The Ecological Strategies of Sea Turtles

By employing concepts such as "option" and "strategy" from gametheory, this study derives an ecologically-oriented dendrogramof the probable evolutionary history and the present relationshipsof sea turtles. An "armored tank" strategy is seen as differentiatingthe first ancestral testudines from the stem reptiles and providingenduring advantages while simultaneously imposing basic restrictionson all later forms. A "flipper" strategy is postulated as basicto development of the sea turtle line, again imposing limitationswhile conferring selective advantage. Modern sea turtle speciesare grouped into three lineages representing strategies of habitat-typeresource partitioning (a split-habitat, migratory pattern, aneritic residence pattern, and a pelagic residence pattern).Within the split-habitat, migratory group, further resource-partitioningby food-type separates the herbivorous Chelonia mydas populationsfrom omnivorous Eretmochelys imbricata and the (apparently)carnivorous Chelonia depressa. Herbivory is seen as integralto the split-habitat, migratory strategy and C. mydas is consideredthe most "traditional" species, with the migratory habit secondarilylost in the other two. At the same time, the enhanced philopatryselected for by the migration strategy is viewed as responsiblefor the fact that C. mydas seems to have the most active race-formationof the three species. Further habitat-type partitioning in theneritic group, together with food-type partitioning, separatesCaretta caretta from the two Lepidochelys species. L. kempiis represented as a consequence of Panamanian separation fromL. olivacea following the last establishment of the isthmusas a land barrier. The third, pelagic residence, strategy isrepresented by Dermochelys coriacea, with little further differentiationof the line. The paper attempts to show that the evolution ofsea turtles has been ecologically logical, that most conceivableniches for marine turtles are presently filled successfully,and that some predictions may be made with regard to gaps inour existing information.     

Some Aspects of the Reproductive Biology of Limonium vulgare Mill., and Limonium humile Mill.

The germination of two species of salt-marsh plants Limoniumvulgare Mill., and L. humile Mill., is investigated in relationto their ecology. Germination is inhibited by sea water, butgermination even in fresh water is low. Inhibition of germinationby sea water is negatively correlated with water uptake. However,a treatment in sea water stimulates subsequent germination infresh water. The effect of the sea-water treatment appears tobe one of osmotic shock which weakens the seed coat. Variationin response to the treatment is partly genetical and partlyenvironmental. Seeds in different parts of the salt-marsh willbe subject to differing conditions, both during seed developmentand during the interval between seed maturation and seed dispersal.In connection with this the effect of leaching by sea waterand fresh water is considered. The response to a sea-water treatmentvaries with time. Considered in the long term it shows somecyclical variation which might correspond with the tidal cycle.It is shown that seeds of Limonium can survive long periodsin sea water. There is a slow rate of germination during immersion.Most of those seeds which do not germinate in sea water surviveto germinate rapidly in fresh water. The response to oxygenconcentration, light, and temperature is also investigated.Experiments on seedling growth and establishment show the needfor fresh water and a suitable substrate. Mud gives a lowergermination but a higher survival, while sand gives a highergermination but a lower survival. The dispersal of Limoniumseeds in nature is investigated. Seeds of Limonium are mostabundant in the drift line, but even these only represent asmall fraction of the total produced. It is considered thatreproduction by seed is only important when a new area is beinginvaded. Subsequent reproduction is largely by vegetative spread.The ecological implications of the germination experiments arediscussed.     

2009年第五届“现代生态学讲座”国际会议综述

"现代生态学讲座"系列会议是由国内外华人生态学家联合发起、为加强现代生态学的新理论、新观点、新方法和热点问题的交流与合作的国际会议.总结了2009年6月27～29日在兰州大学举行的第五届现代生态学讲座国际会议的全部二十五场报告,围绕"宏观生态学和可持续发展科学"的会议主题,分别从森林生态学、草地生态学、全球变化生态学、根际和土壤生态学、分子和行为生态学以及农业生态学等角度进行了分类总结.全部报告可归纳为"生态系统服务功能的物质基础"和"生态系统服务的生态学机制"两个大的基础理论问题,而解决问题的途径必须在人类-自然耦合生态系统的大框架下进行探索.对该会议的进一步改善提出了一些建议.     

A national approach for mapping and quantifying habitat-based biodiversity metrics across multiple spatial scales

Ecosystem services, i.e., services provided to humans from ecological systems have become a key issue of this century in resource management, conservation planning, and environmental decision analysis. Mapping and quantifying ecosystem services have become strategic national interests for integrating ecology with economics to help understand the effects of human policies and actions and their subsequent impacts on both ecosystem function and human well-being. Some aspects of biodiversity are valued by humans in varied ways, and thus are important to include in any assessment that seeks to identify and quantify the benefits of ecosystems to humans. Some biodiversity metrics clearly reflect ecosystem services (e.g., abundance and diversity of harvestable species), whereas others may reflect indirect and difficult to quantify relationships to services (e.g., relevance of species diversity to ecosystem resilience, cultural value of native species). Wildlife habitat has been modeled at broad spatial scales and can be used to map a number of biodiversity metrics. In the present study, we present an approach that (1) identifies mappable biodiversity metrics that are related to ecosystem services or other stakeholder concerns, (2) maps these metrics throughout a large multi-state region, and (3) compares the metric values obtained for selected watersheds within the regional context. The broader focus is to design a flexible approach for mapping metrics to produce a national-scale product. We map 20 biodiversity metrics reflecting ecosystem services or other aspects of biodiversity for all vertebrate species except fish. Metrics include species richness for all vertebrates, specific taxon groups, harvestable species (i.e., upland game, waterfowl, furbearers, small game, and big game), threatened and endangered species, and state-designated species of greatest conservation need, and also a metric for ecosystem (i.e., land cover) diversity. The project is being conducted at multiple scales in a phased approach, starting with place-based studies, then multi-state regional areas, culminating into a national-level atlas. As an example of this incremental approach, we provide results for the southwestern United States (i.e., states of Arizona, New Mexico, Nevada, Utah, and Colorado) and portions of two watersheds within this region: the San Pedro River (Arizona) and Rio Grande River (New Mexico). Geographic patterns differed considerably among metrics across the southwestern study area, but metric values for the two watershed study areas were generally greater than those for the southwestern region as a whole.     

Some Problems of Sea Turtle Ecology

Tagging programs have revealed parts of the patterns of reproductivemigration of some sea turtle populations, but much of the ecologicgeography of the species remains unknown. The present papertakes stock of the advances and gaps in our knowledge of thegroup. Kemp's ridley and the Tortuguero green turtle populationare used as sources of examples of these strong and weak areas.Possible causes of one-season nesting and its bearing on seaturtle demography are discussed. An apparent dichotomy in the"lost-year" ecology of the Tortuguero green turtles and Kemp'sridley is suggested. Some hatchlings of both evidently driftaway in major currents, while others pass this stage circlingin local eddies—Chelonia in the West Caribbean Gyre andLepidochelys kempi within the Gulf of Mexico.     

Chemical Interactions in the Cactus-Microorganism-Drosophila Model System of the Sonoran Desert

The Cactus-Microorganism-Drosophila Model System of the SonoranDesert represents an excellent paradigm of the role of chemistryin plant-animal interactions. In this system, four species ofendemic Drosophila feed and reproduce in necrotic tissue offive species of columnar cacti. Studies over the past 35 yrhave characterized a myriad of interactions between the threemajor components of the model system. The cacti contain a varietyof allelochemicals which are primarily responsible for the highlyspecific pattern of host plant utilization exhibited by thedesert Drosophila. Plant chemistry, through its effect on themicrobially produced volatile patterns, is further involvedin host specificity because the flies use the volatile patternto cue in on necroses in the appropriate species of cactus.The metabolic activities of microorganisms (bacteria and yeasts)living in the necrosis can affect the substrate chemistry inboth positive and negative ways (i.e., acting to increase orto decrease the toxicity of the substrate). Finally, cactuschemistry may affect drosophilid mating behavior since larvalrearing substrate has been shown to influence adult hydrocarbonepicuticular composition. In D. mojavensis, adult hydrocarbonprofile has been implicated as a determinant of mate choiceleading to premating isolation between geographically isolatedpopulations that use chemically different cactus substrates.Current research is focused on the evolution and regulationof genes whose products (cytochrome P450 enzymes) are involvedin the specific insect-host plant relationships which existbetween the Drosophila species and the cactus species. There are many reasons why investigators choose to focus theirresearch efforts on what are referred to as "model systems."Typically included among these would be the idea that modelsystems are easier to study because they are less complex thanother scientific situations. At the same time, model systemsshould be representative of more complex, natural systems sothat information that is obtained from their study is broadlyapplicable. For almost a century, the fruit fly, Drosophilamelanogaster, has served as a model organism for the study ofgenetics. As a genetic paradigm, Drosophila is more tractableto scientific investigation than most organisms and has providedimportant insights into a wide variety of human maladies fromalcohol abuse to neurological brain disorders (Bellen, 1998).Similarly, the interrelationships of the columnar cacti andthe cactophilic Drosophila species of the Sonoran Desert have,for the past 35 yr, provided an excellent model system withwhich to study relevant questions in evolution, ecological genetics,and chemical ecology. The intent of this article is to brieflyreview and characterize the chemical interactions between theplants (cacti) and animals (Drosophila) of this model system,and, in addition, provide some thoughts on possible future directionsfor integrative approaches in this research area.     

Discontinuite hydrobiologique dans le detroit du Pas-de-Calais

Hydrobiological studies in the Straits of Dover show a differencebetween the characteristics of the French coastal water andthe open sea water. A cruise between Boulogne-sur-mer and Dover(October 15, 1985) confirms the existence of a frontal area(4 miles off the French coast). This area is characterized byan increase of the salinity (1%) and decrease of the suspendedmatter content (from 27 to 20 mg l^–1), of primary production(from 15 to 3 mg C m^–3h^–1) and of chlorophyll aconcentration (from 4.5 to 1.5 mg m^–3). The presence ofdifferent zooplanktonic species in the two water masses alsocharacterizes this discontinuity. Oncaea sp., Corycaeus anglicus,Centropages typicus and Calanus helgolandicus are indicatorspecies of open sea water, while Cyciopina littoralis and ‘Saphirella’are only present in coastal water.     

Projecting global land-use change and its effect on ecosystem service provision and biodiversity with simple models

Background

As the global human population grows and its consumption patterns change, additional land will be needed for living space and agricultural production. A critical question facing global society is how to meet growing human demands for living space, food, fuel, and other materials while sustaining ecosystem services and biodiversity [1].

Methodology/Principal Findings

We spatially allocate two scenarios of 2000 to 2015 global areal change in urban land and cropland at the grid cell-level and measure the impact of this change on the provision of ecosystem services and biodiversity. The models and techniques used to spatially allocate land-use/land-cover (LULC) change and evaluate its impact on ecosystems are relatively simple and transparent [2]. The difference in the magnitude and pattern of cropland expansion across the two scenarios engenders different tradeoffs among crop production, provision of species habitat, and other important ecosystem services such as biomass carbon storage. For example, in one scenario, 5.2 grams of carbon stored in biomass is released for every additional calorie of crop produced across the globe; under the other scenario this tradeoff rate is 13.7. By comparing scenarios and their impacts we can begin to identify the global pattern of cropland and irrigation development that is significant enough to meet future food needs but has less of an impact on ecosystem service and habitat provision.

Conclusions/Significance

Urban area and croplands will expand in the future to meet human needs for living space, livelihoods, and food. In order to jointly provide desired levels of urban land, food production, and ecosystem service and species habitat provision the global society will have to become much more strategic in its allocation of intensively managed land uses. Here we illustrate a method for quickly and transparently evaluating the performance of potential global futures.     

Response of Pleistocene Coral Reefs to Environmental Change Over Long Temporal Scales

SYNOPSIS. TWO studies from the Pleistocene coral reef fossilrecord demonstrate the sensitivity of reef communities to bothlocal environmental parameters and habitat reduction. In thefirst study, Pleistocene reef coral assemblages from Papua NewGuinea show pronounced constancy in taxonomic composition andspecies diversity between 125 and 30 ka (thousand years). Spatialdifferences in reef coral community composition during successivehigh stands of sea level were greater among sites of the sameage than among reefs of different ages, even though global changesin sea level, atmospheric CO₂ concentration, tropical benthichabitat area, and temperature varied at each high sea levelstand. Thus, local environmental variation associated with runofffrom the land had greater influence on reef coral communitycomposition than variation in global climate and sea level.Proportional sampling from a regional species pool does notexplain the temporal persistence and local factors likely playeda major role. Examination of coral reef response to global changeshould not only involve regional diversity patterns but alsolocal ecological factors, and the interactive effects of localand global environmental change. In the second study, Pleistocene extinction of two widespread,strictly insular species of Caribbean reef corals, Pocilloporacf. palmata (Geister, 1975) and an organ-pipe growth form ofthe Montastraea "annularis" species complex, was natural anddid not involve gradual decrease in range and abundance, butwas sudden (thousands of years) throughout the entire range.One explanation is that sea level drop at the Last Glacial Maximum(LGM—18 ka) resulted in a threshold of habitat reduction,and caused disruption of coral metapopulation structure. Thresholdeffects predicted by metapopulation dynamics may also explainthe apparent paradox of the large amount of degraded modernreef habitat without any known modern-day reef coral extinctions.The rapid extinction of widespread Pleistocene species emphasizesthe vulnerability of reef corals in the face of present rapidenvironmental and climatic change.     

Behavioral Adaptations of Terrestrial Isopods

In their response to environmental stimuli, terrestrial isopodsshow various trends that are correlated with their ecology andphysiology. With the transition from sea to the littoral zone (Ligia), orientationto light changes from positive to negative. Yet, since theseisopods are positively hygrokinetic even at very high humidities,their hygroreaction is of greater significance than their photoreaction. In isopods from mesic habitats (Oniscus, Porcellio, Armadillidium)photoreaction becomes of less significance than in littoralspecies, until in some species it reverts to positive (Armadillidium).Sometimes the positive photoreaction occurs only at high temperatures(Porcellio), a pattern of behavior correlated with thermoregulationby evaporative cooling. Similarly, in mesic species the responseto humidity becomes less significant than in littoral species,resuming importance mainly when the isopods become dehydrated(Armadillidium). Finally, in isopods from xeric habitats in semi-arid and desertregions (Armadillo, Venezillo), photoreaction is strongly negativeexcept in Hemilepistus at lower temperatures. All of these isopodsare positively hygrokinetic only at low humidities and are stronglynegatively thermoactive, indicating a drop in activity at hightemperatures. The photonegative response in these isopods isstronger than the hygroreaction.     

Hypoxic Reptiles: Blood Gases, Body Temperature and Control of Breathing

Our contribution to this symposium is a review of recent modelsand experimental cdata on oxygen homeostasis in vertebrateswith normal intracardiac shunts; i.e., amphibians and reptiles.We focus on the interactions among hemoglobin function, bodytemperature regulation, and cardiovascular shunts under normalconditions (i.e., breathing fresh air at or near sea level)and during external hypoxia (e.g., altitude, burrows) and internalhypoxia (e.g., anemia, hemorrhage). Mathematical models andexperimental data suggest that animals with venous admixturefrom cardiovascular shunts will show biphasic arterial and mixedvenous Po₂ responses to warming; i.e., first increasing andthen, as the dissociation curve shifts too far to the right,decreasing. This has implications for many physiological functionsincluding oxygen consumption by tissues, control of breathing,as well as preferred body temperature and its regulation. Wepresent some of the recent experiments that have explored theseimplications.     

Invasive species denialism: a reply to Ricciardi and Ryan

This paper offers a defense against ad hominem aspersions cast in this journal by Ricciardi and Ryan (Biol Invasions 20(3):549–553, 2018) who allege that several articles I wrote represent “invasive species denialism” and “science denialism.” I summarize the arguments found in those articles. They are (1) science cannot define ecological “harm” and thus cannot measure its risk; (2) invasion biologists rely on tautologies, i.e., definitions of concepts like “biodiversity” and “ecosystem intactness,” that exclude exotic species; (3) no empirical evidence shows that introduced plants have been significant causes of extinction; (4) biologists cannot tell by observing a species whether it is native or a naturalized alien; and (5) debates over the meanings and measurements of key concepts in invasion biology have passed the point of diminishing returns. These arguments may be wrong but none is “similar to the denialism that has affected climate science and medical science” as Ricciardi and Ryan aver.     

Consciousness and Theoretical Behaviorism

There are three domains of experience that concern studentsof behavior: Domain 1. The domain of felt experience, the phenomenologicaldomain. Domain 2. The domain of physiology, the real-time functioningof the brain. Domain 3. The domain of behavioral data, "intersubjectivelyverifiable" reports and judgments by experimental subjects.Consciousness has meanings in each of these domains. Domain1 consciousness is beyond the reach of science as public knowledge.Empathy and plausible inference may tell us that our spouse,or our dog, is as conscious as we are. Science cannot. Researchin Domains 2 and 3 permits us to infer similarities and differencesbetween human and non-human psychology. Unfortunately, thesewill never permit us to know ‘what it is like’ tobe another creature. An example from the study of motion perceptionillustrates the point that the fruitless attempt to answer thisquestion can actually impede the objective study of behavioralprocesses we share with non-human animals.     

The Contributions of Sea Ice Algae to Antarctic Marine Primary Production

The seasonally ice-covered regions of the Southern Ocean havedistinctive ecological systems due to the growth of microalgaein sea ice. Although sea ice microalgal production is exceededby phytoplankton production on an annual basis in most offshoreregions of the Southern Ocean, blooms of sea ice algae differconsiderably from the phytoplankton in terms of timing and distribution.Thus sea ice algae provide food resources for higher trophiclevel organisms in seasons and regions where water column biologicalproduction is low or negligible. A flux of biogenic materialfrom sea ice to the water column and benthos follows ice melt,and some of the algal species are known to occur in ensuingphytoplankton blooms. A review of algal species in pack iceand offshore plankton showed that dominance is common for threespecies: Phaeocystis antarctica, Fragilariopsis cylindrus andFragilariopsis curta. The degree to which dominance by thesespecies is a product of successional processes in sea ice communitiescould be an important in determining their biogeochemical contributionto the Southern Ocean and their ability to seed blooms in marginalice zones.     

Undaria pinnatifida: A case study to highlight challenges in marine invasion ecology and management

Marine invasion ecology and management have progressed significantly over the last 30 years although many knowledge gaps and challenges remain. The kelp Undaria pinnatifida, or “Wakame,” has a global non‐native range and is considered one of the world's “worst” invasive species. Since its first recorded introduction in 1971, numerous studies have been conducted on its ecology, invasive characteristics, and impacts, yet a general consensus on the best approach to its management has not yet been reached. Here, we synthesize current understanding of this highly invasive species and adopt Undaria as a case study to highlight challenges in wider marine invasion ecology and management. Invasive species such as Undaria are likely to continue to spread and become conspicuous, prominent components of coastal marine communities. While in many cases, marine invasive species have detectable deleterious impacts on recipient communities, in many others their influence is often limited and location specific. Although not yet conclusive, Undaria may cause some ecological impact, but it does not appear to drive ecosystem change in most invaded regions. Targeted management actions have also had minimal success. Further research is needed before well‐considered, evidence‐based management decisions can be made. However, if Undaria was to become officially unmanaged in parts of its non‐native range, the presence of a highly productive, habitat former with commercial value and a broad ecological niche, could have significant economic and even environmental benefit. How science and policy reacts to the continued invasion of Undaria may influence how similar marine invasive species are handled in the future.     

Salmonella spp., Vibrio spp., Clostridium perfringens, and Plesiomonas shigelloides in Marine and Freshwater Invertebrates from Coastal California Ecosystems

The coastal ecosystems of California are highly utilized by humans and animals, but the ecology of fecal bacteria at the land–sea interface is not well understood. This study evaluated the distribution of potentially pathogenic bacteria in invertebrates from linked marine, estuarine, and freshwater ecosystems in central California. A variety of filter-feeding clams, mussels, worms, and crab tissues were selectively cultured for Salmonella spp., Campylobacter spp., Escherichia coli-O157, Clostridium perfringens, Plesiomonas shigelloides, and Vibrio spp. A longitudinal study assessed environmental risk factors for detecting these bacterial species in sentinel mussel batches. Putative risk factors included mussel collection near higher risk areas for livestock or human sewage exposure, adjacent human population density, season, recent precipitation, water temperature, water type, bivalve type, and freshwater outflow exposure. Bacteria detected in invertebrates included Salmonella spp., C. perfringens, P. shigelloides, Vibrio cholerae, Vibrio parahaemolyticus, and Vibrio alginolyticus. Overall, 80% of mussel batches were culture positive for at least one of the bacterial species, although the pathogens Campylobacter, E. coli-O157, and Salmonella were not detected. Many of the same bacterial species were also cultured from upstream estuarine and riverine invertebrates. Exposure to human sewage sources, recent precipitation, and water temperature were significant risk factors for bacterial detection in sentinel mussel batches. These findings are consistent with the hypothesis that filter-feeding invertebrates along the coast concentrate fecal bacteria flowing from land to sea and show that the relationships between anthropogenic effects on coastal ecosystems and the environmental niches of fecal bacteria are complex and dynamic.     

Bioenergetic prediction of climate change impacts on northern mammals

Climate change will likely alter the distribution and abundanceof northern mammals through a combination of direct, abioticeffects (e.g., changes in temperature and precipitation) andindirect, biotic effects (e.g., changes in the abundance ofresources, competitors, and predators). Bioenergetic approachesare ideally suited to predicting the impacts of climate changebecause individual energy budgets integrate biotic and abioticinfluences, and translate individual function into populationand community outcomes. In this review, we illustrate how bioenergeticscan be used to predict the regional biodiversity, species rangelimits, and community trophic organization of mammals underfuture climate scenarios. Although reliable prediction of climatechange impacts for particular species requires better data andtheory on the physiological ecology of northern mammals, tworobust hypotheses emerge from the bioenergetic approaches presentedhere. First, the impacts of climate change in northern regionswill be shaped by the appearance of new species at least asmuch as by the disappearance of current species. Second, seasonallyinactive mammal species (e.g., hibernators), which are largelyabsent from the Canadian arctic at present, should undergo substantialincreases in abundance and distribution in response to climatechange, probably at the expense of continuously active mammalsalready present in the arctic.     

海洋生物多样性损害与沿海地区经济增长关系实证研究

海洋生物多样性是海洋生态系统服务的基础,保护海洋生物多样性不仅对维持地球生态系统的功能至关重要,也与人类福祉密切相关。基于沿海11个省区生态系统亚健康程度指标和物种多样性损害指标,运用面板回归模型对中国沿海地区经济增长与海洋生物多样性损害的关系进行实证考察。研究结果表明：(1)海洋生态系统亚健康程度与沿海地区经济增长之间存在显著的线性关系,随着经济增长,典型海洋生态系统亚健康状态占比呈现出持续上升趋势。此外,实施排污费制度和建立海洋自然保护区有利于抑制海洋生态系统的恶化。(2)海洋物种多样性损害与沿海地区经济增长之间存在显著“倒U”型关系,随着经济增长,海洋物种多样性损害呈现先上升后下降的态势,转折点为人均GDP 45145元,目前海南省、广西壮族自治区、河北省未跨过转折点。此外,排污费制度有利于抑制海洋物种多样性损害,而沿海地区目前的产业结构加重了海洋物种多样性损害。根据实证分析结果,海洋生态系统健康尚未出现拐点,沿海地区经济增长如果建立在对生态环境破坏的基础上,则势必会造成生物多样性的损害。因此从规范海域利用方式,完善海岸生态保护红线划定,加强生态系统的监测与管理,保持绿色可持续的...