Catastrophes,connectivity and Allee effects in the design of marine reserve networks

Catastrophic events, like oil spills and hurricanes, occur in many marine systems. One potential role of marine reserves is buffering populations against disturbances, including the potential for disturbance-driven population collapses under Allee effects. This buffering capacity depends on reserves in a network providing rescue effects, setting up a tradeoff where reserves need to be connected to facilitate rescue, but also distributed in space to prevent simultaneous extinction. We use a set of population models to examine how dispersal ability and the disturbance regime interact to determine the optimal reserve spacing. We incorporate fishing in a spatially-explicit model to understand the effect of objective choice (e.g. conservation versus fisheries yield) on the optimal reserve spacing. We show that the optimal spacing between reserves increases when accounting for catastrophes with larger spacing needed when Allee effects interact with catastrophes to increase the probability of extinction. We also show that classic tradeoffs between conservation and fishing objectives disappear in the presence of catastrophes. Specifically, we found that at intermediate levels of disturbance, it is optimal to spread out reserves in order to increase both population persistence and to maximize spillover into non-reserve areas.     

VARIATION IN TOXIN PRODUCTION OF SYNCHRONIZED CULTURES OF CHRYSOCHROMULINA POLYLEPIS (PRYMNESIOPHYTA)

We studied spatial variability in giant kelp ( Macrocystis pyrifera ) forests at 84 sites along the west coast of North America in order to assess the impacts of the 1997–98 El Niño. Our sites spanned the geographic range of giant kelp in the Northern Hemisphere and were surveyed just before, immediately following, several months after, more than one year after, and nearly two years after the El Niño. Interspersion of sample units allowed us to compare the effects of this disturbance among spatial scales ranging from a few meters to more than a thousand kilometers. Variance components analyses revealed that El Niño shifted the relative importance of factors that regulate giant kelp communities from factors acting at the scale of a few meters (local control) to factors operating at hundreds of kilometers (regional control). Moreover, El Niño resulted in a near-to-complete loss of giant kelp populations throughout nearly two-thirds of the species' range. Evaluation of these effects along with oceanographic data (at the "appropriate" spatial scales), along with closer examination of giant kelp populations in the most severely impacted region (Baja) suggested that the among-region differences in giant kelp survival was due, at least in part, to El Niño-induced differences in ocean climate. Giant kelp recovery following El Niño was also scale-dependent, but driven by factors different from those of the disturbance. Here, we present results for several species of macroalgae in an attempt to relate the importance of El Niño to that of other processes in creating scale-dependent patterns of variability.     

基于Landsat时序影像和LandTrendr算法的森林保护区植被扰动研究——以陕西柴松和太白山保护区为例

跟踪森林自然保护区的森林变化及其时空特征,可为保护区生态保护评价提供科学依据。使用LandTrendr算法和谷歌地球引擎（GEE）的Landsat卫星时间序列数据,描述了柴松和太白山保护区的长期（1984-2018年）森林变化模式。对森林变化像元和稳定像元的总体识别精度达到93%,对扰动年探测的总体精度为89%。在柴松保护区,扰动年发生在2008年左右,大部分扰动由人类活动引起。在太白山保护区,扰动年主要发生在2013年,由自然因素造成。柴松和太白山保护区的森林扰动面积分别为42.74 hm²和23.68 hm²。柴松保护区的扰动斑块数多于太白山,表明柴松保护区自2004年建立后干扰频繁。本研究可以帮助研究人员和决策者了解这两个保护区的森林状况,可为森林生态系统的自然保护区保护评估提供基线信息。     

Large-Scale Geographic Variation in Distribution and Abundance of Australian Deep-Water Kelp Forests

Despite the significance of marine habitat-forming organisms, little is known about their large-scale distribution and abundance in deeper waters, where they are difficult to access. Such information is necessary to develop sound conservation and management strategies. Kelps are main habitat-formers in temperate reefs worldwide; however, these habitats are highly sensitive to environmental change. The kelp Ecklonia radiate is the major habitat-forming organism on subtidal reefs in temperate Australia. Here, we provide large-scale ecological data encompassing the latitudinal distribution along the continent of these kelp forests, which is a necessary first step towards quantitative inferences about the effects of climatic change and other stressors on these valuable habitats. We used the Autonomous Underwater Vehicle (AUV) facility of Australia’s Integrated Marine Observing System (IMOS) to survey 157,000 m² of seabed, of which ca 13,000 m² were used to quantify kelp covers at multiple spatial scales (10–100 m to 100–1,000 km) and depths (15–60 m) across several regions ca 2–6° latitude apart along the East and West coast of Australia. We investigated the large-scale geographic variation in distribution and abundance of deep-water kelp (>15 m depth) and their relationships with physical variables. Kelp cover generally increased with latitude despite great variability at smaller spatial scales. Maximum depth of kelp occurrence was 40–50 m. Kelp latitudinal distribution along the continent was most strongly related to water temperature and substratum availability. This extensive survey data, coupled with ongoing AUV missions, will allow for the detection of long-term shifts in the distribution and abundance of habitat-forming kelp and the organisms they support on a continental scale, and provide information necessary for successful implementation and management of conservation reserves.     

青藏高原高寒荒漠区藏羚生态廊道识别及其保护状况评估

青藏高原高寒荒漠区是以藏羚、藏野驴和野牦牛等为代表的濒危有蹄类野生动物全球的主要分布区域,然而该区域高速公路、铁路等基础设施建设所带来的人为干扰,往往对上述濒危有蹄类迁徙廊道产生干扰及阻隔效应.基于最小费用距离路径原理及其Linkage Mapper模型,本研究模拟识别了青藏高原高寒荒漠区藏羚种群的潜在廊道分布,并依据主要自然保护区(阿尔金、可可西里和羌塘)和廊道之间的关系,将潜在廊道划分为封闭廊道(保护区内部廊道)、连通廊道(保护区之间廊道)、开放廊道(保护区与其外部非保护区区域之间廊道)和外部廊道（保护区区域之外的廊道）4种类型,并比较了它们的空间分布特征及其受扰状况.结果表明：尽管青藏高原高寒荒漠区有蹄类生境及其廊道总体保护状况仍相对较好,但日益增强的人为干扰对连接主要保护区之间部分廊道生态功能的干扰和影响不容忽视;目前划片分区式保护区管理模式不利于对以藏羚羊为代表的濒危有蹄类迁徙廊道进行有效的整体性保护,未来需要建立基于生态完整性和廊道连通性,整合上述3大保护区,建立青藏高原高寒荒漠保护区网络体系,打破保护区间的行政边界割裂和管理体系分割,通过建立保护区之间信息、资源共享以及保护措施的统一协调机制,实现整个高寒荒漠区生态系统、高原珍稀濒危物种的统一保护管理,提升高寒荒漠保护区的整体保护效率.     

Exploitation and recovery of a sea urchin predator has implications for the resilience of southern California kelp forests

Size-structured predator–prey interactions can be altered by the history of exploitation, if that exploitation is itself size-selective. For example, selective harvesting of larger sized predators can release prey populations in cases where only large individuals are capable of consuming a particular prey species. In this study, we examined how the history of exploitation and recovery (inside marine reserves and due to fisheries management) of California sheephead (Semicossyphus pulcher) has affected size-structured interactions with sea urchin prey in southern California. We show that fishing changes size structure by reducing sizes and alters life histories of sheephead, while management measures that lessen or remove fishing impacts (e.g. marine reserves, effort restrictions) reverse these effects and result in increases in density, size and biomass. We show that predation on sea urchins is size-dependent, such that the diet of larger sheephead is composed of more and larger sized urchins than the diet of smaller fish. These results have implications for kelp forest resilience, because urchins can overgraze kelp in the absence of top-down control. From surveys in a network of marine reserves, we report negative relationships between the abundance of sheephead and urchins and the abundance of urchins and fleshy macroalgae (including giant kelp), indicating the potential for cascading indirect positive effects of top predators on the abundance of primary producers. Management measures such as increased minimum size limits and marine reserves may serve to restore historical trophic roles of key predators and thereby enhance the resilience of marine ecosystems.     

基于GIS的城市区域噪声空间分析

GIS技术在城市噪声管理中已经得到了广泛的应用,城市噪声监测部门在日常工作中会积累大量的数据资料,噪声地图的发展更是提供了大量的模拟噪声数据。从地学的视角来分析城市环境噪声问题,采用GIS空间分析软件Geoda支持的"箱线图"和"分层设色图"方法,通过分析现有的数据来发现噪声"热点",实施噪声评估,分析区域的环境噪声,还可轻易发现该区的噪声分布特点。这种分析方法将数据与相关的地理环境相对应,噪声数据反应的规律和噪声的空间格局得以直观地展现,分析结果可作为环境噪声研究、环境管理和政策制定的参考,是研究城市环境噪声状况的新途径。     

中国自然保护区空间分布特征

我国自然保护区经过60余年建设,在维护国家生态安全、保护生物多样性、保存自然遗产和改善生态环境质量等方面发挥着重要作用。研究系统整理了我国现有2672个自然保护区空间分布数据,形成了较为完整的空间信息数据库,从发展历程、保护类型、建设规模等方面进行了特征统计。运用地理集中指数和核密度指数等方法,对全国自然保护区从海陆分布、省级分布、时空分布、集聚分布等不同维度进行了空间分布特征分析。结果表明:(1)我国自然保护区数量和类型丰富,大致经历了"起步-停滞缓慢发展-稳步发展-快速发展-稳固完善"的5个发展阶段,以中小型的森林生态系统、野生动物、内陆湿地和水域生态系统自然保护区为主;(2)空间上为集聚分布,省域分布差异悬殊,沿"胡焕庸线"呈"西少东多、西聚东散"的特点;(3)不同类型和管理级别的自然保护区分布集群态势差异明显,形成了黄山-怀玉山、粤东北丘陵、南岭、武夷山等11个显著聚集区;(4)建设规模和连片聚集效应自西向东呈递减趋势,与我国地形的三级阶梯构造变化趋势存在紧密联系。最后,本文讨论了形成我国现有自然保护区空间格局的主要原因,包括客观自然条件及主观人为等因素,并结合我国自然保护区空间分布和建设发展中存在的问题进行了分析,从建立布局完善和海陆统筹的保护区网络,科学界定保护地类型,逐步优化自然保护区边界及稳步提升科研监测成效等方面提出了发展建议。在我国自然保护地体系由自然保护区向国家公园为主体的全面深化改革阶段,本研究弥补了现有研究成果的局限性和时效性问题,以期为未来自然保护区的空间布局优化及发展提供科学参考。     

SCALE‐DEPENDENT PATTERNS OF DISTURBANCE AND RECOVERY IN GIANT KELP FORESTS

We studied spatial variability in giant kelp (Macrocystis pyrifera) forests at 84 sites along the west coast of North America in order to assess the impacts of the 1997–98 El Niño. Our sites spanned the geographic range of giant kelp in the Northern Hemisphere and were surveyed just before, immediately following, several months after, more than one year after, and nearly two years after the El Niño. Interspersion of sample units allowed us to compare the effects of this disturbance among spatial scales ranging from a few meters to more than a thousand kilometers. Variance components analyses revealed that El Niño shifted the relative importance of factors that regulate giant kelp communities from factors acting at the scale of a few meters (local control) to factors operating at hundreds of kilometers (regional control). Moreover, El Niño resulted in a near‐to‐complete loss of giant kelp populations throughout nearly two‐thirds of the species' range. Evaluation of these effects along with oceanographic data (at the “appropriate” spatial scales), along with closer examination of giant kelp populations in the most severely impacted region (Baja) suggested that the among‐region differences in giant kelp survival was due, at least in part, to El Niño‐induced differences in ocean climate. Giant kelp recovery following El Niño was also scale‐dependent, but driven by factors different from those of the disturbance. Here, we present results for several species of macroalgae in an attempt to relate the importance of El Niño to that of other processes in creating scale‐dependent patterns of variability.     

Spatial Epidemiology and GIS in Marine Mammal Conservation Medicine and Disease Research

The use of spatial epidemiology and geographical information systems (GIS) facilitates the incorporation of spatial relationships into epidemiological investigations of marine mammal diseases and conservation medicine. Spatial epidemiology is the study of the spatial variation in disease risk or incidence and explicitly addresses spatial structures and functions that factor into disease. The GIS consists of input, management, analysis, and presentation of spatial disease data and can act as an integrative tool so that a range of varied data sources can be combined to describe different environmental aspects of wild animals and their diseases. The use of modern spatial analyses and GIS is becoming well developed in the field of marine mammal ecology and biology, but has just recently started to gain more use in disease research. The use of GIS methodology and spatial analysis in nondisease marine mammal studies is briefly discussed, while examples of the specific uses of these tools in mapping, surveillance and monitoring, disease cluster detection, identification of environmental predictors of disease in wildlife populations, risk assessment, and modeling of diseases, is presented. Marine mammal disease investigations present challenges, such as less consistent access to animals for sampling, fewer baseline data on diseases in wild populations, and less robust epidemiologic study designs, but several recommendations for future research are suggested. Since location is an integral part of investigating disease, spatial epidemiology and GIS should be incorporated as a data management and analysis tool in the study of marine mammal diseases and conservation medicine.     

小尺度海域空间评价单元划分技术研究——以福建省东山湾为例

科学合理的海域空间评价单元划分是各类海洋空间监测、评价、规划和管理的基础工作,对于保护海洋生态环境,实现海洋资源的可持续开发利用具有重大现实意义。然而,海洋的流动性、开放性、边界模糊性等特征,导致海洋空间评价单元划分较陆地而言更为复杂、困难。以福建省东山湾为例,提出一种适用于小尺度海域的空间评价单元划分技术方案,通过从化学属性、物理属性、生物学属性三个方面构建海域空间生态属性划分指标体系,进行空间分类评价,运用插值、叠加分析等GIS技术将东山湾划分为67个基本空间评价单元。研究结果不仅能为进一步划定东山湾海洋空间规划提供技术支持,同时为其他小尺度海域生态监测、评价、规划和管理提供科学参考。     

中国市域自然保护区时空格局演变特征

市域是自然保护地整合优化的具体实施单元,揭示市域自然保护区的时空格局演变特征和发展趋势对于全面建设中国特色自然保护地体系具有重要的现实意义。基于1975-2020年间隔5 a的10期中国自然保护区名录,通过标准差椭圆、探索性空间数据分析、空间Markov链等方法首次从市域尺度探讨了中国自然保护区的时空动态演变特征和发展趋势,并引入地学信息图谱构建其变化模式。结果表明:①中国市域自然保护区比例呈现先快速增长后逐步稳定的趋势,但整体仍以低值区为主。市域间自然保护区比例差异明显,逐步形成了“西高东低”的空间格局。重心整体表现为“东南-西北-东北”的迁移过程,重心移动距离和速度逐渐缩小。1990年以后,中国市域自然保护区比例始终呈现“东北-西南”向的空间分布格局。②市域自然保护区比例存在显著的空间相关性且相关性总体呈上升之势,但空间集聚水平的变化逐年缩小。局部空间异质性较强,高高和低低集聚区均呈扩张态势。③从变化模式图谱来看,中国市域自然保护区比例等级以“前期变化-低频-逐步提升”(ESC-LQ-T1)的方式进行,主要图谱类型为“空缺区转为低值区”。市域自然保护区比例等级类型转移具有稳定性和显著的时空异质性,后期出现了“俱乐部收敛”现象,且邻域背景在其动态变化过程中发挥着重要作用。未来要加强对空缺区和低值区市域单元的自然资源进行摸底评估,将其最有价值的区域纳入自然保护区,同时推广区域联合保护机制,促进自然保护地体系高质量建设。     

The role of marine reserves in the replenishment of a locally impacted population of anemonefish on the Great Barrier Reef

The development of parentage analysis to track the dispersal of juvenile offspring has given us unprecedented insight into the population dynamics of coral reef fishes. These tools now have the potential to inform fisheries management and species conservation, particularly for small fragmented populations under threat from exploitation and disturbance. In this study, we resolve patterns of larval dispersal for a population of the anemonefish Amphiprion melanopus in the Keppel Islands (southern Great Barrier Reef). Habitat loss and fishing appear to have impacted this population and a network of no‐take marine reserves currently protects 75% of the potential breeders. Using parentage analysis, we estimate that 21% of recruitment in the island group was generated locally and that breeding adults living in reserves were responsible for 79% (31 of 39) of these of locally produced juveniles. Overall, the network of reserves was fully connected via larval dispersal; however, one reserve was identified as a critical source of larvae for the island group. The population in the Keppel Islands also appears to be well‐connected to other source populations at least 60 km away, given that 79% (145 of 184) of the juveniles sampled remained unassigned in the parentage analysis. We estimated the effective size of the A. melanopus metapopulation to be 745 (582–993 95% CI) and recommend continued monitoring of its genetic status. Maintaining connectivity with populations beyond the Keppel Islands and recovery of local recruitment habitat, potentially through active restoration of host anemone populations, will be important for its long‐term persistence.     

Ocean zoning within a sparing versus sharing framework

The land-sparing versus land-sharing debate centers around how different intensities of habitat use can be coordinated to satisfy competing demands for biodiversity persistence and food production in agricultural landscapes. We apply the broad concepts from this debate to the sea and propose it as a framework to inform marine zoning based on three possible management strategies, establishing: no-take marine reserves, regulated fishing zones, and unregulated open-access areas. We develop a general model that maximizes standing fish biomass, given a fixed management budget while maintaining a minimum harvest level. We find that when management budgets are small, sea-sparing is the optimal management strategy because for all parameters tested, reserves are more cost-effective at increasing standing biomass than traditional fisheries management. For larger budgets, the optimal strategy switches to sea-sharing because, at a certain point, further investing to grow the no-take marine reserves reduces catch below the minimum harvest constraint. Our intention is to illustrate how general rules of thumb derived from plausible, single-purpose models can help guide marine protected area policy under our novel sparing and sharing framework. This work is the beginning of a basic theory for optimal zoning allocations and should be considered complementary to the more specific spatial planning literature for marine reserve as nations expand their marine protected area estates.     

Assessing Habitat Use by Snapper (Chrysophrys auratus) from Baited Underwater Video Data in a Coastal Marine Park

Baited Underwater Video (BUV) systems have become increasingly popular for assessing marine biodiversity. These systems provide video footage from which biologists can identify the individual fish species present. Here we explore the relevance of spatial dependence and marine park boundaries while estimating the distribution and habitat associations of the commercially and recreationally important snapper species Chrysophrys auratus in Moreton Bay Marine Park during a period when new Marine National Parks zoned as no-take or “green” areas (i.e., areas with no legal fishing) were introduced. BUV studies typically enforce a minimum distance among BUV sites, and then assume that observations from different sites are independent conditional on the measured covariates. In this study, we additionally incorporated the spatial dependence among BUV sites into the modelling framework. This modelling approach allowed us to test whether or not the incorporation of highly correlated environmental covariates or the geographic placement of BUV sites produced spatial dependence, which if unaccounted for could lead to model bias. We fitted Bayesian logistic models with and without spatial random effects to determine if the Marine National Park boundaries and available environmental covariates had an effect on snapper presence and habitat preference. Adding the spatial dependence component had little effect on the resulting model parameter estimates that emphasized positive association for particular coastal habitat types by snapper. Strong positive relationships between the presence of snapper and rock habitat, particularly rocky substrate composed of indurated freshwater sediments known as coffee rock, and kelp habitat reinforce the consideration of habitat availability in marine reserve design and the design of any associated monitoring programs.     

Gap Dynamics and Structure of Two Old-Growth Beech Forest Remnants in Slovenia

Context

Due to a long history of intensive forest exploitation, few European beech (Fagus sylvatica L.) old-growth forests have been preserved in Europe.

Material and Methods

We studied two beech forest reserves in southern Slovenia. We examined the structural characteristics of the two forest reserves based on data from sample plots and complete inventory obtained from four previous forest management plans. To gain a better understanding of disturbance dynamics, we used aerial imagery to study the characteristics of canopy gaps over an 11-year period in the Kopa forest reserve and a 20-year period in the Gorjanci forest reserve.

Results

The results suggest that these forests are structurally heterogeneous over small spatial scales. Gap size analysis showed that gaps smaller than 500 m² are the dominant driving force of stand development. The percentage of forest area in canopy gaps ranged from 3.2 to 4.5% in the Kopa forest reserve and from 9.1 to 10.6% in the Gorjanci forest reserve. These forests exhibit relatively high annual rates of coverage by newly established (0.15 and 0.25%) and closed (0.08 and 0.16%) canopy gaps. New gap formation is dependant on senescent trees located throughout the reserve.

Conclusion

We conclude that these stands are not even-sized, but rather unevenly structured. This is due to the fact that the disturbance regime is characterized by low intensity, small-scale disturbances.     

Climate‐driven disparities among ecological interactions threaten kelp forest persistence

The combination of ocean warming and acidification brings an uncertain future to kelp forests that occupy the warmest parts of their range. These forests are not only subject to the direct negative effects of ocean climate change, but also to a combination of unknown indirect effects associated with changing ecological landscapes. Here, we used mesocosm experiments to test the direct effects of ocean warming and acidification on kelp biomass and photosynthetic health, as well as climate‐driven disparities in indirect effects involving key consumers (urchins and rock lobsters) and competitors (algal turf). Elevated water temperature directly reduced kelp biomass, while their turf‐forming competitors expanded in response to ocean acidification and declining kelp canopy. Elevated temperatures also increased growth of urchins and, concurrently, the rate at which they thinned kelp canopy. Rock lobsters, which are renowned for keeping urchin populations in check, indirectly intensified negative pressures on kelp by reducing their consumption of urchins in response to elevated temperature. Overall, these results suggest that kelp forests situated towards the low‐latitude margins of their distribution will need to adapt to ocean warming in order to persist in the future. What is less certain is how such adaptation in kelps can occur in the face of intensifying consumptive (via ocean warming) and competitive (via ocean acidification) pressures that affect key ecological interactions associated with their persistence. If such indirect effects counter adaptation to changing climate, they may erode the stability of kelp forests and increase the probability of regime shifts from complex habitat‐forming species to more simple habitats dominated by algal turfs.     

Spillover of fish naïveté from marine reserves

Spillover of adult fish biomass is an expected benefit from no‐take marine reserves to adjacent fisheries. Here, we show fisher‐naïve behaviour in reef fishes also spills over from marine reserves, potentially increasing access to fishery benefits by making fishes more susceptible to spearguns. The distance at which two targeted families of fishes began to flee a potential fisher [flight initiation distance (FID)] was lower inside reserves than in fished areas, and this reduction extended outside reserve boundaries. Reduced FID persisted further outside reserves than increases in fish biomass. This finding could help increase stakeholder support for marine reserves and improve current models of spillover by informing estimates for spatial changes in catchability. Behavioural changes of fish could help explain differences between underwater visual census and catch data in quantifying the spatial extent of spillover from marine reserves, and should be considered in the management of adjacent fisheries.     

Estimating scale-dependency in disturbance impacts: El Niños and giant kelp forests in the northeast Pacific

Recent discussions on scaling issues in ecology have emphasized that processes acting at a wide range of spatial and temporal scales influence ecosystems and thus there is no appropriate single scale at which ecological processes should be studied. This may be particularly true for environmental disturbances (e.g. El Niño) that occur over large geographic areas and encompass a wide range of scales relevant to ecosystem function. However, it may be possible to identify the scale(s) at which ecosystems are most strongly impacted by disturbances, and thus provide a measure by which their impacts can be most clearly described, by assessing scale-dependent changes in the patterns of variability in species abundance and distribution. This, in turn, may yield significant insight into the relative importance of the various forcing factors responsible for generating these impacts. The 1997–98 El Niño was one of the strongest El Niños ever recorded. I examined how this event impacted giant kelp populations in the northeast Pacific Ocean at 90 sites ranging from central Baja California, Mexico to central California, USA. These sites spanned the geographic range of giant kelp in the Northeast Pacific and were surveyed just before, immediately following, several months after, more than 1 year after, and nearly 2 years after the El Niño. I used a hierarchical sample design to compare these impacts at five spatial scales spanning six orders of magnitude, from a few meters to more than 1,000 km. Variance Components Analyses revealed that the El Niño shifted control over giant kelp abundance from factors acting at the scale of a few meters (local control) to factors operating over hundreds to thousands of kilometers (regional control). Moreover, El Niño resulted in the near-complete loss of all giant kelp throughout one-half of the species range in the northeast Pacific Ocean. Giant kelp recovery following El Niño was far more complex and variable at multiple spatial scales, presumably driven by numerous factors acting at those scales. Recovery returned local control of giant kelp populations within 6 months in southern California, and within 2 years in Baja California.