Journal articles on the topic 'Habitat'
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Averlant, Philippe, and Richard Sabatier. "Habiter, habitant, habitat." VST - Vie sociale et traitements 97, no. 1 (2008): 26. http://dx.doi.org/10.3917/vst.097.0026.
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Habel, Jan Christian, and Frank E. Zachos. "Habitat fragmentation versus fragmented habitats." Biodiversity and Conservation 21, no. 11 (August 19, 2012): 2987–90. http://dx.doi.org/10.1007/s10531-012-0349-4.
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Virgl, John A., and François Messier. "Assessment of source-sink theory for predicting demographic rates among habitats that exhibit temporal changes in quality." Canadian Journal of Zoology 78, no. 8 (August 1, 2000): 1483–93. http://dx.doi.org/10.1139/z00-066.
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Within the framework of Pulliam's source-sink model we tested predictions of habitat-specific demography on a "closed" population of muskrats (Ondatra zibethicus L.) occupying three contiguous habitats that exhibited temporal changes in quality and quantity. We were able to distinguish between dispersal among habitats and mortality within each habitat, and induce temporal variation in operational-habitat availability and suitability by manipulating water level. Temporal variation in population size and density among habitats supported the source-sink model and was primarily associated with habitat-specific survival rates. For example, the mean annual over-winter mortality rate of individuals in the principal source habitat (0.87) was less than in the sink habitat (0.94), and subsequently the mean annual finite rate of increase (λ) was positive in the source habitat (λ = 1.41) and negative in the sink habitat (λ = 0.90). The high recruitment rate of juveniles in the prime habitat during autumn was also associated with significant emigration of juveniles from this habitat. Emigration of adults among habitats provided support for the role of spacing behaviour in regulating the breeding density of muskrats in prime habitat. However, in contrast to the assumption of source-sink theory, year-to-year variation in survival rate in the more marginal habitats appeared to be explained more by temporal changes in habitat suitability than by density. Significant emigration of juveniles from the sink habitat was not predicted and was largely dependent on current habitat conditions. In addition, the mean annual emigration rate was lowest in the principal source habitat (0.30) and highest in the more marginal habitats (0.62). Failure to detect directional emigration from prime to marginal habitats in the spring, as predicted by the source-sink model, was likely due to declining local population size. In environments where spatial differences in habitat quality are not static, and annual change in local population size is largely independent of density, current source-sink models must be modified to better predict individual dispersal strategies.
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PROOROCU, Marian, and Cristina Maria AVRAM. "Evaluation of Anthropical Pressures on Community Interest Habitats and Species in Natura 2000 Cold Someș." Bulletin of University of Agricultural Sciences and Veterinary Medicine Cluj-Napoca. Agriculture 77, no. 1 (May 24, 2020): 7. http://dx.doi.org/10.15835/buasvmcn-agr:2019.0026.
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The list of habitats of community interest within the Natura 2000 site ROSCI0233, as provided in the Natura 2000 standard, comprises 8 habitats of community interest. Two important activities were carried out: identification and inventory of habitats and species and assessment of negative influences that could affect the natural distribution area, the structure and functions. The assessment of the conservation status has highlighted the existence of significant anthropogenic pressures on some habitats (deforestation, land use change), which led to their unfavorable conservation status (habitat 9410, habitat 91D0*, habitat 91E0*, habitat 9110, habitat 9130).
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Rosenfeld, Jordan S., and Todd Hatfield. "Information needs for assessing critical habitat of freshwater fish." Canadian Journal of Fisheries and Aquatic Sciences 63, no. 3 (March 1, 2006): 683–98. http://dx.doi.org/10.1139/f05-242.
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The core assumptions of critical habitat designation are a positive relationship between habitat and population size and that a minimum habitat area is required to meet a recovery target. Effects of habitat on population limitation scale from (i) effects on performance of individuals (growth, survival, fecundity) within a life history stage, to (ii) limitation of populations by habitats associated with specific life history stages, and (iii) larger-scale habitat structure required for metapopulation persistence. The minimum subset of habitats required to achieve a recovery target will depend on the extent, quality, and spatial configuration of habitats available to sequential life history stages. Although populations may be limited by available habitat for a single life history stage, altering habitat quality for subsequent stages will also affect individual survival and population size, providing multiple leverage points within a life history for habitat management to achieve recovery targets. When habitat-explicit demographic data are lacking, consequences of uncertainty in critical habitat assessment need to be explicit, and research should focus on identifying habitats most likely to be limiting based on species biology.
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Pratt, Thomas C., and Karen E. Smokorowski. "Fish habitat management implications of the summer habitat use by littoral fishes in a north temperate, mesotrophic lake." Canadian Journal of Fisheries and Aquatic Sciences 60, no. 3 (March 1, 2003): 286–300. http://dx.doi.org/10.1139/f03-022.
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Compensation measures in response to Fisheries and Oceans Canada (DFO) Policy for the Management of Fish Habitat includes provisions for habitat creation and enhancement. Thus, an assessment of nearshore habitat utilization patterns by fishes is needed to put DFO compensation measures in the context of the "no net loss of the productive capacity of fish habitat" directive. Measures of abundance, richness, and diversity of fishes were compared across nine habitat types in a lake using rapid visual underwater assessment. Multivariate analyses separated habitats into three groups and identified two distinct species assemblages. Most species were associated with macrophytes, but a few were primarily associated with rocky substrate. Shallow mud (open) habitats contained significantly fewer species and had lower mean scores and diversity than all other habitat types. Rocky habitats had lower mean scores and diversity than some vegetated habitat types containing similar fish assemblages. Surprisingly, within-site fish assemblage heterogeneity was similar to among-site heterogeneity, and among-habitat heterogeneity was lower than within-habitat heterogeneity, further supporting our inability to distinguish among vegetated habitat types. Our results suggest that habitat heterogeneity is critical in maintaining diverse communities and that compensation measures should account for differences in fishhabitat associations among varied habitats.
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Noguchi, Hideyuki, Akira Itoh, Takashi Mizuno, Kriangsak Sri-ngernyuang, Mamoru Kanzaki, Sakhan Teejuntuk, Witchaphart Sungpalee, et al. "Habitat divergence in sympatric Fagaceae tree species of a tropical montane forest in northern Thailand." Journal of Tropical Ecology 23, no. 5 (August 16, 2007): 549–58. http://dx.doi.org/10.1017/s0266467407004403.
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Spatial distributions of many tropical trees are skewed to specific habitats, i.e. habitat specialization. However, habitats of specialist species must be divergent, i.e. habitat divergence, to coexist in a local community. When a pair of species specialize in the same habitat, i.e. habitat convergence, they could not coexist by way of habitat specialization. Thus, analyses of habitat divergence, in addition to habitat specialization, are necessary to discuss coexistence mechanisms of sympatric species. In this study, the habitat specialization and habitat divergence along topographic gradients of eight sympatric tree species of the Fagaceae were studied in a 15-ha study plot in a tropical lower montane forest in northern Thailand. A statistical test with torus shift randomizations for 9673 trees of Fagaceae revealed significantly biased distributions for all of the species, for at least one of the four topographic variables used: elevation, slope inclination, aspect and convexity. Slope convexity was the most critical topographic variable, along which all but one species had significantly skewed distributions. Out of 112 possible combinations of species pairs and topographic variables, 18 (16%) and two pairs (1.8%) showed significant habitat divergence and habitat convergence, respectively. The observed habitat divergence alone could not completely explain the coexistence of the eight species. There was a gradation in the habitat position of each species, with relatively large overlaps between species distributed in similar habitats, and small overlaps between species associated with contrasting habitats, respectively. The gradual changes in the habitats of the species suggested that dividing the species into a small number of distinct habitat groups, such as ridge and valley specialists, would not be straightforward.
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Robinson, B. G., K. W. Larsen, and H. J. Kerr. "Natal experience and conspecifics influence the settling behaviour of the juvenile terrestrial isopod Armadillidium vulgare." Canadian Journal of Zoology 89, no. 8 (August 2011): 661–67. http://dx.doi.org/10.1139/z11-030.
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Cues used by dispersing juveniles to assess habitat quality can be based on public information available to all individuals or on private information obtained from experience in the natal habitat. The presence of conspecifics (public information) and natal habitat quality (private information) have been shown to influence habitat preferences in many species, but the relative importance of these two cue types is seldom investigated. We examined whether habitat quality relative to the natal habitat had a stronger influence on the settling decisions of the juvenile terrestrial isopod Armadillidium vulgare (Latreille, 1804), than sign of conspecifics. We raised juvenile A. vulgare in either high- or low-quality habitats and then observed how the presence of conspecific sign influenced their preference for each of these habitats. When conspecific sign was absent, juveniles preferred high-quality habitat, regardless of their natal habitat. When the low-quality habitat was treated with conspecific sign, juveniles born on low-quality habitat continued to prefer the high-quality habitat, but juveniles raised on high-quality habitat displayed no preference. This suggests juvenile isopods respond to these cues hierarchically: they first search for habitats higher in quality than their natal habitat and then cue into conspecific sign when the preferred habitat is unavailable.
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Huang, Yen-Hua, Hendrina Joel, Martina Küsters, Zoe R. Barandongo, Claudine C. Cloete, Axel Hartmann, Pauline L. Kamath, et al. "Disease or drought: environmental fluctuations release zebra from a potential pathogen-triggered ecological trap." Proceedings of the Royal Society B: Biological Sciences 288, no. 1952 (June 2, 2021): 20210582. http://dx.doi.org/10.1098/rspb.2021.0582.
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When a transmission hotspot for an environmentally persistent pathogen establishes in otherwise high-quality habitat, the disease may exert a strong impact on a host population. However, fluctuating environmental conditions lead to heterogeneity in habitat quality and animal habitat preference, which may interrupt the overlap between selected and risky habitats. We evaluated spatio-temporal patterns in anthrax mortalities in a plains zebra ( Equus quagga ) population in Etosha National Park, Namibia, incorporating remote-sensing and host telemetry data. A higher proportion of anthrax mortalities of herbivores was detected in open habitats than in other habitat types. Resource selection functions showed that the zebra population shifted habitat selection in response to changes in rainfall and vegetation productivity. Average to high rainfall years supported larger anthrax outbreaks, with animals congregating in preferred open habitats, while a severe drought forced animals into otherwise less preferred habitats, leading to few anthrax mortalities. Thus, the timing of anthrax outbreaks was congruent with preference for open plains habitats and a corresponding increase in pathogen exposure. Given shifts in habitat preference, the overlap in high-quality habitat and high-risk habitat is intermittent, reducing the adverse consequences for the population.
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Mao, Zhihui, Fang Ding, Lilai Yuan, Yan Zhang, Zhaohui Ni, Yingren Li, Lin Wang, and Yunfeng Li. "The Classification of Riparian Habitats and Assessment of Fish-Spawning Habitat Suitability: A Case Study of the Three Gorges Reservoir, China." Sustainability 15, no. 17 (August 23, 2023): 12773. http://dx.doi.org/10.3390/su151712773.
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After the completion of the Three Gorges Reservoir (TGR), there was a significant and drastic transformation of the original river habitat. These changes led to the loss of the original fish habitat and the emergence of a new habitat. To effectively classify and assess fish-spawning habitats in the TGR, a novel coastal complexity index (CCI) was developed. The CCI was formulated utilizing satellite remote sensing data and considering the river coastal line and river centerline on the river-reach scale. By integrating the CCI with river morphology, five river habitats were identified: the backwater bay, point bar, straight river channel, convex-bank point bar, and concave-bank deep pool. In order to evaluate the suitability of these habitats for sticky-egg-spawning fish, a single-factor habitat suitability curve was constructed using three key habitat factors: the CCI, slope, and vegetation coverage. This process involved the employment of two distinct methods: the habitat utilization method and the habitat preference method. The former only considered the survey data of spawning grounds, while the latter integrated the overall distribution of habitats in the TGR. Subsequently, a habitat suitability index (HSI) was established to assess the overall suitability of the identified habitats for sticky-egg-spawning fish. The results demonstrated a high classification accuracy, with the backwater bay representing the most prevalent habitat type, accounting for 43.31% of the total habitat types. When considering slope and vegetation coverage, the optimal ranges obtained through the two habitat suitability analysis methods were similar. However, for the CCI, there were variations in the optimal ranges obtained using the two methods. The habitat utilization method indicated an optimal interval of 2–4, while the habitat preference method provided an optimal interval of 4–8. Nonetheless, the assessment results for the spawning habitats’ suitability using both methods yielded essentially identical outcomes. Specifically, the backwater bay, convex-bank point bar, and concave-bank deep pool habitats exhibited higher suitability for spawning than point bar and straight river channel habitats. Further analysis revealed that approximately 75% of the 230 identified backwater bays were categorized as high-quality or higher-quality spawning habitats. In the time since this research was conducted, its findings have served as a theoretical foundation for the protection of aquatic biological resources and habitats.
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Meynecke, J. O. "Coastal habitat connectivity ? implications for declared fish habitat networks in Queensland, Australia." Pacific Conservation Biology 15, no. 2 (2009): 96. http://dx.doi.org/10.1071/pc090096.
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Estuaries are widely recognized as key habitats supporting nearshore secondary production and catch of commercial fisheries. In Queensland, some of these coastal marine habitats are protected by the declared fish habitat programme run by the Department of Primary Industries and Fisheries. Expected environmental changes for Australian estuarine systems include reduced freshwater flow, increased sedimentation and with them, a loss of connectivity. At present, the relationship between the protected declared fish habitat and habitat connectivity remains unknown. By comparing long term coastal fish catch data with geomorphic characteristics of coastal habitats structural connectivity was previously identified as a potential driver of commercial fish catch in Queensland. An ecology landscape approach was used for this study to identify potential fish habitat hotspots along the coastline of Queensland thus allowing better defined networks of declared fish habitats. A comparison between this approach and the current declared fish habitats demonstrated potential deficits and provided important insights for fisheries management. Declared fish habitats should be placed in coastal habitats with high structural connectivity to ensure sustainability of fisheries in light of environmental changes.
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Halliday, William D., Caroline Bourque, and Gabriel Blouin-Demers. "Food quality influences density-dependent fitness, but not always density-dependent habitat selection, in red flour beetles (Coleoptera: Tenebrionidae)." Canadian Entomologist 151, no. 6 (August 5, 2019): 728–37. http://dx.doi.org/10.4039/tce.2019.47.
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AbstractDensity-dependent habitat selection models inherently rely on the negative relationship between population density and mean fitness in different habitats. Habitats differing in quality, such as different food sources or habitat structure, can have different strengths of density-dependent relationships, which can then affect patterns of density dependence in habitat selection. We tested the hypothesis that density dependence in fitness dictates the patterns in density-dependent habitat selection: individuals should prefer higher-quality habitat over lower-quality habitat. We used controlled experiments with red flour beetles (Tribolium castaneum (Herbst) (Coleoptera: Tenebrionidae)) to measure density dependence of fitness and to examine density-dependent habitat selection by beetles in wheat (Triticum Linnaeus (Poaceae)), corn (Zea mays Linnaeus (Poaceae)), and soy (Glycine max (Linnaeus) Merrill (Fabaceae)) flour habitats. Despite large differences in fitness between habitats (fitness was the highest in wheat flour, lower in corn flour, and zero in soy flour), beetles showed only weak preference for wheat over corn flour and for corn over soy flour, but showed strong preference for wheat over soy flour. These preferences were the strongest at low density. This study gives insight into the relationship between habitat quality and density-dependent habitat selection in flour beetles.
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Paterson, George B., Gill Smart, Paul McKenzie, and Sally Cook. "Prioritising sites for pollinators in a fragmented coastal nectar habitat network in Western Europe." Landscape Ecology 34, no. 12 (October 30, 2019): 2791–805. http://dx.doi.org/10.1007/s10980-019-00884-x.
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Abstract Context Habitat loss and fragmentation contribute significantly to pollinator decline and biodiversity loss globally. Conserving high quality habitats whilst restoring and connecting remnant habitat is critical to halt such declines. Objectives We quantified the connectivity of pollinator habitats for a generic focal species (GFS) which represented three groups of pollinators in an existing coastal nectar habitat network. Subsequently, in partnership with a conservation agency, we modelled an improved landscape that identified priority habitat patches to increase connectivity for pollinators. Methods We selected 4260 pollinator habitats along an 80 km section of coastland in Scotland using Phase 1 habitat data. A GFS represented three vulnerable European pollinator groups while graph theory and spatial metrics were used to identify optimal sites that could enhance habitat connectivity. Results Higher dispersing species experienced greater habitat connectivity in the improved landscape and habitat availability increased substantially in response to small increases in habitat. The improved landscape revealed important habitat patches in the existing landscape that should be protected and developed. Conclusions Our findings highlight that optimal landscapes can be designed through the integration of habitat data with spatial metrics for a GFS. By adopting this novel approach, conservation strategies can be targeted in an efficient manner to conserve at-risk species and their associated habitats. Integrating these design principles with policy and practice could enhance biodiversity across Europe.
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Ravi, Harshan, Olya Stringfield, Gustavo De Leon, Sandra Johnston, Russell Rockne, Behnam Badie, Christine E. Brown, Kristin Swanson, Robert Gatenby, and Natarajan Raghunand. "NIMG-74. MULTIPARAMETER MRI INVESTIGATION OF HIGH-GRADE GLIOMA RESPONSE TO CAR T CELL IMMUNOTHERAPY." Neuro-Oncology 21, Supplement_6 (November 2019): vi178. http://dx.doi.org/10.1093/neuonc/noz175.743.
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Abstract INTRODUCTION Immunotherapy with engineered CAR T cells is a promising new therapy for glioblastoma, for which predictive and prognostic biomarkers are needed to inform effective intervention. Recently, our group analyzed standard-of-care (SOC) MRI images of long-term and short-term glioblastoma survivors and identified six intratumoral “habitats” of which “Habitat 6” was correlated with survival at diagnosis in high-grade glioma. Based on the MRI characteristics of “Habitat 6”, viz. high enhancement and high edema, we hypothesized that it could be a marker of tumor immune infiltrates. We are studying longitudinal changes in tumor “habitat” composition on MRIs of subjects with recurrent high-grade glioma treated with CAR T cells engineered to target IL13Ra2. METHODS MRI scans of the brain were acquired in 6 subjects at 3.0 T at baseline and various times before and after initiation of CAR T cell therapy. FLAIR, T1W and T1W-CE MRI images were registered to T2W images and six intratumoral “habitats” were computed as per our recently published methodology. The six habitats generated at the end of the tumor segmentation process were: “Habitat 1” (low FLAIR, low enhancement), “Habitat 2” (high FLAIR, low enhancement), “Habitat 3” (low FLAIR, medium enhancement), “Habitat 4” (high FLAIR, medium enhancement), “Habitat 5” (low FLAIR, high enhancement), and “Habitat 6” (high FLAIR, high enhancement). RESULTS Analysis of temporal changes in the six “habitats” shows an initial increase in both “Habitat 4” and “Habitat 6” following CAR T cell therapy initiation. Subjects with higher absolute volumes of “Habitat 6” at the baseline (pre-treatment) showed longer overall survival. Overall survival is a function of absolute “Habitat 6” volume at baseline, its direction of change immediately post-therapy, the duration of any increase in “Habitat 6” post-treatment, and the “Habitat 6” to “Habitat 4” ratio. Additional subjects are being evaluated to further understand these preliminary observations.
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Jiang, Xuewei, Fei Chen, Jingjing Yang, Zhengli Zhou, Lu Han, and Ruiheng Lyu. "Decomposition of Foliar Litter from Dominant Plants of Desert Riparian Forests in Extremely Arid Regions." Forests 15, no. 6 (May 30, 2024): 949. http://dx.doi.org/10.3390/f15060949.
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Litter decomposition is important for understanding the effects of habitat on nutrient cycling. In this study, we investigated the decomposition characteristics, decomposition variability, and regulatory factors restricting the decomposition rates of leaf litter in three different habitats: a flood disturbance habitat, an arid habitat, and a high-salinity habitat. The litter decomposition rates of the habitats decreased in the following order: flood disturbance habit > arid habitat > high-salinity habitat. The organic carbon, total nitrogen, and lignin residues of the litter during the decomposition period were highest in the high-salinity habitat. The litter quality was the main regulator of the release of phosphorus and cellulose residues, which exhibited different release processes and patterns in these three habitats. The litter decomposition coefficient was negatively correlated with litter carbon residue in the flood disturbance habitats, the lignocellulose index in the arid habitats, and soil urease in the high-salinity habitats. It was positively correlated with the lignocellulose index in flood disturbance habitats and litter carbon residue in high-salinity habitats. The litter quality in the flood disturbance area played a significant role in litter decomposition, while environmental quality and litter quality were the dominant factors under arid and high-salt conditions. Litter quality in the flood disturbance area played a significant role in litter decomposition, while both environmental quality and litter quality were the dominant factors under arid and salt conditions.
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Lemieux Lefebvre, S., M. Landry-Cuerrier, and M. M. Humphries. "Identifying the critical habitat of Canadian vertebrate species at risk." Canadian Journal of Zoology 96, no. 4 (April 2018): 297–304. http://dx.doi.org/10.1139/cjz-2016-0304.
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Identification of critical habitat is central to major conservation laws protecting endangered species in North America and around the world. Yet the actual ecological research that is required to identify which habitats are critical to the survival or recovery of species is rarely discussed and poorly documented. Here we quantitatively assess the information and methods used to identify critical habitat in the recovery strategies of 53 vertebrates at risk in Canada. Of the critical habitat identifications assessed, 17% were based on habitat occupancy information, 28% on habitat characteristics and (or) functions, and 40% assessed habitat suitability by linking functional use and biophysical characteristics. However, only 15% of the recovery strategies we evaluated examined relationships between habitat and population viability, abundance, individual fitness, or survival. Furthermore, the breadth of evidence used to assess critical habitats was weaker among long-lived taxa and did not improve over time. Hence, although any approach used to identify critical habitat is likely to be a step in the right direction in minimally protecting and maintaining habitats supporting critical life-cycle processes, there is a persistent gap between the widely recognized importance of critical habitat and our ability to quantitatively link habitats to population trends and individual fitness.
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Milne, Grant A., Jennifer Miksis-Olds, Alyssa Stasse, Bo-Young Lee, Dylan Wilford, Shaurya Baruah, and Bonnie Brown. "Using the Soundscape Code to compare coastal marine habitats in the Gulf of Maine." Journal of the Acoustical Society of America 154, no. 4_supplement (October 1, 2023): A171. http://dx.doi.org/10.1121/10.0023165.
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Identifying similarities and differences in soundscape properties among coastal marine habitats is valuable for determining indicators of habitat composition, assessing functional connectivity among habitats, and informing management decisions regarding the soundscapes of these habitats. The “Soundscape Code,” proposed and developed by Dylan Wilford, enables rapid calculation of values for four salient soundscape properties: amplitude, impulsivity, periodicity, and dissimilarity. This enables multivariate statistical analyses to quantitatively compare soundscapes in different habitat types and geographic regions. The objective of the current work was to determine whether geographic region or habitat type accounts for more variability in coastal soundscape properties. Passive acoustic recordings were acquired in three different habitat types (sand, macroalgae, and eelgrass dominated substrates), in each of four different geographic locations along the New Hampshire/Maine coastline, to compare the soundscapes of habitats with varied biological and geophysical substrate composition. Results indicate that geographic location accounted for more variability in the soundscapes than habitat type, suggesting that habitats’ local connectivity outweighs acoustic and biological uniformity of the same habitat type over broader spatial scales. Future analyses will incorporate metagenomic data for predictive modeling of habitat composition through the combined use of passive acoustic monitoring and metabarcoding of seawater samples.
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Longmire, KS, RD Seitz, A. Smith, and RN Lipcius. "Saved by the shell: Oyster reefs can shield juvenile blue crabs Callinectes sapidus." Marine Ecology Progress Series 672 (August 19, 2021): 163–73. http://dx.doi.org/10.3354/meps13781.
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Juvenile blue crabs Callinectes sapidus use seagrass and other structured habitats as refuges from predation. Oyster reef habitats provide structural complexity that may offer refuge, but the value of these habitats for juvenile blue crabs has not been examined. We quantified survival of juvenile C. sapidus in structured oyster reef habitat versus unstructured soft-bottom habitat. In a field tethering experiment in the York River, lower Chesapeake Bay (USA), juvenile C. sapidus (10-50 mm carapace width [CW]) were tethered in sand (n = 40) or oyster reef (n = 39) habitats at subtidal sites 1-2 m deep. An underwater camera system was used to record predation activity during 24 h trials. Juvenile crab survival was significantly higher on the oyster reef habitat (53.8%) than on bare sand (15.0%), and tended to increase with crab CW in both habitats. The main successful predators on juvenile blue crabs were northern pufferfish Sphoeroides maculatus in the oyster reef habitat and adult blue crabs in the sand habitat. The high survival rate of juvenile C. sapidus in oyster reef habitats suggests that oyster reefs include physical habitat complexity that may offer refuge from predators. Restored and natural oyster reefs could provide an alternative nursery habitat for juvenile blue crabs, expanding the ecosystem services provided by restored oyster reefs.
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Hastaril, Belinda, and Muhammad Arief Soendjoto. "Studi Variasi Tingkat Keanekaragaman Jenis Burung pada Berbagai Tipe Habitat di Areal Konservasi Perkebunan Sawit PT.MSM, Wilmar Plantation, Kalteng." Daun: Jurnal Ilmiah Pertanian dan Kehutanan 2, no. 1 (June 1, 2015): 1–11. http://dx.doi.org/10.33084/daun.v2i1.167.
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High Conservation Value Areas (HCVA) in palm oil plantation is one of the efforts to reduce the negative impoct of oil palm plantations on biodiversity. The purpose of this study was to to identify bird species in dffirent types of habitats in the conserration area of oil palm plantations, calculate and compare the diversity of bird species and how is the relations with vegetation as habitat componen\ the study location at PT. MSM, Wilmar Plantation Central Kalimantan. The results showed the diversity value of birds and vegetation hos a positive relationship. Forested habitat v,ith heterogeneous vegetation presenting a higher value of diversity bird species than homogeneous vegetation hobitat. The highest diversity of
bird species is the habitot of swampforests (H'3,70) lowland forest (H'3,69), heath forest (H'3,59) and the lowest is the habitat of palm plantatioru (H' 2,60).
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Rango, Jessamy J. "A Survey of Ant Species in Three Habitats at Mount St. Helens National Volcanic Monument." Psyche: A Journal of Entomology 2012 (2012): 1–9. http://dx.doi.org/10.1155/2012/415183.
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Ants were surveyed in three habitats at Mount St. Helens in 2008. The area most impacted by the 1980 eruption is the Pumice Plain. Less impacted is the Blowdown Zone where trees were toppled due to the blast. Two habitats were surveyed in the Pumice Plain varying in vegetation density (Pumice Plain Low-Vegetation (PPLV) and Pumice Plain High-Vegetation (PPHV)), and one habitat was surveyed in the Blowdown Zone (BDZ). Ten ant species were collected with the most species collected from the BDZ habitat and the least from the PPLV habitat. Ant abundance was higher at the BDZ and PPHV habitats than at the PPLV habitat. Ant biodiversity was highest at the BDZ habitat than at the PPHV and PPLV habitats. Significant correlations between ant community parameters and plant community parameters were also found. Few plants in the PPLV habitat may contribute to the lack of ants. High ant species richness at the BDZ habitat may be due to complex plant architecture. Results from this study suggest that ants are important focal species in tracking biotic recovery following disturbances.
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Ossola, Alessandro, Michael A. Nash, Fiona J. Christie, Amy K. Hahs, and Stephen J. Livesley. "Urban habitat complexity affects species richness but not environmental filtering of morphologically-diverse ants." PeerJ 3 (October 22, 2015): e1356. http://dx.doi.org/10.7717/peerj.1356.
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Habitat complexity is a major determinant of structure and diversity of ant assemblages. Following the size-grain hypothesis, smaller ant species are likely to be advantaged in more complex habitats compared to larger species. Habitat complexity can act as an environmental filter based on species size and morphological traits, therefore affecting the overall structure and diversity of ant assemblages. In natural and semi-natural ecosystems, habitat complexity is principally regulated by ecological successions or disturbance such as fire and grazing. Urban ecosystems provide an opportunity to test relationships between habitat, ant assemblage structure and ant traits using novel combinations of habitat complexity generated and sustained by human management. We sampled ant assemblages in low-complexity and high-complexity parks, and high-complexity woodland remnants, hypothesizing that (i) ant abundance and species richness would be higher in high-complexity urban habitats, (ii) ant assemblages would differ between low- and high-complexity habitats and (iii) ants living in high-complexity habitats would be smaller than those living in low-complexity habitats. Contrary to our hypothesis, ant species richness was higher in low-complexity habitats compared to high-complexity habitats. Overall, ant assemblages were significantly different among the habitat complexity types investigated, although ant size and morphology remained the same. Habitat complexity appears to affect the structure of ant assemblages in urban ecosystems as previously observed in natural and semi-natural ecosystems. However, the habitat complexity filter does not seem to be linked to ant morphological traits related to body size.
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Cockell, Charles S. "Types of habitat in the Universe." International Journal of Astrobiology 13, no. 2 (February 21, 2014): 158–64. http://dx.doi.org/10.1017/s1473550413000451.
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AbstractFrom a biological point of view, all environments in the Universe can be categorized into one of three types: uninhabitable, uninhabited habitat or inhabited habitat. This paper describes and defines different habitat types in the Universe with a special focus on environments not usually encountered on the Earth, but which might be common on other planetary bodies. They include uninhabited habitats, subtypes of which are sterile habitats and organic-free habitats. Examples of the different types of environments are provided with reference to the Eyjafjallajökull, Iceland. These habitat types are used to identify testable hypotheses on the abundance of different habitats and the distribution of life in the Universe.
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Liford, A. N., and K. K. Cecala. "Does riparian disturbance alter stream amphibian antipredator behaviors?" Canadian Journal of Zoology 95, no. 2 (February 2017): 75–79. http://dx.doi.org/10.1139/cjz-2016-0113.
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Ecological traps occur when a species makes maladaptive habitat-selection decisions. Human-modified environments including deforested riparian habitats can change how organisms respond to environmental cues. Stream amphibians alter their habitat selection in response to abiotic cues associated with riparian clearing, but little research exists to determine if behavioral shifts to abiotic cues may make them more susceptible to predation. To evaluate if deforested habitats create ecological traps, we studied habitat-selection behavior of larval Black-bellied Salamander (Desmognathus quadramaculatus (Holbrook, 1840)) when given conflicting environmental cues. We also evaluated the potential for learning or adaptation to cues in deforested reaches by evaluating individuals from forested and deforested reaches. We anticipated that individuals from deforested reaches would make adaptive antipredator choices when presented with well-lit habitat, whereas individuals from forested reaches would select shaded habitat closer to a predator. We found that habitat origin, light, and predator presence all interacted to influence habitat selection. Although individuals from forested habitats selected shaded environments, all observed individuals adaptively avoided a predator. Individuals from deforested reaches were more willing to enter well-lit habitat to avoid the predator. Despite documented declines of salamanders associated with forest removal, it appears that individuals are capable of making adaptive antipredator decisions in degraded habitats.
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Paterson, J. E., B. D. Steinberg, and J. D. Litzgus. "Generally specialized or especially general? Habitat selection by Snapping Turtles (Chelydra serpentina) in central Ontario." Canadian Journal of Zoology 90, no. 2 (February 2012): 139–49. http://dx.doi.org/10.1139/z11-118.
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Habitat selection is the disproportionate use of habitat compared with availability. Many studies have focused on specialists, but few have considered habitat selection in populations that are generalists, which can be composed of generalist individuals or individuals that specialize on different habitats. We tested habitat selection and individual specialization in a northern population of a supposed generalist, the Snapping Turtle ( Chelydra serpentina (L., 1758)), during the active season and winter using telemetry. Habitat selection was tested at two spatial scales by comparing random points to home ranges and turtle locations using Euclidean distances. Turtles selected home ranges from the habitats available in the population range. However, at the population level, all aquatic habitats were equally preferred, and the population behaved as a generalist owing to individuals specialized on different habitats. Over half of the individuals showed evidence of individual specialization on different habitat types. Turtles did not select habitat within home ranges during the active season, but overwintering turtles chose locations that were colder than haphazard stations in the same habitats, likely to reduce metabolic costs and the risk of acidosis. These findings have implications for the management of this species at risk and for understanding the evolution of resource generalization.
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Yan, Wen-Bo, Zhi-Gao Zeng, Hui-Sheng Gong, Xiang-Bo He, Xin-Yu Liu, Kai-Chuang Si, and Yan-Ling Song. "Habitat use and selection by takin in the Qinling Mountains, China." Wildlife Research 43, no. 8 (2016): 671. http://dx.doi.org/10.1071/wr16011.
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Context Understanding habitat use and selection by threatened ungulates is a crucial prerequisite to prioritise management areas and for developing effective conservation strategies. Aims The aim of our research was to determine the habitat use and selection of takins (Budorcas taxicolor) in the middle range of the Qinling Mountains, China. Methods The study was conducted from August 2013 to August 2015. Global positioning system (GPS) radio-tracking was used to monitor 10 collared takins to gain their location information. The Manly–Chesson selectivity index and Bonferroni-adjusted 95% confidence intervals were applied to determine which habitats were selected. Key results Habitat use and selection by takins showed obvious individual differences. At the landscape scale, all of the four most common habitat types were preferred by takins. However, all takins avoided artificially planted larch forest, and farmland and village. Available habitats within the home ranges also mostly included the four common habitat types. At the home-range scale, all individuals had significant habitat selectivity during the entire tracking period and each season. The habitat use and selection within the home range varied obviously with season and showed sexual differences to a certain extent. Conclusions The habitat selection by takins is scale-dependent. At the landscape scale, takins are most likely to occur at sites covered by forest. At both landscape and home-range scales, our results indicated that takins need more diverse forest habitats, but none of the four most common forest habitats is essential for survival of this species. Implications The present work has provided more insight into the habitat use and habitat selection of takins in mountainous forest landscapes. Many measures such as maintaining a diversity of forest habitats, avoiding habitat alteration by invasion of exotic plants, and increasing the area of available habitats by relocating the villages from within to outside of the reserve are recommended to conserve this large species.
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Park, Yonghwan, Chang-Jun Kim, Moon-Bo Choi, and Yuno Do. "A Comparative Study of Carabid Beetles in Green Spaces and Former Natural Habitats." Diversity 12, no. 12 (December 15, 2020): 479. http://dx.doi.org/10.3390/d12120479.
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Urban expansion threatens ecosystems through direct habitat conversion. To secure urban biodiversity and enhance ecosystem services, a common focus of planning and growth management efforts is to establish green spaces. This study aimed to understand the formation process of newly created green spaces after urban development. We investigated the carabid beetle assemblages in its current habitat in a new city and in its former habitats for assessing the loss of species diversity by urban development and to identify the initial status of species assemblages in the current urban habitats, including green spaces. The diversity and composition of the carabid beetle assemblages significantly changed in the new city. The former habitat loss by urban development leaves large numbers of carabid species to dramatically decline. Carabid assemblages in current habitats may show a critical response to habitat loss, although former habitats were converted to green spaces. Some carabid species were only present in current habitats, including the green space from former habitats. In addition, the current habitat, including green spaces and other habitats, have similar carabid assemblages. Our results indicated that the loss of former habitat has a much greater effect on species diversity persistence than changes in habitat configuration and the creation of green spaces. Consequently, most carabid beetles were already lost during development. Urban habitats in new cities, including green spaces, represent simple and homogeneous habitats, although the development was designed and planned to enhance biodiversity. The present design and planning practice for green spaces that destroyed all former habitats to prepare the ground of urban areas and thereby created urban habitats, including green space, may need to be changed to secure biodiversity. Designing and planning the green spaces should consider the species’ former habitats, for instance, creating a similar type of green space to agricultural land, forest, and wetland, and thereby the former habitat remains intact to enhance biodiversity and function.
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Rohmawati, Vivi Dwi, Husain Latuconsina, and Hasan Zayadi. "Fish Community in Different Mangrove Habitat in Banyuurip Ujung Pangkah – Gresik Regency." Agrikan: Jurnal Agribisnis Perikanan 14, no. 1 (April 6, 2021): 73–79. http://dx.doi.org/10.29239/j.agrikan.14.1.73-79.
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Mangroves are an important habitat for fish communities, as spawning, growing and foraging areas. This study aims to compare the species composition, presence frequency and structure of fish communities in different mangrove habitats. The research was conducted at Banyuurip Mangrove Center, Ujung Pangkah District, Gresik Regency, East Java, during July-August 2020. Determination of purposive sampling locations based on physical differences in mangrove habitats. Systematic sampling method was used to estimate the number of mangrove species using belt transects. Fish sample collection uses basic gill nets that are placed at high tide in each mangrove habitat. The results showed that the total number of individual mangrove vegetation was 505 from 12 species, the number of species and individual mangrove vegetation differed between habitats, and the highest was found in coastal mangrove habitats. The number of fish was found as many as 181 individuals from 11 species, 10 families and 5 orders. The number and composition of species, families and fish orders differ between mangrove habitats, with the highest number in coastal mangrove habitats. Mozambique tilapia (Oreochromis mossambicus) dominate the estuary mangrove habitat and giant trevally (Caranx sexfasciatus) dominate the coastal mangrove habitat. There are variations in the structure of fish communities between mangrove habitats, the dominance index value of the fish community in the estuary mangrove habitat is higher and in the medium category, while the coastal mangrove habitat is in the low category. On the other hand, the diversity index value of the fish community in the coastal mangrove habitat is in the high category and the estuary mangrove habitat is in the low category.
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Cao, An, and Xueyi Shi. "The Effects of Climate Change on Habitat Connectivity: A Case Study of the Brown-Eared Pheasant in China." Land 11, no. 6 (May 29, 2022): 806. http://dx.doi.org/10.3390/land11060806.
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Climate change has caused habitat fragmentation and reduced connectivity. The Fen River Basin in Shanxi Province, China is an important habitat for the central population of the brown-eared pheasant (BEP). The effects of climate change need to be considered in the conservation planning of BEP habitats. We used a species dispersion model to determine the BEP core habitat and graph theory to explore the connectivity of the BEP’s main habitats. The pinch point areas of BEP dissemination were determined by circuit theory. Least-cost pathways were used to identify the critical corridors for BEP dissemination. A gap analysis was conducted to estimate the efficiency of BEP conservation measures. Under the future climate scenarios, BEP habitats decreased by between 54.69% and 97.63%, and the connectivity of the main habitats was reduced by a similar magnitude. The BEP core habitat shifted to the southwestern region under the influence of climatic conditions. Currently, 90.84% of the species’ critical habitat remains unprotected. Due to climate change, the core habitat in the future was projected to differ from the current protected area. Enhancing the protection of the pinch point region may aid in the restoration of habitat connectivity.
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Ramalho, Emiliano Esterci, and William Ernest Magnusson. "USO DO HABITAT POR ONÇA-PINTADA (PANTHERA ONÇA) NO ENTORNO DE LAGOS DE VÁRZEA, RESERVA DE DESENVOLVIMENTO SUSTENTÁVEL MAMIRAUÁ, AM, BRASIL." Scientific Magazine UAKARI 4, no. 2 (February 15, 2009): 33–39. http://dx.doi.org/10.31420/uakari.v4i2.41.
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Understanding how a species moves between habitats available in its home range is key for interpreting spatial-temporal habitat selection patterns, foraging behavior, and predator-prey interactions. The use of habitat by the jaguar(Panthera onca) generally reflects the density and movement of its prey and not the availability of habitats. However, there is no information about how the species uses the habitats available in the Amazonian várzea. The objective of this study was to test if the jaguar uses the habitats available in the surroundings of várzea lakes, in proportion to their availability or if it shows preference for a specific habitat type. To achieve this objective we surveyed, on foot, the surroundings of 36 várzea lakes in the Mamirauá Sustainable Development Reserve, recording jaguar presence through observation of signs and identifying and quantifying the available habitats. Although we found signs of jaguar presence in all habitat types surveyed, the number of signs found in habitat type chavascal was greater than expected by its availability...
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Grzędzicka, Emilia. "Assessment of Habitat Selection by Invasive Plants and Conditions with the Best Performance of Invasiveness Traits." Diversity 15, no. 3 (February 25, 2023): 333. http://dx.doi.org/10.3390/d15030333.
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Habitat selection is one of the fundamental concepts in ecology and means that each organism should choose the habitat that will maximize its success. Invaders may be an underestimated object in research on habitat selection. Invasive plants experience enormous propagule pressure and bear the costs of spreading in disturbed anthropogenic habitats. It means that they do not necessarily achieve maximum invasiveness traits in such habitats, which they selected to colonize. This study aimed to assess habitats where invaders are likely to occur from the set of all available ones in the landscape and the habitats with the best performed traits of invaders. The research was conducted on 52 and 112 plots in 2019 and 2021, respectively, in South-Eastern Poland, and the invasive plants were Caucasian hogweeds Heracleum sp. In the first year, the circle plots had a 50 m radius and were to measure habitat areas and traits of hogweeds (height, number of individuals in the plot, cover, and number of flowering specimens). Detrimental correspondence analysis and linear mixed model investigated that hogweeds achieved the best performance reflected by traits in continuous habitats—meadows and forests. In the second year, the plots to measure habitats had a 100 m radius. The reference plots were far from the invasion exposure, and the paired control vs. Heracleum ones had the same habitats with the potential to be invaded. The generalized linear mixed model showed that the probability of the hogweeds occurrence was higher when the habitat was overgrowing with a simultaneous decrease in open areas and in the increasing ruderal area with a decrease in bushes. The impact of the invader’s habitat on the invasion performance depended on the purpose of habitat selection. When invaders spread and increased invasive extent or appeared in habitat edges, they did not reach the highest traits, the best performing in continuous habitats. The specificity of habitat selection of invaders is another aspect that distinguishes invasion science from classic ecology.
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Vasconcelos, Rita P., David B. Eggleston, Olivier Le Pape, and Ingrid Tulp. "Patterns and processes of habitat-specific demographic variability in exploited marine species." ICES Journal of Marine Science 71, no. 3 (September 7, 2013): 638–47. http://dx.doi.org/10.1093/icesjms/fst136.
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Abstract Population dynamics are governed by four demographic rates: births, deaths, immigration, and emigration. Variation in these rates and processes underlying such variation can be used to prioritize habitat conservation and restoration as well as to parameterize models that predict habitat-specific effects on population dynamics. The current understanding of patterns of habitat-specific demographic variability in exploited marine species, as well as processes underlying these patterns, was reviewed. We describe patterns of (i) habitat-specific density, followed by ontogenetic changes in habitat use, such as (ii) immigration (i.e. use as a settlement habitat) and (iii) emigration (i.e. use as a habitat for secondary dispersal to and from), and demographic rates such as (iv) growth, and (v) mortality. Despite the importance of coastal habitats for fish and invertebrate species and the vulnerability of these habitats to human impacts, there was ambiguous evidence on their role in driving of population dynamics. Roughly 63% of the studies were descriptive, 21% experimental, and 11% used a combination of descriptive and experimental approaches, whereas 5% used meta-analyses. Habitat-specific density was the most common pattern quantified, followed by growth and mortality, with relatively few examples of studies of habitat-specific larval settlement. There were many examples of the influence of coastal habitats on survival, growth, and movement, especially at young stages, and there was an emerging focus on the effects of habitat degradation on demographic rates. There needs to be an increased effort on quantifying habitat-specific demographic rates and integrating these to better predict the effects of coastal habitats on the dynamics of exploited marine populations.
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Thompson, Ian D. "The importance of superior-quality wildlife habitats." Forestry Chronicle 80, no. 1 (February 1, 2004): 75–81. http://dx.doi.org/10.5558/tfc80075-1.
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While animals may use many habitat types, relatively few are preferred and fewer yet are superior in quality (referring to individual fitness as the measure of quality). Historical reduction in habitat quality for some wildlife species has occurred such that we may now have limited reference to original superior-quality habitats. As time passes, managers may be unaware that superior habitats are slowly disappearing and that the slow but cumulative change is significant to a species at the population level. The perception of superior-quality habitat also changes with each successive generation of managers based on their experiences. This paper raises the concern that retrospective work may often be required to determine past forest habitats and associated animal populations to avoid the risk of falling into a trap of not recognizing ever-declining habitat quality through time and relegating animals to what is in fact much poorer quality habitat than those to which they are actually best adapted. Further, the relationship between relative abundance and habitat quality may often be uncertain owing to maladaptive habitat selection by animals, inappropriate survey timing or interannual population differences. While we have begun to appreciate aspects of habitat selection for many forest species, few data are yet available that relate selected habitats to fitness of individual animals. Hence, while we may have models to predict habitat use, considerable research remains to be done to be able to predict long-term sustainability of species in managed landscapes. Key words: habitat quality, forest management, sustainability, biodiversity
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Cappellari, Andree, and Lorenzo Marini. "Improving insect conservation across heterogeneous landscapes using species–habitat networks." PeerJ 9 (January 5, 2021): e10563. http://dx.doi.org/10.7717/peerj.10563.
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Background One of the biggest challenges in conservation is to manage multiple habitats for the effective conservation of multiple species, especially when the focal species are mobile and use multiple resources across heterogeneous protected areas. The application of ecological network tools and the analysis of the resulting species–habitat networks can help to describe such complex spatial associations and improve the conservation of species at the landscape scale. Methods To exemplify the application of species–habitat networks, we present a case study on butterflies inhabiting multiple grassland types across a heterogeneous protected area in North-East Italy. We sampled adult butterflies in 44 sites, each belonging to one of the five major habitat types in the protected area, that is, disturbed grasslands, continuous grasslands, evolved grasslands, hay meadows and wet meadows. First, we applied traditional diversity analyses to explore butterfly species richness and evenness. Second, we built and analyzed both the unipartite network, linking habitat patches via shared species, and the bipartite network, linking species to individual habitat patches. Aims (i) To describe the emerging properties (connectance, modularity, nestedness, and robustness) of the species–habitat network at the scale of the whole protected area, and (ii) to identify the key habitats patches for butterfly conservation across the protected area, that is, those supporting the highest number of species and those with unique species assemblages (e.g., hosting specialist species). Results The species–habitat network appeared to have a weak modular structure, meaning that the main habitat types tended to host different species assemblages. However, the habitats also shared a large proportion of species that were able to visit multiple habitats and use resources across the whole study area. Even butterfly species typically considered as habitat specialists were actually observed across multiple habitat patches, suggesting that protecting them only within their focal habitat might be ineffective. Our species–habitat network approach helped identifying both central habitat patches that were able to support the highest number of species, and habitat patches that supported rare specialist species.
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Seitz, Rochelle D. "Value of coastal habitats for exploited species: introduction to a theme set of articles." ICES Journal of Marine Science 71, no. 3 (March 2014): 636–37. http://dx.doi.org/10.1093/icesjms/fst180.
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Abstract Many exploited fish and invertebrate species use coastal habitats during one or more life-history stages as spawning, feeding, and nursery areas; yet, the value of these habitats has not been adequately characterized. As habitat availability can be a bottleneck for many populations, concerns about habitat effects on exploited species have been increasing. We have compiled nine articles presenting the state of knowledge and future research priorities regarding the importance of habitat for exploited species. Reviews from European habitats and several geographical locations throughout the United States demonstrate the influence of coastal habitats on survival, growth, and movement, especially during the early life-history stages, in a wide variety of species, spatial scales, and habitats. Moreover, many of these species contribute substantially to commercial landings, highlighting the importance of coastal habitats to population persistence and fishery yields. Management of fishery species can also be enhanced through modelling efforts incorporating habitat. Finally, there is a need for more effort in quantifying population demographics rates, creating comprehensive habitat maps, and developing better census techniques for complex hard bottom habitats; thus, future work is needed on the value of coastal habitats for exploited species.
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Phommavongsa, Sakkouna, Anh Nguyen Phan Hoang, and Manh Vu Quang. "Study on the natural habitats of the giant water bug Lethocerus indicus (Lepeletier et Seville, 1775) (Hemiptera : Belostomatidae) contributing to sustainable management of this rare water insect named in the Red Data Book of Vietnam." Journal of Science Natural Science 66, no. 4F (November 2021): 128–36. http://dx.doi.org/10.18173/2354-1059.2021-0075.
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The study was focused on the natural habitats and distribution of the giant water bug Lethocerus indicus in Lao PDR, with the aims to conserve and breed this rare water insect. The following conclusions were given: Adult giant water bugs were distributed in 5 main natural habitat types, including SC1. Habitat with flowing water such as rivers, streams and canals; SC2. Habitat type with standing or less flowing water such as ponds, lakes and lagoons; SC3. Habitat types such as water rice fields or aquatic plants; SC4. Habitat of standing water or puddles on the edge or inside the rice field; and SC5; and other Habitats include terrestrial, drifting with water, hiding in earthen caves near aquatic habitats. The number of adult giant water bugs decreased in the order of natural habitats studied, as follows SC3 >SC4 >SC2 >SC5 >SC1. The weter rice fields were the most suitable habitat for adult giant water bug. Research results showed that, there are similarities in the distribution of adult male and female in the studied natural habitats. The ratio of adult male to female giant water bug found in the above five studied natural habitats was 1.0 versus 2.3, respectively.
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Mysterud, Atle, Per Kristian Larsen, Rolf Anker Ims, and Eivind Østbye. "Habitat selection by roe deer and sheep: does habitat ranking reflect resource availability?" Canadian Journal of Zoology 77, no. 5 (October 1, 1999): 776–83. http://dx.doi.org/10.1139/z99-025.
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Habitat ranking is often assumed to reflect food availability, but habitat selection may involve trade-offs, for example, between selecting for food or cover. We tested whether the habitat selection of 27 radio-collared European roe deer (Capreolus capreolus) and 10 free-ranging domestic sheep (Ovis aries) on a forest range in southern Norway reflected resource availability. We predicted that ruminants of different feeding types would use habitats according to the main forage class, but that antipredator behavior might remove the correlation between habitat selection and food availability, thus making temporal and spatial scaling crucial. As predicted, habitat selection by sheep was highly correlated with grass availability on both the home-range and study-area scales. The habitat ranking of roe deer habitat selection did not correlate with the availability of herbs on either scale, but rather was correlated with the availability of canopy cover. We found a clear effect of temporal scale on habitat selection by roe deer. During summer, roe deer used forest habitats with more forage to a greater extent when they were active than when they were inactive, and tended to use habitats with greater availability of herbs at night. We conclude that scale-dependent trade-offs in habitat selection may cause inconsistent habitat rankings when pooled across temporal and spatial scales.
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Sundblad, Göran, Ulf Bergström, Alfred Sandström, and Peter Eklöv. "Nursery habitat availability limits adult stock sizes of predatory coastal fish." ICES Journal of Marine Science 71, no. 3 (April 18, 2013): 672–80. http://dx.doi.org/10.1093/icesjms/fst056.
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Abstract Habitat protection is a strategy often proposed in fisheries management to help maintain viable populations of exploited species. Yet, quantifying the importance of habitat availability for population sizes is difficult, as the precise distribution of essential habitats is poorly known. To quantify the contribution from coastal nursery habitats to exploited fish population sizes, we related adult density to the amount of nursery habitat available for 12 populations of the two dominant predatory fish species in a 40 000-km2 archipelago area of the Baltic Sea. Habitat distribution was mapped using three conceptually different techniques, Maxent, generalized additive models, and random forest, using spawning and 0-group point samples. Adult densities were estimated from gillnet surveys. Regressions demonstrated no evident effect from fishing, whereas habitat availability had a positive effect, explaining almost half of the variation in population sizes of both species. This result shows that a substantial proportion of the potential production of adult fish can be estimated by mapping essential nursery habitats distribution. Responses were non-linear, indicating that habitat protection has largest effects where there is little available habitat. By demonstrating the importance of habitat limitation of two exploited fish species, we provide quantitative support to the benefits of habitat protection for fisheries.
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Miaud, Claude, and Delfi Sanuy. "Terrestrial habitat preferences of the natterjack toad during and after the breeding season in a landscape of intensive agricultural activity." Amphibia-Reptilia 26, no. 3 (2005): 359–66. http://dx.doi.org/10.1163/156853805774408496.
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AbstractNineteen adult toads equipped with transmitters were followed during and after the breeding period (January to September) in order to estimate their home range area and habitat use in a landscape of cereal agriculture. Median home range area was 0.5 ha (range 0.1-11 ha) during the breeding season (January-April). Home range areas increase during the post-breeding season (April-September) e.g., median minimum concave polygon of 4.1 ha. No relation between home range and toads' body size was observed. Six habitat types were described in the studied area. The proportion of habitats used (i.e. proportion of the pooled positions of 11 toads during the post-breeding season in each habitat) was significantly different from the proportion of available habitats: while crops represented 85% of the available habitat, only 43% of the toads' positions were recorded in this type of habitat. A compositional analysis of habitat preference was performed. At both landscape and individual home range levels, the toads preferred the stone embankments and ditches above all, while the crops were the least preferred habitat. This study highlights the role of habitat linkage and marginal habitats for the persistence of amphibian populations in intensive agricultural and arid landscapes.
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Moravec, David, Vojtěch Barták, and Petra Šímová. "Finding Misclassified Natura 2000 Habitats by Applying Outlier Detection to Sentinel-1 and Sentinel-2 Data." Remote Sensing 15, no. 18 (September 7, 2023): 4409. http://dx.doi.org/10.3390/rs15184409.
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The monitoring of Natura 2000 habitats (Habitat Directive 92/43/EEC) is a key activity ensuring the sufficient protection of European biodiversity. Reporting on the status of Natura 2000 habitats is required every 6 years. Although field mapping is still an indispensable source of data on the status of Natura 2000 habitats, and very good field-based data exist in some countries, keeping the field-based habitat maps up to date can be an issue. Remote sensing techniques represent an excellent alternative. Here, we present a new method for detecting habitats that were likely misclassified during the field mapping or that have changed since then. The method identifies the possible habitat mapping errors as the so-called “attribute outliers”, i.e., outlying observations in the feature space of all relevant (spectral and other) characteristics of an individual habitat patch. We used the Czech Natura 2000 Habitat Layer as field-based habitat data. To prepare the feature space of habitat characteristics, we used a fusion of Sentinel-1 and Sentinel-2 satellite data along with a Digital Elevation Model. We compared outlier ratings using the robust Mahalanobis distance and Local Outlier Factor using three different thresholds (Tukey rule, histogram-based Scott’s rule, and 95% quantiles in χ2 distribution). The Mahalanobis distance thresholded by the 95% χ2 quantile achieved the best results, and, because of its high specificity, appeared as a promising tool for identifying erroneously mapped or changed habitats. The presented method can, therefore, be used as a guide to target field updates of Natura 2000 habitat maps or for other habitat/land cover mapping activities where the detection of misclassifications or changes is needed.
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Osuka, Kennedy, Marc Kochzius, Ann Vanreusel, David Obura, and Melita Samoilys. "Linkage between fish functional groups and coral reef benthic habitat composition in the Western Indian Ocean." Journal of the Marine Biological Association of the United Kingdom 98, no. 2 (October 10, 2016): 387–400. http://dx.doi.org/10.1017/s0025315416001399.
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Benthic habitat composition is a key factor that structures assemblages of coral reef fishes. However, natural and anthropogenic induced disturbances impact this relationship. This study investigates the link between benthic habitat composition and fish functional groups in four countries in the Western Indian Ocean (WIO). Benthic composition of 32 sites was quantified visually from percentage cover of hard and soft corals, rubble, turf, fleshy and crustose coralline algae. At each site, abundance of 12 coral-associated fish functional groups in 50 × 5 m transects was determined. Cluster analysis characterized reefs based on benthic cover and revealed five habitat types (A, B, C, D and E) typified by decreasing cover of hard corals, increasing cover of turf and/or fleshy algae and differences in benthic diversity. Habitat type A was present in all four countries. Other habitats types showed geographic affiliations: notably Comoros sites clustered in either habitats B or E, northern Madagascar had B, C and D type habitats, whereas sites in central Tanzania and northern Mozambique had habitats D and E. Fish functional groups showed significant linkages with some habitat types. The abundances of corallivores, invertivores, detritivores and grazers were higher in habitat B, whereas planktivores and small excavators showed lower abundances in the same habitat. These linkages between benthic habitat types and fish functional groups are important in informing priority reefs that require conservation and management planning.
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Tadesse, Solomon A., and Burt P. Kotler. "Habitat Choices of Nubian Ibex (Capra Nubiana) Evaluated with A habitat Suitability Modeling and Isodar Analysis." Israel Journal of Ecology and Evolution 56, no. 1 (May 6, 2010): 55–74. http://dx.doi.org/10.1560/ijee.56.1.55.
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The value of a habitat for a forager may be affected by habitat characteristics related to food availability, energetic costs of foraging, predation costs, and the foraging opportunities available in other habitats. Nubian ibex (Capra nubiana) are stout, sure-footed social wild goats that inhabit arid landscapes with steep terrain. We investigated their habitat selection behavior using indicators to (1) develop a habitat suitability index (HSI) model that would account for the variation in the activity densities of Nubian ibex across habitat types and seasons, (2) apply the isodar technique to look for density-dependent habitat selection behavior in Nubian ibex, and (3) investigate the proximate environmental factors that correlate to relative activity densities of Nubian ibex. We determined relative densities of the ibex by recording sightings of animals along standard walking transects. We incorporated the habitat variables that had greatest influence on the densities of Nubian ibex into habitat suitability index models for both spring and summer seasons.The HSI models revealed that Nubian ibex most preferred open cliff face habitat offering safety during the spring season, but their habitat preference shifted towards an area with watered gardens ("grave area habitat") during the summer season. Significant isodars were only obtained for the summer season comparisons between grave area versus cliff face, and between grave area versus plateau habitats. The slopes of the isodars suggest that the grave area habitat is 10.5 and 7.6 times more productive than the plateau and the cliff face habitats, respectively. Our results suggest that the relative abundances and habitat preferences of Nubian ibex varied with the seasonal availability of habitat resources, extent of predation risks, and human nuisance disturbances across the landscape. We recommend that wildlife managers dealing with the conservation and protection of the endangered Nubian ibex should focus on the various ecological and anthropogenic factors governing the habitat selection and preferences.
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Lithner, Stefan. "En jämförelse mellan fyra biotopers betydelse för fågelfaunan i mellersta Blekinge." Ornis Svecica 9, no. 4 (October 1, 1999): 201–16. http://dx.doi.org/10.34080/os.v9.22900.
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The birds were counted in four different habitats (coniferous forest, deciduous forest and two types of mixed farmland with much pasture and meadows, one near the coast and the other one upland) during winter (November 1997–March 1998) and spring (late April through June 1998) in the province of Blekinge, southern Sweden. One point count route with 12 points was established in each habitat. Five complete counts were made in each season with a five minutes count at each point. All birds seen or heard were counted, but in this study I included only birds that actually used (keeping a territory, feeding, resting) in the specific habitat of each route. The coniferous habitat was poorer than the deciduous one, especially in winter. Six of the 12 points in the coniferous habitat had no deciduous trees and it was mainly these monocultures that were poor. The other points with some deciduous trees compared well with the deciduous habitat. The two pasture habitats were much richer than the forest habitats in winter. In spring there was only a small difference between the forest habitats and the upland pasture habitat, whereas the coastal pasture habitat was much richer, mainly because of a few coastal species. Vicinity to lakes, watercourses and marshes was a key factor contributing to high species diversity in both farmland habitats.
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Kiatoko, Nkoba, Suresh Kumar Raina, and Frank van Langevelde. "Impact of habitat degradation on species diversity and nest abundance of five African stingless bee species in a tropical rainforest of Kenya." International Journal of Tropical Insect Science 37, no. 03 (August 17, 2017): 189–97. http://dx.doi.org/10.1017/s174275841700011x.
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AbstractNatural habitat degradation often involves the reduction or disappearance of bee species. In Africa, stingless bees are hunted for honey, which is used as food, for medicinal purposes, and for traditional rituals. Severe habitat degradation due to human settlement is hypothesized to have a negative impact on the species diversity of the African stingless bee species. In this paper, we assess the impact of habitat degradation on the diversity of five stingless bee species across different habitats in the tropical rainforest of Kenya (indigenous forest, mixed indigenous forest) and its neighbouring landscape (grassland, village) in western Kenya. The species fauna, nest occurrence, and species diversity of the stingless bee species varied across the different habitats. The number of nesting habitats of the meliponine species varied between habitats in the tropical rainforest.Meliponula ferruginea(reddish brown) nested in five habitats, whileMeliponula bocandeiandMeliponula ferruginea(black) nested only in two habitat types. The species richness decreased within the different types of habitats and the indigenous and mixed indigenous forest contained more species than other habitats. The fauna composition in both homesteads was exclusively similar, while the indigenous and mixed indigenous forests were mostly similar. Similarity in habitat preferences for nesting was revealed betweenM. bocandeivsPlebeina hildebrandtiandM. ferruginea(reddish brown) vsHypotrigona gribodoi. The natural native indigenous forest had the most diverse community compared to the degraded habitats. There are taxon-specific responses to habitat change; and in our study, there is clear value in conserving the native indigenous forest.
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Oliveira de Menezes, Andressa Silvana, and Fernando Augusto Schmidt. "Mechanisms of species coexistence and functional diversity of ant assemblages in forest and pasture habitats in southwestern Brazilian Amazon." Sociobiology 67, no. 1 (April 18, 2020): 33. http://dx.doi.org/10.13102/sociobiology.v67i1.4552.
Full textAbstract:
In this study, we investigated the mechanisms behind species coexistence and the relationships between functional diversity and species richness in ant assemblages in both forest and pasture habitats in the southwestern Brazilian Amazon. We addressed the specific question: What is the primary mechanism for species coexistence in forest and pasture habitats? According to the identified mechanism in each habitat, we had the following alternative expectations: (i) niche partitioning – we expected to observe a linear positive relationship between functional diversity and species richness, indicating a complementary relationship; or (ii) niche filtering – a positive constant asymptotic relation between functional diversity and species richness, indicating a functional redundancy relationship. In total, we sampled 91 ant species, 82 species in a forest habitat and 16, in a pasture habitat. In the forest habitat we identified niche filtering as the structuring mechanism of the ant assemblage, but we were unable to identify a clear mechanism in the pasture habitat. Although the relationship between functional diversity and species richness was positive in both habitats, the relationship was weaker in the forest habitat, indicating a greater functional redundancy among the ant species in this habitat. Our results reinforce the divergence of species coexistence mechanisms and ant assemblage structures in both natural and human-modified habitats in the Southwestern Brazilian Amazon.
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Fort, Kevin T., and Ken A. Otter. "Effects of Habitat Disturbance on Reproduction in Black-Capped Chickadees (Poecile Atricapillus) in Northern British Columbia." Auk 121, no. 4 (October 1, 2004): 1070–80. http://dx.doi.org/10.1093/auk/121.4.1070.
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Abstract Avian species that persist in breeding in disturbed habitats are often thought to be less affected by disturbance than habitat specialists lost following disturbances, yet there is growing evidence that human-altered environments may negatively affect reproductive behavior and nest success of those generalists as well. We compared nest success of Blackcapped Chickadees (Poecile atricapillus) in two adjacent habitats: a mature mixed-wood forest (undisturbed) and a forest regenerating after logging (disturbed). Despite similar breeding densities, proportion of nests that successfully fledged young was lower in the disturbed habitat than in the undisturbed habitat. Abandonment was the most common cause of nest failure. A within-habitat comparison of the social rank of birds revealed that low-ranking birds had lower nest success than high-ranking birds in the disturbed, but not in the undisturbed, habitat. Clutch size and brood size of nests that progressed to the point of hatch did not differ significantly between habitats. Average total number of fledglings produced per pair, though not significantly different, was suggestively lower in the disturbed habitat. Across habitats, nests situated in snags with lower amounts of internal decay were more successful. Successful nests were also located in sites with higher canopy height, low understory density below 1 m, and higher understory density between 2 and 3 m—all attributes generally associated with undisturbed, mature forests in the region. Our results provide evidence that disturbed habitats may represent poor-quality habitat for this forest generalist, and that habitat quality differentially affects individuals, depending on their dominance rank.
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Quayle, James F., and G. Peter Kershaw. "Use of summer habitat by caribou on the north slope of a mountain near the Macmillan Pass, N.W.T." Rangifer 16, no. 4 (January 1, 1996): 311. http://dx.doi.org/10.7557/2.16.4.1271.
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Habitat use by woodland caribou was investigated by counting pellet-groups, sampling phytomass, and evaluating topography in nine habitat-types on the north slope of an unnamed mountain near Macmillan Pass, N.W.T. Caribou pellets were most abundant in high elevation habitat-types, and pellet density was greatest in an alpine Lichen-Grass habitat-type with a slope of <1°. The high density of pellets in alpine areas may have resulted from of the use of cool, windy, alpine habitats by caribou seeking relief from insect harassment. There were no apparent relationships between pellet abundance, and phytomass of mosses, lichens, or graminoids, possibly as a result of caribou feeding and defecating in different habitats. The occurrence of pellets with a coalesced morphology in the barren Lichen-Grass habitat-type provided indirect evidence in support of a feeding cycle, whereby caribou visit lush habitats to feed, and return to open, alpine habitats to rest and ruminate.
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I Made Budiarsa, Fatmah Dhafir, and Manap Trianto. "Morphometrical Variations of Tetragonula laeviceps in Different Habitats in Central Sulawesi Province." BIOEDUSCIENCE 6, no. 2 (August 31, 2022): 165–70. http://dx.doi.org/10.22236/j.bes/625062.
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Background: Habitat is a place for living things to grow and develop. Differences in habitat in an area can affect the size of an organism. This study aims to determine the morphometric variations of Tetragonula laeviceps found in urban and forest habitats in Central Sulawesi Province. Methods: This research was conducted with roaming technique. Morphometric characters observed were 35 characters of stingless bee and analyzed using Microsoft Excel software. Results: The results of this study indicated that the morphometric size variation of T. laeviceps found in forest habitats (3.58 mm) is greater than that of wild bee in urban habitats (3.05 mm). Conclusions: Different habitat characteristics can affect the morphometry variations of the bee, especially in T. laeviceps species. The bee's morphometry body size is greater than in the forest habitat, because in that habitat there are environmental temperatures and types of plant sources of nectar which are more supportive for bee life compared to urban habitats.
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Jayawardana, J. M. C. K., Martin Westbrooke, Michael Wilson, and Cameron Hurst. "Macroinvertebrate communities in willow (Salix spp.) and reed beds (Phragmites australis) in central Victorian streams in Australia." Marine and Freshwater Research 57, no. 4 (2006): 429. http://dx.doi.org/10.1071/mf05139.
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Exotic willows (Salix spp.) are widespread riparian tree species of rivers in temperate Australia and New Zealand. Despite being considered as a weed of national significance, little is known about the habitat value of willows and the impact on aquatic biota of vegetation change following willow management programmes. Macroinvertebrate fauna in root habitats of willows and Phragmites australis habitats were examined in three central Victorian rivers to understand the effect of such littoral habitat changes on macroinvertebrates. Data were analysed using Partially Nested Factorial ANOVA with season, river and habitat as main effects. Habitat structure had a significant effect (P < 0.05) on macroinvertebrate community assemblage. However, effect of habitat was not consistent among seasons. The greatest community differences among habitats were observed during winter and least separation during autumn. Taxa responsible for community differences among habitats were also identified. Species richness and abundance did not show consistent variation among habitats over different rivers or seasons. This study provided some indication of the macroinvertebrate community changes that would take place in situations where riparian vegetation changes takes place from willows to P. australis.
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Garnick, S., J. Di Stefano, M. A. Elgar, and G. Coulson. "Do body size, diet type or residence time explain habitat use in a vertebrate herbivore community?" Australian Journal of Zoology 64, no. 2 (2016): 91. http://dx.doi.org/10.1071/zo15061.
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Many theories attempt to explain patterns of community organisation among large herbivores. We explored the role of body size, diet type and residence time on habitat use in a community comprising four metatherians (western grey kangaroo, Macropus fuliginosus; eastern grey kangaroo, M. giganteus; red-necked wallaby, Notamacropus rufogriseus; swamp wallaby, Wallabia bicolor) and two eutherians (red deer, Cervus elaphus; European rabbit, Oryctolagus cuniculus) in south-eastern Australia. We used camera traps to estimate habitat occupancy, quantified habitat specialisation using relative entropy, and ran regressions using percentage grass consumed, log(mass) and log(time at site) as predictor variables and relative entropy as the response. If body size influenced habitat use, we predicted smaller species would occupy fewer habitats. If diet type influenced habitat use, we predicted intermediate feeders would use more habitats. If the time that a species had been present at a site predicted community organisation, newer species would use more habitats. None of these theories explained habitat use in our community. Red deer used a narrower range of habitats than expected, perhaps due to the poor suitability of habitats available in the Grampians. While interactions between our hypotheses are likely to be important, the body size model deserves further attention in this community.
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Liu, Yuan, Xianglin Ji, and Lizhi Zhou. "Assessment of Waterbird Habitat Importance and Identification of Conservation Gaps in Anhui Province." Animals 14, no. 7 (March 25, 2024): 1004. http://dx.doi.org/10.3390/ani14071004.
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Wetlands are among the most important habitats of highly wetland-dependent waterbirds but are subject to ongoing habitat loss and degradation owing to intensified anthropogenic activities. The scarcity of human and natural resources makes effective habitat protection an important concern. Here, we aimed to investigate waterbird habitat protection methods for Anhui Province, China, a critical stopover and wintering area on the East Asian-Australasian Flyway that features rich wetland resources subject to significant habitat loss and degradation. We evaluated the status and importance of 306 wintering waterbird habitats and identified the key environmental influences and current protection gaps using the entropy weights method and generalized additive modeling. We found 73 important habitats for waterbirds in Anhui Province, which were classified into levels of importance (descending from I to V) according to the natural discontinuity method. Level I and Level II habitats were mainly located in the Yangtze River floodplain and Level IV habitats in the Huaihe River floodplain. The gap analysis showed that 42 important waterbird habitats had protection gaps, accounting for 57.53% of the total area. Waterbird habitat importance was significantly correlated with elevation, normalized vegetation index, lake area, and lake circumference but not with distance from roads or population density. The results of this study provide scientific information for waterbird habitat conservation planning, which is crucial for maintaining wetland ecosystem functions.