An accepted goal of conservation is to build a conservation network that is resilient to environmental change. Effective corridors should provide suitable and reliable connectivity among habitats for species mobile or less mobile under uncertainty and change. The modelling approach is widely used in this respect, but it is based often on a "static" vision of landscapes (i.e. the cartography of land uses/covers) and does not consider that landscapes (habitats included) are dynamic and so are continuously changing. Indeed, they do change either under different seasonal conditions, or under multiple driving forces like, for instance, climate change. As a result, what we are looking for, i.e. effective corridors, can systematically change on the map, and what is suitable as corridor under certain conditions could not be suitable when season, conditions or the set of focal species are changed. Just because we are not so good in predicting the future and what could be a suitable network sustaining biological diversity and gene exchange, we have to rely on past time series (at a suitable scale) to define the trajectory of every landscape piece to see weather it is predictable or not, that is, if it is persistent or not. Once you get a "predictability" map then you can think of applying different modelling tools to derive, under uncertainty; what possibly could be an effective corridor network for the future. So you could discover that along with "classical" green and blue ways other elements in the landscape could be crucial for the network based on their predictability. You could also discover which unpredictable landscape pieces are crucial for the maintenance of the overall connectivity in the face of climate change and try to transform them in "persistent" through planning and management efforts. See, for instance, the paper "Highlighting order and disorder in social–ecological landscapes to foster adaptive capacity and sustainability" recently appeared in Landscape Ecology.

The same principle should be applied to connectivity for marine systems (see Modeling population connectivity by ocean currents, a graph-theoretic approach for marine conservation appeared in Landscape Ecology). Indeed, for many marine species, population connectivity is determined largely by ocean currents transporting larvae and juveniles between distant patches of suitable habitat. So, connectivity relies on the persistence of ocean currents suggesting areas that might be prioritized for marine conservation efforts and that are working like "stepping stones" in the maintenance of the overall network. On the other hand, you might identify "new" candidate stepping stone areas in case of predicted changes in the oceanic current pattern due to climate change. Unfortunately most of marine biologists and ecologists involved in marine conservation do not consider the importance of ocean currents.

If you are using climate simulations to evaluate the corridors, you should be able to use the historical climate to generate a dataset to use to evaluate current or past corridors. Some examples may be available on databasin.org. If you give me more details, I can probably help you with this more.

Thank you for your promptly answer. Yes we have historical climate and future scenarios (CMIP3), but I want to know if you have some methodology (like papers or something) that describe some evaluating example. I can check in the database. Thank you again.

Specifically what elements/factors do you want to assess/include into the scenario(s)?

For example: modifications in vegetation cover (changes in surface of certain habitat types)?

Thank you Zsolt. Basically we want to evaluate the movement of the species in the landscape, or the structural connectivity (changes in forest, altitudinal connectivity) by easily GIS-measurable elements. We want to replicate some existing methodology for this evaluation. Thanks!

Probably changes in forest-surface is the easiest subject to study. You can check out on the site of the European Environmental Agency (EEA) the results of the program entitled Corine Land Cover. In several countries there were developed analyses of the dynamics of various types of macrohabitats, including the forests. One of these studies were carried out at the beginning of the '90s, the next analyses were performed at the beginning of the 2000s, and nowadays is in preparation the next phase of the same program.

By overlapping satellite images taken in different (successive) years, there was possible to establish where and how many forests were changed (generally it was a reduction of the surfaces covered by natural forests).

A lot of statistics (probably even details on the concrete procedure) You can find on the www-site of EEA...

Thank you, I´m going to check the site, and besides I think that in this same type of research I can use fractal statistics (like fragstats) for try to describe with more accuracy the health of the forests fragments in the landscape. But do you have any idea for evaluate the connectivity in function of the climate change (like altitudinal gradient, or something else?)? Thanks for your answer.

I have to link the connectivity issue to a concrete example, otherwise it will be only a discussion on theoretical aspects. Just as an idea: if a pond became dry (it looses all the water) due to the longer periods with higher temperature, then a newt population using as breeding sites the respective pond will be more isolated from other newt populations (especially if we take into account that these animals live nearby the pond even after the breeding period... when they actually leave the aquatic environment).

Or could be related to the forests: let say that initially You had a compact forest of 1000 hectares populated by I-don't-know-what forest-dependent and not very mobile bird-pairs (each pair needing for example 100 hectares - so in that forest initially You have 10 pairs). In case that 50% of the forest dried up due to the warmer climate, theoretically You will have only 5 pairs, but because their mobility is low, that means that the contact between two neighboring pair will be more difficult (so it could happen that You will have finally only 2 or 3 pairs in the bigger forest patches, and none in the smaller ones).

Do you mean something like these examples?

Our research seeks to evaluate the role of biological corridors for facilitating plant dispersal between protected areas under climate change. On this side we need to assess spatially how will be the plant dispersion under climate change scenarios, for that purpose we have to check the altitudinal, longitudinal and latitudinal ranges in natural forest patches. And besides, I think that we need to evaluate the capability of the plant functional types (PFT) to dispersal in the landscape. I hope that will be more clear now. Thanks.

Our organization has a connectivity specialist. You might check out some of her work: http://consbio.org/products/projects/effects-of-climate-and-vegetation-on-the-current-and-future-distribution-of-martens-and-fishers-in-the-sierra-nevada-cal and http://consbio.org/products/projects/california-connectivity.

Dear Juan,

GIS tools you can find, e.g., at: http://corridordesign.org/. Using habitat modelling you can integrate aspects of land use and climate change. Tools for the analysis of connectivity you can find, e.g., at: http://www.conefor.org/ and http://www.circuitscape.org/ and http://forest.jrc.ec.europa.eu/download/software/guidos/. Beside this you can use individual based modelling (movement) approaches to compare scenarios like, e.g., http://www.nrel.colostate.edu/projects/starmap/funconn_index.htm or http://www.plosone.org/article/info%3Adoi%2F10.1371%2Fjournal.pone.0022355. Please see also: http://etd.lib.clemson.edu/documents/1285779072/Perkl_clemson_0050D_10717.pdf

Best, Reinhard

Thanks for all your help. I also find in an article (Imbach et ál. In press) that altitudinal range, altitude and corridor`s area are independent variables that cab be use to evaluate the effectiveness of corridors before climate change. I must review all your links. Thanks again for your help.

Cheers, Jk

Also check out the climate corridors work carried out in Washington state, USA: http://waconnected.org/climate-change-analysis/

Tools available on the webpage too, though the climate corridors one is still being developed.

Good luck,

Effective corridors provide suitable habitat for species you hope to provide connectivity for. For mobile species those habitat considerations may be very broad, but for less mobile species corridors may need to include habitat of sufficient quality and quantity to have that species maintain populations within the corridor. Once you determine the corridor habitat needs for the species you are concerned about, you can then use a GIS based habitat suitability - niche modeling tools such as MAXENT or Mahalanobis to characterize the distribution and extent of "suitable corridor habitat" currently available. The next step then could be to shift the climate variables in the underlying GIS database-map to reflect expected conditions under one or more climate change scenarios. Then when you re-project your corridor habitat model over the new climate-shifted landscape you can identify if and where suitable corridor habitat will occur in the future.

I suggest you to model some (current and future) ensambles of your species distribution (bioMod2, or mMWeb).Then model Land use and land cover changes Clark Labs´Land Change Modeler) for the same time frame in which you modeled your species. And finally define (and compare) current and future corridors

You may want to check the LARCH Ecoplanit model from Alterra. It is free available on the website. The model works under ARCGis and uses vector maps. The quality of the vegetation or land use map, as well as the usefulness of the map for the studied species, defines how accurate the result will be.

http://www.wageningenur.nl/nl/Expertises-Dienstverlening/Onderzoeksinstituten/Alterra/Faciliteiten-Producten/Software/LARCH.htm

The model assesses population viability for different species (LARCH), but also landscape connectivity (LARCH Scan). This is based on an algorithm, which depends on the species requirement, carrying capacity of a cell, and landscape resistance.It calculates landscape connectivity for a grid, and visualizes best corridors in the landscape. Also, it can show if corridors may function for a species.

The model was used in many different countries in Europe, and we published a paper in Conservation Biology. At the moment we are using the model for a study on landscape connectivity in Israel.

Article Designing a Coherent Ecological Network for Large Mammals in...

An accepted goal of conservation is to build a conservation network that is resilient to environmental change. Effective corridors should provide suitable and reliable connectivity among habitats for species mobile or less mobile under uncertainty and change. The modelling approach is widely used in this respect, but it is based often on a "static" vision of landscapes (i.e. the cartography of land uses/covers) and does not consider that landscapes (habitats included) are dynamic and so are continuously changing. Indeed, they do change either under different seasonal conditions, or under multiple driving forces like, for instance, climate change. As a result, what we are looking for, i.e. effective corridors, can systematically change on the map, and what is suitable as corridor under certain conditions could not be suitable when season, conditions or the set of focal species are changed. Just because we are not so good in predicting the future and what could be a suitable network sustaining biological diversity and gene exchange, we have to rely on past time series (at a suitable scale) to define the trajectory of every landscape piece to see weather it is predictable or not, that is, if it is persistent or not. Once you get a "predictability" map then you can think of applying different modelling tools to derive, under uncertainty; what possibly could be an effective corridor network for the future. So you could discover that along with "classical" green and blue ways other elements in the landscape could be crucial for the network based on their predictability. You could also discover which unpredictable landscape pieces are crucial for the maintenance of the overall connectivity in the face of climate change and try to transform them in "persistent" through planning and management efforts. See, for instance, the paper "Highlighting order and disorder in social–ecological landscapes to foster adaptive capacity and sustainability" recently appeared in Landscape Ecology.

The same principle should be applied to connectivity for marine systems (see Modeling population connectivity by ocean currents, a graph-theoretic approach for marine conservation appeared in Landscape Ecology). Indeed, for many marine species, population connectivity is determined largely by ocean currents transporting larvae and juveniles between distant patches of suitable habitat. So, connectivity relies on the persistence of ocean currents suggesting areas that might be prioritized for marine conservation efforts and that are working like "stepping stones" in the maintenance of the overall network. On the other hand, you might identify "new" candidate stepping stone areas in case of predicted changes in the oceanic current pattern due to climate change. Unfortunately most of marine biologists and ecologists involved in marine conservation do not consider the importance of ocean currents.

Ciao Giovanni,

Correct, there are many uncertainties in landscape trajectories, and it is difficult to model all. Although I recall that colleagues have experimented with random habitat change models. But, an alternative is to have different scenario's of course, for wich you analyse the landscape connectivity (at least, that is what we do with LARCH, e.g. 5 scenario's we did for the Vistula River in Poland).

However, another issue is, what is the function of the corridor. Is it indeed a matter of gene exchange, than one animal crossing per year could be sufficient. Or is it annual migration, or to facilitate foraging in other habitat? We differentiated in a brochure on European corridors the different functions of corridors for species.

And, here the spatial analysis is of importance: are areas large enough to host populations of species, and are metapopulations meeting the criteria for a viable population? Based on that, you may decide that corridors are essential for the viability of a population.

But, it remains that the change over time, e.g. climate change, is hard to model. But in some cases you may experiment with e.g. lower carrying capacities of habitat, and see what its effect is on the populations...

The following paper from my colleagus may be of interest for you too:

Vos, C. C., Berry, P., Opdam, P., Baveco, H., Nijhof, B., O’Hanley, J., Bell, C. and Kuipers, H. (2008) 'Adapting landscapes to climate change: examples of climate-proof ecosystem networks and priority adaptation zones', Journal of Applied Ecology, 45, 1722-1731

Hello Juan,

In Luxembourg and Belgium, to assess the quality of riverbank, we used a methodology based on a GIS application (see the publication below). In Germany, the Otterzentrum has made a publication on corridors called OHNE (Otter Habitat Network Europe) (Volume 15) which is also based on a GIS study. You can buy this book by the Otterzentrum (see the Web with the link: http://xtc.dos-kunstundnatur.de/index.php?cat=c2_B-cher.html&page=1). Good luck in your work in Costa Rica.

Gérard

I agree with those who are pointing to the the need to be explicit about what groups of plants and animals you are envisioning "corridors" to sustain, and what the functional use of the corridors is, or would be. Are you talking about sustaining dispersal, maintaining annual or seasonal migrations, or providing for future intergenerational migration that might track interdecadal changes in climate gradients, or all of these? While species and assemblages may share the same regional landscape, not all "see" the same geography. At the crudest level, corridors designed for upland terrestrial species may not be functional for freshwater species or riparian or wetland associates. On the other hand they potentially could be resolved, if criteria for definition and design criteria are forged accordingly. In general we need to get much more astute about integrating the needs of terrestrial and freshwater species in conservation area design and assessment--before we pull a GIS routine off the shelf to run an analysis.

Try this one

http://www.circuitscape.org