varEst                package:popbio                R Documentation

_E_s_t_i_m_a_t_e _t_h_e _v_a_r_i_a_n_c_e _o_f _b_e_t_a-_b_i_n_o_m_i_a_l _v_i_t_a_l _r_a_t_e_s _u_s_i_n_g
_a_p_p_r_o_x_i_m_a_t_i_o_n _m_e_t_h_o_d _o_f _A_k_c_a_k_a_y_a

_D_e_s_c_r_i_p_t_i_o_n:

     This function finds the best estimates of mean and environmental
     variance for beta-binomial vital rates, using the approximation
     method of Akcakaya (2002).

_U_s_a_g_e:

     varEst(rates, weighted=1)

_A_r_g_u_m_e_n_t_s:

   rates: a matrix or dataframe with four columns: Rate identifier,
          Year, Total number of starting individuals, Number surviving
          (or growing)

weighted: either 1 for weighted average demographic variance, or 0 for
          unweighted average, default is 1.

_V_a_l_u_e:

     A matrix with 3 columns: (1) total observed variance, (2) estimate
     of variance due to demographic stochasticity, and (3) estimate of
     variance due to environmental stochasticity.

_A_u_t_h_o_r(_s):

     Patrick Nantel, 20 June 2005. Last modified May 1st 2007.

_R_e_f_e_r_e_n_c_e_s:

     Akcakaya, H. R. 2002. Estimating the variance of survival rates
     and fecundities. Animal Conservation 5: 333-336.

     Kendall, B. E. 1998. Estimating the magnitude of environmental
     stochasticity in survivorship data. Ecological Applications 8(1):
     184-193.

_S_e_e _A_l_s_o:

     'Kendall'

_E_x_a_m_p_l_e_s:

     data(woodpecker) 
     varEst(woodpecker)

