Refuge utilization and preferences between competing intertidal crab species

Many invertebrates avoid predation risk by seeking and defending refuges that can be in limited supply, producing strong intra- and inter-specific interference competition. Previous experimental studies in central Chile demonstrated that interference competition for refuges is the primary factor driving habitat segregation between the predatory crabs Acanthocyclus gayi and A. hassleri, with the latter species monopolizing galleries inside mussel beds in the mid intertidal zone and limiting A. gayi to rock crevices. Yet, habitat partitioning between rival species can result from differences in habitat preferences and not solely from interference interactions. Moreover, since A. gayi is also known to shelter in turf-forming algae (predominantly Gelidium), which dominates extensive areas in the low intertidal zone, among-sites variation in the turf morphology and abundance could modify habitat preferences and the pattern of inter-specific interactions. We experimentally evaluated refuge habitat preferences of individual, similarly-sized adult A. gayi and A. hassleri in the laboratory, comparing choice patterns across multiple trials with paired combinations of the main refuge types commonly used by crabs in the field: a) mussel galleries, b) rock crevices, c) short algal turf, and d) tall algal turf. Our results showed that both species display a strong ranking of preferences for some refuge habitats over others. In general, mussel galleries were the preferred refuge type for both crab species, but their preference rankings changed depending on turf morphology. When turf was short, A. hassleri and A. gayi made identical refuge choices, strongly preferring mussel galleries over crevices and these over the short turf. In contrast, when the turf was tall A. gayi selected equally the tall turf or mussel galleries, and these were strongly preferred over crevices. A. hassleri, on the other hand, largely ignored tall turf and kept the highest preference for mussel galleries. A field experiment in which crabs were offered to foraging birds demonstrated that A. hassleri is more susceptible than A. gayi to predation by kelp gulls when outside refuges. Differences in patterns of coloration between crabs may underlie between-species differences in predation susceptibility and their habitat choices. These results suggest that the among-site differences in turf morphology (height and shape of fronds), which is largely driven by varying intensity of upwelling, could affect crab preferences for refuge habitats and the relative importance of inter-specific interference competition.     

Universal Optimization of Flight Initiation Distance and Habitat-Driven Variation in Escape Tactics in a Namibian Lizard Assemblage

Some aspects of escape predicted by theoretical models are intended to apply universally. For example, flight initiation distance (distance between an approaching predator and prey when escape begins) is predicted from predation risk and the costs of escaping. Escape tactics and refuge selection are not currently predicted by theoretical models, but are expected to vary with structural features of the habitat. One way of studying such variation is to compare aspects of antipredatory behavior among sympatric species that differ in habitat or microhabitat use. In an assemblage of lizards in northwestern Namibia, we conducted experiments to test predictions of escape theory for three risk factors in representatives of three families and observed escape tactics in additional species. As predicted by escape theory, flight initiation distance increased with directness of a predator's approach and predator speed in Agama planiceps, Mabuya acutilabris, and Rhotropus boultoni, and with distance from refuge in M. acutilabris. As predicted by theory, the probability of entering refuge increased with risk in R. boultoni. All available data indicate that flight initiation distance and refuge entry by lizards conform to theoretical predictions. Escape tactics varied greatly as a function of habitat type: (1) arboreal species fled up and around trees and sometimes entered tree holes; (2) saxicolous species used rock crevices as refuges, but differed in tactics prior to entering refuges; and (3) terrestrial species fled into bushes or other vegetation, often to the far sides of them. Some M. acutilabris entered small animal burrows or buried themselves in sand beneath bushes. Escape tactics varied even among congeners in Mabuya, highlighting the important effect of habitat structure on them. Although habitat partitioning has traditionally been viewed as favoring species coexistence, an interesting by‐product appears to be structuring of escape tactics in lizard communities.     

Bayesian inference of species diffusion in the West African Agama agama species group (Reptilia,Agamidae)

The savannah and tropical forest biomes of Africa have a long history of expansion and contraction, and the recent and rapid spread of dry savannah habitats has influenced the spatial and temporal diversification of vertebrate taxa across this region. We used a combination of species tree and phylogeographic methods to describe the spatio-temporal changes through time and across space (= species diffusion) in a clade of seven West African lizard species in the Agama agama species group. A Bayesian species tree diffusion approach was used to compare the relative rates at which species ranges changed across the landscape. We found that some species have high diffusion rates characterized by significant movement in their range location and minor changes to their overall range size, whereas other species show little movement in their range centre with an exponential increase in range size. This discrepancy between the rates that range locations shift versus change in their relative area could be linked to populations tracking their preferred habitats through time. A continuous Bayesian phylogeography approach using a relaxed random walk model was used to estimate the timing and rate of population size change and geographic diffusion in A. picticauda, the single species in the group with an extensive African distribution from Mauritania to Ethiopia. The mean dispersal rate of A. picticauda increased dramatically throughout the Pleistocene, and a Bayesian skyride analysis supports exponential population growth over this same time period. A comparison of genetic diversity across different loci and species suggests that A. lebretoni experienced a mitochondrial selective sweep that has caused a deficit of variation at this locus in relation to nuclear loci.     

Consistency in the habitat degree of invasion for three invasive plant species across Mediterranean islands

Habitats are known to vary in their vulnerability to invasion by alien plants and different species often colonise distinct habitats. To assess the consistency in the degree of invasion of particular habitats, this study examined the frequency of occurrence and local abundance of three invasive plant taxa: Ailanthus altissima, Carpobrotus spp., and Oxalis pes-caprae across different habitat types on four representative Mediterranean islands. We conducted systematic field surveys recording the presence-absence and cover of these taxa on the islands of Mallorca, Corsica, Sardinia and Crete. Drawing on the results of 5,285 sample points, the frequency of occurrence of the three invaders tends to be higher than expected in urban, ruderal and roadside habitats. In contrast, scrub habitats rarely contain any of the three invaders, indicating that they may be more resistant to invasion. The degree of invasion, determined by the local abundance of an invasive plant in any one habitat, varies according to the identity of the invader and the island. However, based on average abundance, Oxalis pes-caprae exhibits the highest degree of invasion, and Carpobrotus spp. the least. There is no indication that any one of the four islands is more prone to either higher frequencies or abundances of the three invaders. These patterns suggest that anthropogenic changes in Mediterranean islands will increase the vulnerability of certain habitats to invasion and increase the distribution of these three invasive taxa at any of the four islands.     

Divergent habitat use of two urban lizard species

Faunal responses to anthropogenic habitat modification represent an important aspect of global change. In Puerto Rico, two species of arboreal lizard, Anolis cristatellus and A. stratulus, are commonly encountered in urban areas, yet seem to use the urban habitat in different ways. In this study, we quantified differences in habitat use between these two species in an urban setting. For each species, we measured habitat use and preference, and the niche space of each taxon, with respect to manmade features of the urban environment. To measure niche space of these species in an urban environment, we collected data from a total of six urban sites across four different municipalities on the island of Puerto Rico. We quantified relative abundance of both species, their habitat use, and the available habitat in the environment to measure both microhabitat preference in an urban setting, as well as niche partitioning between the two different lizards. Overall, we found that the two species utilize different portions of the urban habitat. Anolis stratulus tends to use more “natural” portions of the urban environment (i.e., trees and other cultivated vegetation), whereas A. cristatellus more frequently uses anthropogenic structures. We also found that aspects of habitat discrimination in urban areas mirror a pattern measured in prior studies for forested sites in which A. stratulus was found to perch higher than A. cristatellus and preferred lower temperatures and greater canopy cover. In our study, we found that the multivariate niche space occupied by A. stratulus did not differ from the available niche space in natural portions of the urban environment and in turn represented a subset of the niche space occupied by A. cristatellus. The unique niche space occupied by A. cristatellus corresponds to manmade aspects of the urban environment generally not utilized by A. stratulus. Our results demonstrate that some species are merely tolerant of urbanization while others utilize urban habitats in novel ways. This finding has implications for long‐term persistence in urban habitats and suggests that loss of natural habitat elements may lead to nonrandom species extirpations as urbanization intensifies.     

Spatial and Temporal Distribution of Northern Waterthrushes Among Nonbreeding Habitats in Southwestern Puerto Rico1

We surveyed nonbreeding Northern Waterthrushes (Seiurus noveboracensis) in several coastal habitats in southwestern Puerto Rico, West Indies. Waterthrush abundance was highest (mean = 2.2/point) in well‐developed mangrove habitats characterized by large trees and standing water, and lowest (mean = 0.1/point) in dry coastal scrub and savannah. Within the latter habitats, waterthrushes were more common in moist microhabitats such as temporary ponds and dry washes. Abundance in most habitats declined between October and January, probably a result of the presence of transients during the October surveys, Between January and March, abundance in mature red mangrove (Rhizophora mangle) forests increased dramatically, suggesting that this habitat provides a refuge for birds at the end of the dry season and prior to northward migration. In conjunction with other data demonstrating the use of coastal red mangroves as nocturnal roosting sites, these results suggest that mangroves are the most important nonbreeding habitat for this species. Conservation of this globally threatened habitat may thus be important for the long‐term stability of waterthrush populations.     

Invasive birds in a novel landscape: habitat associations and effects on established species

Studying the relationships among introduced species, their preferred habitats, and native species can be important for predicting the effects of invasions on native populations. Examining the colonization of North America by the Eurasian collared‐dove Streptopelia decaocto, we quantified the habitat characteristics of sites most likely to be occupied by this invasive bird species in the early stages of the invasion. Further, we studied the relationship between collared‐dove abundance and the abundance of other dove species in the study area, anticipating a negative effect on established species following the introduction of a potential competitor. Linking satellite‐derived landcover data with winter bird community data gathered from 444 study sites in Florida, USA from 1999 to 2008, we found that collared‐doves were more likely to occur in landscapes that had been highly‐modified by human activity than in forested landscapes. Collared‐dove abundance increased as the proportion of the landscape characterized as low‐intensity development and medium/high‐intensity development increased. The probability of collared‐doves occurring at a site was also related to the spatial proximity of other sites reporting doves (positive spatial autocorrelation). Contrary to our expectations, the site‐level abundance of four other dove species all increased with collared‐dove abundance throughout the sampling period. Interactions between collared‐doves and native species should be further studied in different environments as this invasive bird rapidly colonizes North America.     

Assessing the importance of disturbance, site conditions, and the biotic barrier for dandelion invasion in an Alpine habitat

Several factors have been identified as relevant in determining the abundance of non-native invasive species. Nevertheless, the relative importance of these factors will vary depending on the invaded habitat and the characteristics of the invasive species. Due to their harsh environmental conditions and remoteness, high-alpine habitats are often considered to be at low risk of plant invasion. However, an increasing number of reports have shown the presence and spread of non-native plant species in alpine habitats; thus, it is important to study which factors control the invasion process in these harsh habitats. In this study, we assessed the role of disturbance, soil characteristics, biotic resistance and seed rain in the establishment and abundance of the non-native invasive species Taraxacum officinale (dandelion) in the Andes of central Chile. By focusing on human-disturbed patches, naturally disturbed patches, and undisturbed patches, we did not find that disturbance per se, or its origin, affected the establishment and abundance of T. officinale. The abundance of this non-native invasive species was not negatively related to the diversity of native species at local scales, indicating no biotic resistance to invasion; instead, some positive relationships were found. Our results indicate that propagule pressure (assessed by the seed rain) and the abiotic soil characteristics are the main factors related to the abundance of this non-native invasive species. Hence, in contrast to what has been found for more benign habitats, disturbance and biotic resistance have little influence on the invasibility of T. officinale in this high-alpine habitat.     

Environmental and vegetation variables have a greater influence than habitat fragmentation in structuring lizard communities in remnant urban bushland

Abstract The expansion of urban areas and adjacent farming land into natural landscapes modifies habitats and produces small isolated pockets of native vegetation. This fragmentation of the natural habitat subdivides animal communities, reduces population sizes and increases vulnerability to extinction. In this paper we investigate whether fragmentation decreases lizard species richness, composition, overall abundance and abundance at the species level. Urban remnants consisting of five small (< 10 ha) and four large (> 10 ha) fragments of natural bushland were paired with continuous bushland areas located near Hobart, Tasmania, Australia. These remnants were surveyed six times, using pitfall traps, from November 2001 to March 2002. Lizard species richness and abundance were not significantly influenced by habitat fragmentation or fragment size. Egernia whitii was the only lizard species significantly influenced by fragment size, and was only present in large fragments and continuous bush. Vegetation type and structure as well as environmental variables (geology and aspect) influenced the structure of reptile communities. Lizard species that were able to use a number of different habitat types were found to persist at most sites, irrespective of fragment size. Edge environment did not significantly influence lizard species richness or abundance in remnant areas. Lizard species richness was significantly lower in sites that had a high ratio of exotic to native plant species. Therefore, if remnants continue to be invaded by exotic plants, lizard species that require native plant communities will become increasingly vulnerable to local extinction. Our results suggest that lizard species requiring specialized habitats, such as E. whitii, may persist in large urban remnants rather than small urban remnants because large reserves are more likely to encompass rare habitats, such as rocky outcrops. Habitat heterogeneity, rather than size, may be the key to their persistence.     

Disturbance regime and limits on benefits of refuge use for fishes in a fluctuating hydroscape

Refuge habitats increase survival rate and recovery time of populations experiencing environmental disturbance, but limits on the ability of refuges to buffer communities are poorly understood. We hypothesized that importance of refuges in preventing population declines and alteration in community structure has a non‐linear relationship with severity of disturbance. In the Florida Everglades, alligator ponds are used as refuge habitat by fishes during seasonal drying of marsh habitats. Using an 11‐year record of hydrological conditions and fish abundance in 10 marshes and 34 alligator ponds from two regions of the Everglades, we sought to characterize patterns of refuge use and temporal dynamics of fish abundance and community structure across changing intensity, duration, and frequency of drought disturbance. Abundance in alligator ponds was positively related to refuge size, distance from alternative refugia (e.g. canals), and abundance in surrounding marsh prior to hydrologic disturbance. Variables negatively related to abundance in alligator ponds included water level in surrounding marsh and abundance of disturbance‐tolerant species. Refuge community structure did not differ between regions because the same subset of species in both regions used alligator ponds during droughts. When time between disturbances was short, fish abundance declined in marshes, and in the region with the most spatially extensive pattern of disturbance, community structure was altered in both marshes and alligator ponds because of an increased proportion of species more resistant to disturbance. These changes in community structure were associated with increases in both duration and frequency of hydrologic disturbance. Use of refuge habitat had a modal relationship with severity of disturbance regime. Spatial patterns of response suggest that decline in refuge use was because of decreased effectiveness of refuge habitat in reducing mortality and providing sufficient time for recovery for fish communities experiencing reduced time between disturbance events.     

Sleeping site selection of Francois’s langur (<Emphasis Type="Italic">Trachypithecus francoisi</Emphasis>) in two habitats in Mayanghe National Nature Reserve,Guizhou, China

Sleeping site selection is an important aspect of the behavioral biology of primates. Comparison of different habitats for the same species in this context enhances understanding of their adaptation to altered environments. We collected data on sleep-related behaviors for 6 groups of Francois’s langur (Trachypithecus francoisi) in two habitats, in Mayanghe National Nature Reserve, Guizhou, China. Regardless of habitat, all sleeping sites were located in areas of steep terrain of ≥60°. In undisturbed habitat, sleeping sites were located only in evergreen broadleaf forest with rock caves and crevices surrounded mainly by a vegetation layer of shrub + rock. In disturbed habitat, sleeping sites were also located in mixed evergreen and deciduous broadleaf forest and in grassland, including rock caves, crevices, and pits, surrounded mainly by arbor + shrub and shrub + rock. Wild food availability was higher in undisturbed habitat than disturbed habitat, but food abundance around sleeping sites was lower. Water sources included river and seasonal gully or pond. There was strong positive correlation between use of sleeping sites away from the river valley and occurrence of seasonal water sources. The number of sleeping sites varied across groups, numbering 6, 7, and 10 for three specific groups. Few sleeping sites were used all year round. Six consecutive nights was the longest recorded run. Francois’s langurs’ sleeping habits differed between two habitats. In undisturbed habitat, minimizing predation risk appeared to predominate, expressed by choosing steep terrain, open visual field, and inconspicuous presleeping behavior. In disturbed habitat, along with predation avoidance, food resources may strongly influence sleeping site selection, as demonstrated by the richer food abundance and greater foraging activity around the site. Finally, water resources may influence choice of sites distant from the river; such sites were used less frequently during water shortages.     

Habitat structure modified by an invasive grass enhances inundation withstanding in a salt-marsh wolf spider

Vegetation and underground structures are known to influence flood avoidance and flood resistance in invertebrates. In bimonthly-flooded European salt marshes, recent invasions by the nitrophilous grass Elymus athericus strongly modified usual habitat structure, notably by the production of a deep litter layer. Consequently, invaded habitats provide more interstitial spaces that may act as a refuge during flood events. By using both controlled and field designs, we tested whether invaded habitats may change the ability to resist flooding by the creation of new refuges during tides for a ground-living, predatory arthropod. The wolf spider Arctosa fulvolineata was employed as a model species since it occurs abundantly in both invaded and uninvaded salt-marsh habitats. In the field, its abundance strongly decreased (divided by three) after tidal flooding in uninvaded habitats by but did not change in invaded patches. Under controlled laboratory conditions, ten times more individuals withstood simulated flooding in the presence of litter and less decided to float. The presence of litter did not influence flood resistance, i.e. survival underwater. Our results show that habitat structure (i.e. the presence of litter) influences flood-avoiding behavior of A. fulvolineata, by providing more refuges. As the invasion of E. athericus alters salt-marsh habitat structure, it may enhance population size of a rare predatory spider by changing its behavior during flooding and resulting in less deleterious impacts of tides. Yet biological invasions are detrimental for biodiversity conservation, our study shows that an invasive species might indirectly benefit a few mobile rare species in a flood-disturbed habitat.     

Secondary invasion of <Emphasis Type="Italic">Acer negundo</Emphasis>: the role of phenotypic responses versus local adaptation

During plant species invasions, the role of adaptive processes is particularly of interest in later stages of range expansion when populations start invading habitats that initially have not been disposed to invasions. The dioecious tree Acer negundo, primarily invasive in Europe in wet habitats along riversides and in floodplains, has increased its abundance in dry habitats of industrial wasteland and ruderal sites during the last decades in Eastern Germany. We chose 21 invasive populations from wet and from dry habitats in the region of Halle, Saxony-Anhalt, Germany, to test whether Acer negundo exhibits a shift in life-history strategy during expansion into more stressful habitats. We analyzed variables of habitat quality (pH, soil moisture, exchangeable cations, total C and N content) and determined density, sex ratio and regeneration of the populations. In addition, we conducted germination experiments and greenhouse studies with seedlings in four different soil moisture environments. Local adaptation was studied in a reciprocal transplant experiment. We found habitat type differentiation with lower nutrient and water supply at the dry sites than at the moist sites and significant differences in the number of seedlings in the field. In accordance, seeds from moist habitats responded significantly faster to germination treatments. In the transplant experiment, leaf life span was significantly larger for populations originating from dry habitat types than from moist habitats. This observed shift in life history strategy during secondary invasion of A. negundo from traits of establishment and rapid growth towards traits connected with persistence might be counteracted by high gene flow among populations of the different habitat types. However, prolonged leaf life span at dry sites contributed remarkably to the invasion of less favourable habitats, and, thus, is a first indication of ongoing adaptation.     

Natal Den Selection by Florida Panthers

ABSTRACT Information regarding habitat types selected by federally endangered Florida panthers (Puma concolor coryi) at natal den sites is needed because habitats used for parturition and kitten rearing potentially influence fitness of individuals and viability of the population. We located 51 natal den sites of 30 female panthers and performed a Euclidean distance analysis to determine which habitat types were selected and avoided at dens in south Florida, USA. Panther dens were closer to upland hardwoods, pinelands, and mixed wet forests (P ≤ 0.003) and farther from freshwater marsh-wet prairie (P = 0.009). We recommend that habitat protection efforts prioritize blocks of land that have abundant patches of upland hardwood, pinelands, and mixed wet forests to maintain preferred panther denning habitat.     

Butterfly community ecology: the influences of habitat type,weather patterns,and dominant species in a temperate ecosystem

We compared variation in butterfly communities across 3 years at six different habitats in a temperate ecosystem near Boulder, Colorado, USA. These habitats were classified by the local Open Space consortium as Grasslands, Tallgrass, Foothills Grasslands, Foothills Riparian, Plains Riparian, and Montane Woodland. Rainfall and temperature varied considerably during these years. We surveyed butterflies using the Pollard‐Yates method of invertebrate sampling and compared abundance, species richness, and diversity across habitats and years. Communities were most influenced by habitat, with all three quantitative measures varying significantly across habitats but only two measures showing variation across years. Among habitats, butterfly abundance was higher in Plains Riparian sites than in Montane Woodland or Grassland sites, though diversity was lowest in Plains Riparian areas. Butterfly species richness was higher in Foothills Riparian sites than it was in all but one other habitat (Tallgrass). Among years, butterfly abundance and species richness were lower during the year of least rainfall and highest temperatures, suggesting a substantial impact of the hot, dry conditions. Across habitats and years, butterfly abundance was consistently high at Plains Riparian and Foothills Riparian sites, and richness and diversity were consistently high in Foothills Riparian areas. These two habitats may be highly suitable for butterflies in this ecosystem, regardless of weather conditions. Generally low abundance and species richness in Montane Woodlands sites, particularly in 2002, suggested low suitability of the habitat to butterflies in this ecosystem, and this may be especially important during drought‐like conditions. Finally, to examine the effect that the presence of the very abundant non‐native species Pieris rapae L. (Lepidoptera: Pieridae) has on these communities, we re‐analyzed the data in the absence of this species. Excluding P. rapae dramatically reduced variation of both butterfly abundance and diversity across habitats, highlighting the importance of considering community membership in analyses like ours.     

Taxon specific response of carabids (Coleoptera,Carabidae) and other soil invertebrate taxa on invasive plant Amorpha fruticosa in wetlands

False indigo (Amorpha fruticosa L.) is an invasive exotic plant introduced to Europe in the early eighteenth century. Its spread has been rapid, particularly in disturbed wetland habitats, where it forms dense impermeable monospecific stands and modifies habitat conditions. The impact of A. fruticosa on native plant communities has been well analyzed, however knowledge concerning the possible effects on soil invertebrates and particularly carabid beetles is completely lacking. This study analyzed the impact of an A. fruticosa invasion on carabid beetles and other soil invertebrates. Soil fauna was sampled by pitfall traps at natural habitats, initially colonized by A. fruticosa, and habitats largely invaded by A. fruticosa. In total 2,613 carabid beetles belonging to 50 species and 72,166 soil invertebrates were collected. The invasion of A. fruticosa strongly affected the carabid beetle species composition, which clearly differed between all studied sites. Widespread euritopic carabid beetle species showed positive responses to A. fruticosa invasion, while the activity density of open habitat species strongly declined. Mean individual biomass was significantly higher at invaded sites due to increased incidence of large carabids (genus Carabus Linné, 1758). Carabid beetle activity density and abundance of soil invertebrates were considerably higher at invaded sites than in natural sites. Conversely, the impact of A. fruticosa on carabid beetle species richness and diversity was less pronounced, most likely due to immigration from adjacent habitats. Changes in carabid beetle species composition and abundance of soil invertebrates were most likely due to changes in vegetation structure and microclimate. The results suggest that A. fruticosa invasion considerably affected carabid beetles, an insect group that is only indirectly related to plant composition. Therefore, severe future changes can be expected in invertebrate groups that are closely related to plant composition, since A. fruticosa cannot be completely removed from the habitat and covers relatively large areas.     

Bird species of conservation concern along urban gradients in Italy

The worldwide increase of urbanization requires better knowledge of its effects on biodiversity. We investigated the distribution of 41 breeding bird species of conservation concern along an urban gradient (centre, inner periphery, outer periphery, sparsely built up area) in Italian towns. We used data on the presence of bird species of conservation concern in each square of the grid of 27 urban atlases to obtain the frequency of each species in each sector. The frequency of species of conservation concern—for both passerines and non passerines—decreased in more urbanised sectors. An increased degree of urbanization is particularly unfavourable to the following groups of species of conservation concern: raptors (except Falco tinnunculus); galliforms; granivorous, ground-nesting passerines; and passerines of bush-shrub habitats. Our findings did not change substantially if we limited our analysis to small, intermediate or large towns. Our results confirm that urban areas are avoided by the majority of specialists and rare species. However, the frequency of aerial feeders and Jynx torquilla, Phoenicurus phoenicurus, Monticola solitarius and Muscicapa striata did not decrease in more urbanised sectors. Since these species include some whose main habitats are dwindling, urban areas might be a refuge for them. Conservation efforts in towns should preserve the conditions (presence of mature trees, habitat heterogeneity, availability of insects, suitable nesting sites in buildings) favouring these species.     

Restored oyster reefs and living shorelines can augment predator trophic dynamics

Coastal habitat loss has led to declines in many higher trophic level predators. These declines can be mitigated through habitat restoration, which putatively enhances predator populations and trophic dynamics by creating foraging opportunities in reestablished habitat, but this lacks empirical support. Here, we assess the prediction restored coastal habitat supports sportfish feeding relationships similar to natural habitat, at restored oyster reefs (Crassostrea virginica) and living shoreline habitats in Florida, U.S.A. Stable isotopes and gut contents were analyzed from young sportfish (i.e. predatory fish targeted by anglers) collected at control and restored sites for up to 3 years. The influence of habitat features, predator size, and prey availability on carbon and nitrogen isotope values were examined using a model species (mangrove/gray snapper [Lutjanus griseus]). In summary, sportfish species had distinct isotopic values, consuming similar prey but in different proportions between habitats. Prey abundance and richness, and reef height were influential predictors of L. griseus stable isotope values, with restored reefs contributing to their diet more than controls according to Bayesian mixing models. The trophic niche area of L. griseus and their predominant prey achieved trophic equivalence between restored and natural oyster reefs within 1 year following restoration. Stabilized living shorelines attained trophic equivalency to natural shorelines, but may take longer to accrue prey for some species. These findings generate fundamental ecological knowledge and actionable science, including targets, timelines, and indicator species, that natural resource managers and restoration practitioners can use to assess trophic structure and success of coastal habitat restoration.     

Multi-scale habitat selection and foraging ecology of the eurasian hoopoe (<Emphasis Type="Italic">Upupa epops</Emphasis>) in pine plantations

Bird conservation can be challenging in landscapes with high habitat turnover such as planted forests, especially for species that require large home ranges and juxtaposition of different habitats to complete their life cycle. The eurasian hoopoe (Upupa epops) has declined severely in western Europe but is still abundant in south-western France. We studied habitat selection of hoopoes in pine plantation forests using a multi-scale survey, including point-counts at the landscape level and radio-tracking at the home-range scale. We quantified habitat use by systematically observing bird behaviour and characterized foraging sites according to micro-habitat variables and abundance of the main prey in the study area, the pine processionary moth (Thaumetopoea pityocampa). At the landscape scale, hoopoes selected habitat mosaics of high diversity, including deciduous woods and hedgerows as main nesting sites. At the home-range scale, hoopoes showed strong selection for short grassland vegetation along sand tracks as main foraging habitats. Vegetation was significantly shorter and sparser at foraging sites than random, and foraging intensity appeared to be significantly correlated with moth winter nest abundance. Hoopoe nesting success decreased during the three study years in line with processionary moth abundance. Thus, we suggest that hoopoes need complementation between foraging and breeding habitats to establish successfully in pine plantations. Hoopoe conservation requires the maintenance of adjacent breeding (deciduous woods) and foraging habitats (short swards adjacent to plantation edges), and consequently depends on the maintenance of habitat diversity at the landscape scale.     

Predation risk predicts use of a novel habitat

Predator–prey interactions are often highly co‐evolved, with selection over time for prey with morphological and behavioral traits that minimize predation risk. Consequently, in many environments prey choose among potential habitats according to their refuge value. It is unclear, however, when presented with new habitats, if prey are able to evaluate the predation risk of these relative to familiar habitats and utilize these in accordance with their value. We tested whether, along the east coast of the USA, native mud crabs Panopeus herbstii utilize the non‐native alga Gracilaria vermiculophylla according to its relative refuge value. Experiments examining predation by blue crabs Callinectes sapidus on mud crabs revealed that the non‐native alga had an intermediate refuge value relative to native oysters, which were the most protective, and unvegetated sediment, which was the least. In subsequent choice experiments, mud crabs selected oysters over alga over unvegetated sediment, in accordance with habitat refuge values. Further, in field experiments, the use of Gracilaria by mud crabs was inversely related to the proximity of the alga to the preferred habitat type, oysters, and was reduced by the presence of a blue crab predator. Consequently, mud crabs are utilizing the non‐native alga Gracilaria in accordance with its intermediate refuge value. The relative refuge value of non‐native vs native habitat‐forming species may provide a baseline expectation against which to measure the speed of learning and opportunism in the response of native prey to novel protective habitats.