The Potential Connectivity of Waterhole Networks and the Effectiveness of a Protected Area under Various Drought Scenarios

Landscape connectivity is considered a priority for ecosystem conservation because it may mitigate the synergistic effects of climate change and habitat loss. Climate change predictions suggest changes in precipitation regimes, which will affect the availability of water resources, with potential consequences for landscape connectivity. The Greater Calakmul Region of the Yucatan Peninsula (Mexico) has experienced a 16% decrease in precipitation over the last 50 years, which we hypothesise has affected water resource connectivity. We used a network model of connectivity, for three large endangered species (Baird’s tapir, white-lipped peccary and jaguar), to assess the effect of drought on waterhole availability and connectivity in a forested landscape inside and adjacent to the Calakmul Biosphere Reserve. We used reported travel distances and home ranges for our species to establish movement distances in our model. Specifically, we compared the effects of 10 drought scenarios on the number of waterholes (nodes) and the subsequent changes in network structure and node importance. Our analysis revealed that drought dramatically influenced spatial structure and potential connectivity of the network. Our results show that waterhole connectivity and suitable habitat (area surrounding waterholes) is lost faster inside than outside the reserve for all three study species, an outcome that may drive them outside the reserve boundaries. These results emphasize the need to assess how the variability in the availability of seasonal water resource may affect the viability of animal populations under current climate change inside and outside protected areas.

[1]  G. W. Tanner,et al.  Home Range and Habitat Preferences of White-Lipped Peccaries (Tayassu pecari) in Calakmul, Campeche, Mexico , 2009 .

[2]  Jordi Bascompte,et al.  Spatial network structure and amphibian persistence in stochastic environments , 2006, Proceedings of the Royal Society B: Biological Sciences.

[3]  Martyn L. Gorman,et al.  A potential habitat network for the Eurasian lynx Lynx lynx in Scotland , 2008 .

[4]  Yolanda F. Wiersma,et al.  A new measure of longitudinal connectivity for stream networks , 2008, Landscape Ecology.

[5]  Andrew Gonzalez,et al.  The disentangled bank: how loss of habitat fragments and disassembles ecological networks. , 2011, American journal of botany.

[6]  Marie-Josée Fortin,et al.  From Graphs to Spatial Graphs , 2010 .

[7]  B. Schmook,et al.  Sequías en el sur de la península de Yucatán: análisis de la variabilidad anual y estacional de la precipitación , 2012 .

[8]  Eric J. Pedersen,et al.  Searching in heterogeneous and limiting environments: foraging strategies of white-lipped peccaries (Tayassu pecari) , 2012 .

[9]  S. Saura,et al.  Comparison and development of new graph-based landscape connectivity indices: towards the priorization of habitat patches and corridors for conservation , 2006, Landscape Ecology.

[10]  C. Wright,et al.  Spatiotemporal dynamics of prairie wetland networks: power-law scaling and implications for conservation planning. , 2010, Ecology.

[11]  M. Holmgren,et al.  Herded cattle and wild grazers partition water but share forage resources during dry years in East African savannas , 2009 .

[12]  J. Ragle,et al.  IUCN Red List of Threatened Species , 2010 .

[13]  S. Chamaillé‐Jammes,et al.  Fluctuations in abundance of large herbivore populations: insights into the influence of dry season rainfall and elephant numbers from long‐term data , 2008 .

[14]  D. Conde,et al.  Jaguars on the move: modeling movement to mitigate fragmentation from road expansion in the Mayan Forest , 2011 .

[15]  Michel Baguette,et al.  Importance of Habitat Quality and Landscape Connectivity for the Persistence of Endangered Natterjack Toads , 2008, Conservation biology : the journal of the Society for Conservation Biology.

[16]  Timothy H. Keitt,et al.  LANDSCAPE CONNECTIVITY: A GRAPH‐THEORETIC PERSPECTIVE , 2001 .

[17]  Jon Norberg,et al.  A Network Approach for Analyzing Spatially Structured Populations in Fragmented Landscape , 2007, Landscape Ecology.

[18]  R. Owen-Smith,et al.  Megaherbivores: The Influence of Very Large Body Size on Ecology , 1990 .

[19]  Andrew Fall,et al.  A domain-specific language for models of landscape dynamics , 2001 .

[20]  J. Metzger,et al.  The structural connectivity threshold : an hypothesis in conservation biology at the landscape scale , 1997 .

[21]  Robin Abell,et al.  Terrestrial Reserve Networks Do Not Adequately Represent Aquatic Ecosystems , 2010, Conservation biology : the journal of the Society for Conservation Biology.

[22]  S. Schneider,et al.  Climate Change 2007 Synthesis report , 2008 .

[23]  J. R. Eastman,et al.  Land change in the southern Yucatán and Calakmul biosphere reserve: effects on habitat and biodiversity. , 2007, Ecological applications : a publication of the Ecological Society of America.

[24]  C. Pringle.  HYDROLOGIC CONNECTIVITY AND THE MANAGEMENT OF BIOLOGICAL RESERVES: A GLOBAL PERSPECTIVE , 2001 .

[25]  Raja R. Sengupta,et al.  A spatial decision support system to identify species-specific critical habitats based on size and accessibility using US GAP data , 2004, Environ. Model. Softw..

[26]  C. Gómez‐Rodríguez,et al.  Mediterranean temporary ponds as amphibian breeding habitats: the importance of preserving pond networks , 2009, Aquatic Ecology.

[27]  S. Hannon,et al.  Critical thresholds associated with habitat loss: a review of the concepts, evidence, and applications , 2010, Biological reviews of the Cambridge Philosophical Society.

[28]  H. Andrén,et al.  Effects of habitat fragmentation on birds and mammals in landscapes with different proportions of suitable habitat: a review , 1994 .

[29]  Ruth DeFries,et al.  Ecological mechanisms linking protected areas to surrounding lands. , 2007, Ecological applications : a publication of the Ecological Society of America.

[30]  Jean Clobert,et al.  Informed dispersal, heterogeneity in animal dispersal syndromes and the dynamics of spatially structured populations. , 2009, Ecology letters.

[31]  Paula L. Enríquez,et al.  Influencia de la disponibilidad de agua en la presencia y abundancia de Tapirus bairdii en la selva de Calakmul, Campeche, México , 2012 .

[32]  Influencia de la disponibilidad de agua en la presencia y abundancia de Tapirus bairdii en la selva de Calakmul, Campeche, México Influence of water availability in the presence and abundance of Tapirus bairdii in the Calakmul forest, Campeche, Mexico , 2012 .

[33]  Erik Andersson,et al.  Practical tool for landscape planning? An empirical investigation of network based models of habitat fragmentation , 2009 .

[34]  R. Pachauri.  Climate change 2007. Synthesis report. Contribution of Working Groups I, II and III to the fourth assessment report , 2008 .

[35]  S. Schneider,et al.  A contribution of Working Groups I, II and III to the Third Assessment Report of the Intergovernment Panel on Climate Change , 2001 .

[36]  Santiago Saura,et al.  Ranking individual habitat patches as connectivity providers: Integrating network analysis and patch removal experiments , 2010 .

[37]  Andrew Fall,et al.  Patch-based graphs of landscape connectivity: A guide to construction, analysis and application for conservation , 2011 .

[38]  J. Clobert,et al.  Resource variability, aggregation and direct density dependence in an open context: the local regulation of an African elephant population. , 2008, The Journal of animal ecology.

[39]  C. Vaughan,et al.  Home Range, Habitat Use, and Activity of Baird's Tapir in Costa Rica1 , 2002 .

[40]  Santiago Saura,et al.  A new habitat availability index to integrate connectivity in landscape conservation planning : Comparison with existing indices and application to a case study , 2007 .

[41]  Pedro Segurado,et al.  Using spatial network structure in landscape management and planning: A case study with pond turtles , 2011 .

[42]  J. Fernández-Palacios,et al.  Crocodiles Crocodylus niloticus as a focal species for conserving water resources in Mauritanian Sahara , 2008, Oryx.

[43]  J. Prieto,et al.  Reconocimiento geomorfológico e hidrográfico de la Reserva de la Biosfera Calakmul, México , 2002 .

[44]  Stuart L. Pimm,et al.  Fences and artificial water affect African savannah elephant movement patterns , 2009 .

[45]  J. Rogan,et al.  Mapping seasonal trends in vegetation using AVHRR-NDVI time series in the Yucatán Peninsula, Mexico , 2012 .

[46]  Taku Kadoya,et al.  Assessing functional connectivity using empirical data , 2008, Population Ecology.

[47]  T. O. Crist,et al.  Critical Thresholds in Species' Responses to Landscape Structure , 1995 .

[48]  Justin M. Calabrese,et al.  A comparison-shopper's guide to connectivity metrics , 2004 .

[49]  Santiago Saura,et al.  A common currency for the different ways in which patches and links can contribute to habitat availability and connectivity in the landscape , 2010 .

[50]  M. Tobler.  The ecology of the lowland tapir in Madre de Dios, Peru: Using new technologies to study large rainforest mammals , 2008 .