re: 1. Sampling vegetation for wildlife habitat purposes (2)
Amy, Just a couple of thoughts: your 15m radius plots may be too small to key into some of the important habitat/vegetation structure elements that are important for foraging - habitat elements important for owl foraging include those for both the predator AND the prey. Also, I've attached a data sheet that we use on our statewide Alaskan Landbird Monitoring Survey (ALMS) - the last two pages of the .pdf are the habitat forms. Incidentally, ALMS is a cooperative effort subscribed to and supported by all the federal and state land management agencies in the Alaska. We sample a 50m radius about our points, and fill out a separate series of forms for every habitat that occurs within the circle. We've devised rules and definitions about how and when to break out patches as distinct habitats as opposed to lumping them together as a "habitat mosaic." We also have guidelines on minimum size for what is deemed a "habitat patch." We use a modification of the Relevee / Braun-Blaunket method for vegetation description - a method well suited to capturing the definitive vegetation elements without spending a great deal of time on methods such as line transects, quadrats, pin-frames, etc. all of which are very time consuming, and though quite precise they are only accurate descriptors if sufficient replicates are conducted. The method we use is also well suited to non-botanists because the classifications are based primarily on dominant species of each veg layer. The result is a vegetation sampling regime that is fine enough in resolution to accurately describe the various habitats, but is gross enough to be useful for modeling with remotely sensed data; it is relatively quick to perform, and is friendly to non-botanically minded field techs (with a little basic training). If you'd like more information, I can send you the protocols which describe our habitat sampling schema. Cheers, and best of luck David Tessler -- David F. Tessler Regional Wildlife Biologist, Nongame Program Alaska Department of Fish and Game Division of Wildlife Conservation 333 Raspberry Road Anchorage, Alaska 99518 Phone: (907) 267-2332 Fax: (907) 267-2433 email: [EMAIL PROTECTED] web: http://www.wildlife.alaska.gov/index.cfm?adfg=nongame.staff ECOLOG-L automatic digest system wrote: >There are 2 messages totalling 101 lines in this issue. > >Topics of the day: > > 1. Sampling vegetation for wildlife habitat purposes (2) > >---------------------------------------------------------------------- > >Date: Sat, 2 Jun 2007 10:55:56 -0400 >From: Michael Fuller <[EMAIL PROTECTED]> >Subject: Re: Sampling vegetation for wildlife habitat purposes > >Amy, >Sounds like an interesting field situation. if you need to quantify >vegetation patchiness within your 15m circular plots, then I >recommend you do some exploratory analysis first before designing >your protocol. For example, you could perform multiple variogram >analyses, using a range or sequence of quadrat sizes (e.g. 10, 20, >30, 40cm, etc) to determine the scale at which patches of herbaceous >vegetation are most apparent. This would allow you to choose the most >suitable quadrat size for your sampling protocol. Also, you may need >to divide your protocol into forested, meadow, and riparian classes >as the processes that determine patch size are likely to be different >for the different vegetation types. > >Have you considered that physiognomy may be more important to owl >foraging than the herbaceous community composition? Does the owl use >forest trees as a perch to scan for small mammals in the meadows? If >so, then might not average tree height or distance between nearest >neighbors be important variables? Likewise, there may be a minimum >(or optimal) meadow area for the owls (related to prey carrying >capacity or length of the field of vision of the predator). Another >possibility is that foraging quality is governed by the length of the >forest-meadow ecotone. > > From your description it seems you have yet to decide on how you >will analyze your data statistically. I recommend you determine this >first, and let your decision guide your data collection protocol. > >I recommend you look at the following texts for additional guidance >on measuring and analyzing vegetation patterns: >* Dale, MR.T. 1999. Spatial pattern analysis in plant ecology. >Cambridge University Press, New York. >* Legendre and Legendre. 1998. Numerical Ecology. Elsevier Scientific >Publ. Co. Amsterdam. > >Good luck with your field techs! >Mike > >Amy Williams wrote: > > >>I am putting together a vegetation protocol for measuring plant >>communities >>and general habitat characteristics associated with known >>observations of a >>Sierra Nevada owl. My question is: how best can one capture patchy >>vegetation in 15-m radius circular plots (associated with foraging >>points)? >>Foraging habitat for this owl, while often at meadow edges, is quite >>variable (e.g. sometimes in very small drainages further in the >>forest, on >>dry upland logged areas, larger riparian non-meadow areas, etc.). >>Keeping in >>mind that vegetation within the plot is not homogeneous (the plot >>being >>often, but not always, half meadow and half forest) is there a >>statistically >>sound method for capturing vegetation, especially herbaceous? I >>would like >>the protocol to be user-friendly for non-botanist field crew. >>Because of >>this I would like to avoid visual cover estimation or any other >>subjective >>method of data collection. Would it be feasible to use a 10-cm square >>sub-quadrat and record presence/absence of individual species (or >>where >>botany skills falter, type: forb, grass, sedge) and average height >>class at >>each meter point on each of the four cardinal direction transects >>(= 60 >>points)? >> >> > >------------------------------ > >Date: Sat, 2 Jun 2007 11:57:37 -0700 >From: Amy Williams <[EMAIL PROTECTED]> >Subject: Re: Sampling vegetation for wildlife habitat purposes > >Thank you all for your many insightful responses. Perhaps I can clarify a >little bit. The research is already designed to gather plot-level >information on vegetation physiognomy (canopy height and density, DBH, tree >condition, percent of plot that is meadow, forest, bare ground, downed wood, >etc.), as well as soil attributes and hydrology. In addition, I did intend >to use the 10-cm square sub-quadrats to represent single points to gather >presence/absence of either species or type (sedge, forb, grass), and average >height. Is there a systematic way to place a large number of these in a 15-m >square circular plot, besides limiting them to orthogonal cross-transects? I >will make sure to consult the texts recommended to me; maybe I will find my >answers there. > >Again, thank you for the help! > >------------------------------ > >End of ECOLOG-L Digest - 1 Jun 2007 to 2 Jun 2007 (#2007-151) >************************************************************* > > > -- David F. Tessler Regional Wildlife Biologist, Nongame Program Alaska Department of Fish and Game Division of Wildlife Conservation 333 Raspberry Road Anchorage, Alaska 99518 Phone: (907) 267-2332 Fax: (907) 267-2433 email: [EMAIL PROTECTED] web: http://www.wildlife.alaska.gov/index.cfm?adfg=nongame.staff -- David F. Tessler Regional Wildlife Biologist, Nongame Program Alaska Department of Fish and Game Division of Wildlife Conservation 333 Raspberry Road Anchorage, Alaska 99518 Phone: (907) 267-2332 Fax: (907) 267-2433 email: [EMAIL PROTECTED] web: http://www.wildlife.alaska.gov/index.cfm?adfg=nongame.staff
