Assessing range re-expansion and recolonization of human-impacted landscapes by threatened species: a case study of the otter (Lutra lutra) in Italy

Marcelli, Manlio; Fusillo, Romina

doi:10.1007/s10531-009-9618-2

Cited by 30 publications

(63 citation statements)

References 55 publications

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“…First, otter populations in Andalusia were not restricted to a single geographical area within the region in any of the three surveys. Second, the expansion of otter populations has not followed a particular geographical direction (see Marcelli & Fusillo, 2009) (i.e. the size of a hypothetical polygon enclosing otter populations in Andalusia has remained relatively stable across otter surveys, see Fig.…”

Section: Discussionmentioning

confidence: 99%

Natural, human and spatial constraints to expanding populations of otters in the Iberian Peninsula

Clavero

Hermoso

Brotons

et al. 2010

Journal of Biogeography

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Aim To determine the relationships between otter (Lutra lutra) distribution dynamics and environmental and spatial constraints over a 20‐year period. Location Andalusia, southern Iberian Peninsula. Methods We synthesized otter distribution data from three otter surveys (1985, 1995 and 2005) using subcatchment areas defined by hydrological barriers. Subcatchments were characterized by two ‘natural’ (climatic and orographic variables) and two ‘human’ (land use and population density) gradients. In addition, we calculated two contagion variables (the distance to previously occupied subcatchments and the percentage of occupied subcatchments within a 50 km buffer) for consecutively surveyed subcatchments. Results Between 1985 and 2005 the percentage of subcatchments with otters present increased from 42% to 72%. Otters tended to be rare or absent from human‐dominated areas. Anthropogenic gradients were better predictors of otter distribution than natural ones. Human and natural gradients showed strong covariation, but for any value of the natural gradients otters tended to be present in subcatchments with lower human impacts. Colonization of new subcatchments was found to be strongly related to contagion variables and expansion rates were slower than those estimated in other studies. Newly colonized areas tended to be located in areas with intermediate human influence, while repeated absences occurred mainly in areas where human impact was most severe. Main conclusions Our results suggest that recent otter expansion across Andalusia is a reflection of large‐scale improvement in environmental conditions. Otter populations that survived the period of strong and generalized declines appear to be acting as sources from which neighbouring areas are colonized, probably aided by improved water quality and increases in food availability. However, the further expansion of otters into their full original range is likely to be constrained by human‐impacted landscapes.

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Section: Discussionmentioning

confidence: 99%

Natural, human and spatial constraints to expanding populations of otters in the Iberian Peninsula

Clavero

Hermoso

Brotons

et al. 2010

Journal of Biogeography

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“…The Eurasian otter ( Lutra lutra , L., 1758) is a semi‐aquatic mammal species (Carnivora: Mustelidae), which has shown a recent re‐expansion across most European countries (e.g., Marcelli & Fusillo, 2009; Clavero et al. , 2010), after a sharp contraction of range distribution from the 1950s to the 1980s.…”

Section: Introductionmentioning

confidence: 99%

“…Barbosa et al. , 2001; Robitaille & Laurence, 2002; Marcelli & Fusillo, 2009; Clavero et al. , 2010).…”

Section: Introductionmentioning

confidence: 99%

Land use drivers of species re‐expansion: inferring colonization dynamics in Eurasian otters

Marcelli¹,

Poledník²,

Poledníková³

et al. 2012

Diversity and Distributions

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Aim Land use intensity has been recognized as one of the major determinants of native species declines. The re‐expansion of species previously constrained by habitat degradation has been rarely investigated. Here, we use site occupancy models incorporating imperfect detection to identify the land use drivers of the re‐expansion of the Eurasian otter (Lutra lutra). Location Czech Republic. Methods We applied multi‐season occupancy models to otter presence–non‐detection data collected in three national surveys (1992, 2000, 2006) at 552 sites (11.2 × 12 km grid cells). Model parameters included site occupancy, colonization and extinction probabilities, and detection probability at a sub‐site level. We modelled changes in occupancy over time as a function of agricultural, urban and industrial land use and change in the extent of agricultural land use. Results Under the best fitting model, occupancy was estimated to be 34.6% in 1992, 51.3% in 2000 and 83.7% in 2006. Detection probability was neither perfect nor constant. Occupancy probability in 1992 was negatively related to land use gradients. Colonization was more likely to occur where a reduction in agricultural land was larger. Variation in extinction and colonization rates along land use gradients resulted in increased occupancy in industrial and especially urban landscapes. Conversely, occupancy remained almost unchanged along agricultural gradients. Main conclusions Dynamics of otter expansion were strongly associated with the two main patterns of the rapid environmental transition that has taken place in the Czech Republic since the early 1990s. Results show that a reduction in intensive agricultural land use led to an increase in otter distribution, providing evidence of the impact of agricultural land use on stream ecosystems. Moreover, otters recolonized urban and industrial landscapes, probably as a result of extensive reduction in water pollution from point sources. Our results suggest that active conservation of otter populations should focus on restoration of freshwater habitat at large scales, especially in agricultural landscapes.

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“…in France (Janssens et al. 2008), Sweden (Björklund and Arrendal 2008), Italy (Marcelli and Fusillo 2009) or Denmark (Elmeros et al. 2006) – or by means of reintroduction as in the Netherlands (Koelewijn et al.…”

Section: Introductionmentioning

confidence: 99%

Genetic structure of Eurasian otter (Lutra lutra, Carnivora: Mustelidae) populations from the western Baltic sea region and its implications for the recolonization of north-western Germany

Honnen¹,

Petersen²,

Kaßler³

et al. 2010

Journal of Zoological Systematics and Evolutionary Research

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We analysed 229 Eurasian otters from eastern and north-western Germany, Denmark and southern Sweden based on sequences of the mtDNA control region and genotypes at 12 polymorphic nuclear microsatellite loci. The main focus of the study lay on the north-west German otters from Schleswig-Holstein, which represent a newly established and expanding population recolonizing a formerly inhabited region, thereby closing the distributional gap between the large eastern population and the long-isolated and genetically depleted Danish population. As found before in this species, mtDNA variability was very low but we identified a hitherto unknown haplotype in Sweden. Expected heterozygosities were between 0.46 and 0.69 and thus within the range known from the literature. There were only weak signs of a founder effect in the Schleswig-Holstein otters with respect to allelic diversity (but not heterozygosity). Nevertheless, there was a statistically significant bottleneck signal based on deviations from mutation-drift equilibrium in Schleswig-Holstein. All statistical approaches (amovas, factorial correspondence analysis, assignment tests and Bayesian structure analysis) unequivocally showed that north-western Germany has so far been predominantly recolonized by otters of east German origin, but we also found evidence of admixture through immigration from Denmark. Both the Danish and the north-west German otter population will benefit from further exchange in the wake of the ongoing range expansion.

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Assessing range re-expansion and recolonization of human-impacted landscapes by threatened species: a case study of the otter (Lutra lutra) in Italy

Cited by 30 publications

References 55 publications

Natural, human and spatial constraints to expanding populations of otters in the Iberian Peninsula

Natural, human and spatial constraints to expanding populations of otters in the Iberian Peninsula

Land use drivers of species re‐expansion: inferring colonization dynamics in Eurasian otters

Genetic structure of Eurasian otter (Lutra lutra, Carnivora: Mustelidae) populations from the western Baltic sea region and its implications for the recolonization of north-western Germany

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