scholarly journals Optimizing the conservation of migratory species over their full annual cycle

2018 ◽  
Author(s):  
R. Schuster ◽  
S. Wilson ◽  
A.D. Rodewal ◽  
P. Arcese ◽  
D. Fink ◽  
...  
Keyword(s):  
Annual Cycle ◽  
Migratory Birds ◽  
Leading Edge ◽  
Habitat Associations ◽  
Western Hemisphere ◽  
Migratory Species ◽  
Land Area ◽  
Conservation Targets ◽  
Trade Offs ◽  
Novel Approach

AbstractLimited knowledge of the distribution, abundance, and habitat associations of migratory species introduces uncertainty about the most effective conservation actions. We used Neotropical migratory birds as a model group to evaluate contrasting approaches to land prioritization to support ≥30% of the global abundances of 117 species throughout the annual cycle in the Western hemisphere. Conservation targets were achieved in 43% less land area in plans based on annual vs. weekly optimizations. Plans agnostic to population structure required comparatively less land area to meet targets, but at the expense of representation. Less land area was also needed to meet conservation targets when human-dominated lands were included rather than excluded from solutions. Our results point to key trade-offs between efforts minimizing the opportunity costs of conservation vs. those ensuring spatiotemporal representation of populations, and demonstrate a novel approach to the conservation of migratory species based on leading-edge abundance models and linear programming to identify portfolios of priority landscapes and inform conservation planners.

Constrained multi-objective aerofoil design using a multi-level optimisation strategy

2015 ◽  
Vol 119 (1217) ◽  
pp. 833-854
Author(s):  
L. Cameron ◽  
J. Early ◽  
R. McRoberts ◽  
M. Price
Keyword(s):  
Leading Edge ◽  
Boundary Layer Transition ◽  
Layer Transition ◽  
Multi Objective ◽  
Trade Offs ◽  
Novel Approach ◽  
Design Variables ◽  
Business Jet ◽  
Global And Local ◽  
Local Optimisation

AbstractA novel approach for the multi-objective design optimisation of aerofoil profiles is presented. The proposed method aims to exploit the relative strengths of global and local optimisation algorithms, whilst using surrogate models to limit the number of computationally expensive CFD simulations required. The local search stage utilises a re-parameterisation scheme that increases the flexibility of the geometry description by iteratively increasing the number of design variables, enabling superior designs to be generated with minimal user intervention. Capability of the algorithm is demonstrated via the conceptual design of aerofoil sections for use on a lightweight laminar flow business jet. The design case is formulated to account for take-off performance while reducing sensitivity to leading edge contamination. The algorithm successfully manipulates boundary layer transition location to provide a potential set of aerofoils that represent the trade-offs between drag at cruise and climb conditions in the presence of a challenging constraint set. Variations in the underlying flow physics between Pareto-optimal aerofoils are examined to aid understanding of the mechanisms that drive the trade-offs in objective functions.

scholarly journals Prioritize diversity or declining species? Trade-offs and synergies in spatial planning for the conservation of migratory birds in the face of land cover change

2018 ◽  
Author(s):  
S Wilson ◽  
R. Schuster ◽  
A.D. Rodewald ◽  
J.R. Bennett ◽  
A.C Smith ◽  
...  
Keyword(s):  
Species Diversity ◽  
Land Cover ◽  
Central America ◽  
Land Cover Change ◽  
Anthropogenic Impact ◽  
Migratory Birds ◽  
Agricultural Landscapes ◽  
Western Hemisphere ◽  
Trade Offs ◽  
High Species Diversity

AbstractStemming biodiversity loss requires strategic conservation guided by well-articulated and achievable targets, whether they be proactive (e.g., protect diverse places) or reactive (e.g., protect threatened species). Both types of targets can be effective, but there are trade-offs, especially for broadly-distributed ecosystems or taxa, such as migratory species, a group for which conservation has been challenged by limited knowledge of distributions throughout the annual cycle. We combined novel spatiotemporal distribution models with population trend data to first examine focal areas for the conservation of Neotropical migratory birds (n=112 species) during the non-breeding period in the Western Hemisphere based on a proactive approach (highest diversity) versus a reactive approach (strongest declines) to conservation. For the focal areas, we then assessed the extent of recent anthropogenic impact, protected area status and projected future changes in land cover using three shared socioeconomic pathways (Sustainability=SSP1, Business-as-usual=SSP2, Regional nationalism=SSP3). Spatial priorities were strikingly different when targeting areas of high species diversity, emphasizing southern Mexico and northern Central America, versus areas with more severe declines across species, emphasizing the Andean cordilleras of South America. Only a fraction of the non-breeding region (1.4%) met targets for diversity and decline, mostly in southern Central America. Current levels of protection were similar for the two targets. Areas prioritized to conserve high species diversity have experienced less recent anthropogenic impact than areas prioritized for decline but are predicted to experience more rapid land conversion to less suitable open, agricultural landscapes in the next three decades under both an SSP1 and SSP2 scenario. Only the SSP3 scenario projected similar conversion rates for the two targets. Our findings indicate how even within taxa, efficient conservation efforts will depend on the careful consideration of desired targets combined with reliable predictions about the locations and types of land cover change under alternative socioeconomic futures.

scholarly journals Travelling on a budget: predictions and ecological evidence for bottlenecks in the annual cycle of long-distance migrants

2007 ◽  
Vol 363 (1490) ◽  
pp. 247-266 ◽  
Author(s):  
Deborah M Buehler ◽  
Theunis Piersma
Keyword(s):  
Annual Cycle ◽  
Migratory Birds ◽  
Driving Forces ◽  
Long Distance ◽  
Annual Cycles ◽  
Calidris Canutus ◽  
Trade Offs ◽  
Breeding Grounds ◽  
Breeding Plumage ◽  
Red Knot

Long-distance migration, and the study of the migrants who undertake these journeys, has fascinated generations of biologists. However, many aspects of the annual cycles of these migrants remain a mystery as do many of the driving forces behind the evolution and maintenance of the migrations themselves. In this article we discuss nutritional, energetic, temporal and disease - risk bottlenecks in the annual cycle of long-distance migrants, taking a sandpiper, the red knot Calidris canutus , as a focal species. Red knots have six recognized subspecies each with different migratory routes, well-known patterns of connectivity and contrasting annual cycles. The diversity of red knot annual cycles allows us to discuss the existence and the effects of bottlenecks in a comparative framework. We examine the evidence for bottlenecks focusing on the quality of breeding plumage and the timing of moult as indicators in the six subspecies. In terms of breeding plumage coloration, quality and timing of prealternate body moult (from non-breeding into breeding plumage), the longest migrating knot subspecies, Calidris canutus rogersi and Calidris canutus rufa , show the greatest impact of bottlenecking. The same is true in terms of prebasic body moult (from breeding into non-breeding plumage) which in case of both C. c. rogersi and C. c. rufa overlaps with southward migration and may even commence in the breeding grounds. To close our discussion of bottlenecks in long-distance migrants, we make predictions about how migrants might be impacted via physiological ‘trade-offs’ throughout the annual cycle, using investment in immune function as an example. We also predict how bottlenecks may affect the distribution of mortality throughout the annual cycle. We hope that this framework will be applicable to other species and types of migrants, thus expanding the comparative database for the future evaluation of seasonal selection pressures and the evolution of annual cycles in long-distance migrants. Furthermore, we hope that this synthesis of recent advancements in the knowledge of red knot annual cycles will prove useful in the ongoing attempts to model annual cycles in migratory birds.

scholarly journals Population trends inVermivorawarblers are linked to strong migratory connectivity

2018 ◽  
Vol 115 (14) ◽  
pp. E3192-E3200 ◽  
Author(s):  
Gunnar R. Kramer ◽  
David E. Andersen ◽  
David A. Buehler ◽  
Petra B. Wood ◽  
Sean M. Peterson ◽  
...  
Keyword(s):  
Annual Cycle ◽  
Migratory Birds ◽  
Population Trends ◽  
Limiting Factors ◽  
Migratory Connectivity ◽  
Migratory Species ◽  
Vermivora Chrysoptera ◽  
Breeding Populations ◽  
Migratory Songbirds ◽  
Weak Connectivity

Migratory species can experience limiting factors at different locations and during different periods of their annual cycle. In migratory birds, these factors may even occur in different hemispheres. Therefore, identifying the distribution of populations throughout their annual cycle (i.e., migratory connectivity) can reveal the complex ecological and evolutionary relationships that link species and ecosystems across the globe and illuminate where and how limiting factors influence population trends. A growing body of literature continues to identify species that exhibit weak connectivity wherein individuals from distinct breeding areas co-occur during the nonbreeding period. A detailed account of a broadly distributed species exhibiting strong migratory connectivity in which nonbreeding isolation of populations is associated with differential population trends remains undescribed. Here, we present a range-wide assessment of the nonbreeding distribution and migratory connectivity of two broadly dispersed Nearctic-Neotropical migratory songbirds. We used geolocators to track the movements of 70Vermivorawarblers from sites spanning their breeding distribution in eastern North America and identified links between breeding populations and nonbreeding areas. Unlike blue-winged warblers (Vermivora cyanoptera), breeding populations of golden-winged warblers (Vermivora chrysoptera) exhibited strong migratory connectivity, which was associated with historical trends in breeding populations: stable for populations that winter in Central America and declining for those that winter in northern South America.

Jellyfish distribution and abundance in relation to the physical habitat of Jellyfish Lake, Palau

2018 ◽  
Vol 34 (1) ◽  
pp. 17-31 ◽  
Author(s):  
Megan A. Cimino ◽  
Sharon Patris ◽  
Gerda Ucharm ◽  
Lori J. Bell ◽  
Eric Terrill
Keyword(s):  
Autonomous Underwater Vehicle ◽  
Size Fraction ◽  
Underwater Vehicle ◽  
Habitat Associations ◽  
Physical Habitat ◽  
Uv Damage ◽  
Tourist Destination ◽  
Novel Approach ◽  
Abundance Estimates ◽  
Acoustic Surveys

Abstract:Animals often select for habitats that increase their chance of survival by balancing the need to acquire food, reproduce and avoid predation. Perennial blooms of golden jellyfish (Mastigias papua etpisoni) are present in Jellyfish Lake, Palau, a popular tourist destination. Based on the species’ economic importance and unusual behavioural complexity, increased understanding of jellyfish habitat selection is necessary. We used a novel approach, a REMUS autonomous underwater vehicle, to quantify jellyfish distribution, abundance and habitat, and compared these findings to traditional methods. Midday acoustic surveys showed jellyfish distribution was patchy and the population resided mainly on the eastern side of the lake, as it is known that jellyfish migrate eastward towards the sun. Highest vertical densities of jellyfish were at 6–7 m, potentially to mitigate UV damage or photoinhibition of their photosymbionts, suggesting a coupling exists between their vertical distribution and water properties. Abundance estimates of jellyfish were ~2.75 and ~7.1 million (~2 million excluding bell diameters <1 cm) from acoustic and net samples, suggesting the methodology employed underestimated the population's smaller size fraction and non-synoptic surveys could impact estimates due to unresolved patchiness. Our approach could investigate population dynamics, behaviour or habitat associations on fine scales.

scholarly journals Optimizing the conservation of migratory species over their full annual cycle

2019 ◽  
Vol 10 (1) ◽  
Author(s):  
Richard Schuster ◽  
Scott Wilson ◽  
Amanda D. Rodewald ◽  
Peter Arcese ◽  
Daniel Fink ◽  
...  
Keyword(s):  
Annual Cycle ◽  
Migratory Species

scholarly journals Interspecific demographic trade-offs and soil-related habitat associations of tree species along resource gradients

2007 ◽  
Vol 96 (1) ◽  
pp. 192-203 ◽  
Author(s):  
Sabrina E. Russo ◽  
Patrick Brown ◽  
Sylvester Tan ◽  
Stuart J Davies
Keyword(s):  
Tree Species ◽  
Habitat Associations ◽  
Resource Gradients ◽  
Trade Offs

scholarly journals Climate change relaxes the time constraints for late-born offspring in a long-distance migrant

2016 ◽  
Vol 283 (1839) ◽  
pp. 20161366 ◽  
Author(s):  
Barbara M. Tomotani ◽  
Phillip Gienapp ◽  
Domien G. M. Beersma ◽  
Marcel E. Visser
Keyword(s):  
Climate Change ◽  
Annual Cycle ◽  
Migratory Birds ◽  
Climate Change Impacts ◽  
Egg Laying ◽  
Time Constraints ◽  
Long Distance ◽  
Hatch Date ◽  
Breeding Bird ◽  
And Migration

Animals in seasonal environments need to fit their annual-cycle stages, such as moult and migration, in a tight schedule. Climate change affects the phenology of organisms and causes advancements in timing of these annual-cycle stages but not necessarily at the same rates. For migratory birds, this can lead to more severe or more relaxed time constraints in the time from fledging to migration, depending on the relative shifts of the different stages. We tested how a shift in hatch date, which has advanced due to climate change, impacts the organization of the birds' whole annual cycle. We experimentally advanced and delayed the hatch date of pied flycatcher chicks in the field and then measured the timing of their annual-cycle stages in a controlled laboratory environment. Hatch date affected the timing of moult and pre-migratory fattening, but not migration. Early-born birds hence had a longer time to fatten up than late-born ones; the latter reduced their interval between onset of fattening and migration to be able to migrate at the same time as the early-born birds. This difference in time constraints for early- and late-born individuals may explain why early-born offspring have a higher probability to recruit as a breeding bird. Climate change-associated advancements of avian egg-lay dates, which in turn advances hatch dates, can thus reduce the negative fitness consequences of reproducing late, thereby reducing the selection for early egg-laying migratory birds.

To breed or not: a novel approach to estimate breeding propensity and potential trade-offs in an Arctic-nesting species

Ecology ◽  
2014 ◽  
Vol 95 (10) ◽  
pp. 2745-2756 ◽  
Author(s):  
Guillaume Souchay ◽  
Gilles Gauthier ◽  
Roger Pradel
Keyword(s):  
Trade Offs ◽  
Novel Approach ◽  
Breeding Propensity
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