Habitat requirements of Eurasian pine marten <Emphasis Type="Italic">Martes martes</Emphasis> in a Mediterranean environment

Evaluating presence and habitat requirements of small carnivores is essential for their conservation. The Eurasian pine marten Martes martes, often described as a habitat specialist associated primarily with forest habitats, has been recently found to live even in patchily wooded country and in shrublands. We evaluated the environmental factors that determine the distribution of the pine marten in a Mediterranean landscape on the island of Sardinia (central Italy). Camera trapping sessions and scat surveys were carried out to assess the presence of the species, then a potential distribution model was developed using ecological niche factor analysis (ENFA), which requires only presence data. The pine marten selected highest altitudes, shrublands, rocky areas, and woodlands, and avoided urban areas and arable lands. Our results indicate that pine marten distribution in our study area is constrained by these variables. The ENFA analysis provided important clues about the distribution range of M. martes and its preferential environmental conditions, updating knowledge of its ecological requirements in Italy.     

Anthropogenic and Climatic Effects on the Distribution of <Emphasis Type="Italic">Eulemur</Emphasis> Species: An Ecological Niche Modeling Approach

Several factors can influence primate distributions, including evolutionary history, interspecific competition, climate, and anthropogenic impacts. In Madagascar, several small spatial scale studies have shown that anthropogenic habitat modification affects the density and distribution of many lemur species. Ecological niche models can be used to examine broad-scale influences of anthropogenic impacts on primate distributions. In this study, we examine how climate and anthropogenic factors influence the distribution of 11 Eulemur species using ecological niche models. Specifically, we created one set of models only using rainfall and temperature variables. We then created a second set of models that combined these climate variables with three anthropogenic factors: distance to dense settlements, villages, and croplands. We used MaxEnt to generate all the models. We found that the addition of anthropogenic variables improved the climate models. Also, most Eulemur species exhibited reduced predicted geographic distributions once anthropogenic factors were added to the model. Distance to dense settlements was the most important anthropogenic factor in most cases. We suggest that including anthropogenic variables in ecological niche models is important for understanding primate distributions, especially in regions with significant human impacts. In addition, we identify several Eulemur species that were most affected by anthropogenic factors and should be the focus of increased conservation efforts.     

Nuclear genetic variation of <Emphasis Type="Italic">Rosa odorata</Emphasis> var. <Emphasis Type="Italic">gigantea</Emphasis> (Rosaceae): population structure and conservation implications

Rosa odorata var. gigantea is one of the most important ancestors of modern roses, which owns many merit traits including large flower, early flowering, and tea scent. Due to habitat loss and fragmentation, it has been listed as a rare and endangered species in China. In this study, a total of 424 accessions from 27 locations across its major distribution range were sampled. Its genetic diversity and population structure were assessed using a combination of seven nuclear microsatellite markers and one single-copy nuclear gene. Moderate to high within-population genetic diversity and moderate differentiation among populations were revealed despite its narrow distribution. The sampled 27 populations were resolved into two genetic clusters with limited contemporary and historical gene flows. The Red River Fault Zone was inferred to be a physical or geographical barrier to gene flow between these two genetic clusters. Genetic distances were significantly associated with geographic distances, indicating the isolation-by-distance model. Our ecological niche modeling indicated that R. odorata var. gigantea had high current potential areas in the central Yunnan province and substantial losses of high potential distribution areas in the western Yunnan in the future. Two detected clusters showed significant genetic differentiation and represented two separate evolutionary lineages, which should be recognized as two evolutionary significant units (ESUs) for conservation concerns. These results could be applied for the decision-making and conservation planning for this important species.     

Climatic Similarity of Extant and Extinct <Emphasis Type="Italic">Dasypus</Emphasis> Armadillos

The similar geographic distributions of an extinct (Dasypus bellus) and an extant (D. novemcinctus) armadillo species have long been of interest to scholars because of the unresolved phylogeny. The relationship between the two species has been investigated through morphological and phylogenetic studies, whereas the ecological perspective has been overlooked, the importance of which is more and more acknowledged in speciation events. Here, we used ecological niche models to study the climatic niche similarity of three species of Dasypus (D. bellus, D. novemcinctus, and D. kappleri) and provide new insights on the relationship among them. The climatic niche similarity was compared in two ways: hindcast of ecological niche models based on occurrences and climatic layers, and direct niche boundary comparison along bioclimatic axes. The fossil records of D. bellus were not predicted suitable by the ecological niche models of the two extant armadillos. The direct comparison of niche boundary showed that D. bellus lived in colder and relative dryer climates, with high temperature variation and low precipitation variation. Our results did not support the previously assumed ecological similarity of D. bellus and D. novemcinctus based on their geographic distributions and emphasized the possibility of a cold adapted characteristic of the life history of D. bellus.     

Ecological and Anthropogenic Correlates of Activity Patterns in <Emphasis Type="Italic">Eulemur</Emphasis>

The ultimate determinants of cathemerality, i.e., activity spread over the 24-h cycle, in primates have been linked to various ecological factors. Owing to the fast rate of habitat modification, it is imperative to know whether and how this behavioral flexibility responds to anthropogenic disturbance. The true lemurs (Eulemur clade) constitute a valuable case to study these potential effects, as all species studied so far exhibit cathemerality. Here we explored the effects of anthropogenic disturbance on activity patterns of Eulemur while controlling for ecological factors proposed as determinants of activity shifts. We first performed a meta-analysis using 13 long-term studies conducted over the last three decades on various populations of Eulemur. We fitted a beta regression using the proportion of diurnality (the activity taking place between sunrise and sunset) as the response variable and seven climatic, ecological, and anthropogenic disturbance variables at each site as predictors. We also present a validation with original data using year-round, 24-h activity of collared brown lemurs (Eulemur collaris) in forest fragments with different levels of disturbance in southeastern Madagascar. Diurnality was prevalent at most sites. Seasonality, proportions of leaves in the diet, and group size were all found to be significant predictors of the proportion of diurnal activity. After controlling for socioecological factors in the model, overall anthropogenic disturbance emerged as a negative predictor of diurnality. Our validation suggests that the lemurs in the more disturbed area exhibited more nocturnal activity than those in the less disturbed area. It is unclear whether the plasticity observed might allow populations of Eulemur to persist in disturbed areas longer than lemurs with less flexible activity patterns.     

Combined effects of climate,habitat, and disturbance on seedling establishment of <Emphasis Type="Italic">Pinus pinaster</Emphasis> and <Emphasis Type="Italic">Eucalyptus globulus</Emphasis>

The natural expansion of forestry trees into habitats outside plantations is a concern for managers and conservationists. We studied seedling emergence and survival of the two main forestry species in Portugal: Eucalyptus globulus (exotic) and Pinus pinaster (native); using a seed addition experiment. Our main objective was to evaluate the combined effects of climate (mild-summer and warm-summer climate), habitat (oak forest and shrubland), and disturbance (vegetation removal and non-disturbance) on the seedling establishment of species in semi- and natural habitats. Furthermore, we tested the effect of the “sowing season” (autumn and spring) on seedling emergence and survival. Overall, seedling establishment of both species was enhanced by light and water. However, we found important interactions among climate, habitat, and disturbance on both species’ emergence and survival. The differences between habitats were more evident in the mild-summer climate than in the warm-summer climate. Our results also suggested that seedling survival may be enhanced by shrub cover in drier conditions (warm-summer climate). Eucalyptus globulus appears more sensitive to drought and disturbance changes than P. pinaster. In shrublands and mild-summer climate conditions, disturbance especially promoted E. globulus seedling establishment, while the forest canopy and the shade appeared to control it in both climatic conditions. After the first summer life, very low seedling survival was observed in both species, although the colonization of new areas appeared to be more limited for E. globulus. Our study suggests that climate conditions influence the effect (direction and intensity) of habitat and disturbance (plant–plant interactions) on seedling survival. Thus, the effect of light availability (forest canopy) and disturbance (vegetation removal) on these species establishment is climate context-dependent. This study presents very useful information to understand future shifts in these species distribution and has direct applications for the management of natural establishment outside the planted areas, and the management of the understorey to favor forest regeneration or limit forest colonization.     

Vegetation Thresholds for the Occurrence and Dispersal of <Emphasis Type="Italic">Microcebus griseorufus</Emphasis> in Southwestern Madagascar

Primate populations are declining the world over due to anthropogenic threats, including habitat loss and degradation. This raises the important question of how much habitat degradation a species can cope with. Habitat degradation is pronounced in Madagascar, where most of the human population depends on the direct exploitation of natural resources. We aimed to identify the response of Microcebus griseorufus (the gray-brown mouse lemur) to forest degradation and to define the structural traits of the vegetation that might be crucial for the species’ occurrence in anthropogenic landscapes. We documented the occurrence of Microcebus griseorufus in relation to vegetation structures along a gradient of forest degradation, at the edge of and west of Tsimanampetsotsa National Park in April and May 2007 and from October to December 2015. We confirmed the occurrence of Microcebus griseorufus using trapping and visual surveys, and measured vegetation structure. Logistic regression models showed that Microcebus griseorufus has a threshold response to tree density and the diameter of thick trees. The thresholds of occurrence were at 10–15% of the tree density recorded in intact forest and a mean diameter of trees with a diameter at breast height of >10 cm of 14.3 cm. The definition of such thresholds might help to maintain suitable habitat for this species and other primates living in anthropogenic landscapes, providing connectivity between isolated protected areas and allowing dispersal between populations.     

Predicted and verified distributions of <Emphasis Type="Italic">Ateles geoffroyi</Emphasis> and <Emphasis Type="Italic">Alouatta palliata</Emphasis> in Oaxaca,Mexico

Primate conservation requires a better knowledge of the distributions and statuses of populations in both large areas of habitat and in areas for which we currently have no information. We focused on spider monkeys (Ateles geoffroyi) and howler monkeys (Alouatta palliata) in the state of Oaxaca, Mexico. This Mexican state has protected large tracts of forest, and has historical records for both primates, although very little is known about them. To update our knowledge of the distributions of these primates and identify potential areas in which they are present, we modeled their geographic distributions by characterizing their ecological niches using the genetic algorithm for rule-set production (GARP), performed interviews and carried out field surveys. The predicted distributions, surveys and interviews indicate that the distributions of these primates are restricted to northeastern Oaxaca. The results suggest that spider monkeys occupy a wider area and elevational range than howler monkeys. Throughout that range there is a wide variety of suitable habitats for these primates. Most of the sites where monkeys were recorded in the field are not officially protected and there was evidence of hunting and habitat destruction. It is important to improve protection, economic alternatives and environmental education as we move towards an integral solution for the conservation of these species. Validation of the GARP model was done for A. geoffroyi, since we had obtained enough field data for this species; this validation indicated that the predicted distribution of the species was statistically better than expected by chance. Hence, ecological niche modeling is a useful approach when performing an initial assessment to identify distribution patterns, detecting suitable areas for future exploration, and for conservation planning. Our findings provide an improved basis for primate conservation and productive fieldwork in Oaxaca.     

Predicted range expansion of the invasive plant <Emphasis Type="Italic">Leucaena leucocephala</Emphasis> in the Hengchun peninsula,Taiwan

We integrated correlative (species distribution) and process-based (agent-based) modeling approaches—to predict future range expansion of an invasive plant (Leucaena leucocephala) in the lowland rainforest and tropical coastal forest ecosystems of the Hengchun peninsula, Taiwan. We simulated range expansion to the year 2027 using a spatially-explicit, agent-based model representing invasion rate as a function of habitat quality and propagule pressure. We developed an index of habitat quality by relating 1988 plant distribution data to geo-referenced data on climatic conditions, landscape features, and anthropogenic factors via logistic regression. We represented propagule pressure using a lognormal dispersal kernel. We evaluated model performance by simulating range expansion from 1988 to 2007 and comparing simulated distribution patterns to those observed in 2007. Results of logistic regression indicated that L. leucocephala is more likely to occur in warm, dry areas containing a higher percentage of natural landscape (forest or grassland), areas adjacent to the forest edge, and areas disturbed by human activities such as a main road or an abandoned sisal plantation. Model evaluation showed that the prediction performance is excellent with AUC > 0.9 and Mantel’s r = 0.77. Our results indicated that L. leucocephala will continue from the western portion toward the southern and central portions of Checheng township, and throughout the southern portion of Hengchun and Manjhou townships, with about 2500 ha of new area invaded within the next 20 years. Our predictions should allow managers to develop proactive management plans for the areas most likely to be invaded.     

Tree community structure reflects niche segregation of three parapatric squirrel monkey species (<Emphasis Type="Italic">Saimiri</Emphasis> spp.)

Integration between ecology and biogeography provides insights into how niche specialization affects the geographical distribution of species. Given that rivers are not effective barriers to dispersal in three parapatric species of squirrel monkeys (Saimiri vanzolinii, S. cassiquiarensis and S. macrodon) inhabiting floodplain forests of Central Amazonia, we tested whether forest structure and tree diversity may explain species differences in niche specialization and spatial segregation. We sampled 6617 trees of 326 species in three habitats (high várzea, low várzea and chavascal) used by three Saimiri species, and estimated tree species richness in each of them. For each tree, we measured variables known to influence habitat use in primates, such as crown area and presence of lianas, epiphytes and hemi-epiphytes. We used ANOVA to compare these variables and performed multivariate analyses (NMDS, ANOSIM and SIMPER) to evaluate dissimilarities in forest structure among each habitat inhabited by the three Saimiri species. We identified differences in the tree species richness, crown area and presence of lianas, epiphytes and hemi-epiphytes between the three habitats for all Saimiri species. NMDS demonstrated that areas of high and low várzeas occupied by S. vanzolinii were clearly separated from the other species. We also found that different plant species contributed to dissimilarity among Saimiri ranges. Our findings support the hypothesis that tree community structure may promote niche specialization and spatial segregation among primates. We discuss how these patterns could have been favored by historical changes in forest flood patterns, the evolutionary history of Saimiri spp., and past competition.     

Distribution and habitats of <Emphasis Type="Italic">Phengaris</Emphasis> (<Emphasis Type="Italic">Maculinea</Emphasis>) butterflies and population ecology of <Emphasis Type="Italic">Phengaris</Emphasis><Emphasis Type="Italic">teleius</Emphasis> in China

Many species of the butterfly genus Phengaris are regarded as endangered in many parts of their distribution. Several species are also widely distributed across northern China. Due to land use change and overgrazing, their habitats are declining and many patches have been lost. This paper investigates the distribution and habitats of the Chinese Phengaris species (of the subgenus Maculinea). Shrub-grassland near forests seem the most frequent habitat for Phengaris, while flat open grasslands are mostly over-grazed and thus survival for Phengaris butterflies there seems difficult. Throughout Europe, P. teleius is an endangered species, while there is still no information on its status in China. To improve the knowledge on the population ecology of P. teleius, its population structure, adult behaviour and movement were studied through mark–release–recapture methods in the Qinling Mountains of Taibai County. Eight grassland patches which were potentially suitable were found in the area in 2013. In total, 480 individuals (274 females) were marked, resulting in an overall recapture rate of 16 %. The average daily population size was 44 butterflies (±23 SD) during the adult flight period. Sixty-seven percent of the females and 38 % of the males moved less than 50 m, and 17 % of recaptured females and 38 % of males moved more than 200 m. The mean movement distance was 107 ± 177 m for males and 182 ± 122 m for females. The majority of the recaptures (86 %) were made within the patches, only a few individuals (14 %) moved between patches. Due to human disturbance and destruction, all of the eight potentially suitable patches are becoming smaller and increasingly isolated, thus these populations of P. teleius may face an increasing risk of extinction, which may well be a tip of the iceberg of habitat loss and fragmentation of P. teleius in Taibai County and possibly beyond. Hence we hope our initial study of P. teleius could have positive impacts on the conservation of Phengaris butterflies in China.     

Distributional and ecophysiological study on the Antarctic lichens species pair <Emphasis Type="Italic">Usnea antarctica</Emphasis>/<Emphasis Type="Italic">Usnea aurantiaco</Emphasis>-<Emphasis Type="Italic">atra</Emphasis>

The factors that control lichen distribution in Antarctica are still not well understood, and in this investigation we focused on the distribution, local and continental, and gas exchange of a species pair, closely related lichens with differing reproductive strategies, Usnea aurantiaco-atra (fertile) and Usnea antarctica (sterile, sorediate). The local distributions of these species were recorded along an altitudinal gradient of nearly 300 m at South Bay, Livingston Island, and microclimate was also recorded over 1 year. The photosynthetic responses to temperature, light and thallus water content were determined under controlled conditions in the laboratory. The species were almost identical in their photosynthetic profiles. Locally, on Livingston Island, U. antarctica was confined to low altitude sites which were warmer and drier, whilst U. aurantiaco-atra was present at all altitudes. This contrasts with its distribution across Antarctica where U. antarctica grows 9° latitude further south than U. aurantiaco-atra. Temperature appears not to be the main controller of distribution in these species, but dryness of habitat, which will influence length of activity periods, may be important.     

Boreal forest titans do not clash: low overlap in winter habitat selection by moose (<Emphasis Type="Italic">Alces americanus</Emphasis>) and reintroduced bison (<Emphasis Type="Italic">Bison bison</Emphasis>)

Despite moose (Alces americanus) likely being both an ecological and cultural keystone species in the North American boreal forest, few studies have examined niche overlap between moose and other ungulates. In response to concerns from local people about the potential for competition for habitat between moose and reintroduced bison (Bison bison), and the potential for disturbance to moose by bison and bison hunters, we investigated overlap in winter habitat selection by these species in southwestern Yukon, Canada. We used available geo-referenced data of animal locations, and associated environmental covariates, to develop resource selection probability function (RSPF) models of early-winter and late-winter habitat selection by moose and bison. In early-winter, moose selected sub-alpine shrub-dominated habitats, whereas bison extensively selected wet sedge meadows in lowland valleys. Both species used a greater variety of habitats in late-winter, with moose selecting drainages above tree line or river valleys with deciduous forest cover, while bison selected either south-facing grassy slopes or wet sedge meadows. Given observed differences in seasonal habitat selection between moose and bison, these species are predicted to overlap on only 0.5 and 6.6% of our 12,818-km² study area during early-winter and late-winter, respectively. The lack of demonstrated winter habitat overlap between moose and reintroduced bison, coupled with low diet overlap, points to an overall low potential for competition for winter habitat between these species, or for disturbance to moose attributable to bison or bison hunters. Resource partitioning that facilitates coexistence on a shared landscape suggests that concern over the impact of reintroduced bison on resident populations of moose is likely unwarranted.     

Endophytic yeasts in <Emphasis Type="Italic">Malus domestica</Emphasis> and <Emphasis Type="Italic">Pyrus communis</Emphasis> fruits under anthropogenic impact

Yeast abundance and species diversity on the surface and in inner tissues of Malus domestica and Pyrus communis fruits under high anthropogenic impact in the city of Moscow (Russia) were studied. Results demonstrated that abundance of epiphytic yeasts on the fruits increased gradually, reaching the maximum of 3.2 × 10⁴ CFU/g on mature fruits. During summer, abundance of endophytes did not change significantly (variation near 2.5 × 10³ CFU/g) until complete maturation, while in September their numbers increased to 10⁴ CFU/g. Basidiomycetous yeasts (Filobasidium wieringae, F. magnum, Rhodotorula glutinis, and Rhodosporidiobolus colostri) predominated on the fruit surface. Ascomycetous species were the most diverse group inside the fruits, which quantitatively increased through maturation. It was found that the share of opportunistic species Candida parapsilosis in internal tissues was significant during the entire period of fruit formation and development under anthropogenic impact in the city. Specific properties of epiphytic and endophytic yeast communities developing in natural ecological niches under synanthropic conditions and anthropogenic impact are discussed.     

The ecology of <Emphasis Type="Italic">Altrichthys azurelineatus</Emphasis> and <Emphasis Type="Italic">A. curatus,</Emphasis> two damselfishes that lack a pelagic larval phase

Out of more than 380 species of damselfish, only three lack a pelagic larval phase, Acanthochromis polyacanthus, that ranges from the Philippines to the Great Barrier Reef, and two species in the genus Altrichthys, A. azurelineatus and A. curatus, that are restricted to the Calamian Archipelago (Palawan province) in the Philippines. Therefore in a very restricted geographic area, northern Palawan, Philippines, all three species co-occur. The goal of this study was to fill a knowledge gap about the ecology of Altrichthys, where very little is currently known. Using census and behavioral approaches at 14 sites on six islands, we were able to identify adult densities, nest densities, nesting habitat preference, and brood behavior and abundance. We found that densities were very high (more than 17 individuals/100 m² for one species) and A. azurelineatus may be displacing A. curatus at deeper depths where habitat seems of higher quality. Only one out of 14 surveyed sites contained only one species, Altrichthys curatus. Different habitat use and feeding behavior suggest that niche partitioning may play an important role in the life history of these sympatric species.     

Climatic niche evolution in the Andean genus <Emphasis Type="Italic">Menonvillea</Emphasis> (Cremolobeae: Brassicaceae)

The study of how climatic niches change over evolutionary time has recently attracted the interest of many researchers. Different methodologies have been employed principally to analyze the temporal dynamics of the niche and specially to test for the presence of phylogenetic niche conservatism. Menonvillea, a genus of Brassicaceae including 24 species, is distributed primarily along the Andes of Argentina and Chile, with some taxa growing in southern Patagonia and others in the Atacama Desert and the Chilean Matorral. The genus is highly diversified morphologically but also presents a remarkably wide ecological range, growing from the high Andean elevations, to the dry coastal deserts in Chile, or the Patagonia Steppe in Argentina. In this study, we used molecular phylogenies together with climatic data to study climatic niche evolution in the genus. The results show that the main climatic niche shifts in Menonvillea occurred between the sections Cuneata-Scapigera and sect. Menonvillea throughout the Mid-Late Miocene, and associated with the two main geographical distribution centers of the genus: the highlands of the central-southern Andes and the Atacama Desert-Chilean Matorral, respectively. Climatic niches in these lineages were mainly differentiated by the aridity and potential evapotranspiration, the minimum temperatures of the coldest month, and the temperature annual range and seasonality. Niche evolution in Menonvillea deviated from a Brownian motion process, with most of the climatic dimension best-fitting to an Ornstein-Uhlenbeck model of multiple adaptive peaks. Our results also indicated that higher aridity levels and lower annual temperature ranges were associated with the evolution of the annual habit, as exemplified by the distribution of sect. Menonvillea. Finally, the results suggested that climatic niche evolution in Menonvillea exhibited some degree of phylogenetic niche conservatism, fundamentally within the two main lineages (sect. Menonvillea and sects. Cuneata-Scapigera).     

Establishment of <Emphasis Type="Italic">Anolis sagrei</Emphasis> on Bermuda represents a novel ecological threat to Critically Endangered Bermuda skinks (<Emphasis Type="Italic">Plestiodon longirostris</Emphasis>)

Bermuda is an isolated, oceanic island with only one endemic terrestrial vertebrate, the Critically Endangered Bermuda skink (Plestiodon longirostris; Squamata, Scincidae). Major declines in P. longirostris populations have been caused primarily by habitat loss and mortality via invasive species (e.g., predation from birds and cats) and human waste products (e.g., trapped in discarded bottles). However, biotic interactions and interspecific competition with invasive lizards have also been identified as potentially detrimental to P. longisrostris populations. Here, we provide the first occurrence records of a highly invasive lizard, the Cuban brown anole (Anolis sagrei), on Bermuda. We assess the brown anole’s diet, habitat use, morphology, and island-wide distribution for comparison to the native skink, P. longirostris. Results of this study indicate that A. sagrei in Bermuda are highly terrestrial (>60% of all lizards observed on the ground vs. in trees) and forage primarily on terrestrial invertebrates. These data indicate substantial ecological overlap with the exclusively-terrestrial P. longirostris. This is in contrast to the other established non-native lizards on Bermuda, which are principally arboreal and have successfully coexisted with P. longirostris for >60 years. At present, the geographic distributions of A. sagrei and P. longirostris do not overlap. However, all extant skink populations are within several kilometers of brown anole populations (with the nearest being <0.5 km). The extensive overlap in ecological niche between the Bermuda skink and the invasive brown anole will likely present a serious conservation threat if contact is made. This study is exceptional in providing clear in situ ecological data which predict a conservation threat of an established invasive species to a Critically Endangered island endemic prior to coexistence. Continued monitoring of this situation as P. longirostris and A. sagrei inevitably come into contact will allow these a priori hypotheses of conservation risk via ecological overlap to be tested.     

Co-invasion of three Asian earthworms, <Emphasis Type="Italic">Metaphire hilgendorfi</Emphasis>, <Emphasis Type="Italic">Amynthas agrestis</Emphasis> and <Emphasis Type="Italic">Amynthas tokioensis</Emphasis> in the USA

Earthworm invasions are one of the most serious causes of ecological deterioration in the temperate deciduous forests of North America. Non-native earthworms impact understory vegetation, leaf litter layer, carbon dynamics, nutrient availability, and the associated food webs. Here we report a significant status change and confirm expansion of known range of Amynthas agrestis, one of the most serious invasive species in North America, and two of its close relatives, A. tokioensis and Metaphire hilgendorfi. The three species have never been confirmed to co-occur in North American ecosystems. We examined 1760 earthworms collected from 30 sites across northeastern USA, and identified them using a new morphological key. Our data show that sympatric occurrence of at least two, and often all three, species is more common than having only one species. In addition, A. tokioensis was dominant in many of these earthworm communities. The status change in species composition from only one species to two or three and the shift in dominance are most likely caused by previous incorrect species identification. Our results support expansion of known range of A. tokioensis and M. hilgendorfi northward and westward into states with colder winters. This range expansion may have taken place alongside that of A. agrestis in the last 10–20 years, but has long been overlooked. Altogether, results highlight an urgent need for correct species identification. The recognition of an expanding multi-species system represents a unique opportunity to further evaluate complex interactions among co-invading and resident species, and to investigate whether interspecific interactions have unexpected non-additive impacts on ecological processes.     

Food resource partitioning of the <Emphasis Type="Italic">Mustelus lunulatus</Emphasis> and <Emphasis Type="Italic">Mustelus henlei</Emphasis> (Elasmobranchii: Carcharhiniformes)

The feeding habits and trophic ecology of Mustelus lunulatus and Mustelus henlei in the central coast of the Colombian Pacific were evaluated and compared to determine whether there was trophic niche overlap or resource partitioning between these two sympatric shark species. A total of 59 prey items were identified and grouped into 10 taxonomic categories. Mustelus lunulatus fed in large proportion on Stomatopoda and Brachyura, whereas M. henlei fed almost exclusively on Teleostei. Dendrobranchiata, Cephalopoda, Anomura and Polychaeta complemented the diets of both species. There were significant differences in diet between the two species, and there was an ontogenetic diet shift in Mustelus lunulatus, with Stomatopoda being the main prey item of juveniles and Brachyura the main prey item of adults. Dietary overlap (by sex and size) was low between species, but it was high for each species, with significant overlap between juveniles and adults of M. lunulatus and M. henlei, and between males and females of M. henlei. There were differences in the trophic levels of the species, sexes and sizes. This study suggests there is food resource partitioning, and differing ecological function of the two Mustelus species in the food web of the study area.