scholarly journals Whole-Genomes From the Extinct Xerces Blue Butterfly Reveal Low Diversity and Long-Term Population Decline

2021 ◽  
Author(s):  
Toni de-Dios ◽  
Claudia Fontsere ◽  
Pere Renom ◽  
Josefin Stiller ◽  
Laia Llovera Nadal ◽  
...  
Keyword(s):  
Population Decline ◽  
Whole Genomes ◽  
Low Diversity ◽  
Blue Butterfly

scholarly journals Population of Puerto Rico not displaced by Hurricanes (for now): It’s the economy

2019 ◽  
Author(s):  
Matt Kaneshiro ◽  
Collin McCarter ◽  
Mario Marazzi ◽  
Alexis R Santos-Lozada
Keyword(s):  
Puerto Rico ◽  
Population Change ◽  
Population Decline ◽  
Data Sources ◽  
Quality Data ◽  
Economic Data ◽  
High Quality Data ◽  
Economic Downturns ◽  
Employment Trends

In September 2017, Hurricane Maria made landfall on Puerto Rico and caused 102 billion worth of damages, demolishing the electric grid and severely affecting essential daily services that continued as of the second half of 2019. Amidst the chaos, analysts were expected to provide stakeholders with impact estimates immediately following the hurricane. Unfortunately, this strong need for fast information after the disaster coincided with limited options for high-quality data sources to help stakeholders address challenges such as resource allocation and bond-pricing. Given the stabilization of data sources since the hurricanes, this paper examines historical demographic and economic data to give a long-term view of population change in Puerto Rico. First, we juxtapose population, employment, hurricanes and significant economic events to make the argument that the clearest driver of population decline in Puerto Rico is simply the economic health of the island (i.e. employment). Second, we focus on Pre- and Post-Hurricane Irma/Maria migration estimates to highlight the spike in outmigration following the hurricanes, as well as the, return immigration in the first half of the first half of 2018. Finally, we study historical net outmigration and employment trends to illustrate the short-lived outmigration impacts of hurricanes while also highlighting the long-term outmigration impacts of economic downturns. In short, we argue that the primary reason people are leaving Puerto Rico is the struggling economy and not hurricane-related destruction. The hurricanes simply exacerbated the economic-related outmigration trends and we believe that any serious plans for Puerto Rico’s restoration must include special attention to stimulate the economy.

scholarly journals The rise and fall of Anopheles arabiensis (Diptera: Culicidae) in a Tanzanian village

1995 ◽  
Vol 85 (1) ◽  
pp. 37-44 ◽  
Author(s):  
J.D. Charlwood ◽  
J. Kihonda ◽  
S. Sama ◽  
P.F. Billingsley ◽  
H. Hadji ◽  
...  
Keyword(s):  
Life Cycle ◽  
Survival Rate ◽  
Anopheles Arabiensis ◽  
Light Trapping ◽  
Population Decline ◽  
Malaria Vectors ◽  
General Applicability ◽  
Dry Spell ◽  
The Village

AbstractThe continual recruitment of new individuals makes it difficult to study both the survival of multivoltine mosquitoes, and the size of the infectious reservoir in narural populations of malaria vectors. During long-term surveillance of a population of Anopheles gambiae Giles sensu lato in a Tanzanian village by daily light trapping, a temporary dry spell resulted in the cessation of recruitment for a period of 33 days, and a decline in numbers of A. arabiensis Patton caught from over 2000 to less than 10 in a sentinel house. Traps placed elsewhere in the village indicated similar proportionate declines although numbers caught varied according to location. A survival rate of 83% per day was estimated from the rate of population decline. Survival was unrelated to the size of the mosquitoes. The infectious reservoir (the chance of a mosquito acquiring an infection) was estimated to be 2% per feed. The exploitation of fortuitous events which temporarily eliminate a single stage in the life cycle has general applicability in the study of the bionomics of multivoltine insects.

Muskellunge Management: Fifty Years of Cooperation Among Anglers, Scientists, and Fisheries Biologists

2017 ◽  
Keyword(s):  
Size Structure ◽  
Population Decline ◽  
Round Goby ◽  
Management Plan ◽  
Neogobius Melanostomus ◽  
Before And After ◽  
Catch Rates ◽  
Survival Studies ◽  
St Lawrence River

<em>Abstract</em>.— Long-term research indicates a significant and ongoing decline within the upper St. Lawrence River Muskellunge <em>Esox masquinongy </em>population. Index surveys show a sharp reduction in catch of both spawning adults and age-0 Muskellunge, and catch rates by anglers have similarly declined while harvest remains low. Other changes associated with population decline include presence of fewer female adult Muskellunge and a change in adult Muskellunge size structure (increase in proportion of fish <1,016 mm) in addition to more large individuals greater than 1,372 mm. A significant adult die-off occurred from 2005 to 2008 (103 adults recovered in U.S. and Canadian waters) concomitant with an outbreak of viral hemorrhagic septicemia (VHS). These population changes were also temporally correlated with detection and proliferation of invasive Round Goby <em>Neogobius melanostomus</em>, a known VHS virus (VHSV) reservoir, egg predator, and competitor with native fishes. Comparisons of index netting before and after VHSV and Round Goby invasions suggest a direct link to the decline, but because these are correlations, we can only explore these effects. To examine the viability of Muskellunge nursery sites, we repeated survival studies conducted in the early 1990s with experimental releases of advanced fry at four locations during 2013–2015. Findings indicate contribution to age-0 populations, but catches poststocking (wild and stocked) were lower compared to the 1990s. We review information regarding potential stressors, including VHSV and Round Goby invasion, and conclude that their combined effects have created significant uncertainty and challenges to sustainable management of the Muskellunge population. In response, the St. Lawrence River Muskellunge management plan should be updated with a focus on restoration of the declining Muskellunge stock. Recommended actions target advancing conservation and restoration of critical habitat, restoring lost subpopulations, and reducing mortality associated with angling (e.g., from handling and harvest).

Abundance, distribution and reproduction of the Data-Deficient species (Squalus blainville) around Sardinia Island (central western Mediterranean Sea) as a contribution to its conservation

2021 ◽  
Vol 72 (1) ◽  
pp. 118 ◽  
Author(s):  
Martina Francesca Marongiu ◽  
Cristina Porcu ◽  
Andrea Bellodi ◽  
Rita Cannas ◽  
Pierluigi Carbonara ◽  
...  
Keyword(s):  
Population Decline ◽  
Temporal Trends ◽  
Reproductive Potential ◽  
Western Mediterranean ◽  
Biological Traits ◽  
Abundance Distribution ◽  
Western Mediterranean Sea ◽  
Fishery Data ◽  
Data Deficient

Data-Deficient (DD) species are currently under threat because of the paucity of information regarding their abundance, distribution and biological traits. In this study we analysed temporal trends and bioecological features of the DD shark, Squalus blainville. Biological and fishery data were collected through two different scientific surveys spanning 1994–2018 and commercial hauls around Sardinia Island (central western Mediterranean) from 2008 to 2018. The analysis of temporal trends based on abundance data revealed a significant population decline over time. The late attainment of maturity and low fecundity of S. blainville are suspected to have contributed to making it highly vulnerable to overfishing. No bathymetric segregation by sex and size was found. However, the almost exclusive presence of pregnant females south-west of Sardinia could be due to sexual spatial segregation. This is also supported by histological findings showing long-term sperm storage to ensure the persistence of the species when females and males are separated. The documented decline of this species, its low reproductive potential and similarities in the depth distribution of immature and mature individuals indicate the need for urgent protection plans for S. blainville in Sardinian waters.

scholarly journals Long-Term Sustainability of a High-Energy, Low-Diversity Crustal Biome

Science ◽  
2006 ◽  
Vol 314 (5798) ◽  
pp. 479-482 ◽  
Author(s):  
L.-H. Lin ◽  
P.-L. Wang ◽  
D. Rumble ◽  
J. Lippmann-Pipke ◽  
E. Boice ◽  
...  
Keyword(s):  
High Energy ◽  
Low Diversity

scholarly journals Nest-site competition and killing by invasive parakeets cause the decline of a threatened bat population

2018 ◽  
Vol 5 (5) ◽  
pp. 172477 ◽  
Author(s):  
Dailos Hernández-Brito ◽  
Martina Carrete ◽  
Carlos Ibáñez ◽  
Javier Juste ◽  
José L. Tella
Keyword(s):  
Native Species ◽  
Population Decline ◽  
Urban Environments ◽  
Strong Impact ◽  
Long Term Effects ◽  
Individual Fitness ◽  
Tree Cavities ◽  
Negative Impacts ◽  
Site Competition

The identification of effects of invasive species is challenging owing to their multifaceted impacts on native biota. Negative impacts are most often reflected in individual fitness rather than in population dynamics of native species and are less expected in low-biodiversity habitats, such as urban environments. We report the long-term effects of invasive rose-ringed parakeets on the largest known population of a threatened bat species, the greater noctule, located in an urban park. Both species share preferences for the same tree cavities for breeding. While the number of parakeet nests increased by a factor of 20 in 14 years, the number of trees occupied by noctules declined by 81%. Parakeets occupied most cavities previously used by noctules, and spatial analyses showed that noctules tried to avoid cavities close to parakeets. Parakeets were highly aggressive towards noctules, trying to occupy their cavities, often resulting in noctule death. This led to a dramatic population decline, but also an unusual aggregation of the occupied trees, probably disrupting the complex social behaviour of this bat species. These results indicate a strong impact through site displacement and killing of competitors, and highlight the need for long-term research to identify unexpected impacts that would otherwise be overlooked.

scholarly journals Population structure and spatial distribution of porbeagles (Lamna nasus) in Irish waters

2019 ◽  
Vol 76 (6) ◽  
pp. 1581-1590 ◽  
Author(s):  
Luke W J Cameron ◽  
William K Roche ◽  
Jonathan D R Houghton ◽  
Paul J Mensink
Keyword(s):  
Population Structure ◽  
Spatial Distribution ◽  
North Atlantic ◽  
Population Decline ◽  
The North ◽  
Aggregation Site ◽  
Show Evidence ◽  
Long Term Trends ◽  
Almost All

Abstract Porbeagles throughout the North Atlantic have experienced severe population decline through overfishing, with the northeastern population listed as critically endangered. Management of this population is constrained by the paucity of data on porbeagle population structure, distribution and behaviour in this region. Here we use a long-term (47 year) Irish capture-mark-recapture dataset to investigate the population structure, spatial distribution and seasonal movements of this species. From 1970–2017, a total of 268 sharks (9 recaptures) were ID tagged, with most individuals likely being juvenile based on length at maturity estimates (mean total length = 143.9 cm, SD = 35.4). Almost all captures were recorded at three distinct locations near angling hubs along the south, west and north coasts with catches peaking in August. Long-term trends in capture date indicated a shift towards earlier capture dates in the northern site (n = 153). Our findings suggest Irish waters may act as a persistent summer aggregation site for juveniles, which show evidence for seasonal site fidelity, returning to nearby locations between years. These findings demonstrate the utility of such programmes, which can be implemented, with minimal expense by engaging with the angling sector, to elucidate the population structure and distribution of wide-ranging fish species.

scholarly journals The decline of the endemic Fijian crested iguana Brachylophus vitiensis in the Yasawa and Mamanuca archipelagos, western Fiji

Oryx ◽  
2007 ◽  
Vol 41 (1) ◽  
pp. 44-50 ◽  
Author(s):  
Peter S. Harlow ◽  
Martin Fisher ◽  
Marika Tuiwawa ◽  
Pita N. Biciloa ◽  
Jorge M. Palmeirim ◽  
...  
Keyword(s):  
Habitat Loss ◽  
Forest Fires ◽  
Population Decline ◽  
Forest Degradation ◽  
Iucn Red List ◽  
Red List ◽  
Critically Endangered ◽  
Introduced Predators ◽  
Free Ranging

The endemic Fijian crested iguana Brachylophus vitiensis, categorized as Critically Endangered on the IUCN Red List, has been recorded from several islands in western Fiji. We conducted a survey for the crested iguana on 12 uninhabited and five inhabited islands in the Yasawa and Mamanuca archipelagos of western Fiji in September 2000. Night searches for sleeping iguanas along a total of 11.2 km of forest transects suggest that crested iguanas are either extremely rare or extinct on all of these islands. Although we collectively searched a total of 44 km of transect over 123 person hours, we located crested iguanas on only four islands: three small uninhabited islands (all <73 ha) and one large inhabited island (22 km). In July 2003 we resurveyed two islands identified as having the best potential for the long-term conservation of crested iguanas, and found that populations were continuing to decline. We suggest that the scarcity of crested iguanas on all islands surveyed is due to the combination of habitat loss and the introduction of exotic predators. All islands surveyed have free ranging goats, forest fires have occurred repeatedly over the last few decades, and feral cats are established on many islands. To reverse the population decline of this species immediate intervention is required on selected islands to halt continuing forest degradation and to clarify the effects of introduced predators.

Sign in / Sign up

Export Citation Format

Share Document