Effects of agriculture,climate, and policy on NDVI change in a semi-arid river basin of the Chinese Loess Plateau

In 1999, the Grain for Green Project was implemented by the Chinese government. Since then, the vegetation of Zuli River Basin, a semi-arid river basin of the Chinese Loess Plateau, has been greatly changed. Clearly understanding the impact of natural and artificial factors on vegetation change is important for policy making and ecosystem management. In this study, spatio-temporal variations in vegetation cover in Chinese Zuli River Basin during 1999–2016 were investigated using Landsat normalized difference vegetation index (NDVI) data. Analyses of several indicators, including changes in NDVI in different slopes and land use changes and the relationships between climatic factors and NDVI change, were presented to quantitatively evaluate the effects of agriculture, climate, and policy on NDVI change. The NDVI in the Zuli River Basin increased during the study period, and the main contributors to this change were forest in 1999–2011, cropland, abandoned farmland, and grassland in 2009–2016, and land with slopes ≤ 15°. Land with slope > 15°, where the “Project” was implemented, slightly contributed to the increase in regional NDVI. In 1999–2011, the project (?98.16%) combined with climate change (?68.18%) showed negative effects on the increase in NDVI in the Zuli River Basin, but agriculture (22.28%) played a positive role in increasing this index. In 2009–2016 and 1999–2016, the project (38.45% and 35.25%, respectively), the project combined with climate change (49.83% and 46.30%, respectively), agriculture (18.61% and 23.30%, respectively), promoted increases in NDVI in the basin.     

Mass balanced based LCA of a common carp-lettuce aquaponics system

An aquaponics system (AS) is an integrated system that combines a recirculating aquaculture system and a hydroponics system (HS). It is designed to recover nutrients released from fish and transfer them to plants to provide a system more environmentally-friendly than the two systems working separately. As a result, several AS are under development, but little information is available about their overall performances. The aim of this study was to assess nutrient-use efficiency and environmental impacts of an AS, specifically a common carp-lettuce AS located in a greenhouse. Nutrient budgets of nitrogen (N) and phosphorus (P) were calculated and Life Cycle Assessment (LCA) was performed for the AS and for a lettuce Individual Hydroponics System (IHS), similar to the HS of the AS, operating in the greenhouse at the same time. The experiment was performed over a 52-day cycle, which corresponds to the growing time required to harvest marketable lettuce. The nutrient budgets were well balanced, with 24.6% of the N unaccounted-for, most likely due to N2 gas emission, and 6.6% of the P unaccounted-for, most likely due to having underestimated the quantity of sediment. At the beginning of the experiment, N represented 55.9%, 37.1% and 0.1% of the total N input in the formulated feed, stocked fish and lettuce seedlings, respectively. At the end of the experiment, N represented 47.6% and 0.4% of the total N input in the harvested fish and lettuce, respectively. At the beginning of the experiment, P represented 56.94%, 40.20% and 0.03% of the total P input in the formulated feed, stocked fish and lettuce seedlings, respectively. At the end of the experiment, P represented 51.52% and 0.42% of the total P input in the harvested fish and lettuce, respectively. LCA clearly indicated two environmental impact hotspots: the origin of nutrients and energy use. One kg of lettuce growth in the AS clearly had lower environmental impacts than that in the IHS for climate change, acidification, eutrophication, land competition and cumulative energy demand; however, a decrease in water dependence was not observed. The indicator for net primary production use highlighted the dependence of the AS on natural resources, especially fish meal and fish oil. Compared to the use of chemical nutrients in the IHS, the use of nutrients from formulated feed in the AS decreased climate change impact but increased the use of natural resources.     

A critical sites network for freshwater biodiversity in the Lake Victoria Basin

The Lake Victoria Basin (LVB) is known for its high levels of species richness and endemism. Freshwater ecosystems within this region are highly threatened, putting both biodiversity and human livelihoods at risk. Protected areas (PAs) should provide the foundation for conservation actions to tackle threats but currently poorly represent freshwater species. To address this issue, systematic conservation planning (Marxan) was used to identify networks of sites within the LVB for the conservation of freshwater biodiversity, based on existing Key Biodiversity Areas (KBAs) and PAs, and with minimal cost in terms of area and human impact. Networks were identified separately for threatened species and/or those endemic to the LVB, and those susceptible to the impacts of climate change. Here, these were combined to present an overall sites network for the conservation of freshwater biodiversity. Site‐level recommendations are provided as a scientific basis for the development and expansion of the existing network.     

Reproductive characteristics of the fishery important temperate demersal berycid Centroberyx gerrardi indicate greater reproductive output in regions of upwelling

The reproductive biology of Centroberyx gerrardi (Günther) was investigated across ~2,000 km of its southern Australian distribution, encompassing different jurisdictions and varying environmental features. Greater gonad mass and prevalence of spawning fish, along with lower ratios of lengths at maturity:maximum lengths and ages at maturity:maximum ages, were identified at the western‐most (Capes) and eastern‐most (Great Australian Bight; GAB) regions. Across the study region, spawning peaks in summer/autumn, when water temperatures are warmest. Regional differences in potential “reproductive output,” while not consistent with the eastward decline in mean monthly water temperature, may instead be related to summer upwelling in the Capes and GAB, driving greater oceanic productivity prior to peak spawning, supporting larval survival. In autumn, the prevailing southward and eastward flowing, downwelling Leeuwin Current (LC) strengthens, providing a dispersal mechanism along the west and south Australian coasts, but limiting upwelling effects. Predicted changes in environmental conditions and their potential impacts on C. gerrardi are discussed, in particular how these factors may affect recruitment to stocks and fisheries, requiring a better understanding of source‐sink relationships for this species. As environmental changes occur, management strategies to sustain fish resources must adapt to spatially variable and changing reproductive output and be collaborative across jurisdictions.     

青藏高原草地降水利用效率时空动态及对气候变化的响应

本研究利用CASA(Carnegie-Ames-Stanford Approach)模型模拟了2000—2013年青藏高原草地净植被生产力(Net Primary Production，NPP)，结合实测数据、气象数据和土地覆被数据计算了草地降水利用效率（PUE），探究其时空分布特征，以及不同草地类型PUE及其对气候变化的响应。结果表明：青藏高原草地PUE在研究年限内呈现波动增加趋势，增加速率为每年0.0035 g·m^-2·mm^-1，14 a的平均值为0.38 g·m^-2·mm^-1。PUE的空间分布具有明显的异质性，呈现东部高、中西部低的基本格局。PUE分布在0.2～0.4 g·m^-2·mm^-1之间的比例最大，占青藏高原总面积的55.63%，呈减少趋势的区域主要分布在青藏高原的北部和西部，以及东部的边界地区，呈增加趋势的地区集中在研究区的中部和南部。研究年限内PUE的变异系数分布在0.07～0.85之间，变化稳定的区域所占面积最大，为总面积的43.43%，主要分布在唐古拉山脉和横断山脉附近。不同草地类型间PUE均值存在差异，具体表现为：草甸（1.06 g·m^-2·mm^-1）>坡面草地（0.80 g·m^-2·mm^-1）>平原草地（0.30 g·m^-2·mm^-1）>高山与亚高山草甸（0.29 g·m^-2·mm^-1）>荒漠草地（0.23 g·m^-2·mm^-1）>高山与亚高山草地（0.094 g·m^-2·mm^-1）。总体上，青藏高原草地PUE与降水成负相关关系，而与气温呈正相关，PUE的变化对降水响应更加敏感。     

Looking beyond the horizon: An early warning system to keep marine mammal information relevant for conservation

1. Important marine mammal areas (IMMAs) are discrete portions of habitat, important to marine mammal species, that have the potential to be delineated and managed for conservation. Although IMMAs are not a blueprint for marine protected areas or other conservation designations, they are useful for providing a foundation for marine spatial planning and systematic conservation planning that can then lead to protected areas or special spatial regulations. To be most useful for supporting management and conservation, however, the information coming out of IMMAs needs to reflect current conditions.
2. An ‘early warning system’ is proposed with a generic set of indicators to flag when marine mammal species in IMMAs require management interventions due to changing distributions or decreasing populations. Rather than signifying that quantitative thresholds have been reached, these indicators comprise alerting information derived from visual or acoustic census, satellite imagery analysis, whale‐watching logs, or increases in mortality reported by stranding networks that can trigger additional targeted research.
3. Although it is possible that in some regions data will be sufficient to provide quantifiable indicators, the system is meant to rely on existing data sources, and be adaptable to the circumstances of each region.
4. Regional expert groups can utilize early warning system information and feed it into IMMA‐related spatial planning in two ways: by nominating additional areas of interest, and by providing a scientific rationale for revising IMMA boundaries, to be considered at the next decadal IMMA regional expert workshop.
5. IMMA‐driven consolidation of information that is as current as possible will prove valuable for enhancing regional cooperation to conserve marine mammals, and will be useful as countries implement new protected areas to conserve marine mammals and other marine biodiversity.

     

Use of state‐space modelling to identify ecological covariates associated with trends in pinniped demography

1. Identifying and understanding ecological drivers that influence wildlife populations is challenging but critical for conservation. This typically requires integrating long‐term data on both the population and potential drivers within statistical models that are suitable for analysing these complex relationships. State‐space models offer one method for integrating such data. Once implemented within a Bayesian framework, these analyses can control for multifactorial influences on populations, allowing one to extract otherwise undetectable correlations between the environment and the underlying, inferred demography.
2. In the Moray Firth, Scotland, harbour seals have been counted annually for 30 years (1988–2018). A Bayesian state‐space model was used to explore whether patterns in vital rates were correlated to changes in prey abundance, inter‐specific competition (grey seal abundance), environmental variables [the North Atlantic Oscillation (NAO) and sea‐surface temperature], or level of biotoxins (saxitoxin and domoic acid) in the Moray Firth waters.
3. The credible interval of the posterior distributions of three of these covariate coefficients (sandeel proxy, NAO and grey seal abundance) suggested that there was a relationship between those covariates and vital rates. Both the sandeel proxy and NAO showed a positive correlation with fecundity, whereas grey seal abundance had a negative impact on pup survival.
4. This work demonstrates how an integrated state‐space modelling approach can bring together diverse data sets and point to important interactions with prey, and with other predators in the system. This suggests that the wider‐scale management of UK harbour seal populations with their contrasting temporal trends needs to account for variation in the marine ecosystem at appropriate spatial scales, in line with current policy concerning spatial planning in the marine environment.

     

The importance of Southern Ocean frontal systems for the improvement of body condition in southern elephant seals

1. As top predators, it has been suggested that southern elephant seals serve as sentinels of ecosystem status to inform management and conservation.
2. This is because southern elephant seals annually undertake two large‐scale foraging migrations for 2–3 and 7–8 months to replenish resources after fasting during breeding and moulting and often rely on dynamic macroscale latitudinal fronts to provide favourable foraging through aggregating prey.
3. Yet it is largely unknown whether southern elephant seals respond to changes in frontal systems over the years, whether their foraging success is associated with specific frontal systems shifts, and how flexible southern elephant seals populations are in behaviourally adapting to changes in frontal systems.
4. This study examines the relationship between frontal systems and the resource acquisition of 64 southern elephant seals during four post‐moult and three post‐breeding migrations between 2005 and 2010.
5. Satellite‐relay‐data‐loggers provided in situ measurements concurrent with >27,500 dive profiles to define fronts and interfrontal zones between the Subtropical Frontal Zone and the Southern Boundary of the Antarctic Circumpolar Current. For >430,000 in situ measurements water mass properties could be identified.
6. Generally, southern elephant seals associate more frequently with more southerly, higher‐latitude fronts/zones. Body condition improvements related to a given frontal system or water mass vary strongly according to year, season, month and sex.
7. The variability in body condition improvements is higher in some frontal systems than in others, probably owing to shifts in the Subantarctic and Polar Front.
8. During a migration, some individuals stay within ≤3 frontal systems, whilst others change between several frontal systems and primarily improve their body condition in upper ocean waters.
9. Southern elephant seals do not trace particular water masses across frontal systems, and both surface and deep foraging strategies are used.
10. This suggests that southern elephant seals do not target particular water masses but adjust foraging and movement strategies to exploit boundary areas at which mixing and prey aggregation is high.
11. The large behavioural plasticity towards the spatio‐temporal variability in the different oceanographic regions they encounter could indicate resilience against environmental changes.