected overall colony critical thermal maximum. We also found that recruitment time, colonization time, and defense response were significantly affected by incubation temperature and varied between species of ant, while recruitment and colonization time were additionally affected by urbanization. These variable changes in performance and competitive traits across species suggest that responses to urbanization and shifting temperatures are not universal across species. Changes in behavioral responses caused by urbanization may disrupt biodiversity, creating unusual competitive environments as a consequence of natural adaptations and cause both direct and indirect mechanisms for which human disturbance can lead to local species extinction.

Urbanization reduces gut bacterial microbiome diversity in a specialist ground beetle, Carabus convexus.

Urbanization is rapidly shaping and transforming natural environments, creating networks of modified land types. These urbanization-driven modifications lead to local extinctions of several species, but the surviving ones also face numerous novel selection pressures, including exposure to pollutants, habitat alteration, and shifts in food availability and diversity. Based on the assumption that the environmental pool of microorganisms is reduced in urban habitats due to habitat alteration, biodiversity loss, and pollution, we hypothesized that the diversity of bacterial microbiome in digestive tracts of arthropods would be lower in urban than rural habitats. Investigating the gut bacterial communities of a specialist ground beetle, Carabus convexus, in forested rural versus urban habitats by next generation high-throughput sequencing of the bacterial 16S rRNA gene, we identified 3839 bacterial amplicon sequence variants. The composition of gut bacterial samples did not significantly differ by habitat (rural vs. urban), sex (female vs. male), sampling date (early vs. late spring), or their interaction. The microbiome diversity (evaluated by the Rényi diversity function), however, was higher in rural than urban adults. Our findings demonstrate that urbanization significantly reduced the diversity of the gut bacterial microbiome in C. convexus.

Evaluating plant lineage losses and gains in temperate forest understories: a phylogenetic perspective on climate change and nitrogen deposition.

Global change has accelerated local species extinctions and colonizations, often resulting in losses and gains of evolutionary lineages with unique features. Do these losses and gains occur randomly across the phylogeny? We quantified: temporal changes in plant phylogenetic diversity (PD); and the phylogenetic relatedness (PR) of lost and gained species in 2672 semi-permanent vegetation plots in European temperate forest understories resurveyed over an average period of 40 yr. Controlling for differences in species richness, PD increased slightly over time and across plots. Moreover, lost species within plots exhibited a higher degree of PR than gained species. This implies that gained species originated from a more diverse set of evolutionary lineages than lost species. Certain lineages also lost and gained more species than expected by chance, with Ericaceae, Fabaceae, and Orchidaceae experiencing losses and Amaranthaceae, Cyperaceae, and Rosaceae showing gains. Species losses and gains displayed no significant phylogenetic signal in response to changes in macroclimatic conditions and nitrogen deposition. As anthropogenic global change intensifies, temperate forest understories experience losses and gains in specific phylogenetic branches and ecological strategies, while the overall mean PD remains relatively stable.

Enhancing temperate grassland diversity and functionality: Crafting seed mixtures to align stakeholder interests and to increase establishment success

Grassland biodiversity is positively correlated to ecosystem productivity and resilience that secure net gains and functionality of such systems. Land-use change of grasslands is associated with local extinction of species and declining ecosystem services. Hence, the design of more diverse seed mixtures is crucial for successful species reintroduction and grassland functionality. Thus, we conducted a systematic review of the scientific literature on temperate grassland reseeding during the past 30 years. This generated a knowledge base of reseeding methods and success, and revealed knowledge gaps and mismatches in the design of seed mixtures created by different stakeholders. From 201 published studies, we extracted information on stakeholder groups and focus, starting conditions, species selection for the mixtures, and monitoring of reseeded grasslands. Our review showed: (i) There were five stakeholder groups with varying focus along a gradient of biodiversity control; in turn, the starting conditions of reseeded sites changed along a gradient of dissimilarity in relation to reference grasslands. (ii) The design of the grassland mixtures varied in species composition, seed origin, and seed quality. (iii) While mixtures aiming at a certain vegetation structure and biomass showed high establishment success, grassland reseeding with a biodiversity focus was less successful. (iv) The design of seed mixtures changed significantly during the past decades, since species numbers in mixtures, i.e., the biodiversity focus, and the proportion of forbs, which indicates lower productivity, decreased in most stakeholder groups. (v) The number of ecosystem services monitored, i.e., the proportion of multiple-to-single ecosystem services, also declined for most stakeholders. Such findings indicate a narrowing focus on specific grassland composition and functions by stakeholders, in contrast to current trends toward multiple ecosystem services. The different establishment success of stakeholders conducting temperate grassland reseeding call for knowledge transfer among groups to achieve higher establishment success in restoration and conservation professionals as seen among turf managers and farmers. Overall, the design of grassland mixtures needs to be revisited in the face of the current biodiversity losses and climate change.

Demography of the understory herb Heliconia acuminata (Heliconiaceae) in an experimentally fragmented tropical landscape.

Habitat fragmentation remains a major focus of research by ecologists decades after being put forward as a threat to the integrity of ecosystems. While studies have documented myriad biotic changes in fragmented landscapes, including the local extinction of species from fragments, the demographic mechanisms underlying these extinctions are rarely known. However, many of them-especially in lowland tropical forests-are thought to be driven by one of two mechanisms: (1) reduced recruitment in fragments resulting from changes in the diversity or abundance of pollinators and seed dispersers or (2) increased rates of individual mortality in fragments due to dramatically altered abiotic conditions, especially near fragment edges. Unfortunately, there have been few tests of these potential mechanisms due to the paucity of long-term and comprehensive demographic data collected in both forest fragments and continuous forest sites. Here we report 11 years (1998-2009) of demographic data from populations of the Amazonian understory herb Heliconia acuminata (LC Rich.) found at Brazil's Biological Dynamics of Forest Fragments Project (BDFFP). The data set comprises >66,000 plant × year records of 8586 plants, including 3464 seedlings established after the first census. Seven populations were in experimentally isolated fragments (one in each of four 1-ha fragments and one in each of three 10-ha fragments), with the remaining six populations in continuous forest. Each population was in a 50 × 100 m permanent plot, with the distance between plots ranging from 500 m to 60 km. The plants in each plot were censused annually, at which time we recorded, identified, marked, and measured new seedlings, identified any previously marked plants that died, and recorded the size of surviving individuals. Each plot was also surveyed four to five times during the flowering season to identify reproductive plants and record the number of inflorescences each produced. These data have been used to investigate topics ranging from the way fragmentation-related reductions in germination influence population dynamics to statistical methods for analyzing reproductive rates. This breadth of prior use reflects the value of these data to future researchers. In addition to analyses of plant responses to habitat fragmentation, these data can be used to address fundamental questions in plant demography and the evolutionary ecology of tropical plants and to develop and test demographic models and tools. Though we welcome opportunities to collaborate with interested users, there are no restrictions on the use of this data set. However, we do request that those using the data for teaching or research purposes inform us of how they are doing so and cite this paper and the data archive when appropriate. Any publication using the data must also include a BDFFP Technical Series Number in the Acknowledgments. Authors can request this series number upon the acceptance of their article by contacting the BDFFP's Scientific Coordinator or E. M. Bruna.

The pattern of declines and local extinctions of endemic inland Lepidium species in the eastern South Island

The pattern of declines and local extinctions of endemic inland Lepidium species in the eastern South Island

Soil community composition in dynamic stages of semi-natural calcareous grassland.

European dry thin-soil calcareous grasslands (alvars) are species-rich semi-natural habitats. Cessation of traditional management, such as mowing and grazing, leads to shrub and tree encroachment and the local extinction of characteristic alvar species. While soil microbes are known to play a critical role in driving vegetation and ecosystem dynamics, more information is needed about their composition and function in grasslands of different dynamic stages. Here we assess the composition of soil fungal, prokaryotic, and plant communities using soil environmental DNA from restored alvar grasslands in Estonia. The study areas included grasslands that had experienced different degrees of woody encroachment prior to restoration (woody plant removal and grazing), as well as unmanaged open grasslands. We found that, in general, different taxonomic groups exhibited correlated patterns of between-community variation. Previous forest sites, which had prior to restoration experienced a high degree of woody encroachment by ectomycorrhizal Scots pine, were compositionally most distinct from managed open grasslands, which had little woody vegetation even prior to restoration. The functional structure of plant and fungal communities varied in ways that were consistent with the representation of mycorrhizal types in the ecosystems prior to restoration. Compositional differences between managed and unmanaged open grasslands reflecting the implementation of grazing without further management interventions were clearer among fungal, and to an extent prokaryotic, communities than among plant communities. While previous studies have shown that during woody encroachment of alvar grassland, plant communities change first and fungal communities follow, our DNA-based results suggest that microbial communities reacted faster than plant communities during the restoration of grazing management in alvar grassland. We conclude that while the plant community responds faster to cessation of management, the fungal community responds faster to restoration of management. This may indicate hysteresis, where the eventual pathway back to the original state (grazed ecosystem) differs from the pathway taken towards the alternative state (abandoned semi-natural grassland ecosystem).

Functional traits drive the fate of Orthoptera in urban areas

Abstract The replacement of natural areas due to urbanisation represents a major threat to wildlife. Wild species may be classified according to their response towards urban areas. Such responses lead to persistence (exploiters and tolerant) or local extinction (avoiders) of species within cities, which in turn contributes to shaping the assemblages found therein, usually according to specific sets of ecological and morphological traits. Here, we focus on Orthoptera as a model group to test hypotheses on the relationships between species' traits and persistence in urban environments, using the city of Rome, Italy, as study area. By compiling and comparing species checklists for two distinct time frames, we assessed assemblage variation across the last three decades and revealed that local extinction of Orthoptera in urban areas is trait‐biased. Species with low mobility and fertility, and narrower—more specialised—climatic niches showed higher probability of local extinction. Our results point at both climate and land use changes as potentially major drivers of orthopterans' local extinction in urban areas, suggesting that strategies to increase natural habitat preservation and connectivity, and mitigate climate‐change induced events, may both prove effective in sustaining richer insect communities within urban areas.

Incorporating global change reveals extinction risk beyond the current Red List

Global changes over the past few decades have caused species distribution shifts and triggered population declines and local extinctions of many species. The International Union for Conservation of Nature (IUCN) Red List of Threatened Species (Red List) is regarded as the most comprehensive tool for assessing species extinction risk and has been used at regional, national, and global scales. However, most Red Lists rely on the past and current status of species populations and distributions but do not adequately reflect the risks induced by future global changes. Using distribution maps of >4,000 endemic woody species in China, combined with ensembled species distribution models, we assessed the species threat levels under future climate and land-cover changes using the projected changes in species' suitable habitats and compared our updated Red List with China's existing Red List. We discover an increased number of threatened species in the updated Red List and increased threat levels of >50% of the existing threatened species compared with the existing one. Over 50% of the newly identified threatened species are not adequately covered by protected areas. The Yunnan-Guizhou Plateau, rather than the Hengduan Mountains, is the distribution center of threatened species on the updated Red Lists, as opposed to the threatened species on the existing Red List. Our findings suggest that using Red Lists without considering the impacts of future global changes will underestimate the extinction risks and lead to a biased estimate of conservation priorities, potentially limiting the ability to meet the Kunming-Montreal global conservation targets.

Dead Shells Bring to Life Baselines for Conservation: Case Studies from The Bahamas, Southern California, and Wisconsin, USA

We are living in a time of rapid biodiversity loss. Numerous studies have shown that modern extinction rates are higher than pre-human background rates. However, these studies of biodiversity decline almost exclusively focus on large vertebrates. The scientific community lacks the sufficient long-term records necessary to track biodiversity loss for many invertebrate taxa. However, aquatic, benthic, and skeletonized invertebrates have the advantage of leaving a long-term record that can readily be sampled in conjunction with living communities because the mineralized skeletons accumulate in the very same sediments in which the animals that produced them once lived. These not-quite-fossil “death assemblages” contain an underutilized record for long-term monitoring. Here, we leverage three case studies of calcareous micro- and macro-faunal remains from three aquatic environments spanning two gradients: freshwater to fully marine and polluted to pristine and remediated. We compared the death assemblages to living assemblages in these case studies using Spearman’s rho and the Jaccard–Chao agreement to determine the degree of fidelity. Death assemblages of lacustrine, calcareous microcrustaceans (Ostracoda), collected from lakes in The Bahamas and Wisconsin, USA, faithfully record human impacts, both for degradation and remediation, as determined by a mismatch in the live–dead comparisons. Likewise, the live–dead comparisons of calcareous marine macrofauna (Bivalvia) from the southern California shelf also indicate human impact, including pollution and remediation. These case studies demonstrate how death assemblages can be used to gauge the changes in community assembly and population structures at local and regional scales, even in the absence of a systemic monitoring program. Conservation, restoration, and biomonitoring efforts would benefit from the inclusion of live–dead comparisons of taxa with easily fossilized, identifiable parts. Live–dead studies, such as those presented in these case studies, can be used as tools for recognizing targets and establishing baselines for conservation, tracking community responses to remediation efforts, and identifying local species extinctions.

The biodiversity benefits of marine protected areas in well-regulated fisheries

There is long-running debate concerning the conservation benefits of marine protected areas (MPAs) in seascapes that are already ‘well-regulated’ by other forms of fisheries management. Resolving this issue is particularly important given recent calls for expanding MPA coverage. Here, we adapt an influential model from agriculture – the land sparing/sharing framework – to an archetypal managed trawl fishery to determine how catches can be obtained at least cost to biodiversity in such seascapes. This new sea sparing/sharing framework fixes catch across scenarios so that fishing effort displacement is not overlooked. We find that a sparing strategy combining MPAs with fishing effort regulation is best for biodiversity when avoiding the local extinction of sensitive species is a priority. However, if there are no sensitive species, or if biodiversity is instead measured in a way that emphasises species abundances, then a sharing strategy relying on fishing effort regulation alone instead prevails. Extending these findings globally to ‘well-regulated’ crustacean trawl fisheries, we find that ≈72% may benefit from no-trawl MPAs (≈57–100% depending on the methodology chosen). However, these MPAs could also necessitate increased fishing effort if catches are to be maintained. Our framework thus suggests that whether MPAs increase biodiversity in a well-regulated seascape depends heavily on the presence of highly sensitive species there, as well as conservation and management priorities.

Long-term community shifts driven by local extinction of an iconic foundation species following an extreme marine heatwave.

Gradual ocean warming combined with stronger marine heatwaves (MHWs) can reduce abundances of foundation species that control community structures, biodiversity, and ecosystem functioning. However, few studies have documented long-term succession trajectories following the more extreme events that cause localized extinctions of foundation species. Here, we documented long-term successional changes to marine benthic communities in Pile Bay, New Zealand, following the Tasman 2017/18 MHW, which caused localized extinctions of dominant southern bull kelp (Durvillaea sp.). Six years on, multiscale annual and seasonal surveys show no sign of Durvillaea recolonization. Instead, the invasive annual kelp (Undaria pinnatifida), rapidly colonized areas previously dominated by Durvillaea, followed by large changes to the understory community, as Durvillaea holdfasts and encrusting coralline algae were replaced by coralline turf. Between 3 and 6 years after the total loss of Durvillaea, smaller native fucoids colonized in high densities. Although Undaria initially colonized plots throughout Durvillaea's tidal range, later in the succession Undaria only retained dominance in the lower intertidal zone and only in spring. Ultimately, the tidal zone was slowly replaced by alternative foundation species, composed of different canopy-forming brown seaweeds that dominated different intertidal elevations, resulting in a net increase in canopy and understory diversity. This study is a rare example of long-term effects following an extreme MHW that caused extinctions of a locally dominant canopy-former, but these events and their associated dramatic changes to community structures and biodiversity are expected to become increasingly common as MHWs continue to increase in strength, frequency, and duration.

Skewed morph ratios lead to lower genetic diversity of the heterostylous Primula veris in fragmented grasslands.

Populations of heterostylous plant species are ideally composed of equal frequencies of two (distylous) or three (tristylous) morphologically different floral morphs. Intra-morph incompatibility helps to avoid inbreeding and to maintain genetic diversity, supporting plant fitness and long-term viability. Habitat fragmentation can lead to skewed morph ratios and thereby reduce the abundance of compatible mates. This, in turn, can result in a loss of genetic diversity. We tested whether the genetic diversity of heterostylous plants is affected by morph ratio bias using populations of the distylous grassland plant Primula veris in recently fragmented grasslands. We recorded morph frequencies and population sizes in 30 study populations of P. veris on two Estonian islands characterised by different degrees of habitat fragmentation. Examining variation of thousands of single nucleotide polymorphisms (SNPs) and heterostyly-specific genetic markers, we quantified overall and morph-specific genetic diversity and differentiation in these populations. Morph frequencies deviated more in smaller populations. Skewed morph ratios had a negative effect on the genetic diversity of P. veris in more fragmented grasslands. In the populations of better-connected grassland system, genetic differentiation among S-morphs was higher than among L-morphs. Our study shows that deviations from morph balance are stronger in small populations and have a negative impact on the genetic diversity of the distylous plant P. veris. Together with the direct negative effects of habitat loss and decreased population size on the genetic diversity of plants, morph ratio bias may intensify the process of genetic erosion, thus exacerbating the local extinction of heterostylous species.

New survey data on abundance and movements for two poorly known Asian Spiny Frogs

We present new natural history data on abundance and movements (daily and seasonal) during the pre-breeding (March-June) and breeding-post-breeding season (July-September) of two poorly studied frog species of the Himalayas, Nanorana vicina and Allopaa hazarensis. We estimated 185 Murree Hills Frogs and 90 Hazara Frogs within the study area (0.79 ha). The daily and seasonal movement data showed that the two species moved either between neighboring ponds or remained in an array of smaller ponds (within an area of 120 m2) along the stream bank. About 75% of movements were < 29.5 m in N. vicina and < 50.87 m in A. hazarensis during pre-breeding season while < 41.5 m in N. vicina and < 81 m in A. hazarensis during breeding-post-breeding season. We suggest inclusion of amphibian habitat requirements and ensuring stream connectivity in urban planning and development projects in the area to prevent the local extinction of the endemic species. In the future, more robust and long-term studies, encompassing more streams situated within a wider area, would help clarify dispersal, colonization, metapopulation structure, and dynamics of these endemic frogs of the forested montane streams in the Himalayan Foothills.

UAVs for monitoring responses of regenerating forests under increasing climate change-driven droughts - a review

The impact of climate change-driven droughts on regenerating forests is poorly understood due to the complexities involved in regeneration processes and the difficulties in measuring the relevant parameters with sufficient spatial and temporal resolution in a timely manner. Drought increases tree mortality in both undisturbed and disturbed forests and may influence forest regeneration dynamics from seed germination to the recruitment, growth, and survival of tree seedlings. Seedlings and small saplings may be more susceptible to changes in water availability than larger individuals due to their shallower roots that may be unable to reach the deeper, moist soil layers, and due to uneven competition with adult trees for soil moisture. The potential range shifts and local extinction of drought-sensitive species can also result in changes in forest species community composition and diversity loss at different scales. There is a need for precise and low-cost monitoring systems that facilitate better capturing of the complexities of such processes for restoration measures. The objective of this paper is to study the use of UAVs (Unmanned Aerial Vehicles) for monitoring responses of regenerating forests under increasing climate change-driven droughts. UAVs have several advantages over traditional field-based monitoring techniques and flexibility in selecting the required spatiotemporal resolution over other remote sensing methods, making them a promising tool for monitoring forest recovery. Although further research is required to ensure the accuracy and effectiveness of UAV-facilitated measures for monitoring forest regeneration, UAVs possess great potential in forest management in the event of increasing occurrences of climate-change driven droughts.