scholarly journals Epiphyte type and sampling height impact mesofauna communities in Douglas-fir trees

PeerJ ◽  
2018 ◽  
Vol 6 ◽  
pp. e5699 ◽  
Author(s):  
Alexander R. Young ◽  
Jesse E.D. Miller ◽  
John Villella ◽  
Greg Carey ◽  
William R. Miller

Branches and boles of trees in wet forests are often carpeted with lichens and bryophytes capable of providing periodically saturated habitat suitable for microfauna, animals that include tardigrades, rotifers, nematodes, mites, and springtails. Although resident microfauna likely exhibit habitat preferences structured by fine-scale environmental factors, previous studies rarely report associations between microfaunal communities and habitat type (e.g., communities that develop in lichens vs. bryophytes). Microfaunal communities were examined across three types of epiphyte and three sampling heights to capture gradients of microenvironment. Tardigrades, rotifers, and nematodes were significantly more abundant in bryophytes than fruticose lichen or foliose lichen. Eight tardigrade species and four tardigrade taxa were found, representing two classes, three orders, six families, and eight genera. Tardigrade community composition was significantly different between bryophytes, foliose lichen, fruticose lichen, and sampling heights. We show that microenvironmental factors including epiphyte type and sampling height shape microfaunal communities and may mirror the environmental preferences of their epiphyte hosts.

2021 ◽  
Vol 53 (3) ◽  
pp. 271-282
Author(s):  
Mónika Sinigla ◽  
Erzsébet Szurdoki ◽  
László Lőkös ◽  
Dénes Bartha ◽  
István Galambos ◽  
...  

AbstractThe maintenance of protected lichen species and their biodiversity in general depends on good management practices based on their distribution and habitat preferences. To date, 10 of the 17 protected lichen species of Hungary have been recorded in the Bakony Mts including the Balaton Uplands region. Habitat preferences of three protected Cladonia species (C. arbuscula, C. mitis and C. rangiferina) growing on underlying rocks of red sandstone, basalt, Pannonian sandstone and gravel were investigated by detailed sampling. We recorded aspect, underlying rock type, soil depth, pH and CaCO3 content, habitat type (as defined by the General National Habitat Classification System Á-NÉR), all species of lichen, bryophyte and vascular plants as well as percentage cover of exposed rock, total bryophytes, lichens, vascular plants and canopy, degree of disturbance and animal impacts. Sporadic populations of these species mostly exist at the top of hills and mountains in open acidofrequent oak forests, but they may occur in other habitats, such as closed acidofrequent oak forests, slope steppes on stony soils, siliceous open rocky grasslands, open sand steppes, wet and mesic pioneer scrub and dry Calluna heaths. Cladonia rangiferina was found to grow beneath higher canopy cover than either C. arbuscula or C. mitis in the Balaton Uplands. Furthermore, there were significant differences in canopy cover between occupied and unoccupied quadrats in the case of all three species. Cladonia rangiferina is a good indicator species of natural habitats in Hungary due to its restricted distribution and low ecological tolerance. These results may lead to the adoption of effective conservation methods (e.g. game exclusion, artificial dispersal) in the future.


2018 ◽  
Vol 1 ◽  
Author(s):  
Jenna Keany

Washington, D.C. is home to a remarkable assemblage of troglomorphic amphipods and isopods living in shallow groundwater habitats, the hypotelminorheic. Groundwater from the hypotelminorheic emerges on the surface into low-flowing seepage springs, or “seeps”, which are categorized as having blackened leaves, an underlain layer of clay, a drainage area of less than 10,000 m2, and are situated in slight topographical depressions. Stygobiotic species found in D.C.’s seeps include Crangonyx and Stygobromus amphipods and Caecidotea isopods. One species, Stygobromus hayi, is on the endangered species list and is endemic to the district; however, little is known about their habitat preferences or their distribution. All small water bodies, including rainwater puddles and seepage springs were sampled in national park lands in Southeast D.C. for hypotelminorheic fauna, soil morphology, and water quality indicators such as nitrates, phosphates, radon, pH, DO, and conductivity. Comparing sites with and without stygobionts, all phsysico-chemical parameters were statistically insignificant except for conductivity, which was able to distinguish between stygobiont-rich and stygobiont-poor seeps using logistic regression. Spatially, Crangonyx and Stygobromus amphipods rarely inhabit the same seepage spring, with only three occasions of cohabitation and an expected occurrence of ten. Caecidotea, however, is found in habitats with both amphipods. These results can be explained by either competitive exclusion or the presence of chemical differences in their habitats; however, even if there were some slight differences in their habitats, that still does not exclude competitive exclusion as an explanation. This study highlights new and important findings into the environmental preferences of D.C.’s most cryptic and rare species, and the importance of continued exploration of D.C.’s lesser known park lands.


1999 ◽  
Vol 56 (3) ◽  
pp. 394-406
Author(s):  
Daniel Gaertner ◽  
Mauricio Pagavino ◽  
Jesus Marcano

The influence of Venezuelan skippers' behaviour on the catchability of surface tuna schools was modelled using logistic regressions. Data obtained from observers onboard purse seiners indicated that fishers' fine-scale decisions, such as chasing and setting a school, were influenced by (i) the skipper's skill, (ii) the fishing equipment used (e.g., whether a bird radar was used or not), (iii) the features of the tuna school, and (iv) some environmental factors. The connections among the decisions related to the fishing process and these variables were synthesized in a causal network approach. Results clearly showed that schools (i) composed by fishes under 2 kg and (ii) where biomass was lower than 5 metric tons were disregarded by fishers. Because fishers used these thresholds to decide when to set the net, modifications in their behaviour over the years may introduce serious biases in the analysis of any catch rate and abundance relationship. An average daily activity record of a purse seiner shows the proportion of time spent in searching and in setting activities and highlights the impact that the use of new fishing equipment may have on fishing power.


Water ◽  
2018 ◽  
Vol 10 (11) ◽  
pp. 1625 ◽  
Author(s):  
Shyam Thomas ◽  
Stephanie Melles ◽  
Satyendra Bhavsar

Bioaccumulation of mercury in sport fish is a complex process that varies in space and time. Both large-scale climatic as well as fine-scale environmental factors are drivers of these space-time variations. In this study, we avail a long-running monitoring program from Ontario, Canada to better understand spatiotemporal variations in fish mercury bioaccumulation at two distinct scales. Focusing on two common large-bodied sport fishes (Walleye and Northern Pike), the data were analyzed at fine- and broad-scales, where fine-scale implies variations in bioaccumulation at waterbody- and year-level and broad-scale captures variations across 3 latitudinal zones (~5° each) and eight time periods (~5-year each). A series of linear mixed-effects models (LMEMs) were employed to capture the spatial, temporal and spatiotemporal variations in mercury bioaccumulation. Fine-scale models were overall better fit than broad-scale models suggesting environmental factors operating at the waterbody-level and annual climatic conditions matter most. Moreover, for both scales, the space time interaction explained most of the variation. The random slopes from the best-fitting broad-scale model were used to define a bioaccumulation index that captures trends within a climate change context. The broad-scale trends suggests of multiple and potentially conflicting climate-driven mechanisms. Interestingly, broad-scale temporal trends showed contrasting bioaccumulation patterns—increasing in Northern Pike and decreasing in Walleye, thus suggesting species-specific ecological differences also matter. Overall, by taking a scale-specific approach, the study highlights the overwhelming influence of fine-scale variations and their interactions on mercury bioaccumulation; while at broad-scale the mercury bioaccumulation trends are summarized within a climate change context.


Author(s):  
Tom Swan ◽  
Tanya L Russell ◽  
Thomas R Burkot ◽  
Jianyi Liu ◽  
Scott A Ritchie ◽  
...  

Abstract The global distribution of Aedes albopictus (Skuse) is rapidly expanding which has contributed to the emergence and re-emergence of dengue and chikungunya outbreaks. Improvements in vector surveillance are necessary to facilitate optimized, evidence-based vector control operations. Current trapping technology used to target Ae. albopictus and other Aedes species for vector surveillance are limited in both scale and scope, thus novel tools are required. Here, we evaluated the Male Aedes Sound Trap (MAST) for its capacity to sample male Ae. albopictus. Aims of this study were twofold: 1) to determine the most effective frequency for capturing male Ae. albopictus and 2) to investigate fine-scale variations in male Ae. albopictus abundance. MASTs which produced sound lure frequencies between 500 and 650 Hz captured significantly more male Ae. albopictus than those with sound lure frequencies set to 450 Hz. Further, the higher sound lure frequency of 700 Hz significantly reduced catches relative to 650 Hz. MASTs placed in woodland habitats captured significantly more male Ae. albopictus than MASTs placed near houses. These results provide baseline information for optimizing sound lure frequencies and placement of the MAST to sample male Ae. albopictus in remote areas.


2018 ◽  
Vol 45 (2) ◽  
pp. 194
Author(s):  
K. A. Yao ◽  
E. A. Bitty ◽  
K. B. Kassé ◽  
Y. C. Kouakou ◽  
K. H. Yaokokoré-Beibro ◽  
...  

Context Duikers play a vital role in maintaining forest ecosystems, as both seed dispersers and prey. In West Africa, duikers are also an important source of food and income; however, it is likely that some species are now being hunted at unsustainable levels. So as to contribute to duiker conservation, we used line-transect data and additional information on dung and track counts to estimate relative abundance and establish distribution patterns of forest duikers in Côte d'Ivoire's Dassioko Sud Forest Reserve (DSFR), a poorly known, remnant coastal rainforest. We also collected basic information on hunting pressure. Methods Forest duiker counts were made twice per month from July 2013 to March 2014 on six line transects of varying lengths (5.6–6.7km) and in different regions of the DSFR, representing different habitat types. The number of sightings per kilometre walked, defined as ‘encounter rate', was used to compute an index of relative abundance. We recorded all evidence of poachers and used these data to generate a poaching index (# poaching signs per kilometre) for different habitat types. Key results The DSFR has lost three of seven total forest duiker species and populations of the four remaining species are declining. Encounter rates were greatest for Philantomba maxwellii (0.46 indices km–1) and accounted for 68% of total encounters. Cephalophus niger, C. dorsalis and C. silvicultor were encountered at similar (0.07 indices km–1) but much lower rates. For all species, mean encounter rates were highest in degraded forest (0.38–0.73 indices km–1), followed by secondary (0.2–0.44 indices km–1) and primary (0.19–0.44 indices km–1) forest. Conclusions Of the four forest duiker species still present in the DSFR, the black, bay and yellow-backed duikers are the most affected by anthropogenic pressures. Duiker abundance in the DSFR varies with habitat type. This variation is apparently influenced by differences in forest structure, poaching pressure and proximity to villages. Implications The study provides baseline data for future managing of ungulate populations in the DSFR. We recommend that a biomonitoring study of duiker populations be initiated immediately to help determine population trends, investigate habitat preferences, and help curb illegal hunting activities in this important forest reserve.


2013 ◽  
Vol 72 (2) ◽  
pp. 347-358 ◽  
Author(s):  
Nina Šajna ◽  
Marjana Regvar ◽  
Simona Kaligarič ◽  
Željko Škvorc ◽  
Mitja Kaligarič

Abstract - According to recent molecular analyses of Salicornia, we revised the annual glassworts from the Croatian coast, classified until now only as Salicornia europaea. Two species, a diploid Salicornia patula and a tetraploid S. emerici were recognized. They can be easily distinguished by floral characters, but not only by their habitus, which varies extremely according to environmental factors. Both species differ also in seed morphology. Salicornia patula has dimorphic seeds, with larger central seeds reaching high germination rates. Germination patterns helped to explain the habitat preferences. The species rarely co-occur, however. The rare S. patula occupies drier habitats, on coastal mudflats or sands that are irregularly inundated. It occurs within the assoc. Suaedo maritimae-Salicornietum patulae. Salicornia emerici occupies the lowest coastal mudflats, regularly inundated, where nutrient-rich conditions prevail, and forms an almost monotypical assoc. Salicornietum emerici. Due to the synonymy of S. veneta with S. emerici, we exclude the occurrence of S. veneta in Croatia as an independent taxon.


Author(s):  
Selçuk Altınsaçlı ◽  
Ferda Perçin-Paçal ◽  
Songül Altınsaçlı

AbstractAkdeniz and Akbuk lagoons are part of a shallow coastal ecosystem of great aesthetic and ecological importance, located in Muğla Province in the southern Aegean region of Turkey. In the present study, four expeditions to collect ostracods from these lagoons were conducted in May, July, October, and November of 2008. Benthic samples were obtained monthly and several environmental factors were recorded simultaneously in situ. The ecological preferences of the ostracods were monitored, and qualitative and quantitative samples were collected from three sites in Akdeniz lagoon and two sites in Akbuk lagoon. Three ostracod taxa (Cyprideis torosa, Loxoconcha elliptica and Cytherois fischeri) were identified from the Akdeniz lagoon sampling sites and one species (Cyprideis torosa) from the Akbuk lagoon sampling sites. We present and analyze the dominance and distribution of ostracod assemblages and their relationships to environmental factors: temperature, dissolved oxygen, percentage oxygen saturation, pH, redox potential, salinity, and electrical conductivity) using classification and ordination techniques. Canonical correspondence analysis (CCA) is used to characterize the relationship between ostracods and the environmental variables. Approximately 82% of the correlation between the community composition and environmental variables was explained by the first axis of the CCA ordination for the Akdeniz lagoon. The study revealed that the distribution and population density of ostracod species depends on the physicochemical properties of the environment. The reason for this is that Cyprideis torosa and Loxoconcha elliptica are euryhaline species.


1995 ◽  
Vol 5 (2-3) ◽  
pp. 391-404 ◽  
Author(s):  
Andrew W. Kratter

SummaryHabitat preferences of the Rufous-fronted Antthrush Formicarius rufifrons were studied along the Rio Tambopata in south-eastern Peru. All territories of this threatened species, endemic to lowland forests in the department of Madre de Dios, Peru, contained the near-juxtaposition of two distinct vegetation types: tall floodplain forest with shaded understorey, and more open, second-growth vegetation with a very dense layer of vegetation close to the ground. The latter habitat type was closely associated with disturbances, such as river erosion, tree falls, or human clearings. Two measures of antthrush density were calculated for the study area. A satellite photograph was used to identify appropriate habitat along the upper Rio Tambopata, and using the antthrush density figures, a population size of 100-500 pairs was estimated for this area. This estimate was then used to calculate a global population of 700-3,500 pairs. Approximately 207c of the global population occurs within currently protected areas. The habitat and diet of this species are discussed in relation to two othercongeners.Las preferencias de hábitat de Formicarius rufifrons fueron estudiadas a lo largo del Tambopata en el sureste del Perú. Los territorios de esta amenazada especie, endémica de los bosques tropicales en el depto. de Madre de Dios, están compuestos por dos formaciones vegetales distintas: bosque alto de llanura y vegetación secundaria con un estrato inferior tupido. La vegetación secundaria se debe a los trastornos ecológicos, tales como la erosión fluvial, las caidas de árboles, y también a la tala de bosques. Los limites inferior y superior de densidad (tasa de población) fueron calculados en el área de estudio; los habitats apropriados se identificaron a lo largo del rio a través de imágenes de satélite y se pudo calcular un total de 100-500 parejas para la zona. Se empleó la tasa poblacional, entonces, para calcular la supuesta población global de 700-3,500 parejas. Hoy en dia, aproximadamente 20% de la población global de la especie ocurre dentro de áreas protegidas. Se trata, ademas, el hábitat y la dieta de F. rufifrons en relatión a dos especies congenéricas.


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