Anthropogenic Threats to Bee Populations in New Mexico

Background and Motivation

Bee populations have been in the decline for decades, now down more than 60% since 1947 (Greenpeace, n.d.). With the loss of bees comes the loss of invaluable pollination services to about 80% of flowers, crops, and other plants worldwide. If the bee were to go extinct, life as we know it would cease to exist. Pollination services would mostly fall to humans, who would not be able to complete the task as efficiently (or as inexpensively) as their insect counterparts, and food shortages would become the new norm. Unfortunately, these serviceable creatures face many threats, including parasites, diseases, and other predators. The top killers of bees, however, are legacies of man: habitat fragmentation, monoculture farming, and pesticides.

Objective

The purpose of this project was to gather and interpret data about the history and present status of habitat fragmentation, monoculture farming, and pesticide use in New Mexico to predict future statuses of these three aspects. Using the future projections, I will then assess the severity of threats to bee health in the state.

Fig. 1. The focus area, New Mexico, USA.

Methods

All shapefile data was found on ArcGIS Online. Content data was found from various sources. Because all of the maps I made were of New Mexico, I chose the projection of NAD_1983_2011_Contiguous_USA_Albers. Changing the central meridian to 106W helps the state of focus to not appear “short and squatty”. All maps were made on ArcMap 10.7.1.

Results

The map depicting magnitude of habitat fragmentation showed that in the southern and eastern areas of the state, fragmentation was relatively low. This certainly makes sense for the southern region, as it is mostly desert and development in this area has been slow. The eastern biome isalso Chihuahuan desert mixed with Western short grasslands. While these two areas are relatively low-risk, the majority of the state is in the medium-high range of fragmentation magnitude. This includes biomes of Arizona mountainous forest, Colorado plateau shrublands, and Colorado Rockies forests. The high magnitude of fragmentation for these habitats means that the natural spaces that the bees must travel to become fewer and far in-between, increasing difficulty of finding viable food sources and mates, and decreasing genetic diversity and, in turn, resistance to disease and parasitism (Naug, 2009).

Fig. 2. Biomes of New Mexico, USA.

Fig. 3. Magnitude of Habitat Fragmentation in New Mexico, USA.

The map of crop patterns in New Mexico indeed shows a problem of monoculture farming. The vast majority of the state appears to be monopolized by only six types of crops, with the top three (alfalfa, corn, and pecans) accounting for the better part of that majority. Lack of diversity is problematic because it results in a uniformed flowering time for the crops, meaning there will be an abundance of food for the bees for a short period of time, and then an extreme food shortage over a large area after this period (Donaldson-Matasci, 2013).

Fig. 4. Major Crops by Area in New Mexico, USA.

The pesticide use data showed an interesting progression from 1992-2009. Pesticide use in almost every county increased by 1997. By 2009, some counties had somewhat curbed their pesticide use, though overall, New Mexico was spraying more pesticides in the most recent year than in the earliest. This is detrimental to bee populations, as pesticides are not only toxic to bees themselves, but they decimate potential food sources for the bees.

Fig. 5. Pesticide Use from 1992-2009 in New Mexico, USA.

Conclusion

Habitat fragmentation, monoculture farming, and pesticide use are three major threats to bee populations. Unfortunately, all three of these are occurring in New Mexico, and unless there is a major shift in agricultural practices, bee populations will continue to be decimated, potentially irreversibly so. According to a study by MIT, if bee populations drop to a level where crops need to be hand pollinated by humans, it could cost upward of $2.6 trillion annually to do the work that bees do for free (2015). A future without bees is unimaginable, so an agricultural reform needs to happen soon.

Future Work

If this study were to be replicated, I would encourage a deeper look into the data for pesticide use and habitat fragmentation. The data included in the shapefile used specific numbers, but without units or other numbers to compare it to, it’s somewhat irrelevant. In addition, a more in-depth look at crops in New Mexico would be helpful. Because the data for major crops was by acreage, it left out certain crops, giving the maps a less-than-full scope. I would also like to get data on actual bee populations in the state in order to compare them to the results and predictions of this project.

References

(2015). In Mission 2015: Biodiversity. Retrieved May 8, 2020, from https://web.mit.edu/12.000/www/m2015/2015/bee_tech.html

ArcGIS Online. (2017). Pesticide Use by author jsc2245_columbia. Retrieved through ArcMap on 05/04/2020.

Donaldson-Matasci, M. (2013, June 7). In Honeybees and monoculture: nothing to dance about. Retrieved May 8, 2020, from https://blogs.scientificamerican.com/guest-blog/honey-bees-and-monoculture-nothing-to-dance-about/

Greenpeace. (n.d.). In Save the Bees. Retrieved May 5, 2020, from https://www.greenpeace.org/usa/sustainable-agriculture/save-the-bees/

Hoekstra, J. M., J. L. Molnar, M. Jennings, C. Revenga, M. D. Spalding, T. M. Boucher, J. C. Robertson, T. J. Heibel, with K. Ellison. 2010. The Atlas of Global Conservation: Changes, Challenges, and Opportunities to Make a Difference. Ed. J. L. Molnar. Berkeley: University of California Press.

Naug, D. 2009. Nutritional stress due to habitat loss may explain recent honeybee colony collapses. Biological Conservation 142: 2369-2372.

Appendices

Beginning with habitat fragmentation, I first made a reference map of New Mexico and the different biomes within it. I overlaid a map of the United States over the habitat fragmentation layer, then used a definition query to exclude every state other than New Mexico. I then used the selection features to get rid of all biomes other than ones inside of the state. I changed the symbology so that the biomes reflected something close to how I feel they would appear in real life. As I did in all the maps (other than Fig. 1.), I added the Rio Grande for reference. I then included a legend and a title.

Next, I did many of the same things as above to create the fragmentation magnitude map. Once I had only the habitats inside of New Mexico, I changed the symbology to get darker with increased risk of fragmentation. For this legend, I used a scale of “low” to “high” instead of exact numbers because without something to compare these numbers to, they didn’t make much sense.

For the monoculture farming map, I first uploaded the Pesticide_Use shapefile, which also contains data about crops. I again used a query builder to exclude all U.S. states other than New Mexico, then used the select by features/location tools only include crops in the state. This came out cleaner than the previous maps because the data is by state rather than by region. I again changed the symbology to reflect the different types of crops, making the top 3 patterned to stand out, and leaving the rest as solid colors. I also rearranged the order of the crops so that the top 3 by area would be first in the list on the legend. I lastly added a scale bar and titles.

Lastly, for the pesticide map, I began again by uploaded the Pesticide_Use data from ArcGIS Online. After using the query builder and selector tools to isolate New Mexico and its pesticide use by county. Pesticide use data in this set goes from 1992-2009, so I made four different maps, identical except for changes in pesticide use, which was shown by changing the symbology to go from green to red, with red indicating a higher use. Again, in this legend, I used references of “low” and “high” to avoid confusion with using the actual data with no frame of reference to compare them to. I put the four maps together in order of progressing dates, added the same base map to them all, then put the legend in the middle and added a title.