The beautiful Sonoran desert

I love the varied topography and vegetation of the Tucson area, and especially up in the foothills of the Catalina mountains on the road to Oracle (what a great name). Here are some views of the mountain landscape from Catalina State Park at sunset today.

Catalina Mountains, Tucson, AZ

Catalina Mountains, Tucson, AZ

Catalina Mountains, Tucson, AZ

Catalina Mountains, Tucson, AZ

the creek

I am intrigued by the idea of a creek that runs through the heart of a dense urban area with mostly clear water and that supports a variety of wildlife along its riparian border.

Los Gatos creek, Campbell Park, San Jose, CA

Water levels may fluctuate, but there is always enough to support wildlife.

Los Gatos creek runs northward 24 miles from the Santa Cruz mountains through the once orchard-rich, now highly residential Santa Clara valley to join the Guadelupe River which eventually empties into the southern end of San Francisco Bay.

Los Gatos creek, Campbell Park, San Jose, CA

Steep slopes along its course have been lined with sandbags or rocks to prevent the inevitable erosion of soft soils into the river that would dam its flow.

Along its length, the creek feeds two reservoirs and several small impoundments meant to recharge the ground water and prevent San Jose from subsiding as water is drawn from underground storage during urban development.

Los Gatos creek, Campbell Park, San Jose, CA

Creek water is aerated as it cascades over waterfalls and dams along its course.

Los Gatos creek, Campbell Park, San Jose, CA

In places, the creek becomes a narrow channel, where water moves swiftly over rocks.

Hard to believe you’re in the middle of a major metropolis when you stand by the creek and watch a Coopers Hawk take down an errant little bird on the opposite shore.

Los Gatos creek, Campbell Park, San Jose, CA

Maples, oaks, sycamores, and cottonwoods line the shore of the creek, creating colorful landscapes and providing cover for wildlife.

Walking north on the trail along the creek toward downtown San Jose, I came across an unusual painting on one of the many highway overpasses.

Los Gatos creek, Campbell Park, San Jose, CA

Was this creek a salmon run?

In the late 1800s, “speckled trout” (probably the steelhead, or pacific rainbow trout) were apparently so numerous in the creek, they could be caught by hand.  But agricultural development in the valley lowered the water table too much to sustain the salmon migration, until the reservoir and percolation pond system raised it.

Today tagged steelhead trout and Chinook salmon once again migrate up the Guadelupe River and Los Gatos creek from San Francisco Bay, which is a testament to the health of this urban riparian system.

Birding in a Florida salt marsh

What a pleasant surprise to find such a rich and interesting wildlife refuge just an hour north of Cape Canaveral — Blackpoint Drive, a 7 mile road along dikes in a salt marsh that is part of the Merritt Island National Wildlife Refuge.

Blackpoint Drive wildlife refuge, Titusville FL

A typical scene along the dike roads of mangroves and pools in the salt marsh.

Here’s how the Fish and Wildlife Service describe this unique area.

Imagine a broad, flat expanse of salt marsh stretching from where your car is parked to the Indian River, a distance of about 1 mile. The only obstruction is an occasional hammock of palms or a mangrove-rimmed pond, and behind you, on higher ground, slash pines. Marsh streams gracefully wind through the marsh and provide a thoroughfare for microscopic plants and animals, shellfish and fish. Egrets and herons are poised along the stream edge, like spearfishermen patiently awaiting a meal. Secretively, sparrows search for insects in the chest-high grass. Occasionally, tides aided by a strong wind flood the marsh, and on the ebb, nutrient-laden waters are exported to the river. The marsh and river are one.

Blackpoint Drive wildlife refuge, Titusville FL

An island of palmetto on higher ground stands behind the sea of grass in the salt marsh.

Although we were visiting before the big influx of winter migrants arrived, there was still plenty to see, which is why a 7 mile drive took us more than 3 hours. Butterflies, lizards, lots of birds, alligators, and even a errant manatee that wasn’t supposed to be in this area of the salt marsh crossed our path.

Tri-colored Heron, Blackpoint Drive wildlife refuge, Titusville FL

Tri-colored Herons were common in the shallow pools lined by mangroves.

Tri-colored Heron, Blackpoint Drive wildlife refuge, Titusville FL

This one was pretty tame, and walked right up to us.

Greater Yellowlegs, Blackpoint Drive wildlife refuge, Titusville FL

Greater Yellowlegs foraged in the shallow mudflats.

Blackpoint Drive wildlife refuge, Titusville FL

A few flocks of small dabbling ducks floated in the deeper pools, but quickly took cover in the mangroves when they spotted us.

Alligator, Blackpoint Drive wildlife refuge, Titusville FL

Floating in some of those same deep pools were alligators of various sizes, from small like this one to very large.

Little Blue Heron, Blackpoint Drive wildlife refuge, Titusville FL

A solitary Little Blue Heron stalked its prey.

Great Blue Heron, Blackpoint Drive wildlife refuge, Titusville FL

Mangroves make useful perching spots for both Great Blue Herons and Great (White) Egrets.

Yellow-dumped Warbler, Blackpoint Drive wildlife refuge, Titusville FL

Yellowthroat and Yellow-rumpled Warblers were frequently seen foraging in the low bushes and mangroves along the water’s edge.

Juvenile and adult Common Moorhens, Blackpoint Drive wildlife refuge, Titusville FL

Common Moorhens must have raised their brood in these pools lined by mangroves. This juvenile bird is flanked by two adults in the background.

Manatee, Blackpoint Drive wildlife refuge, Titusville FL

The manatee was swimming along the edge of a small stream, squeezing itself through culverts that connected waterways. Apparently they are restricted from this area because they get stuck and have to be rescued and removed by wildlife biologists.

Black Vultures, Blackpoint Drive wildlife refuge visitor center

We found Black Vultures resting in the shade on the lawn of the visitor center 2 miles up the road from the wildlife refuge. It was close to 90 degrees and very humid, so no wonder they took refuge here.

What an amazing area, the last remnant of the natural salt marshes that probably lined the eastern coast of Florida before it was extensively developed. Not only is it a haven for wildlife, but it’s a natural barrier to storm surge and salt water intrusion inland.

Beautiful Bar Harbor

Another cloudy day, but Mt. Desert island (pronounced “dessert”) did not disappoint.  The Acadia National Park service shuttles in the park had ceased operation 4 days ago, which made sight-seeing without a car difficult, but we found a 2 hour tour of park highlights that was all I could have wished for.  The fall color was spectacular everywhere, even through cloudy, rainy fog.

a few of the highlights of our tour…

Acadia National Park, Bar Harbor, ME

Acadia National Park, Bar Harbor, ME

Acadia National Park, Bar Harbor, ME

Acadia National Park, Bar Harbor, ME

Acadia National Park, Bar Harbor, ME

View of Bar Harbor harbor area from the top of Cadillac Mt. 45 mph wind up here!

Lobster traps, Bar Harbor, ME

Lobster traps in the bay

Islands off Bar Harbor, ME

The sun came out just as we were leaving the area!

Fall harvest gone wild

This should be called the year of the fantastic nut crop: acorns by the ton, walnuts carpeting the lawn, and buckeyes remaining unharvested because there is a food surplus in the backyard like never before.

Ohio buckeye nuts

The Ohio Buckeye tree is loaded with nuts, which the squirrels should have harvested by now.

Why is this happening?  I don’t remember there being great spring weather; oh wait, I was in the UK during spring.  The summer was the usual blend of hot and humid interspersed with cold and rainy, so it must have been perfect for growing a huge nut crop.  But why have all the oak trees in the backyard gone crazy with acorn production?

Oak acorns

The forest floor has become crunchy with fallen acorns. This is just what the squirrels leave behind.

We are experiencing a “mast year” in oak tree production of acorns, which happens irregularly, every two to five to seven years.  And it’s happening in not just one species of oak, but simultaneously in the three most common Minnesota oak species — the northern pin oak, the northern red oak, and the bur oak.

Bucks eating acorns, photo by Charles Alsheimer

In a normal year of acorn production, animals consume or store most of the acorn crop, leaving little chance that the nuts could sprout into seedling oaks. Photo by Charles Alsheimer.

In a recent post (September 12), I discussed how trees “talk” to each other, and this synchronous boom production of acorns is a good example of the result of that communication, which can occur not only locally within a forest, but over broad distances.  Basically, mast production of acorns is the trees’ combined strategy of satiating the acorn consumers so that the leftovers can develop into seedlings.

The oaks must have been talking to the walnuts in the backyard as well, and the squirrels are just not able to keep up with the bounties of this fall harvest.

Gray squirrel husking a walnut

Bring all your friends, Mr. Squirrel, I’ve already raked up a garbage can full of walnuts.

The perfect response to this enormous fall bounty — “stop, I’m full already”.

National Geographic funny animal photos, 2018, Photo by Mary McGowan, CWPA, Barcroft Images

National Geographic funny animal photos, 2018, Photo by Mary McGowan, CWPA, Barcroft Images.

A short history of apples

This is a rewrite of a post from September 2015, during the first fall harvest of my “apple orchard” (four dwarf trees).

This is apple harvest time in Minnesota, home of the Honeycrisp variety of apples, so loved by everyone who has tried one.

honeycrisp apples-

My honeycrisp apple trees are so loaded with apples, the branches are bending down to the ground.

It seems to be a Fall for bumper crops of all types of apples, from crabapples to honeycrisp, judging from the loaded branches of the apple trees on my street.

apple tree-loaded with fruit

An apple tree loaded with fruit awaits harvest. Squirrels take one bite and spoil a perfect apple, and the deer finish them off when they fall to the ground. 

Originally native to Kazakhstan, this highly productive forest tree has spread around the globe, even though the original progenitor was a small, sour, shriveled fruit that probably was more often used for a fermented beverage than eating.  After all, its genus name is Malus which is Latin for “bad”, as in bad-tasting.

michael-pollan-apple-origin

Quote from Michael Pollan on the origin of apples in his book, The Botany of Desire

From Kazakhstan, the seeds of better-tasting and fleshier types of apples were dropped by traders along the Silk Road to Asia and to Europe, and eventually made their way to North America with the early colonists who planted apple orchards, spreading the apple genes throughout the northeast, and eventually throughout the U.S.

apple harvest-Kazakhstan

Apple harvest-Kazakhstan marketplace. At its center of origin, there are 56 species of the wild Malus species, only 30 of which have been semi- or wholly domesticated for apple production.

But apples, like humans, do not produce carbon copies of themselves in their seeds, so each seed in an apple is as different from another seed in that same apple or from another seed in an apple on the same tree, as children are different from each other and from their parents.  And this is where the human-apple tree mutualism becomes important in the spread of apples to every corner of the globe.

We humans perform much the same service that bees do in pollinating the apple’s flowers, by selective breeding for appealing varieties and then growing new trees of that variety from grafts merged onto hearty root stock.  In return, like the nectar and pollen the tree supplies to its pollinators, the apple tree repays its dispersers (animal and human alike) with crisp, sweet fruit that lasts several months when stored properly at cool temperatures.

What is it that makes apples so delicious and so appealing to us humans?

cross section of apple-

A cross section of a Honeycrisp apple (which I ate while writing this) shows the star-shaped endocarp housing the seeds. Each of the 5 chambers houses 1-2 seeds. The total number of seeds per apple (5-10) depends on the energy resources of the tree.

Around the star-shaped seed capsules are ten yellow-green dots that are the remnants of the flower stamens. The sepals (that surround the petals of the flower) are at one end of the apple, and the flower stem (now a fruit stem) is at the other. In between is the greatly expanded floral cup that grows up and around the ovary housing the soon-to-be seeds, and is filled with starch granules synthesized by the leaves over a summer’s worth of sunlight.  At the end of the summer as the skin takes on its rosy blush, those starch granules begin to break down to individual sugar molecules — and voila, sweet, juicy, crisp Fall apples are ready to be harvested.

honeycrisp apples

A sample of the harvest from just one of my dwarf honeycrisp trees. 

The Honeycrisp apple is an invention (!) of the University of Minnesota’s Agricultural Experiment Station Horticulture Research Center (quite a mouthful — pun intended).  As an experimental variety, it was almost cast aside because the tree was not cold tolerant and couldn’t survive Minnesota winters.  But the fruit was exceptionally pleasant, with large cells with stiff cell walls that stored great quantities of starch and water and a relatively thin skin that made biting into its crisp sweetness a gustatory delight.  Moving a few genes around to introduce cold heartiness made the next version of the Honeycrisp a winner — to markets and palates everywhere.

Can trees talk to each other?

How do trees talk to each other

Is this artists’ conception of tree communication real?  https://albertonrecord.co.za/182186/enviro-monday-trees-talk-via-wood-wide-web/

My apple trees are well synchronized with each other, so I have bumper crops of all 4 trees in alternate years.  Of course I want them to flower at the same time, so there is ample pollen for cross pollination of the different varieties.  However, this year, the trees were unusually productive…

Apple tree fruit production

There are hundreds of apples on my 4 trees, much more than can fit into my canning jars and refrigerator for long term storage.

Honeycrisp apples

Honeycrisp apples are reaching maximum ripeness, and attract passers by as well as the squirrels, birds, and deer that wander by for a sample.

Is it just coincidence that these trees are so well synchronized or do they somehow communicate with each other about their status?  A quick google search led me to a terrific article in Smithsonian magazine from March 2018 on this very question.

One way that trees, and plants in general, can communicate with each other is by way of the mutualistic fungi that entwine their combined roots.

How do trees talk to each other

Exchange of sugar (Carbon) and nutrients between fungi and roots and between trees.  https://albertonrecord.co.za/182186/enviro-monday-trees-talk-via-wood-wide-web/

The fungal strands search out and transport various nutrients that the plants need (nitrogen, calcium, phosphorus, magnesium, etc.) from the soil to the rootlets, and the trees pass photosynthesized sugars from the rootlets to the fungi in a very cooperative relationship.  But it goes beyond just the interaction between plant and fungi.

Research by Suzanne Simard (in a very interesting TED talk) has shown that individual trees in the forest are connected in a dense underground web of overlapping and intermingling roots and fungal associations, and this web consists not only of a “mother tree” and its seedlings, but trees of all ages of other species as well. Through these connections trees exchange carbon and other nutrients, paying a small tax to the fungi along the way.

Web of connection between forest trees, Beiler et al. 2010

A diagram of potential connections of forest trees (Beiler et al. 2010).  Large dark green circles are the busiest hubs (mother trees), sending carbon to other smaller trees, as well as their own seedlings (yellow dots) which may be growing in deep shade.

Not only are trees sharing resources in this busy underground network, but they are communicating with each other through secretion of plant hormones and volatile secondary compounds as well.  For example, Giraffes that munch on the leaves of one acacia tree will stimulate the production of distasteful tannins not only in the other leaves of that tree, but in its acacia neighbors as well.  In fact giraffes have learned to forage on the acacias that are downwind in a clump of trees to avoid this kind of response to the volatile chemicals released by the injured tree.

oak forest, Berkeley botanical garden, CA

Oak trees also produce chemical messages when under attack from herbivores, so that nearby oaks get a head start on ramping up tannin content of their leaves. I might have enhanced the “face” on the mother tree a little.  Photo from the Berkeley Botanical Garden, in a Backyard Biology post on Magical Oak Forests.

This kind of changes the way we look at forests, or even small patches of prairie, or garden plants, or shrubs growing together in our backyards.  These plants aren’t as much competitors as they are collaborators, existing side by side, in a mutual quest for light, water, and nutrients.  We could learn a lot from plants about cooperative existence!

Beautiful, but deceitful and poisonous!

What is beautiful, but deceitful and poisonous?  This blog usually focuses on things biological, so it must be an animal or a plant, and perhaps it could be either.  In this case it is the oleander shrub that fits that description.

Nerium oleander flowers

Beautiful pink flowers of the highly poisonous oleander 

Oleander is such a popular addition to roadside plantings and gardens that it now occurs world-wide in warm, wet Mediterranean type climates where its long-lasting profusion of white, pink, or red flowers brighten up the landscape.  It is remarkably drought-tolerant and protects itself from being munched by herbivores by sequestering toxic cardiac glycosides in its tissues, from its roots to the tips of its leaves.  No wonder it’s the dominant plant along freeways in California.

Large milkweed bug on Nerium oleander flowers

An indicator of oleander’s toxicity is the presence of insects, like the large milkweed bug, with warning coloration feeding on flower parts and seeds.

Oleander is, in fact, one of the more poisonous plants, but mammals, especially humans seem to be more sensitive to its toxins than birds.  However, folk tales about drifters during the Dust Bowl years dying from having stirred their stew with oleander twigs are probably false.

Clearly, oleander is beautiful and poisonous, but what about being deceitful?  How can a plant be deceitful?

Nerium oleander flowers

Oleander flowers are brightly colored, sometimes fragrant, with a central opening meant to entice pollinators to explore.

But oleander flowers produce no nectar, and thus there is no reward for pollinators to keep exploring the profusion of flowers on the plant.  It’s false advertising and deceptive on the part of the plant.  But does it work, that is, does enough pollination occur to allow seeds to be produced?

flowers and seed pods of Nerium oleander

How many flowers with no nectar reward will a pollinator visit before it gives up and moves on?

Apparently, insects that pollinated this oleander explored many of the flowers in a cluster, moving enough pollen to produce several seed pods.  But the number of seed pods on the entire plant is scanty.

flowers and seed pods of Nerium oleander

Only a single pod was produced in this group of flowers

The only good news for bee pollinators is that the lack of nectar in the flowers means they would not contaminate their honey with cardiac glycoside poisons.

Mid-summer scenes

Mid-summer, it’s the time when fruits are ripening, profusions of flowers light up backyards and prairies, and we see lots of birds, butterflies, and bees everywhere.  It might be hot and sticky, but this is the time we’ve been thinking about on those cold winter days.

Monarch butterfly on Shasta daisy

Monarchs have made it to Minnesota by July, and begin laying the generation of butterflies that may be the ones to migrate south in a couple of months.

Lake water warms up, and mats of water lilies and duck weed clog the shorelines.

Fish lake, Cedar Creek nature preserve, MN

Warm summer days, scenic Minnesota lakes, one of the more than 10,000.

Butterfly weed with Monarch and Fritillary butterflies

Butterfly milkweed is in full bloom, attracting butterflies and bees.

Sandhill Crane

Sandhill Cranes may have chicks following them around through the prairie meadows, and occasionally you see and hear them fly overhead.

Fruiting smooth sumac

Fruiting heads of smooth sumac light up the green forest of sumac shrubs. Did you know that the seed heads are high in vitamin C? Crush them in water to make sumac-ade!

Black morph, Tiger Swallowtail butterfly

The black morph of the Tiger Swallowtail butterfly has been visiting the backyard garden this week. It must be relatively newly emerged, with no bites in its wings yet.

Minnesota backyard in summer

What’s not to love about mid-summer days in the Minnesota backyard?

Morning visitors

It’s that time of the year again, when the bugs and the deer discover all the tasty plants in my garden.  While the Japanese beetles ravage the leaves of the apple trees and raspberries, the deer fawns chow down on the wildflowers.  I don’t mind them, though, they are pretty cute, and very shy.

White-tailed deer fawns

Breakfast at the wildflower garden buffet

White-tailed deer fawns

The twin is completely hidden underneath the giant cup plants.

White-tailed deer fawn

Hyssop must not taste good to deer; they left it for the bumblebees.