High Habitat Research Articles

Spatial-temporal changes of landscape and habitat quality in typical ecologically fragile areas of western China over the past 40 years: A case study of the Ningxia Hui Autonomous Region.

In this paper, we use the InVEST model and five periods of land use data from 1980 to 2020 to assess the habitat quality of the Ningxia Hui Autonomous Region in Western China, which has characteristics of a typical fragile ecosystem. We further analyse the spatial and temporal characteristics of habitat quality evolution and its relationship with land use and landscape pattern indices to explore the close relationship between regional habitat quality changes and human natural resource conservation and utilization. The research results show that the overall habitat quality of Ningxia Hui Autonomous Region was stable and at a moderate level (0.57-0.60) during the 40 years from 1980 to 2020; Habitat patches (2020) with low (24.89%), high (22.45%) and very high (29.81%) quality occupy a larger proportion of the area, followed by very low (13.31%) and moderate levels (9.54%). Over the past 40 years, there have been 275 sample sites in Ningxia where habitat quality has deteriorated, 1593 sample sites where the habitat quality has remained stable, and 184 sample sites where the habitat quality has increased. From 1980 to 2020, the Mean Patch Area of landscape types in Ningxia decreased by 25.9 hm2. The Patch Density increased by 0.06 /hm2. The Largest Patch Index decreased by 15.69%. The Edge Density increased by 2.5 m/hm2. The Contagion Index decreased by 2.99%. The Area-Weighted Mean Patch Fractal Dimension remained basically unchanged (0.01). The Landscape Shape Index showed a trend of first increasing and then decreasing, increasing by 13.94. The Area-Weighted Mean Shape Index has been reduced by 9.45. The Shannon Diversity Index and Shannon Evenness Index both show an increasing trend, but the amplitude is relatively small, with 0.09 and 0.04, respectively. There was a significant spatial aggregation of high and low habitat quality in Ningxia, with high values usually distributed in the northern and southern areas with good natural conditions and low values distributed in areas with frequent human activities and poor natural conditions. The decrease in habitat quality in Ningxia was mainly due to the expansion of cultivated land and construction land, the increase in landscape fragmentation and the resulting decrease in connectivity. On the other hand, due to the implementation of ecological protection measures, such as the project of returning farmland to pasture and grass to forest, the quality of habitats in Ningxia increased. The conclusions of this study support the idea that the conservation of habitat quality in ecologically fragile areas should fully preserve the original natural habitats and reduce the interference of human activities to increase the habitat suitability of the landscape and the habitat connectivity between patches. At the same time, targeted ecological protection policies should be developed to restore the areas where the habitat quality has been damaged and ultimately maintain the stability of biodiversity and ecosystems in ecologically fragile areas. Meanwhile, for ecologically fragile areas with similar ecological characteristics to those of Ningxia, our research supports the idea of increasing the protection of the stability of the original habitats, increasing the proportion of ecological restoration projects, financial investment and seeking cooperation with local community managers and residents will help to improve the quality of the regional habitats and the enrichment of the biodiversity, and ultimately promote the harmonious coexistence of human beings and nature in the modernized sense of the word.

Modelling habitat suitability for the Critically Endangered Manumea or Tooth-billed Pigeon Didunculus strigirostris using past and present baselines

Summary Evidence-based conservation can be hindered by limited field data, but historical archives have the potential to provide unique insights into conservation-relevant parameters, such as identification of suitable habitat for threatened species. The Manumea or Tooth-billed Pigeon Didunculus strigirostris has declined on Samoa and only a tiny remnant population still persists, and a key first step for conservation is to locate surviving birds. Numerous Manumea records are available from the nineteenth century onwards, and we used historical and modern records to generate a series of species distribution models to predict the distribution of suitable habitat across Samoa to guide new field searches. Manumea distribution is closely associated with forest cover or its proxies. Preferred Manumea food plants are suggested to be low-elevation trees, but elevation provides relatively low percentage contribution in most models, thus not excluding the possibility that Manumea might occur at high elevations. There is also little evidence for elevational change in records over the past century. Models based on visual versus acoustic records exhibit differences in predicted habitat suitability, suggesting that some purported acoustic records might not actually represent Manumea calls. Field searches should target areas representing high habitat suitability across all models, notably the forested central axis of Upolu.

High habitat richness reduces the risk of tick-borne encephalitis in Europe: A multi-scale study

BackgroundThe natural transmission cycle of tick-borne encephalitis (TBE) virus is enhanced by complex interactions between ticks and key hosts strongly connected to habitat characteristics. The diversity of wildlife host species and their relative abundance is known to affect transmission of tick-borne diseases. Therefore, in the current context of global biodiversity loss, we explored the relationship between habitat richness and the pattern of human TBE cases in Europe to assess biodiversity's role in disease risk mitigation. MethodsWe assessed human TBE case distribution across 879 European regions using official epidemiological data reported to The European Surveillance System (TESSy) between 2017 and 2021 from 15 countries. We explored the relationship between TBE presence and the habitat richness index (HRI1) by means of binomial regression. We validated our findings at local scale using data collected between 2017 and 2021 in 227 municipalities located in Trento and Belluno provinces, two known TBE foci in northern Italy. FindingsOur results showed a significant parabolic effect of HRI on the probability of presence of human TBE cases in the European regions included in our dataset, and a significant, negative effect of HRI on the local presence of TBE in northern Italy. At both spatial scales, TBE risk decreases in areas with higher values of HRI. InterpretationTo our knowledge, no efforts have yet been made to explore the relationship between biodiversity and TBE risk, probably due to the scarcity of high-resolution, large-scale data about the abundance or density of critical host species. Hence, in this study we considered habitat richness as proxy for vertebrate host diversity. The results suggest that in highly diverse habitats TBE risk decreases. Hence, biodiversity loss could enhance TBE risk for both humans and wildlife. This association is relevant to support the hypothesis that the maintenance of highly diverse ecosystems mitigates disease risk.

Unlocking Bevacizumab's Potential: rCBVmax as a Predictive Biomarker for Enhanced Survival in Glioblastoma IDH-Wildtype Patients.

Aberrant vascular architecture and angiogenesis are hallmarks of glioblastoma IDH-wildtype, suggesting that these tumors are suitable for antiangiogenic therapy. Bevacizumab was FDA-approved in 2009 following promising results in two clinical trials. However, its use for recurrent glioblastomas remains a subject of debate, as it does not universally improve patient survival. In this study, we aimed to analyze the influence of tumor vascularity on the benefit provided by BVZ and propose preoperative rCBVmax at the high angiogenic tumor habitat as a predictive biomarker to select patients who can benefit the most. Clinical and MRI data from 106 patients with glioblastoma IDH-wildtype have been analyzed. Thirty-nine of them received BVZ, and the remaining sixty-seven did not receive a second-line treatment. The ONCOhabitats method was used to automatically calculate rCBV. We found a median survival from progression of 305 days longer for patients with moderate vascular tumors who received BVZ than those who did not receive any second-line treatment. This contrasts with patients with high-vascular tumors who only presented a median survival of 173 days longer when receiving BVZ. Furthermore, better responses to BVZ were found for the moderate-vascular group with a higher proportion of patients alive at 6, 12, 18, and 24 months after progression. We propose rCBVmax as a potential biomarker to select patients who can benefit more from BVZ after tumor progression. In addition, we propose a threshold of 7.5 to stratify patients into moderate- and high-vascular groups to select the optimal second-line treatment.

Habitat suitability assessment for tule elk in the San Francisco Bay and Monterey Bay areas

While California’s statewide tule elk (Cervus canadensis nannodes) population has recovered from two or three individual survivors in the late 19th century, the subspecies exists today in numerous widely disjunct populations, leaving vast areas of the species’ former range uninhabited. Large unoccupied areas of historic tule elk range include the Santa Cruz Mountains and the northern Diablo and northern Santa Lucia ranges. Natural range expansion by existing populations into these areas is blocked by major highways and urban development; although, before considering tule elk translocations, it is necessary to assess the habitat suitability there. To this end, we fit a resource selection function (RSF) using generalized linear mixed models to GPS collar data collected from nearby radio collared tule elk and used several environmental GIS layers to capture important habitat characteristics. We fit the RSF in a habitat use versus availability framework with only linear and quadratic terms and used stepwise model selection ranked by AICc to maximize its generalizability, enabling transferability to our unoccupied study area. We also used k-fold cross validation to evaluate our RSF and found it predicted habitat within the San Luis Reservoir herd well. The fit habitat relationships mostly followed expectations based on tule elk ecology, including positive responses to herbaceous vegetation cover and waterbody proximity, and negative responses to high tree cover and high puma habitat suitability. Our RSF accurately predicted currently occupied elk habitat as suitable and found well over 500,000 ha (2,000 mi2) of suitable but unoccupied habitat throughout the northern Diablo Range, the inland and coastal sides of the Santa Cruz Mountains, and the northern Santa Lucia Range. Assuming translocations, and construction and improvement of highway wildlife crossings, our results support the potential for re-establishing tule elk in these regions, which are more coastal and mesic than the species’ current habitat in the central Diablo and northern Gabilan ranges.

Exploring watershed ecological risk bundles based on ecosystem services: A case study of Shanxi Province, China

Humans are having an increasingly profound impact on the environment along with the advent of the Anthropocene. Ecological risk assessment (ERA) as a method to quantify ecological problems can provide support for decision-makers, and it is one of key issues to integrate ecosystem services into ERA. In this study, an ERA framework was proposed under the loss-probability paradigm from the perspective of ecosystem services risk bundles. The results showed that initiatives aimed at ecological protection in Shanxi Province had been effective, the number of watersheds with low-risk bundles increased significantly (from 16.09% to 34.49%) and the watersheds basically overlapped with key forestation areas. However, the effects of forestation activities may no longer be as significant as they once were, as the relationship between forestation and water supply was becoming increasingly contradictory. Meanwhile, the conflict between urban expansion and natural ecosystem protection was intensifying, habitat degradation risks were gradually polarized, and the risk bundles dominated by high carbon emission and habitat degradation were increasing significantly (from 15.88% to 33.54%). Strengthening the construction of urban green space and controlling the expansion of human activities may be the next focus of ecological conservation in Shanxi Province. This study enriched the ERA framework with an ecosystem services risk bundle approach.

Invertebrate community composition differs between restored and natural vernal pools

The loss of freshwater wetlands worldwide has underscored the importance of restoration to enhance biodiversity and functional objectives. While aquatic invertebrate communities within restored perennial freshwaters are well studied, few studies have occurred in the greatly reduced habitat of seasonal wetlands, such as vernal pools. California vernal pools have experienced high habitat loss and support many threatened or endangered invertebrate species. We compared 90 natural and 90 restored vernal pools of different ages across 10 sites throughout California and Southern Oregon using the Sars' method. Large branchiopod abundance, total invertebrate abundance, class richness, and community composition were assessed between pool types (natural vs. restored) and along environmental gradients (e.g. site, pool depth, surface area, age since restoration). Large branchiopod and total invertebrate abundance were 215 and 274% higher in natural pools than restored pools, but class richness was not different. Community composition was significantly different and driven by greater abundances of vernal pool fairy shrimp, San Diego fairy shrimp, Ostracoda, Cladocera, and Copepoda in natural pools. Few environmental or habitat variables explained patterns in richness or abundance. Our work demonstrates that restored pools, even those decades old, are different than natural pools. Future mitigation and monitoring guidelines for restored vernal pools should include quantitative evaluations for aquatic invertebrates. Restored pools are not adequate compensation for lost natural pools because they do not have the same ecological functions and values.

Spatiotemporal variation of habitat quality and its response to fractional vegetation cover change and human disturbance in the Loess Plateau

It is of great practical significance to regional ecological conservation and restoration to explore the spatiotemporal variation characteristics of habitat quality in the ecologically fragile Loess Plateau. This study firstly explored the habitat quality in the Loess Plateau during 2000-2020 with the Integrated Valuation of Ecosystem Services and Trade-offs model. Then this study revealed the response characteristics of habitat quality to the fractional vegetation cover (FVC) change and human disturbance with the geographically weighted regression (GWR) model. Results showed habitat quality tended to improve in 51.16% of the study area, and area of high or very high habitat quality increased by 1.78%. Besides, FVC showed dominantly significant increase (62.42%) and high stability (69.66%) in the study area, and human disturbance increased remarkably in 18.11% of the study area but maintained the same level in 91.83% of the study area. Additionally, areas with positive correlation between habitat quality change and FVC and between habitat quality change and human disturbance change accounted for 52.56% and 37.38% of the study area, respectively, indicating FVC played dominant role in affecting the regional habitat quality variation. This study can provide important decision support information for the future ecological conservation of the Loess Plateau.

Study of spatiotemporal variation and driving factors of habitat quality in the northern foothills of the Qinling Mountains: a case study of Xi’an, China

As earth surface human activities become more frequent, global ecosystem service functions and especially biodiversity maintenance functions are challenged. This study aimed to analyze spatiotemporal changes in Xi‘an section of the northern foothills of the Qinling Mountains from 1990 to 2020. Temporal and spatial changes in habitat quality in the study area were visualized using InVEST model and land use data, and factors affecting habitat quality were analyzed using Geodetector. The results showed that during the study period, the cultivated land, grassland, and water decreased by 16.40%, 74.37%, and 35.39%, respectively, while the area of forest land and construction land increased, among which the construction land increased by 117.70%, the largest increase, and the forest land increased by 8.47%. The main changes in land use are the conversion of cultivated land into forest land and construction land, and the conversion of grassland into forest land and cultivated land. During the period 1990–2020, the average habitat quality index in the study area changed from 0.8617 to 0.8585, showing a slow decreasing trend. The spatial distribution of habitat quality showed a trend of “high in the south, moderate in the north, and low in the northwest”. The high habitat quality was mainly concentrated in the southern forest land, the middle habitat quality was mainly distributed in the northern cultivated land, and the low habitat quality was mainly distributed in the northwest construction land. The land use type has a great influence on habitat quality, and the interaction between any two factors is stronger than that of a single factor. The temporal and spatial variation of habitat quality is influenced by both natural and human factors. This study provides a theoretical basis for ecological protection and nature reserve planning in the Qinling Mountains region.

Time will tell: Taxonomic and functional diversity of monilophyte ferns in native forests and abandoned silviculture systems

AbstractDifferent forest systems can influence the function, traits, diversity, and distribution of ferns. By comparing ferns based on their functional traits, we can explore how species loss affects functional diversity, and consequently alter the forest ecosystem. We investigated the impact of abandoned silviculture on fern diversity (taxonomic and functional) and abundance. Our hypothesis suggests a positive effect of nutrients and soil humidity in native forests, while canopy openness in silviculture has a negative effect on monilophyte diversity. This study was conducted in three sites of native forest and three sites of Pinus silviculture. Each site was subdivided into three areas, with three plots per area, resulting in 54 plots (3 sites × 3 areas × 3 plots × 2 forest types). Each plot covered an area of 100 m2 (10 m × 10 m; 5400 m2 in total). In each plot, we estimated abundance, functional attributes (richness, evenness, divergence, and dispersion) based on leaf thickness, leaf width, petiole length, stem length, leaf division, sori shape, indusium presence, and taxonomic diversity. Results indicate that native forest exhibit higher taxonomic and functional diversity (richness—Fric) compared to abandoned Pinus plantations, which may be attributed to high habitat diversity and species specialization in specific microhabitats. In silviculture, diversity homogenization leads to an increase in the redundancy of functional attributes (evenness—Feve), resulting in the filtering out of similar organisms. Abiotic factors such as light and canopy openness negatively influence plant establishment and growth, leading to a decrease in leaf division and indusium presence/absence (by CWMs), supporting niche complementarity theory in natural forest and mass ratio theory in silviculture. Our findings highlight the enduring negative impact of silviculture, even after 20 years, on both the taxonomic and functional diversity of monilophytes, underscoring the crucial role of native forests in preserving fern diversity.

Dynamic simulation of land use change and habitat quality assessment under climate change scenarios in Nanchang, China.

Investigating habitat quality under different climate scenarios holds significant importance for sustainable land resource management and ecological conservation. In this study, considering Nanchang as a case study, a coupled patch-generating land use simulation (PLUS) and system dynamics (SD) model was employed in the simulation and prediction of land usage under shared socioeconomic pathway (SSP) and representative concentration pathway (RCP) scenarios. To assess the habitat quality in Nanchang from 2000 to 2020 and in 2030 under three diverse climate scenarios, we used the Integrated Valuation of Ecosystem Services and Trade-offs (InVEST) model to analyze spatial and temporal changes. The findings indicate that the regions of forest land, cultivated land, and grassland in Nanchang City will dramatically decrease by 2030, the construction land will rapidly expand, and the fluctuations in the unutilized land and water area will be minimal. Additionally, the habitat quality declined from 2000 to 2020, and its spatial distributions changed. Zones having a high overall habitat quality were distributed in the mountains, hills, and lake areas, whereas those with relatively low quality were found in cultivated and urban areas. Under three climate scenarios, in 2030, the habitat quality index for Nanchang City will show a decreasing trend, mainly owing to areas with an index of 0.3-0.5 transitioning to <0.3. Considering each scenario, the degree of habitat degradation increased in the order SSP585>SSP245>SSP119. The findings of this study will inform high-quality development and biodiversity conservation in Nanchang City.

Predicting invasive species distributions using incremental ensemble-based pseudo-labeling

Control strategies for preventing the spread of invasive species require their accurate geographical distribution. Species distribution models (SDMs) that can predict potential habitats of invasive species and thereby derive habitat suitability maps have become a valuable tool for supporting regulatory strategies. To date, machine learning (ML)-based approaches have outperformed profile and statistical-based approaches in terms of species distribution prediction accuracy. However, ML-based approaches often suffer from poor predictive performance when there is insufficient labeled data. Recently, pseudo-labeling (PL), a semi-supervised learning method, has been proposed to alleviate this problem, but pseudo-labels generated using a single-teacher model with very few labeled data points are generally biased and not suitable for training SDMs. In this paper, we propose a novel prediction scheme for invasive species distributions using incremental ensemble-based PL (SDP-EPL). We first build an ensemble-based teacher using multiple conventional SDMs and then incrementally construct a training set, starting with very few labeled data points, by repeating the following process: (i) generating pseudo-labels for unlabeled data using the teacher model, (ii) appending the pseudo-labeled data representing high or low habitat suitability to the training set, and (iii) training the teacher model using the updated training set. We then train a student SDM using the training set. Based on extensive experiments using citizen science datasets for three species, we show that the proposed scheme outperforms other commonly used SDMs in terms of diverse evaluation metrics and achieves performance improvements of up to 14.61% and 5.45% compared to the baseline and state-of-the-art models, respectively. We also demonstrate the effectiveness of the ensemble teacher model and incremental labeling in terms of predictive accuracy.

Preliminary study on the man-made habitat of Utricularia gibba L. in the tropical peatland environment

Utricularia gibba L. is a free-floating aquatic carnivorous plant found in some parts of the world, including Asian tropical regions. However, data on water’s physical and chemical properties for the ecology of this species in Asian tropical peatland environments are underrepresented in the literature. Here, we reported water physical and chemical properties for the habitat of U. gibba occurring in the tropical peatland of Kalimantan Barat, Indonesia. The study site is on the man-made water canal in Jalan Parit Haji Muksin II, Kubu Raya Regency, Kalimantan Barat. We measured temperature, electrical conductivity (EC), Total Dissolved Solid (TDS), pH, Dissolved Oxygen (DO), total nitrogen, total phosphorus, nitrates, and nitrite of the waters at three points along the water canal where the bladderworts occur. The results showed that U. gibba inhabits waters with low conductivity (< 66 µS cm-1), low TDS (< 32 ppm), acidic (< pH 6), low DO (< 8 mg L-1), but higher total nitrogen (7.02 – 19.4 mg L-1), total phosphorus (0.86 – 1.71 mg L-1), nitrates (3.01 – 4.06 mg L-1) and nitrite (3.53 – 5.18 mg L-1). These findings demonstrate that U. gibba in tropical peatland environments reportedly occurs in acidic (pH 5.03 – 5.29) but relatively high nutrient habitats compared to its counterpart and other species found elsewhere.

Changes of the composition of the Noctuoidea fauna along a geographical gradient in the northeastern part of the Carpathian Lowland

The northeastern part of the Carpathian Lowland is one of the most species-rich parts of the region, despite the long-term and sometimes extreme changes in land use. The fragmented remains of formerly contiguous forests maintain a significant part of the wildlife living in different oak, mixed oak, and gallery forest, and even faunas of connected grassland habitats. To reveal how the parallel Carpathian and Pannonian effects form the local insect fauna, the Noctuoidea assemblages of eight forest patches were assessed and compared, based on the distribution data of 479 species. Three types of assemblages were designated, with similar diversity but different compositions. The most unique and valuable ones can be found in the colline area of Transcarpathia, where the high habitat diversity supported by the topography promotes the coexistence of the species of humid forest fauna and many steppic and southern elements. The protection and planned management of these remained forest patches and their network in international cooperation can maintain a significant part of the fauna of the affected regions.

Habitat Quality Assessment and Driving Factor Analysis of Xiangyu in Feng River Basin Based on InVEST Model

Analyzing the evolution of regional habitat quality is an important means to assess the impact of engineering activities on ecosystems. Taking Xiangyu in the Feng River Basin as the study area, the land use change in 1985 and 2022 was analyzed, and the habitat quality and degradation degree were evaluated by using the Integrated Assessment and Tradeoff of Ecosystem Services (InVEST) model. The results showed that from 1985 to 2022, the transfer of land use types in Xiangyu mainly occurred on dry land, bare land, forest land, and industrial land. The area of dry land and bare land converted into industrial land is 10,825.15 m2 and 249,123.09 m2, respectively, and affected by the measures of returning farmland to forest and grassland in Shaanxi Province, the area transferred to forest land reached 371,471.87 m2, mainly from dry land and bare land. The continuous expansion of industrial land led to a significant decline in habitat quality, and the areas with high habitat degradation were concentrated in forest land in a large range, which indicated that forest land was vulnerable to industrial land expansion. Land use change and human engineering activities are the main factors affecting the ecological environment, and limiting the expansion rate of industrial land is the key to protecting the ecological environment.

Multiscale spatial patterns and environmental drivers of seamount and island slope megafaunal assemblages along the Mozambique channel

Seamounts are vulnerable ecosystems targeted by fishing and potentially by future mineral exploitation. Their abundance, widespread distribution, and heterogeneity of faunal and abiotic components require integrated studies at multiscale to describe spatial patterns and identify environmental drivers needed by conservation plans. There is also a lack of knowledge on seamount benthic ecosystems in some regions, such as the Indian Ocean. These gaps, in the context of Marine Protected Areas establishment in the region, have motivated the present study focusing on the Mozambique Channel Eparses islands and flat top seamounts, along a 10-degree latitude gradient. These structures are characterized by complex volcanic and carbonate geomorphologies at multiscale and are distributed along a highly dynamic turbulent ocean circulation area with large anticyclonic eddies. For the first time, we analysed, from seabed image transects obtained by towed-camera on four seamounts, and two volcanic islands - Bassas da India and Mayotte - external slopes, and from multiscale environmental data, how benthic communities respond to this high habitat heterogeneity at regional, and local scales. This study reveals high discrepancies of benthic megafauna richness, density, and beta diversity among seamounts and among slopes of the same islands. Moreover, at similar latitude, seamounts display higher densities than island slopes. The highest densities found on a seamount of the Glorieuses archipelago are explained by strong currents and flat homogeneous geomorphology. Except on this seamount, the beta diversity is high, despite the quite limited depth range explored (84–734 m) and is the highest on island slopes and Hall Bank, driven by the diversity and hardness of the substrate. Beta diversity is mainly due to taxa turnover, with high contribution of the habitat-forming sponges and cnidarians, together with a few mobile taxa. We identified from biogeographic network analysis 12 dominant faunal assemblages, displaying a patchy distribution, with variability in composition both among and within sites. Currents and primary productivity explain ∼15% of the observed assemblage structure along the channel, while geomorphology (km scale), topography (60–500 m scale) and substrate (60-m units) explain together 24% of the faunal spatial patterns. Analysis of spatial structures along island slopes detected some small (100–200 m), medium (∼1 km) and large scale (∼2–6 km) megabenthic community structures, partly explained by topography, substrate, depth, and slope. Despite limited taxonomic identifications for this poorly sampled area, this study reveals an outstanding heterogeneity of megabenthic assemblages at multispatial scales in the Mozambique Channel seamounts and island slopes, in response to the complex hydrography and geology of the area. Further characterization of environmental drivers with greater focus at local scales including hydrographic variables are therefore needed to improve predictions of suitable habitats of vulnerable marine ecosystems.

Floristic, chorological and life-form patterns at the highest summits of Mt Olympus, Greece

ABSTRACT High elevation habitats within the Mediterranean biome are expected to be disproportionally exposed to climate change impacts in comparison to the ecosystems of the lower and drier sites. The distribution and structure of alpine ecosystems greatly depend on temperature variables including growing season length. Tree-line shifts, structural change of alpine plant communities and shifts of the alpine-nival ecotone are among the most commonly observed impacts of climate change. The Global Observation Research Initiative in Alpine Environments (GLORIA) network has developed a common methodology and facilitates a global approach for studying the effects of climate change in alpine ecosystems with repeated measurements in permanent plots. Mt Olympus, Greece, was the last target region to join the network. In this study we use the vegetation data from the baseline survey on Mt Olympus to describe floristic patterns along an elevational gradient of four summits. To examine compositional, life-form and chorological differences between- and within-summits we analyzed data from 32 plots. Moreover, we fitted generalized linear models to distinguish important environmental variables for the occurrence of plant taxa. Our results demonstrate that elevation was the dominant factor influencing vegetation changes along the examined gradients. Additional, the life-form spectrum does not provide sufficient information to be used as index for monitoring climate change impacts on vegetation composition. Instead, the use of the species matrix provides enough information regarding the between-summits dissimilarities. We also identified a number of plant taxa that are highly related to either low or high elevations. These taxa could be used as early warning indices of compositional shifts.

Potential distribution and conservation of the hog-nosed skunk (genus Conepatus, Mammalia: Mephitidae)

Understanding the range-wide distribution and abundance of species is critical for their conservation and management. Hog-nosed skunks, genus Conepatus, are an understudied small carnivores’ taxa with a broad geographic range across America. However, the factors that shape their distribution are poorly understood and large-scale analyses of Conepatus species’ range and ecological niche are absent. On the basis of species occurrence records, large-scale environmental variables (bioclimatic and topographic) and using niche-based species distribution modeling, we estimate the suitable areas and the most important variables that underlie their distribution. Although general pattern of Conepatus distribution is mostly congruent with those described from the literature, C. semistriatus seems to be expanding they distribution range, likely at the expense of changes in anthropogenic land use. Our results show that isothermally (for C. chinga and C. leuconotus) and the mean of the monthly temperature ranges (for C. semistriatus) are the main variables influencing hog-nosed skunks’ distribution. Also, the three species responded negatively to the presence of trees. Finally, and according to our models, sites of high habitat suitability, at least for C. chinga, are underrepresented in protected areas. We believe that the geographic and potential distribution maps presented here constitutes a valuable tool to better understand Conepatus ecology as well as for their conservation planning.

Biogeographic patterns of micro-eukaryotic generalists and specialists and their effects on regional α-diversity at inter-oceanic scale

Inter-oceanic scale studies allow us to understand the global spread of micro-organisms in marine ecosystems. In this study, micro-eukaryotic communities in marine surface sediment were collected from tropical to Arctic sites. We found that micro-eukaryotic generalists had much higher intraspecific variation than specialists which allow them to distribute more widely through higher spatiotemporal asynchrony and complementary niche preferences among conspecific taxa. Moreover, comparing to the host-associated protozoa and small metazoa, the algae and free-living protozoa with higher intraspecific variation allow them to have wider distribution ranges. Species abundance also played an important role in driving the distribution ranges of generalists and specialists. The generalists had important effects on regional α-diversity even at an inter-oceanic scale which led to the micro-eukaryotic species richness in polar sites to be mainly influenced by the regional generalists but not the local specialists. In particular, more than 97% of algal species in polar sites were shared with the tropical and subtropical sites (including toxic dinoflagellate). Overall, our study suggests that the effects of global change and human activities on the vulnerable high latitude habitats may lead to biotic homogenization for the whole microbial community (not only the dispersal of some harmful algae) through the potential long-distance spread of generalists.

Construction of multi-level ecological security network in fragmented nature landscape using the three-dimensional framework of ecological adaptability

As the basis for constructing ecological security network, the ecological source has been broadly understood as larger patches that provide important ecosystem services and high comprehensive habitat quality. But the traditional methods for identifying ecological source (e.g. selecting natural vegetation patches and connectivity analysis) are not suitable for the Yanhe River Basin due to its fragmented patches and high vegetation cover. With the progress of research, the multidimensional evaluation framework is used to extract ecological source to mine more function and characteristic of ecosystem. Considering the fragmented nature of patches and the rapid recovery characteristics of vegetation in the Yanhe River Basin, a comprehensive evaluation model was developed based on the three-dimensional framework of ecological adaptability cycle (potential-resilience-connectivity) to extract ecological source. Additionally, due to the insufficient size of the extracted ecological source area to meet the increasing demand for ecosystem services in the future, the potential patches with high ecosystem services and large distribution were considered as secondary ecological source, and the patches with weak connectivity but high potential resilience were as considered tertiary ecological source. Finally, the ecological corridors were delineated based on the three ecological sources and the selected ecological resistance surface. The primary ecological sources were predominantly located in the central region, where grassland was the dominant land use type. The secondary ecological sources were mainly distributed in the southern woodland belt with the highest ecological services, but further enhancements to these services were unattainable. The tertiary ecological sources were mainly distributed in the western region and represented high-quality potential targets for future ecological source expansion. Therefore, it is recommended to give priority to the construction of a primary ecological corridors. The secondary ecological corridors exhibit the lowest comprehensive resistance, and can be constructed concurrently with the primary ecological corridors. Given its highest total comprehensive resistance, construction of tertiary ecological corridors should be contingent upon economic feasibility.