# Machine learning to find drivers of an event with presence-only data (no absence)

I have some ecological data on the confirmed presence of a certain animal. I have data on the:

Date
Simple metrics on the animal
A complete weather record for the site.


I'm assuming the presence of this animal is driven by weather events, and that the metadata about the site may be an important factor for patterns in the data. What my data ends up looking like is this.

#Date of observation
Date<-as.POSIXct(c("2015-01-01","2015-01-11","2015-01-19","2015-02-04","2015-02-12","2015-02-23","2015-04-01","2015-04-10","2015-04-16","2015-04-20"))

Size<-c(1,1,1,2,2,3,4,1,2,5)
Color<-c("B","B","R","R","R","R","B","B","B","Y" )
Length<-c(1,10,12,4,5,2,1,2,7,12)

#Weather Data
AirTempDayOf<-c(20,40,20,23,24,25,24,25,25,22)
WindSpeedDayOf<-c(2,3,2,3,4,3,2,3,4,5)
AirTempDayBefore<-c(21,40,22,23,24,24,24,27,25,22)
WindSpeedDayBefore<-c(2,5,2,6,4,3,6,3,2,5)
AirTemp2DayBefore<-c(21,45,22,23,34,24,24,23,25,23)
WindSpeed2DayBefore<-c(8,5,3,6,4,7,6,3,2,6)

Type<-c("Forest","Forest","Forest","Forest","Forest","Beach""Beach""Beach","Swamp","Swamp")
Population<-c(20,30,31,23,32,43,23,43,23,33)
Use<-c("Industrial","Commercial","Industrial","Commercial","Industrial","Commercial","Industrial","Commercial","Industrial","Commercial",)

DF<-data.frame(Date,Size,Color,Length,AirTempDayOf, WindSpeedDayOf,AirTempDayBefore,WindSpeedDayBefore,AirTemp2DayBefore,WindSpeed2DayBefore)


What I don't have is absence data, so I can't make any assumptions about when an organism was not at the site. I'd like to look for patterns in weather that my be driving the arrival of this organism, but all I have is data on when the organism was spotted.

Is it possible to apply some sort of machine learning to look for patterns that may be driving the arrival of this animal? If I don't have absence data, I'm assuming I cant. I've looked into pseudo-absence models, but I don't know how they might apply here.

If I can't use machine learning to look at drivers for the presence of these animals, is it possible to use ML to look at possible weather patterns that may be associated with some of the metadata about the site? For example, weather patterns that may be associated with Forrest vs Beach habitats?

I usually use R for my stats, so any answers including R packages would be helpful.

Also, note that this is just an example dataset above. I don't expect to find any patterns in the above data, and my actual dataset is much larger. But any code developed for the above data should be applicable

• Have you made regular observations? If so, the dates that are not recorded could be assumed to be Absences. – Rory Alsop Apr 12 '19 at 13:00
• The observations are not regular, so I can't assume anything about dates not in the dataset – Vint Apr 12 '19 at 13:02