None; None; None; None

doi:10.15517/rev.biol.trop..v72i1.56175

Abstract

Introduction: Levee forests exhibit a vertical stratification that may contribute to structural complexity allowing a great diversity of birds to thrive on the islands. In deltaic ecosystems there is scarce or no data to prove it.

Objectives: To assess variations in the composition of the bird community within levee forests.

Methods: Two areas of protected wetlands belonging to the Paraná River Delta in Argentina were sampled for three years. A comparative analysis of richness, abundance, and diversity was performed in different levee forests using the point count method.

Results: Three distinct types of levee forests -open, intermediate, and closed- were identified based on the structure of their vegetation, hosting a total of 85 bird species. Variation in avian community structure among forest types revealed greater diversity in open forests during winter (3.26 ± 0.13, P < 0.01) and spring (3.58 ± 0.05, P < 0.01), and greater richness in autumn (35.33 ± 3.01, P < 0.01). The closed forests exhibited increased diversity during autumn (3.16 ± 0.13, P < 0.05) and summer (3.24 ± 0.06, P < 0.05), along with elevated abundance in autumn (114 ± 13.70, P < 0.05) and richness in spring (39.17 ± 4.71, P = 0.01). Due to the evolutionary history between sites, significant variation was observed in the most recently created national park, influencing abundance in winter (141 ± 22.06, P < 0.01) and spring (176 ± 12.83, P < 0.01), as well as diversity in winter (3.25 ± 0.10, P < 0.01) and spring (3.50 ± 0.10, P < 0.01).

Conclusions: The microhabitat in the different levee forests allows the birds to organize differently. Focusing on microspatial dynamics is key to a deep understanding of the biological processes within subtropical islands and to plan conservation strategies and demonstrate the transition of a recovering riparian forest towards its natural state, where the pulse of the river and the effect of seasonality do not stop operating.

Key words: microstructure; Ramsar site; bird community ecology; riparian environments; vegetation strata.

[TFN1] Seasonal variation in the community attributes related to forests structure. MMI: Multiple Model Inference. PDNP: Pre-Delta National Park. ISFNP: Islas de Santa Fe National Park. AICc value (small samples), delta and weight of the best model, coefficient value and standard deviation, confidence interval and P of the explanatory variables (*significance).

Dependent variable	Explanatory variable	Statistical (H)	P
Tree cover	Season	0.44	0.930
Shrub cover	Season	0.01	0.990
Herbaceous cover	Season	36.77	< 0.001*
Herbaceous height	Season	29.74	< 0.001*
Tree cover	Site	1.67	0.199
Shrub cover	Site	3.61	0.060
Herbaceous cover	Site	3.42	0.060
Herbaceous height	Site	0.62	0.430
Tree cover	Forest type	42.52	< 0.001*
Shrub cover	Forest type	34.71	< 0.001*
Herbaceous cover	Forest type	6.97	0.030 *
Herbaceous height	Forest type	18.69	< 0.001*

Dependent Variable	AICc	delta	Weight	Coeficient	Coef.Standard deviation	Confidence interval			p-value	Null deviance	Residual deviance	Devianza	Mean ± sd
						Explanatory variable	2.50 %	97.50 %
Winter Richness	MMI			-0.344	0.235	PDNP site	-0.842	0.153	0.175	-	-	-	-
Autumn Richness	104.50	2	0.57	35.333	1.452	Open forests*	32.49	38.18	< 0.01	304.00	189.67	37.61	35.33 ± 3.01
				-6.167	2.053	Closed forests*	-10.19	-2.14	< 0.01				29.17 ± 3.60
Spring Richness	MMI			-0.518	0.192	Closed forests*	-0.93	-0.11	0.01				39.17 ± 4.71
				-0.641	0.178	PDNP site*	-1.02	-0.26	< 0.01				38.78 ± 3.89
Summer Richness	MMI			-3.633 -5.674	1.506 1.506	Intermediate forests* Closed forest*	-1.05 -1.11	-0.01 -0.06	< 0.05 < 0.05				35.17 ± 3.31 34.67 ± 3.20
Winter Abundance	160.30	~2	0.59	-0.142	0.042	PDNP site*	-0.26	-0.02	< 0.05	23.53	18.00	23.49	122 ± 12.38
Winter Abundance				4.947	0.060	ISFNP site*	4.87	5.03	< 0.01				141 ± 22.06
Autumn Abundance	MMI			-0.005	0.002	Closed forests*	-0.01	0.00	< 0.05				114 ± 13.70
Spring Abundance	145.10	> 2	0.77	5.171	0.025	ISFNP site*	5.12	5.22	< 0.01	34.26	15.60	54.46	176 ± 12.83
				-0.160	0.037	PDNP site*	-0.23	-0.09	< 0.01				150 ± 12.37
Summer Abundance	MMI			-0.003	0.001	Intermediate forests*	-0.01	0.00	< 0.05				126 ± 17.85
				-0.004	0.001	PDNP site*	-0.01	0.00	< 0.01				122 ± 15.80
Winter Diversity	-26.60	~2	0.67	3.328	0.041	Open forests*	3.25	3.41	< 0.01	0.24	0.10	56.76	3.26 ± 0.13
				-0.157	0.050	Closed forests*	-0.26	-0.06	< 0.01				3.11 ± 0.07
				3.328	0.041	ISFNP site*	3.25	3.41	< 0.01				3.25 ± 0.10
				-0.118	0.041	PDNP site*	-0.20	-0.04	< 0.05				3.13 ± 0.11
Autumn Diversity	MMI			-0.962	0.375	Closed forests*	-1.73	-0.19	< 0.05				3.16 ± 0.13
				0.895	0.285	Closed forests in PDNP site*	0.27	1.52	< 0.01				3.18 ± 0.06
Spring Diversity	-28.10	> 2	0.77	3.590	0.039	Open forest*	3.51	3.67	< 0.01	0.26	0.10	63.08	3.58 ± 0.05
				-0.122	0.048	Intermediate forests*	-0.22	-0.03	< 0.05				3.40 ± 0.10
				-0.144	0.048	Closed forests*	-0.24	-0.05	< 0.01				3.37 ± 0.14
				3.590	0.039	ISFNP site*	3.51	3.67	< 0.01				3.50 ± 0.10
				-0.143	0.039	PDNP site*	-0.22	-0.07	< 0.01				3.36 ± 0.11
Summer Diversity	MMI			-0.629	0.244	Closed forests*	-1.15	-0.11	< 0.05				3.24 ± 0.06

Species	Status			ISFNP				PDNP
	Conservation			Richnnes			Number of Contacts			Richnnes			Number of Contacts
			OF	IF	CF	OF	IF	CF	OF	IF	CF	OF	IF	CF
Hydropsalis torquata*	LC	-	-	X	-	-	1	-	-	-	X	-	-	1
Butorides striata	LC	-	-	-	X	-	-	1	X	X	X	1	1	1
Columbina picui	LC	-	X	-	-	2	-	-	X	X	-	2	4	-
Columbina talpacoti	LC		X	-	-	1	-	-	X	X	X	5	1	2
Leptotila verreauxi	LC	-	X	X	X	62	85	95	X	X	X	105	142	155
Patagioenas maculosa	LC		X	-	-	1	-	-	-	-	-	-	-	-
Patagioenas picazuro	LC		X	X	X	39	53	61	X	X	X	60	75	74
Zenaida auriculata	LC		X	X	X	33	44	24	X	X	X	28	17	9
Chloroceryle amazona	LC		X	-	X	1	-	1	-	X	-	-	2	-
Chloroceryle americana	LC		X	-	X	2	-	2	X	X	-	1	3	-
Megaceryle torquata	LC	-	X	-	X	1	-	1	-	X	-	-	3	-
Coccycua cinérea*	LC		X	X	-	3	1	-	X	-	-	1	-	-
Coccyzus melacoryphus*	LC	-	X	X	X	4	1	4	X	X	X	2	2	3
Guira guira	LC		X	X	X	4	2	10	-	X	X	1	4	2
Tapera naevia*	LC	-	X	-	-	1	-	-	X	-	-	2	-	-
Rostrhamus sociabilis	LC	-	X	-	-	1	-	-	-	X	X	-	1	1
Rupornis magnirostris	LC		X	X	X	17	13	14	X	X	X	7	4	13
Caracara plancus	LC		X	X	X	8	5	5	X	X	X	19	6	9
Aramus guarauna	LC	-	-	-	X	-	-	1	-	-	-	-	-	-
Aramides ypecaha	LC		-	X	X	-	3	2	-	-	-	-	-	-
Campylorhamphus trochilirostris	LC		X	X	X	1	6	1	X	X	X	6	4	5
Lepidocolaptes angustirostris	LC		X	X	X	89	43	54	X	X	X	68	52	69
Microspingus melanoleucus	LC	-	X	X	X	44	15	7	X	X	X	11	7	5
Saltator aurantiirostris	LC	Unk	X	X	X	66	80	76	X	X	X	74	71	69
Saltator coerulescens	LC		X	X	X	124	162	134	X	X	X	126	114	125
Saltator similis	LC		-	X	-	-	1	-	-	-	-	-	-	-
Paroaria capitata	LC	-	X	X	X	45	26	45	X	X	X	22	5	8
Paroaria coronata	LC	-	X	X	X	27	24	23	X	X	X	25	13	17
Poospiza nigrorufa	LC	-	-	X	X	-	2	2	X	-	X	3	-	2
Sicalis flaveola	LC	-	X	X	X	6	9	2	X	X	X	4	8	4
Zonotrichia capensis	LC	-	X	X	X	30	35	47	X	X	X	16	9	22
Spinus magellanicus	LC	-	X	X	X	16	1	2	X	X	-	12	4	-
Asthenes pyrrholeuca**	LC		X	X	X	6	10	4	-	-	-	-	-	-
Certhiaxis cinnamomeus	LC		X	X	-	2	2	-	X	-	-	1	-	-
Phacellodomus ruber	LC		X	X	X	139	111	156	X	X	X	148	127	134
Phacellodomus striaticollis	LC	-	X	X	-	1	1	-	-	-	-	-	-	-
Synallaxis frontalis	LC		X	X	X	36	56	39	X	X	X	34	57	43
Limnoctites sulphuriferus	LC		X	X	X	1	2	4	-	-	-	-	-	-
Furnarius rufus	LC		X	X	X	56	70	66	X	X	X	53	48	62
Progne tapera*	LC		X	X	X	38	14	18	X	X	X	35	24	19
Tachycineta leucorrhoa	LC		X	X	X	55	31	17	X	X	X	27	13	16
Agelasticus cyanopus	LC	-	X	X	X	3	8	5	X	X	-	2	2	-
Cacicus solitarius	LC	-	X	X	X	4	17	5	X	X	X	14	9	23
Icterus pyrrhopterus	LC	-	X	X	X	28	10	18	X	X	X	18	13	13
Agelaioides badius	LC	-	X	X	X	52	54	39	X	X	X	26	39	23
Molothrus bonariensis	LC		X	X	X	7	4	5	X	X	X	9	7	1
Molothrus rufoaxillaris	LC	-	X	X	X	13	16	8	X	X	X	10	12	8
Geothlypis aequinoctialis	LC	-	X	X	X	1	1	2	X	-	X	2	-	1
Setophaga pitiayumi	LC		X	X	X	7	2	1	-	X	X	-	2	1
Myiothlypis leucoblephara	LC		-	-	-	-	-	-	X	X	X	9	12	38
Polioptila dumicola	LC		X	X	X	63	105	90	X	X	X	45	38	49
Taraba major	LC		X	X	X	72	68	59	X	X	X	69	65	54
Thamnophilus caerulescens	LC		-	X	X	-	9	8	X	X	X	3	6	12
Thlypopsis sordida	LC	-	X	X	X	7	13	3	X	X	-	4	2	-
Thraupis sayaca	LC	-	X	X	X	14	6	5	X	X	X	37	30	29
Turdus amaurochalinus	LC	-	X	X	X	42	23	22	X	X	X	38	39	31
Turdus rufiventris	LC	-	X	X	X	66	106	80	X	X	X	76	58	76
Troglodytes aedon	LC		X	X	X	30	10	9	X	X	X	20	14	7
Elaenia parvirostris	LC	-	X	X	X	5	3	2	-	X	-	-	1	-
Elaenia spectabilis	LC		X	X	X	1	10	6	X	X	X	3	5	4
Myiophobus fasciatus*	LC		X	X	X	7	4	6	X	X	X	3	6	3
Pitangus sulphuratus	LC		X	X	X	64	53	55	X	X	X	47	39	31
Serpophaga griseicapilla	LC	-	X	X	-	1	1	-	X	-	-	3	-	-
Serpophaga subcristata	LC	-	X	X	X	30	20	7	X	X	X	9	9	15
Hemitriccus margaritaceiventer	LC	-	X	X	X	11	21	12	X	X	X	2	2	11
Myiarchus swainsoni*	LC	-	X	X	X	15	12	9	X	X	X	13	11	9
Camptostoma obsoletum	LC	-	X	X	X	13	5	5	X	X	X	7	7	3
Myiodynastes maculatus*	LC	-	X	-	X	7	-	1	X	X	X	15	5	3
Suiriri suiriri	LC		X	X	X	33	17	7	X	X	X	31	12	11
Tyrannus melancholicus*	LC		X	X	X	9	12	14	X	X	X	10	10	14
Tyrannus savana*	LC	-	X	X	X	6	6	4	X	X	-	3	4	-
Machetornis rixosa	LC	-	X	X	X	1	2	2	X	-	-	1	-	-
Pachyramphus polychopterus*	LC	-	X	X	X	33	33	29	X	X	X	22	19	22
Pachyramphus viridis	LC	-	X	-	X	2	-	-	-	X	X	-	3	1
Vireo olivaceus*	LC		X	X	X	54	46	44	X	X	X	21	21	22
Cyclarhis gujanensis	LC		X	X	X	50	47	37	X	X	X	32	48	44
Colaptes melanochloros	LC	-	X	X	X	46	20	11	X	X	X	30	21	21
Melanerpes cactorum	LC		X	X	X	8	4	2	X	X	X	8	4	2
Melanerpes candidus	LC		X	X	-	4	1	-	-	X	-	-	2	-
Picumnus cirratus	LC		X	X	X	30	18	21	X	X	X	14	16	21
Dryobates mixtus	LC	-	X	X	X	35	19	20	X	X	X	29	21	32
Myiopsitta monachus	LC		X	X	X	6	21	21	X	X	X	14	43	35
Bubo virginianus	LC	-	-	X	-	-	5	-	X	-	-	2	-	-
Chlorostilbon lucidus	LC	Unk	X	X	X	3	4	4	X	X	X	1	6	1
Hylocharis chrysura	LC		X	X	X	19	25	15	X	X	X	11	16	10
			76	72	71	1 864	1 770	1611	69	69	69	1 612	1 500	1 551

Avian diversity in river levee forest: the effect of microscale heterogeneity

Diversidad de aves en bosques de albardón: el efecto de la heterogeneidad a microescala

Abstract