Source and sink dynamics of density-dependent otter (Lutra lutra) populations in rivers of central Finland

Sulkava, Risto; Sulkava, Pekka; Sulkava, Pertti

doi:10.1007/s00442-007-0774-3

Cited by 25 publications

(16 citation statements)

References 22 publications

(26 reference statements)

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“…Individuals in a sink habitat have on average lower reproductive value: their expected contribution to the future gene pool is smaller than that in a source, which renders natural selection in the sink less effective . The sink nature of marginal habitats has been directly demonstrated in a number of species, at various spatial scales (e.g., Blondel et al 2006, Boughton 1999, Breininger & Carter 2003, Manier & Arnold 2005, Stanton & Galen 1997, Sulkava et al 2007, Thingstad et al 2006. The lines show the local population growth (births minus deaths) as a function of local density for a high-quality core habitat (red) and a marginal habitat (blue); the asterisks indicate equilibria.…”

Section: Demography Of Marginal Populationsmentioning

confidence: 99%

Adaptation to Marginal Habitats

Kawecki

2008

Annu. Rev. Ecol. Evol. Syst.

530

643

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■ Abstract The ability to adapt to marginal habitats, in which survival and reproduction are initially poor, plays a crucial role in the evolution of ecological niches and species ranges. Adaptation to marginal habitats may be limited by genetic, developmental, and functional constraints, but also by consequences of demographic characteristics of marginal populations. Marginal populations are often sparse, fragmented, prone to local extinctions, or are demographic sinks subject to high immigration from high quality core habitats. This makes them demographically and genetically dependent on core habitats and prone to gene flow counteracting local selection. Theoretical and empirical research in the past decade has advanced our understanding of conditions that favor adaptation to marginal habitats despite those limitations. This review is an attempt at synthesis of those developments and of the emerging conceptual framework.

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Section: Demography Of Marginal Populationsmentioning

confidence: 99%

Adaptation to Marginal Habitats

Kawecki

2008

Annu. Rev. Ecol. Evol. Syst.

530

643

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“…The spread was rather driven by the overall increase in species range and numbers in Poland (Romanowski 2006), simultaneous to the process in many other European countries (Elmeros et al 2006; Sulkava et al 2007; Clavero et al 2010). According to our observations during consecutive field surveys, no significant positive changes in riparian habitats in Bzura catchment were observed since 1990s.…”

Section: Discussionmentioning

confidence: 99%

“…Carrying capacity of otter habitats in a large distribution range may differ in particular areas, and the high-quality habitat patches are usually sites of source populations for the surrounding areas of lower quality (Sulkava et al 2007). The recolonized Bzura catchment offers lower-quality habitats as compared to many other Polish rivers.…”

Section: Discussionmentioning

confidence: 99%

“…Very small rivers can be used as feeding grounds or migratory routes; however, they cannot sustain sedentary breeding population. Sulkava et al (2007) reported that small river systems were inhabited by otters temporary and abandoned during winter, and that probability of successful breeding in the suboptimal habitats was very low. Summarizing, poor-quality habitats are being visited occasionally by otters, and thus, environmental analysis which attempt to explain otter distribution based on the abundance of otter signs may give a large proportion of unexplained variation (Jenkins and Burrows 1980; Macdonald and Mason 1983).…”

Section: Discussionmentioning

confidence: 99%

“…However, the increase in the populations in their natural range (Sulkava et al 2007) and recolonization processes are recently observed in several European countries (Green and Green 1997; Kranz et al 2001; Mason and Macdonald 2004; Elmeros et al 2006; McDonald et al 2007; Prigioni et al 2007). In the past, decline and/or extermination of otter populations was due to numerous reasons, including water pollution, PCBs concentrations, declining food resources, riparian habitat loss, hunting, poaching, road traffic, and fish trap mortality (Macdonald and Mason 1994; Mason 1989, 1997).…”

Section: Introductionmentioning

confidence: 99%

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Habitat correlates of the Eurasian otter Lutra lutra recolonizing Central Poland

2012

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The increase in Eurasian otter Lutra lutra populations in their natural range and recolonization processes are recently observed in several European countries. We address the process of otter recolonization and habitat utilization in Central Poland over 14 years. Field surveys in 1998 and 2007 documented increase in occurrence of the species. The frequency of positive sites denoted 15 % in 1993, 38 % in 1998, and 89 % in 2007. Otter occurrence at study sites was positively affected by river width while negatively affected by presence of buildings at the site and river regulation. During the most intensive colonization process in the 1990s, the habitat preferences of the otter did not change. However, the sites inhabited by otters after 1998 were characterized by lower river width and tree cover and were more often located on regulated river sections, suggesting change in habitat tolerance during expansion. The otter abundance in transformed habitats is a result of increasing population numbers and the necessity to inhabit suboptimal sections of watercourses. Thus, it seems that presence–absence data for otter populations cannot be considered a reliable indicator of habitat quality, being depended of the population density.

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Variations in reproduction and age structure in the North American river otter in North Carolina, USA

et al. 2023

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Historically, the North American river otter (Lontra canadensis; otter) was distributed across North Carolina, USA, but populations were decimated by the early 1900s. Otter trapping was prohibited in 1938, reopened in 1947, and gradually expanded until it was opened statewide in 2005. Between 1986 and 1992, the North Carolina Wildlife Resources Commission and Great Smoky Mountains National Park released 404 otters to restore populations in western North Carolina. Our objective was to determine if the age structure and reproductive rates of otters throughout North Carolina shifted from 1978 to 2018 between remnant and reintroduced populations. During the 1978–1980 (period 1; Coastal Plain) and the 2009–2013 and 2014–2016 (period 2; statewide) trapping seasons, we collected 1,439 otter carcasses from licensed trappers, fur buyers, and wildlife damage control agents throughout the 3 Furbearer Management Units (FMUs) and 14 river basins in North Carolina. We conducted necropsies, used cementum annuli of the lower canine for age analysis, and counted corpora lutea and fetuses for fecundity estimates. Age distributions for all otters were skewed toward the younger age classes and did not differ between collection periods. During period 1, adults in the Coastal Plain had higher corpora lutea counts than during period 2, whereas Coastal Plain yearlings and juveniles had higher numbers of corpora lutea during period 2. During period 2, corpora lutea counts differed among FMUs; counts in the Mountain FMU (x̄ = 2.56) were higher than in the Coastal Plain FMU (x̄ = 1.62) or the Piedmont FMU (x̄ = 1.91). Within the Coastal Plain FMU and pooling all age classes, fecundity increased by 45% from period 1 to period 2. Adult fecundity in the Coastal Plain FMU declined 16% from period 1 to period 2, while juveniles and yearlings began reproducing between the periods, indicating that reproduction has shifted to younger age classes between 1978 and 2018.

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Source and sink dynamics of density-dependent otter (Lutra lutra) populations in rivers of central Finland

Cited by 25 publications

References 22 publications

Adaptation to Marginal Habitats

Adaptation to Marginal Habitats

Habitat correlates of the Eurasian otter Lutra lutra recolonizing Central Poland

Variations in reproduction and age structure in the North American river otter in North Carolina, USA

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