YearMari RobertsBSC3052 Sec 3October 5, 2012Orchid PVA Computer LabBriefly describe how you might collect the data you need to build your model- decide how many stages to include (seeds, seedlings, vegetative, dormant, flowering)- understand the species- calculate transitions (14 total)- fraction surviving but not growing (dormant)- fraction surviving and growing- number of seeds/fruit/year- make a population (projection) matrixF5=[(1.2)(21618)](0.53)=13,749.048S1=0.40G35=0.141Year Plants Flowering Probability1990-1991 74 0 01991-1992 54 10 0.1851992-1993 154 53 0.3441993-1994 361 12 0.033Average 160.75 18.75 0.141=G35[0.40 0.0 0.0 0.0 13749 ][10][0.0015 0.0 0.0 0.0 0.0 ][10][0.0 0.0301 0.2806 0.0815 0.2106][10][0.0 0.0 0.5783 0.1015 0.5968][10][0.0 0.0099 0.141 0.0299 0.2025][10]Mari RobertsBSC3052 Sec 3October 5, 2012Determine Current Status:Is the population growing or shrinking in the first generation? shrinkingTo support your conclusion, provide the lambda for the first year (current lambda). 0.79Is the population at its stable stage distribution in the first generation? How can you tell? Choose and provide an appropriate graph to support your answer. Yes. The stage structure (proportion of t in stage x) of population changes over time stabilizes at the first generation (figure below).Figure: Nx/ENx vs. t for stage 1Can you always infer the long-term behavior of a population based on a few years of calculating lambda as Nt+1/Nt? Why or why not? No, this will only be constant if the population is ata stable stage distribution. Lambda is constant as long as P stays the same. The count based model treats all individuals the same. The stage-based model in-cludes life stages, which are useful to infer long-term behavior of a population (Nt = PNt−1).Determine Future Status:What will this population do in the long-term future? To support your conclusion, provide the long-term average lambda. lambda = 0.963 The population will decline in the long-term future (by 3.7%)Choose a quasi-extinction threshold (minimum population size you will tolerate). If the population will go quasi-extinct, roughly how long will that take? Provide a graph of total number in the population over time (long enough to show extinction if it is expected) to support your conclusion. Hint: you can overlay a grid on your graphs using the “options” menu at the top of the graph page. About 250 generations for the population to reach zero.Mari RobertsBSC3052 Sec 3October 5, 2012Determine which life-stages should be targeted for management Calculate and report the survival elasticity for each life stage. For each stage in turn, change all ele-ments except fecundity by 5% each and calculate the elasticity. Seeds: 0.134Seedlings: 0.0834Vegetative: 0.0415Dormant: 0.00374Flowering: 0.0623Also calculate and report the elasticity for fecundity. 0.187Which stage(s) should be the focus of management? Seed viability should be the focus of management. Increasing the amount of vi-able seeds by 5%, increased the value of lambda to 0.97. This also had the high-est elasticity value (0.134). Fecundity elasticity = 0.187.Management options There is pressure from local citizens to make use of the areas where the WPFO grows. For example, 1. Use the field as a hay field, which means mowing each year. This results in cutting leaves off of plants, which de-creases flowering and vegetative plant survival. 2. Allow spraying of nearby crops with insecticides to reduce agricultural pests, knowing that these sprays will re-duce the number of pollinating moths (moths are killed by the insecticide). 3. Drain the field, which will dry out the soil and reduce seed viability and the chances of seed germination. Option 2 would be the least harmful to the WPFO. Option 3 would be the most harmful. Seed viability, or seed germination, is the most important stage of or-chid population viability because it has the greatest effect on lambda and the largest elasticity value. When I decreased the seed viability by 50%, the lambda changed to 0.849. I repeated these calculations for the vegetative stage and flowering stage. The negative effect on seed viability had the most drastic effecton lambda and would decrease the population of orchids significantly. How might you deal with conflicts that could arise with citizens whose activities might have to be curtailed (e.g. if you chose to allow spraying but not haying)? - Prolong mowing of the fields until after the seeds have become embryos and reached adulthood. This would increase seed and embryo viability.- reduce the amount of draining, as the loss of water has the biggest impact on WPFO populations. - Citizens could use the field for cattle, if grazing was at a managed time. Cattlehave been known to disperse seeds over a given area and could help plant seeds into the soil. This could increase seed viability.Mari RobertsBSC3052 Sec 3October 5, 2012What are some possible weaknesses of the model you used for this PVA, and how might they affect your conclusions? The PVA could be more accurate if it was run for more than 5 years. Running a PVA model for a longer time period would yield a better long-term average lambda. This model also did not take into account the presence of demographicstochasticity, genetic variation, or environmental effects (such as Options 1,2,3).Taking these aspects into account would have made our long-term average lambda more accurate as well.What additional data or analyses might allow you to make a better recommendation for management of this species? - take into account the presence of demographic stochasticity, genetic varia-tion, and environmental effects (such as Options 1,2,3) The PVA performed excluded the details of habitat change or the involvement of any manage-ment or conservation of the