While Rocky Mountain elk have thrived across many parts of the West, Lolo zone elk in Idaho have been declining for 20 years. This area is just over the mountain from Montana’s Bitterroot Valley, and Thompson Falls MT where many wildlife populations have been in decline for the last 20 years. The Lolo and Selway areas hold some of the highest concentrations of Idaho’s clear cuts. Herbicide use in timber harvest has been increasing for decades. Elk in timber harvest areas, like the Bitterroot Valley, WA and OR have been suffering declines and malformations, while most elk have thrived in areas devoid of these practices.
Studies have shown that these declining elk have lower selenium levels, and pregnancy rates, compared to other areas(3). It has been shown that cow elk in these declining herds have low progesterone levels. It has been proposed that these low progesterone levels are a result of Predators. “The predation stress hypothesis suggests that exposure to predators causes elevation of glucocorticoid (GC) stress hormones (10, 16–18), which can directly suppress reproduction through effects on the hypothalamic-pituitary-gonadal axis (19, 20), and can indirectly reduce survival and reproduction through effects on the immune and digestive systems”
While the predator hypothesis has not panned out, it has been shown that endocrine disrupting herbicides can achieve exactly what has been proposed to be caused by predators. 60% of all pesticides are endocrine disruptors, that affect the hypothalamic-pituitary-gonadal axis. Elevated glucocorticoid levels are associated with insulin resistance and diabetes(1) in the same way that we see copper and selenium deficiencies associated with metabolic disorders and diabetes.
“Glucocorticoids bind to the cytosolic glucocorticoid receptor (GR), a type of nuclear receptor that is activated by ligand binding. After a hormone binds to the corresponding receptor, the newly formed complex translocates itself into the cell nucleus, where it binds to glucocorticoid response elements (GRE) in the promoter region of the target genes resulting in the regulation of gene expression. This process is commonly referred to as transcriptional activation, or transactivation.” “The proteins encoded by these up-regulated genes have a wide range of effects, including, for example: secretory leukoprotease inhibitor 1 (SLPI)” There is correlative relationship between SPLI and the pappiloma virus. The pappiloma virus has been seen in fibromas that appear in association with malformed and declining deer. Those fibromas are also correlated to metabolic disorders and diabetes.
Progesterone and estrogen balance each other in the body. When estrogen is increased progesterone is decreased. This can also happen when estrogen mimics like many pesticides trick the body into thinking that estrogen levels have risen, this in turn causes progesterone to decline. Glyphosate which is used in forestry practices in the Lolo has been shown to suppress progesterone expression(5)
As is seen with pesticides and SHh disruption in other related wildlife declines and associated malformations, we see a role for disrupted SHh and related zinc finger proteins(Gli) with regard to suppressed progesterone numbers seen in Lolo zone elk.
Figure 3: Correlation among Shh signaling molecules and estrogen and progesterone receptors (ER/PR). (a) Normal endometrium; (b) endometrial hyperplasia; (c) endometrial carcinoma. g, glandular tissue; Gli-1(c), Gli-1 cytoplasmic expression; Gli-1(n), Gli-1 nuclear expression; Gli-2(n), Gli-2 nuclear expression; Gli-3(c), Gli-3 cytoplasmic expression; PTCH, Patched; s, stromal tissue; SMO, Smoothened. Negative correlation: () P < 0.01; () P < 0.05; positive correlation: () P < 0.01; () P < 0.05.(4)
Elevated glucocorticoid levels, could also be the result of sulfonylurea induced hypoglycemia. Sulfonylureas induce hypoglycemia by acting on the pancreas, when hypoglycemia is induced, cortisol(glucocorticoid hormone) is released, in an attempt to reverse the hypoglycemic state. Solfonylureas are ALS inhibitors as is the herbicide glyphosate.
Much of the timber harvest in the Lolo zone is conducted on Potlatch property. Potltatch corp uses herbicides in its timber harvests, like most timber companies over the last 30 years.
Besides timber harvest there is the issue of weed control. ” When the U.S. Forest Service (USFS) stopped spraying herbicides in the Lolo National Forest during the 1980’s, it did not adequately address the potential spread of invasive weeds with an alternative approach. During this time, invasive weeds took hold and began to spread through the Lolo Forest. Reacting after years of a “do nothing” approach, USFS reintroduced herbicides into the Lolo National Forest for the ﬁrst time in 1992, as part of its weed management program. “