Local Ecological Factors Research Articles

Mapping Physiological Suitability Limits for Malaria in Africa Under Climate Change.

We mapped current and future temperature suitability for malaria transmission in Africa using a published model that incorporates nonlinear physiological responses to temperature of the mosquito vector Anopheles gambiae and the malaria parasite Plasmodium falciparum. We found that a larger area of Africa currently experiences the ideal temperature for transmission than previously supposed. Under future climate projections, we predicted a modest increase in the overall area suitable for malaria transmission, but a net decrease in the most suitable area. Combined with human population density projections, our maps suggest that areas with temperatures suitable for year-round, highest-risk transmission will shift from coastal West Africa to the Albertine Rift between the Democratic Republic of Congo and Uganda, whereas areas with seasonal transmission suitability will shift toward sub-Saharan coastal areas. Mapping temperature suitability places important bounds on malaria transmissibility and, along with local level demographic, socioeconomic, and ecological factors, can indicate where resources may be best spent on malaria control.

Parasite species richness and intensity of interspecific interactions increase with latitude in two wide-ranging hosts.

Although the latitudinal diversity gradient is a well-known and general pattern, the mechanisms structuring it remain elusive. Two key issues limit differentiating these. First, habitat type usually varies with latitude, precluding a standardized evaluation of species richness. Second, broad-scale and local factors hypothesized to shape diversity patterns covary with one another, making it difficult to tease apart independent effects. Examining communities of parasites in widely distributed hosts can eliminate some of these confounding factors. We quantified diversity and interspecific interactions for trematode parasites infecting two similar snail species across 27 degrees of latitude from 43 locations in tropical and temperate oceans. Counter to typical patterns, we found that species richness, levels of parasitism, and intensity of intraguild predation increased with latitude. Because speciation rates are precluded from driving diversity gradients in this particular system, the reversed gradients are likely due to local ecological factors, specifically, increased productivity and stability. We highlight how this system may serve as a useful tool to provide insight into what processes drive diversity gradients in general.

Single-Nucleotide Polymorphisms Reveal Spatial Diversity Among Clones of Yersinia pestis During Plague Outbreaks in Colorado and the Western United States.

In western North America, plague epizootics caused by Yersinia pestis appear to sweep across landscapes, primarily infecting and killing rodents, especially ground squirrels and prairie dogs. During these epizootics, the risk of Y. pestis transmission to humans is highest. While empirical models that include climatic conditions and densities of rodent hosts and fleas can predict when epizootics are triggered, bacterial transmission patterns across landscapes, and the scale at which Y. pestis is maintained in nature during inter-epizootic periods, are poorly defined. Elucidating the spatial extent of Y. pestis clones during epizootics can determine whether bacteria are propagated across landscapes or arise independently from local inter-epizootic maintenance reservoirs. We used DNA microarray technology to identify single-nucleotide polymorphisms (SNPs) in 34 Y. pestis isolates collected in the western United States from 1980 to 2006, 21 of which were collected during plague epizootics in Colorado. Phylogenetic comparisons were used to elucidate the hypothesized spread of Y. pestis between the mountainous Front Range and the eastern plains of northern Colorado during epizootics. Isolates collected from across the western United States were included for regional comparisons. By identifying SNPs that mark individual clones, our results strongly suggest that Y. pestis is maintained locally and that widespread epizootic activity is caused by multiple clones arising independently at small geographic scales. This is in contrast to propagation of individual clones being transported widely across landscapes. Regionally, our data are consistent with the notion that Y. pestis diversifies at relatively local scales following long-range translocation events. We recommend that surveillance and prediction by public health and wildlife management professionals focus more on models of local or regional weather patterns and ecological factors that may increase risk of widespread epizootics, rather than predicting or attempting to explain epizootics on the basis of movement of host species that may transport plague.

Dispersal strength determines meta‐community structure in a dendritic riverine network

AbstractAimMeta‐community structure is a function of both local (site‐specific) and regional (landscape‐level) ecological factors, and the relative importance of each may be mediated by the dispersal ability of organisms. Here, we used aquatic invertebrate communities to investigate the relationship between local and regional factors in explaining distance decay relationships (DDRs) in fragmented dendritic stream networks.LocationDryland streams distributed within a 400‐km2 section of the San Pedro River basin, south‐eastern Arizona, USA.MethodsWe combined fine‐scale local information (flow and habitat characteristics) with regional‐scale information to explain DDR patterns in community composition of aquatic invertebrate species with a wide range of dispersal abilities. We used a novel application of a landscape resistance modelling approach (originally developed for landscape genetic studies) that simultaneously assessed the importance of local and regional ecological factors as well as dispersal ability of organisms.ResultsWe found evidence that both local and regional factors influenced aquatic invertebrate DDRs in dryland stream networks, and the importance of each factor depended on the dispersal capacities of the organisms. Local and weak dispersers were more affected by site‐specific factors, intermediate dispersers by landscape‐level factors, and strong dispersers showed no discernable pattern. This resulted in a strongly hump‐shaped relationship between dispersal ability and landscape‐level factors, where only moderate dispersers showed evidence of DDRs. Unlike most other studies of dendritic networks, our results suggest that overland pathways, using perennial refugia as stepping‐stones, might be the main dispersal route in fragmented stream networks.Main conclusionsWe suggest that using a combination of landscape and local distance measures can help to unravel meta‐community patterns in dendritic systems. Our findings have important conservation implications, such as the need to manage river systems for organisms that span a wide variety of dispersal abilities and local ecological requirements. Our results also highlight the need to preserve perennial refugia in fragmented networks, as they may ensure the viability of aquatic meta‐communities by facilitating dispersal.

Spatial distribution and composition of waterbirds in relation to limnological conditions in the Amazon basin

The main hypothesis is that waterbird richness in Amazonian lakes differs between white- and black-waters, and has gradients in species com- position relating to lake-to-lake differences in shape, depth, water transparency, habitat richness, and pro- ductivity. I tested a complementary hypothesis that bird assemblages respond to variations in lake char- acteristics over a regional scale, and to neighboring aquatic components, called water body richness, including rivers, channels, and ponds. Bird surveys were conducted by circumnavigating 70 lakes along 1,000 km of Amazon River floodplains. To test these hypotheses, a non-metric multiple-dimensional scal- ing ordination complemented by multiple linear models was used to determine relationships between bird richness and assemblage composition, and biotic and abiotic lake characteristics. At a local scale, lake shape, water transparency, and trophic status influence bird assemblages. At a regional scale, differences among sites in water body richness, produced by Amazon River tributaries, and the two water types, are determinants of variation in composition of waterbird assemblages. The results indicate that waterbird assemblage composition within Amazonian flood- plains does result from links in processes operating at both spatial scales as predicted by neutral theory or influenced by local ecological factors as predicted by niche theory.

Biogeographically distinct controls on C3 and C4 grass distributions: merging community and physiological ecology

AbstractAimC4 photosynthesis is an adaptation that maintains efficient carbon assimilation in high‐light, high‐temperature conditions. Due to the importance of C4 grasses for carbon and surface energy fluxes, numerous models have been proposed to describe their spatial distribution and forecast their responses to climate change. These models often rely on broad climatic predictors (e.g. temperature and precipitation) but fail to integrate other ecologically relevant factors like disturbance and competition, which may modify realized C3/C4 grass distributions. Here, we present a combined evaluation of the contribution of ecological factors and climatic predictors to realized C3/C4 grass distributions. We consider multiple biogeographic regions of North America using a multisource database of over 40,000 vegetation plots.LocationThe conterminous United States of America (USA).MethodsWe identified a comprehensive pool of climatic models in the literature and used information theoretic criteria to select a primary climatic predictor of C3 and C4 grass distributions. Subsequently, the best model was combined with ecological predictors (e.g. fire, tree cover) using a multiple regression framework and tested within eight regions.ResultsSurprisingly, grass‐dominated communities across the USA exist largely in C3‐ or C4‐dominated states. Transitions between C3/C4 dominance were best explained by models that integrated temperature and precipitation with ecological factors that varied according to region. For some regions, like Eastern Temperate Forests, local ecological factors were comparable in strength to broad‐scale climatic predictors of C3/C4 abundance.Main conclusionLocal ecological factors modify C3/C4 grass responses to broad‐scale climatic drivers in ways that manifest at regional scales. In Eastern Temperate Forests, for example, C4 grass abundances are maintained below climatic expectations where tree cover creates light limitation but above expectations where frequent fires reduce tree cover. Thus, local ecological factors, which vary among biogeographic regions, contribute to large‐scale climate disequilibrium.

Regional metacommunities in two coastal systems: spatial structure and drivers of plant assemblages

AbstractAimBiogeographical patterns in metacommunities are still poorly understood, and different processes are expected to occur in different habitats. We analysed the regional plant metacommunities of coastal habitats to test whether (1) the influence of space and climate differs between two habitats differentiated along the seashore–inland gradient, and (2) regional variation in species composition of these habitats can be ascribed to different metacommunity paradigms.LocationThe entire coast of the Iberian Peninsula, south‐western Europe.MethodsWe collected data on the plant species composition of coastal sites on sand dunes across 3000 km of coastline. The sites were classified into two habitats corresponding to shifting and stable sand dunes, and divided into three distinct geographical regions: Cantabrian, Atlantic and Mediterranean. We assessed the geographical structure of the species composition using ordination, estimates of species turnover and spatial autocorrelation. We then used multivariate models and variation partitioning to test the influence of climatic and spatial effects. Analyses were conducted for the whole data set and the geographical subsets.ResultsMetacommunities from shifting and stable dunes showed similar spatial patterns, with the highest species turnover occurring in the Mediterranean region. Similarities between communities that were nearer each other (typically < 100 km) were weaker in shifting than in stable dunes, although the distance decay for sites that were further apart was similar in both habitats. Variation in species composition in shifting dunes was mainly explained by distance and climate, while in stable dunes the effect of climate was clearly dominant. The observed differences were relatively consistent across geographical regions.Main conclusionsDistinct processes structure the metacommunities in two dune habitats differentiated along the seashore–inland gradient. Communities of shifting dunes seem to be structured by an interplay of neutral or patch‐dynamic processes and to a lesser degree by species sorting. In contrast, communities of stable dunes are mainly governed by species sorting in response to climatic gradients. These results highlight the importance of differentiating habitats according to local ecological factors when analysing regional patterns in metacommunities.

Factors influencing the distribution of trematode larvae in blue mussels Mytilus edulis in the North Atlantic and Arctic Oceans

Blue mussels, Mytilus edulis, serve as second intermediate hosts for several trematode species, but little is known about the mechanisms underlying parasite infections in mussels. To reveal these mechanisms, the prevalence and intensity of trematode larvae (metacercariae in species of Gymnophallus, Himasthla and Renicola) were examined in blue mussels at 19 intertidal sites from the North Atlantic (Ireland, Iceland, Norway) to the Arctic Ocean (north-western Russia). Mussel samples were taken in 2005–2008. The impact of a number of environmental (maximal sea surface temperature, SSTmax) and biological factors (mussel age and density and the abundance of avian final hosts) on trematode infection was examined. Infection levels correlated with the interaction between local bird abundance and mussel age and density. They increased with mussel age but their dependence on mussel density and bird abundance varied among parasite genera. Prevalence and intensity increased with SSTmax for Renicola spp., but no relationship was found for Gymnophallus and Himasthla spp. The ambiguous effect of SSTmax is likely explained by the broad range of optimal temperatures for the normal functioning of trematode larvae (cercariae) infective for mussels and by the high dependence of the level of mussel infection on a combination of local ecological factors. High infection levels were observed even in localities with a low SSTmax. No mussels were infected in the most north-eastern population, probably due to extreme conditions in the Arctic intertidal preventing trematode transmission. Future warming of the Arctic may accelerate trematode transmission in this system.

Feather corticosterone levels on wintering grounds have no carry-over effects on breeding among three populations of great skuas (Stercorarius skua).

Environmental conditions encountered by migratory seabirds in their wintering areas can shape their fitness. However, the underlying physiological mechanisms remain largely unknown as birds are relatively inaccessible during winter. To assess physiological condition during this period, we measured corticosterone concentrations in winter-grown primary feathers of female great skuas (Stercorarius skua) from three breeding colonies (Bjørnøya, Iceland, Shetland) with wintering areas identified from characteristic stable isotope signatures. We subsequently compared winter feather corticosterone levels between three wintering areas (Africa, Europe and America). Among females breeding in 2009, we found significant differences in feather corticosterone levels between wintering areas. Surprisingly, levels were significantly higher in Africa despite seemingly better local ecological factors (based on lower foraging effort). Moreover, contrary to our predictions, females sharing the same wintering grounds showed significant differences in feather corticosterone levels depending on their colony of origin suggesting that some skuas could be using suboptimal wintering areas. Among females wintering in Africa, Shetland females showed feather corticosterone levels on average 22% lower than Bjørnøya and Iceland females. Finally, the lack of significant relationships between winter feather corticosterone levels and any of the breeding phenology traits does not support the hypothesis of potential carry-over effects of winter feather corticosterone. Yet, the fitness consequences of elevated feather corticosterone levels remain to be determined.

THE INTERPLAY BETWEEN LOCAL ECOLOGY, DIVERGENT SELECTION, AND GENETIC DRIFT IN POPULATION DIVERGENCE OF A SEXUALLY ANTAGONISTIC FEMALE TRAIT

Genetically polymorphic species offer the possibility to study maintenance of genetic variation and the potential role for genetic drift in population divergence. Indirect inference of the selection regimes operating on polymorphic traits can be achieved by comparing population divergence in neutral genetic markers with population divergence in trait frequencies. Such an approach could further be combined with ecological data to better understand agents of selection. Here, we infer the selective regimes acting on a polymorphic mating trait in an insect group; the dorsal structures (either rough or smooth) of female diving beetles. Our recent work suggests that the rough structures have a sexually antagonistic function in reducing male mating attempts. For two species (Dytiscus lapponicus and Graphoderus zonatus), we could not reject genetic drift as an explanation for population divergence in morph frequencies, whereas for the third (Hygrotus impressopunctatus) we found that divergent selection pulls morph frequencies apart across populations. Furthermore, population morph frequencies in H. impressopunctatus were significantly related to local bioclimatic factors, providing an additional line of evidence for local adaptation in this species. These data, therefore, suggest that local ecological factors and sexual conflict interact over larger spatial scales to shape population divergence in the polymorphism.

ForestMAS – A single tree based secondary succession model employing Ellenberg indicator values

Over recent decades farmland abandonment has affected large areas of the landscape. To better predict the changes associated with this process, we developed a secondary succession model based on Ellenberg indicator values describing the ecological niche of a tree along environmental gradients. These values are compared with local ecological factors dependent on terrain conditions. The terrain is represented by a Digital Terrain Model, where the local conditions are represented by a light availability model, climate data, soil properties, and a combination of a water flow model and average annual rainfall data. Each tree in our model is associated with its immediate circular ecological neighbourhood and is treated individually from the seedling stage through to its decay. Each year, tree heights, actual vigour, and neighbourhood radii were calculated. When two radii intersected, the vigour of both trees was compared. The weaker of the two became dominated, leading to stress-related mortality. When a tree reached the adult stage, it produced seeds that established new seedlings that competed for light and nutrition. To start the simulation, the initial amount of seed was planted on bare ground. It was possible to monitor the succession phases either visually or statistically. 3D tree models were used to visualize a tree at any age, generating realistic landscape images useful for demonstrating long-term changes in the cultural landscape to non-experts. The results were compared with those from previous field studies in various areas of Slovenia. Apart from predicting landscape changes after farmland abandonment, the model can be used for forecasting the regeneration process after clearcutting or natural disasters.

Erratum to: The interacting effects of temperature, ground disturbance, and herbivory on seedling establishment: implications for treeline advance with climate warming

Thermal control of treeline position is mediated by local environmental and ecological factors, making trends in treeline migration difficult to extrapolate geographically. We investigated the ecological dynamics of conifer establishment at treeline in the Mealy Mountains (Labrador, Canada) and the potential for its expansion with climate warming. Available seedbed and tree seedling emergence in the treeline ecotone were monitored, and seeds and seedlings of Picea mariana were planted along an elevational gradient from open-canopy forest through tree islands to alpine tundra. Experimental treatments included passive warming of daytime air, ground disturbance, and vertebrate herbivore exclosures. Responses in seed germination and seedling growth, damage, and mortality were monitored over two growing seasons, and re-surveyed after 5 years. While no tree seedlings were observed growing naturally above the treeline, planted seeds were able to germinate, develop and overwinter, and persist for 4 years in all habitats examined. Disturbance of the seedbed was important for seedling emergence in the forest and tree islands. While temperature enhancement alone had little impact on emergence, even moderate temperature increases had significantly disproportionate effects on emergence of seedlings in the alpine habitat when combined with soil disturbance, indicating that future climate warming could lead to treeline advance if viable seed and suitable substrate for recruitment are available. The positive effect of excluding herbivores suggests that herbivory may be an important filter modifying future species distribution. While seedbed conditions and herbivory would control the rate of individual species advance, the results indicate potential upslope migration of the treeline in the Mealy Mountains, with consequent loss of alpine ecosystems.

Seed dormancy and germination in three Crocus ser. Verni species (Iridaceae): implications for evolution of dormancy within the genus

The aim of this work was to examine whether seed ecophysiological traits in three closely related Crocus species were associated with ecological niche differentiation and species divergence. Seeds of the temperate tetraploid cytotype of Crocus neapolitanus, the sub-Mediterranean C.etruscus and the Mediterranean C.ilvensis were placed either on agar in the laboratory under different periods of simulated seasonal conditions or in nylon mesh bags buried outdoors to examine embryo growth, radicle and shoot emergence. In agreement with the phenology observed outdoors, in the laboratory embryos required a cool temperature (ca. 10°C) to grow to full size (embryo length:seed length, E:S ratio ca. 0.75) but only after seeds received a warm stratification; radicle emergence then followed immediately (November). Shoot emergence is a temporally separated phase (March) that was promoted by cold stratification in C.neapolitanus while in the other two species this time lag was attributed to a slow continuous developmental process. These species have similar embryo growth and radicle phenology but differ in their degree of epicotyl dormancy, which is related to the length of local winter. Conclusions from laboratory experiments that only consider root emergence could be misleading; evaluating the phenology of both root and shoot emergence should be considered in order to demonstrate ecologically meaningful differences in germination behaviour and to develop effective propagation protocols. Although these taxa resulted from recent speciation processes, the outcomes suggest an early onset of adaptation to local ecological factors and that phylogeny may represent a significant constraint in the evolution and expression of seed traits in Crocus.

Ecological and Environmental State of the North-western Algerian Coast

The present study is an analysis of the evolution of the ecological environment natural habitats on a number of years framed in three decades. It is interested in the coastal ecosystem (ecosystem, habitat nature, and Posidonia) in Oran (Algeria). The research activity has exactly been guided in the Department of Biology, Faculty of Life Sciences and Nature, Oran University, the North-West of Algeria 2012-2013. The methods used in the study are largely based on several environmental and ecological data acquired during the last thirty years, supplemented by field research and personal observations (dives, offshore work, surveys along the coast). Then the data were collected to arrive at the proposal of a scalable representation of the band of the Oran coast state. During the last thirty years the western Algerian coast has experienced a loss of space and of species (Macta, Kristel, Ain El-Turk Village), and urban expansion has occurred mainly along the coast. The touristic, industrial, and residential development has not taken environmental quality into consideration and has largely contributed to its degradation and to the pollution of the marine and coastal local ecosystem (Targa and El Maleh zone). Today the local environmental and ecological factors are displayed and their variability is relatively identified. It is just as critical to generate studies and efforts to protect the coastal species and habitats, as well as oversight and ongoing discussions of the existing rich ecosystem. Also, laws in favor of marine and coastal resource protection must be applied.

Conservation value of secondary forest habitats for endemic birds, a perspective from two widely separated tropical ecosystems

Tropical secondary forests are increasingly widespread, but their potential for conserving endemic birds remains unclear. Previous studies report different results; however all have been restricted to geographically discreet locations. This is important as different ecosystems are influenced by different external factors, possibly influencing conservation potential. Here we use consistent survey methods to examine how endemic bird richness varies between primary and secondary forest habitats in two widely separated tropical ecosystems, providing a more global context for evaluating the conservation value of secondary forests. Research was completed in Lambusango Forest Reserve (LFR) on Buton Island, Sulawesi, and Cusuco National Park (CNP), a Honduran cloud forest reserve. Bird communities in both forests were surveyed using 50 m radius point counts. Vulnerability assessments based on ecological theory on avifaunal assemblages were then conducted, which suggested endemics in LFR to be more susceptible to disturbance than those in CNP. Contrary to the results from our vulnerability assessments, endemics in CNP were less tolerant of moderate habitat modification than those in LFR. Richness of Mesoamerican endemics per study site declined significantly between core zone forest (6.34 ± 0.81) and more degraded forest in the boundary zone (3.86 ± 0.69). Richness of Wallacean endemics was similar in primary (4.89 ± 1.68) and disturbed secondary forest (4.52 ± 1.62). We recommend considering local and regional biogeographical and ecological factors when determining the conservation value of secondary forests, and suggest examples of potential importance, including differential community richness, influence of figs and human settlement patterns.

Stable carbon isotopes of C3 plant resins and ambers record changes in atmospheric oxygen since the Triassic

Estimating the partial pressure of atmospheric oxygen (pO2) in the geological past has been challenging because of the lack of reliable proxies. Here we develop a technique to estimate paleo-pO2 using the stable carbon isotope composition (δ13C) of plant resins—including amber, copal, and resinite—from a wide range of localities and ages (Triassic to modern). Plant resins are particularly suitable as proxies because their highly cross-linked terpenoid structures allow the preservation of pristine δ13C signatures over geological timescales. The distribution of δ13C values of modern resins (n=126) indicates that (a) resin-producing plant families generally have a similar fractionation behavior during resin biosynthesis, and (b) the fractionation observed in resins is similar to that of bulk plant matter. Resins exhibit a natural variability in δ13C of around 8‰ (δ13C range: −31‰ to −23‰, mean: −27‰), which is caused by local environmental and ecological factors (e.g., water availability, water composition, light exposure, temperature, nutrient availability). To minimize the effects of local conditions and to determine long-term changes in the δ13C of resins, we used mean δ13C values (δ13Cmeanresin) for each geological resin deposit. Fossil resins (n=412) are generally enriched in 13C compared to their modern counterparts, with shifts in δ13Cmeanresin of up to 6‰. These isotopic shifts follow distinctive trends through time, which are unrelated to post-depositional processes including polymerization and diagenesis. The most enriched fossil resin samples, with a δ13Cmeanresin between −22‰ and −21‰, formed during the Triassic, the mid-Cretaceous, and the early Eocene. Experimental evidence and theoretical considerations suggest that neither change in pCO2 nor in the δ13C of atmospheric CO2 can account for the observed shifts in δ13Cmeanresin. The fractionation of 13C in resin-producing plants (Δ13C), instead, is primarily influenced by atmospheric pO2, with more fractionation occurring at higher pO2. The enriched δ13Cmeanresin values suggest that atmospheric pO2 during most of the Mesozoic and Cenozoic was considerably lower (pO2=10–20%) than today (pO2=21%). In addition, a correlation between the δ13Cmeanresin and the marine δ18O record implies that pO2, pCO2, and global temperatures were inversely linked, which suggests that intervals of low pO2 were generally accompanied by high pCO2 and elevated global temperatures. Intervals with the lowest inferred pO2, including the mid-Cretaceous and the early Eocene, were preceded by large-scale volcanism during the emplacement of large igneous provinces (LIPs). This suggests that the influx of mantle-derived volcanic CO2 triggered an initial phase of warming, which led to an increase in oxidative weathering, thereby further increasing greenhouse forcing. This process resulted in the rapid decline of atmospheric pO2 during the mid-Cretaceous and the early Eocene greenhouse periods. After the cessation in LIP volcanism and the decrease in oxidative weathering rates, atmospheric pO2 levels continuously increased over tens of millions of years, whereas CO2 levels and temperatures continuously declined. These findings suggest that atmospheric pO2 had a considerable impact on the evolution of the climate on Earth, and that the δ13C of fossil resins can be used as a novel tool to assess the changes of atmospheric compositions since the emergence of resin-producing plants in the Paleozoic.

Morphological asymmetry of insular freshwater populations of threespine stickleback

Fluctuating asymmetry (FA), random deviations from perfect symmetry in a bilateral organism, has been widely used as a proxy for developmental instability in stressed populations. In order to test the utility of FA of resident freshwater threespine stickleback (Gasterosteus aculeatus) as a biomonitoring tool for contaminated sites, we compared levels of asymmetry of seven morphological traits of threespine stickleback collected from lakes at three islands with a history of military contamination and three islands with no military history, in the Aleutian Archipelago, Alaska. Traits examined include eye diameter, operculum width, pectoral fin ray number, pectoral fin width, lateral plate number, lateral plate length, and pelvic spine length. All morphometric traits demonstrated some degree of FA or directional asymmetry (DA), but the military history of a lake was not a predictor of the degree or type of asymmetry. Overall, the patterns of asymmetry were similar for all traits, irrespective of military contamination at a lake. Our results demonstrate that the suite of threespine stickleback traits measured are not suitable for examination of FA as a proxy for aquatic pollution in this region. DA also does not appear to be suitable as an indicator of aquatic pollution, but may instead be driven by local ecological factors such as predation.

The forgotten resource: Community perspectives on conservation and well - being in Zahamena National Park, Madagascar

This research examines local perceptions of social well - being in two forest - dependent communities near Zahamena National Park (ZNP), Madagascar. Key informant interviews were conducted to observe how local context, including community and ecological factors, influenced perceptions of social well - being. Overall, residents expressed a broad sense of decreased wellbeing as local forest resource access changed following the creation of ZNP. While one community was more dependent on forest and non - timber forest products for their livelihood, both communities believed lack of access to the park and its resources negatively affected local social well - being. Further, both communities felt ZNP provided few benefits to local residents. In addition, informants alluded to a sense of distrust of conservation managers and believed their needs and concerns were neither heard nor addressed by current conservation programs. Such data confirm people living in rural communities adjacent to protected areas have limited impact on conservation policies and initiatives on the island. Implications of this research suggest a reassessment of institutional conservation policy and practices to reflect locally held social traditions and community beliefs about conservation.

Geographical and ecological differentiation of Fagus forest vegetation in SE Europe

AbstractQuestionsWhat is the main syntaxonomical pattern within beech forests in SE Europe? What macroecological and ecological factors distinguish these forests?LocationSE Europe: Balkan Peninsula, from the SE Alps in Slovenia, through Croatia, Bosnia and Herzegovina, Serbia, Montenegro and the Republic of Macedonia to N and NE Greece and Bulgaria, covering ca. 400 000 km2 over a length of 1000 km.MethodsWith a view to differentiating beech and beech–fir forests, a data set of 5952 published and unpublished phytosociological relevés were surveyed. After stratification, 997 relevés remained. Cluster analysis of the data set was used to calculate diagnostic species for each cluster. Ecological indicator values (EIV) were used to estimate ecological conditions. Average EIV, altitude, latitude and longitude for relevés of each cluster were plotted in a detrended correspondence analysis (DCA) diagram for ecological interpretation of clusters and relationships between clusters. Correlations between DCA relevé scores and explanatory variables (EIV, portion of life forms and chorotypes, altitude, latitude and longitude) were subsequently calculated.ResultsCluster analysis divided mesophilous beech forests of SE Europe into two major clusters. Beech forests can therefore be classified into two alliances, Aremonio‐Fagion and Fagion moesiacae. Further division revealed seven beech and beech–fir forest types, which we interpreted geographically and ecologically. A significant increase in the proportion of chamaephytes, hemicryptophytes and therophytes was detected along the main macroecological gradient towards the S and E. At the same time, the proportion of geophytes and phanerophytes significantly decreased in the same direction. There was also a significant increase in the proportion of Stenomediterranean, Eurymediterranean, Mediterranean‐Montane, and Eurasian species, while Boreal species, as expected, decreased toward the southeast. The main differentiation of beech forests in SE Europe is due to macroecological factors (macro‐climatic and historical development of vegetation), whereas local ecological factors (particularly temperature and moisture) are reflected in the differentiation of sub‐alliances.ConclusionsOur study confirmed two major groups of beech forests in the research area, which could be classified into two alliances. It also revealed that there is not just an altitudinal distribution of beech forests in the SE part of the research area, but also structural and functional changes of communities as a result of the altitudinal limitation of beech forests and changed macroclimatic factors.

An abrupt ecosystem change in Lake Beloye, southern Western Siberia: Palaeoclimate versus local environment

Sediment structure, rock-magnetic and bio-geochemical records obtained from sapropel core samples in Lake Beloye, southern Western Siberia, indicate an abrupt ecosystem change at 3.4 calibrated ka BP. The lake changed from eutrophic to oligotrophic, its vegetation — from carbon-fixing macrophytic angiosperms to calcium-fixing macrophytic algae and angiosperms, and, as a result, the type of sedimentation shifted from peaty sapropel to carbonate-rich sapropel. Those changes could be induced by climate, which was warmer and wetter before 3.4ka BP and cooler and drier after this. Nevertheless, our data show that those ecosystem changes occurred when the lake became shallower to get about 1m depth and started to freeze to the bottom in winter time. The full freezing of the lake led to the deposition of carbonates, which resulted in: i) death of carbon-utilizing macrophytic angiosperms; and ii) winter precipitation of calcium carbonate. In summer, additional portions of Ca2+ and HCO3− ions come into the lake from the surrounding CaCO3 rich loess sediments with ground water. The Beloye Lake thus represents an example of interrelated regional climatic and local ecological factors, which combination resulted in the 3.4cal. ka BP dramatic change of its ecosystem.