Toucans (Ramphastos ambiguus) facilitate resilience against seed dispersal limitation to a large‐seeded tree (Virola surinamensis) in a human‐modified landscape

Large‐seeded plants may suffer seed dispersal limitation in human‐modified landscapes if seed dispersers are absent or unable to disperse their seeds. We investigated dispersal limitation for the large‐seeded tree Virola surinamensis in a human‐modified landscape in southern Costa Rica. During two fruiting seasons, we monitored crop size, seed removal rates, the number of fruiting conspecifics within 100 m, and feeding visitation rates by frugivores at trees located in high and low forest disturbance conditions. Seed removal rates and the total number of seeds removed were high regardless of the disturbance level, but these parameters increased with tree crop size and decreased with the number of fruiting V. surinamensis trees within a 100 m radius. Trees at low disturbance levels were more likely to be visited by seed dispersers. Black mandibled toucans (Ramphastos ambiguus) and spider monkeys (Ateles geoffroyi) were the most important seed dispersers, based on visitation patterns and seed removal rates. Spider monkey feeding visits were more frequent at high disturbance levels, but the monkeys preferentially visited isolated trees with large yields and surrounded by a low number of fruiting Virola trees within 100 m. Toucan visitation patterns were not constrained by any of the predictors and they visited trees equally across the landscape. We suggest that isolated and highly fecund Virola trees are an important food resource for spider monkeys in human‐modified landscapes and that toucans can provide resilience against seed dispersal limitations for large‐seeded plants in human‐modified landscapes in the absence of hunting.     

Evolution of sociality in spiders leads to depleted genomic diversity at both population and species levels

Across several animal taxa, the evolution of sociality involves a suite of characteristics, a “social syndrome,” that includes cooperative breeding, reproductive skew, primary female‐biased sex ratio, and the transition from outcrossing to inbreeding mating system, factors that are expected to reduce effective population size (Ne). This social syndrome may be favoured by short‐term benefits but come with long‐term costs, because the reduction in Ne amplifies loss of genetic diversity by genetic drift, ultimately restricting the potential of populations to respond to environmental change. To investigate the consequences of this social life form on genetic diversity, we used a comparative RAD‐sequencing approach to estimate genomewide diversity in spider species that differ in level of sociality, reproductive skew and mating system. We analysed multiple populations of three independent sister‐species pairs of social inbreeding and subsocial outcrossing Stegodyphus spiders, and a subsocial outgroup. Heterozygosity and within‐population diversity were sixfold to 10‐fold lower in social compared to subsocial species, and demographic modelling revealed a tenfold reduction in Ne of social populations. Species‐wide genetic diversity depends on population divergence and the viability of genetic lineages. Population genomic patterns were consistent with high lineage turnover, which homogenizes the genetic structure that builds up between inbreeding populations, ultimately depleting genetic diversity at the species level. Indeed, species‐wide genetic diversity of social species was 5–8 times lower than that of subsocial species. The repeated evolution of species with this social syndrome is associated with severe loss of genomewide diversity, likely to limit their evolutionary potential.     

Male and female range use in a group of white‐bellied spider monkeys (Ateles belzebuth) in Yasuní National Park,Ecuador

Spider monkeys (Ateles sp.) live in a flexible fission–fusion social system in which members of a social group are not in constant association, but instead form smaller subgroups of varying size and composition. Patterns of range use in spider monkeys have been described as sex‐segregated, with males and females often ranging separately, females utilizing core areas that encompass only a fraction of the entire community range, and males using much larger portions of the community range that overlap considerably with the core areas of females and other males. Males are also reported to use the boundary areas of community home ranges more often than females. Spider monkeys thus seem to parallel the “male‐bonded” patterns of ranging and association found among some groups of chimpanzees. Over several years of research on one group of spider monkeys (Ateles belzebuth) in Yasuní National Park, Ecuador, we characterized the ranging patterns of adult males and females and evaluated the extent to which they conform to previously reported patterns. In contrast to ranging patterns seen at several other spider monkey sites, the ranges of our study females overlapped considerably, with little evidence of exclusive use of particular areas by individual monkeys. Average male and female home range size was comparable, and males and females were similar in their use of boundary areas. These ranging patterns are similar to those of “bisexually bonded” groups of chimpanzees in West Africa. We suggest that the less sex‐segregated ranging patterns seen in this particular group of spider monkeys may be owing to a history of human disturbance in the area and to lower genetic relatedness between males, highlighting the potential for flexibility some aspects of the spider monkeys' fission–fusion social system. Am. J. Primatol. 72:129–141, 2010. © 2009 Wiley‐Liss, Inc.     

Dispersión Primaria de Semillas por Primates y Dispersión Secundaria por Escarabajos Coprófagos en Tikal,Guatemala1

We linked primary dispersal by spider monkeys (Ateles geoffroyi) and howler monkeys (Alouatta pigra) to post‐dispersal seed fate by studying the effects of dung type and defecation pattern on secondary seed dispersal by dung beetles. First, we described the defecation patterns for both primate species. Howler monkeys generally defecated in groups (88% of observed defecations), with each individual producing on average 31 g of dung, resulting in a large area of the forest floor (31 m²) covered by large amounts of dung (clumped spatial pattern). Spider monkeys generally (96% of observed defecations) defecated individually, each individual producing an average of 11 g of dung, resulting in a small area of the forest floor (2 m²) covered by small amounts of dung (scattered spatial pattern). Secondly, we captured dung beetles using as bait the dung of both primate species, to detect differences in the assemblages of these secondary seed dispersers attracted to the dung of both primates. More individual dung beetles, but not more species, were attracted to howler monkey dung than to spider monkey dung. Finally, we assessed experimentally (using plastic beads as seed mimics) how dung type (Ateles vs. Alouatta) and defecation pattern (scattered vs. clumped) affect secondary seed dispersal by dung beetles. We found that post‐dispersal seed fate was affected by dung type, with more seeds being buried when present in howler monkey dung, than in spider monkey dung, but was not affected by defecation pattern. It is important to consider post‐dispersal processes, such as secondary seed dispersal by dung beetles, when comparing species of primary dispersers.     

Group size and stability: Why do gibbons and spider monkeys differ?

Gibbons and spider monkeys have similar diets, body size, and locomotor patterns. They are therefore expected to be subject to similar socioecological rules. However their grouping patterns differ. Gibbons live in small stable groups, whereas spider monkey form unstable sub-groups that vary from small to large during different seasons. If similar principles apply to the two species, food abundance should vary more for spider monkeys than for gibbons; food density should be similar for the two species when spider monkey sub-groups are the same size as gibbon groups; and the highest level of food abundance should be higher for spider monkeys than for gibbons. These predictions are upheld for a comparison of particular populations ofHylobates muelleri andAteles geoffroyi.     

Cover Caption

Spider mites are notorious agricultural pests worldwide. A male adult of Tetranychus truncatus is waiting for mating with a female. Spider mites harbor diverse bacterial communities, whose structure could be affected by many factors. We found that host species is the primary determinant of the microbiome composition of spider mites. Also, the microbiome of spider mite feces potentially reflects the gut bacterial community in spider mites (see pages 859‐868). Photo provided by Xiao‐Yue Hong of Nanjing Agricultural University, China.     

Foraging,Food Choice,and Food Processing by Sympatric Ripe-Fruit Specialists: <Emphasis Type="Italic">Lagothrix lagotricha poeppigii</Emphasis> and <Emphasis Type="Italic">Ateles belzebuth belzebuth</Emphasis>

Studies of interspecific competition and niche separation have formed some of the seminal works of ecology. I conducted an 18-mo study comparing the feeding ecologies of 2 sympatric, closely-related ripe-fruit specialists, Humboldt's woolly monkeys (Lagothrix lagotricha poeppigii), and the white-bellied spider monkeys (Ateles belzebuth belzebuth) in Amazonian Ecuador. Woolly monkeys in the terra firme forest live at roughly triple the density of spider monkeys (31 versus 11.5 animals/km²). Woolly monkeys spend 17% of their time foraging, while spider monkeys spend only 1% of their time foraging. Spider monkeys alone fed on soil and termitaria, which are rich in phosphorus. Woolly monkeys are not hard-fruit specialists. Their fruit diet is significantly more diverse than that of spider monkeys. Dietary overlap between the 2 species is high, yet each specializes to some degree on a different set of fruit resources. Woolly monkeys visit more food sources per unit of time, feed lower in the canopy, visit more small food patches, and prey on more seeds. Spider monkeys feed on fewer, richer food sources and are more than twice as likely to return to a particular fruit source than woolly monkeys are. Spider monkeys maximize fruit pulp intake, carrying more intact seeds in their guts, while woolly monkeys minimize seed bulk swallowed through more careful food processing. Surprisingly, several preferred spider monkey foods with high fat content and large seeds are avoided by woolly monkeys. I outline the different ecological dimensions involved in niche separation between the 2 species and discuss the possible impetus for their evolutionary divergence.     

Recent colonization by a coastal plant of inland habitats at an ancient freshwater lake,Lake Biwa: multilocus sequencing and a demographic history of Lathyrus japonicus (Fabaceae)

Ancient lakes have been recognized as “long‐term isolated islands” in terrestrial ecosystems. Lake Biwa, one of the few ancient lakes that formed around 4 million years ago, harbors many coastal species that commonly inhabit seashores. The beach pea, Lathyrus japonicus, is a typical coastal species of this freshwater lake, where morphological, physiological, and genetic differentiations have been reported between Biwa and coastal populations. Whether Biwa populations were isolated for long periods throughout Pleistocene climatic oscillations and subsequent range shifts is unclear. We assessed population genetic structure and demography of beach pea in this ancient freshwater lake using the sequences of eight nuclear loci. The results of STRUCTURE analyses showed evidence of admixture between Biwa and coastal populations, reflecting recent gene flow. The estimated demographic parameters implemented by the isolation with migration model (IM model) revealed a recent divergence (postglacial period) of Biwa populations, with some gene flow from Biwa to coastal populations. In addition, Biwa populations were significantly smaller in size than the ancestral or coastal populations. Our study suggests that a Holocene thermal maximum, when transgression could allow seeds from coastal plants to access Lake Biwa, was involved in the origin of the Biwa populations and their genetic divergence. Thus, coastal populations might have migrated to Lake Biwa relatively recently. Our study concluded that ancestral migrants in Lake Biwa were derived from small founding populations and accelerated genetic isolation of Biwa populations during short‐term isolation.     

Consequences of multiple mating‐system shifts for population and range‐wide genetic structure in a coastal dune plant

Evolutionary transitions from outcrossing to selfing can strongly affect the genetic diversity and structure of species at multiple spatial scales. We investigated the genetic consequences of mating‐system shifts in the North American, Pacific coast dune endemic plant Camissoniopsis cheiranthifolia (Onagraceae) by assaying variation at 13 nuclear (n) and six chloroplast (cp) microsatellite (SSR) loci for 38 populations across the species range. As predicted from the expected reduction in effective population size (N_e) caused by selfing, small‐flowered, predominantly selfing (SF) populations had much lower nSSR diversity (but not cpSSR) than large‐flowered, predominantly outcrossing (LF) populations. The reduction in nSSR diversity was greater than expected from the effects of selfing on N_e alone, but could not be accounted for by indirect effects of selfing on population density. Although selfing should reduce gene flow, SF populations were not more genetically differentiated than LF populations. We detected five clusters of nSSR genotypes and three groups of cpSSR haplotypes across the species range consisting of parapatric groups of populations that usually (but not always) differed in mating system, suggesting that selfing may often initiate ecogeographic isolation. However, lineage‐wide genetic variation was not lower for selfing clusters, failing to support the hypothesis that selection for reproductive assurance spurred the evolution of selfing in this species. Within three populations where LF and SF plants coexist, we detected genetic differentiation among diverged floral phenotypes suggesting that reproductive isolation (probably postzygotic) may help maintain the striking mating‐system differentiation observed across the range of this species.     

Unusually limited pollen dispersal and connectivity of Pedunculate oak (Quercus robur) refugial populations at the species' southern range margin

Low‐latitudinal range margins of temperate and boreal plant species typically consist of scattered populations that persist locally in microrefugia. It remains poorly understood how their refugial habitats affect patterns of gene flow and connectivity, key components for their long‐term viability and evolution. We examine landscape‐scale patterns of historical and contemporary gene flow in refugial populations of the widespread European forest tree Pedunculate oak (Quercus robur) at the species' southwestern range margin. We sampled all adult trees (n = 135) growing in a 20 km long valley and genotyped 724 acorns from 72 mother trees at 17 microsatellite loci. The ten oak stands that we identified were highly differentiated and formed four distinct genetic clusters, despite sporadic historical dispersal being detectable. By far most contemporary pollination occurred within stands, either between local mates (85.6%) or through selfing (6.8%). Pollen exchange between stands (2.6%) was remarkably rare given their relative proximity and was complemented by long‐distance pollen immigration (4.4%) and hybridization with the locally abundant Quercus pyrenaica (0.6%). The frequency of between‐stand mating events decreased with increasing size and spatial isolation of stands. Overall, our results reveal outstandingly little long‐distance gene flow for a wind‐pollinated tree species. We argue that the distinct landscape characteristics of oaks' refugial habitats, with a combination of a rugged topography, dense vegetation and humid microclimate, are likely to increase plant survival but to hamper effective long‐distance pollen dispersal. Moreover, local mating might be favoured by high tree compatibility resulting from genetic purging in these long‐term relict populations.     

The Influence of Translocation Strategy and Management Practices on the Genetic Variability of a Reestablished Elk (Cervus elaphus) Population

Reintroduction of terrestrial vertebrates with the goal of ecosystem restoration typically establishes small and isolated populations that may experience reduced genetic variability due to founder effects and genetic drift. Understanding the genetic structure of these populations and maintaining adequate genetic diversity is important for long‐term restoration success. We quantified genetic variability at six microsatellite loci for a reintroduced population of Cervus elaphus (elk) restored to the tallgrass prairie ecosystem of northeastern Kansas. Allelic richness, observed and expected heterozygosity were intermediate to levels reported in other North American elk populations. Current levels of genetic variability in restored North American elk populations were not well explained by founding population size, number of founding populations, or number of years since the last translocation. Simulation results suggest that the retention of genetic variability in isolated populations is strongly influenced by mating system while also being impacted by temporal variability in population size and population growth rate. Our results have implications for understanding how translocation strategies and post‐reintroduction management may influence genetic variability in restored populations.     

Differences in Diet Between Spider Monkey Groups Living in Forest Fragments and Continuous Forest in Mexico

Forest fragmentation can lead to reductions in food availability, especially for some large‐bodied tropical mammals such as spider monkeys. During a 15\xE2\x80\x90mo period, we assessed the diet of Geoffroyi's spider monkey (Ateles geoffroyi) in continuous forest and fragments in the Lacandona region, southern Mexico, and related differences in diet to differences in vegetation structure and composition. We found that both forest types presented top food species for monkeys (e.g., Spondias spp., Brosimum alicastrum), but the sum of the importance value index of these species and the density of large trees were lower in fragments than in continuous forest. We also found that, compared with continuous forest, monkeys in fragments diversified their overall diet, increased consumption of leaves, and reduced the time they spent feeding on trees in favor of more time feeding on hemiepiphytes (particularly Ficus spp.) and palms, both of which were common in fragments. We attribute these changes to the relative food scarcity of the most favored feeding plants in forest fragments. Overall, our findings suggest that monkeys are able to adjust their diet to food availability in fragments, and thus persist in small‐ and medium‐sized fragments. Although it is unlikely that the small size of two of the three study fragments (14 and 31 ha) can maintain viable populations of monkeys in the long term, they may function as stepping stones, facilitating inter‐fragment movements and ultimately enhancing seed dispersal in fragmented landscapes.     

Comparative multilocus phylogeography of two Palaearctic spruce bark beetles: influence of contrasting ecological strategies on genetic variation

While phylogeographic patterns of organisms are often interpreted through past environmental disturbances, mediated by climate changes, and geographic barriers, they may also be strongly influenced by species‐specific traits. To investigate the impact of such traits, we focused on two Eurasian spruce bark beetles that share a similar geographic distribution, but differ in their ecology and reproduction. Ips typographus is an aggressive tree‐killing species characterized by strong dispersal, whereas Dendroctonus micans is a discrete inbreeding species (sib mating is the rule), parasite of living trees and a poor disperser. We compared genetic variation between the two species over both beetles’ entire range in Eurasia with five independent gene fragments, to evaluate whether their intrinsic differences could have an influence over their phylogeographic patterns. We highlighted widely divergent patterns of genetic variation for the two species and argue that the difference is indeed largely compatible with their contrasting dispersal strategies and modes of reproduction. In addition, genetic structure in I. typographus divides European populations in a northern and a southern group, as was previously observed for its host plant, and suggests past allopatric divergence. A long divergence time was estimated between East Asian and other populations of both species, indicating their long‐standing presence in Eurasia, prior to the last glacial maximum. Finally, the strong population structure observed in D. micans for the mitochondrial locus provides insights into the recent colonization history of this species, from its native European range to regions where it was recently introduced.     

Glacial refugia and postglacial expansion of the alpine–prealpine plant species Polygala chamaebuxus

The shrubby milkwort (Polygala chamaebuxus L.) is widely distributed in the Alps, but occurs also in the lower mountain ranges of Central Europe such as the Franconian Jura or the Bohemian uplands. Populations in these regions may either originate from glacial survival or from postglacial recolonization. In this study, we analyzed 30 populations of P. chamaebuxus from the whole distribution range using AFLP (Amplified Fragment Length Polymorphism) analysis to identify glacial refugia and to illuminate the origin of P. chamaebuxus in the lower mountain ranges of Central Europe. Genetic variation and the number of rare fragments within populations were highest in populations from the central part of the distribution range, especially in the Southern Alps (from the Tessin Alps and the Prealps of Lugano to the Triglav Massiv) and in the middle part of the northern Alps. These regions may have served, in accordance with previous studies, as long‐term refugia for the glacial survival of the species. The geographic pattern of genetic variation, as revealed by analysis of molecular variance, Bayesian cluster analysis and a PopGraph genetic network was, however, only weak. Instead of postglacial recolonization from only few long‐term refugia, which would have resulted in deeper genetic splits within the data set, broad waves of postglacial expansion from several short‐term isolated populations in the center to the actual periphery of the distribution range seem to be the scenario explaining the observed pattern of genetic variation most likely. The populations from the lower mountain ranges in Central Europe were more closely related to the populations from the southwestern and northern than from the nearby eastern Alps. Although glacial survival in the Bohemian uplands cannot fully be excluded, P. chamaebuxus seems to have immigrated postglacially from the southwestern or central‐northern parts of the Alps into these regions during the expansion of the pine forests in the early Holocene.     

Reproductive biology of captive and free-ranging spider monkeys

Records from 42 zoos and from long-term studies of wild populations were analysed to describe the reproductive biology of spider monkeys (Ateles spp.). Both data sets suggested that spider monkey females typically have their first infant between 7 and 8 years of age with an interbirth interval of approximately 32–36 months. Infant sex ratio for zoo populations was approximately 1 male to 1 female; infant sex ratios from wild populations were variable. Zoo records provided adequate sample size to suggest that interbirth interval was not influenced by the sex of the infant produced, and that the sex ratio and the probability of infant survival did not change with the number of infants the mother had produced. The findings of this study have implications with respect to the conservation of New World primate species. Since spider monkeys take a long time to reach sexual maturity and their interbirth interval is longer than that expected based on their body size, their populations may be slow to recover following disturbances. Thus, particular care should be taken for the protection of these species.     

Survey of black howler (<Emphasis Type="Italic">Alouatta pigra</Emphasis>) and spider (<Emphasis Type="Italic">Ateles geoffroyi</Emphasis>) monkeys in the Mayan sites of Calakmul and Yaxchilán,Mexico and Tikal,Guatemala

Surveys of populations of spider and howler monkeys were conducted at the Mayan sites of Calakmul and Yaxchilán, Mexico and Tikal, Guatemala. The forests in which these sites are found are part of the largest landmass of tropical rain forests present in Mesoamerica, encompassing about 4 million ha. Triangulation of monkey vocalization combined with ground surveys was used to determine the presence of howler and spider monkey groups. Howler monkey mean troop size at these sites varied from 6.6±2.1 individuals in Yaxchilán to 7.5±1.9 in Calakmul to 8.7±2.2 in Tikal. Density estimates varied from 12.8 individuals/km² in Yaxchilán to 15.2 individuals/km² in Calakmul to 17.8 individuals/km² in Tikal. Mean spider monkey subgroup size varied from 4.7±2.6 individuals in Tikal to 5.6±3.0 individuals in Yaxchilán to 7.7±3.8 individuals in Calakmul. Spider monkey density varied from 17.0 individuals/km² in Yaxchilán to 17.2 individuals/km² in Calakmul to 56.4 individuals/km² in Tikal. All sightings of both howler and spider monkeys at the three sites were in undisturbed rain forest vegetation and spider monkeys in general were more frequently sighted at higher tree heights than howlers. We discuss the value of further acquiring data on howler and spider monkey populations existing in extensive forest tracts and on the conservation value for both primate species of the forests surrounding the Mayan ruins found in this area of Mesoamerica.     

No evidence for MHC‐based mate choice in wild giant pandas

Major histocompatibility complex genes (MHC), a gene cluster that controls the immune response to parasites, are regarded as an important determinant of mate choice. However, MHC‐based mate choice studies are especially rare for endangered animals. The giant panda (Ailuropoda melanoleuca), a flagship species, has suffered habitat loss and fragmentation. We investigated the genetic variation of three MHC class II loci, including DRB1, DQA1, and DQA2, for 19 mating‐pairs and 11 parent‐pairs of wild giant pandas based on long‐term field behavior observations and genetic samples. We tested four hypotheses of mate choice based on this MHC variation. We found no supporting evidence for the MHC‐based heterosis, genetic diversity, genetic compatibility and “good gene” hypotheses. These results suggest that giant pandas may not use MHC‐based signals to select mating partners, probably because limited mating opportunities or female‐biased natal dispersal restricts selection for MHC‐based mate choice, acknowledging the caveat of the small sample size often encountered in endangered animal studies. Our study provides insight into the mate choice mechanisms of wild giant pandas and highlights the need to increase the connectivity and facilitate dispersal among fragmented populations and habitats.     

Stochastic modelling of shifts in allele frequencies reveals a strongly polygynous mating system in the re‐introduced Asiatic wild ass

Small populations are prone to loss of genetic variation and hence to a reduction in their evolutionary potential. Therefore, studying the mating system of small populations and its potential effects on genetic drift and genetic diversity is of high importance for their viability assessments. The traditional method for studying genetic mating systems is paternity analysis. Yet, as small populations are often rare and elusive, the genetic data required for paternity analysis are frequently unavailable. The endangered Asiatic wild ass (Equus hemionus), like all equids, displays a behaviourally polygynous mating system; however, the level of polygyny has never been measured genetically in wild equids. Combining noninvasive genetic data with stochastic modelling of shifts in allele frequencies, we developed an alternative approach to paternity analysis for studying the genetic mating system of the re‐introduced Asiatic wild ass in the Negev Desert, Israel. We compared the shifts in allele frequencies (as a measure of genetic drift) that have occurred in the wild ass population since re‐introduction onset to simulated scenarios under different proportions of mating males. We revealed a strongly polygynous mating system in which less than 25% of all males participate in the mating process each generation. This strongly polygynous mating system and its potential effect on the re‐introduced population's genetic diversity could have significant consequences for the long‐term persistence of the population in the Negev. The stochastic modelling approach and the use of allele‐frequency shifts can be further applied to systems that are affected by genetic drift and for which genetic data are limited.     

Successional loss of two key food tree species best explains decline in group size of Panamanian howler monkeys (Alouatta palliata)

Negative impacts of discrete, short‐term disturbances to wildlife populations are well‐documented. The consequences of more gradual environmental change are less apparent and harder to study because they play out over longer periods and are often indirect in their action. Yet, they can drive the decline of wildlife populations even in seemingly pristine and currently well‐protected habitats. One such environmental change is a successional shift in a community's species composition as it regenerates from disturbance caused by past human land use. Early and middle successional tree species often provide key foods to folivores and frugivores, but the abundance of these resources drops as the forest matures, with adverse repercussions for these consumers. Our 44‐year record (1974–2018) of howler monkey (Alouatta palliata) group sizes and demographic composition from Barro Colorado Island, Panama, a protected reserve, documents an example of this phenomenon. After 70 years of relative stability, the mean size of howler monkey groups exhibited a marked decline, beginning in 2003. This downward trajectory in group size has continued through the most recent census in 2018. The composition of howler groups also changed significantly during the study period, with the patterns of decline differing among age/sex classes. There is no evidence that these changes were caused by increased rates of emigration, group fission, predation, parasitism, or disease. Rather, they are best explained by an island‐wide, succession‐driven decline in the densities of two species of free‐standing fig trees, Ficus yoponensis and F. insipida, which together were providing ~36% of BCI howlers’ annual diet. Abstract in Spanish is available with online material.     

Low genetic variability and strong differentiation among isolated populations of the rare steppe grass Stipa capillata L. in Central Europe

Stipa capillata L. (Poaceae) is a rare grassland species in Central Europe that is thought to have once been widespread in post‐glacial times. Such relict species are expected to show low genetic diversity within populations and high genetic differentiation between populations due to bottlenecks, long‐term isolation and ongoing habitat fragmentation. These patterns should be particularly pronounced in selfing species. We analysed patterns of random amplified polymorphic DNA (RAPD) variation in the facultatively cleistogamous S. capillata to examine whether genetic diversity is associated with population size, and to draw initial conclusions on the migration history of this species in Central Europe. We analysed 31 S. capillata populations distributed in northeastern, central and western Germany, Switzerland and Slovakia. Estimates of genetic diversity at the population level were low and not related to population size. Among all populations, extraordinarily high levels of genetic differentiation (amova : φ_ST = 0.86; Bayesian analysis: θ^B = 0.758) and isolation‐by‐distance were detected. Hierarchical amova indicated that most of the variability was partitioned among geographic regions (59%), or among populations between regions when the genetically distinct Slovakian populations were excluded. These findings are supported by results of a multivariate ordination analysis. We also found two different groups in an UPGMA cluster analysis: one that contained the populations from Slovakia, and the other that combined the populations from Germany and Switzerland. Our findings imply that S. capillata is indeed a relict species that experienced strong bottlenecks in Central Europe, enhanced by isolation and selfing. Most likely, populations in Slovakia were not the main genetic source for the post‐glacial colonization of Central Europe.