The Connection Between Soil and Deer
Soil has always been fascinating to me. I suppose it's not so much the soil its self but more about how soil is formed, what it contains and how it shapes environments. Soil is a medium that harbours life. It is fundamental in the growth of plants, it holds minerals and billions of miles of mycorrhizal fungi. Soil determines flora types, it is a haven for microfauna, and it teaches us the history of the landscape via deposits of pollen. Soil is the foundation upon which the majority of our natural world stands. From the vast boreal forests of the Taiga to the rainforests of the Congo and to our hunting grounds big and small, soil is ever present beneath our feet.
My fascination with soil brings me to write this blog post and hopefully gives us, the hunters and conservationists a brief but detailed insight into the connection between soil and deer. I am looking at this from a UK perspective but the information can be applied to any area globally that supports deer. This is also coming from a perspective of practical scientific research that I have been involved in.
The differences in the soil types found across areas where deer inhabit have varying biotic and abiotic factors that can affect or influence greatly upon them. It is important to understand such factors when considering any form of wildlife management. These factors may include; hunting logistics, such as the density and height of vegetation in a hunting area, food abundance, deer nutrition, milk production, antler growth, body fat, weight, and disease spread. For the purpose of this post, I thought that I would categorise these effects by discussing them in three very different scenarios; wild deer, park deer and farmed deer.
Wild deer are not only present in varying types of natural habitats they are great at adapting to areas of forest outside their natural range and due to food abundance they are found in high numbers in agricultural areas. The density of deer numbers present in these areas can be determined by two main factors: available habitat (where deer can feed breed and reproduce) and availability of herbaceous food. As a hunter, understanding these areas is key to success. It is important to have an idea of what types of vegetation grow in specific areas and when those types of vegetation are coming into leaf, fruiting or providing a large mast of seed. Due to soil type, certain areas of woodland may have more favourable vegetation. For instance, when considering hunting selective browsers such as roe, success can be down to knowing where a specific or particular species of flora is present.
If the areas in which you hunt or manage deer are located on or around farmland it is important to understand the types of crop planted in the fields and how deer interact with these areas. Soil improvement is a large part of agricultural practice and understanding a farmers year is important to hunting logistics. This makes me think back to a small woodland I used to hunt that was located next to a large farm. I had hunted this area for a number of years and had much success. The fields next to the woodland had been seeded with grass ever since I had hunted there. I understood where the deer would cross the fields and where they would come into the wood. Knowing this was an important part of my success. Little to my knowledge the field was to be ploughed and planted with maize. This was to take advantage of the higher concentrations of nitrates in the soil from the previous years of growing grass. The consecutive years that followed really had an effect on the deer's movements. Visibility through the maize was poor and the deer started to cross the fields using the edge boundary avoiding the woodland altogether. For the next two years, I didn't shoot a single deer in that woodland.
My home farm - Fallow deer crossing maize stubble from woodland to woodland.
For many wildlife biologists, ecologists and deer managers, planning logistics, such as determining deer location, population, and effective areas to focus a cull depend upon the understanding of specific habitats and how to survey them. Almost a decade ago when completing my degree I was undertaking volunteer field research with Scottish Natural Heritage at the Taynish Nature Reserve. The reserve has SSSI (Site of Special Scientific Interest) designation and has an abundance of roe, red, sika and sika hybrid. At the reserve, ecologists take part in annual assessments of natural regeneration levels to assess damage to flora from deer predation with the outcome of determining cull estimates. The assessment covers 17 National Vegetation Classifications. Results from the assessments I took part in concluded that roe deer density/ browsing was highest in W11/ W17 oak woods and lowest in U20 unimproved grassland. This differed somewhat to sika with population density/ browsing highest in heath H10 and lowest in U20 and Mire M23/M24. Results from the assessment revealed where the highest rates of predation were occurring, on what soil type and by which species, with a good approximation of numbers. A map and visual assessment could then be devised to help focus the cull to specific areas. I find this information extremely informative and invaluable when managing a sensitive site. It also gives the deer manager an outline of the primary areas to focus a cull.
A white fallow doe watches intently through the hornbeam and chestnut of an ancient Sussex woodland.
Park deer are of great historical importance and are considered to have a high amenity value. The management of a park herd relies heavily on the natural fodder with a diverse nutritional value. A varied naturalized diet helps to maintain well-proportioned body fat and promotes healthy antler growth. A good example of healthy park deer can be observed at Richmond Park, which contains 700 hectares of lowland acid grassland. The park's status is SSI and supports a highly biodiverse habitat. The grassland habitat benefits from deer grazing, suppressing bracken, pioneer tree species, and increasing light, allowing for the growth of grassland plant species. The faeces and urine of deer help to improve the ecology of the Park. Deer recycle nutrients throughout the grassland; improving the soil that intern provides them with a healthy food source. The composition of deer faeces also supports specialised invertebrate communities, including the rare (Aphodius zenkeri) beetle. This composition can only be formed from the fodder available on an acid grassland habitat.
A magnificent fallow buck grazing on semi-improved acid grassland at Knole Park, Kent.
I would finally like to discuss the connection between soil and farmed deer. Deer farming is a debatable topic within the hunting and conservation community. The progressively intensive production of cervids and the coinciding practices associated with this type of farming (castration, velvetting, feeding of specific diets, etc.) may have a negative impact in the near future on the consumer’s perception of an animal that is primarily wild. In hindsight, this may also have an increase in bias perceptions of a non-hunters view on hunting.
Farmed deer rely on semi-improved or improved fodder crops to help maintain body fat and weight to add value to a carcass. Nutritional fodder also promotes milk production in doe’s to support their young. Healthy populations of farmed deer will have a reduction in the spread of disease, although the statistics of tuberculosis contraction in farmed deer may increase compared to that of deer in the wild. This also begs to challenge the question that, is it possible that a poorly managed deer farm could have implications regarding disease spread to wild deer?
Farmed deer may be susceptible to lead poisoning if they ingest pasture soil with a high content of lead. This may arise if a pasture is located on a historic mining site, an eroded site by a watercourse, a reclamation site where previous waste may have been burnt or tipped, from agricultural runoff, lead shot from a shoot or abandoned lead acid batteries from old electric fencing. Lead contamination can be avoided by testing soil prior to grazing, avoiding some areas altogether, implementing good pasture management, avoiding overgrazing and providing uncontaminated mains water. I feel that this information is equally important to hunters and conservationists that are involved in improving a ranch or farmland for the purpose of outfitting or wishing to increase the diversity of wildlife on a specific site.
I would like to close this post with some final thoughts. Whether you are a deer manager, a park ranger, wildlife biologist or hunter of wild deer, understanding the soil beneath our feet and how it determines the habits in which we passionately strive to conserve is one of the many important factors that contribute to our unified goals.