Are behavioral differences among wild chimpanzee communities genetic or cultural? An assessment using tool‐use data and phylogenetic methods

Over the last 30 years it has become increasingly apparent that there are many behavioral differences among wild communities of Pan troglodytes. Some researchers argue these differences are a consequence of the behaviors being socially learned, and thus may be considered cultural. Others contend that the available evidence is too weak to discount the alternative possibility that the behaviors are genetically determined. Previous phylogenetic analyses of chimpanzee behavior have not supported the predictions of the genetic hypothesis. However, the results of these studies are potentially problematic because the behavioral sample employed did not include communities from central Africa. Here, we present the results of a study designed to address this shortcoming. We carried out cladistic analyses of presence/absence data pertaining to 19 tool‐use behaviors in 10 different P. troglodytes communities plus an outgroup (P. paniscus). Genetic data indicate that chimpanzee communities in West Africa are well differentiated from those in eastern and central Africa, while the latter are not reciprocally monophyletic. Thus, we predicted that if the genetic hypothesis is correct, the tool‐use data should mirror the genetic data in terms of structure. The three measures of phylogenetic structure we employed (the Retention Index, the bootstrap, and the Permutation Tail Probability Test) did not support the genetic hypothesis. They were all lower when all 10 communities were included than when the three western African communities are excluded. Hence, our study refutes the genetic hypothesis and provides further evidence that patterns of behavior in chimpanzees are the product of social learning and therefore meet the main condition for culture. Am J Phys Anthropol, 2010. © 2010 Wiley‐Liss, Inc.     

Do lizard communities partition the trophic niche? A worldwide meta‐analysis using null models

Lizards have been widely used as model organisms in community ecology over the past 30 years. I have reviewed more than 50 studies from the literature on the community ecology of lizards worldwide, with a focus on studies from 1990–2007. I determined if there is support for the hypotheses that many lizard communities 1) are non‐randomly organized along the trophic niche dimension, and 2) partition the available food resource to minimize interspecific competition. I used data on number of prey items and percentage of prey volume, to calculate dietary overlap among species. I compared true datasets to randomly generate new datasets produced by 3×10⁴ Monte Carlo permutations using two algorithms (RA2 and RA3). The great majority (more than 80%) of the communities were randomly organized along the trophic niche dimension using RA2 or RA3; the frequency of occurrence of detecting a non‐random structure in lizard community dietary studies did not differ significantly between datasets based on either number of prey items or prey volume. Thus, lizard communities usually do not partition the trophic niche axis. Concerning the number of prey items, logistic regression models showed that the presence of a structure in the dataset did not depend on number of species, method employed to obtain dietary data, matrix size, or location (continent), but instead significantly depended on whether a community was tropical. Concerning prey volume, presence of a structure in the dataset also did not depend on number of species, method employed to obtain dietary data, and tropical vs non‐tropical origin, but was marginally dependent on continent (South America was favoured for identifying a structure in the dataset) and matrix size. In general, a structure in the dataset was more often uncovered by using RA2 than RA3. Overall, I conclude that 1) lizard communities are unlikely to partition available food resources, and 2) as the method for identifying dietary items does not allow for accurate prey identification (at least at the genus level), there is a risk of obtaining false null results about community structure. This is because structure along the trophic niche axis is genuinely rare in lizards and also because inappropriate methods may erroneously lead to this conclusion. Therefore, conclusions from studies utilizing stomach dissection as a source of diet data (still common in the literature) should be cautiously considered for ethical reasons and because it is difficult to find any difference between stomach‐dissection and fecal‐pellet data when assessing the presence of a structure in datasets. My data also showed there are minor differences in the probability of detecting a structure in datasets using prey item number or prey volume data for lizards. The biases, both statistical and biological, associated with this meta‐analysis are discussed.     

Spatial and seasonal variability of macroinvertebrate metrics: Do macroinvertebrate communities track river health?

The present study analyses the relationships of a set of 19 macroinvertebrate community metrics in relation to hydromorphological and water quality stress gradients in the Pas river basin, Northern Spain. Moreover, this study also aims to identify the most sensible season for biomonitoring this temperate Atlantic basin by means of macroinvertebrate communities. Thus, macroinvertebrate communities were analysed, along with the physicochemical characteristics of water in January, April, August and November 2005, in 9 sites. Hydromorphological conditions were evaluated using the Hydrogeomorphologic Index and by quantifying the percentage of reinforced banks, the number of low-head dams and their distance to each study site. Hydromorphological and water quality stress gradients were determined by means of two independent Principal Component Analysis. Thus, we obtained two water quality stress gradients, indicating organic pollution and watershed runoff, respectively, and a hydromorphological stress gradient. Macroinvertebrate metrics correlated better with the hydromorphological and the organic pollution stress gradients during the stable flow season, probably because of the homogenisation of water and hydraulic characteristics in the high flow season. On the other hand, relationships between macroinvertebrate metrics and watershed runoff stress gradient seem to be more dominated by hydraulic conditions than by water quality characteristics. LIFE index and the ICMi were the macroinvertebrate metrics that best correlated with the hydromorphological stress gradient, while EPTt, EPt, IBMWP, ASPT, LIFE, AsMet, Rhet, NoIns% and MACh% were well correlated with the organic pollution stress gradient in the low flow period. EPTt, EPt, ASPT, Rhet, and AsMet did not show significant seasonal differences and, thus, they are recommended as appropriate metrics to integrate biomonitoring results from different seasons in temperate European Atlantic rivers. Finally, autumn seems to be the best season to sample macroinvertebrate communities in this temperate Atlantic basin for biomonitoring purposes, and might be also the case for other similar European rivers.     

Do phytoplankton communities evolve through a self-regulatory abundance–diversity relationship?

A small group of phytoplankton species that produce toxic or allelopathic chemicals has a significant effect on plankton dynamics in marine ecosystems. The species of non-toxic phytoplankton, which are large in number, are affected by the toxin-allelopathy of those species. By analysis of the abundance data of marine phytoplankton collected from the North-West coast of the Bay of Bengal, an empirical relationship between the abundance of the potential toxin-producing species and the species diversity of the non-toxic phytoplankton is formulated. A change-point analysis demonstrates that the diversity of non-toxic phytoplankton increases with the increase of toxic species up to a certain level. However, for a massive increase of the toxin-producing species the diversity of phytoplankton at species level reduces gradually. Following the results, a deterministic relationship between the abundance of toxic phytoplankton and the diversity of non-toxic phytoplankton is developed. The abundance-diversity relationship develops a unimodal pathway through which the abundance of toxic species regulates the diversity of phytoplankton. These results contribute to the current understanding of the coexistence and biodiversity of phytoplankton, the top-down vs. bottom-up debate, and to that of abundance-diversity relationship in marine ecosystems.     

Do changes in rainfall patterns affect semiarid annual plant communities?

Question: Climate change models forecast a reduction in annual precipitation and more extreme events (less rainy days and longer drought periods between rainfall events), which may have profound effects on terrestrial ecosystems. Plant growth, population and community dynamics in dry environments are likely to be affected by these changes since productivity is already limited by water availability. We tested the effects of reduced precipitation and fewer rain events on three semiarid plant communities dominated by annual species. Location: Three semiarid plant communities from Almería province (SE Spain). Methods: Rain‐out shelters were set up in each community and watering quantity and frequency were manipulated from autumn to early summer. Plant productivity, cover and diversity were measured at the end of the experimental period. Results: We found that a 50% reduction in watering reduced productivity, plant cover and diversity in all three communities. However, neither the 25% reduction in watering nor changes in the frequency of watering events affected these parameters. Conclusions: The lack of response to small reductions in water could be due to the identity and resistance of the plant communities involved, which are adapted to rainfall variability characteristic of arid environments. Therefore, a rainfall reduction of 25% or less may not affect these plant communities in the short term, although higher reductions or long‐term changes in water availability would probably reduce productivity and diversity in these communities.     

Does functional redundancy of communities provide insurance against human disturbances? An analysis using regional-scale stream invertebrate data

Human-induced reductions in species richness might alter the quality of ecosystem services when the remaining species are not able to substitute the functions provided by extirpated species. We examined how human disturbances (nutrient enrichment, land use intensification, instream habitat degradation and the presence of alien species) influence the species richness of stream invertebrates. Stream invertebrates (425 native species) were collected by kick and sweep sampling technique at 274 stream sites covering the entire area of Hungary. We measured the species richness, functional richness (i.e. number of unique functional roles provided by community members) and functional redundancy (i.e. the functional insurance of the community) using information on the feeding habits of each species. To remove the effect of natural variability, we tested the effect of stressors on the residuals of models relating species richness, functional richness and functional redundancy with natural environmental gradients. Our results showed that species richness was negatively influenced by instream habitat degradation and nutrient enrichment. Independent of the way of quantifying functional richness and functional redundancy, we found that functional richness is more sensitive to human impact than functional redundancy of stream invertebrates. The finding that a reduction of species richness is associated with a loss of unique functional roles (functional richness) is important for conservation issues, because the number of unique functional roles is usually regarded as driver of ecosystem functioning.     

Do diet and taxonomy influence insect gut bacterial communities?

Many insects contain diverse gut microbial communities. While several studies have focused on a single or small group of species, comparative studies of phylogenetically diverse hosts can illuminate general patterns of host–microbiota associations. In this study, we tested the hypotheses that (i) host diet and (ii) host taxonomy structure intestinal bacterial community composition among insects. We used published 16S rRNA gene sequence data for 58 insect species in addition to four beetle species sampled from the Sevilleta National Wildlife Refuge to test these hypotheses. Overall, gut bacterial species richness in these insects was low. Decaying wood xylophagous insects harboured the richest bacterial gut flora (102.8 species level operational taxonomic units (OTUs)/sample ± 71.7, 11.8 ± 5.9 phylogenetic diversity (PD)/sample), while bees and wasps harboured the least rich bacterial communities (11.0 species level OTUs/sample ± 5.4, 2.6 ± 0.8 PD/sample). We found evidence to support our hypotheses that host diet and taxonomy structure insect gut bacterial communities (P < 0.001 for both). However, while host taxonomy was important in hymenopteran and termite gut community structure, diet was an important community structuring factor particularly for insect hosts that ingest lignocellulose‐derived substances. Our analysis provides a baseline comparison of insect gut bacterial communities from which to test further hypotheses concerning proximate and ultimate causes of these associations.     

Do hunters target auxiliary markers? An example using black brant

Auxiliary markers play an essential role in understanding migration, movement, demography, and behavior of migratory birds. Use of such markers relies on the assumption that the markers do not affect the traits of interest. Neck collars, among the most conspicuous of markers, substantially affect risk of harvest, and survival even in the absence of harvest. Effects of less-conspicuous markers, such as colored plastic tarsal bands, are not well understood. We used 30 years (1986–2015) of banding, recovery, and recapture data from the Yukon-Kuskokwim Delta in Alaska, USA, to assess differences in direct band recovery rates (DRRs) between black plastic and brightly colored plastic bands applied to black brant (Branta bernicla nigricans). We also assessed the effect of the color of plastic tarsal bands on annual survival, risks of natural mortality harvest, and fidelity to the breeding colony of adult female black brant. When assessing only DRRs we found that brightly colored bands were recovered at higher rates than black plastic bands in the early 2000s, but DRRs for black bands increased more rapidly through time, resulting in similar DRRs for the 2 band colors at the end of the study. Using a Burnham model structure, our results demonstrated that individuals fitted with colored bands had slightly lower hazards of dying from natural causes or hunting than individuals carrying less-conspicuous black tarsal bands. Differences on annual probability scales were small and credible intervals broadly overlapped between band types, indicating minimal differences between individuals with different band types; however, we could not resolve all confounding in our study design and we suggest that specific studies directed at assessing marker effects are warranted. We encourage education of hunters about their roles as citizen scientists and the potentially detrimental effect of targeting birds with auxiliary markers.     

Do bacterial and fungal communities assemble differently during primary succession?

High‐throughput sequencing technologies are now allowing us to study patterns of community assembly for diverse microbial assemblages across environmental gradients and during succession. Here we discuss potential explanations for similarities and differences in bacterial and fungal community assembly patterns along a soil chronosequence in the foreland of a receding glacier. Although the data are not entirely conclusive, they do indicate that successional trajectories for bacteria and fungi may be quite different. Recent empirical and theoretical studies indicate that smaller microbes (like most bacteria) are less likely to be dispersal limited than are larger microbes – which could result in a more deterministic community assembly pattern for bacteria during primary succession. Many bacteria are also better adapted (than are fungi) to life in barren, early‐successional sediments in that some can fix nitrogen and carbon from the atmosphere – traits not possessed by any fungi. Other differences between bacteria and fungi are discussed, but it is apparent from this and other recent studies of microbial succession that we are a long way from understanding the mechanistic underpinnings of microbial community assembly during ecosystem succession. We especially need a better understanding of global and regional patterns of microbial dispersal and what environmental factors control the development of microbial communities in complex natural systems.     

Does phenotypic plasticity confound attempts to identify hominin fossil species? An assessment using extant Old World monkey craniodental data

It has been hypothesised recently that masticatory strain-induced phenotypic plasticity complicates efforts to delineate species in the hominin fossil record. Here, we report a study that evaluated this hypothesis by subjecting craniodental data from 8 Old World monkey species to ANOVA and discriminant analysis. The study does not support the hypothesis. Characters associated with high masticatory strains were found to exhibit significantly higher levels of variability than low-to-moderately strained characters and dental characters, but the three sets of characters did not differ markedly in taxonomic utility. Moreover, the best discrimination was achieved when all variables were employed. These results suggest that phenotypic plasticity likely plays only a minor confounding role in hominin taxonomy, and that, rather than attempting to exclude phenotypically plastic characters, researchers should simply maximise the number of characters examined.     

Climate change and unequal phenological changes across four trophic levels: constraints or adaptations?

1. Climate change has been shown to affect the phenology of many organisms, but interestingly these shifts are often unequal across trophic levels, causing a mismatch between the phenology of organisms and their food. 2. We consider two alternative hypotheses: consumers are constrained to adjust sufficiently to the lower trophic level, or prey species react more strongly than their predators to reduce predation. We discuss both hypotheses with our analyses of changes in phenology across four trophic levels: tree budburst, peak biomass of herbivorous caterpillars, breeding phenology of four insectivorous bird species and an avian predator. 3. In our long-term study, we show that between 1988 and 2005, budburst advanced (not significantly) with 0.17 d yr(-1), while between 1985 and 2005 both caterpillars (0.75 d year(-1)) and the hatching date of the passerine species (range for four species: 0.36-0.50 d year(-1)) have advanced, whereas raptor hatching dates showed no trend. 4. The caterpillar peak date was closely correlated with budburst date, as were the passerine hatching dates with the peak caterpillar biomass date. In all these cases, however, the slopes were significantly less than unity, showing that the response of the consumers is weaker than that of their food. This was also true for the avian predator, for which hatching dates were not correlated with the peak availability of fledgling passerines. As a result, the match between food demand and availability deteriorated over time for both the passerines and the avian predators. 5. These results could equally well be explained by consumers' insufficient responses as a consequence of constraints in adapting to climate change, or by them trying to escape predation from a higher trophic level, or both. Selection on phenology could thus be both from matches of phenology with higher and lower levels, and quantifying these can shed new light on why some organisms do adjust their phenology to climate change, while others do not.     

Do socioeconomic health gradients persist over time and beyond income? A distributional analysis using UK biomarker data

This paper analyses the relationship between health and socioeconomic disadvantage by adopting a dynamic approach accounting for spatial and temporal changes across ten domains including social isolation, environment, financial hardship and security. As a first step we develop a measure of overall multidimensional deprivation and undertake a decomposition analysis to explore the role of breadth and duration of deprivation on shaping the deprivation gradient in health. Subsequently, we employ unconditional quantile regression to conduct a distributional analysis of the gradient to understand how the gradient evolves for people with vulnerability in health. In contrast to the majority of existing studies, we capture health status using a range of nurse measured biomarkers, rather than self reported health measures, taken from the UKHLS and BHPS databases. The first main finding is that the socioeconomic gradient in most of our health measures is not solely attributed to income as it accounts for only 3.8% of total deprivation and thus it is important to account for other domains through a multidimensional deprivation measure in health gradient analysis. Our second finding is the existence of a systematic deprivation gradient for BMI, waist circumference, heart rate, C-reactive protein and HbA1c where evolution over time is an important factor particularly for individuals with greater burden of illness lying at the right tail of the biomarker distribution. Thus cost effective health policy would need to adopt targeted interventions prioritising people experiencing persistent deprivation in dimensions such as housing conditions and social isolation.     

Do nematode and macrofauna assemblages provide similar ecological assessment information?

Do nematode and macrofauna assemblages provide similar ecological assessment information? To answer this question, in the summer of 2006, subtidal soft-bottom assemblages were sampled and environmental parameters were measured at seven stations covering the entire salinity gradient of the Mondego estuary. Principal components analysis (PCA) was performed on the environmental parameters, thus establishing different estuarine stretches. The ecological status of each community was determined by applying the Maturity Index and the Index of Trophic Diversity to the nematode data and the Benthic Assessment Tool to the macrofaunal data. Overall, the results indicated that the answer to the initial question is not straightforward. The fact that nematode and macrofauna have provided different responses regarding environmental status may be partially explained by local differentiation in microhabitat conditions, given by distinct sampling locations within each estuarine stretch and by different response-to-stress times of each benthic community. Therefore, our study suggests that both assemblages should be used in marine pollution monitoring programs.     

The northern Baltic Sea phytoplankton communities in 1903–1911 and 1993–2005: a comparison of historical and modern species data

Despite over 100 years of phytoplankton research in the Baltic Sea, little is known about how the species composition has changed during this period, characterised by severe anthropogenic eutrophication. We investigated the phytoplankton communities in the northern Baltic Sea using data from 1903 to 1911 and 1993 to 2005; to minimise effects of methodological differences we focused on occurrence frequencies. We found that the historical and modern communities differed regarding both species composition and the relative importance of taxonomical groups. The most obvious differences were the increase of dinoflagellates and decrease in the diatom to dinoflagellate ratio in all seasons. Contrary to the widely held view that cyanophytes have gained significance, our results indicate that in terms of occurrence the group has not increased in summer, and has lost ground in both spring and autumn. Several shifts in the occurrence frequency and seasonality of individual taxa transpired. Examining our results in relation to environmental conditions we found that some changes may be symptomatic of climate change related pressures. However, statistical analyses revealed that an undefined ‘period effect’ was the most important factor separating the historical and modern phytoplankton communities. We interpret this ‘period effect’ as evidence for the direct and/or indirect influence of eutrophication.     

Does universal temperature dependence apply to communities? An experimental test using natural marine plankton assemblages

The metabolic theory of ecology (MTE) is an intriguing but controversial theory that tries to explain ecological patterns at all scales on the basis of first principles. Temperature plays a pivotal role in this theory. According to MTE, the Arrhenius relationship that describes the effect of temperature on biochemical reactions extends to a 'universal temperature dependence' that encompasses all kinds of processes and scales up to the cellular, the organismal, and the community level. In this study we test the prediction that community growth rate is temperature dependent in an Arrhenius-like way. First, we performed a literature review of the scanty data on the temperature dependence of the rates of metabolism, photosynthesis and growth of communities. In contrast to the predictions of MTE, the community activation energies did not cluster around 0.32 eV, the activation energy of photosynthesis and primary production or around 0.65 eV, the activation energy of metabolism. However, in none of the published studies the conditions were sufficiently controlled to allow firm conclusions. We therefore also performed replicated and controlled experiments using natural assemblages of marine plankton. As predicted by MTE, the maximal growth rates of community biomass increased linearly in an Arrhenius plot, with a slope close to 0.32 eV. However, a diversity of other models for the temperature dependence of community growth rates fit our data equally well. Hence, our results are at best a weak confirmation of MTE.     

Do metacommunity mass effects predict changes in species incidence and abundance?

Metacommunity matrices contain data on species incidence or abundance across sites, compactly portraying community composition and how it varies over sites. We constructed models based on an initial metacommunity matrix of either species incidence or abundance to test whether such data suffice to predict subsequent changes in incidence or abundance at each site. The models reflect both species and site mass effects in using products of the row and column totals to predict the incidence or abundance of each species expected at each site. We tested these models against empirical data on vascular plant incidence and abundance collected from two sets of forested sites in both the 1950s and 2000s. Predictions from these models parallel observed changes in species incidence and abundance in these distinctly different metacommunities and differ greatly from null model predictions. The abundance model shows greater power than the incidence model reflecting its higher information content. Predictions were more accurate for the more diverse forests of southern Wisconsin that are changing quickly in response to succession and fragmentation. Simulations show that these results are robust but sensitive to sampling intensity. Because these models require no data on site conditions or species’ characteristics, they provide a useful baseline to assess more complex models based on species’ functional traits, local site conditions, or landscape context. They may also prove useful to conservation biologists seeking to predict local population declines and extinction risks.     

Are the Platyhelminthes a monophyletic primitive group? An assessment using 18S rDNA sequences

In most zoological textbooks, Platyhelminthes are depicted as an early- emerging clade forming the likely sister group of all the other Bilateria. Other phylogenetic proposals see them either as the sister group of most of the Protostomia or as a group derived from protostome coelomate ancestors by progenesis. The main difficulty in their correct phylogenetic placing is the lack of convincing synapomorphies for all Platyhelminthes, which may indicate that they are polyphyletic. Moreover, their internal phylogenetic relationships are still uncertain. To test these hypotheses, new complete 18S rDNA sequences from 13 species of "Turbellaria" have been obtained and compared to published sequences of 2 other "Turbellaria," 3 species of parasitic Platyhelminthes, and several diploblastic and deuterostome and protostome triploblastics. Maximum-parsimony, maximum-likelihood, and neighbor-joining methods were used to infer their phylogeny. The results show the order Catenulida to form an independent early- branching clade and emerge as a potential sister group of the rest of the Bilateria, while the rest of Platyhelminthes (Rhabditophora), which includes the parasites, form a clear monophyletic group closely related to the protostomes. The order Acoela, morphologically considered as candidates to be ancestral, are shown to be fast-clock organisms for the 18S rDNA gene. Hence, long-branching of acoels and insufficient sampling of catenulids and acoels leave their position still unresolved and call for further studies. Within the Rhabditophora, our analyses suggest (1) a close relationship between orders Macrostomida and Polycladida, forming a clear sister group to the rest of orders; (2) that parasitic platyhelminthes appeared early in the evolution of the group and form a sister group to a still-unresolved clade made by Nemertodermatida, Lecithoepitheliata, Prolecithophora, Proseriata, Tricladida, and Rhabdocoela; and (3) that Seriata is paraphyletic.      

Do cladistic and morphometric data capture common patterns of morphological disparity?

The distinctly non‐random diversity of organismal form manifests itself in discrete clusters of taxa that share a common body plan. As a result, analyses of disparity require a scalable comparative framework. The difficulties of applying geometric morphometrics to disparity analyses of groups with vastly divergent body plans are overcome partly by the use of cladistic characters. Character‐based disparity analyses have become increasingly popular, but it is not clear how they are affected by character coding strategies or revisions of primary homology statements. Indeed, whether cladistic and morphometric data capture similar patterns of morphological variation remains a moot point. To address this issue, we employ both cladistic and geometric morphometric data in an exploratory study of disparity focussing on caecilian amphibians. Our results show no impact on relative intertaxon distances when different coding strategies for cladistic characters were used or when revised concepts of homology were considered. In all instances, we found no statistically significant difference between pairwise Euclidean and Procrustes distances, although the strength of the correlation among distance matrices varied. This suggests that cladistic and geometric morphometric data appear to summarize morphological variation in comparable ways. Our results support the use of cladistic data for characterizing organismal disparity.