scholarly journals The winter distribution of the Spoon-billed Sandpiper Calidris pygmaeus

2016 ◽  
Vol 26 (4) ◽  
pp. 476-489 ◽  
Author(s):  
CHRISTOPH ZÖCKLER ◽  
ALISON E. BERESFORD ◽  
GILLIAN BUNTING ◽  
SAYAM U. CHOWDHURY ◽  
NIGEL A. CLARK ◽  
...  
Keyword(s):  
Breeding Population ◽  
Wide Distribution ◽  
Present Species ◽  
Suitable Habitat ◽  
Distribution Models ◽  
Entropy Model ◽  
Potential Habitat ◽  
Winter Distribution ◽  
Wintering Areas ◽  
Key Sites

SummaryDeclines in populations of the Critically Endangered Spoon-billed Sandpiper Calidris pygmaeus have been rapid, with the breeding population now perhaps numbering fewer than 120 pairs. The reasons for this decline remain unresolved. Whilst there is evidence that hunting in wintering areas is an important factor, loss of suitable habitat on passage and wintering areas is also of concern. While some key sites for the species are already documented, many of their wintering locations are described here for the first time. Their wintering range primarily stretches from Bangladesh to China. Comprehensive surveys of potential Spoon-billed Sandpiper wintering sites from 2005 to 2013 showed a wide distribution with three key concentrations in Myanmar and Bangladesh, but also regular sites in China, Vietnam and Thailand. The identification of all important non-breeding sites remains of high priority for the conservation of the species. Here, we present the results of field surveys of wintering Spoon-billed Sandpipers that took place in six countries between 2005 and 2013 and present species distribution models which map the potential wintering areas. These include known and currently unrecognised wintering locations. Our maximum entropy model did not identify any new extensive candidate areas within the winter distribution, suggesting that most key sites are already known, but it did identify small sites on the coast of eastern Bangladesh, western Myanmar, and the Guangxi and Guangdong regions of China that may merit further investigation. As no extensive areas of new potential habitat were identified, we suggest that the priorities for the conservation of this species are habitat protection in important wintering and passage areas and reducing hunting pressure on birds at these sites.

scholarly journals Scaling up ideals to freedom: are densities of red knots across western Europe consistent with ideal free distribution?

2011 ◽  
Vol 278 (1719) ◽  
pp. 2728-2736 ◽  
Author(s):  
Gwenaël Quaintenne ◽  
Jan A. van Gils ◽  
Pierrick Bocher ◽  
Anne Dekinga ◽  
Theunis Piersma
Keyword(s):  
Uniform Distribution ◽  
Western Europe ◽  
Ideal Free Distribution ◽  
Scale Up ◽  
Suitable Habitat ◽  
Distribution Models ◽  
Free Distribution ◽  
Wintering Areas ◽  
Wintering Area ◽  
Suitable Habitats

Local studies have shown that the distribution of red knots Calidris canutus across intertidal mudflats is consistent with the predictions of an ideal distribution, but not a free distribution. Here, we scale up the study of feeding distributions to their entire wintering area in western Europe. Densities of red knots were compared among seven wintering sites in The Netherlands, UK and France, where the available mollusc food stocks were also measured and from where diets were known. We tested between three different distribution models that respectively assumed (i) a uniform distribution of red knots over all areas, (ii) a uniform distribution across all suitable habitat (based on threshold densities of harvestable mollusc prey), and (iii) an ideal and free distribution (IFD) across all suitable habitats. Red knots were not homogeneously distributed across the different European wintering areas, also not when considering suitable habitats only. Their distribution was best explained by the IFD model, suggesting that the birds are exposed to interference and have good knowledge about their resource landscape at the spatial scale of NW Europe, and that the costs of movement between estuaries, at least when averaged over a whole winter, are negligible.

scholarly journals Spatial Habitat Shifts of Oceanic Cephalopod (Ommastrephes bartramii) in Oscillating Climate

2020 ◽  
Vol 12 (3) ◽  
pp. 521
Author(s):  
Irene D. Alabia ◽  
Sei-Ichi Saitoh ◽  
Hiromichi Igarashi ◽  
Yoichi Ishikawa ◽  
Yutaka Imamura
Keyword(s):  
Temporal Trend ◽  
Environmental Changes ◽  
Marine Ecosystem ◽  
Temporal Trends ◽  
Suitable Habitat ◽  
Ecosystem Structure ◽  
Ommastrephes Bartramii ◽  
Distribution Models ◽  
Potential Habitat ◽  
Climate Transitions

Short- and long-term climate oscillations impact seascapes, and hence, marine ecosystem structure and dynamics. Here, we explored the spatio-temporal patterns of potential squid habitat in the western and central North Pacific across inter-decadal climate transitions, coincident with periods of persistent warming and cooling. Potential habitat distributions of Ommastrephes bartramii were derived from the outputs of multi-ensemble species distribution models, developed using the most influential environmental factors to squid distribution and occurrence data. Our analyses captured the underlying temporal trends in potential squid habitat in response to environmental changes transpiring at each climatic transition, regulated by phase shifts in Pacific decadal oscillation (PDO) from 1999–2013. The spatial differences in environmental conditions were apparent across transitions and presumably modulate the local changes in suitable squid habitat over time. Specifically, during a cold to warm PDO shift, decreases in the summer potential habitat (mean rate ± standard deviation: −0.04 ± 0.02 habitat suitability index (HSI)/yr) were observed along the southern edge of the subarctic frontal zone (162°E–172°W). Coincidentally, this area also exhibits a warming trend (mean temporal trend: 0.06 ± 0.21 °C/yr), accompanied with the prevalence of cold-core mesoscale eddies, west of the dateline (mean temporal trend in sea surface height: −0.19 ± 1.05 cm/yr). These conditions potentially generate less favorable foraging habitat for squid. However, a warm-to-cold PDO transition underpins a northward shift of suitable habitat and an eastward shift of regions exhibiting the highest rate of potential squid habitat loss (170–160°W; mean temporal trend: −0.05 ± 0.03 HSI/yr). Nonetheless, the emergence of the areas with increasingly suitable habitat regardless of climate transitions suggests the ecological importance of these regions as potential squid habitat hotspots and climatic refugia.

scholarly journals Climate Change and More Disturbed Land-Use Types will Further the Invasion of a Non-Native Annual Grass, Ventenata Dubia

2021 ◽  
Author(s):  
Arjun Adhikari ◽  
Jane Mangold ◽  
Lisa J. Rew
Keyword(s):  
Land Use ◽  
Suitable Habitat ◽  
Native Plant ◽  
Annual Grass ◽  
Distribution Models ◽  
Native Plant Species ◽  
The Road ◽  
Changing Climate ◽  
Potential Habitat ◽  
Road Corridors

Abstract Many land uses are highly prone to invasion of new non-native plant species under changing climate. Identification of suitable habitat for invasive weeds and their projected infestation extent across different land use cover types under a changing climate is crucial for the broad management goals of prevention, detection, and rapid response. In this study, we adopted an ensemble approach of species distribution models to project potential habitat of the invasive annual grass, Ventenata dubia, along the road corridor of Gallatin county, Montana, USA, under current and future climates. The model prediction of V. dubia habitat was excellent. The climate predictors most correlated with V. dubia occurrence were precipitation, potential evapo-transpiration, relative humidity, vapor pressure deficit, and solar radiation for months during the growing season, and fall germination. The model projected 1,945 and 7,374 km2 under RCP4.5, and 2,306 and 11,050 km2 for road corridors and Gallatin county, respectively. We found that the projected increases in V. dubia infestations were highest for road corridors (239% under RCP4.5 and 302% under RCP8.5) compared to that of Gallatin County (127% under RCP4.5 and 241% under RCP8.5). Among the land class types, the model projected greatest expansion of V. dubia cover across agriculture land with 425% and 484% and grassland with 278% and 442% increase under RCP4.5 and RCP8.5, respectively. We conclude that V. dubia with a short history of invasion is expanding at an alarming rate challenging the status quo and requires greater investment in detection and monitoring to prevent further expansion.

scholarly journals Predictions of potential geographical distribution and quality ofSchisandra sphenantheraunder climate change

PeerJ ◽  
2016 ◽  
Vol 4 ◽  
pp. e2554 ◽  
Author(s):  
Yanlong Guo ◽  
Haiyan Wei ◽  
Chunyan Lu ◽  
Bei Gao ◽  
Wei Gu
Keyword(s):  
Climate Change ◽  
Medicinal Plants ◽  
Fuzzy Theory ◽  
Plant Distribution ◽  
Suitable Habitat ◽  
Climate Change Scenarios ◽  
Distribution Models ◽  
Entropy Model ◽  
Intergovernmental Panel ◽  
The Future

Climate change will significantly affect plant distribution as well as the quality of medicinal plants. Although numerous studies have analyzed the effect of climate change on future habitats of plants through species distribution models (SDMs), few of them have incorporated the change of effective content of medicinal plants.Schisandra sphenantheraRehd. et Wils. is an endangered traditional Chinese medical plant which is mainly located in the Qinling Mountains. Combining fuzzy theory and a maximum entropy model, we obtained current spatial distribution of quality assessment forS. spenanthera. Moreover, the future quality and distribution ofS. spenantherawere also projected for the periods 2020s, 2050s and 2080s under three different climate change scenarios (SRES-A1B, SRES-A2 and SRES-B1 emission scenarios) described in the Special Report on Emissions Scenarios (SRES) of IPCC (Intergovernmental Panel on Climate Change). The results showed that the moderately suitable habitat ofS. sphenantheraunder all climate change scenarios remained relatively stable in the study area. The highly suitable habitat ofS. sphenantherawould gradually decrease in the future and a higher decline rate of the highly suitable habitat area would occur under climate change scenarios SRES-A1B and SRES-A2. The result suggested that in the study area, there would be no more highly suitable habitat areas forS. sphenantherawhen the annual mean temperature exceeds 20 °C or its annual precipitation exceeds 1,200 mm. Our results will be influential in the future ecological conservation and management ofS. sphenantheraand can be taken as a reference for habitat suitability assessment research for other medicinal plants.

Mapping Arctic clam abundance using multiple datasets, models, and a spatially explicit accuracy assessment

2019 ◽  
Vol 76 (7) ◽  
pp. 2349-2361
Author(s):  
Benjamin Misiuk ◽  
Trevor Bell ◽  
Alec Aitken ◽  
Craig J Brown ◽  
Evan N Edinger
Keyword(s):  
Spatial Autocorrelation ◽  
Cross Validation ◽  
Predictive Accuracy ◽  
Accuracy Assessment ◽  
Small Scale ◽  
Suitable Habitat ◽  
Distribution Models ◽  
Management Tools ◽  
Seabed Topography ◽  
Leave One Out

Abstract Species distribution models are commonly used in the marine environment as management tools. The high cost of collecting marine data for modelling makes them finite, especially in remote locations. Underwater image datasets from multiple surveys were leveraged to model the presence–absence and abundance of Arctic soft-shell clam (Mya spp.) to support the management of a local small-scale fishery in Qikiqtarjuaq, Nunavut, Canada. These models were combined to predict Mya abundance, conditional on presence throughout the study area. Results suggested that water depth was the primary environmental factor limiting Mya habitat suitability, yet seabed topography and substrate characteristics influence their abundance within suitable habitat. Ten-fold cross-validation and spatial leave-one-out cross-validation (LOO CV) were used to assess the accuracy of combined predictions and to test whether this was inflated by the spatial autocorrelation of transect sample data. Results demonstrated that four different measures of predictive accuracy were substantially inflated due to spatial autocorrelation, and the spatial LOO CV results were therefore adopted as the best estimates of performance.

scholarly journals Distribution, ecology and conservation of an endangered Andean hummingbird: the Violet-throated Metaltail (Metallura baroni)

2009 ◽  
Vol 19 (1) ◽  
pp. 63-76 ◽  
Author(s):  
BORIS A. TINOCO ◽  
PEDRO X. ASTUDILLO ◽  
STEVEN C. LATTA ◽  
CATHERINE H. GRAHAM
Keyword(s):  
Suitable Habitat ◽  
Species Occurrence ◽  
Entropy Model ◽  
Maxent Model ◽  
The North ◽  
The Andes ◽  
Guide Field ◽  
South Central ◽  
Detailed Assessment ◽  
Endangered Status

SummaryThe Violet-throated MetaltailMetallura baroniis a high altitude hummingbird endemic to south-central Ecuador currently considered globally ‘Endangered’. Here we present the first detailed assessment of its distribution, ecology and conservation. We first used a maximum entropy model (Maxent model) to create a predicted distribution for this species based on very limited species occurrence data. We used this model to guide field surveys for the species between April and October 2006. We found a positive relationship between model values and species presence, indicating that the model was a useful tool to predict species occurrence and guide exploration. In the sites where the metaltail was found we gathered data on its habitat requirements, food resources and behaviour. Our results indicate that Violet-throated Metaltail is restricted to the Western Cordillera of the Andes Mountains in Azuay and Cañar provinces of Ecuador, with an area of extent of less than 2,000 km2. Deep river canyons to the north and south, lack of suitable habitat, and potential interspecific competition in the east may limit the bird's distribution. The species occurred in three distinct habitats, includingPolylepiswoodland, the upper edge of the montane forest, and in shrubby paramo, but we found no difference in relative abundance among these habitats. The metaltail seems to tolerate moderate human intervention in its habitats as long as some native brushy cover is maintained. We found thatBrachyotumsp.,Berberissp., andBarnadesiasp. were important nectar resources. The ‘Endangered’ status of this species is supported due to its restricted distribution in fragmented habitats which are under increasing human pressures.

scholarly journals An updated understanding of Texas bumble bee (Hymenoptera: Apidae) species presence and potential distributions in Texas, USA

PeerJ ◽  
2017 ◽  
Vol 5 ◽  
pp. e3612 ◽  
Author(s):  
Jessica L. Beckham ◽  
Samuel Atkinson
Keyword(s):  
Citizen Science ◽  
Species Distributions ◽  
Field Studies ◽  
The United States ◽  
Bumble Bee ◽  
Suitable Habitat ◽  
Distribution Models ◽  
Species List ◽  
Central Texas ◽  
Declining Species

Texas is the second largest state in the United States of America, and the largest state in the contiguous USA at nearly 700,000 sq. km. Several Texas bumble bee species have shown evidence of declines in portions of their continental ranges, and conservation initiatives targeting these species will be most effective if species distributions are well established. To date, statewide bumble bee distributions for Texas have been inferred primarily from specimen records housed in natural history collections. To improve upon these maps, and help inform conservation decisions, this research aimed to (1) update existing Texas bumble bee presence databases to include recent (2007–2016) data from citizen science repositories and targeted field studies, (2) model statewide species distributions of the most common bumble bee species in Texas using MaxEnt, and (3) identify conservation target areas for the state that are most likely to contain habitat suitable for multiple declining species. The resulting Texas bumble bee database is comprised of 3,580 records, to include previously compiled museum records dating from 1897, recent field survey data, and vetted records from citizen science repositories. These data yielded an updated state species list that includes 11 species, as well as species distribution models (SDMs) for the most common Texas bumble bee species, including two that have shown evidence of range-wide declines: B. fraternus (Smith, 1854) and B. pensylvanicus (DeGeer, 1773). Based on analyses of these models, we have identified conservation priority areas within the Texas Cross Timbers, Texas Blackland Prairies, and East Central Texas Plains ecoregions where suitable habitat for both B. fraternus and B. pensylvanicus are highly likely to co-occur.

scholarly journals The modeled distribution of corals and sponges surrounding the Salas y Gómez and Nazca ridges with implications for high seas conservation

PeerJ ◽  
2021 ◽  
Vol 9 ◽  
pp. e11972
Author(s):  
Samuel Georgian ◽  
Lance Morgan ◽  
Daniel Wagner
Keyword(s):  
Suitable Habitat ◽  
Distribution Models ◽  
Seafloor Topography ◽  
Saturation State ◽  
Direct Observations ◽  
Rich Diversity ◽  
Spatial Management ◽  
Phosphate Silicate ◽  
Glass Sponges ◽  
Suitable Habitats

The Salas y Gómez and Nazca ridges are two adjacent seamount chains off the west coast of South America that collectively contain more than 110 seamounts. The ridges support an exceptionally rich diversity of benthic and pelagic communities, with the highest level of endemism found in any marine environment. Despite some historical fishing in the region, the seamounts are relatively pristine and represent an excellent conservation opportunity to protect a global biodiversity hotspot before it is degraded. One obstacle to effective spatial management of the ridges is the scarcity of direct observations in deeper waters throughout the region and an accompanying understanding of the distribution of key taxa. Species distribution models are increasingly used tools to quantify the distributions of species in data-poor environments. Here, we focused on modeling the distribution of demosponges, glass sponges, and stony corals, three foundation taxa that support large assemblages of associated fauna through the creation of complex habitat structures. Models were constructed at a 1 km2 resolution using presence and pseudoabsence data, dissolved oxygen, nitrate, phosphate, silicate, aragonite saturation state, and several measures of seafloor topography. Highly suitable habitat for each taxa was predicted to occur throughout the Salas y Gómez and Nazca ridges, with the most suitable habitat occurring in small patches on large terrain features such as seamounts, guyots, ridges, and escarpments. Determining the spatial distribution of these three taxa is a critical first step towards supporting the improved spatial management of the region. While the total area of highly suitable habitat was small, our results showed that nearly all of the seamounts in this region provide suitable habitats for deep-water corals and sponges and should therefore be protected from exploitation using the best available conservation measures.

scholarly journals Lowland tapir distribution and habitat loss in South America

2015 ◽  
Author(s):  
Jose Luis Passos Cordeiro ◽  
José MV Fragoso ◽  
Danielle Crawshaw ◽  
Luiz Flamarion B Oliveira
Keyword(s):  
South America ◽  
Protected Areas ◽  
Habitat Loss ◽  
Habitat Suitability ◽  
Distribution Patterns ◽  
Distribution Models ◽  
Potential Habitat ◽  
Geographical Regions ◽  
Suitability Maps ◽  
Complex Relationships

The development of species distribution models (SDMs) can help conservation efforts by generating potential distributions and identifying areas of high environmental suitability for protection. Our study presents a rigorously derived distribution and habitat map for lowland tapir in South America. We also describe the potential habitat suitability of various geographical regions and habitat loss, inside and outside of protected areas network. Two different SDM approaches, MAXENT and ENFA, produced relative different Habitat Suitability Maps for the lowland tapir. While MAXENT was efficient at identifying areas as suitable or unsuitable, it was less efficient (when compared to the results by ENFA) at identifying the gradient of habitat suitability. MAXENT is a more multifaceted technique that establishes more complex relationships between dependent and independent variables. Our results demonstrate that for at least one species, the lowland tapir, the use of a simple consensual approach (average of ENFA and MAXENT models outputs) better reflected its current distribution patterns. The Brazilian ecoregions have the highest habitat loss for the tapir. Cerrado and Atlantic Forest account for nearly half (48.19%) of the total area lost. The Amazon region contains the largest area under protection, and the most extensive remaining habitat for the tapir, but also showed high levels of habitat loss outside protected areas, which increases the importance of support for proper management.

scholarly journals Combining Deforestation and Species Distribution Models to Improve Measures of Chimpanzee Conservation Impacts of REDD: A Case Study from Ntakata Mountains, Western Tanzania

Forests ◽  
2020 ◽  
Vol 11 (11) ◽  
pp. 1195
Author(s):  
Rebecca Dickson ◽  
Marc Baker ◽  
Noémie Bonnin ◽  
David Shoch ◽  
Benjamin Rifkin ◽  
...  
Keyword(s):  
Biodiversity Conservation ◽  
Species Distribution ◽  
Carbon Emissions ◽  
Species Distribution Models ◽  
Cost Effective ◽  
Climate Mitigation ◽  
Suitable Habitat ◽  
Distribution Models ◽  
Western Tanzania

Projects to reduce emissions from deforestation and degradation (REDD) are designed to reduce carbon emissions through avoided deforestation and degradation, and in many cases, to produce additional community and biodiversity conservation co-benefits. While these co-benefits can be significant, quantifying conservation impacts has been challenging, and most projects use simple species presence to demonstrate positive biodiversity impact. Some of the same tools applied in the quantification of climate mitigation benefits have relevance and potential application to estimating co-benefits for biodiversity conservation. In western Tanzania, most chimpanzees live outside of national park boundaries, and thus face threats from human activity, including competition for suitable habitat. Through a case study of the Ntakata Mountains REDD project in western Tanzania, we demonstrate a combined application of deforestation modelling with species distribution models to assess forest conservation benefits in terms of avoided carbon emissions and improved chimpanzee habitat. The application of such tools is a novel approach that we argue permits the better design of future REDD projects for biodiversity co-benefits. This approach also enables project developers to produce the more manageable, accurate and cost-effective monitoring, reporting and verification of project impacts that are critical to verification under carbon standards.

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