Macrohabitat Types Research Articles

Spatial distribution, host specificity, and affinity of Branchiura for surface and macrohabitat types in fish species from the Brazilian Amazon.

This study investigated the spatial distribution, parasite interactions, and affinities of Branchiura parasites according to macrohabitat and surface type on fish from the Araguari River, Amapá State, in the Brazilian Amazon. This study presents novel information on the interactions of branchiuran species with host fish, and how the morphology of their attachment structures is associated with different host surface morphologies, with and without scales. A total of 558 fish specimens of 26 species were collected, of which 109 fish (10 species) were parasitized by at least one branchiuran parasite; these were selected for further study. The parasites were collected from the buccal cavity, gills, fins, and integument of the host fish. Parasites with suction discs (Argulus) were mainly associated to hosts with small scales and no scales, while parasites with hooks (Dolops) were mainly associated to hosts with large scales. Overall, parasites with suction discs were more specialized per site than those with hooks.

Determinants of Aedes mosquito larval ecology in a heterogeneous urban environment- a longitudinal study in Bengaluru, India.

Aedes-borne disease risk is associated with contemporary urbanization practices where city developing structures function as a catalyst for creating mosquito breeding habitats. We lack better understanding on how the links between landscape ecology and urban geography contribute to the prevalence and abundance of mosquito and pathogen spread. An outdoor longitudinal study in Bengaluru (Karnataka, India) was conducted between February 2021 and June 2022 to examine the effects of macrohabitat types on the diversity and distribution of larval habitats, mosquito species composition, and body size to quantify the risk of dengue outbreak in the landscape context. A total of 8,717 container breeding sites were inspected, of these 1,316 were wet breeding habitats. A total of 1,619 mosquito larvae representing 16 species from six macrohabitats and nine microhabitats were collected. Aedes aegypti and Aedes albopictus were the dominant species and significantly higher in artificial habitats than in natural habitats. Breeding preference ratio for Aedes species was high in grinding stones and storage containers. The Aedes infestation indices were higher than the WHO threshold and showed significant linear increase from Barren habitat to High density areas. We found Ae. albopictus breeding in sympatry with Ae. aegypti had shorter wing length. A large proportion of larval habitats were man-made artificial containers. Landscape ecology drives mosquito diversity and abundance even at a small spatial scale which could be affecting the localized outbreaks. Our findings showed that sampling strategies for mosquito surveillance must include urban environments with non-residential locations and dengue transmission reduction programmes should focus on 'neighbourhood surveillance' as well to prevent and control the rising threat of Aedes-borne diseases.

Diet-habitat ecology of invasive tilapia and native fish in a tropical river catchment following a tilapia invasion

Many species of tilapia (a collection of fish species from the cichlidae family) have biological traits that make them successful invaders. Widespread herbivory has been observed across tilapia species, however knowledge on habitat preferences and tilapia interactions with native fish food webs is limited. This study was conducted three years after spotted (Pelmatolapia mariae) and Mozambique (Oreochromis mossambicus) tilapia were detected in the Mitchell River catchment, northern Australia. Tilapia diet and habitat preferences and their trophic position in native fish food webs was determined using a combination of stomach content, stable isotope, and habitat assessment analyses. Plant material was the most abundant item in tilapia stomachs, and some stomachs also contained other items in small quantities, such as fish eggs, small shrimp, and bivalves. Some niche overlap occurred between P. mariae and native omnivore or herbivore fish species. Macrohabitat type (in-channel (no tilapia), floodplain (no tilapia), weir (tilapia present)) was related to native fish food web structure, with weir food webs showing similarities to floodplain food webs. Floodplain habitats including creeks and wetlands were also most similar to weir habitats and may therefore be most at risk of colonization as tilapia spread throughout the catchment. This study clearly demonstrated that the successful rapid invasion of these two tilapia species is linked to suitable habitat with abundant food that fuels growth and reproduction. These findings increase understanding of diet related habitat use during new tilapia invasions and trophic interactions with native species.

Over 200,000 kilometers of free-flowing river habitat in Europe is altered due to impoundments

European rivers are disconnected by more than one million man-made barriers that physically limit aquatic species migration and contribute to modification of freshwater habitats. Here, a Conceptual Habitat Alteration Model for Ponding is developed to aid in evaluating the effects of impoundments on fish habitats. Fish communities present in rivers with low human impact and their broad environmental settings enable classification of European rivers into 15 macrohabitat types. These classifications, together with the estimated fish sensitivity to alteration of their habitat are used for assessing the impacts of six main barrier types (dams, weirs, sluices, culverts, fords, and ramps). Our results indicate that over 200,000 km or 10% of previously free-flowing river habitat has been altered due to impoundments. Although they appear less frequently, dams, weirs and sluices cause much more habitat alteration than the other types. Their impact is regionally diverse, which is a function of barrier height, type and density, as well as biogeographical location. This work allows us to foresee what potential environmental gain or loss can be expected with planned barrier management actions in rivers, and to prioritize management actions.

A cross-sectional study of Angiostrongylus malaysiensis in rats and gastropod hosts from recreational parks in Kuala Lumpur, Malaysia: Detection, risk factors and pathology.

Angiostrongylus malaysiensis is a potential zoonotic parasite, which reported to co-occur with A. cantonensis in human cerebrospinal fluid. It is a heteroxenous nematode that primarily develops through the early larval stages in gastropods and attains sexual maturity within rats. This study was conducted to determine the host species responsible for the reservoir of A. malaysiensis and investigate the risk factor for transmission among the hosts in Kuala Lumpur, Malaysia. Sampling was conducted in six recreational parks. The rats were trapped alive using steel wire traps with bait, while the gastropods were collected by active searching. The rats were euthanized and dissected to collect any adult worms observed. The molecular detection of A. malaysiensis was performed by PCR on gastropod tissue samples. Biotic and landscape factors were recorded for risk factor analysis. In total, 82 rats and 330 gastropods were collected throughout the study. Overall, 3.64% of gastropods and 32.9% of rats were infected with A. malaysiensis. Rattus tiomanicus (Malayan wood rat) and Parmarion martensi (Yellow-shelled semi-slug) were found as important hosts for A. malaysiensis. Host species, sampling site and macrohabitat type are risk factors associated with the prevalence of A. malaysiensis infection in rats. For gastropods, host species and sampling site are risk factors that correlate with the parasite detection. In total, 128 adult A. malaysiensis were recovered from the infected rats. The mean intensity of infection with adult A. malaysiensis was 4.65 for Rattus rattus complex and 4.90 for R. tiomanicus. Adult worms were found in the pulmonary artery or right ventricle, while eggs and first-stage larvae were found in capillaries of the caudal lung lobe. Infected lungs showed extravasated red blood cells in the alveolar spaces. The pulmonary arteries in the infected lung lobe were thickened. Kepong Metropolitan Park is the hotspot area for A. malaysiensis in Kuala Lumpur. These results provide essential information for public health officials to develop targeted interventions to reduce the transmission of A. malaysiensis in urban areas, particularly in recreational parks.

Freshwater Invertebrate Assemblage Composition and Water Quality Assessment of an Urban Coastal Watershed in the Context of Land-Use Land-Cover and Reach-Scale Physical Habitat

Stream ecosystems provide invaluable ecosystem services but are highly impacted ecosystems in need of water quality monitoring for habitat change impacts. Freshwater macroinvertebrate (FWI) assemblages have been shown to be good indicators of water quality and are known to be vulnerable to land-use land cover (LULC) and other habitat changes. The goal of this case study was to use an existing dominant LULC analysis in the Neponset River watershed, Massachusetts, USA, as LULC sampling treatment groups to deliberately capture the influence of these LULC effects on meso-scale habitat quality, FWI assemblages, and FWI water quality indices at eight sampling reaches. To achieve this goal, we collected physical habitat measurements and FWI samples in the summers of 2010 and 2012 at eight reach-scale stations spread across four previously determined LULC sub-watershed types (forest, residential, industrial, and golf) in the watershed. We expected that LULC change would influence the habitat quality, which would influence the FWI assemblage water quality scores and composition. We also expected that the water quality at these LULC sub-watershed types would be reflected in the FWI assemblage composition. We identified five major findings from our study. Our first finding was that the habitat quality in the Neponset River watershed was somewhat degraded relative to pristine conditions. Our second finding was that our habitat characterization analysis reflected some separation of our reach-scale macrohabitat types at land-use land-cover treatment stations with some correlations with microhabitat variables. Our third finding was that the water quality base on FWI assemblages was generally degraded in reference to pristine conditions. Our fourth finding was that, contrary to our expectations, there was no significant correlation between our reach-scale EPA habitat quality scores and FWI water quality scores. Our fifth finding was that our FWI assemblage NMS showed separation of land-use land-cover sampling stations and that that low pollution-tolerant taxa dominated some of our LULC sampling treatment stations and influenced NMS groupings.

Water Is Needed to Exist: Habitat Preferences of Tiger Beetles (Coleoptera: Cicindelidae) in a Desert Country.

Simple SummaryMany species of tiger beetles are habitat specialists, which make them useful as bioindicators of the status and changes in the quality of the environment. Their diversity and community structure in particular habitats can point to the stability of habitat. We studied six different macro and microhabitat factors that influence the habitat preferences of four Cicindelidae species occurring in different Tunisian desert areas. This is the one of only a few such studies in Africa. The results clearly show high habitat specialization of most studied taxa, as well as importance of water reservoirs in species distribution in the Sahara Desert.Tiger beetles are a group of predatory insects occurring mainly in diverse sandy areas, with particular species often characterised by narrow habitat preferences, which makes them both very important bioindicators for determining patterns of biodiversity and a flagship group for nature conservation. However, the precise roles of particular habitat parameters in the distribution of these beetles in desert areas are almost unknown. Habitat preferences for four tiger beetles species were analysed in Tunisia. Fifty samples from a major part of the country were collected, for which climate data, macrohabitat types. and soil parameters (soil humidity, salinity, pH, and structure) were studied. Here we show that most studied Cicindelidae were characterised by unique habitat preferences and did not co-occur with other ones, including two taxa found as habitat specialists, occurring in only one type of macrohabitat. Two other species were noted as more eurythopic and occupied 2–3 macrohabitat types, with Lophyra flexuosa as the most ubiquitous species not related to the measured parameters. The presence of a source of water (understood as a part of the habitat type, such as river banks and oases, or high soil humidity) was found as the most important factor in the distribution of the studied tiger beetle species. The present study is the first one focused on habitat preferences and habitat specialization of Cicindelidae fauna of Maghreb, and one of only a few in Africa.

Macrohabitat associations and phenology of carrion beetles (Coleoptera: Silphidae, Leiodidae: Cholevinae)

As decomposers of vertebrate carcasses, carrion beetles (Coleoptera: Silphidae, Leiodidae: Cholevinae) play a significant role in the functioning of terrestrial ecosystems. Despite this, the ecology and phenology of this group is relatively understudied. This research determines carrion beetle assemblages in three macrohabitats—native broadleaf woodland, non-native coniferous plantations and unforested sites of grassland or heathland. Further, it explores phenological changes over the growing season. Each macrohabitat type was replicated in eight geographical clusters, giving a total of 24 sites. Clusters were selected to give a wide geographical spread across Britain. Six pitfalls were set at each site, three baited with mice and three with cheese. Traps were set and collected fortnightly within every month from May to September 2016. The taxa differed in response to macrohabitat and growing season. Silphidae assemblages differed between forested and unforested habitats, whereas Leiodidae: Cholevinae were not distinguished by macrohabitat, although some specialists of forests were identified. Silphidae assemblages differed over the growing season, with May and June supporting a different suite of species to those in July—September. In contrast, Leiodidae: Cholevinae assemblages changed very little over the growing season though some species did prefer particular time periods. This research presents the first large-scale study of the macrohabitat preference and phenology of carrion beetles in Western Europe, providing important ecological and phenological information which could aid in their conservation.

BIRD COMMUNITY STRUCTURE IN MACROHABITATS OF THE AQUATICTERRESTRIAL TRANSITION ZONE IN THE PANTANAL WETLAND, BRAZIL

Ecological responses of bird communities in aquatic-terrestrial transition zones (ATTZs) are only partially understood. The aim of this study was to evaluate community structure of birds in different macrohabitats of ATTZs from a protected area in the Pantanal wetland, Brazil. The survey of birds was carried out in three types of macrohabitats: Erythrina fusca Lour. monospecific forest, shrubland and pioneer polyespecific forest, and flooded grassland. The bird community living within the ATTZ varied according to macrohabitat type and period of the wetland landscape. We emphasise the need to expand this protected area, and exert greater environmental control, since the region is not exempt from direct and indirect impacts derived from the Upper Paraguay River Basin.

From climate zone to microhabitat-environmental factors affecting the coastal distribution of tiger beetles (Coleoptera: Cicindelidae) in the south-eastern European biodiversity hotspot.

BackgroundTiger beetles (Coleoptera: Cicindelidae) are predatory insects usually occurring in various sandy habitats. In south-eastern Europe, especially in lowland areas located close to the sea coast, the diversity of Cicindelidae is one of the highest in the Palaearctic realm. Although previous studies conducted in different areas of the world show that many species are habitat specialists, unfortunately little is known about environmental factors affecting the diversity and distribution of tiger beetles in this region.Material and MethodsHabitat preferences for 12 tiger beetles taxa were analysed. Over 100 samples collected in eight countries located in coastal areas of the Black and Mediterranean Seas were studied, for which climate data, macrohabitat types, and soil parameters (soil humidity, salinity, pH, and structure) were investigated.ResultsMost studied Cicindelidae were characterised by narrow or very narrow habitat specialisation and did not co-occur with other ones, including 11 taxa found as habitat specialists occurring only in one or two types of macrohabitat. The most eurythopic species was Calomera littoralis nemoralis which occupied four macrohabitat types. The climatic zone, altitude, and humidity were found as the most important factors in the distribution of the studied tiger beetle species. Salt marshes and sandy sea beaches were noted as the most diverse macrohabitat types.DiscussionTiger beetle fauna of south-eastern Europe consists mainly of habitat specialists sensitive to environmental changes, which makes these beetles perfect bioindicators. Moreover, as a great number of studied Cicindelidae taxa occur in habitats which are under a significant human impact, we suggest that in the studied area the group can be successfully used as a flagship taxon for insect and nature conservation.

Parallel Behavioral Divergence with Macrohabitat inAnolis(Squamata: Dactyloidae) Lizards from the Dominican Republic

The ecomorph concept of the adaptive radiation of Caribbean anoles is characterized by a suite of behavioral, ecological, and morphological traits that are tightly linked to microhabitat use in lizards. However, most studies on the adaptive radiation of anoles have been conducted in a single macrohabitat type—lowland tropical forests. Because behavior can help organisms cope with different environmental conditions, we can predict that there will be key shifts in behavior within ecomorphs when examined across different macrohabitats, although this idea remains empirically underexplored. Here we utilized the replicated evolution of montane endemics from a primarily lowland species in a clade of trunk–ground Anolis lizards to test the hypothesis that shifts in basking behavior, wariness, and display behavior accompany divergence into montane habitats. The montane specialists A. armouri and A. shrevei each independently evolved from the primarily lowland dwelling A. cybotes in two widely separated mountain chains on the island of Hispaniola. We found evidence for a convergent behavioral response to the high-altitude macrohabitat: A. armouri and A. shrevei spend more time basking, utilize more open environments, and are warier than lowland A. cybotes. We also found divergence in display behavior in A. shrevei. We detected no evidence of divergence in locomotor behavior with elevation among active lizards. Together, our results suggest that the ecomorph concept would be enriched by extending observations of behavior (and other aspects of the phenotype) into different macrohabitats. Future work should focus on whether the observed behavioral shifts are clinal, reflecting local adaptation within A. cybotes, or fixed differences between the lowland generalist and montane species. Adaptation to the macrohabitat has previously been underappreciated as a source of behavioral diversity in Anolis lizards; this study is the first step toward documenting intraecomorph behavioral variation across divergent habitats.

Habitat selection and coexistence in small mammals of the southern Andean foothills (Argentina)

Habitat partitioning is considered one of the main mechanisms of coexistence among small mammals. This is especially evident in arid environments where resources are particularly scarce. Habitat characteristics such as vegetation heterogeneity and complexity are expected to increase species coexistence, increasing the number of microhabitats that can be occupied by species with different requirements. The Andean foothills can be considered as an ecotone between the Monte and Altoandina phytogeographic provinces as they harbor species from both. Consequently more species are thought to coexist in this area. The objectives of this study were to assess the macro- and microhabitat selection of the small mammal assemblage inhabiting the Andean foothills during wet and dry season and to determine how animals segregate environmental resources to ensure their coexistence. We found that habitat selection occurs at both scales in the Andean foothills. Two species, Eligmodontia moreni and Phyllotis xanthophygus, were capable of distinguishing among macrohabitat types, whereas all species showed habitat selection at the microhabitat scale. We registered selection during both seasons, with some overlap of resource selection during the wet season and the greatest segregation of microhabitat resources during the dry season. Therefore, this work evidence that the assembly of small mammals is sensitive to habitat structure especially in dry seasons where resources are constraints due to arid conditions of Andean foothills.

Roosting Preferences of North Island Brown Kiwis (Apteryx mantelli)

ABSTRACT The North Island Brown Kiwi (Apteryx mantelli) is a nocturnal endangered species endemic to New Zealand. The protection of suitable habitat is key to the species' recovery; however, little is known about their habitat requirements. We studied the diurnal roosting behaviours of kiwis by intensely tracking 41 radio-tagged, non-breeding adults from May 2010 to February 2012 on Ponui Island, New Zealand. From these birds, we collected 3,997 roosting locations in three different macro-habitat types (scrub, forest, and swamp) and described 223 roosting burrows in the forest macro-habitat. Overall, we discovered that kiwis were roosting generalists; three quarters of the study population was found in more than one macro-habitat and just 5% used only a single type of micro-habitat. However, using compositional analyses, we found that they did show some clear preferences. On a macro-habitat level, kiwis preferred forest habitat over scrub or swamp. Furthermore, on a micro-habitat level, they preferred roo...

Trophic pathways supporting juvenile Chinook and coho salmon in the glacial Susitna River, Alaska: patterns of freshwater, marine, and terrestrial food resource use across a seasonally dynamic habitat mosaic

Contributions of terrestrial-, freshwater-, and marine-derived prey resources to stream fishes vary over time and space, altering the energy pathways that regulate production. In this study, we determined large-scale use of these resources by juvenile Chinook and coho salmon (Oncorhynchus tshawytscha and Oncorhynchus kisutch, respectively) in the glacial Susitna River, Alaska. We resolved spatial and temporal trophic patterns among multiple macrohabitat types along a 97 km segment of the river corridor via stable isotope and stomach content analyses. Juvenile salmon were supported primarily by freshwater-derived resources and secondarily by marine and terrestrial sources. The relative contribution of marine-derived prey to rearing salmon was greatest in the fall within off-channel macrohabitats, whereas the contributions of terrestrial invertebrate prey were generally greatest during midsummer, across all macrohabitats. No longitudinal (upstream–downstream) diet pattern was discernable. These results highlight large-scale spatial and seasonal patterns of energy flow and the dynamic interplay of pulsed marine and terrestrial prey subsidies to juvenile Chinook and coho salmon in a large, complex, and relatively pristine glacial river.

Diet Partitioning in a Diverse Centrarchid Assemblage in the Atchafalaya River Basin, Louisiana

AbstractWe examined trophic and habitat resource partitioning among seven centrarchid species inhabiting four macrohabitat types in the Atchafalaya River basin (ARB), a 900‐km2 bottomland hardwood swamp in south‐central Louisiana. Fish (n = 2,036) were collected at 24 sites by boat electrofishing, and trophic position was determined from stomach contents and tissue analysis of 15N and 13C stable isotope signatures (n = 140). Stomach content analysis (index of relative importance), Morisita's index of dietary overlap, and canonical correspondence analysis revealed little effect of ARB macrohabitat type on centrarchid trophic relationships despite significant habitat alterations in dredged canals. Analyses revealed substantial diet overlap among three predominately insectivorous species (Bluegill Lepomis macrochirus, Redspotted Sunfish L. miniatus, and Longear Sunfish L. megalotis), whereas much more distinctive trophic positions were occupied by Largemouth Bass Micropterus salmoides (dominant prey = fish), Black Crappies Pomoxis nigromaculatus (palaemonid shrimp), Redear Sunfish L. microlophus (mollusks), and Warmouths L. gulosus (crayfish). Stable isotope signatures reflected dietary differences among species and complemented stomach content analyses in assessing the feeding ecology of these centrarchids, although isotopic similarities were sometimes higher than actual similarities in diet composition. Results suggest that centrarchid functional morphology and prey selection, combined with the diversity and productivity of ARB littoral habitats, effectively reduce the potential for competition among the seven cohabiting centrarchids.

Sampling Characteristics and Calibration of Snorkel Counts to Estimate Stream Fish Populations

AbstractSnorkeling is a versatile technique for estimating lotic fish population characteristics; however, few investigators have evaluated its accuracy at population or assemblage levels. We evaluated the accuracy of snorkeling using prepositioned areal electrofishing (PAE) for estimating fish populations in a medium‐sized Appalachian Mountain river during fall 2008 and summer 2009. Strip‐transect snorkel counts were calibrated with PAE counts in identical locations among macrohabitats, fish species or taxa, and seasons. Mean snorkeling efficiency (i.e., the proportion of individuals counted from the true population) among all taxa and seasons was 14.7% (SE, 2.5%), and the highest efficiencies were for River Chub Nocomis micropogon at 21.1% (SE, 5.9%), Central Stoneroller Campostoma anomalum at 20.3% (SE, 9.6%), and darters (Percidae) at 17.1% (SE, 3.7%), whereas efficiencies were lower for shiners (Notropis spp., Cyprinella spp., Luxilus spp.) at 8.2% (SE, 2.2%) and suckers (Catostomidae) at 6.6% (SE, 3.2%). Macrohabitat type, fish taxon, or sampling season did not significantly explain variance in snorkeling efficiency. Mean snorkeling detection probability (i.e., probability of detecting at least one individual of a taxon) among fish taxa and seasons was 58.4% (SE, 6.1%). We applied the efficiencies from our calibration study to adjust snorkel counts from an intensive snorkeling survey conducted in a nearby reach. Total fish density estimates from strip‐transect counts adjusted for snorkeling efficiency were 7,288 fish/ha (SE, 1,564) during summer and 15,805 fish/ha (SE, 4,947) during fall. Precision of fish density estimates is influenced by variation in snorkeling efficiency and sample size and may be increased with additional sampling effort. These results demonstrate the sampling properties and utility of snorkeling to characterize lotic fish assemblages with acceptable efficiency and detection probability, less effort, and no mortality, compared with traditional sampling methods.Received April 29, 2014; accepted July 23, 2014

Biogeography and conservation of aquatic fauna in spring-fed tropical canyons of the southern Sonoran Desert, Mexico

In arid regions, spring-fed habitats are frequently the only year-round source of surface water and are essential habitats for aquatic organisms and primary water sources for terrestrial animals and human settlements. While these habitats have been relatively well-studied in some regions, those of the southern Sonoran Desert have received little attention. In 2008 and 2009, we documented the biodiversity of aquatic animals at 19 sites across three arid mountain ranges in Sonora, Mexico, characterized macrohabitat types, examined seasonal variation in aquatic invertebrate communities, and explored the effects of an exotic fish (tilapia) on native communities. We documented >220 aquatic animal species, including several new species and range extensions for others. Macrohabitat type (oasis, tinaja, riffle, and seep) was more important than geographic location in structuring aquatic invertebrate communities at the scale of our study area (~9,000 km2). We found little evidence of predictable seasonal variation in invertebrate communities, despite dramatic hurricane-induced flooding. Aquatic vertebrates were not diverse across the study region (4 amphibian species and 2 species each of fishes and reptiles), but were often locally abundant. Presence of non-native tilapia at one site was associated with reduced abundances of native leopard frogs and reduced richness and density of native aquatic invertebrates. The most pressing aquatic habitat conservation concerns in the region, as in other deserts, are groundwater withdrawal, unmanaged recreational visitation, and the introduction of exotic species. Spring-fed habitats around the world have been called hotspots of freshwater biodiversity, and those of the Sonoran Desert are no exception.

Socio-ecology of the marsh rice rat (Oryzomys palustris) and the spatio-temporal distribution of Bayou virus in coastal Texas

Along the southeastern coast of the United States of America (USA), the marsh rice rat (Oryzomys palustris) is the primary host for the hantavirus, genotype Bayou. According to the socio-ecological model for a territorial, polygamous species, females should be distributed across space and time by habitat resources and predation risks, whereas males should space themselves according to the degree of female aggregation and reproductive synchrony. To investigate how females affect the male-male transmission paradigm of Bayou virus, rodents were captured, marked, released in two macrohabitat types and followed across a 30-month period. Microhabitat cover variables were quantified around the individual trap stations. A geodatabase was created from habitat and rodent capture data and analysed in a geographical information system. The ratio of breeding to non-breeding females was ~1:1, with breeding females overly dispersed and non-breeding females randomly dispersed. Spatial analyses revealed both macro- and microhabitat preferences in females. Compared to seronegatives, higher proportions of seropositive adult males were found consistently within closer proximities to breeding females but not to non-breeding females, indicating that male locations were not driven simply by habitat selection. Activities to acquire dispersed receptive females could be an important driver of Bayou virus transmission among male hosts. Herein, we describe an interdisciplinary effort providing a novel approach to elucidate the complexity of hantavirus trafficking and maintenance in rodent populations of a coastal marsh ecosystem.

Habitat use of redfin bullies (Gobiomorphus huttoni) in a small upland stream in Manawatu, New Zealand

This study uses Passive Integrated Transponder (PIT) technology to describe the habitat use patterns of the small, benthic redfin bully (Gobiomorphus huttoni). A 100-m reach of small upland stream in Manawatu, New Zealand was mapped to scale and inventoried for microhabitat variables. Flow velocity, depth, surface turbulence, substrate size and interstitial refuge space availability were measured in 0.25-m2 quadrats throughout the reach. A total of 67 redfin bullies were PIT tagged within the reach and monitored during day and night surveys in 2008 with a portable PIT monitoring system. Of these, 72 % were detected at least once and 64 % were detected 5 times or more within the study reach. Univariate analyses showed that redfin bullies utilized microhabitats that had larger substrate particles and more interstitial refuge spaces compared with all microhabitats available in the reach. During the day, redfin bullies were found in areas with larger substrates than areas where they were found at night. No differences in microhabitat use were found regarding gender, body size or season. Multivariate analysis revealed four macrohabitat types and showed that redfin bullies used deeper, complex macrohabitats during the day, then spread out to occupy all available macrohabitats at night. These findings have implications for river managers trying to cope with increasing anthropogenic impacts such as sedimentation.

Species richness and distribution of Neotropical rodents, with conservation implications

The correlates of species richness and conservation status of South American rodents were studied by analyzing the ranges of 791 species (belonging to 159 genera and 16 families). The distribution data (size of each species’ range in km 2 ) and the relative quantity of each macrohabitat type (in km 2 ) were obtained from the Global Mammal Assessment data bank of the International Union for Conservation of Nature (IUCN), and the Global Land Cover 2000, respectively. We excluded mainly island species from analyses but included those species that occur on both islands and the mainland. Habitats were grouped according to seven categories (shrubland, forest, grassland, savannah, wetlands, desert, and artificial). Mean range sizes varied significantly among families, with members of the family Cuniculidae having larger ranges than the species belonging to the rest of the families. Mean range size did not differ significantly between endemic and non-endemic taxa. There was a significant positive relation between total species richness and the availability of habitat types. Specialized species (i.e., those linked to a single habitat type) were found especially in forests, but shrublands and grasslands were also important. IUCN threatened species were distributed in a scattered way, and essentially in forests, grasslands, and shrublands. No region of the Neotropics housed more than two to three threatened taxa, apart from a spot in north-central Peru with five species. The richness of IUCN threatened species was higher in the montane forest ecosystems of the Andes, north-central Peru, than in other areas of South America. There was a mismatch between the hotspot maps for threatened and endemic species. The conservation implications of these patterns are discussed.