Assessing vulnerability of listed Mediterranean plants based on population monitoring

Gauthier, Perrine; Pons, Virginie; Fisogni, Alessandro; Murru, Valentina; Berjano, Regina; Dessena, Simone; Maccioni, Anna Maria; Chelo, Chiara; Manincor, Natasha de; Doncieux, Antoine; Papuga, Guillaume; Thompson, John D.

doi:10.1016/j.jnc.2019.125758

Cited by 6 publications

(9 citation statements)

References 39 publications

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“…This last method forced observers to survey the quadrat homogeneously and has been regularly used in the plant survey literature (e.g. Gauthier et al, 2017Gauthier et al, , 2019. For the unlimited and cell counts, observers recorded the time they spent counting in each quadrat.…”

Section: Counting Methodsmentioning

confidence: 99%

“…To assess whether imperfect detection of individuals is indeed the rule in plant counts, we conducted a field experiment in which observers counted plants in 1x1 m quadrats, a commonly used quadrat size (Elzinga et al, 1998;Gauthier et al, 2017Gauthier et al, , 2019. The experiment covered 30 species and 300 quadrats, and involved 158 observers who made 5,024 counts.…”

Section: Introductionmentioning

confidence: 99%

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Plants stand still but hide: imperfect and heterogeneous detection is the rule when counting plants

Perret

Besnard

Charpentier

et al. 2022

Preprint

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1. The estimation of population size and its variation largely relies on counts of individuals, generally carried out within spatial units such as quadrats or sites. Missing individuals during counting (i.e. imperfect detection) results in biased estimates of population size and trends. Imperfect detection has been shown to be the rule in animal studies, and most studies now correct for this bias by estimating detection probability. Yet this correction remains exceptional in plant studies, suggesting that most plant ecologists implicitly assume that all individuals are always detected. 2. To assess if this assumption is valid, we conducted a field experiment to estimate individual detection probability in plant counts conducted in 1x1 m quadrats. We selected 30 herbaceous plant species along a gradient of conspicuousness at 24 sites along a gradient of habitat closure, and asked groups of observers to count individuals in 10 quadrats using three counting methods requiring progressively increasing times to complete (quick count, unlimited count and cell count). In total, 158 participants took part in the experiment, allowing an analysis of the results of 5,024 counts. 3. Over all field sessions, no observer succeeded in detecting all the individuals in the 10 quadrats. The mean detection rate was 0.44 (ranging from 0.11 to 0.82) for the quick count, 0.59 for the unlimited count (range 0.18–0.87) and 0.74 for the cell count (range 0.46–0.94). 4. Detection probability increased with the conspicuousness of the target species and decreased with the density of individuals and habitat closure. The observer′s experience in botany had little effect on detection probability, whereas detection was strongly affected by the time observers spent counting. Yet although the more time–consuming methods increased detection probability, none achieved perfect detection, nor did they reduce the effect on detection probability of the variables we measured. 5. Synthesis and applications. Given that plant detection was always imperfect and highly heterogeneous, rather than rely on raw counts, plant ecologists should use methods that estimate the detection probability of individuals to assess the size, temporal or spatial trends of plant populations.

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Section: Counting Methodsmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

Plants stand still but hide: imperfect and heterogeneous detection is the rule when counting plants

Perret

Besnard

Charpentier

et al. 2022

Preprint

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“…Demographic studies on Mediterranean coastal plants are still lacking and only a few studies have examined endemic and/or threatened plants (e.g. Iriondo et al 2009;Cursach and Rita 2014;Pisanu et al 2012;Sulis et al 2018;Belaid et al 2018;Marrero et al 2019;Cogoni et al 2019;Gauthier et al 2019;Orsenigo et al 2020), and even more scarce are the analyses at the population level. In fact, to our knowledge, despite the key role in conservation programs, demographic data and analyses are scarce, even for those plant species for which these activities are mandatory by international or national regulations, with a few exceptions (e.g.…”

Section: Discussionmentioning

confidence: 99%

“…Médail and Quézel 1997;Nikolić et al 2008;Bacchetta et al 2012;Iliadou et al 2014), demographic studies on endemic and/or threatened plant populations are uncommon, even more so at the local level (e.g. Pino et al 2007;Iriondo et al 2009;Pisanu et al 2012;Cursach et al 2013;Cursach and Rita 2014;Belaid et al 2018;Sulis et al 2018;Marrero et al 2019;Gauthier et al 2019;Cogoni et al 2019).…”

Section: Introductionmentioning

confidence: 99%

From global to local scale: where is the best for conservation purpose?

et al. 2020

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Demographic analysis of plant populations represents an essential conservation tool allowing to identify the population trends both at global and at the local level. In this study, the population dynamics of Helianthemum caput-felis (Cistaceae) was investigated at the local level by monitoring six populations distributed in Sardinia, Balearic Islands and Ibero-Levantine coast (Alicante). Demographic data for each population were analysed by performing Integral Projection Models (IPMs). Our results showed that, although the local trend of the main basic demographic functions was similar, vital rates and demographic dynamics varied among populations indicating high variability. In fact, asymptotic growth rate in Spanish populations widely varied both between years and populations (some populations growth, decline or strongly decline), while Sardinian populations showed greater equilibrium or a slight increase. Also, the typical pattern of a long-lived species was not supported by the results at the local scale. These results indicated that different populations of the same species can present extremely different population dynamics and support the belief that, for conservation needs, local studies are more informative than global ones: the conservation status of H. caput-felis could notably vary at a small spatial scale and, accordingly, the conservation efforts must be planned at the population level and supported by local analysis.

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“…Regardless, to be effective, conservation actions for those species require reliable basic information about the distribution ranges, ecological requirements, population numbers, population sizes, and, if possible, demographic patterns (i.e., vital rates) over a defined period of time [ 3 , 13 , 14 , 15 ]. Although demographic analyses have been successfully applied in plant ecology and evolutionary biology [ 16 , 17 , 18 , 19 ], their use in conservation biology remains lacking [ 15 , 20 , 21 , 22 , 23 , 24 ]; this is especially true in the Mediterranean Basin, where in-depth demographic studies on endemic and threatened plant populations are uncommon [ 7 , 15 , 20 , 25 , 26 , 27 , 28 ]. This lack of knowledge is even more relevant in the case of plants that have been neglected, recently described, or have typical or exclusive dynamic or peculiar habitats, such as ecotones.…”

Section: Introductionmentioning

confidence: 99%

Persistence of the Strictly Endemic Plants of Forest Margins: The Case of Cirsium alpis-lunae in the Northern Apennines (Italy)

Fenu

Lazzaro

Lastrucci

et al. 2022

Plants

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Narrow endemic plants constitute a pivotal group for conservation, being often reduced to a small contingent of individuals and frequently threatened. However, effective conservation actions require reliable basic information about distribution range, ecological requirements, and population traits. Nevertheless, such knowledge results are incomplete or even completely missing for some neglected or recently described plants, such as Cirsium alpis-lunae, a thistle exclusive to the N-Apennines (Italy). To fill this gap, all sites where C. alpis-lunae grow were monitored, and data on the site and population traits were collected. Our results indicated that this plant is restricted to 16 scattered sites, varied in surface area and number of individuals. Reproductive and juvenile plants showed to be affected by roughly the same variables, in particular the surface of the site, the slope aspect, and the canopy cover. The narrow ecological niche of C. alpis-lunae was mainly determined by the canopy cover, and where coverage increases, the number of individuals decreases. The individuals only grow at forest edges, where the peculiar ecological conditions are limiting factors for the development of forestry cover; some other factors (i.e., high inclination and instability of the substrate) contribute to limiting the development of forestry vegetation and guarantee the persistence of these ecotones. Despite the great difficulties in accessing the sites where this species grows, this study presents, for the first time, a complete picture of the C. alpis-lunae population and yielded important data to identify effective conservation measures.

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Assessing vulnerability of listed Mediterranean plants based on population monitoring

Cited by 6 publications

References 39 publications

Plants stand still but hide: imperfect and heterogeneous detection is the rule when counting plants

Plants stand still but hide: imperfect and heterogeneous detection is the rule when counting plants

From global to local scale: where is the best for conservation purpose?

Persistence of the Strictly Endemic Plants of Forest Margins: The Case of Cirsium alpis-lunae in the Northern Apennines (Italy)

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