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Ornithology in Spain: a descriptive overview based on doctoral theses read in recent decades

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Abstract

This work summarizes variation over time in the 317 doctoral theses on ornithology defended in Spain between 2000 and 2019 whose abstracts have been published in the section Reviews of doctoral theses in Ornithology in the scientific journal Ardeola. These were analyzed in terms of (i) the relative contribution by each university, (ii) the research topics tackled, (iii) the taxonomic groups studied and (iv) differences in author gender. The number of theses defended annually is around 15, but there is an upward trend. Complutense and Barcelona universities hosted the highest number of theses, followed by the Autonomous University of Madrid and the University of Granada. The most selected topics were conservation and reproduction biology, followed by habitat selection, population dynamics and physiology, while the most studied groups of birds were Passeriformes (and within this order, the Paridae), followed by Charadriiformes and diurnal raptors. The number of PhD theses defended by males is higher than those read by females; both genders, however, show a similar positive upward trend in the number of theses read. Our results are an indication of how trends and subject-matters in ornithological research in Spain have progressed in recent years. Key words: bibliometric analysis, birds, early-career researcher, gender-gap, research topic, PhD dissertation
Revista Catalana d’Ornitologia 37:49-57, 2021DOI: 10.2436/20.8100.01.33
Focus
Ornithology in Spain: a descriptive
overview based on doctoral theses read
in recent decades
Javier Menéndez-Blázquez1* & Andrés Barbosa1
This work summarizes variation over time in the 317 doctoral theses on ornithology defended
in Spain between 2000 and 2019 whose abstracts have been published in the section Reviews
of doctoral theses in Ornithology in the scientific journal Ardeola. These were analyzed in terms
of (i) the relative contribution by each university, (ii) the research topics tackled, (iii) the tax-
onomic groups studied and (iv) differences in author gender. The number of theses defended
annually is around 15, but there is an upward trend. Complutense and Barcelona universities
hosted the highest number of theses, followed by the Autonomous University of Madrid and
the University of Granada. The most selected topics were conservation and reproduction
biology, followed by habitat selection, population dynamics and physiology, while the most
studied groups of birds were Passeriformes (and within this order, the Paridae), followed by
Charadriiformes and diurnal raptors. The number of PhD theses defended by males is higher
than those read by females; both genders, however, show a similar positive upward trend in
the number of theses read. Our results are an indication of how trends and subject-matters in
ornithological research in Spain have progressed in recent years.
Key words: bibliometric analysis, birds, early-career researcher, gender-gap, research topic,
PhD dissertation.
1Dpto. Ecología Evolutiva, Museo Nacional de Ciencias Naturales (CSIC), C/José Gutiérrez
Abascal 2, 28006 Madrid, Spain. Orcid: JMB (0000-0002-1882-7896); AB (0000-0001-8434-
3649).
*Corresponding author: jmenendezblazquez@gmail.com
Received: 17.04.21; Accepted: 24.11.21 / Edited by J. Quesada
Ornithological science has a long and, in recent
years, growing tradition in Spain (Barbosa &
Moreno 2004). It is now possible to study the
changes over time in ornithology using bibliome-
tric methods that analyze information and the
evolution of different aspects of scientific litera-
ture (Powell et al. 2010). Bibliometric analyses
offer a fresh approach to the current state of
knowledge that differ from that provided by
traditional literature reviews (Grant & Booth
2009). This is hugely important in older scien-
tific disciplines such as ornithology that have
longer traditions and in which there is greater
interest. Despite this, few scientific literature
reviews have ever been carried out of Spanish
ornithology (Carrascal & Díaz 1998, Barbosa
& Moreno 2004, Gordo 2014, Díaz et al. 2016,
Morales & Traba 2016) and, of these, only one
has focused on ornithological PhD dissertations,
specifically in the period 1990–1999 (Barbosa
2000a). Although the goals and the research
topics addressed in PhD theses provide a good
overview of the progress of ornithological rese-
arch, no other review of PhD dissertations has
been published in Spain since 2000 (Barbosa
2000a). Moreover, the reviews of PhD disserta-
2000
2001
2002
2003
2004
2005
2006
2007
2008
2009
2010
2011
2012
2013
2014
2015
2016
2017
2018
2019
30
28
26
24
22
20
18
16
14
12
10
8
6
4
2
0
PhD dissertations / Nombre de tesis doctorals
J. Menéndez-Blázquez & A. Barbosa
50
Revista Catalana d’Ornitologia 37:49-57, 2021
tions allow for research topics and species to be
more carefully chosen and the efforts of future
lines of research to be better focused, especially
in the case of early-career researchers (Bautista
& Pantoja 2000).
The aim of this study was to summarize the
variation over time, the relative contribution of
each university, the research topics addressed,
the groups of species studied, and author gender
in PhD theses published in Spain in 2000–2019.
The results are contrasted with those obtained
by Barbosa (2000a), the only previous PhD
dissertation review published in Spain.
Materials and methods
For the bibliometric analysis we gathered in-
formation on theses defended in 2000–2019
whose abstracts have been published in the
section Review of Doctoral Theses in Ornithology
in Ardeola: International Journal of Ornithology in
recent years (Barbosa 2000b, 2001, 2003, Valera
2004, 2005, 2006, 2007, 2008, 2009, 2010, 2011,
2012, 2013, 2014, 2015, 2017, 2018, 2019, 2020,
2021). We analysed the same variables as used
by Barbosa (2000a), namely, (i) the number of
theses defended per year [given that the reviews
of doctoral theses in Ardeola are referred to by
academic course (e.g. 1994/1995; 2009/2010,
etc.), a search for the exact year a thesis was
defended was carried out in different databases:
Teseo© v.4.2, Dialnet© and universities’ reposi-
tories], (ii) the number of theses defended at
each university, (iii) the assignment of research
topics in each previosly used by Barbosa (2000a)
and defined by Bautista & Pantoja (2000), and
(iv) the taxonomic classification (Order) of the
species studied in each thesis (and, if within the
order Passeriformes, which family), and whether
or not it corresponds to an indigenous or non-
native bird group for Spain (Iberian Peninsula
and Canary and Balearic Islands). Finally, (v) we
also analyzed differences in gender in dissertati-
on authorship over the years. All dissertations
were revised by the same person (JM-B) to avoid
biases in categorical classifications.
The Shapiro-Wilk test was used to assess the
Normality of the temporal range (study period
< 50 years). We used descriptive statistics and
a Pearson correlation (as a parametric analysis)
to evaluate trends over time of the variables
mentioned, correlating each of them to the
range-years. We applied a simple linear regres-
sion, Chi-square and an analysis of covariance
tests to evaluate trends and differences in the
author gender-gap. In addition, we carried out
a Kendall rank correlation coefficient to identify
differences between research topic categories,
bird orders and the Passeriforme families studied
in the 90s (Barbosa, 2000a) and in our study pe-
riod as a percentage of each variable in relation
to the total for both periods. We used Cramer’s
V correlation to explore potential associations
Figure 1. Number of PhD dissertations in ornithology defended in Spain with abstracts published in Ardeola
in 2000–2019.
Nombre de tesis doctorals en ornitologia a Espanya recollides a Ardeola entre 2000 i 2019.
40 1990 - 1999 2000 - 2019
37
34
31
28
25
22
19
16
13
10
7
4
1
Alcalá
Alicante
Almería
Aut. Barcelona
Aut. Madrid
Barcelona
Cádiz
Cantabria
Castilla-La Mancha
Complutense
Córdoba
Extremadura
Girona
Granada
Huelva
La Laguna
Las Palmas de Gran Canaria
León
Lleida
Málaga
Miguel Hernández
Murcia
Navarra
Oviedo
Pablo de Olavide
País Vasco
Politécnica de Madrid
Rey Juan Carlos
Salamanca
Santiago de Compostela
Sevilla
Valencia
Valladolid
Vigo
PhD dissertations / Nombre de tesis doctorals
Spanish ornithology through PhD thesis
51
Revista Catalana d’Ornitologia 37:49-57, 2021
between pairs of research topics included to-
gether in the same thesis. All analyses were
performed using the R program version 4.1.1
(R Development Core Team, 2021) with the
visual editor R Studio version 2021.09.0+351
(RStudio Team, 2021). The statistical results are
given as a mean ± SD and the significant level
was set at P < 0.05.
Given that the same study may cover more
than one bird taxonomic classification or
research topic, the sum of the values of these
variables is greater than the number of total
PhD dissertations considered in the bibliometric
analysis.
Results
A total of 317 ornithological PhD dissertations
were defended and had abstracts published in
Ardeola in 2000–2019 in Spain, an average of
15.85 ± 6.29 per year, with a maximum of 27 in
2017 and a minimum of 5 in 2001 (Fig. 1). There
was a growing trend in the number of theses
during the study period (Pearson correlation: r
= 0.693, N = 20, P < 0.001). These PhD dis-
sertations were defended at a total of 34 Spanish
universities (Fig. 2), the Complutense University
of Madrid being the one with the largest number
of theses (40 theses representing 12.62% of the
total), followed by the University of Barcelona
(34, 10.72%), the Autonomous University of
Madrid (28, 8.83%) and the University of Gra-
nada (23, 7.25%).
The most commonly tackled subjects were
Conservation (67, 13.03%) and Reproduction
(66, 12.84%), followed by Habitat selection (63,
12.25%), Feeding (56, 10.89%) and Population
dynamics (52, 10.12%). By contrast, the least
treated topics were Biogeography (4, 0.78%),
Paleontology (2, 0.38%) and Systematics (1,
0.19%) (Fig. 3). There was no significant asso-
ciation between pairs of research topics studied
together (Cramers’s V coefficient: jc < 0.3, P
> 0.05) (Fig. 4).
A total of 25 bird orders were explored in
these PhD dissertations. The Passeriformes
order was the most studied group (37.54% of
all theses) (Fig. 5). Within this order, a total of
30 families were studied, the Paridae being the
family with the most theses (18.33%), followed
by the Corvidae, Muscicapidae and Turdidae,
Figure 2. Number of PhD dissertations defended in Spain with abstracts published in Ardeola in 1990–1999
(for more details, see Barbosa 2000a) and 2000–2019 (this study) by university.
Nombre de tesis doctorals publicades a Ardeola a Espanya entre 19901999 (vegeu més detalls a Barbosa
2000a) i 20002019 (aquest estudi) per universitat.
70 1990 - 1999 2000 - 2019
65
60
55
50
45
40
35
30
25
20
15
10
5
Conservation
Reproduction
Habitat selection
Feeding
Population dynamics
Physiology
Behaviour
Parasitology
Migration
Genetic
Depredation
Morphology
Pollution
Evolution
Biochemistry
Veterinary
Biogeography
Paleontology
Systematic
PhD dissertations / Nombre de tesis doctorals
J. Menéndez-Blázquez & A. Barbosa
52
Revista Catalana d’Ornitologia 37:49-57, 2021
each representing 8.33% of this order (Fig. 6).
In all, 34 PhD theses studied bird communities
without focussing on particular species, families
or orders.
There was a significant difference (χ2 =
14.161, df = 1, P < 0.001) in the number of
theses defended by women (125) and men (197).
In both genders there was a positive growth in
the number of theses defended over the years
− women (r = 0.728, N = 20, P < 0.001) and
men (r = 0.434, N = 20, P = 0.056)− but there
was no significant difference (ANCOVA: F1.1 =
1.468, P = 0.233) in the growth trend between
the two genders (Fig. 7).
The total number of PhD dissertations rep-
resents an increase of 240.86% over the total
registered by the end of the 1990s (93 theses;
Barbosa 2000a); there was a significant differ-
ence in the number of theses defended annually
between these two periods [1990–1999, 9.30 ±
4.31 (Barbosa 2000a); 2000–2019, 15.85 ± 6.29;
ANOVA: F1.29 = 8.319, P = 0.007)].
The number of universities hosting PhD
dissertations increased by 61.90%, with 13 new
universities appearing between 2000 and 2019:
Almería, Cantabria, Castilla-La Mancha, Gi-
rona, Huelva, La Laguna, Las Palmas de Gran
Canaria, Lleida, Miguel Hernández, Oviedo,
Pablo de Olavide, Madrid Polytechnic and the
University Rey Juan Carlos (Fig. 2).
Reproduction and Habitat selection remained
in the top three research topics, and was joined
by Conservation, which underwent an increase
of 346.67% during the study period, the largest
increase relative to the number of theses de-
fended in the 1990s (only 15 theses in the 90s,
representing 16.13% studied Conservation) (Fig.
4). Significant differences compared to the 90s
were found regarding the percentage of each
research topic category (Kendall’s coefficient:
t = 0.739; P < 0.001). In total 12 new bird
orders were tackled (an increase of 92.31%),
nine of which are native to the Iberian Peninsula
(Apodiformes, Bucerotiformes, Columbiformes,
Otidiformes, Podicipediformes, Phoenicopteri-
formes, Piciformes, Suliformes and Strigiformes)
and three non-native (Psittaciformes, Sphenisci-
formes and Trochiliformes) (Fig. 4). Within the
Passeriformes, the number of families studied
increased by 150%, with a total of 18 new fam-
ilies studied, of which 10 are native to Spain
(Acrocephalidae, Aegithalidae, Certhiidae,
Cinclidae, Emberizidae, Furnariidae, Laniidae,
Motacillidae, Phylloscopidae and Troglodyti-
Figure 3. Number of PhD dissertations defended in Spain with abstracts published in Ardeola in 1990–1999
(for more details, see Barbosa 2000a) and 2000–2019 by research topic.
Nombre de tesis doctorals a Espanya entre 19901999 (vegeu més detalls a Barbosa 2000a) i 20002019
recollides a Ardeola per tema de recerca.
Behaviour
Biochemistry
Biogeography
Conservation
Depredation
Evolution
Feeding
Genetic
Habitat selection
Migration
Morphology
Paleontology
Parasitology
Physiology
Pollution
Population dynamics
Reproduction
Systematic
Veterinary
Behaviour
Biochemistry
Biogeography
Conservation
Depredation
Evolution
Feeding
Genetic
Habitat selection
Migration
Morphology
Paleontology
Parasitology
Physiology
Pollution
Population dynamics
Reproduction
Systematic
Veterinary
1
0.8
0.6
0.4
0.2
0
-0.2
-0.4
-0.6
-0.8
-1
Spanish ornithology through PhD thesis
53
Revista Catalana d’Ornitologia 37:49-57, 2021
dae) and 8 non-native (Cardinalidae, Icteridae,
Leiothrichidae, Parulidae, Passerellidae, Rhi-
nocryptidae, Tyrannidae and Vireonidae) (Fig.
5). The Rheiformes order was the only family
that was not maintained as a thesis study group
between the two periods. These changes reveal
significant differences in the taxonomic groups
studied between the two periods (Bird order: t
= 0.440; P = 0.004; Passeriforme families: t =
0.597; P < 0.001).
Discussion
Between 2000 and 2019 the number of PhD the-
ses defended in Spain with abstracts published in
Ardeola grew to 317. This trend in the number
of PhD dissertations indicates that the research
effort and interest detected at the beginning of
the 2000s in ornithology in Spain has continued
and even increased (Barbosa 2000a, Barbosa
& Moreno 2004). The increase in the number
of universities and number of theses defended
there, together with the sizeable increase in the
array of orders and families of birds studied, re-
veal a general growth in ornithological research.
However, this growth is not uniform and there
are still great differences in the number of theses
defended in universities. These differences can
be explained by the size, seniority (universities
such as the Universities of Huelva and Almeria
were only founded in 1993, Miguel Hernández
in 1996, Pablo de Olavide in 1996 and Rey Juan
Carlos in 1997), the type of research lines (Bar-
bosa 2000a), and the number of pre-doctoral
researchers or PhD students from non-university
research centers that receive doctoral programs
from each university.
Compared to the 1990s (Barbosa 2000a),
during the study period conservation studies
became the most studied topic in ornithologi-
cal PhD dissertations. This reflects concern in
the scientific community regarding the general
state of conservation of birds and their habitats
in Spain in recent years, which has become one
of main research topics in Spanish ornithol-
ogy (Díaz et al. 2016). In addition, it is worth
highlighting the great growth in topics such a
physiology, parasitology and genetics, probably
associated with the greater accessibility and use
of new technologies in recent decades that has
led to marked differences compared to the 1990s.
Although there were some differences be-
tween the two periods regarding the most studied
bird taxonomic groups, the Passeriformes, Cha-
radriiformes and the two orders of diurnal raptors
(Accipitriformes and Falconiformes) continue
to be the most studied taxonomic groups. In
addition, the Paridae remain the most studied
Passeriforme family. Wide-ranging differences
continue to exist between the research efforts
devoted to certain groups of birds, possibly due
to factors such as the number of species that
each order group contains (Barbosa 2000a),
the interest of researchers in certain species
(i.e., emblematic species, species in decline or
species with long-term ongoing studies), and/
or the characteristics of species including their
breeding systems, population size and their
ease of observation, capture and management.
These factors all affect field sampling and data
recording in the short term, and can facilitate
the work of researchers and increase productivity
and the frequency of publication (Thomas et al.
2003, Barbosa & Moreno 2004).
However, we also found a large increase in
the number of both native and non-native tax-
onomic groups studied in PhD theses defended
in Spain. This may mean that the main lines
Figure 4. Correlation matrix based on Cramer’s V co-
ecient as a measure of association between pairs of
research topics studied in these theses with abstracts
published in Ardeola in 2000–2019 (φc < 0.3, P > 0.05
for all pairs of associations).
Matriu de correlació basada en el coecient V de Cra-
mer com a mesura d’associació entre parells de temes
d’investigació abordats en conjunt en les mateixes tesis
publicades a Ardeola entre 20002019 (φc < 0.3, P >
0.05 per a tots els parells d’associacions).
120
115
110
40
35
30
25
20
15
10
5
Accipitriformes
Apodiformes
Anseriformes
Bucerotiformes
Charadriiformes
Ciconiiformes
Columbiformes
Coraciiformes
Cuculiformes
Falconiformes
Galliformes
Gruiformes
Otidiformes
Passeriformes
Pelecaniformes
Podicipediformes
Phoenicopteriformes
Piciformes
Psittaciformes
Procellariiformes
Pteroclidiformes
Rheiformes
Suliformes
Sphenisciformes
Strigiformes
Trochiliformes
1990 - 1999 2000 - 2019
Bird community
PhD dissertations / Nombre de tesis doctorals
J. Menéndez-Blázquez & A. Barbosa
54
Revista Catalana d’Ornitologia 37:49-57, 2021
of research addressed over the years in Spain,
including long-term studies in species already
studied, are being maintained, and, in addition,
that new bird groups and new research lines are
being explored. Research into new taxonomic
groups not present in Spain can be explained
by the increase in international cooperation in
research (Díaz et al. 2016), the growing interest
in certain groups of birds at international lev-
el, e.g. Sphenisciformes (Menéndez-Blázquez
2020), and the need for researchers to find
outside Spain new areas and/or species that have
not been the subject of prior research. It should
be noted that during the study period a large
number of PhD dissertations focused on bird
communities without specifying species. This
increase in the use of bird communities as an
object of study could be linked to the increase
in PhD dissertations focused on conservation.
In total, 52.94% (18) of PhD dissertations that
used bird communities as a study subject fo-
cused on conservation, which can be explained
by the widespread use of these communities as
indicators of changes in and the conservation
of ecosystems in recent years (Canterbury et al.
2000, Padoa-Schioppa et al. 2006, Banks-Leite
et al. 2011, Mekonen 2017).
The differences found in the number of
doctoral theses defended by men and women
reflects the gender inequality present in the
early stages of researchers’ careers in ornithology
(Jähnig et al. 2019), which may be reflected in
subsequent scientific production, as is the case
in zoology and ecology (Yarwood et al. 2014,
Salerno et al. 2019). Despite these differences,
there is a marked upward trend in the number
of women completing doctoral theses, similar
to the trend for women to be named as lead
authors in ornithological publications (Yarwood
et al. 2014, Salerno et al. 2019). This highlights
the importance of continuing to undertake this
kind of review in Spain and in other countries.
These reviews clarify the causes of widespread
gender differences (Lerman et al. 2021), which
will help minimize this gender gap in the future
and make ornithology −and all other scientific
disciplines− an egalitarian science in terms of
authorship and scientific output at different
stages in researchers’ careers.
The search method used in this study may
have certain biases that need to be taken into
account when interpreting the results (especially
regarding data with few records such as universi-
ties or bird taxonomic groups). We took into ac-
Figure 5. Number of PhD dissertations defended in Spain with abstracts published in Ardeola (for more details,
see Barbosa 2000a) in 1990–1999 and 2000–2019 by bird order or focused on bird communities.
Nombre de tesis doctorals a Espanya entre 19901999 (vegeu més detalls a Barbosa 2000a) i 2000-2019 re-
collides a Ardeola per ordre d’ocells i centrades en comunitats d’ocells com a objecte d’estudi.
27
31
33
25
23
21
19
17
15
13
11
9
7
5
3
1
Alaudidae
Acrocephalidae
Aegithalidae
Cardinalidae
Certhiidae
Cinclidae
Corvidae
Emberizidae
Fringilidae
Furnariidae
Hirundinidae
Icteridae
Laniidae
Leiothrichidae
Moracillidae
Muscicapidae
Paridae
Parulidae
Passeridae
Passerellidae
Phylloscopidae
Rhinocryptidae
Sittidae
Sturnidae
Sylviidae
Timaliidae
Tyrannidae
Troglodytidae
Turdidae
Vireonidae
1990 - 1999 2000 - 2019
PhD dissertations / Nombre de tesis doctorals
Spanish ornithology through PhD thesis
55
Revista Catalana d’Ornitologia 37:49-57, 2021
count all PhD dissertations whose abstracts have
been published in the section Review of Doctoral
Theses in Ornithology in Ardeola: International
Journal of Ornithology, which a priori represents
a sample of the total number of theses defended
in Spain. This may be caused by possible biases
arising from the process and effort of screening
the PhD theses published in the section by its
editors: A public request is made and together a
more personally invitation to a PhD candidates
and directors to report on the theses they have
recently read or supervised, and to they can
spread the word about the section in Ardeola
for new potential theses review. The effort
to highlight the doctoral theses that are read
differs from one year to another and its success
may be biased by the editor’s contacts (Valera,
pers. comm.). In addition, the acceptance of
the way reviews are submitted to the section by
PhD thesis supervisors as part of their outreach
policy and work should be taken into account
given the lack of awareness of this section in
Ardeola, both by junior and senior researchers.
Nonetheless, the search by editor for abstracts of
theses in the aforementioned section in Ardeola
also involved a search of Teseo© −a database of
all PhD dissertations defended in Spain (Bar-
bosa, 2000a; Varela, pers. comm.)– and so the
sample gathered in this section of the journal
can be taken as a reliable representation of the
total number of doctoral theses in ornithology
defended in Spain.
In this review we have attempted to show
the current state of and the changes occurring
in ornithological PhD dissertations read in
2000–2019 in Spain. The use of this type of
bibliometric analysis of scientific publications de-
rived from PhD dissertations allows for a detailed
vision of these trends and their contribution to
ornithological knowledge. This study transcends
the mere historical vision of PhD dissertations
and provides an overview of the trends and the
general interests pursued by ornithologists, as
well as sociological factors involved (e.g., the
gender-gap).
Acknowledgments
We would like to thank Ciaran Stordy for proofreading
this English version. Agrair també a Gisela Marín-
Capuz la revisió del text en català. We are also grateful
to Raül Aymí for his work during the evaluation and
submission of the manuscript, and are indebted to
Javier Quesada (editor), Francesc Uribe and Francisco
Varela (reviewers) for their advice and comments that
improved the quality of this study. Thanks are also due
to all those who have contributed over the past three
decades to the thesis abstract section in the Review of
Figure 6. Number of PhD dissertations defended in Spain with abstracts published in Ardeola in 1990–1999 (for
more details, see Barbosa 2000a) and 2000–2019 by families belonging to the order Passeriformes.
Nombre de tesis doctorals a Espanya entre 1990–1999 (vegeu més detalls a Barbosa 2000a) i 20002019
recollides a Ardeola per família dins l’ordre dels Passeriformes.
PhD dissertations / Nombre de tesis doctorals
20
18
16
14
12
10
8
6
4
2
0
2000
2002
2004
2006
2008
2010
2012
2014
2016
2018
J. Menéndez-Blázquez & A. Barbosa
56
Revista Catalana d’Ornitologia 37:49-57, 2021
Doctoral Theses in Ornithology in Ardeola (as well as to
its editor) that enabled this work to be undertaken. This
study was conducted with no public or private funding.
Resum
L’ornitologia a Espanya: una imatge
descriptiva a través de les tesis doctorals
llegides en les darreres dècades
Aquest treball resumeix la variació temporal de les 317
tesis doctorals sobre ornitologia defensades a Espanya i
publicades en la secció Ressenyes de tesis doctorals en Or-
nitologia a Ardeola entre els anys 2000 i 2019, així como
la contribució relativa de cada universitat, els temes
d’investigació abordats, els grups d’espècies estudiades
i les diferències en el gènere dels autors. El nombre de
tesis defensades a l’any oscil·la entorn de 15 amb una
tendència a l’alça. La Universitat Complutense i la
Universitat de Barcelona van ser les que van albergar
el major nombre de tesis, seguides per l’Autònoma de
Madrid i la Universitat de Granada. La temàtica més
abordada va ser la conservació i la biologia de la repro-
ducció, seguit per la selecció d’hàbitat, la dinàmica de
poblacions i la fisiologia. El grup d’ocells més estudiat
van ser els Passeriformes (i dins d’ells els pàrids), seguit
dels Caradriformes i les rapinyaires diürnes. El nombre
de tesis doctorals defensades per homes és més gran
respecte a les dones, presentant ambdós gèneres una
tendència positiva similar en la producció de tesis.
Els resultats obtinguts representen una aproximació
del desenvolupament, tendències i interessos de la
investigació ornitològica a Espanya en els últims anys.
Resumen
La ornitología en España: una imagen
descriptiva a través de las tesis
doctorales leídas en las últimas décadas
Este trabajo resume la variación temporal de las
317 tesis doctorales sobre ornitología defendidas en
España entre los años 2000 y 2019 y recogidas en la
sección Reseñas de tesis doctorales en Ornitología en
Ardeola, así como la contribución relativa de cada
universidad, los temas de investigación abordados,
los grupos de especies estudiadas y las diferencias en
el género de los autores de las mismas. El número de
tesis defendidas al año oscila en torno a 15 con una
tendencia al alza. La Universidad Complutense y la
Universidad de Barcelona fueron las que se leyó un
mayor número de tesis, seguidas por la Autónoma de
Madrid y la Universidad de Granada. Las temáticas
más abordadas fueron conservación y biología de la
reproducción, seguidas por la selección de hábitat, la
dinámica de poblaciones y la fisiología. El grupo de
aves más estudiado fueron los Paseriformes (y dentro
de ellos los páridos), seguido de los Charadriformes y
las rapaces diurnas. El número de tesis doctorales de-
fendidas por hombres es mayor respecto a las mujeres,
presentando ambos géneros una tendencia positiva
similar en la producción de tesis. Los resultados ob-
tenidos representan una aproximación del desarrollo,
tendencias e intereses de la investigación ornitológica
en España en los últimos años.
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Supplementary material
The complete list of PhD dissertations from
1990–2019 whose abstracts have been publis-
hed in Ardeola can be found at https://doi.
org/10.6084/m9.figshare.16944913.v1
... Bibliometric analysis is a suitable tool to evaluate these knowledge gaps (Pritchard, 1969) and provide a new approach to that offered by traditional bibliographic reviews (Grant & Booth, 2009). The application of this discipline in the assessment of herpetological research is scarce, limited to a geographical area (e.g., Brazil: de Paiva Affonso et al., 2015), addressing the gender-gap (Chuliver et al., 2021;Rock et al., 2021) or focused exclusively on a specific taxonomic group (e.g., Campos et al., 2014;Angelini et al., 2020;Marín-Capuz & Menéndez-Blázquez, 2021) or research topic (e.g., habitat conservation: Ficetola, 2015) Previous bibliometric analysis show that PhD dissertations offer a good overview of the main lines of research in universities and academic institutions and, therefore, a good representation of the general interest pursuit by researchers and scientific disciplines (Barbosa, 2000;Ardanuy et al., 2009), and it has been already applied to birds (Barbosa, 2000;Menéndez -Blázquez & Barbosa, 2021) and mammals (Menéndez-Blázquez & Marín-Capuz, unpublished data). The results of PhD dissertation analysis allow a more careful choice of research areas and focal species to address, and to focus the efforts of future lines of research mainly for the earlycareer researchers (Bautista & Pantoja, 2000). ...
... In case this was not enough to obtain the necessary information, we did a quick search within the text of the thesis, looking for the key words of interest (e.g., species; study site). We analysed the same variables used by Barbosa (2000) and Menéndez-Blázquez & Barbosa (2021): number of theses defended per year, number of theses defended in each university; assignment of research topic of each theses within the categories defined by Bautista & Pantoja (2000) ("Atlas and Checklist", "Behaviour", "Biological Conservation and Wildlife Management", "Evolution", "Foraging", "Nutrition and Diet", "Genetics", "Habitat Selection", "Morphology, Biometry and Anatomy", "Paleontology", "Parasites and Diseases", "Physiology and Histology", "Pollution", "Population Dynamics", "Reproduction and Breeding Biology", "Taxonomy and Systematic" and "Veterinary"); and the taxonomic order and family species in which each theses is focused. ...
... The distribution in thesis production among universities broadly coincides with the trend observed for ornithological theses (Menéndez-Blázquez & Barbosa, 2021), being the Complutense, Barcelona and Autonomous University of Madrid those which hosted the higher number of doctoral dissertations in both taxonomic groups. The universities with the highest number of published theses for both taxa are among the best in the field of research in Spain (QS World University Rankings ® , 2021). ...
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This section includes the abstracts of some of the PhD-Dissertations submitted in Spain during the 2019-2020 academic year as well as some others not published in earlier volumes of Ardeola. They are in alphabetical order by University where they were presented and, then, by year and alphabetical order of the author's surname. This section also includes a link to access the full version of the reviewed thesis when available. Esta sección incluye los resúmenes de algunas de las Tesis Doctorales en Ornitología defendidas en España en el curso 2019-2020 junto con otras no recogidas en reseñas anteriores. Se ha seguido una ordenación alfabética por universidades y, dentro de ellas, por año y autor. También se incluye un vínculo que permite acceder a la versión completa de la tesis reseñada en caso de que esté disponible. Informative note: In its section PhD-Dissertations Reviews in Ornithology, Ardeola reports any studies on ornithological issues presented in our country. The section is intended as an updated overview of the latest ornithological research performed mainly in Spain. In spite of the efforts of the editor to compile all the theses, we are aware that the collaboration of researchers (supervisors and doctorates) is needed to give a full view of ornithological research in Spain. we therefore invite the scientific community to report on their results (address: ardeola@seo.org). The Scientific Committee of SEO/BirdLife grants a biannual prize to the best Ph Dissertation included in this section. The prize is awarded in the corresponding Spanish Ornithological Conference. we are looking forward to hearing from you, also as proof of the relevance and quality of ornithological research in Spain. Nota informativa: Ardeola recoge en su sección Reseña de Tesis Doctorales en Ornitología aquellas tesis leídas en nuestro país que estudien temas ornitológicos con el fin de informar sobre las más recientes investigaciones desarrolladas, fundamentalmente en España, en este campo científico. A pesar de los esfuerzos que realizamos para reseñar todas las tesis concluidas, somos conscientes de que un registro completo y actual de las mismas requiere de la colaboración de los investigadores (directores y doctorandos). Por ello invitamos a todos aquellos implicados en la realización de tesis en ornitología a que nos informen de sus resultados (dirección: ardeola@seo.org). El Comité Científico de SEO/BirdLife otorga con carácter bienal un premio a la mejor tesis doctoral reseñada en esta sección, que es entregado en el Congreso Español de Ornitología correspondiente. Esperamos vuestras noticias como buena señal de la pujanza de la investigación ornitológica en nuestro país. Universidad de Alcalá Rohrer Rodríguez, Zoë E-mail: zoerohrer@gmail.com Supervisor: Rebollo de la Torre, S. Breeding cliff-nesting birds at mining sites: management recommendations. [Aves rupícolas reproductoras en los espacios mineros: recomendaciones de manejo.] Key words: bird services, ecological traps, habitat preferences, mining restoration, secondary users. Palabras clave: preferencias de hábitat, restauración minera, servicios de la avifauna, trampas ecológicas, usuarios secundarios. Abstract: To build infrastructures, we rely on the construction sector, which produces aggregates and cement through mining activity. The reconciliation of the extractive activity and conservation of natural values is a crucial issue. Currently, our capacity to return ecosystems affected by mining activities to their original situation is limited. An alternative to restoration is the creation of ecosystems for fauna of conservation concern. Cliff-nesting birds (birds that rely primarily on rocky or sandy walls to breed) colonize human-created environments such as mining sites (quarries and aggregate pits from the cement and aggregate sector). However, mining restoration often fails to consider the cliff-nesting fauna that may have colonized these areas. Furthermore, previous work has failed to address how important these man-made habitats are for the conservation of cliff-nesting birds, and how to manage their presence during the active phases of the mining sites. The aim of this thesis is to study the cliff-nesting bird community at mining sites, and to give management recommendations to enhance biodiversity by improving breeding habitats for cliff-nesting bird species in Mediterranean areas of Spain. we expect mining sites to have the potential of accommodating a varied community of cliff-nesting birds. we studied three aspects to manage these communities: (i) the potential risk of generating trap habitats by excess of predation; (ii) the process of breeding habitat selection and habitat preferences of cliff-nesting birds at different scales; and (iii) the ecological services of cliff-nesting birds that could be applied to restoration. To do this, we carried out a large-scale survey in 2016 and 2017, in 29 mining sites during the breeding season in Spain, to study the abundance, richness and diversity of the cliff-nesting communities. The mining sites were representative of the environmental diversity of the study area. Then, we selected two model species. we studied the Eagle Owl's Bubo bubo presence and diet in mining sites and outlined restoration and management considerations for cliff-nesting birds to avoid excess predation pressure. we selected the Sand Martin Riparia riparia to analyze the ecology and habitat selection of cliff-nesting species in mining sites, and to established measures to reconcile mining activity with their breeding populations. we also studied the provision of engineer ecosystem services of birds applicable to restoration actions, as a way of improving the local biodiversity of cliff-nesting birds, by studying the Sand Martin's burrowing activity at mining sites. Our results indicate that mining sites have a varied community of cliff-nesting birds and that, for some species, these sites could be relevant as breeding habitats. we determined that the Eagle Owl is a specialist predator in the mining sites, with rabbits Oryctolagus cuniculus as its main prey, and that their frequent presence in these sites does not generate a risk of excess of predation of the cliff-nesting community. we observed that Sand Martins showed habitat preferences at the different studied scales, and that this information could be used to design management recommendations and restoration actions for this species. Finally, we observed that the burrowing activity of the Sand Martin generated holes that were colonized by secondary cavity-user birds, the Rock Sparrow Petronia petronia being the most abundant species. with this work, we aimed to explore alternatives to conventional restoration actions, to improve vulnerable biodiversity and to reconcile fauna with mining activity. Our study supports incorporating actions to promote cliffs, together with managing the mining sites to form a heterogeneous mosaic of habitats that satisfy the requirements of the cliff-nesting species (roosting, feeding, etc.). Finally, the study of these complementary habitats inside and outside the mining sites should be pursued in future lines of research, to improve the management and conservation of cliff-nesting species in mining sites. Academic year: 2018-2019. Universidad Autónoma de Madrid Alfonso íñiguez, Sergio E-mail: srgalfonso@gmail.com Supervisors: Gil Pérez, D. and Pérez Rodríguez, L. Early bird development modulators: the role of steroids and oxidative stress on ageing. [Moduladores del desarrollo temprano en aves: el papel de los esteroides y del estrés oxidativo sobre el envejecimiento.] Key words: androgens, competition, development, Sturnus unicolor, yolk. Palabras clave: andrógenos, competencia, desarrollo, Sturnus unicolor, yema. Abstract: Life history traits are a set of morphological, physiological or behavioural features or changes that occur through the organism's life and ultimately determine its fitness. The expression of these life history traits is often subject to trade-offs whose resolution promotes the existence of different life history strategies. These trade-offs often involve physiological mechanisms that must be addressed in order to fully understand their origin and evolutionary significance. These mechanisms may include, for instance, the direct effects (and associated costs) of certain hormones or the increased production of reactive oxygen species as a result of some physiological processes, which may constitute a significant cost that constraints the expression of some life history traits. These processes can exert profound effects during early development, when the organism is experiencing a series of fast and deep changes that will ultimately determine its adult phenotype and lifetime fitness. Thus, understanding the effect of early life conditions on key components of individual physiology (e.g. growth rate, oxidative stress levels, rate of cellular ageing) constitutes a central issue in Evolutionary Ecology. In this thesis we experimentally analysed the impact of some components of early life conditions (prenatal and postnatal exposure to androgens, degree of brood competition, impact of oxidative stress) on different relevant physiological traits of the developing individual (growth, oxidative status, physiological stress, immunocompetence, cellular ageing). To do so, we performed a series of experiments under natural conditions using the Spotless Starling Sturnus unicolor as study species. we found that harsh conditions during early development (i.e. increased competition levels via experimental manipulation of brood size) results in impaired nestling growth, particularly among females, which are probably under competitive disadvantage within the broods due to the sexual dimorphism in this species. These conditions also result in increased physiological stress –as reflected by corticosterone levels–, and negatively impacted telomere dynamics, thus reflecting an impact on the rate of cellular ageing during this early period of life. we also found that experimentally increased exposure to androgens (either during prenatal development –via egg injections– or after hatching –via hormone implants–) caused changes in growth trajectories, but exerted no significant effects on immunocompetence or oxidative status. we also found that increased exposure to oxidative stress during early development impairs nestling growth and exerts contrasted effects on different branches of the immune system, stimulating humoral innate immunity and tending to suppress cell-mediated immune responses. The latter effect may suggest an adaptive allocation of resources among components of the immune system that are subject to a trade-off. Finally, we found no support for the widely accepted notion that oxidative stress is the main mechanism explaining individual variability in telomere length. Other processes, like cell proliferation rate, could be relatively more important at least during the characteristic telomere attrition process associated to early development. The last contribution of this thesis is a call for caution when trying to infer oxidative status of individuals by using one or few biomarkers of oxidative stress: despite the magnitude of our experimental induction of oxidative stress via Diquat injections –as revealed by clear effects on individual growth–, this was not captured by two widely used markers of oxidative stress (malondialdehyde concentration and trolox equivalent antioxidant capacity of plasma). This warns against simplistic approaches to oxidative stress responses, and claims for the use of multiple markers of oxidative damage and/or tracking their variations in different tissues. Academic year: 2016-2017. Universidad de Barcelona Cruz Flores, Marta E-mail: martacruzflores@gmail.com Supervisors: Ramos García, R. and González-Solís, J. Life history of a long-lived, migratory species. [Estrategia de vida de una especie longeva y migratoria.] Key words: demography, life history strategies, movement ecology, seabirds, stable isotope analysis. Palabras clave: análisis de isótopos estables, aves marinas, demografía, ecología del movimiento, estrategias vitales. Abstract: Oceans are suffering from rapid environmental change, pointing to the need of multiyear studies on species that can inform us about the strength and direction of these changes. Oceanic environments are remarkably difficult to study, thus studying the Life History (LH) strategy of an oceanic predator may shed new light on the links between the oceanic environment, trophic resources and how these are used for survival, growth, and fecundity. These topics can be studied through different disciplines, such as demography, movement and trophic ecology, for which rapid technological and theoretical advances have opened new avenues of research. The improvements in capture-mark-recapture models, the increasing use of stable isotopes analysis (SIA) in diet and migration studies, together with the size reduction in tracking devices, offer the opportunity to study LH strategies of small species previously inaccessible. with the present thesis, I aimed to study the LH strategy of a small, long-lived, oceanic and migratory species, the Bulwer's Petrel Bulweria bulwerii, in the Atlantic Ocean. Specifically, I aimed to delve into their foraging and migratory strategies and to understand the implications of reproduction on their trophic ecology and survival. Our results revealed that during the breeding period Bulwer's Petrels foraged mainly around the Canarian and Azorean waters to feed on mesopelagic prey. I showed that reproduction implies constraints (at spatial, activity, and trophic levels) and can carry a cost on survival, especially for females, while males seem to reduce this cost through sabbatical years. we evaluated and confirmed the potential of SIA as a good geographic marker to study migratory movements of marine predators. Bulwer's Petrels migrated to two main non-breeding areas, the Central and the South Atlantic, which implied different phenological and migratory strategies. This species showed to be resilient to environment changes during the non-breeding season, but more sensitive to them during the breeding season, resulting in a lower survival in years with higher sea surface temperature. Indeed, we inferred the increasing temperature of the oceans will sharply decrease Bulwer's Petrel survival, compromising their populations viability, and making them an excellent sentinel of the changes occurring in oceanic food webs. Academic year: 2019-2020. Morera Pujol, Virginia E-mail: morera.virginia@gmail.com Supervisors: Ramos García, R. and González-Solís, J. Multi-colony approaches to study migratory and foraging strategies in pelagic seabirds. [Una aproximación multi-colonia al estudio de las estrategias migratorias y de búsqueda de alimento en aves pelágicas.] Key words: animal movement, foraging movements, migration, seabirds, shearwaters. Palabras clave: aves marinas, migración, movimiento animal, movimientos de alimentación, pardelas. Abstract: Movement is a widespread characteristic in the animal kingdom –occurring at many spatiotemporal scales– with consequences at an individual, population, species, and even ecosystem level. It is a very diverse character, with many different drivers that stem from the way in which individuals interact with their environment. Of these, one of the most important is the distribution of resources, particularly for migratory and foraging movements. In migration, the search for an optimal environment involves movement at large spatiotemporal scales, following seasonal changes in resource distribution. In foraging movements, the search for resources happens at small spatiotemporal scales, and involves different strategies to optimise the search and capture of food, including the ability to obtain foraging cues from conspecifics. In seabirds, movement –at large and local scales–has deep repercussions in their life-history traits, evolutionary history, morphology, physiology and behaviour, which makes them a very valuable study group to understand the role, the causes and consequences of migratory and foraging movements in the ecology of marine top-predators. The study of migratory and foraging movements has been revolutionised by the development of smaller, cheaper and better tracking devices, promoting multi-colony, population and even species approaches to the study of animal movement. Yet, it also comes with a set of methodological challenges that have to be addressed in order to make unbiased inferences of space and habitat use at population or species level from individual movement data. In this thesis, we develop methods to test the possible biases introduced by the use of individual tracking data to infer distribution at a population or species level. we then apply these tools to a multi-colony dataset of non-breeding locations of Cory's (Calonectris borealis), Scopoli's (C. diomedea) and Cape Verde (C. edwardsii) Shearwaters, to study their migratory connectivity and non-breeding habitat segregation at the colony, population and species level. Lastly, we apply state-of-the-art spatial models to study foraging distributions of three neighbouring colonies of Cory's Shearwaters, detect the segregation among them and unravel the environmental and behavioural drivers of this segregation. I developed several functions in the R environment aimed at the detection of the effects of individual site fidelity and temporal variability in the inference of spatial use at a colony or population level, and to calculate the degree in which the movements of a single population can be representative of those of the entire species. These tools are applicable to individual movement data regardless of the species or tracking device. we also used these tools to demonstrate the spatial and ecological segregation between the non-breeding distributions of three taxa of Calonectris Shearwaters studied, as well as detecting a stronger degree of migratory connectivity at a population than at a colony level. The later result indicates that individuals of different colonies within a population mix in the non-breeding areas, but birds from different populations do not, which has important implications for their population dynamics and for their conservation and management. Lastly, we demonstrated segregation among the foraging distributions of three neighbouring colonies of Cory's Shearwaters, both in the waters surrounding the colony and in distant, foraging grounds. we found evidence of both environmental and behavioural drivers behind this segregation, and suggest a mechanism through which transfer of information between individuals can be shaping the distributions of foraging seabirds. This thesis provides relevant tools for the field of movement ecology, as they can be used for analysing movements of mobile species, regardless of species, tracking device or spatiotemporal scale. In addition, they are relevant for the field of seabird ecology as they provide insights into the causes of space and habitat use in long-ranging pelagic seabirds. Academic year: 2019-2020. Zajková, Zuzana E-mail: zuzulaz@gmail.com Supervisors: González-Solís, J. and Bartumeus, F. Movement ecology in pelagic seabirds. [Ecología del movimiento en aves marinas.] Key words: at-sea behaviour, bio-logging, geolocation, migration, phenology. Palabras clave: bio-logging, comportamiento animal, fenología, geolocalización, migración. Abstract: Movement is a fundamental component of behaviour and thus both are inextricably linked, so variation in movement patterns usually reflects different behaviours. The way individuals allocate time budgets to different behaviours within circadian rhythms and over the annual cycle will ultimately provide knowledge about evolutionary processes and adaptive capacity, which is also important to proper conservation actions of endangered species. Seabird movements have been studied over the last 20 years with the wide deployment of geolocator-immersion loggers, but wet-dry data seem underused according to literature published. Along four chapters this thesis presents novel insights about movements and behaviour of four little-known seabird species from the Atlantic Ocean: Boyd's Shearwater (Puffinus boydi), Common Tern (Sterna hirundo), Atlantic Petrel (Pterodroma incerta) and Cory's Shearwater (Calonectris borealis). Using wet-dry data alone or combined with positional data we uncovered the timing of major life cycle events and revealed circadian and circa-annual activity patterns of such species. In highly mobile migratory seabirds, the existence of radically different behavioural contexts linked to phenology and the need to exploit different marine environments over the year lead to different behavioural budgets. In the last chapter, we present a new analytical protocol based on state-of-the-art algorithms to decipher behaviours from wet-dry data. we reveal the hierarchical and modular nature of seabird behaviour at an unprecedented level of detail and used cutting-edge data visualization to highlight key insights. Our framework paves the way to use behavioural annotation for addressing old and new questions of interest in ecology from new perspectives using geolocator-immersion sensors. Overall, through this thesis, I highlight the irreplaceable utility of wet-dry data to get unique insights in ecology and behaviour over the annual cycle of seabirds, a difficult-to-observe group of birds that remain out of the human sight most of their life. Geolocatorimmersion sensors continue to be the most extended loggers to track year-round movements of seabirds, since they ensure the welfare of tagged individuals. Therefore, the results compiled in this thesis should encourage researchers to incorporate the use of wet-dry data within hypothesis-driven frameworks, which surely would contribute to increase our knowledge of seabird ecology at sea. Academic year: 2019-2020. Universidad de Extremadura Abad Gómez-Pantoja, José Mª E-mail: abadjm@unex.es Supervisors: Masero Osorio, J.A. and Ville-gas Sánchez, M.A. Ecoimmunology in long-distance migratory birds: metabolic costs and sex-related effects. [Ecoinmunología en aves migratorias de largas distancias: costes metabólicos y efectos ligados al sexo.] Key words: basal metabolic rate, ecoimmunology, habitat, migration, shorebirds. Palabras clave: ecoinmunología, hábitat, limícolas, migración, tasa metabólica basal. Abstract: The immune system is a complex and flexible defence system that evolved to protect animals from invading pathogens and cellular maintenance. It is essential for survival, but also a costly system that competes for resources with other costly activities, generating trade-offs and even reducing host fitness. Thus, the investment in the immune system and the strength of the immune response should be optimized in relation to the surrounding environment, resources available and individual phenotypes to balance their costs and benefits. Charadriiformes is a highly diverse order in terms of ecological strategies, being a good study model to test how different environmental factors may influence the immune system of long-distance migratory birds. This thesis aimed to improve our understanding of the costs of the immune system and the environmental factors that may shape the immune response of migratory waterbirds through the annual cycle. To fulfil this general aim, the following aspects were addressed: (i) the transfer of maternal antibodies is one of the non-genetic strategies by which mothers may influence the development of their offspring. we took blood samples from recently hatched Gull-billed Tern Gelochelidon nilotica chicks, and quantified the concentration of maternal antibodies. Mothers transferred significantly more maternal antibodies to males than to females, and the plasma levels of these antibodies were positively related to early survival of offspring. By this sex-related transference, mothers might favour the survival of males, probably the more sensitive gender, during the early stages of their development. (ii) the activation of the immune system entails potential metabolic costs. we determined the time course of the primary and secondary humoral immune response against sheep red blood cells in non-breeding Little ringed Plovers Charadrius dubius, and estimated the associated energy costs in terms of basal metabolic rate (BMR). The injection with this non-pathogenic antigen elicited the production of specific antibodies that, in both responses, peaked six days post-injection. The plasma levels of antibodies during the secondary response were 29% higher than during the primary response, but the difference was non-significant. BMR did not significantly vary during the primary immune response, but peaked three days post-injection during the secondary response, increasing significantly by 21%. Conversely, plover body mass decreased significantly along the primary immune response, but did not vary along the secondary response, which may point to an energy reallocation strategy during the primary immune response. Interestingly, the BMR peak occurred before the antibody peak, which supports that the activation of the immune response is more costly than the production of specific antibodies. (iii) The increase of salinity is a major concern for coastal and freshwater wetlands that may affect many migratory animals during the non-breeding season. Osmoregulation imposes significant energy costs to organisms, and it may influence physiological traits such as the strength of the immune response. we investigated whether the salinity of African wetlands may induce residual effects that carry over and influence physiological condition in the Black-tailed Godwits Limosa limosa limosa during their northward migration through Europe. Through the analysis of feather stable isotope values, we found that overwintering males and females occupied west African wetlands with a broad salinity gradient, with females using mostly freshwater wetlands. Only in males, salinity of African wetlands was related with differences in the pro-inflammatory immune response to phytohemagglutinin (PHA) and size-corrected body mass of godwits staging in Europe. These findings provide a new perspective onto the processes by which wetland salinity could potentially influence population dynamics through sex-dependent carryover effects, and how migratory species may respond to current and future environmental changes. (iv) Migration may help hosts to reduce the impact and costs associated to pathogens, and this could be especially effective for shorebirds (Charadrii). This waterbird group shows a strong dichotomy in the areas used for breeding and wintering, and while Arctic breeders winter in marine areas, southern breeders tend to use more freshwater areas. These different migratory strategies have been associated with a differential parasite pressure in the environment, being lower in marine habitats, and have led to the hypothesis that shorebird marine species have a lower level of immunocompetence than freshwater species. we tested this hypothesis by comparing the pro-inflammatory response to PHA and its associated energy costs in Dunlins Calidris alpina, a long migratory shorebird breeding in sub-arctic latitudes and wintering mostly, but not exclusively, in marine habitats. we found that the pro-inflammatory response of dunlins overwintering in marine habitats was significantly lower than that of dunlins overwintering in freshwater areas. Associated to this lower pro-inflammatory response, marine dunlins did not vary their BMR and reduced significantly their body mass. Conversely, dunlins from freshwater habitats significantly increased their BMR and did not vary their body mass. These findings support the hypothesis according to which the selection pressures exerted by parasites have a role in the evolution of migration strategies of shorebirds. Academic year: 2018-2019. Universidad de Granada Azcárate García, Manuel E-mail: mazcarategarcia@gmail.com Supervisors: Soler Cruz, J.J. and Ruiz Rodríguez, M.M. Signalling and evolutionary responses to bacterial environments in birds. The case of the Spotless Starling (Sturnus unicolor). [Señalización y respuestas evolutivas a ambientes bacterianos en aves. El caso del estornino negro (Sturnus unicolor).] Key words: animal communication, bacteria, ectoparasitism, nest bacterial environment, sexual signalling. Palabras clave: ambiente bacteriano del nido, bacterias, comunicación animal, ectoparasitismo, señales sexuales. Abstract: Birds are continuously making decisions; the food to eat, the partner to mate, or the host to parasitize. Decision-making has enormous fitness consequences and, at least partially, is modulated by the information received from the environment, including that from clues and signals emitted by other organisms. By definition, the signals function in contexts of social communication and are beneficial for both senders and receivers, while the inadvertently information provided by clues, only benefits to receivers. In both cases, eavesdropping on these cues by undesirable organisms may have significant negative effects on the emitters and, thus, constrain the evolution of related traits. Microorganisms might also play a role in contexts of communication as it has been highlighted in recent years. Bacteria are in continuous interaction with birds, and might, for instance, produce volatile components used in chemical communication. Also, there are many species that inflict severe negative effects to their hosts, including death. Therefore, in a communication context, the evolution of signals and behaviours aimed to reliably showing the ability of individuals to cope with microorganisms will be favoured in host populations. Understanding the evolution of clues and signals, and therefore the selective pressures that may have favoured, maintained, or restricted their development, is essential to understanding the functioning of these traits in particular, and of animal communication in general. The main objectives of the thesis are embodied within the context of information and communication that is sometimes mediated by microorganisms. we mainly worked on different clues and signals of the Spotless Starlings (Sturnus unicolor) that directly or indirectly may be related to microorganisms, in contexts of parasitism, predation and social communication. Specifically, we experimentally studied: (i) the use of visual clues of ectoparasitism by brood parasite females when choosing the host nest to parasitize; (ii) the use of chemical clues by predators and ectoparasites by experimental breaking of faecal sacs of starling nestlings in their nests; (iii) interspecific variation in wear and susceptibility to bacterial degradation of nestling feathers and whether it covaried with nest bacterial environment. Furthermore, in scenarios of sexual selection, we checked: (iv) the relationships between colouration of secondary sexual traits (beak, feathers and legs) and variables related to antimicrobial defences and reproductive success in females; (v) the effects of experimentally shortened starling throat feathers on indicators of phenotypic and genetic quality (the length and dynamics of telomeres), and (vi) the association between two secondary sexual characteristics (length of throat feathers and colour of starling male beak) in a framework of multiple signalling. The main results are that the presence of experimental spots in starling eggshells, simulating those produced by the ectoparasite Carnus hemapterus, affected nest choice by conspecific brood parasitic females. The preferred host nests for brood parasitism were those without clues of ectoparasitism. we also showed that the experimental breakage of faecal sacs increased nest bacterial loads, affected negatively nestlings development, and positively the probability of depredation and, although not significantly, that of ectoparasitism. These results suggest that behaviours associated with parental removal of faecal sacs from nests have evolved, at least partially, to avoid the negative effects of pathogenic bacteria, and to eliminate the chemical clues that facilitate nest detection by predators and ectoparasites. Moreover, when comparing feathers and nest bacterial environment of 16 bird species we detected consistent interspecific differences in nest bacterial loads that covaried with interspecific differences in the susceptibility of feathers to degradation by keratinolytic bacteria, and with feather wear. These results therefore suggest that species-specific bacterial environments determine the integrity of the feathers and their capacity to resist bacterial degradation. This information can be transmitted to conspecifics. Regarding the objectives related to signals functioning in sexual communication contexts, we found that the plasma antimicrobial capacity of females (mediated by natural antibodies), and the amount of uropigial secretion produced, were positively related to their reproductive success, and that those antimicrobial capabilities are related to the coloration of the integuments (feathers, beak and legs). Therefore, these colorations might function as sexually selected signals indicating immune capacity of females during mating. In addition, our results showed negative relationships between the male ornamental throat feathers and telomere length and dynamic one year after manipulation. However, these associations disappeared when considering feather length after the experimental shortening. These results suggest that the detected associations were not due to a direct effect of feather length but to age since older males would have shorter telomeres and longer throat feathers. Finally, experimental feathers shortening produced statistically significant effects on the coloration of the base of the beak the following year. This coloration was positively related to body condition and the natural length of ornamental throat feathers, suggesting a sexual signalling function of this character. These results support, for the first time, a causal link between the expressions of two sexually dimorphic traits, which is essential for understanding their functionality within the multiple signals framework. Altogether, my thesis contributes to the understanding of the evolution of animal communication and signalling in contexts of ectoparasitism, brood parasitism, depredation and social and sexual communication. The originality of some results opens new possibilities and lines of research, such as those highlighting the role of microorganisms in these contexts through experimental approaches. Academic year: 2019-2020. Díaz Lora, Silvia E-mail: silviadiazlora@ugr.es; silvia_monte2@hotmail.com Supervisors: Martín-Vivaldi Martínez, M. and Martínez Bueno, M. Cosmetic colorations and bacteria in contexts of sexual selection in Hoopoes and Hornbills. [Coloraciones cosméticas y bacterias en contextos de selección sexual de abubillas y calaos.] Key words: cosmetic coloration, Hornbills, symbiotic bacteria, Upupa epops, uropygial gland secretion. Palabras clave: bacterias simbiontes, Calaos, coloración cosmética, secreción de la glándula uropigial, Upupa epops. Abstract: Bacteria are common symbionts of macro-organisms frequently establishing mutualistic associations, in which both the symbiont and the host get benefits. One of these benefits is protection of the host against pathogens, by means of defensive substances that the bacteria synthesize. The microbial community associated with the host may be different among individuals of the same species and, consequently, be a property that causes differences in the abilities of those individuals. These differences could be of interest to potential partners and, thus, the production of signals associated with this quality could be under selection. Thus, the quality of an individual's microbiome could be the information transmitted by some existing sexual signals in hosts of beneficial bacteria. The evolution and maintenance of the signals depends on the reliability of the information transmitted. In this scenario, it would be expected the evolution of signals dependent on the symbiotic bacteria hosted, through the colours caused by the metabolites of the bacteria. An example could be the European Hoopoe (Upupa epops). Its uropygial gland secretion harbors bacteria producing antimicrobial substances that are responsible for the brown color of the secretion and of the eggshells, since females actively stain them with the secretion. The fact that the association with bacteria in Hoopoes is temporary and linked to the nest environment raises the question of how they obtain their bacterioma each season. One possibility would be the acquisition of symbionts that may remain in reservoirs in the nests used by other hoopoes the previous years. In such a case, it would be beneficial for the Hoopoes to be able to detect those nests and select them for nesting. The existence of symbionts in the uropygial secretion of birds could be a more widespread phenomenon. In the order Bucerotiformes, a sister clade of Upupiformes formed by 61 species of Hornbills, some species have coloured uropygial secretions, which they use to stain different parts of their body, possibly with an ornamental function. However, it is not known whether their pigmented secretions are linked to the presence of microbial communities in the uropygial gland, as described in hoopoes. In Hornbills and Hoopoes, only females incubate and take care of the nestlings while they are small, and the males provide all the food in that period. Therefore, it is expected that the reproductive investment depends on the quality of their partner. In Hornbills, stained secretions are used by both sexes throughout the year, and therefore they could act as pre-mating signals. However, in the Hoopoes, the colored secretions with bacteria are only present in the females, after pairing, while they are inside the nest, and therefore, they could function as post-mating signals to obtain a greater male investment. The hypothesis of this thesis is that the uropygial glands of Hoopoes and Hornbills harbor communities of symbiotic bacteria differing among individuals, and, that some signal traits have been selected to show their quality. The objectives are to test the following predictions: (i) Hoopoes can incorporate into their gland beneficial bacteria from the material of reused nests, and thus, they would select nests previously used by other Hoopoes; (ii) cosmetic eggshell color in Hoopoes are used by males to infer the quality of females. Therefore, males will make a greater reproductive effort when they are paired with females that have higher quality secretions; (iii) the pigmented uropygial secretions of Hornbills will show evidence of presence of bacteria more frequently than the non-pigmented ones. To test these predictions, we performed an experiment manipulating the presence of material from nests previously used by Hoopoes; and a cross-fostering experiment of clutches between pairs of females in a wild population of Guadix (Spain). The third prediction was tested with bacterial samples taken from 13 species of Hornbills housed in different zoos in Spain, Portugal and France. The Hoopoes preferred nest boxes containing soft material versus empty ones, regardless if the added material came from previously used Hoopoe nests. The characteristics of the experimental material did not affect reproductive success, but they affected bacterial loads of the eggshells and the composition of the bacterial community of the uropygial gland. This is the first time that an effect of the nest material on the uropygial secretion bacteriome is shown in Hoopoes. All the results supported the general hypothesis that in Hoopoes and Hornbills, cosmetic colorations of the uropygial secretion may be selected as quality signals associated with the possession of symbiotic bacterial communities. Male Hoopoes responded to the changes in the eggshells cosmetic color investing less with more saturated color, which is negatively related to the abundance of symbiotic bacteria in the female's secretion. This is the first experimental demonstration of the benefits associated with the female cosmetic signal in Hoopoes. In Hornbills, we confirm for the first time that some species maintain symbiosis with bacteria in their secretions. Contrary to expectations, bacteria were not abundant in colored secretions. However, some of their symbionts may be responsible for the pigmentation of the secretion. In addition, the comparative study of the ornaments of Hornbills shows associations with the presence and abundance of groups of bacteria, both pathogenic and producing defensive substances, and interactions between these bacterial groups. Together, these findings suggest that Hornbills are a new study model of great interest to understand the evolution of mutualistic symbiosis with bacteria in birds, as well as of signals associated with that relationship. Academic year: 2019-2020. Veiga Neto, Jesús E-mail: jveiga@eeza.csic.es; veiga.ew@gmail.com Supervisors: Valera Hernández, F. and Moreno Rueda, G. Determinants of the host-parasite relationship in a system formed by a cavity-nesting bird and its ectoparasites in an arid ecosystem. [Determinantes de la relación parásito-hospedador en un sistema formado por un ave troglodita y sus ectoparásitos en un ecosistema árido.] Key words: arid areas, Carnus hemapterus, ectoparasites, host colonization, host-parasite, vectors. Palabras clave: Carnus hemapterus, colonización del hospedador, ectoparásitos, parásito-hospedador, vectores. Abstract: Parasites are strongly influenced by numerous abiotic and biotic factors operating at different temporal and spatial scales. To understand parasites dynamics, host-parasite interactions and the underlying mechanisms of such interactions it is necessary to study how those factors influence parasites and their relationships with the hosts at the various scales. Here we study the effect of off-host and host-related factors on the relationship between a cavity-nesting bird species, the European Roller (Coracias garrulus) and its ectoparasites, mainly the haematophagous fly Carnus hemapterus. The main factors considered in this study involve habitat characteristics at the mesoscale (the host nest and the immediate surroundings) like nest-site type (a major source of habitat heterogeneity in our study area) as well as host and parasite density, breeding phenology of the host (i.e. seasonal effects) and host total brood mass (as a surrogate of cues for the parasites). we study the effect of these factors on the colonization success and distribution (prevalence and abundance) of the most common ectoparasite (Carnus hemapterus). However, since a given host species usually harbours several parasite species, the approach “one host-one parasite” overlooks the effect of the interactions among parasites that mainly occur at the infracommunity level. Therefore, we also explore the effect of the above-mentioned factors on the ectoparasite infracommunity of the European Roller. Our study is performed in a semi-arid environment, therefore contributing to our knowledge of host-parasite interactions in such habitats that are underrepresented in the scientific literature. Both to fill the gaps on the basic biology of the study species and to build up our study on solid foundations, we also explore basic aspects of the natural history of Carnus hemapterus such as the characteristics of the pupal stage of the ectoparasite or its life span during the dispersal stage (closely related to colonization success). we found that carnid flies have a very short life span during the dispersal stage (less than four days), in spite of which they are able to colonize ca. 100% of the host nests. Its longevity during this period increases with body size, environmental humidity and with access to food (flowers). Nest-site type influences colonization success of carnid flies, so that it is higher in nest boxes on sandstone cliffs-farmhouses than in nest boxes on trees. Colonization success also increased with host density and host brood mass but decreased as the season progressed. Interestingly, parasite density had no effect on host colonization success. Nest-site type also explained differences among nests in composition of the ectoparasite infracommunity and in abundance of various ectoparasite species. These variables were not affected by the spatial structure, nor by brood mass. However, host breeding phenology affects the ectoparasite infracommuity differences in abundance, acting mainly over Carnus hemapterus. Our results also reveal that it is necessary to consider the non-infective stages of parasites when analysing host-parasite relationships since they are important for understanding habitat selection criteria, host-range and processes regulating coexistence with other species. In our study system, the observed patterns of prevalence and abundance of imagoes and pupae of three supposedly generalist ectoparasites (Carnus hemapterus and the louse flies Pseudolynchia canariensis and Ornithophila metallica) suggest that, for some parasite species, the requirements of non-infective stages may be more restrictive than the ones of the parasitic stages. Since some of the ectoparasites here studied are vectors of haemoparasites and since the identification of associations host-vector-pathogens is critical for understanding the ecology of diseases, we studied the likely vectorial role of biting midges (Fam. Ceratopogonidae). we found that Culicoides paolae and C. circumscriptus were common visitors in nests of various species of troglodyte birds. These midges feed on various bird species and harbour four lineages of Haemoproteus. Thus, they can play an important role in the transmission of Haemoproteus in the study area. Finally, this study reveals that the infracommunity of ectoparasites of a cavity-nesting bird species in a semi-arid environment is rich (made up of at least species of eight different families, including a recently introduced species, C. paolae), with some species being particularly abundant. we conclude that socioenvironmental characteristics at small scale are major determinants of the spatial distribution of nest-based ectoparasites in an arid environment. Academic year: 2019-2020. Universidad Pablo de Olavide Baños Villalba, Adrián Supervisors: Edelaar, w. and Tella Escobedo, J.L. Mechanisms of adaptation to a changing world. [Mecanismos de adaptación a un mundo cambiante.] Key words: adaptation to the environment, biodiversity, threatened species. Palabras clave: adaptación al medio, biodiversidad, especies amenazadas. Abstract: The current extinction rate of species on Earth is greater than any of the mass extinctions registered in the fossil record in its entire history. This increased biodiversity loss is caused one way or the other by the human species. Changes in land use, climate or biological invasions are acting worldwide. In this context, understanding the mechanisms by which organisms adapt to the environment and the ecological and evolutionary consequences that these entail is a key factor. In this thesis, this question is approached from two different perspectives. The first one (Section 1) assesses how populations of invasive species adapt to a new environment. Before a population becomes invasive in a non-native area, it must first have passed through the earlier stages of invasion (capture, transport and introduction) before its establishment in this area. These stages could be acting as selective filters of individual variation. In this way, the introduced individuals would not be a random sub-sample of the native population of origin. This could have a great impact on their invasive potential. However, what happens in these earliest invasion stages has hardly ever been studied. To test the hypothesis that selection acts already early during a biological invasion, we followed the individuals of two invasive bird species from their native habitat in Senegal and during these early stages of a potential invasion. we indeed found that selection acts on variation in a gene related to behaviour (Chapter I). In addition, we found that selection also acts on many other phenotypic characteristics that could have a great importance for invasive potential, such as sex, age, body size, brain size, beak size and shape, body condition, stress hormone levels and behaviour (Chapter II). The second perspective (Section 2) assesses how native populations adapt to environmental changes. For this we studied all the possible mechanisms of adaptation (natural selection, phenotypic plasticity, habitat choice and environment adjustment), but especially focusing on matching habitat choice. This mechanism is based on the non-random dispersal of individuals due to an assessment of variation in their local performance, such that individuals settle down in those habitats that best match their phenotypes. Despite its eco-evolutionary importance, this mechanism has received almost no research attention. In this thesis, we study how a native population of grasshoppers has adapted in camouflage (a classic form of adaptation to the environment) in the colonization of a new urban environment (one of the most drastic changes in the habitat). we found a population divergence on a micro-geographic scale (differently coloured grasshoppers on distinctly coloured urban substrates) despite the existence of a lot of (presumably homogenising) movement by individuals. In Chapter III, we demonstrate that habitat choice, and not other mechanisms such as natural selection or phenotypic plasticity, is the main mechanism that has caused the recent local evolution of camouflage and the micro-geographic population divergence. In addition, we found that habitat choice acts also at a much finer scale, in which individuals improve their camouflage by aligning with certain substrate patterns depending on their degree of colour matching with the substrate, making it a flexible way to increase performance on different spatial scales (Chapter IV). However, this matching between phenotype and environment can also be achieved through phenotypic plasticity. In Chapter V we show that grasshoppers are able to change their body coloration through successive moults to resemble the substrate on which they live. The degree to which they do so is affected by the risk of predation they are exposed to: experimental increase of risk resulted in an increased phenotypic adjustment. Taken together, this thesis demonstrates in a convincing and quantitative manner the existence and importance of two neglected mechanisms of adaptation of populations to environmental changes, thereby increasing our understanding of how invasive and native populations adapt to change and ecological opportunities in an increasingly changing world. Academic year: 2017-2018. Álvarez-Blanco, Paloma E-mail: palomaoviedo@hotmail.com Supervisors: Cerdá Sureda, X. and Angulo Aguado, E. Ecosystem responses to the Argentine ant invasion: Effects on vertebrates. [Respuestas del ecosistema ante la invasión de la hormiga argentina: Efectos en vertebrados.] Key words: chemical weapons, invasion ecology hypotheses, Linepithema humile, predator-prey relationships, subtle effects. Palabras clave: armas químicas, efectos sutiles, hipótesis de la ecología de las invasiones, Linepithema humile, relaciones depredador-presa. Abstract: Biological invasions are one of the main drivers of biodiversity loss. Certain effects of invasive species are commonly overlooked and potentially compromise the structure and function of ecosystems in unpredictable ways. This thesis takes advantage of the vast knowledge of the invasive Argentine ant, Linepithema humile, to focus on subtle and indirect effects on the recipient ecosystems, specifically on native vertebrates (amphibians, birds) in Doñana National Park (southern Spain). This tiny intruder is notorious for displacing the native ant community in the ecosystems it has successfully invaded. Therefore, this thesis assesses whether the effects of potential prey depletion scale to higher trophic levels. Although the Argentine ant lacks recognized weapons, it is well known for its aggressiveness when outcompeting native ants. I evaluated whether native vertebrates at their most vulnerable stages are susceptible to being attacked or disturbed by the invasive ant and if they suffer from lethal or sublethal effects that hamper their development. These issues were addressed through field sampling and monitoring, field and laboratory experiments, and analyses of chemical, isotopic, histological, physiological, and behavioural parameters. My results reveal the Argentine ant invasion has negative impacts on native vertebrates in Doñana at different levels. For example, the native amphibians studied here have altered their diet, by shifting to non-ant preys in infested areas. Additionally, vertebrates in their early stages of development showed poor body condition under experimental (juvenile amphibians) and field (chicks) conditions when they were fed a diet supplemented with Argentine ants or raised in invaded areas. Furthermore, both myrmecophagous species, such as the Natter-jack Toad, Epidalea calamita, and non-ant predators, such as the Great Tit, Parus major, modified their habitat use in invaded compared to uninvaded areas, although for different reasons (foraging and breeding, respectively). Finally, I demonstrate, for the first time in the literature, that the invasive Argentine ant has a powerful venom –iridomyrmecin– that is able to paralyze and kill native vertebrates, specifically juvenile amphibians. This unexpected finding deserves special attention, as it may play a key role in the previously demonstrated negative effects/ invasiveness of this species. Overall, this thesis reveals overlooked indirect and subtle effects of an invasive species at different ecosystem levels, but also yields novel information about the mechanisms underlying these effects. Academic year: 2018-2019. Torres Medina, Fernando E-mail: fernantor1@gmail.com Supervisors: Blas García, J. and Marchant, T.A. Stress ecology and adrenocortical function in white Stork (Ciconia ciconia). [Ecología del estrés y función adrenocortical en cigüeña blanca (Ciconia ciconia).] Key words: adrenocortical function, corticosterone, Hypothalamic-Pituitary-Adrenal axis, stress, white stork. Palabras clave: cigüeña blanca, corticosterona, eje Hipotálamo-Pituitaria-Adrenal, estrés, función adrenocortical. Abstract: In birds, the Hypothalamic-Pituitary-Adrenal (HPA) endocrine axis is involved in the secretion of corticosterone, the main stress hormone in this group of vertebrates. Under normal conditions, plasma corticosterone levels fluctuate within a lower range of baseline levels that allows adjusting physiology, morphology and behavior to the predictable energy demands of the environment. In contrast, corticosterone levels typically increase to a higher range of stress-induced levels in response to disturbance, facilitating adaptive changes aimed at maintaining homeostasis while overcoming the perturbation. Repeated or longer-term exposure to disturbance may generate chronic stress, causing deregulation of the HPA axis with imbalanced corticosterone production. This thesis had several major goals. First, I aimed to study the effect of human presence in nature as a potential source of chronic stress in birds. Corticosterone levels were quantified in white Stork (Ciconia ciconia) nestlings exposed to different degrees of human presence and the self-inhibitory mechanism of corticosterone secretion (i.e., negative feedback) was experimentally induced through dexamethasone treatment. Results showed differences in the adrenocortical activity of storks exposed to humans compared to conspecifics living free of anthropogenic presence, as reflected by the lower feather corticosterone levels in the latter group. Such differences were not found when comparing blood corticosterone levels, likely because (contrary to feathers) circulating hormones only reflect short-term physiological trajectories. These results did not provide evidence for chronic stress among human-exposed storks and suggested a reduced exposure to stress events in areas with human presence. As a second goal, I addressed the mechanism responsible for an age-related attenuation in the adrenocortical response to stress typically displayed by altricial birds during post-natal development. Such attenuation of the response to stress has been postulated as an evolutionary mechanism to prevent long-term corticosterone elevations, which may jeopardize growth and development at early ages, when nestlings' physiological and behavioral abilities to cope with disturbances are limited. Two hypotheses have been proposed to explain the mechanism underlying this pattern: (i) a progressive age-related growth and maturation of the HPA axis (Maturation Hypothesis), or (ii) a gradual attenuation in the intensity of the negative feedback in the HPA axis (Negative Feedback Attenuation Hypothesis). This question was addressed by inducing negative feedback through dexamethasone treatment in white Stork nestlings. Results indicated a positive effect of age on plasma corticosterone elevations in response to stress, but no age effects on negative feedback, suggesting that the progressive maturation of HPA axis tissues is the proximal mechanism responsible of the attenuation pattern. The third goal tested the effects of subcutaneous corticosterone implants on adrenocortical function in nestling and adult white Storks. Implants are regularly used in evolutionary and behavioral endocrinology studies to simulate chronic corticosterone elevations (over several days) and study subsequent effects on specific biological traits. Contrary to our predictions, our implant experiments resulted in decreased baseline and stress-induced levels of plasma corticosterone. A review of 50 previously published avian studies revealed that baseline corticosterone levels generally increase (72% of the experiments) while stress-induced levels decrease (78% of the experiments) after implant treatment. The results of this review placed in context our results and contributed to expand the prevailing assumptions in the use of implants because: (i) baseline levels showed a quadratic association with implant dose across bird species (and decreased levels may thus occur at both high and low doses), and (ii) corticosterone implants also decreased stress-induced levels, thus producing stresshyporesponsive phenotypes. This review also revealed important study biases in the use of implants by avian researchers. In summary, this thesis studied the effect of external and internal factors on avian adrenocortical function, examined the proximal mechanisms that allow this function and generated practical knowledge for further research. Academic year: 2018-2019. Gutiérrez Expósito, Carlos E-mail: cgexposito@gmail.com Supervisors: Clavero Pineda, M. and Revilla Sánchez, E. Biology and conservation of the Andalusian Buttonquail (Turnix sylvaticus sylvaticus, Desf. 1789). [Biología y conservación del torillo andaluz (Turnix sylvaticus sylvaticus, Desf. 1789).] Key words: agriculture, conservation biology, refuge, Turnicidae, west Palearctic. Palabras clave: agricultura, biología de la conservación, Paleártico Occidental, refugio, Turnicidae. Abstract: Rise of agriculture during the Mesolithic-Neolithic transition gave birth to a new biotope, the farmland, which in a few thousand years reached a planetary scale at the expense of natural ecosystems. This widespread land use change implied a demise of many avian species as their natural habitats were replaced by crops and grazing lands. However, it became into a new habitat for some grassland birds who were able to shift from their natural habitats to human-made environments. Some avian species found there a land of opportunity, among them a few Buttonquail (Turnicidae) species. However, the recent farmland intensification is leading to a general decline of these species. In this PhD we use the Andalusian Buttonquail (Turnix sylvaticus sylvaticus) as a case study. This species has been able to cope with traditional farming and until recently has had a wide distribution in the western Mediterranean countries but currently is in the verge of extinction. Starting from a global and historical scale approach, contextualizing the taxon at biogeographic and taxonomic levels, we arrive at the “in situ” study of the only population that still survives. In Section 1 we create an index to evaluate the concern status of all Turnicidae species and subspecies by using the BirdLife distribution areas and data from the eBird citizen science platform. we also describe the asymmetric heterochromia in the iris of this family and other pale-eyed bird species as a feature to aid vision by regulating the light entering the eye. In Section 2 we establish the historical evolution of the extinction process in Europe and North Africa, to model and evaluate the historical distribution based on environmental variables and then study the population in Morocco to determine the population size at different times, to evaluate the population trend and to describe habitat selection and reproductive biology. Extinction risk is often associated with species intrinsic traits such as bigger size, higher trophic level, narrower habitat niche or smaller distribution areas. Despite this, fast extinctions can also occur in species apparently not matching any of these traits. Here we describe how this taxon with a former wide range, high reproductive rates, a low trophic level in the food chain, small size and apparently coarse habitat requirements, is close to extinction. By niche modelling we outline its historical distribution and then we explore at a regional scale (Andalusia) the role of historical land use changes and human population trend in the rapid decline of the species. PCA analysis of environmental variables showed that its distribution was mainly determined by low continentality and aridity. Since the 19th century, the decline in the extent of occurrence has been above 99.99%. PCA analysis of land use changes showed that areas with a higher probability of historical presence have suffered more intense agriculture intensification, afforestation processes and higher human population pressure and development. Conservation efforts should focus on maintaining coexistence of the species with the human being. The last populations of threatened taxa usually survive in low-impacted areas, whose protection and management is critical for its conservation. However, they can also be located in humanized and highly dynamic areas, whose management can be extremely challenging. Here, we show how the last Andalusian Buttonquail population is restricted to a small, strongly used agricultural area (4,675ha) in the Atlantic coast of Morocco, where the birds adapt their life cycle to a fast crop rotation. Buttonquails occupy crops during the flowering and fruiting stages, thus changing the preferred crop types along the year, although alfalfa fields were occupied all the year round. we used estimated occupancy rates in different crops to obtain seasonal (2017) and year-to-year population estimates (2011, 2014 and 2017). Numbers showed wide seasonal fluctuations: lowest in winter and maximum in summer (112 to 719 individuals). Year-to-year summer estimates also showed wide variations and large uncertainties, ranging between a maximum 1,890 estimated in 2011 and a minimum in 2014 with 492 individuals. The last population estimate available was 596 individuals in 2017. The area is suffering a rapid shift from traditional irrigation farming towards practices more akin to commercial industrial agriculture. The conservation of this critically endangered taxon is highly dependent on the maintenance of traditional farming practices and a rational on-site agricultural modernization. Understanding the breeding cycle of wildlife is essential to afford conservation strategies. This is especially important for barely studied species and urgent for those in a serious risk of extinction. we performed 2302 sampling events to determine the occurrence and breeding of the species. Breeding season lasted from February to October. The species bred in 17 different crops but it did not use cucumber and artichoke fields. However, a strong selection for alfalfa, pumpkin and maize fields was evidenced. Nests were on average 82mm × 71.4mm grass lined structures built on a ground scrape. Eggs had 26.14mm mean maximum length, 20.24 mean diameter and weighted 5.9g. All complete clutches had four eggs and the hatching rate was 3.42. All monitored nest successfully reared at least one chick. Clutch size and hatching rate matched the standards for other Buttonquail populations and species. Thus, the causes of the decline must be found in other stages of the reproductive cycle. Additional studies are needed to reveal chick and juvenile survival. Academic year: 2019-2020. Universidad del País Vasco / Euskal Herriko Unibertsitatea García Barón, María Isabel E-mail: isa.garciabaron@gmail.com Supervisors: Louzao Arsuaga, M. and Santos Vázquez, M.B. Integrating marine megafauna into ecosystem-based management: a multidisciplinary approach applied to southern European waters. [Integración de la megafauna marina en la gestión a nivel ecosistémico: un enfoque multidisciplinario aplicado a las aguas del sur de Europa.] Key words: ecological modelling, marine megafauna, marine protected areas, oceanographic surveys, systematic conservation planning. Palabras clave: áreas marinas protegidas, campañas oceanográficas, megafauna marina, modelización ecológica, planificación sistemática para la conservación. Abstract: Marine megafauna show high risk of extinction worldwide, raising awareness of the need of priority conservation strategies to ensure their protection. To reverse this situation, information on the spatio-temporal patterns of the pressures that affect the marine environment and an assessment of their severity are urgently needed to inform biodiversity and habitats conservation, devise appropriate mitigation measures and advise spatial planning decision processes. In this context and to anticipate the response of the ecosystems in the face of growing pressures, a holistic management approach, such as the Ecosystem-Based Management (EBM) with an integral vision of the ecosystem is required. Implementing the EBM approach requires multidisciplinary data collection, monitoring of the system state, behaviour, and functioning, development of methods to organize, display, and illustrate the relationships of ecosystem components and methodological developments of transdisciplinary nature to synthesis data, multipurpose and integrative in order to inform management measures. This thesis was focused on the Bay of Biscay (BoB) and the North and North-western Iberian coast where the marine megafauna is suffering increasing disturbances due to anthropogenic pressures and there is evidence of the increasing impacts of climate change. Thus, the main aim of the thesis was to assess the impacts of human activities on marine megafauna by integrating their spatial ecology into EBM. By focusing on seabirds and cetaceans inhabiting the BoB, the thesis developed an integrative ecological framework based on multidisciplinary approaches to identify threats, develop environmental indicators, establish baseline values, obtain estimates of spatio-temporal abundance, assess the coherence of Marine Protected Areas (MPAs) networks and, in addition, examine the value of long-term series for MPA robustness. Firstly, this thesis collected information of the impact of the main threats affecting seabirds and cetaceans in the BoB and developed a two-fold approach to identify the main pressures affecting directly or indirectly cetacean and seabird species. whilst seabirds are particularly sensitive to oil spills, bycatch and marine litter, cetaceans are especially vulnerable to bycatch, vessel collision, and pollution-related threats. This type of assessment studies can aid in the identification of priority areas and/or species where management measures should be applied to ensure that the goal of the Marine Strategy Framework Directive (MSFD), sustainable conservation of the marine environment, is reached. Secondly, an example of the combination of multiple pelagic components was shown to provide an integral assessment to advance EBM by developing a methodological approach to identify biologically appropriate oceanographic and preyscape predictors to jointly consider both the spatial and vertical dimensions of oceanographic habitats. This approach, which can be applied to any marine species, was developed using as case study the Sooty and the Great Shearwaters Ardenna grisea and A. gravis. The species abundance patterns were influenced by oceanographic conditions and prey accessibility integrated above the depth of maximum temperature gradient for Sooty Shearwaters and at the surface for Great Shearwaters, leading to a vertical segregation. Similarly, both species showed a spatial segregation in relation to shelf areas versus oceanic areas. The first abundance estimates for both species during September in the BoB are provided. Thirdly, this thesis identified the Essential Ocean Variables (EOVs) that shape the environmental envelope of the North and North-western Spanish seabird and cetacean's community and delineate their High Value Biodiversity Areas (HVBAs) taking advantage of the sightings collected during annual oceanographic surveys. The sea surface temperature and the chlorophyll-a concentration were identified as EOVs, driving the environmental envelope and shaping the HVBAs. HVBAs were located mainly over the North-western Spanish waters and decreased towards the inner BoB remaining spatially stable over the ten-years study period. The use of this information can facilitate the establishment of baseline values to predict and detect the effect of multiple threats on HVBAs, as well as to fulfil the emergent need for sound spatial information to support the implementation of marine spatial planning. Fourthly, the difficulty of protecting highly mobile species that cross multiple jurisdictional boundaries and multiple non-specific MPAs was addressed by assessing whether the current MPAs network in the area offers protection to the Fin whale Balaenoptera physalus. Results showed that the main critical area for Fin whales was located over the South-Eastern part of the BoB, an area that is currently only marginally covered by three MPAs. Based on these results, a trans-boundary MPA was proposed for this species in the BoB. Finally, the value of time-series data was assessed by exploring whether priority areas for the conservation of megafauna species (i.e. seabirds and cetaceans) remain consistent regardless of the amount of data considered. The results provide a method for calculating the minimum number of monitoring years required to establish an effective MPA network, which we recommend for future spatial prioritization exercises for highly mobile species. All the results obtained in this thesis share a practical goal as they focus on the biodiversity and ecosystem conservation aspects of the EBM, which needs multidisciplinary studies involving different approaches and study techniques. with the aim of operationalising the EBM within the current European legislation, the results intend to integrate new ecosystem components such as marine megafauna into EBM to inform conservation and management measures in the context of the MSFD overall aim, which is to enable sustainable use of marine goods and services. Academic year: 2019-2020. Universidad de Sevilla Luna Fernández, Álvaro E-mail: alvalufer@gmail.com Supervisors: Carrete, M., Sanz Aguilar, A. and Tella Escobedo, J.L. The urbanization process and its effect on the dispersal of birds: the case of the Burrowing Owl (Athene cunicularia). [El proceso de urbanización y su efecto en la dispersión de las aves: el caso de la lechucita de las vizcacheras (Athene cunicularia).] Key words: Athene cunicularia, dispersal strategy, reproduction, survival, urban ecology. Palabras clave: Athene cunicularia, ecología urbana, estrategias de dispersión, reproducción, supervivencia. Abstract: Urbanization has become one of the greatest global landscape transformations. Usually, the spread of cities creates new habitats starkly different from the natural ones it replaces, and simplifies and homogenizes animal communities. Despite this general trend, some species are able to thrive and even prosper in urban ecosystems. Among birds, for example, nearly 20% of the roughly 10,000 described species can be found in cities. Thus, understanding the factors that allow certain individuals and species to persist within these landscapes, as well as the consequences for their population dynamics and structure, is as important as identifying the drivers of species loss. Dispersal, a fundamental event with influence on the demography and structure of populations, is among the main ecological processes that may be altered by urbanization. However, few studies have assessed the differences in this process between conspecifics living in their original habitats and those inhabiting cities. This thesis focuses on the dispersal of the Burrowing Owl (Athene cunicularia) in the city of Bahía Blanca (Argentina) and its rural surroundings. There, a specific monitoring program conducted annually from 2006 to 2019 has surveyed ca. 2,500 urban and ca. 3,200 rural nests of this species, recording reproductive parameters and marking ca. 2,000 adults and nestlings. This long-term study has been complemented with individual measurements of Burrowing Owls behavior. Specifically, we recorded the individual variation in the susceptibility to humans. This personality trait is included within a range of behaviors that encompasses risk taking, aggressiveness, and exploration and dispersal propensity, playing a role in the colonization of cities. The main hypothesis is that individuals disperse according to their phenotypes, although their dispersal decisions may be also influenced by the heterogeneous selective pressures observed in the study area. Furthermore, the coexistence of different dispersal strategies may play a positive or negative role in term of individual fitness, with potential effects in the population dynamic. Thus, the aim of this study is to understand the influence of individual cues (behavior, sex and age) and environmental factors (quality of natal and breeding zones, predation pressure and habitat type) in dispersal strategies of Burrowing Owls in adjacent but deeply different habitats, the city and their immediate rural area. Moreover, we assess whether dispersal decisions influence the biological effectiveness of individuals in both habitats in terms of reproductive parameters and survival. In Chapter 1 we focused on natal dispersal. we found that urban Burrowing Owl dispersed nearer than rural ones. Moreover, females, bold individuals and those born in poor quality territories dispersed farther. Females and rural individuals who settled far from their natal territories improved their reproductive output in their first breeding attempt, and this extended to both sexes and habitats when we consider productivity throughout the entire life. On the contrary, females that dispersed farther showed lower local survival. In Chapter 2 we explored the development of cooperative breeding, an uncommon strategy in this monogamous owl. we showed that cooperative families were mainly composed by three adults. The extra individuals were generally males born the last breeding season in the same territory, who delayed their dispersal to help their parents. The contribution of helpers can increase food provisioning, as evidenced by the fact that nestlings born in cooperative breeding units had a better physical condition. Cooperative breeding occurred more frequently in highly productive areas in which a greater number of conspecifics aggregated: the city and high quality rural areas. Furthermore, territories with helpers collaborating in reproductive tasks showed higher breeding success. The offspring raised in cooperative families had only a slight increase in their survival probabilities, compared with juveniles raised in common pairs. Survival showed temporal variations and the main factors driving survival differences were age and habitat: adults showed higher survival than juveniles, who had a higher survival in urban than in rural habitats. Finally, in Chapter 3, we studied breeding dispersal. we observed that a significant part of the population remained faithful to the same territory. Distances covered by dispersing individuals were shorter than those observed in natal dispersal. In general, females dispersed more frequently and travelled farther than males. Again, urban individuals were less prone to disperse, settling closer from the previous nest. In rural areas, individuals that suffered predation or breeding failure in a given territory, dispersed more frequently. However, bold individuals dispersed less than fearful ones, probably due to the higher ability of the former to cope with the disturbances suffered during the breeding period. The influence of behavior disappeared in the urban environment, where the main determinant of site fidelity was conspecific density. Academic year: 2018-2019.
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Ardeola is the scientific journal of the Spanish Ornithological Society. We analyse historical changes in citation, topics and foreign authorship of articles published in Ardeola from its first publication in 1954 up to last year, 2015, to test to what extent the persistence of the journal during the last 61 years has been due to support of authors, Society members, readers, editors or the whole ornithological community. Analyses were done within the context of the Red Queen game played by scientific journals competing for the best and more cited articles. The impact factor of Ardeola has increased from 1985 onwards both in absolute and relative terms. Thematic changes have followed trends of the general ornithological literature, without the journal specialising in particular topics or geographical regions. Foreign authorship decreased from 1954 up to the end of the 20th century, subsequently increasing again, a trend fuelled by coverage by Current Contents and the JCR, the establishment of English as the language of publication and recent Internet access though the BioOne platform. Ardeola is a traditional scientific journal, backed by a scientific society, whose future will be guaranteed by a reputation for rigour and quality sought by authors, reviewers and editors, supported by the members of the Spanish Ornithological Society and retaining its original objective: ‘to be a journal at the level of the best…, looking for a strong collaboration with foreign authors to promote the benefit of the Ornithology’.
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Edited by Francisco VALERA This section includes the abstracts of some of the PhD-Dissertations submitted in Spain during the 2015-2016 academic year as well as some others not published in earlier volumes of Ardeola. They are in alphabetical order by University where they were presented and, then, by year and alphabetical order of the author's surname. For the first time, this section includes a link to access the full version of the reviewed thesis when available. Esta sección incluye los resúmenes de algunas de las Tesis Doctorales en Ornitología defendidas en España en el curso 2015-2016 junto con otras no recogidas en reseñas anteriores. Se ha seguido una ordenación alfabética por universidades y, dentro de ellas, por año y autor. Por primera vez esta sección incluye un vínculo que permite acceder a la versión completa de la tesis reseñada en caso de que esté disponible. Informative note: In its section PhD-Dissertations Reviews in Ornithology, Ardeola reports any studies on ornithological issues presented in our country. The section is intended as an updated overview of the latest ornithological research performed mainly in Spain. In spite of the efforts of the editor to compile all the theses, we are aware that the collaboration of researchers (supervisors and doctorates) is needed to give a full view of ornithological research in Spain. We therefore invite the scientific community to report on their results (ardeola@seo.org). The Scientific Committee of SEO/BirdLife grants a biannual prize to the best Ph Dissertation included in this section. The prize is awarded in the corresponding Spanish Ornithological Conference. We are looking forward to hearing from you, also as proof of the relevance and quality of ornithological research in Spain. Nota informativa: Ardeola recoge en su sección Reseña de Tesis Doctorales en Ornitología aquellas tesis leídas en nuestro país que estudien temas ornitológicos con el fin de informar sobre las más recientes investigaciones desarrolladas, fundamentalmente en España, en este campo científico. A pesar de los esfuerzos que realizamos para reseñar todas las tesis concluidas, somos conscientes de que un registro completo y actual de las mismas requiere de la colaboración de los investigadores (directores y doctorandos). Por ello, invitamos a todos aquellos implicados en la realización de tesis en ornitología a que nos informen de sus resultados (ardeola@seo.org). El Comité Científico de SEO/BirdLife otorga con carácter bianual un premio a la mejor tesis doctoral reseñada en esta sección, que es entregado en el Congreso Español de Ornitología correspondiente. Esperamos vuestras noticias como buena señal de la pujanza de la investigación ornitológica en nuestro país.