Phytomass and plant functional diversity in early restoration of the degraded, semi-arid grasslands in northern China     

Y. Chu  W.-M. He  H.-D. Liu  J. Liu  X.-W. Zhu  M. Dong   《Journal of Arid Environments》2006,67(4):678-687

We analysed vegetation data recorded in the degraded lowland grasslands in Otindag Sandland during the first 4-years of restoration (2001–2004) to investigate: (1) the contribution of individual plant functional type (PFT) to PFT diversity of community and (2) the relationships between primary productivity and biodiversity both at species and PFT levels. Sixteen PFTs were distinguished based on the following traits: (1) life-span (annual vs. perennial); (2) photosynthetic pathway (C₃ vs. C₄); (3) reproductive mode (clonal vs. non-clonal); and (4) growth form (grass vs. forb). Analysis of data indicates that density, coverage, number of species, phytomass, and relative importance of PFTs depended strongly on life-span, photosynthetic pathway, reproductive mode and growth form. Phytomass was significantly correlated with PFT diversity, but not species diversity. However, the relationship between phytomass and PFT diversity varied greatly with year, with a positive relationship in 2001 and 2004 and a negative one in 2002 and 2003. As the restoration proceeds, the perennial C₃ clonal grass became the greatest contributor to PFT diversity.  相似文献   

Species diversity and ecology of Tonle Sap Great Lake, Cambodia     

Ian C. Campbell  Colin Poole  Wim Giesen  John Valbo-Jorgensen 《Aquatic Sciences - Research Across Boundaries》2006,68(3):355-373

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Predation of the beetle Rhantus sikkimensis (Coleoptera: Dytiscidae) on the larvae of Chironomus Meigen (Diptera: Chironomidae) of the Darjeeling Himalayas of India     

Gautam Aditya  Goutam Kumar Saha   《Limnologica》2006,36(4):251-257

The dytiscid beetle Rhantus sikkimensis, Regimbart, 1899 (Coleoptera: Dytiscidae), a member of the freshwater insect communities of the Darjeeling Himalayas, were noted to predate on the coexisting larvae of Chironomus sp. Meigen. Evaluation of predation by R. sikkimensis on Chironomus sp. larvae, in the laboratory, revealed that a single adult morph of R. sikkimensis could kill and consume on an average 10–90 and 10–78 numbers of small and large Chironomus sp. larvae, respectively, per day, depending on the prey density. The attack rate ranged between 520 and 537, and the handling time ranged between 4.3 and 8.6 depending on the size of the preys. The predation varied with respect to predator density also, with a maximum of 151 larvae killed by three predators per day. Two indices of predation, ingestion rate (IR) ranging between 13.33 and 74.15 larvae/day/predator and clearance rate (CR) ranging between 19.67 and 39.99 L prey/day/predator, varied with the prey size and predator density, significantly, when the predation was observed for 9 consecutive days, at two predator densities. It was also noted that R. sikkimensis predated on an average 9.8 larvae of Chironomus sp. and 1 larva of Culex sp., when the larvae of both the species are present together as preys, showing a preference for the Chironomus sp. larvae.  相似文献   

Beyond total area protected: A new set of metrics to measure progress in building a robust protected area estate     

《Global Environmental Change》2019

With protected areas identified as the primary tool to halt the loss of biodiversity, the Convention on Biological Diversity has set targets for protected area expansion. Increasingly, concerns are being raised that target-driven growth, where targets focus largely on quantity (total area protected) rather than quality, may fail to achieve their intended biodiversity outcomes. Therefore, it is important to assess whether growth in area protected is translating into a more robust system of protected areas that better safeguard biodiversity. In this study, we propose a set of seven indicators, drawing on the body of evidence for the elements of protected area design and management associated with better biodiversity outcomes. Many of the features of effective design and management interact with one another, making it essential to use a suite of indicators and consider progress relative to trends across all of these indicators. We implemented the proposed indicators for the Australian National Reserve System, which has undergone significant growth over the past two decades. Our findings demonstrate that relying on trends in total area protected can obscure negative trends in other important indicators which suggest many protected areas in Australia are under increasing pressure. Meanwhile, the level of resourcing for management has not kept pace with increases in total area protected and has certainly not scaled with changes in pressures on protected areas. It is important that the global conservation community strive for a more nuanced set of indicators for conservation progress to identify whether growth in area protected has, or has not, translated into a more robust and effective system of protected areas. Given that most of the indicators we propose can be populated with existing data, we believe this approach could be achievable for protected areas globally.  相似文献   

First ornithopod remains from the Bajo de la Carpa Formation (Santonian,Upper Cretaceous), northern Patagonia,Argentina     

《Cretaceous Research》2018

In the last decades, the Argentinian ornithopod record has been increased with new and diverse bone remains found along all the Upper Cretaceous. Most of them are very incomplete and represent taxa of different size. As result, the studies about the palaeobiodiversity of the Ornithopoda clade in South America are complex. In this paper, new postcranial remains of an indeterminate medium-sized ornithopod from the Santonian Bajo de la Carpa Formation (Rincón de los Sauces, Neuquén province) are presented. They present diagnostic features of the Ornithopoda clade, and several characters that relate them with other Argentinian ornithopods, especially with the medium-sized members of the Elasmaria clade sensu Calvo et al. (2007) (Macrogryphosaurus and Talenkauen). The postcranial material allows to identificate at least three different ontogenetic stages: adult, subadult more immature and subadult. These bones are the first record of Ornithopoda for the Bajo de la Carpa Formation and one of the very scarce Santonian records of this clade in South America. The diversity of the Late Cretaceous South American ornithopods presents two clear distributions: the Cenomanian-Santonian was characterized by small and medium euiguanodonts and elasmarian; and the Campanian–Maastrichtian by the medium sized elasmarian and large sized hadrosaurids.  相似文献   

Using information layers for mapping grassland habitat distribution at local to regional scales     

《International Journal of Applied Earth Observation and Geoinformation》2015

The Natura 2000 network of protected sites is one of the means to enable biodiversity conservation in Europe. EU member states have to undertake surveillance of habitats and species of community interest protected under the Habitat Directive. Remote sensing techniques have been applied successfully to monitor biodiversity aspects according to Natura 2000, but many challenges remain in assessing dynamics and habitat changes outside protected sites. Grasslands are among the most threatened habitats in Europe. In this paper we tested the integration of expert knowledge into different standard classification approaches to map grassland habitats in Schleswig Holstein, Germany. Knowledge about habitat features is represented as raster information layers, and used in subsequent grassland classifications. Overall classification accuracies were highest for the maximum likelihood and support vector machine approaches using RapidEye time series, but results improved for specific grassland classes when information layers were included in the classification process.  相似文献   

Very high resolution Earth observation features for monitoring plant and animal community structure across multiple spatial scales in protected areas     

《International Journal of Applied Earth Observation and Geoinformation》2015

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Managing catch of marine megafauna: Guidelines for setting limit reference points     

《Marine Policy》2015

Limit reference points (LRPs) for catch, which correspond to thresholds to undesirable population or ecosystem states, offer a consistent, objective approach to management evaluation and prioritization across fisheries, species, and jurisdictions. LRPs have been applied successfully to manage catch of some marine megafauna (elasmobranchs, marine reptiles, seabirds, and marine mammals) in some jurisdictions, such as the use of Potential Biological Removal (PBR) to manage incidental mortality of marine mammals under the U.S. Marine Mammal Protection Act. However, implementation of ecosystem-based management is still in its infancy globally, and LRPs have not yet been widely adopted for marine megafauna, particularly for incidental catch. Here, guidelines are proposed for estimating catch LRPs for marine megafauna, with particular attention to resolving common technical and political challenges, including (1) identifying management units, population thresholds, and risk tolerances that align with common conservation goals and best practices, (2) choosing catch LRP estimators, (3) estimating input parameters such as abundance and productivity, (4) handling uncertainty, and (5) dealing with mismatches between management jurisdictions and population boundaries. The problem of cumulative impacts across sectors is briefly addressed. These guidelines, grounded in marine policy, science, precedent, and lessons learned, should facilitate wider application of catch LRPs in evaluation and management of fisheries impacts on marine megafauna, in support of global commitments to conserve biodiversity and manage fisheries responsibly.  相似文献   

Yield and catch changes in a Mediterranean small tuna trap: a warming change effect?          下载免费PDF全文

Riccardo Cattaneo‐Vietti  Valentina Cappanera  Michela Castellano  Paolo Povero 《Marine Ecology》2015,36(2):155-166

Since the 17th century, the Tonnarella of Camogli, a small tuna trap, has been used to catch pelagic fish along the western coast of the Portofino Promontory (Ligurian Sea, Northwestern Mediterranean). The availability of long‐term datasets on fish yields (1950–1974 and 1996–2011), with information related to the seawater temperatures and the North Atlantic Oscillation (NAO), has allowed us to study the qualitative and quantitative changes in fish yields in the last decade and the possible relationships with the seasonal anomalies of temperature that have occurred in the Ligurian Sea. In 1950–1974, yields remained relatively constant over time (average of 35.6 ± 8.7 t·year^?1). From 1996 through 2011, yields were high (42.9 ± 15.9 t·year^?1) but inconsistent with strong annual variability in catches. The primary catches are Seriola dumerili, Auxis rochei, Trachurus spp. and Sarda sarda. Changes in species composition have occurred as well: S. dumerili, Sardinella sp. and Belone belone have appeared recently. Moreover, a significant decrease in the boreal scombroid (Scomber scombrus) and an increase of warm‐temperate carangids and other typically Southern Mediterranean species such as Coryphaena hippurus and Sphyraena viridensis, appear to be linked to the warming of the surface water layer, particularly evident in the Ligurian Sea, for the last 10 years. The analysis of this kind of trend may be a powerful tool for assessing structural changes of the pelagic fish community in the Ligurian Sea (Northwestern Mediterranean).  相似文献   

Local and temporal variations in near‐shore macrobenthic communities associated with submarine groundwater discharges          下载免费PDF全文

João Encarnação   Francisco Leitão  Pedro Range  David Piló  Maria Alexandra Chícharo  Luís Chícharo 《Marine Ecology》2015,36(4):926-941

The influence of submarine groundwater discharges (SGD) on the dynamics of coastal ecosystems is receiving increasing scientific attention, although our knowledge of this issue still remains insufficient. Understanding the ecological response of coastal ecosystems to SGD dynamics is important in order to evaluate and predict changes in coastal communities. The aim of the present study was to characterize the effect of groundwater discharge on subtidal soft‐bottom macrofaunal assemblages in the south coast of Portugal (Algarve) at different times of the year and under different discharge regimes. Sediment macrofauna was sampled twice per season in spring and summer 2011 in two locations: one under influence of SGD (Olhos de Água) and one not under that influence (Arrifes). The results showed that differences in community structure between locations occurred mainly during spring, when the magnitude of groundwater discharge was higher. Several individual taxa were strongly associated with the SGD, particularly during spring: the polychaete families Magelonidae and Oweniidae; the isopod Cyathura carinata; and the bivalves Tellimya ferruginosa and Tellina fabula. Some of these taxa are already considered indicators of SGD, whereas others merit further investigation. The average similarity among samples was consistently larger in the location with SGD and the average similarity between the two locations was generally higher during spring, indicating that SGD promote stability in macrobenthic communities across time and space. SGD were also associated with higher values of Chlorophyll a (Chl a), fine sediments and total abundance of organisms (particularly suspension feeders). This suggests that differences between locations are associated with SGD and mediated by nutrient fluxes and sediment transport, or their interaction.  相似文献