ecology

  1. B

    Which stats test should I use?

    I have an experiment to look at habitat preferences of beetles and the effect of competition. In the first test, a beetle is on his own in an arena and I measured the % of time he spends in each of THREE types of habitat (open, bush and underground). I repeat this experiment with several...
  2. P

    Chi Square test

    Hi Guys, Hope you all are doing well. I am very new to statistics and I have a little doubt regarding what test to use to analyze my data. I have some bacterial population counts (4 bacterial species) for 4 different geographical sites. I wish to see the association between bacterial prevalence...
  3. A

    Comparing an ecological subsample to population

    I have 2 batches of tree species and abundance data collected for a city. The difference between them is the sampling strategy - one was random unstratified, and the other was stratified and clustered. At a glance the species mixes and relative abundances are fairly similar but i want to test...
  4. F

    Bird Community Ecology - BACI experiment

    Greetings! I'm currently trying to investigate the impact of an event on the bird community of a National Park on my country. For that I have collected data in the BACI format (Before After Control Impact) and I would like to know what is the best way to analyze it. I have richness and...
  5. S

    Suggestions for model fit with unusual data set?

    Good morning, I'm struggling to fit a satisfactory model to a data set I have resulting from a systematic review. I performed a systematic review of estimated $ valuations of grasslands and the services they provide. All grasslands provide all services, but some studies only value one of...
  6. S

    Comparing categorical and numerical results simultaneously

    Hi all, This question is in regards to options for analysing a dataset. I have a dataset where we have 23 video clips that have been treated using three different algorithms to change how each clips looks. Each treatment has then been viewed by a number of scientists to try and identify the...
  7. R

    Ecology: how to compare "intrinsic growth rates" (r)

    Hi everybody, I would like to know how to statistically compare different "intrinsic growth rates", most of the times named "r", belonging to different populations. It's a ecotoxicological experiment with these two simple variables: 1) time (days, from 0 to 21) 2) live offspring (total...
  8. S

    Classification model according to multivariate presence/absence dataset

    Hi there! I am currently working on the analysis of a two part experiment looking at bacterial communities in diatoms, under different temperatures. It is quite a complicated one, and I was hoping I could get some input on how to analyze it. First, however, let me explain how it was...
  9. D

    Error in creating a raster stack - any suggestions on how to fix the problem?

    Hi I am trying to create a raster stack of several ASCII files for an environmental variable. This is what I have done so far: >files <- list.files(path=paste(system.file(package="dismo"), '/temperature', sep=''), pattern='asc', full.names=TRUE ) >files #gives me a list of the files...
  10. A

    I don't understand the results of my ANOVA

    I have run general linear model (ANOVA) in SPSS to test whether habitat type (2 categories) and habitat disturbance (2 categories) have an effect on the size of deer groups. When I use the data for ALL groups (including mixed sex groups, all male groups and all female groups - they're all under...
  11. U

    2 independent categorical variables. What test do I use?

    Sorry if this has been asked before, if it has I couldn't find it. Also excuse me if I mix up terms, I'm a bit of a novice. My experiment had two categorical independent variables. 1.)The feeding history of the fly (protein fed or sugar fed) 2.)The type of substrate tested for preference...
  12. D

    Help analyzing bird migration patterns?

    Hi. I am trying to analyze data I have on bird migration and am stuck on what I need to do. Basically, I have the maximum abundance of birds seen per week for 10 weeks for 4 sites within a location, for 5 different species, and over the course of 5 years. So for one year, the abundance...
  13. trinker

    Interview your friendly Ecologist/Archaeologist

    While helping Bugman and gianmarco with respective problems I became interested in the work they do. I love visualization and I love geographical plotting. But I'm in a field (literacy) that really isn't about geo-spatial representation of data. But then I had a though. I remembered seeing...
  14. R

    Not sure about what test....

    Hi everybody, I need to analyze possible differences in the invertebrates populations living in 3 different environmental treatments (3 plus 3 replica). A subsample containing invertebrates species is taken every week for a total of 10 sampling events. Therefore 10 invertebrates populations...
  15. T

    Can an explanatory variable be both a random and fixed effect simultaneously?

    Hello, and thank you for reading. I am trying to test for what environmental variables (3 continuous distance variables e.g. distance from nearest village) influence 1) species richness at the site level (continuous variable) and 2) community composition at the site level (coordinates of...
  16. T

    Nested test to remedy pseudoreplication

    Hello and thanks for taking the time to read this. Data structure: I have two datasets from two protected areas that differ in protection status. Both areas contain 43 and 37 sites each. Question: I would like to know which test would be the best for testing whether the PA status has...
  17. S

    Analysing relationships between numerical data and non- numerical data.

    Hi all, new user here hoping to become part of the community, I have recently purchased a book reccommended to me - Discovering statistics using SPSS (Field, 2013) with a view to knuckling down on statistical analysis of my data that i have collected for a Master's project. I have various...
  18. A

    Is my variable count or measurement and what statistical model would be best?

    I am trying to assess the fine-scale spatial distribution of tadpoles along a depth gradient in relation to abiotic and biotic factors -- and am having great difficulty in determining the best statistical test (Chi square VS ANOVA) to use BECAUSE I cannot determine what kind of data I have...
  19. C

    Repeated measures or not?

    Hi All, I sampled crickets weekly over 5 weeks from the same population, and measured their body size. Half of the crickets were taken from predator's nests (sampled within a day of being caught), and half were sampled directly from their natural habitat. My research question is: are predators...
  20. B

    Help on which tests to apply to landscape ecology data

    I am looking for help on which stats to apply to my landscape ecology data. I am attempting to demonstrate that a connectivity index is able to detect relevant changes in the amount and distribution of habitat within a landscape. Based on an existing patch of land an ecosystem simulation model...