Gaps and biases in the protection of transnational lakes: A global assessment [610443]

Landscape Ecology
Gaps and biases in the protection of transnational lakes: A global assessment
–Manuscript Draft–

Manuscript Number: LAND-D-20-00100
Full Title: Gaps and biases in the protection of transnational lakes: A global assessment
Article Type: Original research
Keywords: Gap analysis; conservation planning; transnational lake; international boundaries;
protected areas; global
Abstract: Context
National borders remain an impediment to efficient preservation of biodiversity and
ecosystems. For transboundary water resources, conservation planning becomes
more challenging, as competitive interests make these sensitive and productive
systems focal points of interstate conflicts.
Objectives
This study aims to explore at global scale for potential determinants of patterns of
divergence in the protection of transnational lakes along the different sides of national
borders.
Methods
Identifying 793 transnational lakes globally, we initially investigated protection
coverage at their water bodies. Next, we explored protection coverage patterns across
each lake’s catchment, in which we also quantified the extent and intensity of human
pressures. Socio-economic and political parameters were considered as potential
predictors of the observed patterns.
Results
Only half of the world’s transnational lakes are fully or partly covered by an existing
protected area. A 37% of the protected transnational lakes are subjected to same
extent of protection coverage across shared international borders, pattern that is not
driven by the relative area of the transnational lake found in the neighboring countries.
The results demonstrated that protection cover focuses mainly on the lakes’ water
surface ignoring the terrestrial surroundings, while the surface of 75% of the
catchments is subjected to intense human pressures.
Conclusions
Providing a first overview at global scale of the protection gaps of transnational lakes,
we demonstrate a failure of policy responses to cross-border biodiversity conservation
of critical and sensitive freshwater ecosystems, with such limitations likely to loom risks
for human well‐being and for the initiation of intense conflicts.
Powered by Editorial Manager® and ProduXion Manager® from Aries Systems Corporation

1
Title: Gaps and biases in the protection of transnational lakes: A global assessment 1
2
Anastasia I. Tsavdaridou1*, Antonios D. Mazaris1 3
4
5
1Department of Ecology, School of Biology, Aristotle University of Thessaloniki, 54636, Thessaloniki, 6
Greece 7
8
*author for correspondence: 9
Department of Ecology, School of Biology, Aristotle University of Thessaloniki, 54636, 10
Thessaloniki, Greece 11
email: [anonimizat] , tel.: 00306973754128 12
ORCID: 0000 -0002 -2407 -7673 13
14
15
Acknowledgments : This research is co -financed by Greece and the European Union (European Social 16
Fund – ESF) through the Operational Programme “Human Resources Development, Education and 17
Lifelong Learning” in the context of the project “Strengthening Human Resources Research Potential 18
via Doctorate Research” (MIS -5000432), implemented by the State Scholarships Foundation (ΙΚΥ). 19
20 Manuscript
Click here to download Manuscript
Ms_Tsavdaridou_Mazaris.doc

2
Abstract 21
22
Context. 23
National borders remain an impediment to efficient preservation of biodiversity and ecosystems. For 24
transboundary water resources , conservation planning becomes more challenging, as competitive 25
interests make these sensitive and productive systems focal points of interstate conflicts. 26
27
Objectives. 28
This study aims to explore at global scale for potential determinants of patterns of d ivergence in the 29
protection of transnational lakes along the different sides of national borders. 30
31
Methods. 32
Identifying 793 transnational lakes globally, we initially investigated protection coverage at their water 33
bodies. Next, we explored protection cove rage patterns across each lake’s catchment, in which we also 34
quantified the extent and intensity of human pressures. Socio -economic and political parameters were 35
considered as potential predictors of the observed patterns. 36
37
Results. 38
Only half of the world’ s transnational lakes are fully or partly covered by an existing protected area. A 39
37% of the protected transnational lakes are subjected to same extent of protection coverage across 40
shared international borders, pattern that is not driven by the relative area of the transnational lake 41
found in the neighboring countries. The results demonstrated that protection cover focuses mainly on 42
the lakes’ water surface ignoring the terrestrial surroundings, while the surface of 75% of the 43
catchments is subjected to i ntense human pressures. 44
45
Conclusions. 46
Providing a first overview at global scale of the protection gaps of transnational lakes, we demonstrate 47
a failure of policy responses to cross -border biodiversity conservation of critical and sensitive 48
freshwater ecos ystems, with such limitations likely to loom risks for human well ‐being and for the 49
initiation of intense conflicts. 50
51
Keywords 52
Gap analysis, conservation planning, transnational lake, international boundaries, protected areas, 53
global 54
55
56
57
58

3
1. Introduction 59
National borders are rarely being coincident with ecological borders, raising multiple challenges to 60
conservation initiatives (Lim 2014 ; Dallimer and Strange 2015) . Management plans and conservation 61
actions are often implemented at a national level, while spe cies, habitats, ecosystems spread over large 62
scales, not being confined by administrative boundaries (Akamani and Wilson 2011 ; Kark et al. 2015) . 63
Similarly, the various threats affecting the ecological integrity of a given site cannot be constrained by 64
national borders, as their source could potentially identified in distant locations which are often hosted 65
in other countries (Kark et al. 2015) . These connections have led to recognition that the 66
operationalization of conservation strategies should be shared across national borders. 67
68
Acknowledging the need for transboundary conservation (Rands et al. 2010 ; Thornton et al. 2018) an 69
expansion of transboundary protected areas (PAs) is noted globally, along with an increase of multi – 70
national cooperative initiativ es (Busch 2008 ; Thornton et al. 2018) . Nevertheless, political borders 71
remain a hindrance for efficient conservation, due to multiple factors that differentiate on either side of 72
the borders (Armitage et al. 2015; Dolezsai et al. 2015) . Differences in the national policies, political 73
priorities, legislative tools, governance structures and societal attributes, the lack of coordination 74
among administration schemes and the available funding could greatly result into unbalanced efforts 75
jeopardizing conservatio n efficiency (Akamani and Wilson 2011 ; Lim 2014 ; Petersen -Perlman et al. 76
2017 ). For example, protection gaps and inconsistencies are identified even at the European Union’s 77
network of PAs, the Natura 2000, which is the world’s largest conservation network that was 78
established by the implementation of very precise and standardized processes among member states 79
(Opermanis et al. 2012 ; Kati et al. 2015 ). 80
81
When it comes to transboundary inland water ecosystems, conservation planning becomes even more 82
challengi ng and complex (Lim 2014 ; Dolezsai et al. 2015 ). Actually, the conservation of inland water 83
ecosystems has been rather poor (Bush et al. 2014 ; Hermoso et al. 2015 ; Abell et al. 2017 ), with their 84
protection at transboundary level being subjected to plenty a dditional limitations. The functionality and 85
health of inland water ecosystems depend on both the water body and upstream catchment area which 86
often expands over large geographic regions (Lim 2014) . It is therefore likely that for a transboundary 87
ecosystem , the water body, its catchment area or both could be hosted by two or more countries. Still, 88
existing PAs largely ignore catchment boundaries, as well as the links between the upstream and 89
downstream drainage network (Bush et al. 2014 ; Dolezsai et al. 201 5). This is for example the case for 90
riparian systems, which may support unique biodiversity features but also regulate flow, water quality 91
and connectivity among lakes, ponds, wetlands and other inland water ecosystems (Bush et al. 2014 ; 92
Abell et al. 2017 ; Best 2019 ). A recent global study, highlighted huge conservation gaps of rivers and 93
their catchments (Abell et al. 2017) , raising further concerns on the actual level of protection of 94
freshwater ecosystems such as lakes at downstream areas. 95
96

4
Transnation al inland waters affect more than 40% of the world’s human population, as they are used 97
for a wide range of livelihood activities (Lim 2014 ; Best 2019 ). Constantly rising anthropogenic 98
stresses on water resources could often make transnational inland water ecosystems focal points for 99
interstate conflicts (Giordano et al. 2014; Lim 2014 ; Petersen -Perlman et al. 2017 ). While, formal and 100
informal transnational agreements and treaties constitute the means to regulate inland water 101
management and use (Giordano et al. 2014) , the designation of transboundary PAs remains the key tool 102
towards enhancing coherence of biodiversity conservation (Opermanis et al. 2012 ; Dallimer and 103
Strange 2015 ). 104
105
Regardless the wide scientific and political interest for the assessment of the global network of PAs and 106
the identification of the existing protection gaps (Rodrigues et al. 2004 ; Juffe -Bignoli et al. 2014 ; Abell 107
et al. 2017) the adequacy of transnational PAs has only rarely been assessed (Opermanis et al. 2012 ; 108
Thornton et al. 2 018). The evidence on the adequacy of protection of freshwater ecosystems is even 109
scarcer. Such studies are often limited in selected freshwater ecosystems (e.g. Danube river, the North 110
American and the African Great Lakes), exploring local or regional fac tors which could explain 111
patterns of protection coverage (Lim 2014 ; Dolezsai et al. 2015 ; Habersack et al. 2016) . To contribute 112
to this discussion, the objective of the present study is to provide a global assessment of transnational 113
lakes’ protection cove rage. 114
115
Lakes represent an excellent example of sensitive inland water ecosystems, with both their spatial and 116
ecological properties largely ignored during conservation planning (Servos et al. 2013 ; Tsavdaridou et 117
al. 2019; Katsiapi et al. 2020 ). They are subjected to multiple human related pressures that change their 118
surroundings and influence their physical, chemical and biotic characteristics, leading to impacts on 119
numerous processes and services (Schindler and Scheuerell 2002 ; Servos et al. 2013) . The w ater body 120
of a lake but also its catchment could be unequally shared by two or more countries, with protection 121
coverage driven by historic events, current political agendas or topological features. 122
123
Here, we conducted a global analysis exploring for poten tial determinants of patterns of divergence in 124
protection of transnational lakes along the different sides of national borders. We initially investigated 125
protection coverage at the water bodies of each lake. Next, we explored protection coverage patterns 126
across each lake’s catchment, in which we also quantified the extent and intensity of human pressures. 127
Socio -economic and political parameters were also considered as potential predictors of the observed 128
patterns. Our results are expected to provide a first overview at global scale of the protection gaps and 129
biases of transnational lakes, offering a basis to understand the patterns and barriers in their 130
conservation and highlight priorities towards achieving more efficient transnational conservation plans 131
in the future. 132
133
2. Material and Methods 134

5
135
2.1 Transnational lakes and their catchments 136
137
Spatial data on distribution of transnational lakes were derived from HydroLAKES (Messager et al. 138
2016) , a database that provides georeferenced information for approxi mately 1.43 million lakes at 139
global scale. HydroLAKES database includes polygons of natural, regulated and artificial freshwater 140
and saline lakes, with a surface area of at least 0.10 km2. To identify transnational lakes, we overlaid 141
the lake polygons with countries’ borders (Eurostat, version 2018). Lakes that their surface extended 142
beyond the national borders of one country were maintained for our analysis. To validate the selection 143
of the transnational lakes we used Google Earth images and literature sou rces. Despite the fact that 144
Caspian Sea is the world’s largest inland body of water, it was not included in the analysis, as it was 145
expected to bias results due to its size. Following the former process, we ended up with a total number 146
of 793 lakes shared among 123 countries. 147
148
We used spatial data on flow direction derived from “Hydrologic Derivatives for Modelling and 149
Applications (HDMA) database” (Verdin 2017) , including information on elevation and slope to 150
identify the direction of surface run -off towar ds the transnational lakes and delineate their catchment 151
area. We divided the area of each catchment at national level along the borderline of the countries it 152
crossed. The area of the catchment hosted within the territory of the countries sharing the tran snational 153
lake was then estimated. 154
155
2.2 Spatial patterns of conservation coverage 156
157
To identify the protection coverage of transnational lakes and their catchments we overlaid their 158
georeferenced location with the spatial arrangement of global PAs, derived from the World Database 159
on Protected Areas (IUCN and UNEP 2018, version January 2018). Next, we calculated the total lake’s 160
area covered by PAs, but also the area of the lake covered in each country. To avoid overestimating of 161
the total protection coverage in cases where PAs spatially overlap, we merged their polygons in each 162
transnational lake. The same process was repeated for their catchments. We applied Spearman’s rank – 163
order correlation to identify potential associations between surface area of the prot ected lakes and the 164
percentage coverage. We repeated the analysis for their catchment area. 165
166
Potential differences or biases in protection coverage could be related to the relative surface of the lake 167
or its catchment that falls within the different countr ies that share them. For example, it might be 168
possible to obtain a full coverage of the surface of a lake from one side of the boarders if this surface in 169
the specific country is very limited. Under the same context, potential conservation biases would be 170
more pronounced in cases that neighboring countries share similar surfaces of the lake but there are 171
significant differences in their protection coverage. To delineate these patterns, we develop two 172

6
indices, and applied them for lakes (n=400) and their cat chments that were shared by two countries. 173
The first index (hereafter is called the surface ratio index ) allowed us to provide a metric of the relative 174
surface of a transnational lake and its catchment area shared between neighboring countries. The 175
second index (hereafter called protection ratio index ) was used to explore whether same patterns of 176
protection cover were identified in all the countries sharing the transnational lake and catchment area. 177
178
The surface ratio index, was produced for every lake, a nd catchment, and was equal to the ratio of the 179
minimum and the maximum percentage of the surface area that belonged to each country. The surface 180
ratio index gets a value of one when an equal surface of the lake or the catchment is shared by all 181
neighborin g countries. The index approximates zero in cases that the area of a lake, or catchment, is 182
mainly expanding in only one country over the other (e.g. surface ratio index gets 0.01 when 99% of 183
the area belong to only one of two neighboring countries). Simil arly, to calculate the protection ratio 184
index, first, we accounted the difference between the maximum and the minimum percentage of the 185
area of a lake, or catchment, covered from PAs in each country. Then, we subtracted the derived value 186
from the maximum c orresponding difference accounted among all the cases. To standardize the index 187
we divided its values with 100 so that it ranged from zero to one. The index gets its maximum value 188
(i.e. one) if there is an absolute similarity in protection coverage by the two countries and gets smaller 189
as differences in coverage increase. Next, we applied a Spearman’s rank -order correlation between the 190
two indices, to delineate whether protection coverage was driven by the relative area of the 191
transnational lake, and catchm ent, found in the neighboring countries. 192
193
Furthermore, to investigate whether lakes and catchments with same patterns of protection cover 194
identified in all neighboring countries tended to be protected at larger extent we applied a Spearman’s 195
rank-order c orrelation between the protection ratio index and the maximum coverage from PAs noted 196
in either side of the borders. 197
198
2.3 Human pressures 199
To assess the human impact at catchment level, we quantified the extent and intensity of human 200
pressures at the catch ment areas of the protected transnational lakes using the revised human footprint 201
map (Venter et al. 2018) , with a global spatial resolution of 1km. The cumulative score of human 202
pressures ranges from 0 -50, while four is considered (Watson et al. 2016 ; Jones et al. 2018) as a 203
threshold indicating areas with significant human activity, that could potentially threaten species and 204
habitats integrity. 205
206
We identified the presence of human pressures (human footprint score ≥ 1) in the catchments of the 207
protected transnational lakes, where we also calculated the percentage of the land under intense human 208
pressure (human footprint score ≥ 4). Furthermore, we applied a Spearman’s rank -order correlation to 209
explore whether intens e human pressures noted in the catchment area in each side of the borders could 210

7
drive the patterns of protection cover identified in each neighboring country. 211
212
2.4 Socio -economic and geopolitical drivers 213
To investigate whether potential difference s in protection coverage of the transnational lakes could be 214
driven by socio -economic or geopolitical factors, we selected a set of variables at national scale. In 215
total three variables were considered: a) the rate of human population growth (World Bank 20 17a) as 216
metric of demography, b) the human development index (UNDP 2017) as metric of economy and 217
development and c) the index of political stability and absence of violence/ terrorism (World Bank 218
2017b) as metric of governance quality. Then, we applied Sp earman’s rank -order correlations to 219
explore for potential associations between each variable and the percentage of protection cover of each 220
protected transnational lake in either sides of the border. 221
222
In addition, we explored whether differences in so cio-economic and political status of the countries 223
sharing a transnational lake could potentially be associate with the differences in protection cover. For 224
the protected lakes spanning in two countries, we calculated the differences between the maximum an d 225
the minimum values of the socioeconomic and political variables of the countries where each lake 226
expanded. Then, we applied a Spearman’s rank -order correlation between the differences of the 227
maximum and the minimum percentage of cover from PAs and the di fferences of the socioeconomic 228
and political variables. 229
230
We run the spatial analyses using ArcMap 10.5.1 Geographic Information Systems software of 231
the Environmental Systems Research Institute (ESRI). All statistical analyses were run using IBM 232
SPSS Stati stics 25. 233
234
3. Results 235
236
3.1 Patterns of protection cover 237
238
Out of the 793 transnational lakes recognized in the planet, only 407 (~51%) were fully or partly 239
covered by a PA (Fig. 1). The majority of the transnational lakes (n=381; 48%) was hosted in Europe, 240
followed by Asia (n=168; 21%). More than 60% of the European lakes were covered by PAs to some 241
extent, while for transnational lakes located in Asia this percentage dropped to less than 23%. The rest 242
31% of the transnational lakes were located in North (n= 83) and South (n=92) America and in Africa 243
(n=69). About 73% of transnational lakes found in North and 53% of the lakes found in South America 244
were overlaid with PAs, while in Africa the percentage was estimated to be about 43%. 245
246
Globally, only one fifth (~20%) of the transnational lakes had cover from PAs that was equal or 247
exceeded 90% of their surface area . In almost half (n=87) of the 179 transnational lakes with high 248
cover (≥90%), we also found high cover at their catchment. Furthermore, for protected transnational 249

8
lakes we noted that the smaller the water body and catchment surface, the higher percentage of 250
protection ( water body: r s= -0.384, p<0.05 catchments: r s= -0.424, p<0.05). 251
252
In only 37% of the protected transnational lakes, we observed absolute similarity in protection 253
coverage by the two neighboring countries ( protection ratio index = 1) (Fig.2), while for catchments 254
this number was diminished to less than one fifth of the cases. Our analysis demonstrated that in the 255
case of the lakes the highe r the protection ratio index , the higher the percentage of protection cover in 256
either side of the borders (r s= 0.315; p<0.05), while such relation was not observed for their catchments 257
(p>0.05). Still, we found that the relative area of the transnational l ake, and catchment, found in the 258
neighboring countries did not bias the protection coverage noted in each side of the borders (p>0.05 in 259
both cases). Consequently, such results suggest that even if a lake, or catchment, were evenly shared by 260
two countries, they were not subjected to similar levels of protection at both sides of the borders (Fig. 261
3). 262
263
3.2 Human pressures 264
265
Human pressures were identified in the vast majority (~90%) of the protected transnational lakes’ 266
catchments, while more than 75% of the se catchment areas were subjected to intense human pressure 267
(i.e. human f ootprint score ≥ 4). In more than 40% of the cases, we noted that the proportion the land 268
under intense human pressures exceeded 80% of the catchment area in both sides of the borders. We 269
found that the percentage of land under intense human pressures was significantly negatively 270
associated with the protection cover of the catchment area in each country (r s=-0.169; p<0.01), but was 271
not related with the protection coverage of lakes (p>0.05). 272
273
3.3 Socio -economic and geopolitical variables as predictor s of conservation 274
275
Our analysis did not reveal any significant association between protection cover of the transnational 276
lakes and the metrics of human development, political stability or violence/terrorism (p>0.05 in all 277
cases). Still, protection cover of lakes was negatively associated with the national population growth 278
rate, with lower cover identified in part of countries with higher population growth rates (r s=-0.144; 279
p<0.01). 280
281
Our results demonstrated no significant association between pairwise diff erences of protection cover 282
and the different socioeconomic metrics explored (p>0.05 in all cases). 283
284
4. Discussion 285
286
Quantifying gaps and mismatches in protection cover is fundamental for achieving efficient and long 287

9
lasting conservation of ecosystems, biodi versity and habitats (Rodrigues et al. 2004 ; Abell et al. 2017) . 288
Here, we showed that only half of the transnational lakes at global scale are subjected to a degree of 289
protection coverage, with only limited lakes globally being sufficiently covered by PAs. Our analysis 290
showed inconsistencies in protection coverage across the borders and a failure in protecting the 291
transnational lake’s catchments that are often exposed to numerous impacts. Such gaps and biases in 292
transnational protection cover provide suppor t to long standing discussions on the need to enhance 293
transboundary cooperation and coordination, as the mean to set the common goal of the efficient 294
conservation of the freshwater ecosystems (Linke et al. 2011 ; Abell et al. 2017) . 295
296
In recent years, the ne cessity for cross -border coherence regarding the conservation of biodiversity and 297
ecosystems is widely recognized, trigging some cross boarder initiatives (Busch 2008 ; Kark et al. 298
2015 ). Such efforts are likely to be mirrored by the relative similar, cross -border patterns of 299
conservation coverage of the highly protected lakes. Still, we caution that any such rather encouraging 300
finding does not necessarily guarantee the efficiency of these areas and the existence of actual 301
international cooperation in their management (Lim 2014 ; Di Minin and Toivonen 2015) . This is the 302
case for example of lake Ohrid at the Albanian – Northern Macedonian borders in Southeast Europe, 303
where despite high protection cover noted in both sides of the borders, degradation of water qu ality and 304
natural habitats has been registered (Kostoski et al. 2010 ; Trajanovski et al. 2019) . Therefore, we 305
caution that although designation of PAs is a key factor for the conservation of biodiversity and 306
ecosystems, additional steps should be taken to ensure their adequacy (e.g. effective PA management) 307
(Watson et al. 2014 ; Gray et al. 2016 ; Kuempel et al. 2018 ), that particularly in the case of 308
transboundary areas requires long -lasting transnational cooperation (Lim 2014; Armitage et al. 2015 ; 309
Petersen -Perlman et al. 2017 ). 310
311
Identifying intense human pressures in the majority of the under study catchments concurs with the 312
notion that lakes are of the most threatened ecosystems, urging for enhanced conservation interventions 313
(Martinuzzi et al. 2014 ; Venter et al. 2016 ). Still, opportunities for conservation are constrained, as a 314
limited number of these areas are currently free of human pressures, while potential expansion of the 315
PAs will most likely raise various conflicts between conservation and multi ple human stakeholders 316
(Lambin and Meyfroidt 2011 ; Venter et al. 2016 ). An approach that will balance human and 317
conservation needs could meet these challenges, with the adoption of alternative land use management 318
and the transition to more environmental ef ficient and sustainable human activities (DeFries et al. 319
2007 ; Lambin and Meyfroidt 2011) . This is the case for example of the management interventions 320
implemented in the Prespa lakes’ catchment, an area of high conservation interest in Southeast Europe 321
that spans Albania, Republic of North Macedonia and Greece. Organic farming, sustainable rural 322
development and traditional livestock farming are some of the measures that aimed to contribute to the 323
conservation and maintenance of the area’s ecosystems throug h the change of the productive sector 324
practices (Vasilijević and Pezold 2011) . We caution that particularly in transnational areas, it is 325

10
important that such approaches should be applied jointly, with the collaboration of all countries 326
involved. 327
328
A number of studies, focusing at given freshwaters, nation al or regional scales (Hermoso et al. 2015 ; 329
Carrizo et al. 2017 ; Tsavdaridou et al. 2019 ) have demonstrated that protection of freshwater 330
catchments is often very limited, posing serious barriers in conservation. Obviously expanding 331
protection zones away f rom the actual location where species, habitats of ecosystems of conservation 332
concern have been recognized is not an easy task (Hermoso et al. 2016) . Catchment areas often expand 333
over large geographical scales, enclosing human settlements, or as shown here , various human related 334
activities and infrastructure. Still, even if practical limitations are apparent (i.e. land use/societal 335
conflicts, increased costs) efficient planning could be accomplished based on prioritization tools such 336
as systematic conservat ion planning processes (Dolezsai et al. 2015; Hermoso et al. 2015) . 337
338
In transnational catchments, ensuring a high degree of protection is even more challenging (Armitage 339
et al. 2015; Dolezsai et al. 2015) , as cooperation and coordination is required among st multiple 340
countries with given differences in their environmental policies, political priorities and governance 341
structures (Lim 2014 ; Petersen -Perlman et al. 2017) . We showed that same patterns of protection cover 342
were identified only in limited number o f catchments, potentially reflecting the difficulties that 343
different political agendas and often competitive national interests raise to the accomplishment of 344
coordinated protection at catchment level (Lim 2014 ; Munia et al. 2016 ). Indicative of such chall enges 345
is the case of the lake Chad catchment in Africa, where despite the existing water agreements, droughts 346
and water shortages in 1980s resulted in unilateral decisions of riparian countries for water allocation 347
with multiple environmental and socioecon omic consequences (Asah 2015; Okpara et al. 2015) . 348
Another example is of Euphrates catchment in Western Asia, where, in lack of catchment -wide 349
coordination and management, each riparian country, developed independently (dams, industrial 350
irrigation etc.), a iming to maximize the national economic benefit. The result was considerable 351
ecological and social impacts that contributed even to the current political instability in the area 352
(Zeitoun et al. 2013) , highlighting the necessity of integrated water resource s management at catchment 353
scale, with the development of strong transnational collaboration and commitment. 354
355
Understanding patterns and barriers in conservation often relies on our ability to detected social, 356
political or economic drivers (Amano and S utherland 2013 ; Barnes et al. 2016 ). Still, our analyses 357
failed to detect a clear linkage between transnational lakes’ protection and the different socio -economic 358
and political variables. There are several plausible reasons for this lack of association. Fi rst, even 359
though the variables selected here have been identified by previous studies to play a critical role in PAs 360
establishment and conservation initiatives, the complexity of the studied system (e.g. transnational 361
protection of the same ecological targ et, scale of the analysis) might somehow mask their relative 362
impact on the observed protection patterns. Under the same context, the services that are offered by 363

11
lakes (e.g. water for multiple purposes, fertile lands in the surroundings) and thus obstacles for 364
establishment of conservation schemes might be of great interest for local communities, with any such 365
tendency deviating from national statistics. This is the case for example of the two transnational lakes 366
Ihema and Rweru, sited both in the borders o f Republic of Rwanda with Tanzania and Burundi 367
respectively, with all countries sharing similar socio -economic and political characteristics. In Republic 368
of Rwanda, almost full cover from the PAs is noted in lake Ihema, as the water body is located in the 369
wider protected area of Akagera National Park. In the case of lake Rweru, high cover is identified only 370
in Burundi, while in the Republic of Rwanda the protection cover is limited, despite the fact that the 371
lake constitutes one of the important freshwater ecosystems of the country (Karame et al. 2017). A 372
restriction of human activities (e.g. agriculture) in the area may threaten the survival of the local 373
communities, as they are highly depended on the freshwater resources, making the designation of PAs 374
particular challenging (Karame et al. 2017). Therefore, it is likely that lakes are unique and complex 375
systems and protection priorities and patterns might be associated with decision or processes which are 376
taken at different scales. Hence, detailed research i s needed to highlight the critical social, political or 377
economic drivers that influence conservation patterns at multiple scales. 378
379
5. Conclusion 380
Our results clearly demonstrate that a greater effort is required for achieving efficient conservation of 381
lakes at transnational scale. As political considerations often overwhelm hydrologic and ecosystem 382
needs, transnational inland waters always constitute reasons for conflict and cooperation between 383
neighbor countries (Lim 2014 ; Petersen -Perlman et al. 2017) . Ther efore, it is important to facilitate the 384
constructive dialogue and collaboration at multi -national level and create conditions for achieving 385
efficient conservation at transnational catchment scale. 386
387

12
References 388
Abell R, Lehner B, Thieme M, Linke S (2017 ) Looking beyond the fenceline: Assessing protection 389
gaps for the world's rivers . Conservation Letters 10: 384 -94 390
Akamani K, Wilson PI (2011 ) Toward the adaptive governance of transboundary water resources . 391
Conservation Letters 4: 409 -16 392
Amano T, Sutherland WJ (2013 ) Four barriers to the global understanding of biodiversity conservation: 393
wealth, language, geographical location and security . Proceedings of the Royal Society B: Biological 394
Sciences 280: 20122649 395
Armitage D, de Loë RC, Morris M, Edwards TWD , Gerlak AK, Hall RI, Huitema D, Ison R, 396
Livingstone D, MacDonald G (2015 ) Science –policy processes for t ransboundary water governance. 397
Ambio 44: 353 -66 398
Asah ST (2015 ) Transboundary hydro ‐politics and climate change rhetoric: an emerging 399
hydro‐security complex in the lake Chad basin . Wiley Interdisciplinary Reviews: Water 2: 37 -45 400
Barnes MD, Craigie ID, Harrison LB, Geldmann J, Collen B, Whitmee S, Balmford A, Burgess ND, 401
Brooks T, Hockings M (2016 ) Wildlife population trends in protected areas predicted by national 402
socio -economic metrics and body size . Nature Communications 7: 1 -9 403
Best J (2019 ) Anthropogenic stresses on the world’s big rivers . Nature Geoscience 12: 7 -21 404
Busch J (2008 ) Gains from configuration: The transboundary protected area as a conservation tool . 405
Ecological Economics 67: 394 -404 406
Bush A, Hermoso V, Linke S, Nipperess D, Turak E, Hughes L (2014 ) Freshwater conservation 407
planning under climate change: demo nstrating proactive approaches for Australian Odonata . Journal of 408
Applied Ecology 51: 1273 -81 409
Carrizo SF, Lengyel S, Kapusi F, Szabolcs M, Kasperidus HD, Scholz M, Markovic D, Freyhof J, Cid 410
N, Cardoso AC (2017 ) Critical catchments for freshwater biodivers ity conservation in Europe: 411
identification, prioritisation and gap analysis . Journal of Applied Ecology 54: 1209 -18 412
Dallimer M, Strange N (2015 ) Why socio -political borders and boundaries matter in conservation . 413
Trends in Ecology & Evolution 30: 132 -39 414
DeFries R, Hansen A, Turner BL, Reid R, Liu J (2007 ) Land use change around protected areas: 415
management to balance human needs and ecological function . Ecological Applications 17: 1031 -38 416
Di Minin E, Toivonen T (2015 ) Global protected area expansion: creating more than paper parks . 417

13
BioScience 65: 637 -38 418
Dolezsai A, Sály P, Takács P, Hermoso V, Erős T (2015 ) Restricted by borders: trade -offs in 419
transboundary conservation planning for large river systems . Biodiversity and conservation 24: 1403 – 420
21 421
Eurostat (2018 ) Countries , Geographical Information and Maps (GISCO) . 422
https://ec.europa.eu/eurostat/web/gisco/geodata/reference -data/administrative -units -statistical – 423
units/countries . Accessed 24 Jan. 2019 424
Giordano M, Drieschova A, Duncan JA, Sayama Y, De Stefano L, Wolf AT ( 2014 ) A review of the 425
evolution and state of transboundary freshwater treaties . International Environmental Agreements: 426
Politics, Law and Economics 14: 245 -64 427
Gray CL, Hill SLL, Newbold T, Hudson LN, Börger L, Contu S, Hoskins AJ, Ferrier S, Purvis A, 428
Scharlemann JPW ( 2016 ) Local biodiversity is higher inside than outside terrestr ial protected areas 429
worldwide. Nature Communications 7: 1 -7 430
Habersack H, Hein T, Stanica A, Liska I, Mair R, Jäger E, Hauer C, Bradley C (2016 ) Challenges of 431
river basin management: current status of, and prospects for, the River Danube from a river engineering 432
perspective. Science of the Total Environment 543: 828 -45 433
Hermoso V, Filipe AF, Segurado P, Beja P (2015 ) Filling gaps in a large reserve network to address 434
freshwater conservation needs. Journal of Environmental Management 161: 358 -65 435
Hermoso V, Abell R, Linke S, Boon P (2016 ) The role of protected areas for freshwater biodiversity 436
conservation: challenges and opportunities in a ra pidly changing world . Aquatic Conservation: Marine 437
and Freshwater Ecosystems 26: 3 -11 438
IUCN (International Union for the Conservation of Nature), UN Environment Programme (UNEP) 439
(2018) World database on protected areas . IUCN, Gland, Switzerland, UNEP, Paris . 440
www.protectedplanet.net . Accessed 30 January 2018 441
Jones KR, Venter O, Fuller RA, Allan JR, Maxwell SL, Negret PJ, Watson JEM ( 2018 ) One-third of 442
global protected land i s under intense human pressure. science 360: 788 -91 443
Juffe -Bignoli D, Burgess ND, Bingham H, Belle EMS, de Lima MG, Deguignet M, Bertzky B, Milam 444
AN, Martinez -Lopez J, Lewis E, Eassom A, Wicander S, Geldmann, J, van Soesbergen A, Arnell AP, 445
O’Connor B, Par k S, Shi YN, Danks FS, MacSharry B, King ston N (2014) Protected Planet Report 446
2014. UNEP -WCMC: Cambridge, UK 447
Karame P , Avalos T, Gashakamba F (2017 ) Towards wise use of wetlands of special importance in 448

14
Rwanda – Case Study: Rweru -Mugesera wetland. ARCOS Ne twork. 449
http://www .arcosnetwork .org/uploads /2018/03/ Rweru -Mugesera _assessment _Report .pdf. Accessed 28 450
December 2019 451
Kark S, Tulloch A, Gordon A, Mazor T, Bunnefeld N, Levin N (2015 ) Cross -boundary c ollaboration: 452
key to the conservation puzzle . Current Opinion in Environmental Sustainability 12: 12 -24 453
Kati V, Hovardas T, Dieterich M, Ibisch PL, Mihok B, Selva N (2015 ) The challenge of implementing 454
the European network of protected areas Natura 2000, Conservation Biology 29: 260 -70 455
Katsiapi M, Genitsaris S, Stefanidou N, Tsavdaridou A, Giannopoulou I, Stamou G, Michaloudi E, 456
Mazaris AD, Moustaka -Gouni M (2020 ) Ecological Connectivity in Two Ancient Lakes: Impact Upon 457
Planktonic Cyanobacteria and Water Q uality . Water 12: 18 458
Kostoski G, Albrecht C, Trajanovski S, Wilke T (2010 ) A freshwater biodiversity hotspot under 459
pressure –assessing threats and identifying conservation needs for ancient Lake Ohrid . Biogeosciences 460
7: 3999 -4015 461
Kuempel CD, Adams VM, Possi ngham HP, Bode M (2018 ) Bigger or better: The relative benefits of 462
protected area network expansion and enforcement for the conserv ation of an exploited species. 463
Conservation Letters 11: e12433 464
Lambin EF, Meyfroidt P (2011 ) Global land use change, economic globalization, and the looming land 465
scarcity . Proceedings of the National Academy of Sciences 108: 3465 -72 466
Lim M (2014 ) Is water different from biodiversity? Governance criteria for the effective management 467
of transboundary resources . Review of European, Comparative & International Environmental Law 23: 468
96-110 469
Linke S, Turak E, Nel J (2011 ) Freshwater conservation planning: the case for systematic approaches . 470
Freshwater Biology 56: 6 -20 471
Martinuzzi S, Januch owski‐Hartley SR, Pracheil BM, McIntyre PB, Plantinga AJ, Lewis DJ, Radeloff 472
VC ( 2014 ) Threats and opportunities for freshwater conservation under future land use change 473
scenarios in the United States . Global change biology 20: 113 -24 474
Messager ML, Lehner B, Grill G, Nedeva I, Schmitt O (2016 ) Estimating the volume and age of water 475
stored in global lakes u sing a geo -statistical approach . Nature Communications 7: 1 -11. doi: 476
10.1038/ncomms13603. Data is available at: www.hydrosheds.org. Accessed 20 January 201 8 477
Munia H, Guillaume JHA, Mirumachi N, Porkka M, Wada Y, Kummu M (2016 ) Water stress in global 478
transboundary river basins: significance of upstream water use on downstream stress . Environmental 479

15
Research Letters 11: 014002 480
Okpara UT, Stringer LC, Dougill AJ, Bila MD ( 2015 ) Conflicts about water in Lake Chad: Are 481
environmental, vulnerability a nd security issues linked? . Progress in Development Studies 15: 308 -25 482
Opermanis O, MacSharry B, Aunins A, Sipkova Z (2012 ) Connectedness and connectivity of the 483
Natura 2000 network of protected areas across country borders in the European Union . Biological 484
conservation 153: 227 -38 485
Petersen -Perlman JD, Veilleux JC, Wolf AT ( 2017 ) International water conflict and cooperation : 486
challenges and opportunities. Water Internation al 42: 105 -20 487
Rands MRW, Adams WM, Bennun L, Butchart SHM , Clements A, Coomes D, Entwistle A, Hodge I, 488
Kapos V, Scharlemann JPW ( 2010 ) Biodiversity conservation: challenges beyond 2010 . science 329: 489
1298 -303 490
Rodrigues ASL, Akcakaya HR, Andelman SJ, Bakarr MI, Boitani L, Brooks TM, Chanson JS, 491
Fishpool LDC , Da Fonseca GAB , Gaston KJ ( 2004 ) Global gap analysis: priority regions for 492
expanding the global protected -area ne twork. BioScience 54: 1092 -100 493
Schindler DE , Scheuerell MD ( 2002 ) Habitat coupling in lake ecosystems . Oikos 98: 177 -89 494
Servos MR, Munkittrick KR, Constantin G, Mngodo R, Aladin N, Choowaew S, Hap N, Kidd KA, 495
Odada E, Parra O (2013 ) Science and management of transboundary lakes: Lessons learned from the 496
global environment facility program . Envir onmental Development 7: 17 -31 497
Thornton DH, Wirsing AJ, Lopez‐Gonzalez C, Squires JR, Fisher S, Larsen KW, Peatt A, Scrafford 498
MA, Moen RA, Scully AE ( 2018 ) Asymmetric cross ‐border protection of pe ripheral transboundary 499
species. Conservation Letters 11: e12430 500
Trajanovski S, Gjoreska BB, Kenderov L, Trajanovska S, Zdraveski K, Trichkova T (2019 ) Potential 501
threats to benthic macroinvertebrate fauna in Lake Ohrid watershed: Water pollution and alien species . 502
Acta Zoologica Bulgarica Supplement 13: 91 -98 503
Tsavdaridou AI, Moustaka ‐Gouni M, Katsiapi M, Mazaris AD ( 2019 ) Gaps in the protection of 504
European lakes . Aquatic Conservation: Marine and Freshwater Ecosystems 29: 1726 -34 505
United Nations Development Programme (UNDP) (2017 ) The human development index . 506
http://hdr.undp.org/en /data . Accessed 24 Jan. 2019 507
Vasilijević M, Pezold T (2011 ) Crossing borders for nature. European example s of transboundary 508
conservation. IUCN Programme Office for South -Eastern Europe, Belgrade, Serbia 509

16
Venter O, Sanderson EW, Magrach A, Allan JR, Beher J, Jones KR, Possingham HP, Lau rance WF, 510
Wood P, Fekete BM ( 2018 ) Last of the Wild Project, Version 3 (LWP -3): 2009 Huma n Footprint, 2018 511
Release. Palisades, NY: NASA Socioeconomic Data and Applications Center (SEDAC) 10: 512
H46T0JQ4. https://doi.org/10.7927/H46T0JQ4. Accessed 13 May 2018 513
Venter O, Sanderson EW, Magrach A, Allan JR, Beher J, Jones KR, Possingham HP, Laurance WF, 514
Wood P, Fekete BM ( 2016 ) Sixteen years of change in the global terrestrial human footprint and 515
implications for biodiversity conservation . Nature Communications 7: 1-11 516
Verdin KL (2017 ) Hydrologic Derivatives for Modeling and Analysis —A new global high -resolution 517
database. In.: US Geological Survey. data release https://doi.org/10.5066/F7S180ZP. Accessed 15 518
February 2018 519
Watson J EM, Jones KR, Fuller RA, Di Marco M, Segan DB, Butchart SHM , Allan JR, 520
McDonald ‐Madden E, Venter O (2016 ) Persistent disparities between recent rates of habitat 521
conversion and protection and implications for future global conservation targets . Conservation Letters 522
9: 413 -21 523
Watson JEM, Dudley N, Segan DB, Hockings M (2014 ) The performance and potent ial of protected 524
areas. Nature 515: 67 -73 525
World Bank (2017a ) Population growth (annual %) , World Development Indicators. The World Bank 526
Group . data.worldbank.org/indicator/ . Accessed 24 Jan. 2019 527
World Bank (2017b ) Political Stability and Absence of Violence/Terrorism (Percentile Rank) , World 528
Governance Indicators . The World Bank Group . data.worldbank.org/indicator/ . Accessed 30 Jan. 201 8 529
Zeitoun M, Goulden M, Tickner D (2013 ) Current and future chall enges facing transb oundary river 530
basin management. Wiley Interdisciplinary Reviews: Climate Change 4: 331 -49 531
532

17
Figures and captions 533
534
535
536
Fig. 1. (A) Global distribution of transnational lakes; red dots show lakes which are covered to some 537
extent by protected areas (PAs); yellow dots show lakes which do not overlap with a PA. (B, C & D) 538
Examples of spatial cover of transnational lakes from PAs. (B) High cover of the water body only in 539
one country, Lake Titicaca, Peru (PE) and Bolivia (BO). (C) Limited cover of the water body in both 540
countries, Lake Maggiore, Italy (IT) and Switzerland (CH). (D) High cover of the water body in both 541
countries, Lake Khanka, Russia (RU) and China (CN). 542
543

18

544
545
Fig. 2. The transnational lakes that are covered to some extent by protec ted areas (PAs) categorized 546
based on the maximum coverage from PAs noted in either side of the borders and the protection ratio 547
index . The maximum protection was organized in five groups: “Low”, “Low/Medium”, 548
“Medium/High”, “High” and “Absolute”, correspon ding to >0 to <25, 25 to <50, 50 to <75, 75 to <100 549
and 100 percentage of cover from the PAs respectively. The protection ratio index was organized in 550
five groups: “Low”, “Low/Medium”, “Medium/High”, “High ” and “Absolute” corresponding to ≥0 to 551
<0.25, 0.25 to <0.50, 0.50 to <0.75, 0.75 to <1.00 and 1.00 respectively. 552
553

19

554
555
Fig. 3. The association between the relative surface of a lake covered by each neighboring country and 556
the protection cover offered by each one of them. The surface ratio index is a metric of the relative 557
surface of the lake that falls within the different neighboring countries (see method section for more 558
details). The protection ratio index is a metric of the similarity of protection cover between the 559
countries that share the lake (see me thod section for more details); for illustration purposes values of 560
protection ratio index were grouped into five classes. Box represents the 75 and 25 percentiles, thick 561
black lines represent median values, the vertical lines represent upper and lower lim its of the surface 562
ratio index. 563
564

Fig.1.jpg
Fig. 1
Click here to download Figure Fig.1.tiff

Fig.2.jpg
Fig. 2
Click here to download Figure Fig.2.tiff

Fig.3.jpg
Fig. 3
Click here to download Figure Fig.3.tiff

Department of Ecology,
School of Biology, U.P. Box 119,
Aristotle University, 54124,
Thessaloniki, Greece
Tel: +30 69 73754128
Email: atsavda @bio.auth.gr
25/02/2020

Dear Prof. Jianguo (Jingle) Wu ,
I, along with my coauthor, would be grateful if you woul d consider the attached manuscript entitled “ Gaps and
biases in the protection of transnational lakes: A global assessment ” for publication in Landscape Ecology as
an Original Research Article .
The efficiency of cons ervation network s along with the investi gation of the spatial properties of conservation
remain critical subjects for scientists and policy makers. Over the last years Landscape Ecology has published
several papers in this area (e.g. Lecina -Diaz et al., 2019; Landscape Ecol 34 , 2307 -2321 ; Trivin o et al., 2018;
Landscape Ecol 33, 659 -673; McCune et al., 2017; Landscape Ecol 32,871 -882). Under the same context, a
specific interest for the conservation of the unique freshwater ecosystems is increasing (e.g. Jiao et al., 2020;
Landscape Ecol (in pres s); McCullough et al., 2019; Landscape Ecol 34, 2703 -2718; Little and Altermatt , 201 8;
Landscape Ecol 33 , 1519 -1531 ). Here, we set out to make a step advance in this thread of research conducting
a global analysis to explore for potential determinants of patterns of divergence in protection of transnational
lakes along the different sides of national borders.
Our study focuses on 793 transnational lakes and their catchment area . For our analysis, we consider
geographical, socio -economic and political parameters and we quantify the extent and intensity of human
pressures within the terrestrial surroundings of the lakes . We find that only half of the transnational lakes are
fully or partly covered by an existing protected area . A 37% of the protected transnational lakes are subjected
to same extent of protection coverage across the shared international borders, pattern that is not biased by
the relative area of the trans national lake found in the neighboring countries. Our results show that protection
cover focuses mainly on the lakes’ water body and ignores their terrestrial surroundings, where intense human
pressures are identified in 75% of the cases .
Our results pro vide a first overview at global scale of the protection gaps and biases of transnational lakes
indicating the challenges that they raise to cross -border conservation initiatives for the biodiversity of the
sensitive freshwater ecosystems . Given that this m anuscript deals with up -dated issue and contributes to an
ongoing debate, w e believe that matches the aim of your journal , stimulating further discussions by a broad
readership.
As potential reviewers for this manuscript, we could suggest:
1. Prof. Ulrich Sommer, Helmholtz Center for Ocean Research (GEOMAR); email: usommer@geomar.de
2. Prof. Klaus Henle, Department of Conservation Biology, Helmholtz Centre for Environmental Research – UFZ;
email: Klaus.Henle@ufz.de
3. Dr. Virgilio Hermoso, Environmental Decision Making Lab, CTFC Forest Sciences Centre of Catalonia ; email:
virgilio.hermoso@gmail.com
4. Dr. Simon Linke, Australian Rivers Institute, Griffith University ; em ail: s.linke@griffith.edu.au Submission Letter
Click here to download Attachment to manuscript
Cover_letter.doc

The work is all original research carried out by the authors. The manuscript has not been published or
presented elsewhere in part or in entirety, and is not under consideration by another journal. It is also not
been previousl y submitted to Landscape Ecology in any form. All the authors have approved the manuscript
and agree d with submission to your journal. There are no conflicts of interest to declare. All sources of funding
are acknowledged in the manuscript .
I look forward to hearing from you.
Yours sincerely,

Anastasia Tsavdaridou