How to ensure threatened species monitoring leads to threatened species conservation

Monitoring is essential for effective conservation and management of threatened species and ecological communities. However, more often than not, threatened species monitoring is poorly implemented, meaning that conservation decisions are not informed by the best available knowledge. We outline challenges and provide best‐practice guidelines for threatened species monitoring, informed by the diverse perspectives of 26 conservation managers and scientists from a range of organisations with expertise across Australian species and ecosystems. Our collective expertise synthesised five key principles that aim to enhance the design, implementation and outcomes of threatened species monitoring. These principles are (i) integrate monitoring with management; (ii) design fit‐for‐purpose monitoring programs; (iii) engage people and organisations; (iv) ensure good data management; and (v) communicate the value of monitoring. We describe how to incorporate these principles into existing frameworks to improve current and future monitoring programs. Effective monitoring is essential to inform appropriate management and enable better conservation outcomes for our most vulnerable species and ecological communities.     

How selection structures species abundance distributions

How do species divide resources to produce the characteristic species abundance distributions seen in nature? One way to resolve this problem is to examine how the biomass (or capacity) of the spatial guilds that combine to produce an abundance distribution is allocated among species. Here we argue that selection on body size varies across guilds occupying spatially distinct habitats. Using an exceptionally well-characterized estuarine fish community, we show that biomass is concentrated in large bodied species in guilds where habitat structure provides protection from predators, but not in those guilds associated with open habitats and where safety in numbers is a mechanism for reducing predation risk. We further demonstrate that while there is temporal turnover in the abundances and identities of species that comprise these guilds, guild rank order is conserved across our 30-year time series. These results demonstrate that ecological communities are not randomly assembled but can be decomposed into guilds where capacity is predictably allocated among species.     

Convergence to stationary distributions in two-species stochastic competition models

Two sets of sufficient conditions are given for convergence to stationary distributions, for some general models of two species competing in a randomly varying environment. The models are nonlinear stochastic difference equations which define Markov chains. One set of sufficient conditions involves strong continuity and -irreducibility of the transition probability for the chain. The second set has a much weaker irreducibility condition, but is only applicable to monotonic models. The results are applied to a stochastic two-species Ricker model, and to Chesson's lottery model with vacant space, to illustrate how the assumptions can be checked in specific models.     

Optimizing ventricular fibers: uniform strain or stress,but not ATP consumption,leads to high efficiency

The aim of this study was to investigate the influence of fiber orientation in the left ventricular (LV) wall on the ejection fraction, efficiency, and heterogeneity of the distributions of developed fiber stress, strain and ATP consumption. A finite element model of LV mechanics was used with active properties of the cardiac muscle described by the Huxley-type cross-bridge model. The computed variances of sarcomere length (SL(var)), developed stress (DS(var)), and ATP consumption (ATP(var)) have several minima at different transmural courses of helix fiber angle. We identified only one region in the used design space with high ejection fraction, high efficiency of the LV and relatively small SL(var), DS(var), and ATP(var). This region corresponds to the physiological distribution of the helix fiber angle in the LV wall. Transmural fiber angle can be predicted by minimizing SL(var) and DS(var), but not ATP(var). If ATP(var) was minimized, then the transverse fiber angle was considerably underestimated. The results suggest that ATP consumption distribution is not regulating the fiber orientation in the heart.     

Consequences of competition on the time budgets,growth and distributions of three species of terrestrial slugs

Summary The behavioural time budgets of two non-aggressive slugs and one aggreessive species were evaluated in monocultures or in 2-way combinations in field cages. The seasonal time budgets ofL. maximus, A. ater andA. columbianus in monoculture were remarkably similar despite their strong differences in physiological resource allocation. Similarity in physical design and resource utilization appeared to be more important determinants of behaviour. The time budgets showed distinct seasonal patterns associated with underlying physiological demands for reserve accumulation, sperm acquisition and oviposition.A. ater andL. maximus displayed a definite dispersal phase associated with femalephase maturation. In combination,A. ater andA. columbianus had no detectable effect on one another’s time budgets.L. maximus disrupted nearly every category of behaviour in these non-aggressive species, but its own time budget was not significantly different in the monoculture or in the two combinations, except for minor effects on resting and sexual behaviour.L. maximus appeared to be adapted to maximize behavioural disturbance of interspecific competitors while minimizing intraspecific effects.     

Female mate preference to maximize paternal care. II. Female competition leads to monogamy

ABSTRACT A two-step game model of female mate preference and paternal care is examined, with a particular focus on the case of two females and two males. In a mating season, females choose their mates, and in the following breeding season males invest in paternal care, knowing the likelihood of their paternity in chicks. If parental ability is the same between individuals of each sex, the evolutionarily stable mating pattern is always monogamy. If females differ in fecundity and males differ in paternal care capacity, monogamy with assortative mating is likely to be evolutionarily stable. If the male cost function increases at a strongly accelerating rate, however, polyandry is evolutionarily stable when the difference of female fecundity is very large, but the game may have no evolutionarily stable state when the difference of female fecundity is small. The care graph (in which females are connected to males giving paternal care to their chicks) is often much simpler than the mating graph (in which females are connected to males they accepted). To be exact, no "loop" should be included in the evolutionarily stable care graph for the general case of n females and m males. This prediction is in accord with the observed prevalence of social monogamy in spite of genetic promiscuity among altricial birds.     

Warming leads to higher species turnover in a coastal ecosystem

The responses of ecological communities and ecosystems to increased rates of environmental change will be strongly influenced by variation in the diversity of community composition. Yet, our understanding of how diversity is affected by rising temperatures is inconclusive and mainly based on indirect evidence or short‐term experiments. In our study, we analyse the diversity and species turnover of benthic epilithic communities within the thermal flume of a nuclear power plant at the Swedish coast. This flume covers the range of predicted future temperature rises. Species composition was significantly different between control sites and sites with higher temperatures. We found that temperature had little effect on the number of species in three functional groups (macroinvertebrates, benthic diatoms, and macrophytes, which here comprise multicellular algae and macroscopic colonies of unicellular algae and cyanobacteria), neither at single sampling dates nor summed for the entire observation year. However, species turnover significantly increased with increasing temperature for diatoms, macrophytes and invertebrates. Different temperature regimes resulted in significantly different species composition and indicator species. Thus, increasing temperatures in the thermal flume increased temporal beta‐diversity and decreased compositional stability of communities, although observed richness did not change at any point in time. We highlight the need to investigate the consequences of such declines in compositional stability for functional stability of ecosystem processes.     

How species respond to multiple extinction threats

It is well established that different species vary in their vulnerability to extinction risk and that species biology can underpin much of this variation. By contrast, very little is known about how the same species responds to different threat processes. The purpose of this paper is therefore twofold: to examine the extent to which a species' vulnerability to different types of threat might covary and to explore the biological traits that are associated with threat-specific responses. We use an objective and quantitative measure of local extinction risk to show that vulnerability to local population decline in primates varies substantially among species and between threat types. Our results show that a species' response to one threat type does not predict its response to others. Multivariate analyses also suggest that different mechanisms of decline are associated with each type of threat, since different biological traits are correlated with each threat-specific response. Primate species at risk from forestry tend to exhibit low ecological flexibility, while those species vulnerable to agriculture tend to live in the canopy and eat low-fruit diets; in further contrast, primates at risk from hunting tend to exhibit large body size. Our analyses therefore indicate that a species' vulnerability to local extinction can be highly variable and is likely to depend on both threat type and biology.     

Wasp behavior leads to uniform parasitism of a host available only a few hours per year

The parasitoid wasp, Hyposoter horticola, parasitizes a nearlyfixed fraction of its host butterfly larvae within a host metapopulationof 300–500 local populations in a 50 x 70-km area. Weshow, through laboratory observation, that the wasp lays eggsin fully developed larvae that have not yet hatched from theegg, constraining the period of host vulnerability to severalhours out of the host's one year lifecycle. The parasitoid achievesa persistent high rate of parasitism over the entire host rangedespite the extremely limited period of host vulnerability aswell as a high rate of host population extinctions and colonizationsof new habitat patches every year. It does this in part by beingextremely mobile. In addition, we show by using a field experimentand observation of marked wasps foraging for hosts in naturalpopulations, that the wasp finds virtually all host egg clustersin the weeks before the hosts become vulnerable to parasitism,and then later returns to parasitize them. By locating the hostsbefore their vulnerability, the wasp extends the time availablefor searching from hours to weeks. After parasitizing aboutone-third of the larvae in a host cluster the wasp stops, apparentlyleaving a mark that deters further parasitism by other individuals.The result of this novel combination of mobility and local foragingbehavior is a stable population size despite an unstable hostthat is vulnerable during about one thousandth of its lifecycle.     

Germination responses to abiotic stress shape species distributions on coastal dunes

Plant species occupy distinct zones on coastal dunes, but the mechanisms limiting their distributions have not been fully explained. We combined field surveys of plant distributions and abiotic conditions with controlled germination experiments to assess the contribution of germination requirements to plant zonation. Species presence and abiotic conditions were measured in ten transects across the barrier dune at Waquoit Bay, Massachusetts. Germinating seeds of six species were exposed to four fully crossed treatments: pre-treatment (soaked in fresh water, soaked in salt water, or not soaked), temperature (low, moderate, or high), soil salinity (none, moderate, or high), and light (full light, shade, dark). Species distributions in the field were affected by both distance from the shore and presence of dominant shrubs. Germination tolerance of soil salinity reflected species zonation: species found on the front slope of the dune tolerated salinity, while germination of other species was limited by salinity alone or by salinity in combination with high temperature. Shrubs reduced soil surface temperature and decreased light, but these conditions had limited effects on germination. These results indicate that limitations to germination can contribute to explaining species distributions on coastal dunes.     

Relating species abundance distributions to species-area curves in two Mediterranean-type shrublands

Abstract. Based on both theoretical and empirical studies there is evidence that different species abundance distributions underlie different species‐area relationships. Here I show that Australian and Californian shrubland communities (at the scale from 1 to 1000 m²) exhibit different species‐area relationships and different species abundance patterns. The species‐area relationship in Australian heathlands best fits an exponential model and species abundance (based on both density and cover) follows a narrow log normal distribution. In contrast, the species‐area relationship in Californian shrublands is best fit with the power model and, although species abundance appears to fit a log normal distribution, the distribution is much broader than in Australian heathlands. I hypothesize that the primary driver of these differences is the abundance of small‐stature annual species in California and the lack of annuals in Australian heathlands. Species‐area is best fit by an exponential model in Australian heathlands because the bulk of the species are common and thus the species‐area curves initially rise rapidly between 1 and 100 m². Annuals in Californian shrublands generate very broad species abundance distributions with many uncommon or rare species. The power function is a better model in these communities because richness increases slowly from 1 to 100 m² but more rapidly between 100 and 1000 m² due to the abundance of rare or uncommon species that are more likely to be encountered at coarser spatial scales. The implications of this study are that both the exponential and power function models are legitimate representations of species‐area relationships in different plant communities. Also, structural differences in community organization, arising from different species abundance distributions, may lead to different species‐area curves, and this may be tied to patterns of life form distribution.     

Extracellular acidification leads to reactive oxygene species formation in rat brain synaptosomes

Formation of reactive oxygen species in rat brain synaptosomes was studied using DCFDA fluorescent dye at lowered extracellular pH. It has been shown that decrease in pH value from 7.4 to 7.0 and up to 6.0 leads to increase of fluorescence that is indicative of oxidative stress. The effect is observed regardless of whether Ca ions are present in incubation medium or no. Acidification of the incubation medium induces quenching of fluorescence of previously oxidized form of the dye in experiments without synaptosomes This evidences that increase of dye fluorescence is really associated with reactive oxygen species accumulation. Thus, it has been demonstrated that pH declined up to 7.0 in the incubation medium is sufficient to induce the formation of reactive oxygen species in synaptosomes.     

Hybridization leads to host-use divergence in a polyphagous butterfly sibling species pair

Climate warming has lead to increased genetic introgression across a narrow hybrid zone separating the eastern and Canadian tiger swallowtails (Papilio glaucus and Papilio canadensis). This situation has led to the formation of an allochronically separated hybrid population with a delayed emerging phenotype or “late flight”. Here, we assess how the recombination of the parental genomes that lead to this phenotype may have facilitated another major ecological shift, host-use divergence. We first contrast the ovipositional profiles of the late flight population to that of the parental species P. glaucus and P. canadensis. Subsequently we contrast the larval survival and growth of the late flight, a P. canadensis and a P. glaucus population, and a population from the northern edge of the hybrid zone on five hosts. Our results indicate that the ovipositional preference of this hybrid swarm is identical to that of the introgressing parental species, P. glaucus. Due to the absence of the preferred hosts of P. glaucus (Liriodendron tulipifera L. and Ptelea trifoliata L.) where the late flight occurs, this ovipositional pattern implies a functional specialization onto a secondary host of both parental species, Fraxinus americana L. In contrast, the larval host-use abilities represent a mixture of P. glaucus and P. canadensis, indicating divergence in larval host-use abilities has not taken place. However, high genetic variability (genetic coefficient of variation) is present for growth on F. americana in the late flight hybrid swarm and tradeoffs for larval performance on the preferred hosts of the parental species are evident; indicating a strong potential for future specialization in larval host-use abilities. This current scenario represents an instance where a shift in a major ecological trait, host use, is likely occurring as a byproduct of a shift in an unrelated trait (delayed emergence) leading to partial reproductive isolation.     

Intermittent 20-HZ-photic stimulation leads to a uniform reduction of alpha-global field power in healthy volunteers.

19-channel-EEGs were recorded from scalp surface of 30 healthy subjects (16m, 14f, mean age: 34 ys, SD: 11.7 ys) at rest and under IPS (Intermittent Photic Stimulation) at rates of 5, 10 and 20 Hertz (Hz). Digitalized data underwent spectral analysis with fast fourier transfomation (FFT) yielding the basis for the computation of global field power (GFP). For quantification GFP values in the frequency ranges of 5, 10 and 20 Hz at rest were divided by the corresponding data gained under IPS. While ratios from PDE data showed no stable parameter due to high interindividual variability, ratios of alpha-power turned out to be uniform in all subjects: IPS at 20 Hz always led to a suppression of alpha-power. Dividing alpha-GFP at rest by alpha-GFP under 20-Hz IPS thus resulted in a ratio < 1. We conclude that ratios from GFP data are a stable diagnostic paradigma.     

Limits to elevational distributions in two species of emberizine finches: disentangling the role of interspecific competition, autoecology, and geographic variation in the environment

When species' elevational ranges are wider where putative competitors are absent, researchers have concluded that interspecific competition influences elevational distributions. This overlooks the distinction between factors that limit distributions directly and factors that only influence organisms indirectly through covarying regulators or resources. Because elevation affects organisms indirectly, testing whether competition influences elevational ranges relies on the heretofore untested assumption that the relationship between elevation and factors influencing organisms directly is similar across geography. Focusing on Buarremon brush-finches (Aves: Emberizidae), a group in which distributions represent one of the best examples of the potential role of competition limiting elevational ranges, we show that when distributions are compared along axes of climatic variation, some patterns of elevational range variation do appear to be consistent with predictions of the hypothesis that release from competition underlies expanded elevational ranges in allopatry. However, other patterns of expanded elevational ranges in the absence of putative competitors are better explained by hypothesis related to species' autoecology and geographic variation in the environment. This latter finding cautions against using elevation uncritically as a dimension of ecological niches, and suggests that classical examples of interspecific competition may need re-evaluation.     

Biomass responses to intraspecific competition differ between wild species and CO2

Aims: How growth of wild and crop species responds to global environmentalperturbations has both ecological and agricultural significancein a changing world. The primary aim of this synthesis was toquantitatively assess the interactive effects of intraspecificcompetition and elevated CO₂ on biomass production in herbaceousspecies. Methods: Using meta-analytical techniques, we synthesized data from publicationsbefore 2006 that reported biomass responses to elevated CO₂in 321 herbaceous species grown in isolation or in competitionwith con-specific individuals. Important findings: Intraspecific competition differentially modified biomass responsesto elevated CO₂ in wild and crop species. For example, competitionreduced CO₂ stimulation of total biomass (W_T) from 27 to 23%in wild species, but by a much greater magnitude, i.e., from43 to 32% in crops. Competition had no effect on responses ofeither above- (W_AG) or below-ground (W_BG) biomass to elevatedCO₂ in wild species, but significantly diminished CO₂ enhancementof W_AG, although not of W_BG, in crops. Considerable variationswere found among functional groups in the modification of growthresponses to elevated CO₂ by intraspecific competition, whichexerted greater depression on CO₂ enhancement in C₃ than inC₄ species and in non-legumes than in legumes. Elevated CO₂affected leaf and stem growth of individually grown C₃ graminoidsand forbs similarly, but increased leaf growth only in C₄ graminoidsand stem growth only in C₄ forbs. Results from this synthesisdemonstrated that intraspecific competition differentially affectedgrowth responses to elevated CO₂ in wild and crop species. Thewild–crop species differences will have important implicationsfor understanding primary production by herbaceous species inboth natural and agricultural ecosystems in the future whenatmospheric CO₂ is significantly higher than the current level.