Distribution and breeding of the slender-billed gull Chroicocephalus genei, common tern Sterna hirundo and little tern Sternula albifrons in Algeria

We applied two recent approaches largely used in biological conservation: Threat Analysis (TAN) and Threat Reduction Assessments (TRAs), assessing the effectiveness of a project focused on two water-related bird species (common tern, Sterna hirundo and little tern, Sternula albifrons), commonly breeding in some wetlands of Italy. We used the IUCN standardized lexicon for the classification of threats, utilizing a panel of experts to assess a set of regime attributes (extent, severity and magnitude) of each human-induced disturbance. Our aims were: (i) through the TAN approach, to carry out an arrangement and quantification of the main threats acting on our focal species and select the priority ones; (ii) through the TRA approach, to test the effectiveness of an operational project focused on mitigating the threats and improving the breeding success of species (i.e., building rafts and floating islands to encourage their nesting). Using the TAN approach, experts identified the following human-induced threats (IUCN code): 6.1—Generic disturbance; 7.2—Water stress; 7.3—Salinization; 8.8—Vagrant dogs; 8.8—Mediterranean gulls; 8.8—Wild boars, all significantly different in their magnitude. Among them, wild boars and Mediterranean gulls appeared the priority threats with the greatest extent, intensity and magnitude. Using the TRA approach, after the project, we assessed an overall decrease in the threat magnitude of 23.08% (21.42% when considering only the threats directly affected by our project). These data suggest that further efforts should be devoted to achieving greater effectiveness of conservation actions focused on our target species. With limited time and resources to quantify threats, expert-based approaches could be useful for rapidly assessing the effectiveness of small conservation projects by providing a range of scores obtained following an analytical procedure. In this regard, Threat Analysis and Threat Reduction Assessment could be considered useful tools to support adaptive management in project management cycles.

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“…Since these two terns show a comparable nesting ecology [28], we considered both as a single conservation unit.…”

Section: Study Areamentioning

confidence: 99%

Evaluating the Effectiveness of a Conservation Project on Two Threatened Birds: Applying Expert-Based Threat Analysis and Threat Reduction Assessment in a Mediterranean Wetland

Giovacchini

Battisti²,

Marsili

2022

Diversity

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Some Population Aspects of Common Tern Sterna hirundo Breeding in Algeria at a Small Mediterranean Island (East Coast of Algeria)

Khemis

Boutabia²,

Farhi

et al. 2021

Ekológia (Bratislava)

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We present the first detailed study of population dynamics, breeding biology and egg measurement of Common Terns. During six years (from 2004 to 2009) of monitoring, from mid-May to mid-August, 74 Common Terns individual were recorded at Laouinet small island, El Tarf, northeast of Algeria, witha finite population growth rate that indicated an alarming population decline(λ = -0.62: Lambda). Sterna hirundo build its nests (n = 37) in the northeast at a mean distance of 7.58 m from the closest edge of rocks. The nests were closed and ovoid, constituted mainly of mussel shells Sandpit, stems and leaves. Incubation was performed by pairs of common tern and lasted 25.5 ±3.4 days. We recorded a clutch size of 1 to 3 eggs with mean clutch size of 2.45±0.65 (41.24±0.83 × 30.46±0.62 mm). The egg parameters (volume, mass, shape index) varied between the six years of the study. The egg volume (19.24±0.87) depended more on egg width (30.46±0.62), however the egg shape (0.73±0.20) depended negatively on the egg length (41.24±0.83) but not on the egg width. Our results also showed a stabilized hatching success and a best estimation of breeding success. The hatching success did not vary between years: 70.5% in 2004, 68.75% in 2005, 71.42% in 2006, 71.42% in 2007, 69.23% in 2008 and 69.23% in 2009.

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Distribution and breeding of the slender-billed gull Chroicocephalus genei, common tern Sterna hirundo and little tern Sternula albifrons in Algeria

Cited by 2 publications

References 42 publications

Evaluating the Effectiveness of a Conservation Project on Two Threatened Birds: Applying Expert-Based Threat Analysis and Threat Reduction Assessment in a Mediterranean Wetland

Evaluating the Effectiveness of a Conservation Project on Two Threatened Birds: Applying Expert-Based Threat Analysis and Threat Reduction Assessment in a Mediterranean Wetland

Some Population Aspects of Common Tern Sterna hirundo Breeding in Algeria at a Small Mediterranean Island (East Coast of Algeria)

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