Changing elevation in the Southwest changes temperature, precipitation levels, evaporation rates and results in dependable and predictable changes in both flora and fauna. I consider these to be ‘normal’ places provide ‘normal’ flora. Keep in mind that even an undisturbed environment with average temperatures, water supply and sunlight for a given climate will provide many plants useful to humans.
The tips in this article are for going beyond the norm by looking for those often overlooked micro-climates and micro-environments.
Human Altered Environments
~By old homesteads – look for apple and other fruit trees, asparagus, peppermint and catnip
~Pre-historic sites may have extra diversity due to either food cultivation by the inhabitants or disturbed soil
~Tanks in the forest or on grazing land provide both disturbed soil and additional water.
~Over-grazed land is especially good for prickly pear and mesquite
~Disturbed soil is best for edible greens that are often considered weedy – this includes areas along trails, roads, parking areas, sidewalk cracks, fallen trees, recent burns and old homesteads
~Recent burns are good for mullein – either forest fires or the brush piles. Elder bushes often move in within a few years as a stage of forest recovery.
~Along fences – on a micro level, these areas may receive more shade from the fence and not be as heavily grazed
Environments with Extra Water
~Near any water source, even if it is just a trickle
~Sandstone cliffs where water seeps out forming hanging gardens – lots of other plant possibilities near the hanging gardens
~Riparian habitats are shadier and cooler than their immediate surroundings, have higher localized humidity and a higher water table – this breaks all the textbook rules about what you might find, especially in an arid environment. The flora in these areas is not dependent on rainfall, using the higher water table instead.
~In a drainage, even one that is dry most of the year – it need not be a canyon or named stream bed, it might be just a minor depression in the landscape
Environments Where the Physical Topography Makes the Immediate Areas Noticeably Cooler, Hotter, Wetter or Drier than the Norm
~Along the south facing, rocky rim of a cliff – this is a good place to find yucca and prickly pear, even at 7,000’. Many places along the Mogollon Rim fit in this category.
~Rocky, southern slopes in general will be warmer and drier than usual – the south slope of Mt Elden has plants usually found at lower elevations
~Rocky areas can support lower elevation plants because (1) they absorb and radiate heat or (2) they can be drier because the water runs off or (3) they can hold pockets of water and create a wetter micro-climate. Lots of possibilities here.
~Adjacent to individual large rocks and boulders – these areas often receive extra water due to the rock runoff and extra heat due to radiative heat loss at night
~Nurse trees – juniper, mesquite and palo verde often provide cool, moist shade on their north side, allowing young plants of other species to grow. This is especially true below 5,000’ in Arizona but i have seen it under Ponderosas at 7,000′ also.
~On the north facing slope which is more shaded and cooler than normal. I have encountered Douglas Fir in the red rocks of Sedona in such a locale.
Sky Island Mountains
By definition, sky islands are solitary mountains or small ranges that are surrounded by desert. The flora and fauna are limited in their range. Seeds from other 10,000’+ mountain ranges are much less likely to travel to the San Francisco Peaks because of the vast expanse of low elevation desert that must be crossed.
The primary limiting factor to plant diversity on these solitary desert peaks is that they have a limited range for seed dispersal. In mountain ranges that cover extended areas, such as the Sierra Nevada or the Rockies, seeds may be dispersed by animals or wind over many hundreds or thousands of square miles. This aids in both extending the range of a plant or re-seeding an existing population.
Smaller ranges also have few or no streams and are lacking in the potentially diverse riparian habitats.