Differences In Habitat Use Research Articles

Home ranges, habitat and body mass: simple correlates of home range size in ungulates.

The spatial scale of animal space use, e.g. measured as individual home range size, is a key trait with important implications for ecological and evolutionary processes as well as management and conservation of populations and ecosystems. Explaining variation in home range size has therefore received great attention in ecological research. However, few studies have examined multiple hypotheses simultaneously, which is important provided the complex interactions between life history, social system and behaviour. Here, we review previous studies on home range size in ungulates, supplementing with a meta-analysis, to assess how differences in habitat use and species characteristics affect the relationship between body mass and home range size. Habitat type was the main factor explaining interspecific differences in home range size after accounting for species body mass and group size. Species using open habitats had larger home ranges for a given body mass than species using closed habitats, whereas species in open habitats showed a much weaker allometric relationship compared with species living in closed habitats. We found no support for relationships between home range size and species diet or mating system, or any sexual differences. These patterns suggest that the spatial scale of animal movement mainly is a combined effect of body mass, group size and the landscape structure. Accordingly, landscape management must acknowledge the influence of spatial distribution of habitat types on animal behaviour to ensure natural processes affecting demography and viability of ungulate populations.

Does social context affect boldness in juveniles?

Differences in boldness are common between populations or between related species and are discussed as part of individual coping style, personality, or behavioral syndrome. Boldness has been found to be dependent on experience, social, and environmental contexts. The major aim of the present study was to establish an experimental environment that would allow analyzing the risk-taking behavior of 2 competing invasive goby species. Neogobius melanostomus was more active in the absence of a predator Sander lucioperca than N. fluviatilis and clearly spent more time “swimming” and “feeding” than N. fluviatilis. In addition, N. melanostomus was always faster than N. fluviatilis both when leaving the shelter and reaching offered food. Based on the different behaviors recorded, species-specific boldness scores were established using a principal component analysis. Although there was no overall difference in boldness scores between the 2 species, both competitive conditions and the effect of the predator played significant roles as factors influencing boldness. Neogobius melanostomus was more affected by the presence/absence of the predator than the social circumstances. Neogobius fluviatilis, on the other hand, was more active and bolder in competitive situations. However, when alone, N. fluviatilis was rather inactive and displayed altogether shy behavior, independent of the presence/absence of the predator. Thus, the study confirms the prediction that there are differences in behavior and behavioral plasticity, and therein predator-avoidance strategies, between ecologically similar species of goby living in sympatry. We argue that these differences may be related to differential habitat use of both invasive species that presently dominate the fish community in the Lower Rhine.

Understanding Peripheral Bat Populations Using Maximum-Entropy Suitability Modeling.

Individuals along the periphery of a species distribution regularly encounter more challenging environmental and climatic conditions than conspecifics near the center of the distribution. Due to these potential constraints, individuals in peripheral margins are expected to change their habitat and behavioral characteristics. Managers typically rely on species distribution maps when developing adequate management practices. However, these range maps are often too simplistic and do not provide adequate information as to what fine-scale biotic and abiotic factors are driving a species occurrence. In the last decade, habitat suitability modelling has become widely used as a substitute for simplistic distribution mapping which allows regional managers the ability to fine-tune management resources. The objectives of this study were to use maximum-entropy modeling to produce habitat suitability models for seven species that have a peripheral margin intersecting the state of North Dakota, according to current IUCN distributions, and determine the vegetative and climatic characteristics driving these models. Mistnetting resulted in the documentation of five species outside the IUCN distribution in North Dakota, indicating that current range maps for North Dakota, and potentially the northern Great Plains, are in need of update. Maximum-entropy modeling showed that temperature and not precipitation were the variables most important for model production. This fine-scale result highlights the importance of habitat suitability modelling as this information cannot be extracted from distribution maps. Our results provide baseline information needed for future research about how and why individuals residing in the peripheral margins of a species’ distribution may show marked differences in habitat use as a result of urban expansion, habitat loss, and climate change compared to more centralized populations.

Spatial and Temporal Distinction of Microelemental Signatures of Missouri River Tributaries

AbstractThe microchemical composition of a fish's calcified structure, such as an otolith, fin ray, or scale, is a ‘biological tag’ that reflects the use of different habitats throughout its life history. Hard‐part microchemistry has the potential to address many fish conservation, management, and behavior questions. In order to use hard‐part microchemistry to address fisheries research questions, elemental signatures of water must be distinct at the spatial scale of interest and ideally temporally stable. The goal of this study was to assess whether spatial differences existed in the concentrations of five elements [barium (137Ba), magnesium (24Mg), manganese (55Mn), sodium (23Na), and strontium (88Sr)] between and within eight Missouri River tributaries and whether those signatures were temporally stable. All elemental concentrations were converted to molar ratios (mmol mol−1) using calcium (43Ca) concentrations as the base. Canonical correspondence analysis showed distinct differences in Mg:Ca, Na:Ca, and Sr:Ca concentrations between the eight tributaries. Cochran–Mantel–Haenszel tests showed that sites within a tributary were distinguished using Mg:Ca and Na:Ca concentrations. However, only Mg:Ca concentrations were temporally stable. Results from this study demonstrate the potential for using hard‐part microchemistry to address various questions at multiple spatial scales in the Missouri River riverscape but also highlight the importance of evaluating water microelemental signatures prior or simultaneous to any hard‐part microchemistry study. Copyright © 2016 John Wiley & Sons, Ltd.

Testing a Habitat Suitability Index Model for Boreal Owls in Western Newfoundland, Canada

Boreal Owls (Aegolius funereus) rely on mature forests and, consequently, are negatively affected by timber harvesting strategies that alter the composition and structure of these forests. We tested an existing Boreal Owl habitat suitability index (HSI) model created using data from across the species' North American breeding distribution, plus a modified Newfoundland version that incorporated local data. We assessed the applicability of these models to a population on the periphery of the species' North American range in Newfoundland, Canada. We also conducted habitat composition analyses and evaluated the Boreal Owl HSI model values associated with forest cover projections under three different forest harvesting scenarios. Overall output from both HSI models indicated low levels of suitability for locations across the study area. Long-term persistence in Newfoundland demonstrates that suitable habitat for Boreal Owls exists, but what constitutes suitable habitat for populations in other parts of North America may differ from that in our study area. Boreal Owls in Newfoundland occupied locations with a greater proportion of disturbed cover, and lesser proportions of deciduous and mixed coniferous and deciduous stands ≥60 yr old, compared to what was available in the surrounding region, as measured in randomly selected plots. Whereas Boreal Owl habitat use in Newfoundland was similar to that described for other populations, the limited use of deciduous and mixed stands was distinct. Forward projection modeling of forest cover indicated that there were no differences in the overall suitability of habitat available to Boreal Owls under the three harvesting scenarios. Our study highlights the importance of adjusting forest management strategies to account for differences in habitat use among populations.

Estimating density of a territorial species in a dynamic landscape

Conservation planning for at-risk species requires understanding of where species are likely to occur, how many individuals are likely to be supported on a given landscape, and the ability to monitor those changes through time. We developed a distribution model for northern spotted owls that incorporates both habitat suitability and probability of territory occupancy while accounting for interspecies competition. We developed range-wide habitat suitability maps for two time periods (1993 and 2012) for northern spotted owls that accounted for regional differences in habitat use and home range size. We used these maps for a long-term demographic monitoring study area to assess habitat change and estimate the number of potential territories based on available habitat for both time periods. We adjusted the number of potential territories using known occupancy rates to estimate owl densities for both time periods. We evaluated our range-wide habitat suitability model using independent survey data. Our range-wide habitat maps predicted areas suitable for territorial spotted owl presence well. On the demographic study area, the amount of habitat declined 19.7% between 1993 and 2012, while our estimate of the habitat-based carrying capacity declined from 150 to 146 territories. Estimated number of occupied territories declined from 94 to 57. Conservation and recovery of at-risk species depends on understanding how habitat changes over time in response to factors such as wildfire, climate change, biological invasions, and interspecies competition, and how these changes influence species distribution. We demonstrate a model-based approach that provides an effective planning tool.

Seasonal changes in habitat selection by a strict forest specialist, the Middle Spotted Woodpecker (Leiopicus medius), at its southwestern boundary: implications for conservation

The Middle Spotted Woodpecker (Leiopicus medius) is a strict forest bird whose habitat preferences during the breeding season are well known. However, a lack of information about its habitat selection during the non-breeding season may hamper recommendations for the management and conservation of the species. Here we study habitat selection of this woodpecker at its southwestern boundary range (Izki Natural Park, northern Spain) during the non-breeding season (October–December) by means of a use–availability approach. We also examined seasonal differences in habitat use between the breeding season (April–May) and the non-breeding season. Results of ANOVA and backward-stepwise logistic regression revealed a clear selection of high forest cover, large Pyrenean oaks (Quercus pyrenaica), and presence of dead trees during the non-breeding season. Despite very similar habitat use in both seasons, minor but interesting differences between seasons were observed, with a potential expansion during the non-breeding season into less mature forests (lower forest cover and fewer large trees) with a greater abundance of dead trees. These differences may reflect seasonal changes in the spatial requirements of the species and a decrease in food abundance during autumn–winter. On the basis of these findings, we propose management measures to improve the conservation status of the species in the Iberian Peninsula.

Understory algae associations and predation risk influence broad-scale kelp habitat use in a temperate reef fish

MEPS Marine Ecology Progress Series Contact the journal Facebook Twitter RSS Mailing List Subscribe to our mailing list via Mailchimp HomeLatest VolumeAbout the JournalEditorsTheme Sections MEPS 559:147-158 (2016) - DOI: https://doi.org/10.3354/meps11892 Understory algae associations and predation risk influence broad-scale kelp habitat use in a temperate reef fish Alejandro Pérez-Matus1,*, Fernando Sánchez1, Juan C. González-But1, Robert W. Lamb2 1Subtidal Ecology Laboratory and Center for Marine Conservation, Estación Costera de Investigaciones Marinas, Facultad de Ciencias Biológicas, Pontificia Universidad Católica de Chile, Casilla 114-D, Santiago, Chile 2Department of Ecology and Evolutionary Biology, Brown University, Providence, Rhode Island 02912, USA *Corresponding author: aperez@bio.puc.cl ABSTRACT: Habitat selection and predation are ecological processes that operate at small spatial scales. How these influence large-scale patterns in abundance and distribution of fauna remains to be resolved, especially in structurally complex systems such as kelp beds. In order to explain whether habitat selection, differential predation, or a combination of factors explain variation in fish abundance among sites, we conducted field surveys of abundance and microhabitat use of a temperate reef fish (Tripterygiidae, Helcogrammoides cunninghami Smitt, 1898) at sites of varying kelp cover and different understory algal assemblages. We observed variation in abundance among sites and, particularly, that sites with abundant kelp individuals have 4 times fewer fish. In order to explain these differences in habitat use and variation in abundance among sites, we conducted choice chamber experiments in the laboratory and tethering experiments in the field. In the laboratory, individuals tend to discriminate among options by selecting substrata with understory biogenic habitat (i.e. filamentous algae) and avoiding kelp. Finally, tethering experiments in the field evaluating H. cunninghami mortality rates in preferred habitat types compared to kelp beds confirmed an increase in predator richness and a 2-fold increase in predation rates inside kelp habitats. Together, these results suggest that multiple mechanisms that operate mainly at small spatial scales (predation and habitat selection) may influence the distribution and abundance of organisms over large areas. KEY WORDS: Reef fish · Kelp forest · Habitat selection · Mortality rates Full text in pdf format Supplementary material PreviousNextCite this article as: Pérez-Matus A, Sánchez F, González-But JC, Lamb RW (2016) Understory algae associations and predation risk influence broad-scale kelp habitat use in a temperate reef fish. Mar Ecol Prog Ser 559:147-158. https://doi.org/10.3354/meps11892 Export citation RSS - Facebook - Tweet - linkedIn Cited by Published in MEPS Vol. 559. Online publication date: November 09, 2016 Print ISSN: 0171-8630; Online ISSN: 1616-1599 Copyright © 2016 Inter-Research.

Challenge to the model of lake charr evolution: shallow- and deep-water morphs exist within a small postglacial lake

All examples of lake charr (Salvelinus namaycush) diversity occur within the largest, deepest lakes of North America (i.e. > 2000 km2). We report here Rush Lake (1.3 km2) as the first example of a small lake with two lake charr morphs (lean and huronicus). Morphology, diet, life history, and genetics were examined to demonstrate the existence of morphs and determine the potential influence of evolutionary processes that led to their formation or maintenance. Results showed that the huronicus morph, caught in deep-water, had a deeper body, smaller head and jaws, higher eye position, greater buoyancy, and deeper peduncle than the shallow-water lean morph. Huronicus grew slower to a smaller adult size, and had an older mean age than the lean morph. Genetic comparisons showed low genetic divergence between morphs, indicating incomplete reproductive isolation. Phenotypic plasticity and differences in habitat use between deep and shallow waters associated with variation in foraging opportunities seems to have been sufficient to maintain the two morphs, demonstrating their important roles in resource polymorphism. Rush Lake expands previous explanations for lake charr intraspecific diversity, from large to small lakes and from reproductive isolation to the presence of gene flow associated with strong ecological drivers.

Habitat use and preference of adult pike (Esox lucius L.) in an anthropogenically impacted lowland river

To efficiently manage northern pike ( Esox lucius ), information is needed on its habitat use and preference. However, knowledge gaps still exist, especially on pike habitat use and preference in rivers characterised by artificial environments. We investigated the use of the main river, tributaries and side arms at the macro-scale, and the use and preference of riparian habitats by adult pike at the meso-scale in an anthropogenically impacted river basin. Adult pike were followed in winter and spring by radio telemetry. At the macro-scale pike intensively used the main river in winter and spring, but also frequented specific side arms in winter and specific tributaries in spring, which may indicate the importance of these habitats to adult pike. At the meso-scale, reedy semi-natural banks were used the most, irrespective of any assumption on habitat availability or use. The findings underline the value of protecting the least impacted, (semi)natural habitats for adult pike in an anthropogenically impacted river system. The large behavioural differences in habitat use between individuals at both habitat scales further underline the importance of habitat heterogeneity. The results also provide insight into the impact of riparian habitat restoration on adult pike and may be used to more efficiently manage pike rivers, e.g. by enhancing the lateral connectivity with river side arms or by reconstructing natural riparian habitats.

Home ranges of parthenogenetic and bisexual species in a community of Darevskia lizards (Reptilia: Lacertidae)

We analysed the home ranges of a community of Darevskia rock lizards composed of a bisexual species (D. valentini), two parthenogens (D. armeniaca and D. unisexualis), and two backcross forms between bisexual and unisexual forms. We estimated home range areas of ink-marked, GPS-located lizards using Minimum Convex Polygon (MCP) and 95% of the locations for those individuals with five or more sightings. The bisexual D. valentini was the species with the largest home ranges, distances travelled, and the most intersections. No differences between unisexual species and backcrosses were recorded for any comparison. In males, home range size and perimeter were related to morphological characteristics. Contrary to what has been described in allopatry, unisexual species showed smaller home ranges and fewer overlaps than sympatric bisexual species. We tentatively suggest that the presence of potential bisexual partners might increase sexual competition among parthenogenetic females while differences in habitat use should also be considered.

Does adaptive radiation of a host lineage promote ecological diversity of its bacterial communities? A test using gut microbiota of Anolis lizards.

Adaptive radiations provide unique opportunities to test whether and how recent ecological and evolutionary diversification of host species structures the composition of entire bacterial communities. We used 16S rRNA gene sequencing of faecal samples to test for differences in the gut microbiota of six species of Puerto Rican Anolis lizards characterized by the evolution of distinct 'ecomorphs' related to differences in habitat use. We found substantial variation in the composition of the microbiota within each species and ecomorph (trunk-crown, trunk-ground, grass-bush), but no differences in bacterial alpha diversity among species or ecomorphs. Beta diversity analyses revealed subtle but significant differences in bacterial composition related to host phylogeny and species, but these differences were not consistently associated with Anolis ecomorph. Comparison of a trunk-ground species from this clade (A.cristatellus) with a distantly related member of the same ecomorph class (A.sagrei) where the two species have been introduced and are now sympatric in Florida revealed pronounced differences in the alpha diversity and beta diversity of their microbiota despite their ecological similarity. Comparisons of these populations with allopatric conspecifics also revealed geographic differences in bacterial alpha diversity and beta diversity within each species. Finally, we observed high intraindividual variation over time and strong effects of a simplified laboratory diet on the microbiota of A.sagrei. Collectively, our results indicate that bacterial communities are only weakly shaped by the diversification of their lizard hosts due to the strikingly high levels of bacterial diversity and variation observed within Anolis species.

Pronounced inter-colony variation in the foraging ecology of Australasian gannets: influence of habitat differences

MEPS Marine Ecology Progress Series Contact the journal Facebook Twitter RSS Mailing List Subscribe to our mailing list via Mailchimp HomeLatest VolumeAbout the JournalEditorsTheme Sections MEPS 556:261-272 (2016) - DOI: https://doi.org/10.3354/meps11845 Pronounced inter-colony variation in the foraging ecology of Australasian gannets: influence of habitat differences Lauren P. Angel*, Maud Berlincourt, John P. Y. Arnould School of Life and Environmental Sciences (Burwood campus), Deakin University, Geelong, Victoria 3216, Australia *Corresponding author: lauren.angel@deakin.edu.au ABSTRACT: The predictability of prey due to oceanographic features can result in large aggregations of apex predators. Central place foragers, such as seabirds, are limited in their foraging duration and range during the breeding period, which can restrict their ability to reach such locations. Segregation by colony and sex can further restrict foraging range and may have direct implications for the foraging ecology of a species. In parts of its range, the Australasian gannet Morus serrator breeds in colonies of relatively close proximity and has recently been found to display sexual dimorphism. Two neighbouring breeding colonies in Bass Strait that experience divergent environmental conditions were investigated to determine whether these conditions or the sex of the individual are important variables influencing foraging behaviour in this species. GPS tracking and accelerometry were paired with stable isotope analysis to compare differences in foraging effort, habitat use and diet. Birds from Point Danger, a large colony located near a seasonally strong upwelling, travelled considerably further (77%) than birds from Pope’s Eye, a small colony in a nutrient-poor embayment. However, within colonies no sexual differences in foraging effort were found. While the colonies did not overlap in foraging areas, a degree of sexual segregation was apparent within both colonies (Point Danger 46.3% overlap and Pope’s Eye 73.7% overlap in home range). Furthermore, stable isotope analysis indicated birds from each colony fed at different trophic niches. This study reveals differences in habitat use and, consequently, dietary niches between and within neighbouring colonies. KEY WORDS: Foraging ecology · GPS tracking · Accelerometry · Stable isotopes · Sexual‑segregation · Morus serrator Full text in pdf format PreviousNextCite this article as: Angel LP, Berlincourt M, Arnould JPY (2016) Pronounced inter-colony variation in the foraging ecology of Australasian gannets: influence of habitat differences. Mar Ecol Prog Ser 556:261-272. https://doi.org/10.3354/meps11845 Export citation RSS - Facebook - Tweet - linkedIn Cited by Published in MEPS Vol. 556. Online publication date: September 08, 2016 Print ISSN: 0171-8630; Online ISSN: 1616-1599 Copyright © 2016 Inter-Research.

Building time-budgets from bioacoustic signals to measure population-level changes in behavior: a case study with sperm whales in the Gulf of Mexico

Evaluating changes in the collective behavior of a population can be an indirect method for inferring organismal responses to changing environmental conditions. Apex predators, such as the sperm whale (Physeter macrocephalus), can provide valuable insights into the ecosystem processes of the deep sea, where little direct observation can be made. Sperm whales are often difficult to observe at sea, as they inhabit deep, offshore waters and spend most of their lives beneath the surface. However, sperm whales are extremely amenable to passive acoustic monitoring, as their vocalizations are well-studied, highly distinguishable, produced regularly, and can be detected at relatively long ranges (>10km). Sperm whales produce distinct clicks in two behavioral contexts (social interaction or foraging/prey capture); thus, we can use acoustic detection of these vocalizations to infer patterns of large-scale, collective behavior, which is similar to studying calling frogs or insects indicating their reproductive phenology. We recorded behaviorally-specific sperm whale vocalizations at three sites in the Northern Gulf of Mexico in July 2010 and 2011. We used these recordings to construct population-level time budgets, an empirical collective metric of behavior, based on the ratio of hours in a day with social clicks to the hours in a day with foraging clicks, and represented this as an “acoustic activity index.” Our index showed significant differences in the proportions of social and foraging behavior across the range of sperm whales in the Northern Gulf of Mexico, and the proportion of social activity increased by more than a factor of two from 2010 to 2011. These differences support previous evidence of differential habitat use by sperm whales in the Gulf of Mexico, and suggest possible changes in environmental conditions between years. Thus, the acoustic activity index may provide a powerful way to evaluate changes in behavior and link them to changing ecological conditions. This novel application of bioacoustics to constructing time budgets and creating a behaviorally-based index at the population scale can serve as an indicator of ecological change, and greatly enhance our ability to understand the behavior and ecology of many acoustically active species.

Proximate drivers of spatial segregation in non-breeding albatrosses.

Many animals partition resources to avoid competition, and in colonially-breeding species this often leads to divergent space or habitat use. During the non-breeding season, foraging constraints are relaxed, yet the patterns and drivers of segregation both between and within populations are poorly understood. We modelled habitat preference to examine how extrinsic (habitat availability and intra-specific competition) and intrinsic factors (population, sex and breeding outcome) influence the distributions of non-breeding grey-headed albatrosses Thalassarche chrysostoma tracked from two major populations, South Georgia (Atlantic Ocean) and the Prince Edward Islands (Indian Ocean). Spatial segregation was greater than expected, reflecting distinct seasonal differences in habitat selection and accessibility, and avoidance of intra-specific competition with local breeders. Previously failed birds segregated spatially from successful birds during summer, when they used less productive waters, suggesting a link between breeding outcome and subsequent habitat selection. In contrast, we found weak evidence of sexual segregation, which did not reflect a difference in habitat use. Our results indicate that the large-scale spatial structuring of albatross distributions results from interactions between extrinsic and intrinsic factors, with important implications for population dynamics. As habitat preferences differed substantially between colonies, populations should be considered independently when identifying critical areas for protection.

Niche dynamics of shorebirds in Delaware Bay: Foraging behavior, habitat choice and migration timing

Niche differentiation through resource partitioning is seen as one of the most important mechanisms of diversity maintenance contributing to stable coexistence of different species within communities. In this study, I examined whether four species of migrating shorebirds, dunlins (Calidris alpina), semipalmated sandpipers (Calidris pusilla), least sandpipers (Calidris minutilla) and short-billed dowitchers (Limnodromus griseus), segregate by time of passage, habitat use and foraging behavior at their major stopover in Delaware Bay during spring migration. I tested the prediction that most of the separation between morphologically similar species will be achieved by differential migration timing. Despite the high level of overlap along observed niche dimensions, this study demonstrates a certain level of ecological separation between migrating shorebirds. The results of analyses suggest that differential timing of spring migration might be the most important dimension along which shorebird species segregate while at stopover in Delaware Bay. Besides differences in time of passage, species exhibited differences in habitat use, particularly least sandpipers that foraged in vegetated areas of tidal marshes more frequently than other species, as well as short-billed dowitchers that foraged in deeper water more often than small sandpipers did. Partitioning along foraging techniques was less prominent than segregation along temporal or microhabitat dimensions. Such ranking of niche dimensions emphasizes significance of temporal segregation of migratory species – separation of species by time of passage may reduce the opportunity for interspecific aggressive encounters, which in turn can have positive effects on birds' time and energy budget during stopover period.

Pinyon-juniper removal has long-term effects on mammals

Removing tree cover is a common forest management practice, and pinyon-juniper woodlands in the western United States have been the focus of tree reduction efforts for decades. The scale and intensity of tree removal practices are expected to increase as technology advances and as land managers are tasked with meeting multiple objectives, including fire prevention and habitat enhancement for livestock and wildlife of conservation concern. However, the long-term consequences of pinyon-juniper removal on animal communities are virtually unknown. The objectives of this study were to assess whether mammal habitat use differs between reference pinyon-juniper woodlands and stands that were mechanically disturbed by chaining more than 40years ago, and to determine if these differences are associated with particular habitat characteristics. We used remotely triggered wildlife cameras to evaluate differences in mammal habitat use of historically chained sites (n=22) and reference sites (n=22) in northwestern Colorado. Our results demonstrate marked differences in habitat use between chained sites and reference woodlands for most detected mammal species. Bobcat, mountain lion, American black bear, golden-mantled ground squirrel, and rock squirrel all showed a negative response to historically chained sites, indicating long-term effects of tree removal on these species. In contrast, habitat use of chipmunk, mountain cottontail, and coyote did not differ between chained and reference sites. For most species, habitat use was influenced by specific vegetation characteristics, such as proportion of tree cover, which could be factored into management decisions. By understanding the long-term consequences of tree removal for diverse mammal species, we are better equipped to adapt forest management practices to benefit species of both economic and conservation concern.

Incipient sympatric speciation in Midas cichlid fish from the youngest and one of the smallest crater lakes in Nicaragua due to differential use of the benthic and limnetic habitats?

Understanding how speciation can occur without geographic isolation remains a central objective in evolutionary biology. Generally, some form of disruptive selection and assortative mating are necessary for sympatric speciation to occur. Disruptive selection can arise from intraspecific competition for resources. If this competition leads to the differential use of habitats and variation in relevant traits is genetically determined, then assortative mating can be an automatic consequence (i.e., habitat isolation). In this study, we caught Midas cichlid fish from the limnetic (middle of the lake) and benthic (shore) habitats of Crater Lake Asososca Managua to test whether some of the necessary conditions for sympatric speciation due to intraspecific competition and habitat isolation are given. Lake As. Managua is very small (<900 m in diameter), extremely young (maximally 1245 years of age), and completely isolated. It is inhabited by, probably, only a single endemic species of Midas cichlids, Amphilophus tolteca. We found that fish from the limnetic habitat were more elongated than fish collected from the benthic habitat, as would be predicted from ecomorphological considerations. Stable isotope analyses confirmed that the former also exhibit a more limnetic lifestyle than the latter. Furthermore, split‐brood design experiments in the laboratory suggest that phenotypic plasticity is unlikely to explain much of the observed differences in body elongation that we observed in the field. Yet, neutral markers (microsatellites) did not reveal any genetic clustering in the population. Interestingly, demographic inferences based on RAD‐seq data suggest that the apparent lack of genetic differentiation at neutral markers could simply be due to a lack of time, as intraspecific competition may only have begun a few hundred generations ago.

Nesting habits of Centris (Hemisiella) dichrootricha (Hymenoptera: Apidae) in the Northern Cerrado of Brazil.

The Neotropical bee Centris (Hemisiella) dichrootricha is a solitary bee that nests in pre-existing cavities that occur in the rain forest. This study describes the nesting biology of C. dichrootricha and its preference for nesting in Cerrado and gallery forest habitats. The study was conducted from January 2012 and December 2013, in Mirador State Park in the municipality of Formosa da Serra Negra, Maranhão State, Brazil. For this, wooden trap-nests of 6, 8, 10, 12, 14 and 16 mm in diameter were used; a total of 300 trap-nests were placed in the gallery forest and Cerrado areas, respectively. Traps were monitored monthly and all completed nests were collected and replaced with empty ones. The nests were then taken to the laboratory to analyze bee development and emergence, nests characteristics and parasites presence. The species used 29 of the trap-nests, which had diameters of 8, 10, 12 and 14 mm. A total of 87 C. dichrootricha specimens emerged. The nests were parasitized by two bee species, Mesocheira bicolor (Apinae) and Coelioxys sp. (Megachilinae), and one fly species, Antrax sp. (Diptera). The highest nesting incidence of 72.4 % was observed in the gallery forest, whereas only 27.6 % in the Cerrado; this difference in habitat use was significant (χ² = 5.56; p < 0.05; DF = 1). For the nests that were built in the gallery forest, 80.9% of the soil originated from the Cerrado. The females were significantly larger than the males (F1, 76 = 595.19; p < 0.001). There were 11 pollen types that belonged to six families. Pollen of the family Malpighiaceae was most frequently used, with four species represented (Byrsonima crassifolia, B. rotunda, B. spicata and Heteropterys sp.). C. dichrootricha showed a preference for nesting in cavities of various diameters in gallery forest sites. The present study provides a novel description of the nesting habits and biology of C. dichrootricha in habitats of Central/Southern Maranhão. C. dichrootricha primarily used resources from the Cerrado, including soil to build their nests, pollen and floral oils; we concluded that gallery forest and Cerrado areas are intrinsically related to the maintenance of local populations of this species.

Habitat Use by Five Turtle Species in the Middle Mississippi River

Abstract Turtles face unique conservation challenges in modern modified river systems. Despite their ecological importance, gaps in knowledge still exist that may hinder their conservation. Turtle by-catch data from the US Army Corps of Engineers' Long-Term Resource Monitoring Program were analyzed for 5 turtle species (false map turtle, Graptemys pseudogeographica; red-eared slider, Trachemys scripta; common snapping turtle, Chelydra serpentina; smooth softshell turtle, Apalone mutica; and spiny softshell turtle, Apalone spinifera) to better understand macrohabitat and mesohabitat use. These species demonstrated differences in habitat use between various macrohabitats, substrata, velocity classes, and depth classes. Common snapping turtles and spiny softshell turtles were captured most often in tributaries, whereas red-eared sliders were captured most often in tributaries and closed side channels. Smooth softshell turtles used open side channels and unstructured main-channel borders most often. False map...