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opencc-zeroAug 2020View details →

Species richness and abundance of vascular epiphytes along an elevation gradient

Because of the difficulty in sampling and the logistics of identifying canopy-dwelling plants, the number of inventories quantifying tropical epiphytes is limited. This has resulted in a substantial gap in knowledge, even though forest canopies contain significant biodiversity and forest biomass. In the case of Volcán Maderas, multiple ecological and taxonomic research initiatives have been conducted. However, for vascular epiphytes, georeferenced specific spatial descriptions were lacking and a standardized effort for documenting species richness was non-existent. We provide a detailed qualitative and quantitative assessment of the vascular epiphyte flora and its spatial distribution. These data shed light on important plant assemblages across elevational gradients that can be used for monitoring and understanding adaptive strategies to drought conditions.

opencc-by-4.0Feb 2016View details →

Figure 3 in Abundance, species richness and diversity of the orb-weaving spider families Araneidae, Nephilidae and Tetragnathidae in natural habitats in Trinidad, West Indies

Figure 3. The absence of a relationship between mean niche breadth of species and observed species richness at a locality, for 46 localities with natural habitats; r = −0.12, P = 0.42.

opencc-by-4.0Feb 2016View details →

Figure 2 in Abundance, species richness and diversity of the orb-weaving spider families Araneidae, Nephilidae and Tetragnathidae in natural habitats in Trinidad, West Indies

Figure 2. The weak relationship between observed species richness and abundance of individuals in the sample, for 46 localities with natural habitats; r = 0.45, P = 0.002.

opencc-zeroNov 2020View details →

Data from: Altitude shapes the environmental drivers of large-scale variation in abundance of a widespread mammal species

Habitat quality and heterogeneity directly influence the distribution and abundance of organisms at different spatial scales. Determining the main environmental factors driving the variation in species abundance is crucial to understand the underlying ecological processes and this is especially important for widely distributed species living in contrasting environments. However, the responses to environmental variation are usually described at relatively small spatial scales. Here, we studied the variation in abundance of a widely distributed mustelid, the European badger (Meles meles), across France. We used (1) direct detections of 9,439 dead and living badgers, from 2006 to 2009, to estimate badger relative abundance in 703 small agricultural regions of metropolitan France and (2) a Bayesian modelling approach to identify the main environmental determinants influencing badger abundance. Despite a continuous distribution of badger in France, we found large variation in badger abundance between regions, explained by environmental factors. Among a set of 13 environmental variables, we demonstrated that badger abundance in lowlands (< 400 m a.s.l.) was mostly driven by biotic factors such as potential food resources (earthworm abundance and fruits crops) and forest fragmentation. Conversely, in mountainous areas, abiotic factors (i.e. soil texture and climate) drove the variation in badger relative abundance. These results underline the importance of mapping the abundance of wildlife species based on environmental suitability, and highlight the complexity of drivers influencing species abundance at such large spatial scales. Altitude shaped the environmental drivers (biotic vs. abiotic) that most influenced relative abundance of a widespread species. In the case of badger, such abundance maps are crucial to identify critical areas for species management as this mustelid is a main wild vector of bovine tuberculosis in several countries.

opencc-zeroDec 2020View details →

Species abundance along the railway of Kashmir Himalaya

1. The significant portion of global terrestrial biodiversity harbored in mountains is under increasing threat from a variety of anthropogenic impacts. Protecting fragile mountain ecosystems requires understanding how these human disturbances affect biodiversity. As roads and railways are extended further into mountain ecosystems, understanding the long-term impacts of this infrastructure on community composition and diversity gains urgency. 2. We used railway corridors constructed across the mountainous landscapes of the Kashmir Himalaya from 1994-2013 to study the effects of anthropogenic disturbance on species' distributions and community dynamics. In 2014 and 2017, we collected vegetation data along 31 T-shaped transects laid perpendicular to the railway line, adopting the MIREN (Mountain Invasion Research Network) road survey methodology. 3. Plant communities shifted significantly from 2014 to 2017, potentially as a result of ongoing species' redistribution after railway construction, mostly driven by declines in both native and non-native species richness, and increasing abundance of a few non-native species, especially in areas away from the railway track. 4. These patterns indicate an advancing succession, where initial – rare – pioneering species are replaced by increasingly dominant and often non-native competitors, and potentially suggest a trend towards delayed local extinctions after the disturbance event. Native and non-native species richness were negatively correlated with elevation, but that relationship diminished over time, with the abundance of non-natives significantly increasing at high elevations. 5. Synthesis and applications: Transport corridors seem to facilitate the spread of non-native species to higher elevations, which has serious implications in light of the warming mountain tops. Our results indicate that plant communities next to railways do not reach equilibrium quickly after disturbance. More than 10 years after railway establishment succession continued, and signs pointed in the direction of a landscape increasingly dominated by non-native species. Our study indicates that the single disturbance event associated with construction of a railway in the Himalayas had large and long-lasting effects on plant communities at and around this transport corridor, and suggests the need for a long-term region-wide coordinated monitoring and management program.

opencc-zeroDec 2014View details →

Data from: A hierarchical distance sampling model to estimate abundance and covariate associations of species and communities

Distance sampling is a common survey method in wildlife studies, because it allows accounting for imperfect detection. The framework has been extended to hierarchical distance sampling (HDS), which accommodates the modelling of abundance as a function of covariates, but rare and elusive species may not yield enough observations to fit such a model. We integrate HDS into a community modelling framework that accommodates multi-species spatially replicated distance sampling data. The model allows species-specific parameters, but these come from a common underlying distribution. This form of information sharing enables estimation of parameters for species with sparse data sets that would otherwise be discarded from analysis. We evaluate the performance of the model under varying community sizes with different species-specific abundances through a simulation study. We further fit the model to a seabird data set obtained from shipboard distance sampling surveys off the East Coast of the USA. Comparing communities comprised of 5, 15 or 30 species, bias of all community-level parameters and some species-level parameters decreased with increasing community size, while precision increased. Most species-level parameters were less biased for more abundant species. For larger communities, the community model increased precision in abundance estimates of rarely observed species when compared to single-species models. For the seabird application, we found a strong negative association of community and species abundance with distance to shore. Water temperature and prey density had weak effects on seabird abundance. Patterns in overall abundance were consistent with known seabird ecology. The community distance sampling model can be expanded to account for imperfect availability, imperfect species identification or other missing individual covariates. The model allowed us to make inference about ecology of species communities, including rarely observed species, which is particularly important in conservation and management. The approach holds great potential to improve inference on species communities that can be surveyed with distance sampling.

opencc-zeroSep 2019View details →

Data from: Bird species diversity in Altai riparian landscapes: wood cover plays a key role for avian abundance

Aims: We aim to understand bird richness and variation in species composition (beta diversity) along a 630 km riparian landscape in the Altai Mountains of China, and to test whether vegetation cover is the main explanation of species diversity. Methods: We selected nine regions along a gradient of natural vegetation change. Bird surveys and environmental measurements were conducted at 10 points in each of the nine regions. We collected environmental land cover variables such as wood cover (area proportion of trees and shrubs with saplings in habitats; here trees are woody plant with a single trunk and higher than 3m, shrubs and saplings are distinguished from trees by their multiple trunks and shorter height) and tree cover, and two climate factors which were Annual Mean Temperature (AMT) and Annual Precipitation (AP). We used Liner Regression Models to explore the correlation between bird species richness and environmental variables. We used Sørensen's dissimilarity index to measure birds' beta diversity, and quantified the contribution of environmental variables to this pattern using a Canonical Correspondence Analysis (CCA). Results: Wood cover was the strongest predictor of overall, insectivore and omnivore bird richness. Regions with wood cover contained more bird species. Beta diversity was overall high in the studied regions, and turnover components occupied a major part of beta diversity. Wood cover and AP were significant predictors of bird species composition explaining 33.24% of bird beta diversity together. Conclusions: Wood vegetation including trees, shrubs and saplings, rather than only trees, contains high bird richness. High beta diversity suggests that expansion of the existing nature reserves is needed in the riparian landscapes to capture the variation in bird species composition. Thus all wood cover in the overall riparian landscapes of Altai Mountains should be protected from farming and grazing to improve bird conservation outcomes.

opencc-zeroDec 2023View details →

Diversity and factors shaping bird species abundance in a hilly region of Makawanpur district, Nepal

Birds play a major role in seed dispersal through pollination, nutrient cycle, and pest control. Understanding contributing factors (both ecological and anthropogenic), and their influence on the diversity of birds is crucial to sustain ecosystem balance and prosperity. We investigated the diversity and associated factors of bird species in a hilly region of Makawanpur district, Nepal. The field survey was conducted throughout the winter season (December-February 2021) using the point count method (radius=30 m). Within the study area, we established 22 sampling plots between the elevations of 431 m above sea level to 2503 m asl. We used generalized linear model to investigate the role of different factors in shaping the species richness pattern. A total of 1860 independent observations of 172 bird species were made during the study where the majority of the species were common and belonged to order Passeriformes. We observed a decrease in bird diversity with increase in elevation. The quantity of invasive plant species (IAPS) cover, disturbance and the slope of the area substantially impacted the diversity of bird species. Research on diversified bird species and their associations with many factors require a more detailed and long-term survey to investigate more species as well as other patterns and processes throughout the elevational gradient.

opencc-by-4.0Aug 2024View details →

Recent abundance changes at species' range limits in the North and Central American avifaunas

Data and code for submitted manuscript

opencc-by-4.0Oct 2023View details →

Few species, higher abundance or many species and lower abundance of birds of prey: effects of land use changes at different spatial scales

Open the record for dataset details and reuse information.

opencc-by-4.0May 2019View details →

Figure 1 in Decapod abundance and species richness in the bycatch of Xiphopenaeus kroyeri (Heller, 1862) fishery, Santa Catarina, southern Brazil

Figure 1. Studied region. The adjacent area from the Babitonga Bay, northern litoral of the Santa Catarina State, highlighting the sampled depths (source: Grabowski et al., 2014).

opencc-by-4.0May 2012View details →

Fig. 1 in Observations On Species Abundance Distribution In Fly Collections

Fig. 1. Frequency polygons of 2-moving averaged abundance frequencies with the serial number of the average on the horizontal axis. For example, in the case of collection 2003 the first average is

opencc-by-4.0Oct 2021View details →

Extreme droughts in oligotrophic mountain grasslands cause substantial species abundance changes and amplify community filtering

Questions Mountain grasslands can be strongly affected by extreme droughts such as those related to climate change. What are the impacts of extreme droughts on community composition, diversity, Ellenberg indicator scores and species groups in oligotrophic montane Nardus grasslands, and what are the associated mechanisms of vegetation change? Location Rhön Mountains, Germany Methods In three consecutive years, we investigated the effects of yearly droughts (April-August) in an experimental setup with rainout shelters. Due to the coincidence of ambient extreme dry conditions in those years and our artificial rainfall reduction, we evaluated the contribution to community change of ambient drought conditions and the treatments. We analysed community composition changes by applying redundancy analysis to species differences in comparison with the pre-treatment year, and used mixed-effects models to test for changes in community-weighted means of Ellenberg indicator scores, sociological, and functional groups. Results We found significant changes in species abundances and community structures in response to drought. Evenness increased, but species richness remained rather stable over time. Ellenberg indicator scores for temperature and nitrogen increased, while the score for moisture decreased. Simultaneously, dominant species declined and subdominants increased. Changes occurred with a time lag and were largely driven by the high ambient drought level and less by the artificial treatments. Conclusions Our results show that drought-related community composition changes in Nardus grasslands occur across community structures, characteristic species, and species groups. The post-drought recovery of the community is shaped by community filters, which particularly allow subdominants to take advantage of newly available niches in the matrix, even if they lack strong drought tolerance. Our findings indicate a certain resilience of the community to climate-change-related droughts, which suggests that the observed changes should not lead to an accelerated short-term decline of these grasslands, but that this cannot be excluded in the long term.

opencc-zeroJan 2022View details →

Abundance data of anuran species in forest fragments

Understanding the effects of random versus niche-based processes on biodiversity patterns is a central theme in ecology, and an important tool for predicting effects of habitat loss and fragmentation on biodiversity. We investigated the predictive power of random processes to explain species richness and species dissimilarity of amphibian assemblages in a fragmented tropical landscape of the Atlantic Forest of South America. We analyzed a large database of amphibian abundance and occupancy, sampled in 21 forest fragments ranging in size from 1.9 to 619 ha. We compared observed species richness and species dissimilarity with the outcomes of two null (random placement) models: 1- the traditional Coleman's area-based model and 2 – an abundance-based model (based on the number of individuals observed in each fragment). We applied these models for all species combined, and separately for forest‐dependent and habitat-generalist species. The abundance-based model fitted the observed species richness data better than the area-based model for all species, forest-dependent species, and generalist species. The area-based and the abundance-based models were also able to significantly explain species dissimilarity for all species and for generalists, but not for forest-dependent species. The traditional area-based model assigned too many individuals to large fragments, thus failing to accurately explain species richness within patches across the landscape. Although niche-based processes may be important to structuring the regional pool of species in fragmented landscapes, our results suggest that part of the variation in species richness and species dissimilarity can be successfully explained by random placement models, especially for generalist species. Evaluating which factors cause variation in the number of individuals among patches should be a focus in future studies aiming to understand biodiversity patterns in fragmented landscapes.

opencc-zeroFeb 2022View details →

Supplementary material 1 from: DeRoy EM, Crookes S, Matheson K, Scott R, McKenzie CH, Alexander ME, Dick JTA, MacIsaac HJ (2022) Predatory ability and abundance forecast the ecological impacts of two aquatic invasive species. NeoBiota 71: 91-112. https://doi.org/10.3897/neobiota.71.75711

Table S1

opencc-zeroMar 2022View details →

Introduced honey bees increase host plant abundance but decrease native bumble bee species richness and abundance

Long-term variation in the population density of introduced honey bees (Apis mellifera) has been shown to be associated with variations in floral traits in alpine lotus (Saussurea nigrescens). However, it remains to be determined whether a high density of honey bees affects the abundance of nectariferous plants and the species richness and abundance of native bumble bees. We predicted that a high density of introduced honey bees lasting three decades would decrease the species richness and abundance of native bumble bees but increase the abundance of honeybee host plant species. Here, the field experiments were conducted to examine the diversity of nectariferous plants and native bumble bees along the typical gradients of honey bee density (high density of honey bee at close apiary and low density of honey bee at distant of apiary). We investigated nectariferous plant abundance, floral and seed traits, bumble bee species richness and abundance at sites with either a high or low honey bee density in an alpine meadow. Our results demonstrated that an increased population of introduced honey bees was associated with increased host plant abundance and flower/capitula number per plant but decreased nectar volume per flower, seed mass, species richness and abundance of native bumble bees. The bumble bee visitation rate was positively correlated with nectar volume per flower at sites close to and far from apiaries. The honey bee visitation rate was positively correlated with flower/capitula number per plant at sites close to apiaries and nectar volume per flower at sites far from apiaries. Seed mass was negatively correlated with nectariferous plant abundance. Our findings showed that introduced honey bees decreased the species richness and abundance of native bumble bees, attributed to evolutionary decrease nectar resources among honey bee host plant species, but increased the abundance of nectariferous plants, attributed to the production of many small seeds by plants. This suggests that long-term high-density beekeeping affects the biodiversity of honey bee host plants and native bumble bees. Our results provide new insights into the mechanisms of maintaining the biodiversity of nectariferous plants and native bumble bees.

Figure 8 from: Landschoff J, Lemaitre R (2017) Differentiation of three common deep-water hermit crabs (Crustacea, Decapoda, Anomura, Parapaguridae) from the South African demersal abundance surveys, including the description of a new species of Paragiopagurus Lemaitre, 1996. ZooKeys 676: 21-45. https://doi.org/10.3897/zookeys.676.12987

Figure 8 - South African distribution of three parapagurid species based on specimens found during DAFF demersal research surveys.

Figure 6 from: Landschoff J, Lemaitre R (2017) Differentiation of three common deep-water hermit crabs (Crustacea, Decapoda, Anomura, Parapaguridae) from the South African demersal abundance surveys, including the description of a new species of Paragiopagurus Lemaitre, 1996. ZooKeys 676: 21-45. https://doi.org/10.3897/zookeys.676.12987

Figure 6 - Colouration (in life or fresh). Paragiopagurus atkinsonae sp. n., South Africa, West Coast: A male holotype 7.0 mm, WCDSS2016 (USNM 1292083) B ovig. female 6.4 mm, WCDSS2016 (SAMC MB-A066816) C ovig. female 6.8 mm, WCDSS2016 (SAMC MB-A066809), shield and cephalic appendages, dorsal view.

Figure 5 from: Landschoff J, Lemaitre R (2017) Differentiation of three common deep-water hermit crabs (Crustacea, Decapoda, Anomura, Parapaguridae) from the South African demersal abundance surveys, including the description of a new species of Paragiopagurus Lemaitre, 1996. ZooKeys 676: 21-45. https://doi.org/10.3897/zookeys.676.12987

Figure 5 - Paragiopagurus atkinsonae sp. n., South Africa, West Coast, male holotype 7.0 mm, WCDSS2016 (USNM 1292083). A pereopod 2, lateral view B dactyl of same, mesial view C pereopod 3, lateral view D dactyl of same mesial view E sternite XII and basal portion of coxae of pereopods 3, ventral view F propodus and dactyl of pereopod 4, lateral view G propodus and dactyl of pereopod 5, lateral view.

Figure 7 from: Landschoff J, Lemaitre R (2017) Differentiation of three common deep-water hermit crabs (Crustacea, Decapoda, Anomura, Parapaguridae) from the South African demersal abundance surveys, including the description of a new species of Paragiopagurus Lemaitre, 1996. ZooKeys 676: 21-45. https://doi.org/10.3897/zookeys.676.12987

Figure 7 - A, B Sympagurus dimorphus (Studer, 1883), South Coast C, D Parapagurus bouvieri Stebbing, 1910, West Coast (C), South Coast (D). A male 11.2 mm SCDSA 2016 (SAMC MB-A066492) B ovig. female 9.4 mm SCDSA 2016 (SAMC MB-A066491) C male 12.2 mm, WCDSS (SAMC MB-A066432) D male 10.6 mm, SCDSS2016 (SAMC MB-A066794), front view of live specimen in aquarium, using zoanthid (Epizoanthus sp.) carcinoecia.