Recovering Caches Of Squirrels (sciurus Vulgaris) And Its Effect On Natural Regeneration Of Korean Pine (Pinus Koraiensis) In Liangshui Natural Reserve

Squirrels(sciurus vulgaris) and Korean pines(Pinus koraiensis)both are the important species with highly economic values in the forest area in Northeast of China. Squirrels' evolutional hoarding behavior and the dependence of dispersal of Korean pines' seed on hoarding animals make them become a perfect materials for the studies that about relationship between hoarding animals and plant's dispersal. In this paper, form November of 2004 to April of 2005 in LiangShui National Nature Reserve, the intensities of squirrels' recovery in the different periods of this winter, chracteristics of recovery caches and relationship between recovery caches and seedlings of Korean pine were studied by means of field sampling survey covering with snow ; in addition, the squirrels' function of maintaining the stability of Korean pine forest bio-system was explored at the scale of landscape through GIS modeling. The results showed as follows:1) The amount of caches ate by squirrels immediately after recovery among measured recovery caches in LiangShui reaches to 83%, in which the caches with 1 and 2 seeds are 163 and 59, and reached to 68.2% and 24.7% respectively; the caches beyond 3 seeds are few. The maximum diameter of recovery caches is 28.3cm and the minimum one is 12.7cm, the average is 19.2cm. The maximum depth of recovery caches is 14.3cm and the minimum one is 4.5cm, the average is 9.8cm. The maximum thick of snow-cover is 9.1cm and the minimum one is 1.1cm, the average is 4.5cm. Among the measured foot chains of recovery, the maximum distance reaches to 18.1m and the minimum one is 6.5m.2) The intensity of squirrels' recovery in beginning winter is higher than ones in middle winter and in later winter, and which one in later winter is lowest among them. There are a significant difference between them ( x² =17.247 , df=2, p<0.05). This pattern of recovery allocation in different periods of winter complies with the squirrels' foraging economical law that minimizing the famine risk.3) The multi-variable regression equations of recovery caches and seedlings respectively to environmental factors isy=0.0844X₁₂-0.2745X₁₃+0.1791X₁₄-0.0988X₁₅-0.0944X₁₆-0.1818X₁₇-0.2881X₁₈-0.4495X₁₉+0.4498X₂₁+0.1939X₃₁-0.2040X₃₂+0.2104X₃₃+0.0005X₃₄-0.0090X₃₅-0.1929X₃₇-0.1834X₃₈-0.1578X₄₂-0.4449X₄₃+0.0369X₅₁-0.3351X₆₁-0.2284X₆₃-0.1083X₆₄-0.3787X₆₅-0.0810X₇₁+0.0683X₇₂-0.1738X₇₃+0.1991X₇₅+0.0491X₈₁-0.2811X₈₂-0.0545X₈₃+0.2659X₉₁+0.0226X₉₂+0.0316X₁₀₁+0.1552X₁₁₁+0.4544X₁₁₂+0.1542X₁₂₁+0.2779X₁₂₂ (F=2.605, P=0.003(df=37, 268) , R=0.860, R2=0.739)y=0.084X₁₂-0.278X₁₃-0.169X₁₄+0.060X₁₅+0.170X₁₆+0.102X₁₇+0.070X₁₈-0.018X₁₉-0.406X₂₁-0.188X₃₁-0.352X₃₂-0.051X₃₃+0.073X₃₄-0.269X₃₅-0.261X₃₇+0.006X₃₈-0.254X₄₂-0.324X₄₃+0.376X₅₁-0.335X₆₁-0.043X₆₃-0.284X₆₄-0.074X₆₅-0.288X₇₁-0.174X₇₂-0.217X₇₃-0.335X₇₅+0.271X₈₁+0.031X₈₂+0.142X₈₃+0.230X₉₁-0.061X₉₂-0.004X₁₀₁+0.001X₁₁₁-0.324X₁₁₂+0.086X₁₂₁+0.173X₁₂₂(F=0.985, P=0.520(df=37, 268) , R=0.719, R²=0.517)4) There is a negative effect at the amount distributions between recovery caches and Korean pine seedlings in LiangShui. (r =-0.2453, p = 0.0471; y = 55.2136462-0.152516209x).5) By GIS modeling, it showed that the recovery caches have a highest density in the areas of compartment #1, #2, #4, #9, #10, #12, #13, #19, #20, #22, #23, #25, #26 and #29 in LiangShui; and the seedlings do in compartment #2, #3, #5, #6, #8, #9, #10, #14, #15, #16, #18, #22, #23 and #25. The zones that showed obviously negative relationship between caches and seedlings locate in some areas of compartment #3, #5, #6, #7, #10, #14, #16, #18 and #25, which reaches to 35% of total area of LiangShui. These distribution relationships at the scale of landscape indicated that squirrels are the main contributor to the Korean pine forest's natural regeneration.6) surveying the recovery caches in field with snow-cover and exploring the relationship between squirrels and Korean pine forest's regeneration at the scale of landscape are feasible in LiangShui.