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41 result(s) for "macrohabitat"
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Habitat Selection as the Mechanism for Thermoregulation in a Northern Population of Massasauga Rattlesnakes (Sistrurus catenatus)
Although temperature is recognized as an important barrier to reptile distribution, the mechanisms of this limitation are poorly understood. We investigated the association between temperature, habitat selection, and thermoregulation in a population of massasauga rattlesnakes (Sistrurus catenatus) near their northern range limit, where low temperatures are likely an important constraint. Movement data indicated that the lower limit of the massasauga's performance range (i.e., ≥ 50% of optimal) was 19.9 °C. Operative environmental temperatures were almost always below the massasauga's preferred range (30.0–33.6 °C) and frequently below its performance range in spring and fall. Massasaugas differed from other northern snakes by thermoregulating primarily by microhabitat selection and not by macrohabitat selection. Massasaugas thermoregulated more effectively as their visibility increased and forest cover decreased. Gravid females increased thermoregulatory behaviour in response to low temperatures in spring and summer. Male and nongravid female massasaugas did not take full advantage of thermoregulatory opportunities in the spring and fall, and as a consequence were often too cool to perform essential functions such as prey capture. Our results are consistent with the hypothesis that temperature limits massasauga distribution primarily via effects on gestation and hence juvenile recruitment.
A Classification System for Colombian Wetlands: an Essential Step Forward in Open Environmental Policy-Making
Knowledge about the distribution and diversity of wetlands has become an essential tool for environmental management and policy-making. Yet, while recent estimates indicate that 27% of the area of Colombia is covered by wetlands and despite a number of regional studies, information about the diversity of wetlands nationally is scarce. In response, we present a national wetland classification system that is based on an ecological approach, from the perspective of wetland scientists, and which builds upon the assumptions underlying the flood pulse concept and hydrogeomorphic approach. Thus, the approach and structure of the Brazilian wetland classification system are used, with geomorphological adjustments made according to Colombia’s topography. The classification is hierarchical, multi-scale, functional, and organized according to four levels (system, macroregion, subsystem, and class), with the wetland diversity of Colombia represented nationally by 89 macrohabitats across marine-coastal, inland, and anthropogenic systems. The primary purpose of this classification is to provide integrated and organized information on the distribution and diversity of Colombian wetlands that will serve as a baseline for transparent environmental policy-making.
Exquisitely Preserved Fossil Snakes of Messel: Insight into the Evolution, Biogeography, Habitat Preferences and Sensory Ecology of Early Boas
Our knowledge of early evolution of snakes is improving, but all that we can infer about the evolution of modern clades of snakes such as boas (Booidea) is still based on isolated bones. Here, we resolve the phylogenetic relationships of Eoconstrictor fischeri comb. nov. and other booids from the early-middle Eocene of Messel (Germany), the best-known fossil snake assemblage yet discovered. Our combined analyses demonstrate an affinity of Eoconstrictor with Neotropical boas, thus entailing a South America-to-Europe dispersal event. Other booid species from Messel are related to different New World clades, reinforcing the cosmopolitan nature of the Messel booid fauna. Our analyses indicate that Eoconstrictor was a terrestrial, medium- to large-bodied snake that bore labial pit organs in the upper jaw, the earliest evidence that the visual system in snakes incorporated the infrared spectrum. Evaluation of the known palaeobiology of Eoconstrictor provides no evidence that pit organs played a role in the predator–prey relations of this stem boid. At the same time, the morphological diversity of Messel booids reflects the occupation of several terrestrial macrohabitats, and even in the earliest booid community the relation between pit organs and body size is similar to that seen in booids today.
Body size‐dependent effects on the distribution patterns of phoretic mite species assemblages on Rhynchophorus ferrugineus (Olivier, 1790)
Phoretic mites attach to different body parts of the red palm weevil (RPW), Rhynchophorus ferrugineus (Olivier, 1790), to disperse. However, the question of how the patterns of attachment sites are formed remains intriguing. Here, we examined RPW‐associated phoretic mites in four districts in Northern Portugal (macrohabitat), and investigated the patterns of mite distribution on six body parts of RPW (microhabitat). At the macrohabitat level, we detected seven phoretic mite taxa using the RPW host in each of the four studied districts, all documented for the first time in association with this invasive exotic species in Portugal. However, their relative abundance (species evenness) varied between districts, as did species diversity. All examined weevils carried mites, and the prevalence of the different taxa did not differ between districts or sex of weevils. Measured by mean abundance and degree of aggregation, Centrouropoda sp. proved to be the dominant taxon, while Acarus sp. and Curculanoetus rhynchophorus were considered common subordinate taxa and Uroovobella sp., Mesostigmata, Nenteria extremica and Dendrolaelaps sp. sparse taxa. At the microhabitat level, all taxa were present on all body parts of the RPW; the highest abundance was in a region encompassing the inner surface of the elytra and the membranous hind wings (subelytral space). Analysis of niche overlap revealed that the distribution patterns of phoretic mite taxa on the RPW were not randomly structured. In the subelytral space, interspecific coexistence of mites increased as a function of body size difference with the dominant Centrouropoda sp. We found that in the subelytral space the large dominant species Centrouropoda sp. displaced the larger species Uroobovella sp. and the similarly sized species Nenteria extremica, but coexisted with smaller taxa. We report a high species richness of up to seven phoretic mite taxa, including five unspecified taxa, actively using the red palm weevil as a host in the first study of these organisms in Portugal. We also found body size‐dependent effects on the coexistence or exclusion of phoretic mite taxa that ultimately determine their distribution patterns on the weevil body.
Benthic macrohabitat classification and Madracis spp. coral patch distribution in a deep-sea marine protected area of Colombia
Corales de Profundidad National Natural Park (CPNNP), at the central Colombian Caribbean margin, has an extension of 142.195 ha with depths ranging from 34 to 1,234 m. The CPNNP’s essential ecological value is Madracis spp. as potential structure-forming deep-water coral; this work represents the first footages of these unique habitats for the Colombian Caribbean. In 11 sectors, remote video surveys are conducted, based on a detailed digital elevation model. From these sectors, four cover mesophotic zones (46–169m depth), and seven cover aphotic zones (up to 354m depth). After still images’ description and interpretation, a guide was generated with nine types of macrohabitats surrounding the coral formations of the CPNNP: soft substrate (mud/sand), soft substrate/rubble/rock with solitary corals, coral and shell rubble, rock/ledges with attached fauna, rugged stones with attached fauna, hard substrate with attached fauna, sandstone with attached fauna, soft substrate with burrows, and pockmark with attached fauna. Video transect analysis confirms the occurrence of Madracis spp., with coral patches as the main framework builder of the CPNNP. These patches comprise many clumped 50 to 80 cm high coral colonies that developed over slow slopes, with seafloor elevations between 107 and 233 m and textured soils of soft and not very compact ridges, associated with the macrohabitat sandstone with attached fauna. This information is being used for the management and monitoring of this unique protected area.
Seasonal diversity and abundance distribution of butterflies in Dihing Patkai national park, North East India
Dihing Patkai National Park of North-East India is Dipterocarp-dominated tropical wet evergreen forests in the Indo-Myanmar Hotspot. The diversity and abundance distribution of butterflies in five macrohabitats (Dense Forest, Open Forest, Riparian Vegetation, Roadside Vegetation, and Bamboo Brakes) were studied during the summer, monsoon, and winter seasons from March 2022 to February 2023 in Dihing Patkai National Park. The research work addressed two main research questions: (i) Do the habitats affect the butterflies’ diversity and distribution in Dihing Patkai National Park? (ii) Does the seasonal variation affect the butterflies’ diversity and distribution in Dihing Patkai National Park? The aims of the study were to assess (1) the butterfly species and their distribution across different habitats in Dihing Patkai National Park; and (2) the effect of seasonal variation on butterfly diversity and distribution in Dihing Patkai National Park. A total of 1727 butterflies from 124 species and 6 families, i.e., Hesperiidae, Lycaenidae, Nymphalidae, Papilionidae, Pieridae and Riodinidae, were observed using the Pollard walk technique. The winter season, from October to February, had the highest diversity of butterfly species. Throughout all the seasons, the family Nymphalidae displayed the highest values for α diversity indices. The α diversity indices were highest in the roadside habitat during the summer and monsoon seasons and in open forests in the winter season. An abundance distribution model indicated a significant difference in the abundance of the butterfly species in the open forest and roadside habitat during the summer season and in the open forest during the winter season. The rank-abundance curves showed that the species abundance of butterflies did not differ significantly in all the habitats during the monsoon season. The present study will contribute to the knowledge of seasonal diversity of butterflies and their abundance distribution and will provide baseline information for use in future monitoring of climate change effects in Dipterocarp-dominated tropical wet evergreen forests of Dihing Patkai National Park.
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.
Drivers of wood mouse body condition in Mediterranean agroforestry landscapes
Agriculture and pastureland for cattle grazing are common land uses in Mediterranean landscapes. These activities significantly alter the habitat conditions, affecting the body conditions of wild communities, especially those with low vagility, such as small mammals. We aimed to evaluate how cattle grazing and the habitat composition affected the body condition of the wood mouse Apodemus sylvaticus in a southern Mediterranean agroforestry system using the Scale Mass Index (SMI) as an indicator of individuals condition. To assess variation in body condition, wood mice were live-trapped in a gradient of grazed sites with different stocking intensities, as well in sites excluded to grazing at different time periods (1998, 2004, and 2008). Wood mice body conditions were influenced by both microhabitat and macrohabitat drivers, with sex-biased patterns, while for the females, only the shrub species had an influence (a microhabitat variable); for the males, both the shrub species and the undercover density (and specifically their interaction) were the important drivers (microhabitat and macrohabitat variables). Unexpectedly, the physical condition variation detected between periods was not directly proportional to the exclusion period, but rather, a certain degree of similarity was found between the different sites (sites excluded since 2004 paired with grazed sites). These results suggest that the presence of food and shelter are determinants to the wood mouse’s physical condition: for females, securing food sources enhance the body condition, while for males, the degree of cover, and consequently refuge against predators, seems to be determinant. These results reinforce the need for sustainable landscape management to assure the maintenance of habitat heterogeneity.
Comparative feeding ecology of four syntopic Hypostomus species in a Brazilian southeastern river
Abstract Though their broad distribution in most Brazilian rivers, scarce studies concerning ecological interactions on Hypostomus species are available. This study observes the diet, the trophic interactions and some morphological aspects of four syntopic species of Hypostomus. These fishes were studied at the superior part of the Corumbataí river, at São Paulo state, southeastern Brazil. Analyses focused feeding patterns, their amplitude and whether there happens some food items overlap among the species. Fish were caught using cast nets at some points of the river. Species were chosen according to their local abundance and, so there were four main species: H. albopunctatus, H. ancistroides, H. regani and H. strigaticeps. Nine food items were found: sediments, fungi, diatoms, green algae, Tecamoeba, vegetal debris and invertebrates. There were not significant differences for the feeding pattern among the four Hypostomus species. The feeding niche amplitude has been larger for H. albopunctatus influenced by a larger amount of vegetal debris and invertebrates. Elevated niche overlap was found to happen among the species and also for their trophic morphology. Results may suggest that there is a similar pattern in food taken between four species of Hypostomus analyzed since all consume similar environmental resources and have similar anatomical features. However, a different intake insect larvae and plant material in H. albopunctatus diet indicate differences in local and how this species may be exploring their food compared to the others. Resumo Apesar de sua grande distribuição em todos rios brasileiros, poucos estudos estão disponíveis sobre as interações ecológicas do gênero Hypostomus. Neste estudo nós examinamos a dieta, as interações tróficas e a morfologia de quatro espécies sintópicas de Hypostomus sp. no trecho superior do rio Corumbataí, estado de São Paulo no sudeste do Brasil. As análises focaram o padrão alimentar, a amplitude e sobreposição de nicho alimentar e a correlação entre a dieta com características da morfologia. A captura dos exemplares foi realizada com o uso de redes de arremesso (tarrafa) ao longo do leito do rio. O critério adotado para a escolha baseou-se nas espécies de maior abundância no local, chegando a quatros espécies principais: H. albopunctatus, H. ancistroides, H. regani e H. strigaticeps. Foram encontrados nove itens alimentares: sedimento grosso e fino, hifas de fungos, diatomáceas, algas verdes, algas azuis, Tecamoeba, restos de material vegetal e invertebrados, não havendo diferenças significativas no padrão alimentar entre as quatro espécies de Hypostomus. A amplitude de nicho alimentar foi maior para H. albopunctatus influenciada por um maior consumo de material vegetal e invertebrados. Foram encontrados altos valores de sobreposição de nicho alimentar além de uma similaridade entre a dieta e a morfologia trófica entre as espécies consideradas. Os resultados sugerem que exista um padrão semelhante na tomada de alimento entre as quatros espécies de Hypostomus analisadas, uma vez que, todas consomem recursos alimentares semelhantes e possuam características anatômicas semelhantes. No entanto, uma ingestão diferenciada de larvas de insetos e material vegetal na dieta de H. albopunctatus indicam diferenças nos locais e na forma como esta espécie pode estar explorando o seu alimento em comparação com as demais.
Ecological pattern of lichen species abundance in mixed forests of Eastern Romania
The importance of this study consists in the knowledge of the ecological attributes characteristic to mixed forestry habitats and how they affect the structure of the lichen species abundances. The field activities were performed within five forest habitat types from Moldavia Province, characterised mainly by oak mixed forests, riparian mixed forests and mixed beech forests. The habitat variables, tree variables and the lichen species abundances were analysed to get informations on the structural disimilarities, on the one hand, and relationships on the other hand. Within this study no significant disimilarities were found out from abundance lichen species point of view. The lichen species abundances are a result of interactions between components of their microhabitat and macrohabitat. The correlation analysis pointed out the preferences of lichen species to their host trees, especially Quercus and Fraxinus, altitude and tree level variables as are aspect and mosses coverage. The regression analysis has highlighted that the changes in lichen species abundances are caused by macrohabitat level predictors such as host trees represented by Fraxinus. This study demonstrates that, structure of lichen species is influenced by attributes of mixed forest habitats; therefore maintaining the diversity of tree species and ensuring the continuous occurrence of forestry land is necessary for lichen and their habitat conservation.