Remote sensing variables improve species distribution models for alpine plant species

Species distribution models (SDMs) are cost-effective, transparent and flexible planning tools to support various areas in nature conservation. Variables taken from remote sensing (RS) are broadly applicable to biodiversity studies. In our study, we combined RS-variables (normalized differenced vegetation index and land surface temperatures), with topographic and geological variables to produce detailed SDMs in the context of a seed collection campaign of the Alpine Seed Conservation and Research Project. To identify effective predictor variable combinations we compiled three different variable sets and compared the predictive model performance.The full model, that combines all types of variables, slightly outperforms (average values for TSS: 0.91, AUC: 0.98, Kappa: 0.7) models that use topo-climatic variables (average values for TSS: 0.91, AUC: 0.98, Kappa: 0.68) or NDVI (average values for TSS: 0.85, AUC: 0.96, Kappa: 0.54) alone. We also produced ensemble models that performed slightly better compared to the different model algorithms used in our approach. We identified the temperature of the coldest month, mean NDVI and bedrock as important variables that determine the distribution of alpine plant species.Our full models show high accordance with actual species distribution ranges and are highly relevant for efforts to identify special areas for either in-situ or ex-situ conservation.     

Remote sensing of biodiversity: what to measure and monitor from space to species?

Global biodiversity monitoring systems through remote sensing can support consistent assessment, monitoring, modelling and reporting on biodiversity which are key activities intended for sustainable management. This work presents an overview of biodiversity monitoring components, i.e. biodiversity levels, essential biodiversity variables, biodiversity indicators, scale, biodiversity inventory, biodiversity models, habitat, ecosystem services, vegetation health and biogeochemical heterogeneity and discusses what remote sensing through Earth Observations has contributed to the study of biodiversity. The technological advancements in remote sensing have enabled information-rich data on biodiversity. Remote sensing data are making a strong contribution in providing unique information relevant to various biodiversity research and conservation applications. The extensive use of Earth observation data are not yet realized in biodiversity assessment, monitoring and conservation. The development of direct remote sensing approaches and the techniques for quantifying biodiversity at the community to species level is likely to be a great challenge for comprehensive earth observation-based monitoring strategy.

     

Exploring the spatiotemporal dynamics of habitat suitability to improve conservation management of a vulnerable plant species

Ongoing declines in biodiversity caused by global environmental changes call for adaptive conservation management, including the assessment of habitat suitability spatiotemporal dynamics potentially affecting species persistence. Remote sensing (RS) provides a wide-range of satellite-based environmental variables that can be fed into species distribution models (SDMs) to investigate species-environment relations and forecast responses to change. We address the spatiotemporal dynamics of species’ habitat suitability at the landscape level by combining multi-temporal RS data with SDMs for analysing inter-annual habitat suitability dynamics. We implemented this framework with a vulnerable plant species (Veronica micrantha), by combining SDMs with a time-series of RS-based metrics of vegetation functioning related to primary productivity, seasonality, phenology and actual evapotranspiration. Besides RS variables, predictors related to landscape structure, soils and wildfires were ranked and combined through multi-model inference (MMI). To assess recent dynamics, a habitat suitability time-series was generated through model hindcasting. MMI highlighted the strong predictive ability of RS variables related to primary productivity and water availability for explaining the test-species distribution, along with soil, wildfire regime and landscape composition. The habitat suitability time-series revealed the effects of short-term land cover changes and inter-annual variability in climatic conditions. Multi-temporal SDMs further improved predictions, benefiting from RS time-series. Overall, results emphasize the integration of landscape attributes related to function, composition and spatial configuration for improving the explanation of ecological patterns. Moreover, coupling SDMs with RS functional metrics may provide early-warnings of future environmental changes potentially impacting habitat suitability. Applications discussed include the improvement of biodiversity monitoring and conservation strategies.     

Conservation of Portuguese red-listed bryophytes species in Portugal: Promoting a shift in perspective on climate changes

Knowledge of bryophyte diversity can be an important tool for identifying overall biodiversity hotspots. The distribution of red-listed species is an essential data for biodiversity conservation actions, and the assessment of species' response to climate change scenarios is also a key tool in future conservation strategies. In this study, we examine the response of four phytogeographic assemblages of all Portuguese red-listed bryophytes whose distributions are well documented in Portugal. The red-listed species were selected based on their vulnerability as listed in the new Atlas and Red Data book of Portuguese bryophytes according to the IUCN criteria. The main purpose of this study is to develop predictive distributions of threatened bryophytes grouped according to phytogeographic trends aiming to conserve this bryoflora in future. This is achieved by the identification of relationships between specimens' distributions and environmental ecologically meaningful data, which is known to influence different phytogeographic assemblages. Significant differences were found in all distribution models based on future climate scenarios. Several variables play a vital role in the species' distribution models in present and future environmental conditions.     

Fungal diversity on decaying beech logs – implications for sustainable forestry

An analysis of factors influencing the diversity of macrofungi fruiting on decaying beech logs at site level is presented. Variables related to log size and shape and decay stage were found to explain up to 56% of the variation in total species richness and 42% of the variation in the richness of threatened (red-listed) species. Inclusion of variables relating to the vernal flora and the degree of soil contact further increased the explained variation in total species richness to 71%, but these variables were non-significant with respect to red-listed species. However, inclusion of the variable log type, distinguishing uprooted logs, logs broken at root neck and logs broken 1–7 and 8–15 m above ground, increased the amount of explained variation in richness of red-listed species to 50%. Among the log size and shape variables, the number of bole forks was superior in describing the variation in both total and red-listed species richness. Accordingly, forked trees should preferably be selected for decay in order to improve biodiversity, since they support comparably higher species diversity than unforked logs and have limited economical value. The importance of log type for the richness of threatened species appears to be connected with the occurrence of certain non-dominant primary decayers, causing heart rot, subsequently allowing the establishment of red-listed species. Accordingly, it is suggested that a high diversity of primary decayers may be a key to the conservation of wood decaying fungi. Microclimatic variables were found to have a limited effect on fruit body diversity on the studied logs; however, the microclimatic regime is discussed as an important factor in relation to management of dead wood for fungal biodiversity.     

Spatially modelling native vegetation condition

Summary   The assessment of vegetation condition is seen as an increasingly important requirement for effective biodiversity conservation in Australia. Condition assessments that operate at the scale of the site are well established. However, there is a need for mapped representations of vegetation condition at regional scales to: (i) assist with regional planning and target setting; (ii) provide regional context for site-based assessment; and (iii) monitor the change in vegetation condition at multiple scales. This paper describes a methodology for converting site condition data collected in plots into maps of vegetation condition across entire regions using a predictive statistical modelling framework (Generalized Additive Modelling) combined with a GIS. The research demonstrates how explanatory variables including topographic position, terrain roughness, landscape connectivity and remote sensing derived indices can be used to map the condition of native vegetation at the scale of a subcatchment. The inclusion of indices derived from remotely sensed imagery (SPOT4) as explanatory variables in the modelling is a novel component of this research. Although the methodology generates statistically and ecologically plausible models of vegetation condition, there are nevertheless limitations associated with the way plot data were collected and some of the explanatory variables, which impacts upon model utility. We discuss how these problems can be minimized when embarking upon studies of this type. We demonstrate how maps produced from exercises such as this could be used for conservation planning and discuss the limitations of these data for monitoring.     

Inclusion of explicit measures of geodiversity improve biodiversity models in a boreal landscape

Measures of geodiversity may provide a potentially useful surrogate for biodiversity patterns in insufficiently surveyed areas. However, their reliability in modelling the spatial variation in species richness is inadequately understood. We investigated whether the explanatory and predictive power of species richness models can be improved by considering explicit measures of geodiversity (variability of earth surface materials, forms and processes) in addition to climate and topography variables. Vascular plant species richness was modelled in two study areas in Northern Europe, Finland at the resolution of 500 or 1000?m, and as a function of three geodiversity (geological, geomorphological and hydrological diversity) variables, and six climate and topography variables. Variation partitioning was used to identify the independent and shared contributions of the geodiversity, climate and topography variable groups in explaining the spatial patterns of species richness. Generalized additive models were used to explore the ability of the different explanatory variables in predicting plant species richness within and between the study areas. In both the study areas, the inclusion of measures of geodiversity improved the explanatory power, predictive ability and robustness of the plant species richness models. In conclusion, the explicit measures of geodiversity appear to be promising surrogates of biodiversity, which reflect important abiotic resource factors, and may thus provide an equally, or even more reliable basis for transferring biodiversity models to new areas than models based on climate and topography variables.     

Threat spots and environmental determinants of red-listed plant,butterfly and bird species in boreal agricultural environments

The aims of this study were (1) to examine the geographic distribution of red-listed species of agricultural environments and identify their national threat spots (areas with high diversity of threatened species) in Finland and (2) to determine the main environmental variables related to the richness and occurrence patterns of red-listed species. Atlas data of 21 plant, 17 butterfly and 11 bird species recorded using 10 km grid squares were employed in the study. Generalized additive models (GAMs) were constructed separately for species richness and occurrence of individual species of the three species groups using climate and land cover predictor variables. The predictive accuracy of models, as measured using correlation between the observed and predicted values and AUC statistics, was generally good. Temperature-related variables were the most important determinants of species richness and occurrence of all three taxa. In addition, land cover variables had a strong effect on the distribution of species. Plants and butterflies were positively related to the cover of grasslands and birds to small-scale agricultural mosaic as well as to arable land. Spatial coincidence of threat spots of plants, butterflies and birds was limited, which emphasizes the importance of considering the potentially contrasting environmental requirements of different taxa in conservation planning. Further, it is obvious that the maintenance of various non-crop habitats and heterogeneous agricultural landscapes has an essential role in the preservation of red-listed species of boreal rural environments.     

Relative importance of habitat area, connectivity, management and local factors for vascular plants: spring ephemerals in boreal semi-natural grasslands

Using species and environmental data from an extensive grassland area in south-western Finland, we investigated the effect of patch area and connectivity, management and local habitat variables on the occurrence of spring-flowering vascular plants and their richness in boreal agricultural landscapes. Generalized linear models (GLM) and variation partitioning were used to study the explanatory power of the three groups of variables and their combined contributions on the richness and occurrence of six spring-flowering plant species. Generalized additive models (GAMs) and associated cross-validation tests were used to evaluate the predictability of the species occurrence and richness patterns. Present-day grassland patch area and connectivity were important predictors for occurrence and richness of the studied plant species. In addition, local habitat factors, especially radiation, accounted for major fractions of occurrence patterns of the studied species. Hybrid models including variables from all three variable groups had higher explanatory power and predictive capability than partial models. However, performance of the separate single-species models varied considerably between the six study species. Exclusion of radiation or connectivity from the hybrid models decreased their predictive performance, suggesting that these factors are of particular importance for grassland plant species at their northern range margins. When developing conservation and management planning for grassland plant species in Northern Europe, attention should be paid to well-connected networks of grassland patches including large, steeply-sloped patches with a favorable microclimate.     

Relative importance of hydrological variables in predicting the habitat suitability of Euryale ferox Salisb.

Aims Aquatic ecosystems are a priority for conservation as they have become rapidly degraded with land-use changes. Predicting the habitat range of an endangered species provides crucial information for biodiversity conservation in such rapidly changing environments. However, the complex network structure of aquatic ecosystems restricts spatial prediction variables and has hitherto limited the use of habitat models to predict species occurrence in aquatic ecosystems. We used the maximum entropy model to evaluate the potential distribution of an endangered aquatic species, Euryale ferox Salisb. We tested the relative influence of (i) climatic variables, (ii) topographic variables, and (iii) hydrological variables derived from remote sensing data to improve the prediction of occurrence of aquatic plant species.Methods We considered the southern part of the Korean Peninsula as the modeling extent for the potential distribution of E. ferox. Occurrence records for E. ferox were collected from the literature and field surveys. We applied maximum entropy modeling using remotely sensed environmental variables and evaluated their relative importance as prediction variables with variation partitioning.Important findings The species distribution model predicted potential habitats of E. ferox that matched the actual distribution well. Floodplain wetlands and shallow reservoirs were the favored habitats of E. ferox. Quantitative loss and fragmentation of wetland habitats appeared to be a major reason for the decrease of E. ferox populations. Our results also imply that hydrological variables (i.e. normalized difference water index) derived from remote sensing data greatly increased model prediction (relative contribution: 10.5–37.0%) in the aquatic ecosystem. However, interspecific competition within a similar niche environment should be considered to increase the accuracy of the distribution model.     

Past and present disturbances influence biodiversity value of subtropical grassland ecological networks

The effect of transforming natural habitat to commercial land uses can be mitigated by implementing ecological networks (ENs) in production landscapes. However, EN ability to conserve biodiversity is potentially influenced by past and present disturbances, and spatial configuration of habitat patches. Here, we investigated how plant assemblages of a subtropical EN in a timber production landscape in South Africa respond to disturbance history (i.e. natural vs. recovering after removal of Pinus spp.), mowing in firebreaks (i.e. 30 m wide grassy strips intended to stop spread of fires in plantations), and three design parameters: corridor width, distance to protected area boundary, and context i.e. proportion eucalypt compartments within 500 m radius. Reference sites were in the adjacent iSimangaliso Wetland Park, a protected area (PA). Past disturbances and the current practice of mowing in firebreaks significantly influenced plant species composition, but not plant species richness. Plant dominance was greatest in mowed firebreaks, but similar between natural and recovering grassland. None of the design variables affected plant species richness, or composition. However, dominance was significantly and negatively correlated with corridor width, and positively correlated with context. Hence, sites are ordered in terms of their biodiversity value from greatest to lowest: natural areas > recovering areas > firebreaks. Based on these results, natural grassland in wide, well-connected corridors should have greatest conservation priority. We recommend that past disturbances, and current management practices should be taken into account and integrated into the design of future ENs. Such an approach is necessary for effective biodiversity conservation in production landscapes.     

Supporting conservation with biodiversity research in sub-Saharan Africa’s human-modified landscapes

Protected areas (PAs) cover 12 % of terrestrial sub-Saharan Africa. However, given the inherent inadequacies of these PAs to cater for all species in conjunction with the effects of climate change and human pressures on PAs, the future of biodiversity depends heavily on the 88 % of land that is unprotected. The study of biodiversity patterns and the processes that maintain them in human-modified landscapes can provide a valuable evidence base to support science-based policy-making that seeks to make land outside of PAs as amenable as possible for biodiversity persistence. We discuss the literature on biodiversity in sub-Saharan Africa’s human-modified landscapes as it relates to four broad ecosystem categorizations (i.e. rangelands, tropical forest, the Cape Floristic Region, and the urban and rural built environment) within which we expect similar patterns of biodiversity persistence in relation to specific human land uses and land management actions. Available research demonstrates the potential contribution of biodiversity conservation in human-modified landscapes within all four ecosystem types and goes some way towards providing general conclusions that could support policy-making. Nonetheless, conservation success in human-modified landscapes is hampered by constraints requiring further scientific investment, e.g. deficiencies in the available research, uncertainties regarding implementation strategies, and difficulties of coexisting with biodiversity. However, information currently available can and should support efforts at individual, community, provincial, national, and international levels to support biodiversity conservation in human-modified landscapes.     

Hidden crown jewels: the role of tree crowns for bryophyte and lichen species richness in sycamore maple wooded pastures

Tree crowns typically cover the vast majority of the surface area of trees, but they are rarely considered in diversity surveys of epiphytic bryophytes and lichens, especially in temperate Europe. Usually only stems are sampled. We assessed the number of bryophyte and lichen species on stems and in crowns of 80 solitary sycamore maple trees (Acer pseudoplatanus) at six sites in wooded pastures in the northern Alps. The total number of species detected per tree ranged from 13 to 60 for bryophytes, from 25 to 67 for lichens, and from 42 to 104 for bryophytes and lichens considered together. At the tree level, 29 % of bryophyte and 61 % of lichen species were recorded only in the crown. Considering all sampled trees together, only 4 % of bryophyte, compared to 34 % of lichen species, were never recorded on the stem. Five out of 10 red-listed bryophyte species and 29 out of 39 red-listed lichen species were more frequent in crowns. The species richness detected per tree was unexpectedly high, whereas the proportion of exclusive crown species was similar to studies from forest trees. For bryophytes, in contrast to lichens, sampling several stems can give a good estimation of the species present at a site. However, frequency estimates may be highly biased for lichens and bryophytes if crowns are not considered. Our study demonstrates that tree crowns need to be considered in research on these taxa, especially in biodiversity surveys and in conservation tasks involving lichens and to a lesser degree also bryophytes.     

Traditional Livelihoods,Conservation and Meadow Ecology in Jiuzhaigou National Park,Sichuan, China

Jiuzhaigou National Park (JNP) is a site of global conservation significance. Conservation policies in JNP include the implementation of two national reforestation programs to increase forest cover and the exclusion of local land-use. We use archaeological excavation, ethnographic interviews, remote sensing and vegetation surveys to examine the implications of these policies for non-forest, montane meadows. We find that Amdo Tibetan people cultivated the valley for >2,000 years, creating and maintaining meadows through land clearing, burning and grazing. Meadows served as sites for gathering plants and mushrooms and over 40 % of contemporary species are ethnobotanically useful. Remote sensing analyses indicate a substantial (69.6 %) decline in meadow area between 1974 and 2004. Respondents report a loss of their “true history” and connections to the past associated with loss of meadows. Conservation policies intended to preserve biodiversity are unintentionally contributing to the loss of these ecologically and culturally significant meadow habitats.     

遥感在生物多样性研究中的应用进展

随着人口的持续增长, 人类经济活动对自然资源的利用强度不断升级以及全球气候变暖, 全球物种正以前所未有的速度丧失, 生物多样性成为了全球关注的热点问题。传统生物多样性研究以地面调查方法为主, 重点关注物种或样地水平, 但无法满足景观尺度、区域尺度以及全球尺度的生物多样性保护和评估需求。遥感作为获取生物多样性信息的另一种手段, 近年来在生物多样性领域发展迅速, 其覆盖广、序列性以及可重复性等特点使之在大尺度生物多样性监测和制图以及评估方面具有极大优势。本文主要通过文献收集整理, 从观测手段、研究尺度、观测对象和生物多样性关注点等方面综述了遥感在生物多样性研究中的应用现状, 重点分析不同遥感平台的技术优势和局限性, 并探讨了未来遥感在生物多样性研究的应用趋势。遥感平台按观测高度可分为近地面遥感、航空遥感和卫星遥感, 能够获取样地-景观-区域-洲际-全球尺度的生物多样性信息。星载平台在生物多样性研究中应用最多, 航空遥感的应用研究偏少主要受飞行成本限制。近地面遥感作为一个新兴平台, 能够直接观测到物种的个体, 获取生物多样性关注的物种和种群信息, 是未来遥感在生物多样性应用中的发展方向。虽然遥感技术在生物多样性研究中的应用存在一定的局限性, 未来随着传感器发展和多源数据融合技术的完善, 遥感能更好地从多个尺度、全方位地服务于生物多样性保护和评估。     

Modelling tree diversity in a highly fragmented tropical montane landscape

Aim There is an urgent need for conservation in threatened tropical forest regions. We explain and predict the spatial variation of α (i.e. within plot) and β (i.e. between plot) tree diversity in a tropical montane landscape subjected to a high deforestation rate. A major aim is to demonstrate the potential of a method that combines data from multiple sources (field data, remote sensing imagery and GIS) to evaluate and monitor forest diversity on a broad scale over large unexplored areas. Location The study covered an area of c. 3500 km² in the Highlands of Chiapas, southern Mexico. Methods We identified all of the tree species within 204 field plots (1000 m² each) and measured different environmental, human disturbance‐related, and spatial variables using remote sensing and GIS data. To obtain a predictive model of α tree diversity (Fisher's alpha) based on selected explanatory variables, we used a generalized linear model with a gamma error distribution. Mantel tests of matrix correspondence were used to determine whether similarities in floristic composition were correlated with similarities in the explanatory variables. Finally, we used a method that combines α and β tree diversity to define priority areas for conservation. Results The model for α tree diversity explained 44% of the overall variability, of which most was mainly related to precipitation, temperature, NDVI, and canopy (all relationships were positive, and quadratic for temperature and NDVI). There were no spatially structured regional factors that were ignored. Similarity in tree composition was correlated positively with climate and NDVI. Main conclusions The results were used to: (1) identify and assign conservation priority of unexplored areas that have high tree diversity, and (2) demonstrate the importance of several vegetation formations in the region's biodiversity. The method we present can be particularly useful in assessing regional needs and in developing local conservation strategies in poorly surveyed (and often at risk) tropical areas worldwide, where accessibility is usually limited.     

Bellwether of the Canaries: anthropogenic effects on the land snail fauna of the Canary Islands

Natural areas near human-modified landscapes experience factors that may affect local biodiversity at levels commensurate with natural environmental factors. The land snails of the Canary Islands provide excellent opportunities to evaluate the importance of anthropogenic agents in mediating the diversity and distribution of species. Land snails are particularly sensitive to disturbance and are an integral part of terrestrial ecosystems. This study analyzed the distributions and abundances of terrestrial macrosnail shell assemblages at 60 localities throughout the coastal scrub biome of the Canary Islands. This was accomplished using data on natural and anthropogenic variables to assess their relative importance in governing land snail diversity. A total of 34,801 dead shells represented a diverse malacofauna with highly localized endemism. Due to uncertain species identifications, samples from the 18 sites from the two easternmost islands are described, but excluded from statistical analyses. Regression tree analysis indicated that proximity to agricultural sites was the most important predictor of species diversity. Sites with no or very little agricultural area (≤ 0.167 km²) within a 1 km radius had significantly higher richness and diversity. These results have implications for Canary Islands conservation. Protected areas that are patchworks of natural and agricultural landscapes are still subject to native biodiversity loss because of anthropogenic impacts even when the footprint of agriculture is small.     

宏生态尺度上景观破碎化对物种丰富度的影响

生物多样性的地理格局及其形成机制是宏生态学与生物地理学的研究热点。大量研究表明,景观尺度上的生境破碎化对物种多样性的分布格局具有重要作用,但目前尚不清楚这种作用是否足以在宏生态尺度上对生物多样性地理格局产生显著影响。利用中国大陆鸟类和哺乳动物的物种分布数据,在100 km×100 km网格的基础上生成了这两个类群生物的物种丰富度地理格局,进一步利用普通最小二乘法模型和空间自回归模型研究了物种丰富度与气候、生境异质性、景观破碎化的相关关系。结果表明,景观破碎化因子与鸟类和哺乳动物的物种丰富度都具有显著的关联关系,其方差贡献率可达约30%—50%(非空间模型)和60%—80%(空间模型),略低于或接近于气候和生境异质性因子。方差分解结果显示,景观破碎化因子与气候和生境异质性因子的方差贡献率的重叠部分达20%—40%。相对鸟类而言,景观破碎化对哺乳动物物种丰富度的地理格局具有更高的解释率。     

Biodiversity of leaf-litter ants in fragmented tropical rainforests of Borneo: the value of publically and privately managed forest fragments

In view of the rapid rate of expansion of agriculture in tropical regions, attention has focused on the potential for privately-managed rainforest patches within agricultural land to contribute to biodiversity conservation. However, these sites generally differ in their history of forest disturbance and management compared with other forest fragments, and more information is required on the biodiversity value of these privately-managed sites, particularly in oil-palm dominated landscapes of SE Asia. Here we address this issue, using tropical leaf-litter ants in rainforest fragments surrounded by mature oil palm plantations in Sabah, Borneo as a model system. We compare the species richness and composition of ant assemblages in privately-managed forest fragments (‘high conservation value’ fragments; HCVs) with those in publically-managed fragments of forest (virgin jungle reserves; VJRs) and control sites in extensive tracts of primary forest. In this way, we test the hypothesis that privately-managed and publically-managed forest fragments differ in their species richness and composition as a result of differences in history and management and hence in habitat quality. In support of this hypothesis, we found that HCVs had much poorer habitat quality than VJRs, including lower sizes and densities of trees, less canopy cover, fewer dipterocarp trees and shallower leaf litter. Consequently, HCVs supported only half the species richness of ants in VJRs, which in turn supported 70 % of the species richness of control sites, with vegetation structure and composition explaining 77 % of the variation among forest fragments in ant species richness. HCVs were also much smaller than VJRs but there was only a weak relationship between fragment size and habitat quality, and species richness was not related to fragment size. VJRs supported 78 % of the 156 species found in extensive tracts of forest whereas HCVs supported only 22 %, which was only slightly higher than the proportion previously recorded in oil palm (19 %). These data support previous findings that publically-managed VJR fragments can make an important contribution to biodiversity conservation within agricultural landscapes. However, we suggest that for these HCVs to be effective as reservoirs of biodiversity, management is required to restore vegetation structure and habitat quality, for instance through enrichment planting with native tree species.