Tree species classification in subtropical forests using small-footprint full-waveform LiDAR data

The accurate classification of tree species is critical for the management of forest ecosystems, particularly subtropical forests, which are highly diverse and complex ecosystems. While airborne Light Detection and Ranging (LiDAR) technology offers significant potential to estimate forest structural attributes, the capacity of this new tool to classify species is less well known. In this research, full-waveform metrics were extracted by a voxel-based composite waveform approach and examined with a Random Forests classifier to discriminate six subtropical tree species (i.e., Masson pine (Pinus massoniana Lamb.)), Chinese fir (Cunninghamia lanceolata (Lamb.) Hook.), Slash pines (Pinus elliottii Engelm.), Sawtooth oak (Quercus acutissima Carruth.) and Chinese holly (Ilex chinensis Sims.) at three levels of discrimination. As part of the analysis, the optimal voxel size for modelling the composite waveforms was investigated, the most important predictor metrics for species classification assessed and the effect of scan angle on species discrimination examined. Results demonstrate that all tree species were classified with relatively high accuracy (68.6% for six classes, 75.8% for four main species and 86.2% for conifers and broadleaved trees). Full-waveform metrics (based on height of median energy, waveform distance and number of waveform peaks) demonstrated high classification importance and were stable among various voxel sizes. The results also suggest that the voxel based approach can alleviate some of the issues associated with large scan angles. In summary, the results indicate that full-waveform LIDAR data have significant potential for tree species classification in the subtropical forests.     

雷州半岛红树林海区的鱼类种类调查

对雷州半岛8个红树林分布区设站位进行了生物多样性调查,其中获得鱼类127种,分别隶属于15目58科100属。以鲈形目最多,共27科49属65种,占51.2％。种类出现最多的科为(鱼叚)虎鱼科。采获种类最多的站位为北潭。各站位之间鱼类种类具有一定的差异性。调查获得的鱼类体型偏小,大部分种类具有食用价值,其中16种已为人工增养殖的对象。     

Conservation in a complex management environment: The by-catch of sea turtles in North Carolina’s commercial fisheries

Despite a powerful, federal legislative framework established to protect threatened and endangered species in the United States, conservation actions can be hindered by the complexity of the full management structure. This is particularly true when state and federal agencies share the responsibility to conserve endangered species. To illustrate this point, this paper describes the management of sea turtle by-catch in commercial fisheries within the state waters of North Carolina. It reviews past and present by-catches, summarizes state and federal efforts intended to reduce sea turtle by-catch, and discusses the challenges posed by the involvement of multiple agencies with conflicting objectives. It concludes by recommending fundamental changes to this management framework and, in particular, proposes the establishment of a multilayered stakeholder group that would work to reduce sea turtle by-catch while supporting vibrant commercial fisheries in the state.     

Ten guiding principles for the delineation of priority habitat for endangered small cetaceans

The adoption of endangered species laws in various nations has intensified efforts to better understand, and protect, at-risk species or populations, and their habitats. In many countries, delineating a portion of a species' habitat as particularly worthy of protection has become a mantra of these laws. Unfortunately, the laws themselves often provide scientists and managers with few, if any, guidelines for how to define such habitat. Conservationists and scientists may view protecting part of the habitat of an endangered species as an ineffectual compromise, while managers may be under pressure to allow a range of human activities within the species' habitat. In the case of small cetaceans, establishing boundaries for such areas can also be complicated by their mobility, the fluid nature of their environment, and the often ephemeral nature of their habitat features. The convergence of multiple human impacts in coastal waters around the world is impacting many small cetaceans (and other species) that rely on these areas for feeding, reproducing, and resting. The ten guiding principles presented here provide a means to characterize the habitat needs of small, at-risk cetaceans, and serve as a basis for the delineation of ‘priority habitat’ boundaries. This conceptual approach should facilitate a constructive discourse between scientists and managers engaged in efforts to recover endangered species. The degree to which the recovery of an at-risk species can be reconciled with sustainable economic activity will depend in part on how well these principles are incorporated into the delineation of priority habitat.     

舟山渔场及邻近海域头足类(Cephalopod)种类组成和数量分布

根据2006年8月、2007年1月、5月和11月4个季节在舟山渔场及邻近海域(29°30'N-32°00'N,127°00'E以西)开展海洋生态系统综合调查所获得的头足类资料,用渔获率作为头足类分布的数量指标,分析了该海域的头足类种类组成、数量分布以及季节变化趋势.结果表明,该海域共鉴定头足类25种,隶属于3目8科9属...     

澳门沿海的底栖贝类

报道了澳门沿海底栖贝类56种,隶属40属27科3纲,并对主要可发展养殖的经济贝类作了介绍.     

察尔汗盐湖区生物种类调查及评价

随着察尔汗盐湖资源开发活动强度的不断增加,各种人工设施和水利工程数量日渐增加,对生态环境的影响也逐步明显,因此本研究对盐湖区生态多样性和生态景观格局的变化趋势开展系统调查。主要通过梳理文献和对察尔汗盐湖周边的重点补给河流格尔木河的干支流及附属人工防洪堤水库水体开展生物多样性调查与评估,查明生物种类、分布、数量,评估盐湖区生物多样性现状,并从保护生物多样性的角度为盐湖区生态环境保护提供建议。     

Macroinvertebrates in the bed sediment of the Yellow River

Extensive agricultural,industrial and urban development in the Yellow River,China,have modified the sediment-water balance,flow and inundation regimes,longitudinal connectivity,integrity of riparian vegetation,and water quality.Macroinvertebrate assemblages in the bed sediment of main channel and major reservoirs of the Yellow River are described in detail for the first time.A total of 74 taxa comprising 17 taxa of oligochaetes,48 taxa of aquatic insects,5 taxa of molluscs,and 4 taxa of other animals were recorded.A range of feeding guilds were represented,including, collector-gatherers(32 taxa),predators(17 taxa),scrapers(16 taxa),shredders(6 taxa)and collector-filterers(2 taxa).Both the mean density and biomass of macroinvertebrates were significantly higher in sites located in the artificial reservoirs compared with the main river channel. Assemblages varied spatially;Oligochaetes dominated assemblages in upper reaches,insects dominated in middle reaches and other animals(e.g.Crustacea)dominated in lower reaches. Collector-gatherers were dominant throughout the entire river.Classification analysis identified five site-groups on the basis of macroinvertebrate presence/absence:downstream of reservoirs;vegetated sites;reservoir sites;polluted sites,and;lower-reach sites.Lower macroinvertebrate richness,density and biomass,compared with other similar large rivers,were attributed to modification of the sediment-water balance and associated disturbance of benthic habitats.Pollution,stability of sediment and sediment concentration combined to influence the distribution of macroinvertebrates.This knowledge will substantially benefit the recent focus on the health and environmental water requirements of the Yellow River.     

The effect of thermal pollution on benthic foraminiferal assemblages in the Mediterranean shoreface adjacent to Hadera power plant (Israel)

The thermal pollution patch of Hadera power plant was used as a natural laboratory to evaluate the potential long-term effects of rise in Eastern Mediterranean SST on living benthic foraminifera. Their sensitivity to environmental changes makes foraminifera ideal for this study. Ten monthly sampling campaigns were performed in four stations located along a temperature gradient up to 10 °C from the discharge site of heated seawater to a control station. The SST along this transect varied between 25/18 °C in winter and 36/31 °C in summer. A significant negative correlation was found between SST in all stations and benthic foraminiferal abundance, species richness and diversity. The total foraminiferal abundance and species richness was particularly low at the thermally polluted stations especially during summer when SST exceeded 30 °C, but also throughout the entire year. This indicates that thermal pollution has a detrimental effect on benthic foraminifera, irrelevant to the natural seasonal changes in SST.     

Macroalgal diversity along the Baltic Sea salinity gradient challenges Remane's species-minimum concept

Remane’s species-minimum concept, which states that the lowest number of taxa occurs at the horohalinicum (5-8 psu), was tested by investigating macroalgal diversity on hard substrates along the natural salinity gradient in the Baltic Sea. Field data on species occurrence and abundance were collected by SCUBA diving along 10 transects of the Finnish, Swedish and German coasts, covering a salinity range from 3.9 to 27 psu. Macroalgal species numbers declined steadily with salinity, decreasing until 7.2 psu was reached, but in the horohalinicum, a marked reduction of species number and a change in diversity were indicated by the Shannon index and evenness values. The non-linear decrease in macroalgal diversity at 5-8 psu and the lack of increase in species numbers at salinities below 5 psu imply a restricted applicability of Remane’s species-minimum concept to macroalgae.