WorldClim-missing future bioclimatic data for CMIP6

[Tim Gregorčič]

Dear all,

I am trying to download future bioclimatic data for CMIP6 from WorldClim (2081-2100) for my SDM research using Maxent. Unfortunately, the downloaded folder does not contain 19 bioclimatic variables, but only one. I read the papers where these data were downloaded normally in the near past so I want to ask you whether some of you have these data (for any climate model) on your computers and would want to share them with me.

Thank you for your time and answers.

Yours Sincerely,

Tim Gregorcic 

[Bede-Fazekas Ákos]

Dear Tim,
does the folder contain one raster file or one zipped file that contains several rasters? I assume the latter. In this case, you should firstly unzip the file, and then use the rasters in MaxEnt.
Or, alternatively, you can download the raw monthly data and calculate the bioclimatic variables.
HTH,
Ákos Bede-Fazekas
Centre for Ecological Research, Hungary

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[Pritam chhetri]

Hi Tim,

I recently worked with the CMIP6 data. 

After you download the data you have to extract it and yes you will get only one tif file. The file you get will have 19 bands in it and you have to extract it in R using the following codes.

s1<-brick("wc2.1_2.5m_bioc_BCC-CSM2-MR_ssp245_2021-2040.tif")

for (i in 1:nlayers(s1)){

  r<-s1[[1]]

  layer=paste("bioclim_",i,"_.tif",sep="")

  writeRaster(r, layer)

}

Regards

Pritam

[Belay Ejigu]

You can download from this link: www.worldclim.org. All are available as 20 years average.

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[Belay Ejigu]

Dear Ákos Bede-Fazekas, 

I, from my side , have one question that I couldn't answer over a long time, maybe if you got the secret algorithm behind maxent model,  how it determines the similarity between  current and future environmental variables when we do future projections?. In other ways, how does it determine the probability of current and future environmental variables at a given grid cell?. Is paired independent t test used in maxent model to calculate the significance difference between current and future environmental variables at a single grid cell or how?

[Gafarou AGOUNDE]

I faced this issue recently. But l solved it through Arcgis. 

Management of Wildlife, Protected Areas and Rangeland | MSc, University of Abomey-Calavi, Benin republic. Phone number:(+229)96692934

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[Belay Ejigu]

Gafarou AGOUNDE; yeah, you are wright. The asked issue can be solved using Arc GIS or Quantum GIS or; 

i hope it can also be solved with advanced programming technology like Python. 

Nothing is impossible nowadays!. 

Many god blesses!

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[Bede-Fazekas Ákos]

Dear Belay,
please open a new thread/topic if you have a question not connecting to the original post.
There are several papers that descibe the core algorithm of maximum entropy, e.g.:
Elith J, Phillips SJ, Hastie T, Dudík M, Chee YE, Yates CJ (2011): A statistical explanation of MaxEnt for ecologists. Diversity and Distributions 17(1): 43–57. DOI: 10.1111/j.1472-4642.2010.00725.x.
HTH,
Ákos

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[Gafarou AGOUNDE]

Of course. Maybe he is not too confortable with R software that is why l proposed an alternative solve. I also used the script you sent and it worked well.

Thanks my friend

Management of Wildlife, Protected Areas and Rangeland | MSc, University of Abomey-Calavi, Benin republic. Phone number:(+229)96692934

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[Belay Ejigu]

Yeah, dear thanks a lot. I was reading these papers and others, have been watching several tutorial videos, but i have been confused with the concepts that i was gathering from different sources, especially on the issues like calculating lambda value for each variables, why it converts raw probability (F(x) and F(x1)), the value of calculating gain and how or why it gives us the summarized values of probabilities for different variables used in the maxent model i.e. the final output that maxent model gives us to create map or do further analysis with the algorithm:exp (lambda1 xf1 + lambda2 x f2+......+lambdan x fn).

Another is, how to consider other very important life processes in the maxent model that can further help in different decision making processes like adjusting adaptation strategies to future climate change, etc.

Thanks a lot Ákos Bede-Fazekas!. 

I always appreciate your understanding of this very interesting method of modeling entropy.

Stay safe and blessed!

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