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Surveying, Monitoring and Predicting the Occurrence and Spread of Native and Non-Native Plant Species at Idaho National Laboratory Site

Management of both non-indigenous plant species (NIS) and rare plants species (RPS) is a high priority in many managed forests, wildlands and rangeland areas. However, rarely do either public or private agencies have sufficient resources to manage all NIS or conserve all RPS. Neither do agencies have sufficient information on the potential impacts of future anthropogenic development. Therefore, a better understanding of the temporal and spatial processes which drive both NIS and RPS population distributions and dynamics is required to improve management effectiveness and efficiency. The difficulty in increasing our knowledge of NIS and RPS population dynamics in the sagebrush steppe plant community is that they occur with low frequency on the landscape and can be difficult to detect because they are similar in morphology to the co-occurring species. By using knowledge of probable routes of introduction for the NIS, and particular habitat requirement etc. for the RPS, appropriate survey methods can be developed. Repeated sampling can then help to elucidate the spatiotemporal dynamics of select populations. From such data predictive occurrence maps can be generated for the current landscape, but also for a range of future scenarios including anthropogenic development. Incorporating the information into a decision support management prioritization framework can help resource managers prioritize populations to manage and help evaluate the potential impacts of different disturbance scenarios to minimize the negative (RPS) or positive (NIS) impacts on plant population dynamics.

Objectives
The goal of this study is to determine the current distribution of NIS and RPS on the INL Site and predict the potential spatial and temporal metapopulation dynamics of these species to help inform management and future development decisions. Specific objectives include:

• Evaluate existing data on NIS and RPS at the INL Site and assemble spatial environmental data for further modeling exercises

• Conduct a NIS and RPS field survey of all NIS and RPS in the INL Site CMP Development Zone

• Develop probability of occurrence models for NIS and RPS and generate maps from these models

• Repeat transects in multiple years to calculate Markov transition probabilities and predict further invasion or extinction dynamics of NIS and RPS throughout the INL Site Development Zone

• Simulate metapopulation dynamics for a range of development scenarios at the INL using the multistate Markov transition probabilities.

Accomplishments through 2009

This project commenced in May of 2009. In April of 2009, environmental data (primarily GIS layers) were secured from Stoller and stratified random transects were delineated throughout the CMP Development Zone within a GIS. These transects originated on roads or facility margins and traveled 2 km away from the facility or road. Transects were in pairs, with the location of a pair randomly selected to be up to 500 m away from each other. In June and July, approximately 37 transects were completed. NIS and RPS presence and absence was recorded along each transect. This represented approximately 0.315 percent of the total area of the CMP Development Zone. On twenty of these transects the presence and abundance of all plant species were recorded to assess plant biodiversity. The distance between the 10 transect pairs was also sampled for biodiversity, that is 10 additional transects between 50m and 500m long were sampled. Five of the 37 transects were repeated in late July to determine the within-season variability in NIS occurrence as precipitation in June and July of 2009 exceeded the 30-year average threefold.
 

These data were processed and imported into a GIS, some different analysis methods explored and generalized linear models of the more frequent NIS generated. These preliminary models have been used to inform the sampling for 2010.

Results

Preliminary survey
Seventeen NIS were observed in the 37 presence/absence transects. A further five NIS were observed, for a total of 1-5 individuals, in the more detailed biodiversity evaluations (Camelina microcarpa, Polygonum sp., Melilotus officinalis, Centaurea maculosa and Bromus inermis). The number of occurrences and the proportional occurrence of NIS observed in the 37 transects are shown in the table below. NIS proportional occurrences ranged from less than 0.1 percent to 82 percent showing a broad range of representation in the community within the Development Zone. No RPS were found within these transects.

 

 Number of NIS occurrences by species recorded within the Development Zone along 37 transects in 2009.

Species richness of natives and exotics within the Development Zone
Within the Development Zone 151 plant species were scored as present along the biodiversity transects. An asymptotic species accumulation curve (figure below, graph 1A) suggests most vascular plant species in this area were sampled. Also within the Development Area 21 exotic species were sampled and these were evenly distributed along the relative species abundance profile (figure below, graph 1B, solid large circles).

Plans for Continuation
Approximately 60-80 transects are planned for June and July of 2010. A subset of transects conducted in 2009 will be resampled to determine Markov transition probabilities to help ascertain spatiotemporal population dynamics. The biodiversity study will continue within as well as outside the Development Zone. These transect data will be collated to generate probability of occurrence maps and develop preliminary metapopulation dynamics models for the most frequent NIS. The metapopulation models will be finalized after the 3rd year of sampling, again for a small number of NIS.
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