All the plants ,animals,microorganisms,the genetic variations within each species and the ecosystems where each is found and functions is called biodiversity. A compound of the words biological + diversity, defined not just as a giant list but also a data base of community and function that acts together to create the world around us.
How much can be lost before function falters?
Do our gardens make a difference?
Honestly, I don't know but I'm growing some native plants, reading what I can and hanging out with people that are trying to make a difference.
Here is a bit of what is available online.Genetic diversity helps organisms cope with current environmental variability.
Organisms exist in environments that vary in time and over space. Such variation is often described in terms of the natural or historic range of variability (NRV, HRV) in environmental conditions such as weather, disturbance events, resource availability, population sizes of competitors, etc. (White and Walker 1997
A diverse array of genotypes appears to be especially important in disease resistance (Schoen and Brown 1993; McArdle 1996). Genetically uniform populations (such as highly inbred crops) are famously vulnerable to diseases and pathogens, which can (and do) decimate populations in which all individuals are equally vulnerable. Such uniformity also predisposes a population to transmit disease from one individual to another: instead of having isolated diseased individuals, nearly every individual may be exposed to disease by direct contact or proximity. More diverse populations are more likely to include individuals resistant to specific diseases; moreover, infected individuals occur at lower density, and thus diseases or pathogens may move more slowly through the population.
NPS gov pubs restoration genetics 1There are genetic differences among individuals within most (but not all) populations of plants and animals. There are also differences among populations across the range of each species. In this section we review some basic patterns of how genetic diversity of species is distributed, or partitioned
Each species distributes its genetic diversity (one measure of which is the total of all alleles at all loci) in a pattern reflecting both its biology and its history (Wright 1965; Nei 1975). For example, nearby populations of plants that are pollinated by bees may share many alleles because genes (packaged in pollen grains) can flow easily between sites. Such species may have fewer unique alleles in each population, so populations tend to be genetically similar. By contrast, there may be less gene flow among populations of species that are pollinated by ground-dwelling flightless beetles, or whose heavy fruits fall to the ground in the vicinity of the parent tree. Gene flow can also be obstructed by physical barriers (i.e., topography or habitat that a pollinator, disperser, or migrating individual cannot cross), as well as by disturbance (Levin 1981; Slatkin 1987).
NPS gov pubs 2Yale Lecture Video By Stephen C StearnsUPRM edu biologyStanford edu biodiversityBiodiversity, what it is and why it is important is explored in this
'Stanford Encyclopedia of Philosophy' definition.
I liked the concept of biological diversity being seen not just as a list of living organisims but
but also including ecosystem processes that maintain,support and repair damage .
A holistic view that tries to understand how each part works with other parts to create and continue ecosystem services to the whole.