scholarly journals Breeding dispersal movements of Dupont’s Lark Chersophilus duponti in fragmented landscape

2021 ◽  
pp. 1-11
Author(s):  
CRISTIAN PÉREZ-GRANADOS ◽  
PEDRO SÁEZ-GÓMEZ ◽  
GERMÁN M. LÓPEZ-IBORRA
Keyword(s):  
Survival Rate ◽  
Habitat Management ◽  
Population Connectivity ◽  
Fragmented Landscape ◽  
Adult Bird ◽  
Breeding Dispersal ◽  
Adult Males ◽  
Ebro Valley ◽  
Management Actions ◽  
Dupont’S Lark

Summary Understanding patterns of dispersal behaviour of threatened species is important in conservation biology and population ecology, especially in fragmented landscapes. Dupont’s Lark Chersophilusduponti is a threatened passerine whose European population has declined by around 40% in the last decade. To study natal and breeding dispersal of the species, we used a long-term mark-recapture dataset (2011–2019) and analysed the records of 32 males (39 dispersal movements) and five females (five dispersal movements) captured during the breeding season at Rincón de Ademuz (Valencia, eastern Spain). Adult birds had a median breeding dispersal of 154 m (Q25-Q75 = 70.0–300.3). Among these captures, two adult males dispersed to a new patch of habitat separated by more than 5,800 m. Only one out of 26 nestlings ringed was trapped as an adult bird, which occurred at a site different from the natal territory (4,500 m). Our results show a low breeding dispersal for the species and are, in essence, in agreement with previous studies carried out in the Ebro Valley metapopulation, one of the core areas for the species in Europe. Nonetheless, unlike in the Ebro Valley, we detected movements of adult birds between habitat patches. The low recovery rate of young birds suggests that they left their natal sites and moved outside the study area or that their survival rate was very low. Future studies focused on the post-fledging survival rate and natal dispersal movements are essential to determine effective conservation measures for the species. Habitat management actions in occupied and potential sites should be carried out close to the areas inhabited by the species to increase the success rate of the interventions and the effective dispersal and therefore population connectivity.

There’s no place like home — site fidelity by female moose (Alces alces) in central Ontario, Canada

2021 ◽  
pp. 557-563
Author(s):  
A.A.D. McLaren ◽  
B.R. Patterson
Keyword(s):  
Global Positioning System ◽  
Site Fidelity ◽  
Habitat Management ◽  
Alces Alces ◽  
Spatial Scales ◽  
Management Actions ◽  
Global Positioning ◽  
Protective Cover ◽  
System Data ◽  
Provincial Park

Site fidelity is thought to provide increased fitness through familiarity with the distribution of forage, protective cover, breeding and offspring rearing sites, and predators. For moose (Alces alces (Linnaeus, 1758)), previous research has documented fidelity at varying spatial scales. Our objective was to build on this knowledge and assess fidelity by adult female moose in two areas of central Ontario, Canada (Algonquin Provincial Park (APP) and Wildlife Management Unit 49 (WMU49)). We used global positioning system data to generate mean weekly locations for collared moose, then measured the distance between paired weekly locations among consecutive years to evaluate site fidelity. We tested for effects of study area, biological season, moose age, and reproductive status using generalized linear mixed models. Moose demonstrated stronger site fidelity in WMU49, an area with more anthropogenic disturbance, than the protected area, APP. Fidelity was weakest in the winter, but was similar among other seasons and was independent of maternal age and the presence of a calf. Our study highlights the need to consider the scale of site fidelity relative to habitat management. Actions aimed at supporting moose populations might benefit more by protecting habitat classes selected by moose rather than specific sites used by individuals.

Natal and Breeding Dispersal in House Wrens (Troglodytes aedon)

The Auk ◽  
1988 ◽  
Vol 105 (3) ◽  
pp. 480-491 ◽  
Author(s):  
Nancy E. Drilling ◽  
Charles F. Thompson
Keyword(s):  
Reproductive Success ◽  
Natal Dispersal ◽  
Breeding Dispersal ◽  
Adult Males ◽  
Troglodytes Aedon ◽  
Grid Pattern ◽  
Breeding Sites ◽  
House Wrens ◽  
Previous Season ◽  
Central Illinois

Abstract We studied the natal and breeding dispersal of yearling and adult House Wrens (Troglodytes aedon) for 7 yr in central Illinois. The forested study areas contained 910 identical nest boxes placed in a grid pattern. On average 38.1% (n = 643) of the adult males and 23.3% (n = 1,468) of the adult females present in one year returned the next; 2.8% (n = 6,299) of the nestlings that survived to leave the nest returned each year. Adult male (median distance = 67 m) and adult female (median = 134 m) breeding dispersal was less than yearling male (median = 607.5 m) and yearling female (median = 674 m) natal dispersal. Females that returned had produced more offspring the previous season than had nonreturning females, and females that successfully produced at least one chick in their last nesting attempt of the previous season moved shorter distances than did unsuccessful females. There were, however, no consistent differences between returning and nonreturning females in two other measures of reproductive success. Females that were unsuccessful in their last breeding attempt of the previous year were more likely to be successful in their next attempt if they moved two or more territories than if they did not move. Reproductive success did not affect the likelihood that a male would return nor the distance that he moved. The success of subsequent nesting attempts by males was also not related to the distance moved. Inbreeding avoidance may explain differences between breeding and natal dispersal, but it does not explain the lack of difference in dispersal of yearling females and males. Differences between adult and yearling dispersal are best explained by advantages accruing to adults that remain near former breeding sites and by the necessity for yearlings to move farther because of their late return from the wintering grounds. The advantages for adults to reoccupy previous breeding sites are counterbalanced, especially in females, by advantages associated with moving after breeding failure.

Demography of barren-ground grizzly bears

2003 ◽  
Vol 81 (2) ◽  
pp. 294-301 ◽  
Author(s):  
Philip D McLoughlin ◽  
Mitchell K Taylor ◽  
H Dean Cluff ◽  
Robert J Gau ◽  
Robert Mulders ◽  
...  
Keyword(s):  
Survival Rate ◽  
Litter Size ◽  
Birth Interval ◽  
Ursus Arctos ◽  
Survival Rates ◽  
Grizzly Bears ◽  
Adult Males ◽  
Barren Ground ◽  
Rate Of Increase ◽  
The Mean

Between May 1995 and June 1999, we equipped 81 barren-ground grizzly bears (Ursus arctos) with satellite radio collars within a study area of 235 000 km2, centred 400 km northeast of Yellowknife, Northwest Territories, Canada. We used data from radiotelemetry to estimate survival rates, reproductive parameters, and the finite rate of increase of the population (λ). The annual survival rate of adult females was estimated at 0.979 (95% confidence intervals (CI) = 0.955–0.998), while the survival rate of adult males was 0.986 (95% CI = 0.942–1.0). The cub survival rate was 0.737 (95% CI = 0.600–0.844) and the yearling survival rate was 0.683 (95% CI = 0.514–0.821). Cub litter size averaged 2.23 (SE = 0.13, n = 35), while yearling litter size decreased to a mean of 1.86 (SE = 0.12, n = 35). The mean litter size of females with 2-year-olds was 1.85 (SE = 0.15, n = 20). The mean birth interval was 2.8 years (SE = 0.3 years, n = 17). The mean reproductive interval, which is calculated by excluding the loss of whole litters from the sample, was 3.9 years (SE = 0.4 years, n = 9). Mean litter size divided by mean birth interval yielded an annual natality rate of 0.81 cubs per adult female per year. The mean age at first parturition was 8.1 years (SE = 0.5 years, n = 10). We believe the population to be currently stable or slightly increasing (λ = 1.033, 95% CI = 1.008–1.064).

scholarly journals Habitat selection of Capercaillie (Tetrao urogallus) displaying males: Case from Rila Mountain, Bulgaria

2019 ◽  
Vol 2 ◽  
Author(s):  
Dimitar Plachiyski ◽  
Georgi Popgeorgiev ◽  
Stefan Avramov ◽  
Yurii Kornilev
Keyword(s):  
Habitat Selection ◽  
Home Range ◽  
Scots Pine ◽  
Vegetation Cover ◽  
Habitat Management ◽  
Categorical Variables ◽  
Tetrao Urogallus ◽  
Adult Males ◽  
Convex Polygons ◽  
Selection Of

Current habitat management of the peripheral, regionally unique, and isolated Balkan capercaillie Tetrao urogallus rudolfi Dombrowski, 1912 meta-population in Bulgaria is based on obsolete knowledge of the spatial requirements of the species. Thus, we studied the habitat availability and the patterns of use by Capercaillie adult males, at the home range scale to inform and contribute to the conservation-oriented management of the threatened subspecies and its habitats. The field study was conducted during 2014–2015 in the northeastern part of Rila Mtn., Southwestern Bulgaria. Using GPS tags (“Bird 2A”, e-obs Digital Telemetry, Grünwald, Germany), a total of 38,640 GPS fixes from 3 displaying males, associated with one lek were gained. On this basis, we calculated annual and seasonal Minimum Convex Polygons (MCP), traditionally used as a measure of the maximum area of activity. Capercaillie habitat preference was computed using Manly’s habitat selection ratios (w), design III, combined with 90% Bonferroni simultaneous confidence intervals. To calculate habitat selection, we determined surface (Steepness and Exposure), forest stand succession and vegetation cover categorical variables. The habitat and surface layers was rasterized into 8 m square pixels. At the home range (MCP) scale, tagged roosters used vegetation cover non-randomly (annual: Khi2L=5738.89, df=14, p<0.001; winter: Khi2L=3773.28, df=13, p<0.001; summer: Khi2L=3646.32, df=14, p<0.001), and preferred forests dominated by Scots pine and Macedonian pine, such as the annual selection of Scots pine and summer selection of Macedonian pine are significantly different. In terms of forest stage succession, roosters used forest stages non-randomly (annual: Khi2L=3492.57, df=8, p<0.001; winter: Khi2L=2075.18, df=8, p<0.001; summer: Khi2L=1670.1, df=6, p<0.001), and demonstrated clear avoidance of forests stands in age classes: “0 to 40” and “41 to 80” years within the summer and annual ranges. The roosters demonstrated significant preference for southeastern exposure during the winter and annually, and significant overall avoidance of northern exposure, as well as avoidance of north-eastern aspect during the winter and south aspect during the summer (annual: Khi2L=4671.87, df=18, p<0.001; winter: Khi2L=3909.04, df=16, p<0.001; summer: hi2L=3095.84, df=18, p<0.001). The slope class “63.1 to 73o” was not used. In the summer, Capercaillie males significantly preferred slopes within the class “27.1 to 36o” and avoided the classes “0 to 9o”, “9.1 to 18o” and “54.1 to 63o”. The birds also demonstrated significant avoidance of flat terrains within the “0 to 9o” class annually (annual: Khi2L=608.24, df=17, p<0.001; winter: Khi2L=1148.37, df=16, p<0.001; summer: Khi2L=906.54, df=17, p<0.001).

scholarly journals Spatially non-continuous relationships between biological invasion and fragmentation of mangrove forests

2021 ◽  
Author(s):  
Zhen Zhang ◽  
Jing Li ◽  
Yi Li ◽  
Wenwen Liu ◽  
Yuxin Chen ◽  
...  
Keyword(s):  
Salt Marsh ◽  
Biological Invasion ◽  
Large Scale ◽  
Coastal Wetland ◽  
Biodiversity Loss ◽  
Landscape Scale ◽  
Fragmented Landscape ◽  
Mangrove Forests ◽  
Management Actions ◽  
Geographical Variations

Rapid and large-scale biological invasion results in widespread biodiversity loss and degradation of essential ecosystem services, especially in mangrove forests. Recent evidence suggests that the establishment and dispersal of invasive species may exacerbated in fragmented landscape, but the influence of mangrove fragmentation on coastal biological invasion at landscape scale remains largely unknown. Here, using the derived 10-m resolution coastal wetland map in southeast coast of China, we examine the relationships between fragmentation of mangrove forests and salt marsh invasion magnitude and quantify the geographical variations of the relationships across a climatic gradient. Our results show that mangrove forests with small size, large edge proportion, and regular boundary shape tend to suffer more serious salt marsh invasions, indicating a positive correlation between mangrove fragmentation and its invaded magnitude. In particular, such fragmentation-invasion relationships in subtropics are shown to be more intensive than in tropic. Our findings provide the first spatially explicit evidence of the relationships between mangrove fragmentation and biological invasion on a landscape scale, and highlight an urgent need for conservation and management actions to improve mangrove connectivity, which will increase resistance to invasions, especially for small-size subtropical mangrove forests.

scholarly journals Factors affecting waterfowl hunting and harvest at the Evros delta, Greece

2020 ◽  
Vol 150 ◽  
Author(s):  
Savas Kazantzidis ◽  
Christos Astaras ◽  
Ioakim Vasiliadis ◽  
Eleni Makrygianni ◽  
Vassilis Ilias ◽  
...  
Keyword(s):  
Habitat Management ◽  
Weather Conditions ◽  
Abundant Species ◽  
Protected Species ◽  
Factors Affecting ◽  
Management Actions ◽  
Hunting Activity ◽  
Wintering Waterfowl ◽  
Waterfowl Hunting ◽  
The Relationship

The Evros delta is one of the most important wetlands for wintering waterfowl in Greece and the most popular among waterfowl hunters. This study addresses hunting activity and harvest while also investigating the relationship between weather conditions and hunting activity to suggest ways of improving waterfowl management. We counted wintering waterfowl and hunter numbers, and conducted hunter bag surveys during December–February over four hunting seasons. We calculated a 10-day goose and duck Preferential Shooting Index (PSI), which is the ratio of observed number of shot birds to the number of birds expected to have been shot if the birds were shot in proportion to their availability. Common Teal, Mallard and Greater White-fronted Goose were the most abundant species both in the field and in hunter bags. The mean number of hunters/day was 99.9, with each one shooting on average 2.5 birds/day. The overall waterfowl harvested accounted for 1.3% of the total waterfowl population. For geese this proportion was six times higher (8.7%), while for ducks alone and protected species was 1.2% and 1.4% respectively. Geese were shot more often than expected (PSI 6.55), while ducks and protected species were shot according to their availability (PSI 0.86 and 1.02, respectively). Wind speed, precipitation and geese number in the field were the best predictors of overall harvest and number of hunters. To reduce goose overshooting and the probability of protected species being accidentally shot, we suggest habitat management actions for the geese feeding areas and hunters’ awareness raising.

Multinational genetic connectivity identified in western Pacific hawksbill turtles, Eretmochelys imbricata

2018 ◽  
Vol 45 (4) ◽  
pp. 307 ◽  
Author(s):  
Ian Bell ◽  
Michael P. Jensen
Keyword(s):  
Great Barrier Reef ◽  
Conservation Management ◽  
Threat Assessment ◽  
Population Connectivity ◽  
Genetic Connectivity ◽  
Stock Structure ◽  
Barrier Reef ◽  
Long Distance ◽  
Eretmochelys Imbricata ◽  
Management Actions

Context An understanding of the genetic stock structure of wide-ranging marine species is necessary for sound conservation management. Eretmochelys imbricata is Critically Endangered globally, but is among the least studied marine turtles. Reduced population sizes, its long-distance migratory nature between feeding and nesting habitats and poor understanding of its stock structure, biology and anthropogenic impact(s) pose challenges to developing effective conservation strategies for regional conspecifics. Aims Quantification of the population connectivity between specific feeding areas and regional nesting populations is needed for threat assessment and development of mitigation actions. Methods Here, we sequenced the mitochondrial DNA (mtDNA) of 91 immature and adult foraging E. imbricata individuals captured at the Howick Group of islands in the far-northern section of the Great Barrier Reef (nGBR), Queensland, Australia. We used a Bayesian mixed-stock analysis (MSA) approach to determine the contribution of nine regional genetically characterised breeding populations to this feeding aggregation. Key results The MSA estimated that a majority (83%; 95% CI = 70–92%) of feeding E. imbricata had originated from nesting beaches in the Bismarck–Solomon Sea region, whereas only 15% (95% CI = 6–25%) had originated from nGBR rookeries. International reproductive migrations were also corroborated by the return of 18 uniquely numbered titanium flipper tags that had been applied to E. imbricata found foraging in the Howick Group and had swum to rookeries within the Bismarck–Solomon Sea region. These 18 turtles represent 86% of all migration tag–recaptures from the Howick Group. Conclusions We postulate that recent increases in nesting populations within the Solomon Islands may be due to the high level of protection afforded to foraging turtles within the Great Barrier Reef. Implications An understanding of the connectivity between specific feeding areas and nesting populations is necessary to determine threats to animals over their entire life history and, therefore, allow the development of sound conservation management actions.

scholarly journals Retrospective assessment of long-term conservation management of elephants in Addo Elephant National Park, South Africa

Oryx ◽  
2002 ◽  
Vol 36 (3) ◽  
pp. 243-248 ◽  
Author(s):  
Anna M. Whitehouse ◽  
Graham I. H. Kerley
Keyword(s):  
Population Growth ◽  
National Park ◽  
Conservation Management ◽  
Negative Impact ◽  
Demographic Data ◽  
Management Plan ◽  
Adult Males ◽  
Management Actions ◽  
Retrospective Assessment

The elephant population of South Africa's Addo Elephant National Park increased in number from 11 elephants when the park was created in 1931, to 284 elephants in 1998. We studied management records throughout this period in conjunction with demographic data, enabling retrospective assessment of the long-term impacts of management actions. Problem animal control during the 1930s left no sexually mature bulls in the population for a period of 9 years, hindering the population's initial recovery. Population growth prior to 1954 was also limited by high mortality: between 1931 and 1954 inadequate fencing allowed elephants to stray outside their protected area resulting in elephants being shot by farmers or dying from collisions with trains. Secure elephant-proof fencing was constructed in 1954. Subsequently, there was a significant decrease in mortality (from 5.0% to 1.2%) and an increase in population growth (from 3.2% to 6.1%). However, evidence suggests that confinement might have had a negative impact on survival and social behaviour of adult males. We suggest that the concepts of social carrying capacities and behavioural conservation of populations need to be incorporated into management. The case studies described here highlight the importance of treating conservation management and research as necessary partners, and monitoring should be an integral part of any management plan.

Productivity and survival rate trends in the freshwater spawning and rearing stage of Snake River chinook salmon (Oncorhynchus tshawytscha)

2001 ◽  
Vol 58 (6) ◽  
pp. 1196-1207 ◽  
Author(s):  
C E Petrosky ◽  
H A Schaller ◽  
P Budy
Keyword(s):  
Survival Rate ◽  
Chinook Salmon ◽  
Oncorhynchus Tshawytscha ◽  
Adult Stage ◽  
Life Stage ◽  
Snake River ◽  
Climate Conditions ◽  
Management Actions ◽  
Significant Survival ◽  
Stream Type

Stream-type chinook salmon (Oncorhynchus tshawytscha) populations in the Snake River (northwest United States) have declined dramatically since completion of the federal hydrosystem. Identifying the life stage that is limiting the survival of these stocks is crucial for evaluating the potential of management actions to recover these stocks. We tested the hypothesis that a decrease in productivity and survival rate in the freshwater spawning and rearing (FSR) life stage since completion of the hydropower system could explain the decline observed over the life cycle. The decline of chinook populations following completion of the hydrosystem was not accompanied by major survival changes in the FSR life stage. FSR productivity showed no significant decline, and the FSR survival rate decline was small relative to the overall decline. However, significant survival declines did occur in the smolt-to-adult stage coincident primarily with hydrosystem completion, combined with poorer climate conditions and possibly hatchery effects. Potential improvements in survival that occur only at the FSR life stage are unlikely to offset these impacts and increase survival to a level that ensures the recovery of Snake River stream-type chinook.

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