Determinants of Habitat Selection by Desert Horned Lizards (Phrynosoma platyrhinos): The Importance of Abiotic Factors Associated with Vegetation Structure

2014 ◽  
Vol 48 (3) ◽  
pp. 306-316 ◽  
Author(s):  
T. A. Scott Newbold ◽  
James A. MacMahon
Keyword(s):  
Habitat Selection ◽  
Vegetation Structure ◽  
Abiotic Factors ◽  
Factors Associated ◽  
Phrynosoma Platyrhinos ◽  
Horned Lizards

Factors influencing the growth of Mougeotia in experimentally acidified mesocosms

2000 ◽  
Vol 57 (3) ◽  
pp. 538-547 ◽  
Author(s):  
Jennifer L Klug ◽  
Janet M Fischer
Keyword(s):  
Inorganic Carbon ◽  
Phytoplankton Community ◽  
Dissolved Inorganic Carbon ◽  
Abiotic Factors ◽  
Minor Role ◽  
Little Rock ◽  
Factors Associated ◽  
Phytoplankton Communities ◽  
Mesocosm Experiments ◽  
Potential Factors

Acidification causes profound changes in species composition in aquatic systems. We conducted mesocosm experiments in three northern Wisconsin lakes (Trout Lake, Little Rock - Reference, Little Rock - Treatment) to test how different phytoplankton communities respond to acidification. Major differences exist among these lakes in water chemistry and phytoplankton community composition. In each lake, three pH treatments (control, press (sustained pH 4.7), and pulse (alternating pH 4.7 and ambient pH)) were maintained for 6 weeks. We observed a striking increase in species in the genus Mougeotia in all systems. Mougeotia is a filamentous green alga often found in acidified lakes. The magnitude of the Mougeotia increase differed among lakes and treatments, and we used an autoregressive model to identify potential factors responsible for these differences. Our results suggest that biotic factors such as competition with other algae played a relatively minor role in regulating Mougeotia dynamics. Instead, pH and abiotic factors associated with changes in pH (e.g., dissolved inorganic carbon) were important predictors of Mougeotia dynamics.

scholarly journals Abiotic factors affecting habitat selection by two invasive gammarids Dikerogammarus villosus and Pontogammarus robustoides

Hydrobiologia ◽  
2017 ◽  
Vol 797 (1) ◽  
pp. 247-263 ◽  
Author(s):  
Jarosław Kobak ◽  
Łukasz Jermacz ◽  
Joanna Marcińczyk ◽  
Ewa Bartoszyńska ◽  
Daria Rutkowska ◽  
...  
Keyword(s):  
Habitat Selection ◽  
Abiotic Factors ◽  
Factors Affecting ◽  
Dikerogammarus Villosus ◽  
Pontogammarus Robustoides

scholarly journals Habitat factors differentiating the occurrence of Ostracoda (Crustacea) in the floodplain of a small lowland River Krąpiel (N-W Poland)

2020 ◽  
pp. 23
Author(s):  
Agnieszka Szlauer-Łukaszewska ◽  
Vladimir Pešić
Keyword(s):  
Abiotic Factors ◽  
River Channel ◽  
Water Bodies ◽  
Oxbow Lakes ◽  
Factors Associated ◽  
Main River ◽  
Main River Channel ◽  
Habitat Factors ◽  
Sediment Sorting ◽  
Physical And Chemical

We analysed the occurrence of ostracods in a small river, taking into account all the types of water bodies in the floodplain − these included helocrenes, oxbow lakes, and ponds, as well as the main river channel. The objective of the study was to investigate the variation in ostracod communities and identify those factors determining species distribution. The environmental factors considered were the type of water body, responsible for 17% of the variance, the physical and chemical water properties (29%), and the biotic and abiotic factors associated with the substrate type (23%). Among the factors associated with the substrate, sediment sorting, plant coverage and insolation were the most important. The ostracod fauna of the helocrenes differed from that of the other water bodies in the floodplain. In the water bodies of the Krąpiel valley and in the main river channel, 33 ostracod species were recorded, of which 26 were found in the main river channel. Refugia in the floodplain were the main source of the diversity and abundance of ostracods in the main river channel. The mean density in the main river channel was very low, at 330 indiv. m−2, while in the water bodies of the floodplain it was the greatest, reaching up to 5568 indiv. m−2.

scholarly journals Biotic and abiotic factors associated with altitudinal variation in plant traits and herbivory in a dominant oak species

2016 ◽  
Vol 103 (12) ◽  
pp. 2070-2078 ◽  
Author(s):  
Luis Abdala-Roberts ◽  
Sergio Rasmann ◽  
Jorge C. Berny-Mier y Terán ◽  
Felisa Covelo ◽  
Gaétan Glauser ◽  
...  
Keyword(s):  
Plant Traits ◽  
Abiotic Factors ◽  
Altitudinal Variation ◽  
Factors Associated ◽  
Biotic And Abiotic Factors

scholarly journals The structural heterogeneity of an urbanised mangrove forest area in southeastern Brazil: Influence of environmental factors and anthropogenic stressors

2016 ◽  
Vol 64 (2) ◽  
pp. 157-172 ◽  
Author(s):  
Gabriela Carvalho Zamprogno ◽  
Mônica Maria Pereira Tognella ◽  
Valeria da Silva Quaresma ◽  
Mercia Barcellos da Costa ◽  
Sávia Soares Pascoalini ◽  
...  
Keyword(s):  
Grain Size ◽  
Organic Matter ◽  
Vegetation Structure ◽  
Abiotic Factors ◽  
Basal Area ◽  
Structural Heterogeneity ◽  
Southeastern Brazil ◽  
Litter Mass ◽  
Anthropogenic Stressors ◽  
Development Levels

Abstract The objective of this study is to evaluate the characteristics of the forest in an urbanised mangrove using vegetation structure and abiotic conditions to distinguish habitat heterogeneity/quality. A total of 16 points in Vitória Bay were selected in the fringe and basin forests. The variables evaluated were height and diameter of the individual trees, basal area, density, dominance, interstitial water, litter mass, grain size, organic matter and anthropogenic influences. The results indicated that the mangrove area, due to suffering intensely from various anthropogenic effects, forests with varying degrees of maturity. Areas more distant from direct human effects had a higher degree of development and environmental quality relative to points closer to urban pressures. Intermediate development levels were also observed, which indicated pulses of environmental change. Human interventions caused alterations in the development of the forest which increased the mortality rate and reduced the diameter and height of the trees. The environmental variables of salinity, organic matter, litter mass, grain size and anthropogenic stressors contributed to the structural patterns. Our data suggest that an analysis of the vegetation structure and the abiotic factors are useful indicators to evaluate habitat quality, thus providing a basis for future management.

scholarly journals Specialization directs habitat selection responses to a top predator in semiaquatic but not aquatic taxa

2021 ◽  
Vol 11 (1) ◽  
Author(s):  
Hana Šigutová ◽  
Filip Harabiš ◽  
Martin Šigut ◽  
Jiří Vojar ◽  
Lukáš Choleva ◽  
...  
Keyword(s):  
Habitat Selection ◽  
Vegetation Structure ◽  
Aquatic Organisms ◽  
Bufo Bufo ◽  
Freshwater Ecosystems ◽  
Similar Response ◽  
Top Predator ◽  
Generalist Species ◽  
Selection Responses ◽  
Floating Macrophytes

AbstractHabitat selectivity has become an increasingly acknowledged mechanism shaping the structure of freshwater communities; however, most studies have focused on the effect of predators and competitors, neglecting habitat complexity and specialization. In this study, we examined the habitat selection of semiaquatic (amphibians: Bufonidae; odonates: Libellulidae) and aquatic organisms (true bugs: Notonectidae; diving beetles: Dytiscidae). From each family, we selected one habitat generalist species able to coexist with fish (Bufo bufo, Sympetrum sanguineum, Notonecta glauca, Dytiscus marginalis) and one species specialized in fishless habitats (Bufotes viridis, Sympetrum danae, Notonecta obliqua, Acilius sulcatus). In a mesocosm experiment, we quantified habitat selection decisions in response to the non-consumptive presence of fish (Carassius auratus) and vegetation structure mimicking different successional stages of aquatic habitats (no macrophytes; submerged and floating macrophytes; submerged, floating, and littoral-emergent macrophytes). No congruence between habitat specialists and generalists was observed, but a similar response to fish and vegetation structure defined both semiaquatic and aquatic organisms. While semiaquatic generalists did not distinguish between fish and fishless pools, specialists avoided fish-occupied pools and had a preferred vegetation structure. In aquatic taxa, predator presence affected habitat selection only in combination with vegetation structure, and all species preferred fishless pools with floating and submerged macrophytes. Fish presence triggered avoidance only in the generalist bug N. glauca. Our results highlight the significance of habitat selectivity for structuring freshwater ecosystems and illustrate how habitat selection responses to a top predator are dictated by specialization and life history.

scholarly journals Habitat use by semi-domesticated reindeer, estimated with pellet-group counts

Rangifer ◽  
2009 ◽  
Vol 27 (2) ◽  
pp. 121 ◽  
Author(s):  
Anna Skarin
Keyword(s):  
Habitat Selection ◽  
Habitat Use ◽  
Rangifer Tarandus ◽  
Spatial Scales ◽  
Abiotic Factors ◽  
Resource Utilisation ◽  
High Quality ◽  
Human Disturbances ◽  
Pellet Group ◽  
Rangifer Tarandus Tarandus

Habitat selection theory predicts that herbivores should select for or against different factors at different spatial scales. For instance, quantity of forage is expected to be a strong factor influencing habitat choice at large scales, while forage quality may be important at finer scales. However, during summer, herbivores such as reindeer (Rangifer tarandus tarandus) can be limited in their grazing time by insect harassment, and do not always have the possibility to select for high quality forage. Human disturbances from hikers, etc., can also have a limiting effect on the possibility for reindeer to graze in high quality foraging habitats. Reindeer habitat selection at the landscape level was investigated through faecal pellet-group counts during the summers of 2002 and 2003 in two reindeer herding districts in Sweden. Resource utilization functions (RUFs) were developed using multiple linear regressions, where the pellet densities were related to vegetation types, topographic features, distances to tourist resorts, and distances to hiking trails. Validations of the models were performed through cross-validation correlations. Results show that high altitudes with high quality forage were important habitats. Areas that offer both snow patches and fresh forage plants for the reindeer were used in relation to their availability. The reindeer also seemed able to habituate to human intervention to a certain extent. The predictive capabilities of the RUF models were high and pellet-group counts seemed well suited to study how abiotic factors affect the habitat use at large temporal and spatial scales Abstract in Swedish / Sammanfattning: Renens användning av sommarbetesområdet, uppskattat med spillningsinventeringar Hierarkiskt habitatval innebär att djur väljer för och emot olika faktorer beroende på den rumsliga skalan. Mängden bete kan t ex spela stor roll för en växtätares habitatval på en stor skala medan kvalitén på betet kan ha större betydelse på en mindre skala. För renar (Rangifer tarandus tarandus), kan betestiden och möjligheten att hitta bra bete sommartid begränsas både på stor och liten skala pga. störningar från insekter och mänsklig aktivitet. Här studerades renarnas val av betesområde på landskapsnivå med hjälp av spillningsinventering under somrarna 2002 och 2003 i två samebyar i Sverige. Spillningstätheten för respektive område och år undersöktes statistiskt med hjälp av multipel linjär regression eller sk ”resource utilisation functions” (RUF). Där relaterades spillningstätheten till vegetationstyp, olika topografiska faktorer, avstånd till vandringsleder, stugplatser och fjällstationer. Resultaten visade att områden högt upp i terrängen med hög beteskvalitet var attraktiva. Vegetationstypen moderat snölega som anses ha hög beteskvalitet användes av renarna i relation till dess förekomst. Däremot verkade renarna undvika områden kring välbesökta fjällstugor och fjällstationer medan de däremot t o m föredrog områden nära vandringsleder. Det kan bero på att vandringslederna går genom attraktiva vegetationstyper. RUF-modellerna hade en hög prediktiv förmåga vilket visar att spillningsinventeringar är användbara när man önskar studera hur djuren använder ett betesområde i relation till olika faktorer på en relativt stor rumslig och temporal skala.

Spatial and seasonal dietary patterns of the desert horned lizard (Phrynosoma platyrhinos): harvester ant specialist or generalist ant feeder?

2009 ◽  
Vol 87 (2) ◽  
pp. 112-123 ◽  
Author(s):  
T.A. Scott Newbold ◽  
James A. MacMahon
Keyword(s):  
Great Basin ◽  
Prey Availability ◽  
Prey Selection ◽  
Feeding Strategy ◽  
Harvester Ants ◽  
Shrub Steppe ◽  
Feeding Specialization ◽  
Phrynosoma Platyrhinos ◽  
Horned Lizards ◽  
Specialist Predators

A suite of factors including prey availability and prey defenses influence prey selection by consumers and ultimately define an animal’s feeding strategy (e.g., generalist or specialist). Here we examined the relationship between availability and selection of ants by the desert horned lizard ( Phrynosoma platyrhinos Girard, 1852) to test the hypothesis that P. platyrhinos are specialist predators on harvester ants, and to investigate which factors influence the prey preference of lizards. Variation in ant availability and lizard diets was assessed using 83 plots established along a Great Basin shrub–steppe bajada in northwestern Utah, USA. Across the study site, 14 of 20 ant species were represented in the lizard diet. However, 70% of that diet consisted of just two species. In contrast to previous studies, P. platyrhinos did not show a disproportionate preference for harvester ants. Instead, larger ants of any species (including harvester ants) were preferentially selected over medium-sized and smaller ants. These findings suggest that desert horned lizards demonstrate an opportunistic feeding strategy in which lizards select ants based on their body size and abundance. More generally, these results emphasize the importance of assessing predator response across naturally varying gradients in prey availability to evaluate feeding specialization.

scholarly journals Retrospective Study of Campylobacter Infection in a Zoological Collection

2007 ◽  
Vol 74 (5) ◽  
pp. 1332-1338 ◽  
Author(s):  
Maged M. Taema ◽  
James C. Bull ◽  
Shaheed K. Macgregor ◽  
Edmund J. Flach ◽  
Wayne S. Boardman ◽  
...  
Keyword(s):  
Bacterial Infections ◽  
Abiotic Factors ◽  
Wild Animal ◽  
Factors Associated ◽  
Zoological Society ◽  
Animal Populations ◽  
Concurrent Infections ◽  
Weak Negative Correlation ◽  
The Mean ◽  
Campylobacter Infection

ABSTRACT Little is known about the epidemiology of Campylobacter spp. in wild animal populations. However, zoological collections can provide valuable insights. Using records from the Zoological Society of London Whipsnade Zoo compiled between 1990 and 2003, the roles of a range of biotic and abiotic factors associated with the occurrence of campylobacteriosis were investigated. The occurrence of campylobacteriosis varied widely across host taxonomic orders. Furthermore, in mammals, a combination of changes in both rainfall and temperature in the week preceding the onset of gastroenteritis were associated with isolation of Campylobacter from feces. In birds, there was a weak negative correlation between mean weekly rainfall and isolation of Campylobacter from feces. Importantly, in birds we found that the mean weekly rainfall 3 to 4 weeks before symptoms of gastroenteritis appeared was the best predictor of Campylobacter infection. Campylobacter-related gastroenteritis cases with mixed concurrent infections were positively associated with the presence of parasites (helminths and protozoans) in mammals, while in birds Campylobacter was associated with other concurrent bacterial infections rather than with the presence of helminths and protozoans. This study suggests that climatic elements are important factors associated with Campylobacter-related gastroenteritis. Further investigations are required to improve our understanding of Campylobacter epidemiology in captive wild animal populations.

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